1
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Cheung CK, Alexander S, Reich HN, Selvaskandan H, Zhang H, Barratt J. The pathogenesis of IgA nephropathy and implications for treatment. Nat Rev Nephrol 2024:10.1038/s41581-024-00885-3. [PMID: 39232245 DOI: 10.1038/s41581-024-00885-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2024] [Indexed: 09/06/2024]
Abstract
IgA nephropathy (IgAN) is a common form of primary glomerulonephritis and represents an important cause of chronic kidney disease globally, with observational studies indicating that most patients are at risk of developing kidney failure within their lifetime. Several research advances have provided insights into the underlying disease pathogenesis, framed by a multi-hit model whereby an increase in circulating IgA1 that lacks galactose from its hinge region - probably derived from the mucosal immune system - is followed by binding of specific IgG and IgA antibodies, generating immune complexes that deposit within the glomeruli, which triggers inflammation, complement activation and kidney damage. Although treatment options are currently limited, new therapies are rapidly emerging that target different pathways, cells and mediators involved in the disease pathogenesis, including B cell priming in the gut mucosa, the cytokines APRIL and BAFF, plasma cells, complement activation and endothelin pathway activation. As more treatments become available, there is a realistic possibility of transforming the long-term outlook for many individuals with IgAN.
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Affiliation(s)
- Chee Kay Cheung
- Mayer IgA Nephropathy Laboratories, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.
- John Walls Renal Unit, University Hospitals of Leicester NHS Trust, Leicester, UK.
| | | | - Heather N Reich
- Department of Medicine, Division of Nephrology, University of Toronto, University Health Network, Toronto, ON, Canada
| | - Haresh Selvaskandan
- Mayer IgA Nephropathy Laboratories, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- John Walls Renal Unit, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Hong Zhang
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, P. R. China
| | - Jonathan Barratt
- Mayer IgA Nephropathy Laboratories, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.
- John Walls Renal Unit, University Hospitals of Leicester NHS Trust, Leicester, UK.
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Segura-Guerrero M, Saus C, Gozalbo-Rovira R, Cabello-Pelegrín S, Vargas ML, Martínez-Pomar N, Rodríguez-Díaz J, Saus J, Julià MR. Denovo glomerulonephritis associated with IgA anti-GBM alloantibodies after kidney transplantation in Alport syndrome: A case report with diagnostic implications. Clin Immunol 2024; 268:110354. [PMID: 39237079 DOI: 10.1016/j.clim.2024.110354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 07/03/2024] [Accepted: 08/28/2024] [Indexed: 09/07/2024]
Abstract
Alport syndrome (AS) is a hereditary disorder caused by pathogenic variants in COL4A3, COL4A4, or COL4A5 genes expressing α3, α4, and α5 chains of basement membrane type IV collagen (COL4). The triple-helical α3α4α5(IV) protomer is a major component of the mature glomerular basement membrane (GBM) whose defective formation in AS leads to structural GBM disruption and kidney dysfunction, often resulting in kidney replacement therapy. A genetically intact renal graft exposes the immune system to a non-tolerized α3α4α5(IV) component and an alloimmune response eventually ensues. So far, only IgG alloantibodies reacting against COL4 have been reported in AS alloimmune responses. Here, we report alloimmune glomerulonephritis mediated by IgA antibodies against the non-collagenous C-terminal domain 1 of the α5(IV) chain in a patient with autosomal recessive AS following a second kidney transplantation. The patient presented a not previously described biallelic variant in the COL4A4 gene. Immunological, diagnostic, and clinical implications are discussed.
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Affiliation(s)
- Marina Segura-Guerrero
- Immunology Department, Son Espases University Hospital, Balearic Islands Health Research Institute (IdISBa), Palma de Mallorca, Spain.
| | - Carlos Saus
- Pathology Department, Son Espases University Hospital, Balearic Islands Health Research Institute (IdISBa), Palma de Mallorca, Spain.
| | - Roberto Gozalbo-Rovira
- Microbiology Department, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain.
| | - Sheila Cabello-Pelegrín
- Nephrology Department, Son Espases University Hospital, Balearic Islands Health Research Institute (IdISBa), Palma de Mallorca, Spain.
| | | | - Natalia Martínez-Pomar
- Immunology Department, Son Espases University Hospital, Balearic Islands Health Research Institute (IdISBa), Palma de Mallorca, Spain.
| | - Jesús Rodríguez-Díaz
- Microbiology Department, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain.
| | - Juan Saus
- Biochemistry and Molecular Biology Department, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain.
| | - Maria Rosa Julià
- Immunology Department, Son Espases University Hospital, Balearic Islands Health Research Institute (IdISBa), Palma de Mallorca, Spain.
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3
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Yang M, Wang L, Sun XF, Yin DQ. Renal thrombotic microangiopathy is associated with poor renal survival in children with immunoglobulin A nephropathy. Nephrology (Carlton) 2024; 29:579-587. [PMID: 38716715 DOI: 10.1111/nep.14313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 03/16/2024] [Accepted: 04/24/2024] [Indexed: 08/17/2024]
Abstract
AIM The aim of this study was to examine the clinical and pathological characteristics as well as the prognosis of immunoglobulin A nephropathy (IgAN) accompanied by renal thrombotic microangiopathy (rTMA) in paediatric patients. METHODS After balancing epidemiological characteristics and pathological types between groups, 427 patients (rTMA group: 23, non-rTMA group: 46) were included. The clinical and pathological features, prognosis and clinical risk factors of the two groups were analysed. RESULTS IgAN-rTMA children showed more severe clinical and pathological manifestations. The findings from the logistic regression analysis indicated that hypercellularity 1 (E1) (HR: 0.805, 95% CI: 0.763 ~ 1.452, P = .016), endocapillary proliferation (HR: 1.214, 95% CI: 0.093 ~ 4.815, P = .025) and C3 staining (HR: 7.554, 95% CI: 2.563 ~ 15.729, P = .037) were the risk factors for rTMA in children with IgAN. The renal survival in rTMA group was lower than non-rTMA group (χ2 = 18.467, P = .000). Cox regression analysis showed that E1 (HR: 7.441, 95% CI: 1.095 ~ 10.768, P = .037), C3 disposition (HR: 3.414, 95% CI: 0.834 ~ 11.578, P = .027) and rTMA (HR: 8.918, 95% CI: 1.032 ~ 16.754, P = .041) were identified as independent risk factors for the development of end-stage renal disease (ESRD). CONCLUSION The presence of rTMA had a significant impact on the severity and prognosis of IgAN. And rTMA has been identified as an independent risk factor for the development of renal failure in children diagnosed with IgAN.
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Affiliation(s)
- Meng Yang
- Institute of Literature in Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Le Wang
- Department of Acupuncture and Moxibustion, Beijing GuLou hospital of Traditional Chinese Medicine, Beijing, China
| | - Xiong-Fei Sun
- Department of Pediatrics, Wuxi Deshu Clinic of Traditional Chinese Medicine, Wuxi, China
| | - Dong-Qi Yin
- Department of Pediatrics, First Clinical Medical College, Nanjing University of Chinese Medicine, Nanjing, China
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Kinashi Y, Tanaka K, Kimura S, Hirota M, Komiyama S, Shindo T, Hashiguchi A, Takahashi D, Shibata S, Karaki SI, Ohno H, Hase K. Intestinal epithelium dysfunctions cause IgA deposition in the kidney glomeruli of intestine-specific Ap1m2-deficient mice. EBioMedicine 2024; 106:105256. [PMID: 39059316 PMCID: PMC11338063 DOI: 10.1016/j.ebiom.2024.105256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 07/03/2024] [Accepted: 07/08/2024] [Indexed: 07/28/2024] Open
Abstract
BACKGROUND Intestinal epithelial cells (IECs) serve as robust barriers against potentially hostile luminal antigens and commensal microbiota. Epithelial barrier dysfunction enhances intestinal permeability, leading to leaky gut syndrome (LGS) associated with autoimmune and chronic inflammatory disorders. However, a causal relationship between LGS and systemic disorders remains unclear. Ap1m2 encodes clathrin adaptor protein complex 1 subunit mu 2, which facilitates polarized protein trafficking toward the basolateral membrane and contributes to the establishment of epithelial barrier functions. METHODS We generated IEC-specific Ap1m2-deficient (Ap1m2ΔIEC) mice with low intestinal barrier integrity as an LSG model and examined the systemic impact. FINDINGS Ap1m2ΔIEC mice spontaneously developed IgA nephropathy (IgAN)-like features characterized by the deposition of IgA-IgG immune complexes and complement factors in the kidney glomeruli. Ap1m2 deficiency markedly enhanced aberrantly glycosylated IgA in the serum owing to downregulation and mis-sorting of polymeric immunoglobulin receptors in IECs. Furthermore, Ap1m2 deficiency caused intestinal dysbiosis by attenuating IL-22-STAT3 signaling. Intestinal dysbiosis contributed to the pathogenesis of IgAN because antibiotic treatment reduced aberrantly glycosylated IgA production and renal IgA deposition in Ap1m2ΔIEC mice. INTERPRETATION IEC barrier dysfunction and subsequent dysbiosis by AP-1B deficiency provoke IgA deposition in the mouse kidney. Our findings provide experimental evidence of a pathological link between LGS and IgAN. FUNDING AMED, AMED-CREST, JSPS Grants-in-Aid for Scientific Research, JST CREST, Fuji Foundation for Protein Research, and Keio University Program for the Advancement of Next Generation Research Projects.
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Affiliation(s)
- Yusuke Kinashi
- Division of Biochemistry, Faculty of Pharmacy and Graduate School of Pharmaceutical Science, Keio University, Tokyo, Japan
| | - Keisuke Tanaka
- Division of Biochemistry, Faculty of Pharmacy and Graduate School of Pharmaceutical Science, Keio University, Tokyo, Japan
| | - Shunsuke Kimura
- Division of Biochemistry, Faculty of Pharmacy and Graduate School of Pharmaceutical Science, Keio University, Tokyo, Japan.
| | - Masato Hirota
- Division of Biochemistry, Faculty of Pharmacy and Graduate School of Pharmaceutical Science, Keio University, Tokyo, Japan
| | - Seiga Komiyama
- Division of Biochemistry, Faculty of Pharmacy and Graduate School of Pharmaceutical Science, Keio University, Tokyo, Japan
| | - Tomoko Shindo
- Electron Microscope Laboratory, Keio University School of Medicine, Tokyo, Japan
| | - Akinori Hashiguchi
- Electron Microscope Laboratory, Keio University School of Medicine, Tokyo, Japan; Depatment of Pathology, Keio University School of Medicine, Tokyo, Japan
| | - Daisuke Takahashi
- Division of Biochemistry, Faculty of Pharmacy and Graduate School of Pharmaceutical Science, Keio University, Tokyo, Japan
| | - Shinsuke Shibata
- Electron Microscope Laboratory, Keio University School of Medicine, Tokyo, Japan; Division of Microscopic Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Shin-Ichiro Karaki
- Laboratory of Physiology, Department of Environmental and Life Sciences, University of Shizuoka, Shizuoka, Japan
| | - Hiroshi Ohno
- RIKEN Center for Integrative Medical Sciences, Kanagawa, Japan; Immunobiology Laboratory, Graduate School of Medical Life Science, Yokohama City University, Kanagawa, Japan; Laboratory for Immune Regulation, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Koji Hase
- Division of Biochemistry, Faculty of Pharmacy and Graduate School of Pharmaceutical Science, Keio University, Tokyo, Japan; Institute of Fermentation Sciences (IFeS), Faculty of Food and Agricultural Sciences, Fukushima University, Fukushima, Japan; International Research and Development Center for Mucosal Vaccines, The Institute of Medical Science, The University of Tokyo (IMSUT), Tokyo, Japan.
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5
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Gan MY, Chua FZY, Chang ZY, Chua YT, Chan GC. Navigating Adult-Onset IgA Vasculitis-Associated Nephritis. Life (Basel) 2024; 14:930. [PMID: 39202674 PMCID: PMC11355272 DOI: 10.3390/life14080930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Revised: 07/14/2024] [Accepted: 07/16/2024] [Indexed: 09/03/2024] Open
Abstract
PURPOSE OF REVIEW IgA vasculitis (IgAV), formerly Henoch-Schonlein purpura, is the most common systemic vasculitis in childhood. In adults, however, this condition is poorly understood, yet associated with more severe disease and poorer outcomes. This necessitates the need for early diagnosis and management. SCOPE OF REVIEW We describe the pathophysiology, clinical manifestations, and diagnosis of IgAV in adults. Poor outcomes are often due to the high frequency of glomerulonephritis in IgAV-IgA vasculitis-associated nephritis (IgAVN). We hence also aim to summarize the latest clinical data regarding treatment strategies in IgAVN. The diagnosis and differentiation in histology between IgAVN and IgA nephropathy (IgAN) remain a challenge. Review of treatment therapies: Pathological mechanisms between IgAVN and IgAN appear to be consistent between the two, and data from IgAN are often extrapolated to IgAVN. The role of various immunosuppression therapies remains controversial, and in this review, we will discuss immunosuppression use and highlight evidence surrounding emerging and promising novel therapies in IgAVN/IgAN. Our aim for this review is to guide future treatment strategies and direct future studies.
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Affiliation(s)
- Ming Ying Gan
- Department of Medicine, National University Hospital, Singapore 119074, Singapore
| | - Freda Zhi Yun Chua
- Division of Nephrology, Department of Medicine, National University Hospital, Singapore 119074, Singapore
| | - Zi Yun Chang
- Division of Nephrology, Department of Medicine, National University Hospital, Singapore 119074, Singapore
- National University Centre for Organ Transplantation, National University Hospital, Singapore 119074, Singapore
| | - Yan Ting Chua
- Division of Nephrology, Department of Medicine, National University Hospital, Singapore 119074, Singapore
| | - Gek Cher Chan
- Division of Nephrology, Department of Medicine, National University Hospital, Singapore 119074, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
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Tringali E, Vetrano D, Tondolo F, Maritati F, Fabbrizio B, Pasquinelli G, Provenzano M, La Manna G, Baraldi O. Role of serum complement C3 and C4 on kidney outcomes in IgA nephropathy. Sci Rep 2024; 14:16224. [PMID: 39003309 PMCID: PMC11246413 DOI: 10.1038/s41598-024-65857-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 06/25/2024] [Indexed: 07/15/2024] Open
Abstract
IgA Nephropathy (IgAN) is the most prevalent glomerular disease worldwide. Complement system activation is crucial in its pathogenesis. Few studies correlated serum C3 and C4 with disease activity and prognosis. This retrospective study investigated the prognostic value of serum complement at the time of diagnosis in patients with IgAN. Specifically we evaluated whether adding serum C3 and C4 levels to established predictive models-one based on variables related to chronic kidney disease (CKD) progression and another incorporating variables from the International IgA Prediction Tool (IntIgAPT)-enhances the accuracy of outcome prediction. A composite renal outcome was defined as 50% decline in eGFR or onset of kidney failure. 101 patients were stratified according to baseline C3 levels in three groups (Low, Medium and High). During a median follow-up of 54 months, the Low group exhibited higher incidence of primary outcome (16.3 events vs 2.9 and 1.7 events × 100 pts/year, p = 0.0026). Model-1 (M1), consisting of CKD progression variables, and Model-3 (M3), comprising IntIgANPT variables, were implemented with baseline C3 and C4 to create Model-2 (M2) and Model-4 (M4), respectively. M2 demonstrated better predictive performance over M1, showing higher discrimination (lower AIC and BIC, higher C-index and NR2). Similarly, M4 outperformed M3, showing enhanced outcome prediction when C3 and C4 levels were added. Implementation of serum C3 and C4 can enhance prediction accuracy of already-validated prognostic models in IgAN. Lower C3 and higher C4 levels were associated with poorer prognosis, highlighting a more 'Complement-Pathic' subset of patients.
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Affiliation(s)
- Edoardo Tringali
- Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Daniele Vetrano
- Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Francesco Tondolo
- Nephrology, Dialysis and Kidney Transplant Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Federica Maritati
- Nephrology, Dialysis and Kidney Transplant Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Benedetta Fabbrizio
- Pathology Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Gianandrea Pasquinelli
- Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum University of Bologna, Bologna, Italy
- Pathology Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Michele Provenzano
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, CS, Italy.
| | - Gaetano La Manna
- Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum University of Bologna, Bologna, Italy.
- Nephrology, Dialysis and Kidney Transplant Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy.
| | - Olga Baraldi
- Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum University of Bologna, Bologna, Italy
- Nephrology and Dialysis Unit, Santa Maria delle Croci Hospital-Ravenna, AUSL Della Romagna, Ravenna, Italy
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Roberts LE, Williams CEC, Oni L, Barratt J, Selvaskandan H. IgA Nephropathy: Emerging Mechanisms of Disease. Indian J Nephrol 2024; 34:297-309. [PMID: 39156850 PMCID: PMC11326799 DOI: 10.25259/ijn_425_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 09/28/2023] [Indexed: 08/20/2024] Open
Abstract
Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis reported across the world and is characterized by immunoglobulin A (IgA) dominant mesangial deposits, which are poorly O-glycosylated. This deposition leads to a cascade of glomerular and tubulointerstitial inflammation and fibrosis, which can progress to chronic kidney disease. The variability in rate of progression reflects the many genetic and environmental factors that drive IgAN. Here, we summarize the contemporary understanding of the disease mechanisms that drive IgAN and provide an overview of new and emerging therapies, which target these mechanisms.
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Affiliation(s)
- Lydia E Roberts
- John Walls Renal Unit, University Hospitals of Leicester NHS Trust and University of Leicester, Leicester, United Kingdom
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Chloe E C Williams
- Royal Liverpool and Broadgreen University Hospital Trusts, Liverpool, United Kingdom
- Department of Women's and Children's Health, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Louise Oni
- Department of Women's and Children's Health, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
- Department of Paediatric Nephrology, Alder Hey Children's NHS Foundation Trust Hospital, Liverpool, United Kingdom
| | - Jonathan Barratt
- John Walls Renal Unit, University Hospitals of Leicester NHS Trust and University of Leicester, Leicester, United Kingdom
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
| | - Haresh Selvaskandan
- John Walls Renal Unit, University Hospitals of Leicester NHS Trust and University of Leicester, Leicester, United Kingdom
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
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Wang Y, Shang S, Jiang S, Zou G, Gao H, Li W. Complement C3a/C3aR and C5a/C5aR deposits accelerate the progression of advanced IgA nephropathy to end-stage renal disease. Clin Exp Med 2024; 24:139. [PMID: 38951265 PMCID: PMC11217045 DOI: 10.1007/s10238-024-01410-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2024] [Accepted: 06/19/2024] [Indexed: 07/03/2024]
Abstract
IgA nephropathy (IgAN) is still one of the leading causes of end-stage kidney disease (ESRD), and complement system activation is a key to the pathogenesis of IgAN. The role of complement C3a/C3aR and C5a/C5aR in late stage of IgAN remains unknown. Renal specimens of 75 IgAN patients at the stage 4 CKD were stained using immunofluorescence and immunohistochemistry. The primary outcome was a composite of end-stage renal disease (ESRD) and death. Associations of complement components with baseline clinicopathological characteristics and outcomes were assessed using multivariable Cox regression and Spearman analyses. During a median follow-up of 15.0 months, 27 patients progressed to ESRD and none died. Lower eGFR [hazards ratio (HR), 0.827, 95% confidence interval (CI), 0.732-0.935; P = 0.002] and glomerular C3 deposition (HR, 3.179, 95% CI, 1.079-9.363; P = 0.036) were predictive of time to ESRD in stage 4 CKD IgAN. Higher expression of C3a (P = 0.010), C3aR (P = 0.005), C5a (P = 0.015), and C5aR (P < 0.001) was identified in ESRD group than in non-ESRD group. Glomerular C3a/C3aR and C5a/C5aR deposits were both correlated with a lower baseline eGFR, higher baseline 24 h-urinary protein (24 h-UP) and faster decline of eGFR. Besides, C3a and C5a deposits were found in patients with high S (S1) and T (T1/2) scores, respectively. Complement C3a/C3aR and C5a/C5aR in IgAN patients with stage 4 CKD may portend a faster deterioration of kidney function.
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Affiliation(s)
- Ying Wang
- Department of Nephrology, China-Japan Friendship Hospital, No. 2 East Yinghuayuan Street, Chaoyang District, Beijing, 100029, China
| | - Shunlai Shang
- Department of Nephrology, China-Japan Friendship Hospital, No. 2 East Yinghuayuan Street, Chaoyang District, Beijing, 100029, China.
| | - Shimin Jiang
- Department of Nephrology, China-Japan Friendship Hospital, No. 2 East Yinghuayuan Street, Chaoyang District, Beijing, 100029, China
| | - Guming Zou
- Department of Nephrology, China-Japan Friendship Hospital, No. 2 East Yinghuayuan Street, Chaoyang District, Beijing, 100029, China
| | - Hongmei Gao
- Department of Nephrology, China-Japan Friendship Hospital, No. 2 East Yinghuayuan Street, Chaoyang District, Beijing, 100029, China
| | - Wenge Li
- Department of Nephrology, China-Japan Friendship Hospital, No. 2 East Yinghuayuan Street, Chaoyang District, Beijing, 100029, China.
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9
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Kohan DE, Bedard P, Jenkinson C, Hendry B, Komers R. Mechanism of protective actions of sparsentan in the kidney: lessons from studies in models of chronic kidney disease. Clin Sci (Lond) 2024; 138:645-662. [PMID: 38808486 PMCID: PMC11139641 DOI: 10.1042/cs20240249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 05/08/2024] [Accepted: 05/09/2024] [Indexed: 05/30/2024]
Abstract
Simultaneous inhibition of angiotensin II AT1 and endothelin ETA receptors has emerged as a promising approach for treatment of chronic progressive kidney disease. This therapeutic approach has been advanced by the introduction of sparsentan, the first dual AT1 and ETA receptor antagonist. Sparsentan is a single molecule with high affinity for both receptors. It is US Food and Drug Administration approved for immunoglobulin A nephropathy (IgAN) and is currently being developed as a treatment for rare kidney diseases, such as focal segmental glomerulosclerosis. Clinical studies have demonstrated the efficacy and safety of sparsentan in these conditions. In parallel with clinical development, studies have been conducted to elucidate the mechanisms of action of sparsentan and its position in the context of published evidence characterizing the nephroprotective effects of dual ETA and AT1 receptor inhibition. This review summarizes this evidence, documenting beneficial anti-inflammatory, antifibrotic, and hemodynamic actions of sparsentan in the kidney and protective actions in glomerular endothelial cells, mesangial cells, the tubulointerstitium, and podocytes, thus providing the rationale for the use of sparsentan as therapy for focal segmental glomerulosclerosis and IgAN and suggesting potential benefits in other renal diseases, such as Alport syndrome.
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Affiliation(s)
- Donald E. Kohan
- Division of Nephrology, University of Utah Health, Salt Lake City, UT, U.S.A
| | | | | | - Bruce Hendry
- Travere Therapeutics, Inc., San Diego, CA, U.S.A
| | - Radko Komers
- Travere Therapeutics, Inc., San Diego, CA, U.S.A
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10
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Guo WY, Wang GQ, Kong LQ, Sun LJ, Xu XY, Cheng WR, Dong HR, Cheng H. Complement system is overactivated in patients with IgA nephropathy after COVID-19. Clin Immunol 2024; 263:110232. [PMID: 38701960 DOI: 10.1016/j.clim.2024.110232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 04/26/2024] [Indexed: 05/06/2024]
Abstract
IgA nephropathy (IgAN), which has been confirmed as a complement mediated autoimmune disease, is also one form of glomerulonephritis associated with COVID-19. Here, we aim to investigate the clinical and immunological characteristics of patients with IgAN after COVID-19. The level of plasma level of C5a (p < 0.001), soluble C5b-9 (p = 0.018), FHR5 (p < 0.001) were all significantly higher in Group CoV (33 patients with renal biopsy-proven IgAN experienced COVID-19) compared with Group non-CoV (44 patients with IgAN without COVID-19), respectively. Compared with Group non-CoV, the intensity of glomerular C4d (p = 0.017) and MAC deposition (p < 0.001) and Gd-IgA1 deposition (p = 0.005) were much stronger in Group CoV. Our finding revealed that for IgAN after COVID-19, mucosal immune responses to SARS-CoV-2 infection may result in the overactivation of systemic and renal local complement system, and increased glomerular deposition of Gd-IgA1, which may lead to renal dysfunction and promote renal progression in IgAN patients.
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Affiliation(s)
- Wei-Yi Guo
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, China
| | - Guo-Qin Wang
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, China
| | - Ling-Qiang Kong
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, China
| | - Li-Jun Sun
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, China
| | - Xiao-Yi Xu
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, China
| | - Wen-Rong Cheng
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, China
| | - Hong-Rui Dong
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, China
| | - Hong Cheng
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, China.
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11
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Watanabe-Kusunoki K, Anders HJ. Balancing efficacy and safety of complement inhibitors. J Autoimmun 2024; 145:103216. [PMID: 38552408 DOI: 10.1016/j.jaut.2024.103216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/17/2024] [Accepted: 03/26/2024] [Indexed: 05/15/2024]
Abstract
Complement inhibitors have been approved for several immune-mediated diseases and they are considered the next paradigm-shifting approach in the treatment of glomerulonephritis. The hierarchical organization of the complement system offers numerous molecular targets for therapeutic intervention. However, complement is an integral element of host defense and therefore complement inhibition can be associated with serious infectious complications. Here we give a closer look to the hierarchical complement system and how interfering with proximal versus distal or selective versus unselective molecular targets could determine efficacy and safety. Furthermore, we propose to consider the type of disease, immunological activity, and patient immunocompetence when stratifying patients, e.g., proximal/unselective targets for highly active and potentially fatal diseases while distal and selective targets may suit more chronic disease conditions with low or moderate disease activity requiring persistent complement blockade in patients with concomitant immunodeficiency. Certainly, there exists substantial promise for anti-complement therapeutics. However, balancing efficacy and safety will be key to establish powerful treatment effects with minimal adverse events, especially when complement blockade is continued over longer periods of time in chronic disorders.
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Affiliation(s)
- Kanako Watanabe-Kusunoki
- Renal Division, Department of Medicine IV, Ludwig-Maximilians (LMU) University Hospital, LMU Munich, Germany; Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hans-Joachim Anders
- Renal Division, Department of Medicine IV, Ludwig-Maximilians (LMU) University Hospital, LMU Munich, Germany.
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12
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Cetinkaya H, Gursu M, Yazici H, Cebeci E, Eren N, Altiparmak MR, Akcay OF, Sahin G, Dheir H, Basturk T, Atilgan KG, Aydemir N, Turgutalp K, Yilmaz M, Sirali SK, Tatar E, Boz EG, Mirioglu S, Kazan S, Aydin E, Aydin Z, Turkmen K, Kutlay S, Karagoz F, Ogutmen MB, Ozturk S, Ozkan O, Yildiz N, Dincer T, Yasar E, Gok M, Turkmen A, Dede F, Derici U. Could mesangial C3 deposition be an independent prognostic marker in immunoglobulin A nephropathy? J Nephrol 2024; 37:923-932. [PMID: 37947938 DOI: 10.1007/s40620-023-01770-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 08/18/2023] [Indexed: 11/12/2023]
Abstract
BACKGROUND Immunoglobulin A nephropathy (IgAN) is a common primary glomerulonephropathy. There is evidence that mesangial C3 deposition plays a role in the development of the disease. The aim of this study was to examine the effect of C3 deposition on the prognosis of IgAN patients. METHOD The study included 1135 patients with biopsy-confirmed IgAN from the database of the Turkish Nephrology Association Glomerular Diseases Working Group (TSN-GOLD). Patients were excluded from the study if they were aged < 18 or > 75 years or if C3 staining had not been performed in the immunofluorescent analysis. C3 deposition was defined as an immunofluorescence intensity of C3 ≥ 2 + within the mesangium. The primary endpoints were the development of end-stage renal disease, a 30% decrease in glomerular filtration rate compared to the basal value or an elevation in proteinuria to a nephrotic level (3.5 gr/day). RESULTS Mesangial C3 deposition was observed in 603 (53.1%) patients. No statistically significant difference was found at baseline between the groups with and without mesangial C3 deposition, as for age, sex, BMI, proteinuria level, or the presence of hypertension. In the follow-up period with a mean duration of 78 months, no significant difference was found between the two groups regarding the primary endpoints (p = 0.43). A significant correlation between C3 deposition and segmental glomerulosclerosis (S1) according to the Oxford MEST-C classification was found (p = 0.001). CONCLUSION Although a correlation was observed between mesangial C3 deposition and the S1 MEST-C classification, mesangial C3 deposition was not a prognostic factor in IgAN.
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Affiliation(s)
- Hakki Cetinkaya
- Department of Nephrology, Sultan Abdulhamid Han Training and Research Hospital, University of Health Sciences, Istanbul, Turkey.
| | - Meltem Gursu
- Medical Faculty, Nephrology, Bezmialem Vakif University, Istanbul, Turkey
| | - Halil Yazici
- Istanbul Medical Faculty, Nephrology, Istanbul University, Istanbul, Turkey
| | - Egemen Cebeci
- Department of Nephrology, Haseki Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Necmi Eren
- Medical Faculty, Nephrology, Kocaeli University, Izmit, Kocaeli, Turkey
| | | | | | - Gulizar Sahin
- Department of Nephrology, Sultan Abdulhamid Han Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Hamad Dheir
- Medical Faculty, Nephrology, Sakarya University, Adapazari, Sakarya, Turkey
| | - Taner Basturk
- Department of Nephrology, Sisli Hamidiye Etfal Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Kadir Gokhan Atilgan
- Department of Nephrology, Diskapi Training and Research Hospital, University of Health Sciences, Ankara, Turkey
| | - Nihal Aydemir
- Department of Nephrology, Ankara Bilkent City Hospital, University of Health Sciences, Ankara, Turkey
| | - Kenan Turgutalp
- Division of Nephrology, Department of Internal Medicine, Mersin University School of Medicine, Mersin, Turkey
| | - Murvet Yilmaz
- Department of Nephrology, Bakirkoy Dr. Sadi Konuk Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Semahat Karahisar Sirali
- Department of Nephrology, Ankara Training and Research Hospital, University of Health Sciences, Ankara, Turkey
| | - Erhan Tatar
- Department of Nephrology, Bozyaka Training and Research Hospital, University of Health Sciences, Izmir, Turkey
| | - Elif Gullulu Boz
- Division of Nephrology, Department of Internal Medicine, Uludag University School of Medicine, Bursa, Turkey
| | - Safak Mirioglu
- Medical Faculty, Nephrology, Bezmialem Vakif University, Istanbul, Turkey
| | - Sinan Kazan
- Department of Nephrology, Afyonkarahisar School of Medicine, University of Health Sciences, Afyonkarahisar, Turkey
| | - Emre Aydin
- Medical Faculty, Nephrology, Dicle University, Diyarbakir, Turkey
| | - Zeki Aydin
- Department of Nephrology, Darica Farabi Training and Research Hospital, University of Health Sciences, Darica, Kocaeli, Turkey
| | - Kultigin Turkmen
- Meram Medical Faculty, Nephrology, Necmettin Erbakan University, Konya, Turkey
| | - Sim Kutlay
- Medical Faculty, Nephrology, Ankara University, Ankara, Turkey
| | - Ferdi Karagoz
- Medical Faculty, Nephrology, Trakya University, Edirne, Turkey
| | - Melike Betul Ogutmen
- Department of Nephrology, Haydarpasa Numune Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Savas Ozturk
- Istanbul Medical Faculty, Nephrology, Istanbul University, Istanbul, Turkey
| | - Oktay Ozkan
- Department of Nephrology, Haseki Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Nuriye Yildiz
- Medical Faculty, Nephrology, Kocaeli University, Izmit, Kocaeli, Turkey
| | - Tamer Dincer
- Cerrahpasa Medical Faculty, Nephrology, Istanbul University, Istanbul, Turkey
| | - Emre Yasar
- Medical Faculty, Nephrology, Gazi University, Ankara, Turkey
| | - Mahmut Gok
- Department of Nephrology, Sultan Abdulhamid Han Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Aydın Turkmen
- Istanbul Medical Faculty, Nephrology, Istanbul University, Istanbul, Turkey
| | - Fatih Dede
- Department of Nephrology, Ankara Bilkent City Hospital, University of Health Sciences, Ankara, Turkey
| | - Ulver Derici
- Medical Faculty, Nephrology, Gazi University, Ankara, Turkey
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13
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Rossi GM, Ricco F, Pisani I, Delsante M, Maggiore U, Fiaccadori E, Manenti L. C3 Hypocomplementemia Predicts the Progression of CKD towards End-Stage Kidney Disease in IgA Nephropathy, Irrespective of Histological Evidence of Thrombotic Microangiopathy. J Clin Med 2024; 13:2594. [PMID: 38731122 PMCID: PMC11084933 DOI: 10.3390/jcm13092594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/16/2024] [Accepted: 04/18/2024] [Indexed: 05/13/2024] Open
Abstract
Background: IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. IgAN causes end-stage kidney disease (ESKD) in 30-40% of all cases. The activation of the complement system by pathological circulating IgAs, which is often associated with low serum C3 levels (LowC3), seems to play a crucial role. Previous studies have shown an association between histological evidence of TMA, which is the result of alternative complement activation, and poor outcomes. However, it is not known to what extent the decrease in serum C3 levels reflects ongoing TMA injury. Our study aimed at assessing the association between LowC3 and ESKD and whether this association reflects ongoing TMA. Methods: We enrolled all patients with biopsy-proven IgAN and followed-up patients until their last visit, ESKD, or death. Results: Of the 56 patients included in the study, 12 (21%) presented low serum C3 (LowC3) at the time of renal biopsy. TMA was significantly more frequent in the LowC3 group [7/12 (58%) vs. 9/44 (20%), p = 0.02]. After adjusting for potential confounders, LowC3 was strongly associated with an increased hazard of ESKD (hazard ratio [HR]: 5.84 [95%CI: 1.69, 20.15; p = 0.005). The association was not affected by adjusting for TMA. The estimated overall proportion of the relation between C3 and ESKD mediated by TMA was low and not statistically significant. Conclusions: Our study provides evidence that C3 hypocomplementemia is associated with an increased risk of ESKD through mechanisms that are largely independent from TMA.
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Affiliation(s)
- Giovanni Maria Rossi
- Nephrology Unit, University Hospital of Parma, 43126 Parma, Italy; (G.M.R.); (F.R.); (I.P.); (M.D.); (U.M.); (E.F.)
| | - Federico Ricco
- Nephrology Unit, University Hospital of Parma, 43126 Parma, Italy; (G.M.R.); (F.R.); (I.P.); (M.D.); (U.M.); (E.F.)
| | - Isabella Pisani
- Nephrology Unit, University Hospital of Parma, 43126 Parma, Italy; (G.M.R.); (F.R.); (I.P.); (M.D.); (U.M.); (E.F.)
| | - Marco Delsante
- Nephrology Unit, University Hospital of Parma, 43126 Parma, Italy; (G.M.R.); (F.R.); (I.P.); (M.D.); (U.M.); (E.F.)
| | - Umberto Maggiore
- Nephrology Unit, University Hospital of Parma, 43126 Parma, Italy; (G.M.R.); (F.R.); (I.P.); (M.D.); (U.M.); (E.F.)
- Dipartimento di Medicina e Chirurgia, Università di Parma, 43126 Parma, Italy
| | - Enrico Fiaccadori
- Nephrology Unit, University Hospital of Parma, 43126 Parma, Italy; (G.M.R.); (F.R.); (I.P.); (M.D.); (U.M.); (E.F.)
- Dipartimento di Medicina e Chirurgia, Università di Parma, 43126 Parma, Italy
| | - Lucio Manenti
- Nephrology Unit, Azienda Sociosanitaria Liguria 5, 19121 La Spezia, Italy
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14
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Obrișcă B, Mocanu V, Jurubiță R, Vrabie A, Berechet A, Lujinschi Ș, Sorohan B, Andronesi A, Achim C, Lupușoru G, Micu G, Caceaune N, Gherghiceanu M, Ismail G. Histological reappraisal of IgA nephropathy: the role of glomerular pattern of injury and mesangial complement deposition. BMC Nephrol 2024; 25:145. [PMID: 38658875 PMCID: PMC11040743 DOI: 10.1186/s12882-024-03577-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 04/11/2024] [Indexed: 04/26/2024] Open
Abstract
BACKGROUND There is a clear need to refine the histological assessment in IgA Nephropathy (IgAN). We sought to investigate the clinical significance of the light microscopy (LM) pattern of glomerular injury and of the intensity of mesangial C3 staining in IgAN. METHODS We conducted a retrospective, observational study that included all patients with biopsy-proven primary IgAN that had at least 12 months of follow-up. The LM pattern of glomerular injury was reevaluated based on a modified HAAS classification. Mesangial C3 deposition by immunofluorescence (IF) staining was scored semi-quantitatively. The study primary composite endpoint was defined as doubling of serum creatinine or ESRD (dialysis, renal transplant or eGFR < 15 ml/min). The secondary study endpoint was eGFR decline per year. RESULTS This cohort included 214 patients with IgAN (mean age, 41.4 ± 12.6 years), with a mean eGFR and median 24-h proteinuria of 55.2 ± 31.5 ml/min/1.73m2 and 1.5 g/day (IQR:0.8-3.25), respectively. The most frequent LM pattern was the mesangioproliferative (37.4%), followed by the sclerotic (22.5%) and proliferative/necrotizing patterns (21.4%). Regarding the IF findings, mild-moderate and intense mesangial C3 staining was present in 30.6% and 61.1% of patients, respectively. Those with sclerosing and crescentic patterns had the worst renal survival (5-year renal survival of 48.8% and 42.9%) and the highest rate of eGFR change/year (-2.32 ml/min/y and - 2.16 ml/min/y, respectively) compared to those with other glomerular patterns of injury. In addition, those with intense C3 staining reached the composite endpoint more frequently compared to those without intense C3 staining (35.5% vs. 21.4%, p = 0.04). After multivariate adjustment, patients with crescentic and sclerosing patterns had a 3.6-fold and 2.1-fold higher risk for the composite endpoint compared to those with mesangioproliferative pattern, while an intense mesangial C3 deposition being also associated with a worse renal outcome (HR, 3.33; 95%CI, 1.21-9.2). CONCLUSIONS We have shown that the LM pattern of glomerular injury and the intensity of mesangial C3 deposition might stratify more accurately the renal outcome in patients with IgAN.
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Affiliation(s)
- Bogdan Obrișcă
- "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania.
- Department of Nephrology, Fundeni Clinical Institute, Bucharest, Romania.
| | - Valentin Mocanu
- "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
- Department of Nephrology, Fundeni Clinical Institute, Bucharest, Romania
| | - Roxana Jurubiță
- "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
- Department of Nephrology, Fundeni Clinical Institute, Bucharest, Romania
| | - Alexandra Vrabie
- "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
- Department of Nephrology, Fundeni Clinical Institute, Bucharest, Romania
| | - Andreea Berechet
- Department of Nephrology, Fundeni Clinical Institute, Bucharest, Romania
| | - Ștefan Lujinschi
- "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
- Department of Nephrology, Fundeni Clinical Institute, Bucharest, Romania
| | - Bogdan Sorohan
- "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
- Department of Nephrology, Fundeni Clinical Institute, Bucharest, Romania
| | - Andreea Andronesi
- "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
- Department of Nephrology, Fundeni Clinical Institute, Bucharest, Romania
| | - Camelia Achim
- "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
- Department of Nephrology, Fundeni Clinical Institute, Bucharest, Romania
| | - Gabriela Lupușoru
- "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
- Department of Nephrology, Fundeni Clinical Institute, Bucharest, Romania
| | - Georgia Micu
- Department of Nephrology, Fundeni Clinical Institute, Bucharest, Romania
| | - Nicu Caceaune
- Department of Internal Medicine, Fundeni Clinical Institute, Bucharest, Romania
| | - Mihaela Gherghiceanu
- "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
- "Victor Babes" National Institute of Pathology, Bucharest, Romania
| | - Gener Ismail
- "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
- Department of Nephrology, Fundeni Clinical Institute, Bucharest, Romania
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15
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Chiarenza DS, Verrina EE, La Porta E, Caridi G, Ghiggeri GM, Mortari G, Lugani F, Angeletti A, Bigatti C. Biologics and Non-Biologics Immunosuppressive Treatments for IgA Nephropathy in Both Adults and Children. J Clin Med 2024; 13:2465. [PMID: 38730994 PMCID: PMC11084942 DOI: 10.3390/jcm13092465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/14/2024] [Accepted: 04/16/2024] [Indexed: 05/13/2024] Open
Abstract
Immunoglobulin A nephropathy represents the most prevalent cause of glomerulonephritis worldwide and may lead to renal failure in a relevant number of cases in both paediatric and adult subjects. Although their pathogenesis is still largely unclear, evidence of immune abnormalities provides the background for the use of immunosuppressive drugs, such as corticosteroids, calcineurin inhibitors, and antiproliferative and alkylating agents. Unfortunately, these treatments fail to achieve a sustained remission in a significant percentage of affected patients and are burdened by significant toxicities. Recent developments of new biologics, including anti-BAFF/APRIL inhibitors and molecules targeting complement components, offered the opportunity to selectively target immune cell subsets or activation pathways, leading to more effective and safer hypothesis-driven treatments. However, studies testing new biologic agents in IgAN should also consider paediatric populations to address the unique needs of children and close the therapeutic gap between adult and paediatric care.
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Affiliation(s)
| | | | | | | | | | | | | | - Andrea Angeletti
- Nephrology, Dialysis and Transplantation Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy; (D.S.C.); (E.E.V.); (E.L.P.); (G.C.); (G.M.G.); (G.M.); (F.L.); (C.B.)
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16
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Qu S, Zhou XJ, Zhang H. Genetics of IgA nephrology: risks, mechanisms, and therapeutic targets. Pediatr Nephrol 2024:10.1007/s00467-024-06369-7. [PMID: 38600219 DOI: 10.1007/s00467-024-06369-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/24/2024] [Accepted: 03/28/2024] [Indexed: 04/12/2024]
Abstract
IgA nephropathy (IgAN) is a genetically complex multifactorial trait. Over the past decade, population-based genome-wide association studies (GWAS) have identified more than 30 IgAN risk loci, providing novel perspectives on both the epidemiology of the disease and its underlying molecular mechanisms. In addition, the association between IgAN and galactose-deficient IgA1 (Gd-IgA1) presented another avenue for genetic exploration due to the heritability of the elevated serum Gd-IgA1 levels. These endeavors also yielded and enabled refinement of polygenic risk scores, which may help identify specific groups of individuals at significantly increased risks, leading to stratifications of medical treatments. In this review, we aim to explore the existing evidence for genetic causation in IgAN. We summarize the state of genetic research in IgAN and how it has led to the reformulation of the new pathogenesis model and novel therapeutic targets.
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Affiliation(s)
- Shu Qu
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, No. 8, Xishiku Street, Xicheng District, Beijing, 100034, People's Republic of China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, People's Republic of China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education, Peking University, Beijing, People's Republic of China
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Xu-Jie Zhou
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, No. 8, Xishiku Street, Xicheng District, Beijing, 100034, People's Republic of China.
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, People's Republic of China.
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education, Peking University, Beijing, People's Republic of China.
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.
| | - Hong Zhang
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, No. 8, Xishiku Street, Xicheng District, Beijing, 100034, People's Republic of China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, People's Republic of China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education, Peking University, Beijing, People's Republic of China
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
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17
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Gao MZ, Xu LL, Li Y, Wang X, Chen P, Shi SF, Liu LJ, Lv JC, Hong FY, Zhang H, Zhou XJ. Hepatitis B Virus Status and Clinical Outcomes in IgA Nephropathy. Kidney Int Rep 2024; 9:1057-1066. [PMID: 38765575 PMCID: PMC11101714 DOI: 10.1016/j.ekir.2024.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/26/2023] [Accepted: 01/02/2024] [Indexed: 05/22/2024] Open
Abstract
Introduction Immunoglobulin A nephropathy (IgAN) has been reported to coexist with hepatitis B virus (HBV) infection. Despite the clinical significance of this association, there is a lack of comprehensive research investigating the impact of various common conditions following HBV infection and the potential influence of anti-HBV therapy on the progression of IgAN. Methods We investigated 3 distinct states of HBV infection, including chronic HBV infection, resolved HBV infection, and the deposition of hepatitis B antigens in renal tissue, in a follow-up database of 1961 patients with IgAN. IgAN progression was defined as a loss of estimated glomerular filtration rate (eGFR) >40%. Multivariable cause-specific hazards models to analyze the relationship between HBV states and IgAN progression. Results Chronic HBV infection was identified as an independent risk factor for IgAN progression, supported by both prematching analysis (hazard ratio [HR], 1.61; 95% confidence interval [CI], 1.06-2.44; P = 0.024) and propensity-score matching analysis (HR, 1.74; 95% CI 1.28-2.37; P < 0.001). Conversely, resolved HBV infection showed no significant association with IgAN progression (HR, 1.01; 95% CI 0.67-1.52; P = 0.969). Moreover, the presence of HBV deposition in the kidneys and the utilization of anti-HBV therapy did not appear to be significant risk factors for renal outcomes (P > 0.05). Conclusion Chronic HBV infection is an independent risk factor for IgAN progression, whereas resolved HBV infection is not. In patients with IgAN, management of concurrent chronic HBV infection should be enhanced. The presence of HBV deposition in the kidneys and the use of anti-HBV medications do not impact the kidney disease progression in patients with IgAN with concurrent HBV infection.
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Affiliation(s)
- Mei-zhu Gao
- Renal Division, Peking University First Hospital; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education; Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
- Department of Nephrology, Fujian Provincial Hospital, Shengli Clinical College of Fujian Medical University, Fuzhou, China
| | - Lin-lin Xu
- Renal Division, Peking University First Hospital; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education; Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Yang Li
- Renal Division, Peking University First Hospital; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education; Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Xin Wang
- Renal Division, Peking University First Hospital; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education; Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Pei Chen
- Renal Division, Peking University First Hospital; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education; Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Su-fang Shi
- Renal Division, Peking University First Hospital; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education; Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Li-jun Liu
- Renal Division, Peking University First Hospital; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education; Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Ji-cheng Lv
- Renal Division, Peking University First Hospital; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education; Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Fu-Yuan Hong
- Department of Nephrology, Fujian Provincial Hospital, Shengli Clinical College of Fujian Medical University, Fuzhou, China
| | - Hong Zhang
- Renal Division, Peking University First Hospital; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education; Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Xu-jie Zhou
- Renal Division, Peking University First Hospital; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education; Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
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18
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Rivedal M, Mikkelsen H, Marti HP, Liu L, Kiryluk K, Knoop T, Bjørneklett R, Haaskjold YL, Furriol J, Leh S, Paunas F, Bábíčková J, Scherer A, Serre C, Eikrem O, Strauss P. Glomerular transcriptomics predicts long term outcome and identifies therapeutic strategies for patients with assumed benign IgA nephropathy. Kidney Int 2024; 105:717-730. [PMID: 38154557 DOI: 10.1016/j.kint.2023.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/17/2023] [Accepted: 12/08/2023] [Indexed: 12/30/2023]
Abstract
Some patients diagnosed with benign IgA nephropathy (IgAN) develop a progressive clinical course, not predictable by known clinical or histopathological parameters. To assess if gene expression can differentiate between progressors and non-progressors with assumed benign IgAN, we tested microdissected glomeruli from archival kidney biopsy sections from adult patients with stable clinical remission (21 non-progressors) or from 15 patients that had undergone clinical progression within a 25-year time frame. Based on 1 240 differentially expressed genes from patients with suitable sequencing results, we identified eight IgAN progressor and nine non-progressor genes using a two-component classifier. These genes, including APOL5 and ZXDC, predicted disease progression with 88% accuracy, 75% sensitivity and 100% specificity on average 21.6 years before progressive disease was clinically documented. APOL lipoproteins are associated with inflammation, autophagy and kidney disease while ZXDC is a zinc-finger transcription factor modulating adaptive immunity. Ten genes from our transcriptomics data overlapped with an external genome wide association study dataset, although the gene set enrichment test was not statistically significant. We also identified 45 drug targets in the DrugBank database, including angiotensinogen, a target of sparsentan (dual antagonist of the endothelin type A receptor and the angiotensin II type 1 receptor) currently investigated for IgAN treatment. Two validation cohorts were used for substantiating key results, one by immunohistochemistry and the other by nCounter technology. Thus, glomerular mRNA sequencing from diagnostic kidney biopsies from patients with assumed benign IgAN can differentiate between future progressors and non-progressors at the time of diagnosis.
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Affiliation(s)
- Mariell Rivedal
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Håvard Mikkelsen
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Hans-Peter Marti
- Department of Clinical Medicine, University of Bergen, Bergen, Norway; Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Lili Liu
- Department of Medicine, Vagelos College of Physicians & Surgeons, Columbia University, New York, New York, USA
| | - Krzysztof Kiryluk
- Department of Medicine, Vagelos College of Physicians & Surgeons, Columbia University, New York, New York, USA; Institute for Genomic Medicine, Columbia University, New York, New York, USA
| | - Thomas Knoop
- Department of Clinical Medicine, University of Bergen, Bergen, Norway; Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Rune Bjørneklett
- Department of Clinical Medicine, University of Bergen, Bergen, Norway; Emergency Care Clinic, Haukeland University Hospital, Bergen, Norway
| | - Yngvar Lunde Haaskjold
- Department of Clinical Medicine, University of Bergen, Bergen, Norway; Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Jessica Furriol
- Department of Clinical Medicine, University of Bergen, Bergen, Norway; Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Sabine Leh
- Department of Pathology, Haukeland University Hospital, Bergen, Norway
| | - Flavia Paunas
- Department of Medicine, Haugesund Hospital, Haugesund, Norway
| | - Janka Bábíčková
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Andreas Scherer
- Spheromics, Kontiolahti, Finland; Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland
| | - Camille Serre
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Oystein Eikrem
- Department of Clinical Medicine, University of Bergen, Bergen, Norway; Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Philipp Strauss
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.
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19
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Girndt M. [Immunoglobulin A nephropathy-New treatment possibilities]. INNERE MEDIZIN (HEIDELBERG, GERMANY) 2024; 65:407-413. [PMID: 38294502 DOI: 10.1007/s00108-024-01665-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/05/2024] [Indexed: 02/01/2024]
Abstract
Immunoglobulin A (IgA) nephropathy is the most frequent glomerulonephritis in adults in Central Europe. It is characterized by microhematuria and occasionally macrohematuria, proteinuria and a chronic loss of kidney function. The diagnosis is made based on a kidney biopsy. The progressive kidney damage must always be slowed down by normalizing blood pressure, using angiotensin inhibitors and consistently avoiding additional toxic substances. In many cases this is not sufficient and then sodium-glucose transporter 2 (SGLT-2) inhibitors and immunomodulators are used. In particular, the SGLT-2 inhibitors show a very significant reduction in proteinuria and slow down the deterioration of the estimated glomerular filtration rate (eGFR). While systemic corticosteroids are now only indicated in rare cases, a special budesonide formulation shows good effects. Further pathophysiologically based pharmacotherapies are currently being tested in clinical studies. These include, among others, the dual endothelin type A receptor and angiotensin II receptor antagonist sparsentan, which has already been shown to reduce proteinuria as well as inhibitors of complement activation, which is important for kidney damage. Initial findings for these as well as for the B‑lymphocyte proliferation inhibitor sibeprenlimab, suggest that they could enrich the armamentarium for the treatment of IgA nephropathy in the future.
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Affiliation(s)
- Matthias Girndt
- Klinik für Innere Medizin II, Martin-Luther-Universität Halle-Wittenberg, Ernst-Grube-Str. 40, 06120, Halle (Saale), Deutschland.
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20
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Ma J, Xing J, Zhang Y, Liu G. Efficacy and safety of biologic agents for IgA nephropathy: A protocol for systematic review and meta-analysis. PLoS One 2024; 19:e0298732. [PMID: 38547115 PMCID: PMC10977724 DOI: 10.1371/journal.pone.0298732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 01/29/2024] [Indexed: 04/02/2024] Open
Abstract
BACKGROUND IgA nephropathy (IgAN) is the most prevalent primary glomerulonephritis worldwide and a leading cause of chronic kidney failure. There are currently no definitive therapeutic regimens to treat or prevent the progression of IgAN. However, biologic agents offer novel therapeutic approaches that target immunological mechanisms to slow or halt disease progression. The objective of this study is to evaluate the efficacy and safety of biologic agents in patients with IgA nephropathy. METHODS We will systematically search PubMed, EMbase, Web of Science, Cochrane Library, and www.clinicaltrials.gov for randomized controlled trials of biologic agents for the treatment of IgA nephropathy. The search period will span from the establishment of each database until October 2023. The quality assessment of included studies will be performed individually using the revised Cochrane risk-of-bias tool for randomized trials (RoB 2), and meta-analysis will be conducted using Revman 5.4.1 software. CONCLUSIONS The results of this study will provide evidence-based medical evidence for the clinical application of biologic agents in patients with IgA nephropathy. PROSPERO REGISTRATION NUMBER CRD42023400450.
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Affiliation(s)
- Jia Ma
- Shanxi Traditional Chinese Medical Hospital, Taiyuan, China
- Shanxi University of Chinese Medicine, Taiyuan, China
| | - Jianyue Xing
- Shanxi Traditional Chinese Medical Hospital, Taiyuan, China
| | - Yupeng Zhang
- Shanxi Traditional Chinese Medical Hospital, Taiyuan, China
| | - Guangzhen Liu
- Shanxi Traditional Chinese Medical Hospital, Taiyuan, China
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21
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Gaumond L, Lamarche C, Beauchemin S, Henley N, Elftouh N, Gerarduzzi C, Laurin LP. Identification of inflammatory biomarkers in IgA nephropathy using the NanoString technology: a validation study in Caucasians. Inflamm Res 2024; 73:447-457. [PMID: 38291238 PMCID: PMC10894174 DOI: 10.1007/s00011-023-01848-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/16/2023] [Accepted: 12/27/2023] [Indexed: 02/01/2024] Open
Abstract
OBJECTIVE AND DESIGN Immunoglobulin A nephropathy (IgAN) is a kidney disease characterized by the accumulation of IgA deposits in the glomeruli of the kidney, leading to inflammation and damage to the kidney. The inflammatory markers involved in IgAN remain to be defined. Gene expression analysis platforms, such as the NanoString nCounter system, are promising screening and diagnostic tools, especially in oncology. Still, their role as a diagnostic and prognostic tool in IgAN remains scarce. In this study, we aimed to validate the use of NanoString technology to identify potential inflammatory biomarkers involved in the progression of IgAN. SUBJECTS A total of 30 patients with biopsy-proven IgAN and 7 cases of antineutrophil cytoplasmic antibody (ANCA)-associated pauci-immune glomerulonephritis were included for gene expression measurement. For the immunofluorescence validation experiments, a total of 6 IgAN patients and 3 controls were included. METHODS Total RNA was extracted from formalin-fixed paraffin-embedded kidney biopsy specimens, and a customized 48-plex human gene CodeSet was used to study 29 genes implicated in different biological pathways. Comparisons in gene expression were made between IgAN and ANCA-associated pauci-immune glomerulonephritis patients to delineate an expression profile specific to IgAN. Gene expression was compared between patients with low and moderate risk of progression. Genes for which RNA expression was associated with disease progression were analyzed for protein expression by immunofluorescence and compared with controls. RESULTS IgAN patients had a distinct gene expression profile with decreased expression in genes IL-6, INFG, and C1QB compared to ANCA patients. C3 and TNFRSF1B were identified as potential biomarkers for IgAN progression in patients early in their disease course. Protein expression for those 2 candidate genes was upregulated in IgAN patients compared to controls. Expression of genes implicated in fibrosis (PTEN, CASPASE 3, TGM2, TGFB1, IL2, and TNFRSF1B) was more pronounced in IgAN patients with severe fibrosis compared to those with none. CONCLUSIONS Our findings validate our NanoString mRNA profiling by examining protein expression levels of two candidate genes, C3 and TNFRSF1B, in IgAN patients and controls. We also identified several upregulated mRNA transcripts implicated in the development of fibrosis that may be considered fibrotic markers within IgAN patients.
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Affiliation(s)
- Laurence Gaumond
- Division of Nephrology, Maisonneuve-Rosemont Hospital, 5415 Boulevard de l'Assomption, Montreal, QC, H1T 2M4, Canada
| | - Caroline Lamarche
- Division of Nephrology, Maisonneuve-Rosemont Hospital, 5415 Boulevard de l'Assomption, Montreal, QC, H1T 2M4, Canada
- Research Center, Maisonneuve-Rosemont Hospital, Montreal, QC, Canada
- Department of Medicine, University of Montreal, Montreal, QC, Canada
| | | | - Nathalie Henley
- Research Center, Maisonneuve-Rosemont Hospital, Montreal, QC, Canada
| | - Naoual Elftouh
- Research Center, Maisonneuve-Rosemont Hospital, Montreal, QC, Canada
| | - Casimiro Gerarduzzi
- Research Center, Maisonneuve-Rosemont Hospital, Montreal, QC, Canada.
- Department of Medicine, University of Montreal, Montreal, QC, Canada.
| | - Louis-Philippe Laurin
- Division of Nephrology, Maisonneuve-Rosemont Hospital, 5415 Boulevard de l'Assomption, Montreal, QC, H1T 2M4, Canada.
- Research Center, Maisonneuve-Rosemont Hospital, Montreal, QC, Canada.
- Department of Medicine, University of Montreal, Montreal, QC, Canada.
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22
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Lim RS, Yeo SC, Barratt J, Rizk DV. An Update on Current Therapeutic Options in IgA Nephropathy. J Clin Med 2024; 13:947. [PMID: 38398259 PMCID: PMC10889409 DOI: 10.3390/jcm13040947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 01/30/2024] [Accepted: 02/04/2024] [Indexed: 02/25/2024] Open
Abstract
Immunoglobulin A nephropathy (IgAN) remains the leading cause of primary glomerular disease worldwide. Outcomes are poor with high rates of progressive chronic kidney disease and kidney failure, which contributes to global healthcare costs. Although this disease entity has been described, there were no disease-specific treatments until recently, with the current standard of care focusing on optimal supportive measures including lifestyle modifications and optimization of the renin-angiotensin-aldosterone blockade. However, with significant advances in the understanding of the pathogenesis of IgAN in the past decade, and the acceptance of surrogate outcomes for accelerated drug approval, there have been many new investigational agents tested to target this disease. As these agents become available, we envision a multi-pronged treatment strategy that simultaneously targets the consequences of ongoing nephron loss, stopping any glomerular inflammation, inhibiting pro-fibrotic signals in the glomerulus and tubulo-interstitium, and inhibiting the production of pathogenic IgA molecules. This review is an update on a previous review published in 2021, and we aim to summarize the developments and updates in therapeutic strategies in IgAN and highlight the promising discoveries that are likely to add to our armamentarium.
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Affiliation(s)
- Regina Shaoying Lim
- Department of Renal Medicine, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore; (R.S.L.); (S.C.Y.)
| | - See Cheng Yeo
- Department of Renal Medicine, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore; (R.S.L.); (S.C.Y.)
| | - Jonathan Barratt
- Department of Cardiovascular Sciences, University of Leicester, Leicester LE1 7RH, UK;
- John Walls Renal Unit, University Hospitals of Leicester NHS Trust, Leicester LE5 4PW, UK
| | - Dana V. Rizk
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, ZRB 614, 1720 2nd Avenue South, Birmingham, AL 35294, USA
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23
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Tunnicliffe DJ, Reid S, Craig JC, Samuels JA, Molony DA, Strippoli GF. Non-immunosuppressive treatment for IgA nephropathy. Cochrane Database Syst Rev 2024; 2:CD003962. [PMID: 38299639 PMCID: PMC10832348 DOI: 10.1002/14651858.cd003962.pub3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
BACKGROUND IgA nephropathy (IgAN) is the most common primary glomerular disease, with approximately 20% to 40% of patients progressing to kidney failure within 25 years. Non-immunosuppressive treatment has become a mainstay in the management of IgAN by improving blood pressure (BP) management, decreasing proteinuria, and avoiding the risks of long-term immunosuppressive management. Due to the slowly progressive nature of the disease, clinical trials are often underpowered, and conflicting information about management with non-immunosuppressive treatment is common. This is an update of a Cochrane review, first published in 2011. OBJECTIVES To assess the benefits and harms of non-immunosuppressive treatment for treating IgAN in adults and children. We aimed to examine all non-immunosuppressive therapies (e.g. anticoagulants, antihypertensives, dietary restriction and supplementation, tonsillectomy, and herbal medicines) in the management of IgAN. SEARCH METHODS We searched the Cochrane Kidney and Transplant Register of Studies up to December 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov. SELECTION CRITERIA Randomised controlled trials (RCTs) and quasi-RCTs of non-immunosuppressive agents in adults and children with biopsy-proven IgAN were included. DATA COLLECTION AND ANALYSIS Two authors independently reviewed search results, extracted data and assessed study quality. Results were expressed as mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI) using random-effects meta-analysis. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. MAIN RESULTS This review includes 80 studies (4856 participants), of which 24 new studies (2018 participants) were included in this review update. The risk of bias within the included studies was mostly high or unclear for many of the assessed methodological domains, with poor reporting of important key clinical trial methods in most studies. Antihypertensive therapies were the most examined non-immunosuppressive therapy (37 studies, 1799 participants). Compared to placebo or no treatment, renin-angiotensin system (RAS) inhibition probably decreases proteinuria (3 studies, 199 participants: MD - 0.71 g/24 h, 95% CI -1.04 to -0.39; moderate certainty evidence) but may result in little or no difference to kidney failure or doubling of serum creatinine (SCr), or complete remission of proteinuria (low certainty evidence). Death, remission of haematuria, relapse of proteinuria or > 50% increase in SCr were not reported. Compared to symptomatic treatment, RAS inhibition (3 studies, 168 participants) probably decreases proteinuria (MD -1.16 g/24 h, 95% CI -1.52 to -0.81) and SCr (MD -9.37 µmol/L, 95% CI -71.95 to -6.80) and probably increases creatinine clearance (2 studies, 127 participants: MD 23.26 mL/min, 95% CI 10.40 to 36.12) (all moderate certainty evidence); however, the risk of kidney failure is uncertain (1 study, 34 participants: RR 0.20, 95% CI 0.01 to 3.88; very low certainty evidence). Death, remission of proteinuria or haematuria, or relapse of proteinuria were not reported. The risk of adverse events may be no different with RAS inhibition compared to either placebo or symptomatic treatment (low certainty evidence). In low certainty evidence, tonsillectomy in people with IgAN in addition to standard care may increase remission of proteinuria compared to standard care alone (2 studies, 143 participants: RR 1.90, 95% CI 1.45 to 2.47) and remission of microscopic haematuria (2 studies, 143 participants: RR 1.93, 95% CI 1.47 to 2.53) and may decrease relapse of proteinuria (1 study, 73 participants: RR 0.70, 95% CI 0.57 to 0.85) and relapse of haematuria (1 study, 72 participants: RR 0.70, 95% CI 0.51 to 0.98). Death, kidney failure and a > 50% increase in SCr were not reported. These trials have only been conducted in Japanese people with IgAN, and the findings' generalisability is unclear. Anticoagulant therapy, fish oil, and traditional Chinese medicines exhibited small benefits to kidney function in patients with IgAN when compared to placebo or no treatment. However, compared to standard care, the kidney function benefits are no longer evident. Antimalarial therapy compared to placebo in one study reported an increase in a > 50% reduction of proteinuria (53 participants: RR 3.13 g/24 h, 95% CI 1.17 to 8.36; low certainty evidence). Although, there was uncertainty regarding adverse events from this study due to very few events. AUTHORS' CONCLUSIONS Available RCTs focused on a diverse range of interventions. They were few, small, and of insufficient duration to determine potential long-term benefits on important kidney and cardiovascular outcomes and harms of treatment. Antihypertensive agents appear to be the most beneficial non-immunosuppressive intervention for IgAN. The antihypertensives examined were predominantly angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. The benefits of RAS inhibition appear to outweigh the harms in patients with IgAN. The certainty of the evidence of RCTs demonstrating a benefit of tonsillectomy to patients with Japanese patients with IgAN was low. In addition, these findings are inconsistent across observational studies in people with IgAN of other ethnicities; hence, tonsillectomy is not widely recommended, given the potential harm of therapy. The RCT evidence is insufficiently robust to demonstrate efficacy for the other non-immunosuppressive treatments evaluated here.
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Affiliation(s)
| | - Sharon Reid
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Jonathan C Craig
- Cochrane Kidney and Transplant, Centre for Kidney Research, The Children's Hospital at Westmead, Westmead, Australia
- College of Medicine and Public Health, Flinders University, Adelaide, Australia
| | - Joshua A Samuels
- Division of Pediatric Nephrology and Hypertension, UT-Houston Health Science Center, Houston, TX, USA
| | - Donald A Molony
- Internal Medicine, UT-Houston Health Science Center, Houston, TX, USA
| | - Giovanni Fm Strippoli
- Cochrane Kidney and Transplant, Centre for Kidney Research, The Children's Hospital at Westmead, Westmead, Australia
- Department of Emergency and Organ Transplantation, University of Bari, Bari, Italy
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24
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Zhang H, Rizk DV, Perkovic V, Maes B, Kashihara N, Rovin B, Trimarchi H, Sprangers B, Meier M, Kollins D, Papachristofi O, Milojevic J, Junge G, Nidamarthy PK, Charney A, Barratt J. Results of a randomized double-blind placebo-controlled Phase 2 study propose iptacopan as an alternative complement pathway inhibitor for IgA nephropathy. Kidney Int 2024; 105:189-199. [PMID: 37914086 DOI: 10.1016/j.kint.2023.09.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 08/30/2023] [Accepted: 09/27/2023] [Indexed: 11/03/2023]
Abstract
Targeting the alternative complement pathway is an attractive therapeutic strategy given its role in the pathogenesis of immunoglobulin A nephropathy (IgAN). Iptacopan (LNP023) is an oral, proximal alternative complement inhibitor that specifically binds to Factor B. Our randomized, double-blind, parallel-group adaptive Phase 2 study (NCT03373461) enrolled patients with biopsy-confirmed IgAN (within previous three years) with estimated glomerular filtration rates of 30 mL/min/1.73 m2 and over and urine protein 0.75 g/24 hours and over on stable doses of renin angiotensin system inhibitors. Patients were randomized to four iptacopan doses (10, 50, 100, or 200 mg bid) or placebo for either a three-month (Part 1; 46 patients) or a six-month (Part 2; 66 patients) treatment period. The primary analysis evaluated the dose-response relationship of iptacopan versus placebo on 24-hour urine protein-to-creatinine ratio (UPCR) at three months. Other efficacy, safety and biomarker parameters were assessed. Baseline characteristics were generally well-balanced across treatment arms. There was a statistically significant dose-response effect, with 23% reduction in UPCR achieved with iptacopan 200 mg bid (80% confidence interval 8-34%) at three months. UPCR decreased further through six months in iptacopan 100 and 200 mg arms (from a mean of 1.3 g/g at baseline to 0.8 g/g at six months in the 200 mg arm). A sustained reduction in complement biomarker levels including plasma Bb, serum Wieslab, and urinary C5b-9 was observed. Iptacopan was well-tolerated, with no reports of deaths, treatment-related serious adverse events or bacterial infections, and led to strong inhibition of alternative complement pathway activity and persistent proteinuria reduction in patients with IgAN. Thus, our findings support further evaluation of iptacopan in the ongoing Phase 3 trial (APPLAUSE-IgAN; NCT04578834).
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Affiliation(s)
- Hong Zhang
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, People's Republic of China.
| | - Dana V Rizk
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Vlado Perkovic
- University of New South Wales, Sydney, New South Wales, Australia
| | - Bart Maes
- Department of Nephrology, AZ Delta, Roeselare, Belgium
| | - Naoki Kashihara
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Japan
| | - Brad Rovin
- Division of Nephrology, the Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Hernán Trimarchi
- Nephrology Service and Kidney Transplantation Unit, Hospital Británico de Buenos Aires, Buenos Aires, Argentina
| | - Ben Sprangers
- Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium; Department of Nephrology, University Hospitals Leuven, Leuven, Belgium
| | | | | | | | - Julie Milojevic
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Guido Junge
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Alan Charney
- Novartis Pharmaceuticals Corporation, East Hanover, New Jersey, USA
| | - Jonathan Barratt
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK; The John Walls Renal Unit, University Hospitals of Leicester NHS Trust, Leicester, UK
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25
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Zheng J, Li G, Liu W, Deng Y, Xu X. The Expression of Non B Cell-Derived Immunoglobulins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1445:11-36. [PMID: 38967747 DOI: 10.1007/978-981-97-0511-5_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/06/2024]
Abstract
Although V(D)J recombination and immunoglobulin (Ig) production are traditionally recognised to occur only in B lymphocytes and plasma cells, the expression of Igs in non-lymphoid cells, which we call non B cell-derived Igs (non B Igs), has been documented by growing studies. It has been demonstrated that non B-Igs can be widely expressed in most cell types, including, but not limited to, epithelial cells, cardiomyocytes, hematopoietic stem/progenitor cells, myeloid cells, and cells from immune-privileged sites, such as neurons and spermatogenic cells. In particular, malignant tumour cells express high level of IgG. Moreover, different from B-Igs that mainly localised on the B cell membrane and in the serum and perform immune defence function mainly, non B-Igs have been found to distribute more widely and play critical roles in immune defence, maintaining cell proliferation and survival, and promoting progression. The findings of non B-Igs may provide a wealthier breakthrough point for more therapeutic strategies for a wide range of immune-related diseases.
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Affiliation(s)
- Jie Zheng
- Hematologic Disease Laboratory, Department of Stem Cell Transplantation, Beijing Children's Hospital, Capital Medical University, Beijing, China.
| | - Guohui Li
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Wei Liu
- Department of Immunology, Hebei Medical University, Shijiazhuang, China
| | - Yuqing Deng
- Department of Immunology, Hebei Medical University, Shijiazhuang, China
| | - XiaoJun Xu
- Department of Immunology, School of Basic Medical Sciences, Peking University, Beijing, China
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26
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Caravaca-Fontán F, Gutiérrez E, Sevillano ÁM, Praga M. Targeting complement in IgA nephropathy. Clin Kidney J 2023; 16:ii28-ii39. [PMID: 38053977 PMCID: PMC10695513 DOI: 10.1093/ckj/sfad198] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Indexed: 12/07/2023] Open
Abstract
Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. Recent years have witnessed significant improvements in the understanding of the pathogenesis of IgAN and particularly, the pathogenic role of complement activation. The alternative complement pathway is the major complement cascade activator in IgAN, and glomerular C3 deposition has been shown to correlate with disease progression. In addition, several studies have provided insight into the pathogenic role of factor H-related proteins -1 and -5 in IgAN, as independent players in complement dysregulation. The lectin pathway has also been shown to be associated with the severity of IgAN. Glomerular deposition of C4d has been associated with increased histologic disease activity, faster decline in estimated glomerular filtration rate and higher risk of kidney failure. On the other hand, although overlooked in the Oxford classification, numerous studies have shown that the coexistence of thrombotic microangiopathy in IgAN is a significant indicator of a poorer prognosis. All the breakthroughs in the understanding of the contributing role of complement in IgAN have paved the way for the development of new complement-targeted therapies in this disease. Several ongoing trials are evaluating the efficacy of new agents against factor B (iptacopan, Ionis-FB-LRX), C3 (pegcetacoplan), factor D (vemircopan, pelecopan), C5 (ravulizumab, cemdisiran) and C5a receptor 1 (avacopan). In this study, we provide a comprehensive review of the role of complement in IgAN, including the emerging mechanisms of complement activation and the promising potential of complement inhibitors as a viable treatment option for IgAN.
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Affiliation(s)
- Fernando Caravaca-Fontán
- Department of Nephrology, Instituto de Investigación Hospital 12 de Octubre (imas12), Madrid, Spain
| | - Eduardo Gutiérrez
- Department of Nephrology, Hospital Universitario 12 de Octubre (imas12), Madrid, Spain
| | - Ángel M Sevillano
- Department of Nephrology, Hospital Universitario 12 de Octubre (imas12), Madrid, Spain
| | - Manuel Praga
- Department of Nephrology, Instituto de Investigación Hospital 12 de Octubre (imas12), Madrid, Spain
- Department of Medicine, Complutense University, Madrid, Spain
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Rizk DV, Novak L, Hall SD, Moldoveanu Z, Julian BA, Novak J, Haas M. Colocalization of IgG and IgA Heavy Chains with Kappa and Lambda Light Chains in Glomerular Deposits of IgA Nephropathy Patients Using High-Resolution Confocal Microscopy and Correlation with Oxford MEST-C Scores. J Clin Med 2023; 12:7361. [PMID: 38068413 PMCID: PMC10707091 DOI: 10.3390/jcm12237361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/20/2023] [Accepted: 11/23/2023] [Indexed: 02/12/2024] Open
Abstract
Routine immunofluorescence microscopy of glomerular immunodeposits in IgA nephropathy shows IgA, C3, and lambda light chains, and sometimes IgG, IgM, and kappa light chains. However, a previous study using high-resolution confocal microscopy showed IgG in all IgA nephropathy cases, likely representing autoantibodies specific for galactose-deficient IgA1. Here, we used high-resolution confocal microscopy to examine the composition of glomerular immunodeposits and colocalization of kappa and lambda light chains with IgA or IgG heavy chains in kidney-biopsy samples from twenty patients with IgA nephropathy, seventeen without IgG, and nine with no or trace kappa light chains by routine immunofluorescence microscopy. IgG was detected in all biopsies by high-resolution confocal microscopy. Single-optical-plane images showed similar colocalization of IgG heavy chains with kappa and lambda light chains. Colocalization of IgA heavy chains was greater with lambda light chains than with kappa light chains. Colocalization of IgG heavy chain with kappa light chains was higher than with lambda light chains in biopsies with endocapillary hypercellularity and crescents, i.e., biopsies with active lesions. We confirmed the utility of high-resolution confocal microscopy to detect components of glomerular immunodeposits not apparent on routine immunofluorescence microscopy and for colocalization of different components, potentially clarifying the pathogenesis of IgA nephropathy.
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Affiliation(s)
- Dana V. Rizk
- Department of Medicine, Division of Nephrology, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
| | - Lea Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (L.N.); (S.D.H.); (Z.M.); (J.N.)
| | - Stacy D. Hall
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (L.N.); (S.D.H.); (Z.M.); (J.N.)
| | - Zina Moldoveanu
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (L.N.); (S.D.H.); (Z.M.); (J.N.)
| | - Bruce A. Julian
- Department of Medicine, Division of Nephrology, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (L.N.); (S.D.H.); (Z.M.); (J.N.)
| | - Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (L.N.); (S.D.H.); (Z.M.); (J.N.)
| | - Mark Haas
- Department of Pathology & Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA;
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Ștefan G, Jullien P, Masson I, Alamartine E, Mariat C, Maillard N. Circulating alternative pathway complement cleavage factor Bb is associated with vascular lesions and outcomes in IgA nephropathy. Nephrol Dial Transplant 2023; 38:ii11-ii18. [PMID: 37816675 DOI: 10.1093/ndt/gfad163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Indexed: 10/12/2023] Open
Abstract
BACKGROUND Complement alternative pathway (AP) activation is linked to immunoglobulin A nephropathy (IgAN) prognosis severity, but Bb fragment's role is unclear. We examined the relationship between serum Bb fragment concentration at IgAN diagnosis and disease activity and outcomes. METHODS This retrospective study included 125 biopsy-proven IgAN patients [age 39.9 years, 75% male, estimated glomerular filtration rate (eGFR) 82 ml/min, proteinuria 0.5 g/day] enrolled from 1984 to 2010 and followed for a minimum of 18 months. Monitoring continued until the last follow-up, end-stage kidney disease (ESKD) or death. Serum Bb fragment was measured using an enzyme-linked immunosorbent assay at diagnosis. Oxford classification and global optical score (GOS) were utilized for pathology assessment. RESULTS Patients were followed for a median of 16 years; 42% developed chronic kidney disease stage ≥3, 19% reached ESKD and 9% died. Serum Bb fragment concentration negatively correlated with eGFR values at the last follow-up and positively with vascular and tubular histopathological indices. In univariate Cox regression analyses, higher Bb fragment concentration was associated with ESKD alongside older age, increased body mass index, arterial hypertension, lower eGFR, higher proteinuria, E1, S1, T1-2, GOS and corticotherapy. Patients with Bb levels ≥14.3 μg/ml had shorter mean kidney survival time (19.5 versus 22.7 years, P = .07); after adjusting for progression risk factors, the association persisted [hazard ratio 4.76 (95% confidence interval 1.56-14.43)]. CONCLUSIONS Serum Bb fragment concentration at diagnosis may predict long-term IgAN outcomes, potentially due to AP activation at the endothelial surface. Further research is needed to confirm these results and evaluate Bb fragment's role in IgAN management.
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Affiliation(s)
- Gabriel Ștefan
- Service de Néphrologie, Hôpital Nord CHU Saint Etienne, Saint Etienne, France
- University of Medicine and Pharmacy "Carol Davila", Nephrology Department, Bucharest, Romania
| | - Perrine Jullien
- Service de Néphrologie, Hôpital Nord CHU Saint Etienne, Saint Etienne, France
- Groupe Immunité muqueuse et agents pathogènes (GIMAP, team 15 CIRI INSERM U1111/UMR5108), Saint Etienne, France
| | - Ingrid Masson
- Service de Néphrologie, Hôpital Nord CHU Saint Etienne, Saint Etienne, France
- Groupe Immunité muqueuse et agents pathogènes (GIMAP, team 15 CIRI INSERM U1111/UMR5108), Saint Etienne, France
| | - Eric Alamartine
- Service de Néphrologie, Hôpital Nord CHU Saint Etienne, Saint Etienne, France
- Groupe Immunité muqueuse et agents pathogènes (GIMAP, team 15 CIRI INSERM U1111/UMR5108), Saint Etienne, France
| | - Christophe Mariat
- Service de Néphrologie, Hôpital Nord CHU Saint Etienne, Saint Etienne, France
- Groupe Immunité muqueuse et agents pathogènes (GIMAP, team 15 CIRI INSERM U1111/UMR5108), Saint Etienne, France
| | - Nicolas Maillard
- Service de Néphrologie, Hôpital Nord CHU Saint Etienne, Saint Etienne, France
- Groupe Immunité muqueuse et agents pathogènes (GIMAP, team 15 CIRI INSERM U1111/UMR5108), Saint Etienne, France
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Terinte-Balcan G, Stancu S, Zugravu A, Capusa C, Radu A, Mircescu G, Stefan G. Prognostic role of glomerular electron microscopy lesions in IgA nephropathy: "the devil is in the details". J Nephrol 2023; 36:2233-2243. [PMID: 37632668 DOI: 10.1007/s40620-023-01744-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 07/28/2023] [Indexed: 08/28/2023]
Abstract
INTRODUCTION Transmission electron microscopy enables examination of ultrastructural glomerular changes; while this tool has already been applied in IgA nephropathy (IgAN), limited information exists on the prognostic value in this disease. We aimed to systematically investigate ultrastructural lesions and assess their role in predicting the evolution of IgA nephropathy to end-stage kidney disease. METHODS A single-center retrospective study was performed on 107 consecutive IgAN patients (median age 42 years, 67% male, estimated glomerular filtration rate 46 mL/min, proteinuria 1.0 g/g) between 2010 and 2015, who were followed-up until end-stage kidney disease, death, or end of study (January 2021). A pathologist evaluated the Mesangial hypercellularity (M), Endocapillary hypercellularity (E), Segmental glomerulosclerosis (S), and Tubular atrophy/interstitial fibrosis-Crescents (C) (MEST-C) score and transmission electron microscopy lesions according to a comprehensive protocol that encompassed all glomerular structures. RESULTS Patients were followed up for a median of 7.1 years; 32 (43%) reached end-stage kidney disease. Patients who reached kidney failure had higher comorbidity score, more frequent arterial hypertension, lower estimated glomerular filtration rate, and higher MEST-C score. In terms of transmission electron microscopy lesions, patients who progressed to end-stage kidney disease had more frequent podocyte activation, effacement, and presence of microvilli; more frequent signs of endothelial cell activation and fenestration; higher mesangial cell proliferation. In the univariate Cox proportional hazard regression, higher MEST-C score and lesions detected by transmission electron microscopy in podocytes, endothelial cells, and mesangial cell proliferation were associated with shorter kidney survival time. In the multivariate Cox proportional hazard regression, only higher MEST-C score, presence of podocytes with microvilli, and mesangial cell proliferation were associated with end-stage kidney disease. CONCLUSION This study shows that, besides the MEST-C score, the presence of podocytes with microvilli and mesangial cell proliferation are associated with poor kidney survival in IgAN patients, highlighting the prognostic value of lesions detected by transmission electron microscopy.
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Affiliation(s)
- George Terinte-Balcan
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
- Ultrastructural Pathology Laboratory, "Victor Babes" National Institute of Pathology, Bucharest, Romania
| | - Simona Stancu
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
- "Dr. Carol Davila" Teaching Hospital of Nephrology, Bucharest, Romania
| | - Adrian Zugravu
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
- "Dr. Carol Davila" Teaching Hospital of Nephrology, Bucharest, Romania
| | - Cristina Capusa
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
- "Dr. Carol Davila" Teaching Hospital of Nephrology, Bucharest, Romania
| | - Andreea Radu
- "Dr. Carol Davila" Teaching Hospital of Nephrology, Bucharest, Romania
| | - Gabriel Mircescu
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
- "Dr. Carol Davila" Teaching Hospital of Nephrology, Bucharest, Romania
| | - Gabriel Stefan
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania.
- "Dr. Carol Davila" Teaching Hospital of Nephrology, Bucharest, Romania.
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Kohan DE, Barratt J, Heerspink HJ, Campbell KN, Camargo M, Ogbaa I, Haile-Meskale R, Rizk DV, King A. Targeting the Endothelin A Receptor in IgA Nephropathy. Kidney Int Rep 2023; 8:2198-2210. [PMID: 38025243 PMCID: PMC10658204 DOI: 10.1016/j.ekir.2023.07.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/09/2023] [Accepted: 07/24/2023] [Indexed: 12/01/2023] Open
Abstract
Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide and carries a substantial risk of kidney failure. New agency-approved therapies, either specifically for IgAN or for chronic kidney disease (CKD) in general, hold out hope for mitigating renal deterioration in patients with IgAN. The latest addition to this therapeutic armamentarium targets the endothelin-A receptor (ETAR). Activation of ETAR on multiple renal cell types elicits a host of pathophysiological effects, including vasoconstriction, cell proliferation, inflammation, apoptosis, and fibrosis. Blockade of ETAR is renoprotective in experimental models of IgAN and reduces proteinuria in patients with IgAN. This review discusses the evidence supporting the use of ETAR blockade in IgAN as well as addressing the potential role for this class of agents among the current and emerging therapies for treating this disorder.
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Affiliation(s)
- Donald E. Kohan
- Division of Nephrology, University of Utah Health, Salt Lake City, Utah, USA
| | - Jonathan Barratt
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Hiddo J.L. Heerspink
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Kirk N. Campbell
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | | | - Ike Ogbaa
- Chinook Therapeutics, Seattle, Washington, USA
| | | | - Dana V. Rizk
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Andrew King
- Chinook Therapeutics, Seattle, Washington, USA
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31
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Rajasekaran A, Green TJ, Renfrow MB, Julian BA, Novak J, Rizk DV. Current Understanding of Complement Proteins as Therapeutic Targets for the Treatment of Immunoglobulin A Nephropathy. Drugs 2023; 83:1475-1499. [PMID: 37747686 PMCID: PMC10807511 DOI: 10.1007/s40265-023-01940-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2023] [Indexed: 09/26/2023]
Abstract
Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide and a frequent cause of kidney failure. Currently, the diagnosis necessitates a kidney biopsy, with routine immunofluorescence microscopy revealing IgA as the dominant or co-dominant immunoglobulin in the glomerular immuno-deposits, often with IgG and sometimes IgM or both. Complement protein C3 is observed in most cases. IgAN leads to kidney failure in 20-40% of patients within 20 years of diagnosis and reduces average life expectancy by about 10 years. There is increasing clinical, biochemical, and genetic evidence that the complement system plays a paramount role in the pathogenesis of IgAN. The presence of C3 in the kidney immuno-deposits differentiates the diagnosis of IgAN from subclinical glomerular mesangial IgA deposition. Markers of complement activation via the lectin and alternative pathways in kidney-biopsy specimens are associated with disease activity and are predictive of poor outcome. Levels of select complement proteins in the circulation have also been assessed in patients with IgAN and found to be of prognostic value. Ongoing genetic studies have identified at least 30 loci associated with IgAN. Genes within some of these loci encode complement-system regulating proteins that can interact with immune complexes. The growing appreciation for the central role of complement components in IgAN pathogenesis highlighted these pathways as potential treatment targets and sparked great interest in pharmacological agents targeting the complement cascade for the treatment of IgAN, as evidenced by the plethora of ongoing clinical trials.
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Affiliation(s)
- Arun Rajasekaran
- Division of Nephrology, Department of Medicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Todd J Green
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Matthew B Renfrow
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Bruce A Julian
- Division of Nephrology, Department of Medicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jan Novak
- Department of Microbiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Dana V Rizk
- Division of Nephrology, Department of Medicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
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Bednarova K, Mjøen G, Hruba P, Modos I, Voska L, Kollar M, Viklicky O. A novel prognostic nomogram predicts premature failure of kidney allografts with IgA nephropathy recurrence. Nephrol Dial Transplant 2023; 38:2627-2636. [PMID: 37202220 PMCID: PMC10660147 DOI: 10.1093/ndt/gfad097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Indexed: 05/20/2023] Open
Abstract
BACKGROUND Recurrence of immunoglobulin A nephropathy (IgAN) limits graft survival in kidney transplantation. However, predictors of a worse outcome are poorly understood. METHODS Among 442 kidney transplant recipients (KTRs) with IgAN, 83 (18.8%) KTRs exhibited biopsy-proven IgAN recurrence between 1994 and 2020 and were enrolled in the derivation cohort. A multivariable Cox model predicting allograft loss based on clinical data at the biopsy and a web-based nomogram were developed. The nomogram was externally validated using an independent cohort (n = 67). RESULTS Patient age <43 years {hazard ratio [HR] 2.20 [95% confidence interval (CI) 1.41-3.43], P < .001}, female gender [HR 1.72 (95% CI 1.07-2.76), P = .026] and retransplantation status [HR 1.98 (95% CI 1.13-3.36), P = .016] were identified as independent risk factors for IgAN recurrence. Patient age <43 years [HR 2.77 (95% CI 1.17-6.56), P = .02], proteinuria >1 g/24 hours [HR 3.12 (95% CI 1.40-6.91), P = .005] and C4d positivity [HR 2.93 (95% CI 1.26-6.83), P = .013] were found to be associated with graft loss in patients with IgAN recurrence. A nomogram predicting graft loss was constructed based on clinical and histological variables, with a C statistic of 0.736 for the derivation cohort and 0.807 for the external validation cohort. CONCLUSIONS The established nomogram identified patients with recurrent IgAN at risk for premature graft loss with good predictive performance.
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Affiliation(s)
- Kamila Bednarova
- Department of Nephrology, Transplant Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
- 1st Medical Faculty, Charles University, Prague, Czech Republic
| | - Geir Mjøen
- Department of Nephrology, Oslo University Hospital, Oslo, Norway
| | - Petra Hruba
- Transplant Laboratory, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Istvan Modos
- Department of Informatics, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Ludek Voska
- Clinical and Transplant Pathology Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Marek Kollar
- Clinical and Transplant Pathology Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Ondrej Viklicky
- Department of Nephrology, Transplant Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
- Transplant Laboratory, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
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Boi R, Ebefors K, Nyström J. The role of the mesangium in glomerular function. Acta Physiol (Oxf) 2023; 239:e14045. [PMID: 37658606 DOI: 10.1111/apha.14045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/12/2023] [Accepted: 08/01/2023] [Indexed: 09/03/2023]
Abstract
When discussing glomerular function, one cell type is often left out, the mesangial cell (MC), probably since it is not a part of the filtration barrier per se. The MCs are instead found between the glomerular capillaries, embedded in their mesangial matrix. They are in direct contact with the endothelial cells and in close contact with the podocytes and together they form the glomerulus. The MCs can produce and react to a multitude of growth factors, cytokines, and other signaling molecules and are in the perfect position to be a central hub for crosstalk communication between the cells in the glomerulus. In certain glomerular diseases, for example, in diabetic kidney disease or IgA nephropathy, the MCs become activated resulting in mesangial expansion. The expansion is normally due to matrix expansion in combination with either proliferation or hypertrophy. With time, this expansion can lead to fibrosis and decreased glomerular function. In addition, signs of complement activation are often seen in biopsies from patients with glomerular disease affecting the mesangium. This review aims to give a better understanding of the MCs in health and disease and their role in glomerular crosstalk and inflammation.
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Affiliation(s)
- Roberto Boi
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Kerstin Ebefors
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Jenny Nyström
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Song J, Ke B, Tu W, Fang X. Roles of interferon regulatory factor 4 in the AKI-CKD transition, glomerular diseases and kidney allograft rejection. Ren Fail 2023; 45:2259228. [PMID: 37755331 PMCID: PMC10538460 DOI: 10.1080/0886022x.2023.2259228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/11/2023] [Indexed: 09/28/2023] Open
Abstract
Interferon regulatory factor 4 (IRF4) is expressed in immune cells and is a member of the interferon regulatory factor family. Recently, it has been found that IRF4 plays important roles in the acute kidney injury (AKI)-chronic kidney disease (CKD) transition, glomerular diseases and kidney allograft rejection. In particular, the relationship between IRF4 and the AKI-CKD transition has attracted widespread attention. Furthermore, it was also found that the deficiency of IRF4 hindered the transition from AKI to CKD through the suppression of macrophage-to-fibroblast conversion, inhibition of M1-M2 macrophage polarization, and reduction in neutrophil inward flow. Additionally, an examination of the crucial role of IRF4 in glomerular disease was conducted. It was reported that inhibiting IRF4 could alleviate the progression of glomerular disease, and potential physiopathology mechanisms associated with IRF4 were postulated. Lastly, IRF4 was found to have detrimental effects on the development of antibody-mediated rejection (ABMR) and T-cell-mediated rejection (TCMR).
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Affiliation(s)
- Jianling Song
- Department of Nephrology, The Second Affiliated Hospital of Nanchang University, Nanchang of Jiangxi, P.R. China
| | - Ben Ke
- Department of Nephrology, The Second Affiliated Hospital of Nanchang University, Nanchang of Jiangxi, P.R. China
| | - Weiping Tu
- Department of Nephrology, The Second Affiliated Hospital of Nanchang University, Nanchang of Jiangxi, P.R. China
| | - Xiangdong Fang
- Department of Nephrology, The Second Affiliated Hospital of Nanchang University, Nanchang of Jiangxi, P.R. China
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35
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Keskinyan VS, Lattanza B, Reid-Adam J. Glomerulonephritis. Pediatr Rev 2023; 44:498-512. [PMID: 37653138 DOI: 10.1542/pir.2021-005259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
Glomerulonephritis (GN) encompasses several disorders that cause glomerular inflammation and injury through an interplay of immune-mediated mechanisms, host characteristics, and environmental triggers, such as infections. GN can manifest solely in the kidney or in the setting of a systemic illness, and presentation can range from chronic and relatively asymptomatic hematuria to fulminant renal failure. Classic acute GN is characterized by hematuria, edema, and hypertension, the latter 2 of which are the consequence of sodium and water retention in the setting of renal impairment. Although presenting signs and symptoms and a compatible clinical history can suggest GN, serologic and urinary testing can further refine the differential diagnosis, and renal biopsy can be used for definitive diagnosis. Treatment of GN can include supportive care, renin-angiotensin-aldosterone system blockade, immunomodulatory therapy, and renal transplant. Prognosis is largely dependent on the underlying cause of GN and can vary from a self-limited course to chronic kidney disease. This review focuses on lupus nephritis, IgA nephropathy, IgA vasculitis, and postinfectious GN.
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36
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Tesař V, Radhakrishnan J, Charu V, Barratt J. Challenges in IgA Nephropathy Management: An Era of Complement Inhibition. Kidney Int Rep 2023; 8:1730-1740. [PMID: 37705895 PMCID: PMC10496078 DOI: 10.1016/j.ekir.2023.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/01/2023] [Accepted: 06/12/2023] [Indexed: 09/15/2023] Open
Abstract
IgA nephropathy (IgAN) is the most common glomerular disease worldwide, with an estimated annual incidence of 25 per million adults. Despite optimized supportive care, some patients fail to achieve disease control and suffer progressive deterioration of kidney function. In this subpopulation of patients, the Kidney Disease: Improving Global Outcomes 2021 guidelines recommend consideration of corticosteroids; however, their use is associated with significant side effects. Ongoing clinical trials are expected to identify corticosteroid-sparing therapies to help improve treatment and prognosis for patients with IgAN. It has been well-documented that the complement system plays a significant role in IgAN pathogenesis, and several complement inhibitors are now entering late-stage clinical development. This review evaluates what we know about the role of complement in the pathophysiology of IgAN and considers how the availability of targeted complement inhibitors may impact future clinical practice. Key knowledge gaps are evaluated, and research opportunities are recommended to help guide clinical decision-making and optimize patient outcomes. Such gaps include evaluating the relative contribution of the alternative and lectin pathways to disease pathogenesis, and the importance of determining the dominant pathway driving IgAN progression. Continued research into the staining of complement proteins in kidney biopsies and identifying targeted biomarkers to assess disease progression and treatment responses will also be needed to support the implementation of newer therapies in clinical practice. Considering the future horizons for enhancing the care of patients with IgAN, tackling the outstanding challenges now will help prepare for the best possible future outcomes.
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Affiliation(s)
- Vladimir Tesař
- Department of Nephrology, Charles University, Prague, Czech Republic
| | | | - Vivek Charu
- Department of Pathology, Stanford University, Palo Alto, California, USA
| | - Jonathan Barratt
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
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37
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Cheung CK, Dormer JP, Barratt J. The role of complement in glomerulonephritis-are novel therapies ready for prime time? Nephrol Dial Transplant 2023; 38:1789-1797. [PMID: 36307926 DOI: 10.1093/ndt/gfac296] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Indexed: 08/01/2023] Open
Abstract
The complement system plays a key pathogenic role in glomerular diseases with a diverse range of aetiologies, including C3 glomerulopathy, immunoglobulin A nephropathy, membranous nephropathy, ANCA-associated vasculitis and lupus nephritis. Several novel therapies targeting complement activity have recently been developed, which have now been approved or are in the late stages of clinical development. In this review, potential benefits and challenges of targeting the complement system in glomerular disease are discussed. We summarize current understanding of the role of complement, and the novel targeted therapies that are being developed for the treatment of glomerular disease.
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Affiliation(s)
- Chee Kay Cheung
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- John Walls Renal Unit, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - John P Dormer
- Department of Histopathology, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Jonathan Barratt
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- John Walls Renal Unit, University Hospitals of Leicester NHS Trust, Leicester, UK
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38
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Hayashi A, Kawabe M, Yamamoto I, Ohki Y, Kobayashi A, Ueda H, Tanno Y, Urabe F, Miki J, Yamada H, Kimura T, Okido I, Tsuboi N, Yamamoto H, Yokoo T. Clinical and Pathological Significance of Mesangial C1q Deposition in Kidney Transplant Recipients with Recurrent IgA Nephropathy and Patients with Native IgA Nephropathy. Nephron Clin Pract 2023; 147 Suppl 1:80-88. [PMID: 37339606 DOI: 10.1159/000530916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/22/2023] [Indexed: 06/22/2023] Open
Abstract
INTRODUCTION In kidney transplant recipients (KTRs) whose primary disease is IgA nephropathy (IgAN), IgAN recurrence occurs in approximately half of patients by 5 years postoperatively and is associated with graft survival. Although the alternative and lectin pathways are important in the primary pathogenesis of IgAN, the significance of mesangial C1q deposition, which triggers the classical pathway, is unknown. We investigated the clinicopathological significance of mesangial C1q deposition in both recurrent IgAN in KTRs and native IgAN. METHODS Between 2000 and 2021, we conducted a 1:2 matched case-control study of 18 KTRs diagnosed with recurrent IgAN, with a group of native IgAN patients as the control. We evaluated the rate and presence/absence of mesangial C1q deposition in terms of pathological findings and kidney outcomes in each group. RESULTS The rate of mesangial C1q deposition was significantly higher in the recurrent IgAN patients in KTRs than in native IgAN patients (11/18 [61.1%] vs. 5/36 [13.9%], p = 0.001). In the former group, the incidence of glomerular crescents was relatively higher in C1q-positive patients. There was no significant difference in the annual rate of estimated glomerular filtration rate decline between C1q-positive and C1q-negative patients in either group. CONCLUSION Mesangial C1q deposition was more frequent in KTRs with recurrent IgAN than in patients with native IgAN, but we found no difference in kidney outcomes with respect to mesangial C1q deposition. Further large-scale investigations of the importance of mesangial C1q deposition are needed in both KTRs with recurrent IgAN and patients with native IgAN.
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Affiliation(s)
- Ayaka Hayashi
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Mayuko Kawabe
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Izumi Yamamoto
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan,
| | - Yutaro Ohki
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Akimitsu Kobayashi
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Hiroyuki Ueda
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Yudo Tanno
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Fumihiko Urabe
- Department of Urology, The Jikei University School of Medicine, Tokyo, Japan
| | - Jun Miki
- Department of Urology, The Jikei University School of Medicine, Tokyo, Japan
| | - Hiroki Yamada
- Department of Urology, The Jikei University School of Medicine, Tokyo, Japan
| | - Takahiro Kimura
- Department of Urology, The Jikei University School of Medicine, Tokyo, Japan
| | - Ichiro Okido
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Nobuo Tsuboi
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Hiroyasu Yamamoto
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Takashi Yokoo
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
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Petrou D, Kalogeropoulos P, Liapis G, Lionaki S. IgA Nephropathy: Current Treatment and New Insights. Antibodies (Basel) 2023; 12:40. [PMID: 37366657 DOI: 10.3390/antib12020040] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/23/2023] [Accepted: 06/09/2023] [Indexed: 06/28/2023] Open
Abstract
IgA Nephropathy (IgAN) is the most common cause of primary glomerulonephritis worldwide. Despite the histopathologic hallmark of mesangial IgA deposition, IgAN is a heterogenous autoimmune disease not only in terms of clinical presentation but also in long-term disease progression. The pathogenesis of the disease is complex and includes the generation of circulating IgA immune complexes with chemical and biological characteristics that favor mesangial deposition and reaction to mesangial under-glycosylated IgA1 accumulation, which leads to tissue injury with glomerulosclerosis and interstitial fibrosis. Patients with proteinuria over 1 g, hypertension, and impaired renal function at diagnosis are considered to be at high risk for disease progression and end-stage kidney disease (ESKD). Glucocorticoids have been the mainstay of treatment for these patients for years, but without long-term benefit for renal function and accompanied by several adverse events. A better understanding of the pathophysiology of IgAN in recent years has led to the development of several new therapeutic agents. In this review, we summarize the current therapeutic approach for patients with IgAN as well as all novel investigational agents.
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Affiliation(s)
- Dimitra Petrou
- Department of Nephrology, Second Department of Propaedeutic Internal Medicine, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, 12462 Athens, Greece
| | - Petros Kalogeropoulos
- Department of Nephrology, Second Department of Propaedeutic Internal Medicine, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, 12462 Athens, Greece
| | - George Liapis
- Department of Pathology, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Sophia Lionaki
- Department of Nephrology, Second Department of Propaedeutic Internal Medicine, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, 12462 Athens, Greece
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Wang S, Hu D, Li YQ, Lei Q, Liu L, He X, Han M, Pei G, Zeng R, Xu G. High Renal Mast Cell Density Is Associated with Poor Prognosis in Patients with Immunoglobulin A Nephropathy. Am J Nephrol 2023; 54:106-116. [PMID: 37245508 PMCID: PMC10777718 DOI: 10.1159/000531243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 05/02/2023] [Indexed: 05/30/2023]
Abstract
INTRODUCTION This observational cohort study evaluated the prognostic value of mast cells in the pathogenesis and progression of IgA nephropathy. METHODS A total of 76 adult IgAN patients were enrolled into this study from Jan 2007 and June 2010. Immunohistochemistry and immunofluorescence were used to identify tryptase-positive mast cells in renal biopsy samples. Patients were classified into Tryptasehigh and Tryptaselow groups. Depending on an average of 96-month follow-up, the predictive value of tryptase-positive mast cells in IgAN progression was analyzed. RESULTS Tryptase-positive mast cells were found frequently in IgAN kidneys while rarely observed in normal kidneys. We also found IgAN patients in Tryptasehigh group presented both severe clinical and pathological renal manifestations. Furthermore, Tryptasehigh group contained more interstitial macrophages and lymphocytes infiltration than Tryptaselow group. Higher tryptase-positive cells density is associated with poor prognosis in patients with IgAN. CONCLUSIONS High renal mast cells density is associated with severe renal lesions and poor prognosis in patients with Immunoglobulin A nephropathy. High renal mast cells density might be used as a predictor of poor prognosis in patients with IgAN.
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Affiliation(s)
| | | | | | | | | | | | | | - Guangchang Pei
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rui Zeng
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Gang Xu
- Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Wang S, Dong L, Qin A, Tan J, Zhou X, Qin W. Roles of mesangial C3 and C1q deposition in the clinical manifestations and prognosis of IgAN. Int Immunopharmacol 2023; 120:110354. [PMID: 37235963 DOI: 10.1016/j.intimp.2023.110354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 05/06/2023] [Accepted: 05/14/2023] [Indexed: 05/28/2023]
Abstract
BACKGROUND AND AIM Immunoglobulin A nephropathy (IgAN) is regarded as the most common type of glomerulonephritis around the world and has the potential to result in renal failure. Complement activation has been addressed by a great body of evidence in the pathogenesis of IgAN. We aimed to evaluate the predictive value of C3 and C1q deposition for disease progression in IgAN patients in this retrospective study. METHODS We recruited 1191 biopsy-diagnosed IgAN patients, and they were divided into different groups according to their glomerular immunofluorescence examination of renal biopsy tissues: 1) C3 deposits ≥ 2 + group (N = 518) and C3 deposits < 2 + group (N = 673). 2) C1q deposit-positive group (N = 109) and C1q deposit-negative group (N = 1082). The renal outcomes were end-stage renal disease (ESRD) and/or an estimated glomerular filtration rate (eGFR) decrease greater than 50% from the baseline value. Kaplan-Meier analyses were performed to evaluate renal survival. Univariate and multivariate Cox proportional hazard regression models were used to evaluate the effect of C3 and C1q deposition on renal outcome in IgAN patients. In addition, we compared the predictive value of mesangial C3 and C1q deposition in IgAN patients. RESULTS The median follow-up period was 53 months (interquartile range 36-75 months). During follow-up, 7% (84) of patients progressed to ESRD, and 9% (111) of patients had an eGFR decline ≥ 50%. IgAN patients complicated with C3 deposits ≥ 2 + were associated with more severe renal dysfunction and pathologic lesions at the time of renal biopsy. The crude incidence rates for the endpoint were 12.5% (84 out of 673) and 17.2% (89 out of 518) in the C3 < 2 + and C3 ≥ 2 + groups, respectively (P = 0.022). Of C1q deposit-positive and C1q deposit-negative patients, 22.9% (25 out of 109) and 13.7% (148 out of 1082) reached the composite endpoint, respectively (P = 0.009). Adding C3 deposition to clinical and pathologic models had better predictability of renal disease progression than C1q. CONCLUSION Glomerular C3 and C1q deposits affected the clinicopathologic features of IgAN patients and emerged as independent predictors and risk factors for renal outcomes. In particular, the predictive ability of C3 was slightly better than that of C1q.
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Affiliation(s)
- Siqing Wang
- West China School of Medicine, Sichuan University, Chengdu, Sichuan, China; Division of Nephrology, Department of Medicine, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Lingqiu Dong
- West China School of Medicine, Sichuan University, Chengdu, Sichuan, China; Division of Nephrology, Department of Medicine, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Aiya Qin
- West China School of Medicine, Sichuan University, Chengdu, Sichuan, China; Division of Nephrology, Department of Medicine, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Jiaxing Tan
- West China School of Medicine, Sichuan University, Chengdu, Sichuan, China; Division of Nephrology, Department of Medicine, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Xiaoyuan Zhou
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Wei Qin
- West China School of Medicine, Sichuan University, Chengdu, Sichuan, China; Division of Nephrology, Department of Medicine, West China Hospital of Sichuan University, Chengdu, Sichuan, China.
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Demir S, Yet I, Sardan Ekiz M, Sag E, Bilginer Y, Celikbicak O, Lay I, Ozen S. Plasma Proteomic Analysis Reveals the Potential Role of Lectin and Alternative Complement Pathways in IgA Vasculitis Pathogenesis. Diagnostics (Basel) 2023; 13:diagnostics13101729. [PMID: 37238213 DOI: 10.3390/diagnostics13101729] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 05/08/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
BACKGROUND IgA vasculitis (IgAV) is the most common form of childhood vasculitis. A better understanding of its pathophysiology is required to identify new potential biomarkers and treatment targets. OBJECTIVE to assess the underlying molecular mechanisms in the pathogenesis of IgAV using an untargeted proteomics approach. METHODS Thirty-seven IgAV patients and five healthy controls were enrolled. Plasma samples were collected on the day of diagnosis before any treatment was initiated. We used nano-liquid chromatography-tandem mass spectrometry (nLC-MS/MS) to investigate the alterations in plasma proteomic profiles. For the bioinformatics analyses, databases including Uniprot, PANTHER, KEGG, Reactome, Cytoscape, and IntAct were used. RESULTS Among the 418 proteins identified in the nLC-MS/MS analysis, 20 had significantly different expressions in IgAV patients. Among them, 15 were upregulated and 5 were downregulated. According to the KEGG pathway and function classification analysis, complement and coagulation cascades were the most enriched pathways. GO analyses showed that the differentially expressed proteins were mainly involved in defense/immunity proteins and the metabolite interconversion enzyme family. We also investigated molecular interactions in the identified 20 proteins of IgAV patients. We extracted 493 interactions from the IntAct database for the 20 proteins and used Cytoscape for the network analyses. CONCLUSION Our results clearly suggest the role of the lectin and alternate complement pathways in IgAV. The proteins defined in the pathways of cell adhesion may serve as biomarkers. Further functional studies may lead the way to better understanding of the disease and new therapeutic options for IgAV treatment.
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Affiliation(s)
- Selcan Demir
- Department of Pediatric Rheumatology, Hacettepe University Medical Faculty, 06230 Ankara, Turkey
| | - Idil Yet
- Department of Bioinformatics, Graduate School of Health Sciences, Hacettepe University, 06230 Ankara, Turkey
| | - Melis Sardan Ekiz
- Advanced Technologies Application and Research Center (HUNITEK), Hacettepe University, 06230 Ankara, Turkey
| | - Erdal Sag
- Department of Pediatric Rheumatology, Hacettepe University Medical Faculty, 06230 Ankara, Turkey
| | - Yelda Bilginer
- Department of Pediatric Rheumatology, Hacettepe University Medical Faculty, 06230 Ankara, Turkey
| | - Omur Celikbicak
- Department of Chemistry, Hacettepe University, 06230 Ankara, Turkey
| | - Incilay Lay
- Department of Biochemistry, Hacettepe University Medical Faculty, 06230 Ankara, Turkey
| | - Seza Ozen
- Department of Pediatric Rheumatology, Hacettepe University Medical Faculty, 06230 Ankara, Turkey
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Bruno V, Mühlig AK, Oh J, Licht C. New insights into the immune functions of podocytes: the role of complement. Mol Cell Pediatr 2023; 10:3. [PMID: 37059832 PMCID: PMC10104987 DOI: 10.1186/s40348-023-00157-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 03/24/2023] [Indexed: 04/16/2023] Open
Abstract
Podocytes are differentiated epithelial cells which play an essential role to ensure a normal function of the glomerular filtration barrier (GFB). In addition to their adhesive properties in maintaining the integrity of the filtration barrier, they have other functions, such as synthesis of components of the glomerular basement membrane (GBM), production of vascular endothelial growth factor (VEGF), release of inflammatory proteins, and expression of complement components. They also participate in the glomerular crosstalk through multiple signalling pathways, including endothelin-1, VEGF, transforming growth factor β (TGFβ), bone morphogenetic protein 7 (BMP-7), latent transforming growth factor β-binding protein 1 (LTBP1), and extracellular vesicles.Growing literature suggests that podocytes share many properties of innate and adaptive immunity, supporting a multifunctional role ensuring a healthy glomerulus. As consequence, the "immune podocyte" dysfunction is thought to be involved in the pathogenesis of several glomerular diseases, referred to as "podocytopathies." Multiple factors like mechanical, oxidative, and/or immunologic stressors can induce cell injury. The complement system, as part of both innate and adaptive immunity, can also define podocyte damage by several mechanisms, such as reactive oxygen species (ROS) generation, cytokine production, and endoplasmic reticulum stress, ultimately affecting the integrity of the cytoskeleton, with subsequent podocyte detachment from the GBM and onset of proteinuria.Interestingly, podocytes are found to be both source and target of complement-mediated injury. Podocytes express complement proteins which contribute to local complement activation. At the same time, they rely on several protective mechanisms to escape this damage. Podocytes express complement factor H (CFH), one of the main regulators of the complement cascade, as well as membrane-bound complement regulators like CD46 or membrane cofactor protein (MCP), CD55 or decay-accelerating factor (DAF), and CD59 or defensin. Further mechanisms, like autophagy or actin-based endocytosis, are also involved to ensure podocyte homeostasis and protection against injury.This review will provide an overview of the immune functions of podocytes and their response to immune-mediated injury, focusing on the pathogenic link between complement and podocyte damage.
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Affiliation(s)
- Valentina Bruno
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Paediatrics, University of Toronto, Toronto, ON, Canada
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
| | - Anne Katrin Mühlig
- University Children's Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Department of Pediatric Nephrology, University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jun Oh
- University Children's Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Department of Pediatric Nephrology, University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christoph Licht
- Division of Nephrology, The Hospital for Sick Children, Toronto, ON, Canada.
- Department of Paediatrics, University of Toronto, Toronto, ON, Canada.
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada.
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Kim D, Wong MG. Corticosteroid Therapy in Immunoglobulin A Nephropathy: A Friend or Foe? Kidney Blood Press Res 2023; 48:392-404. [PMID: 36972570 DOI: 10.1159/000530285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 03/13/2023] [Indexed: 03/29/2023] Open
Abstract
BACKGROUND The administration of corticosteroids in addition to supportive care to delay progressive immunoglobulin A nephropathy (IgAN), the most common primary glomerulonephritis worldwide, remains controversial. This is partly due to the paucity of well-designed randomized controlled trials and well-known corticosteroid-related side effects. As a result, clinical equipoise in corticosteroid therapy exists depending on geographical regions and the clinician's preference. SUMMARY Better understanding around the pathogenesis of IgAN has prompted several clinical trials exploring the effects of immunosuppressive agents including corticosteroids. Earlier studies of corticosteroids were limited by suboptimal study designs, inadequate implementation of standard of care, and inconsistent adverse event data collection. Two well-designed, adequately powered, multi-centre randomized controlled trials, the STOP-IgAN and TESTING studies, have reported contrasting kidney outcomes that have further fuelled the clinical conundrum regarding the efficacy of corticosteroids. Both studies independently reported greater adverse events with corticosteroids. A novel targeted release formulation of budesonide, which has been hypothesized to reduce the adverse events associated with systemic corticosteroids, has shown promising results in the Phase 3 NefigaRD trial. Studies of treatments targeting B cells and the complement cascade are currently underway, and early data appear encouraging. This review provides an overview of the current literature around the understanding of the pathomechanisms and benefits and harm of corticosteroid use in IgAN. KEY MESSAGES Recent evidence suggests the use of corticosteroids in a selected cohort of people with IgAN at high risk of disease progression can improve kidney outcomes but comes with an associated risk of treatment-related adverse events, particularly with higher doses. Management decisions should therefore follow an informed patient-clinician discussion.
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Affiliation(s)
- Dana Kim
- Renal and Metabolic Division, The George Institute for Global Health, Newtown, New South Wales, Australia
- Concord Clinical School, University of Sydney, Concord, New South Wales, Australia
| | - Muh Geot Wong
- Concord Clinical School, University of Sydney, Concord, New South Wales, Australia
- Department of Renal Medicine, Concord Repatriation General Hospital, Concord, New South Wales, Australia
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Wang D, Wu C, Chen S, Li Y, Wang L, Zhang Y, Li G. Urinary complement profile in IgA nephropathy and its correlation with the clinical and pathological characteristics. Front Immunol 2023; 14:1117995. [PMID: 37020564 PMCID: PMC10068869 DOI: 10.3389/fimmu.2023.1117995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 03/03/2023] [Indexed: 03/22/2023] Open
Abstract
Background and objectivesThe activated complement profile in IgA nephropathy (IgAN) is still unclear. Our study investigated the profile of urinary complements in IgAN patients and its correlations with clinical and pathological characteristics.MethodsUrinary protein abundance was detected by liquid chromatography-tandem mass spectrometry (LC–MS/MS) in 50 IgAN, 50 membranous nephropathy (MN), and 68 healthy controls (HC). Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to identify differentially expressed proteins in IgAN patients. The differentially expressed complement proteins were screened in IgAN patients, and their correlations with laboratory or pathological parameters were analyzed. Thereafter, 7 complement components were validated by enzyme-linked immunosorbent assay (ELISA) in the urine samples of 45 IgAN patients.ResultsThere were 786 differentially expressed proteins between IgAN and HC. KEGG analysis showed that differentially expressed urinary proteins in IgAN were enriched with complement. Of these, 67% of urinary complement protein abundance was associated with the estimated glomerular filtration rate. The urinary complement-related protein collectin12 (colec12), complement H factor (CFH), complement H factor-related protein 2 (CFHR2), and complement B factor (CFB) were positively correlated with serum creatinine; colec12, CFHR2, CFB, and C8g were positively correlated with glomerulosclerosis; CFH, CFHR2, C8g, and C9 were positively correlated with tubular atrophy/interstitial fibrosis.ConclusionAbnormally increased components of complement pathways significantly correlate with reduced renal function, proteinuria, and renal histological damage in IgAN. It could provide a potential biomarker panel for monitoring IgAN and provide clues for therapeutic choice targeting complement system of IgAN patients.
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Affiliation(s)
- Dongqing Wang
- Renal Department and Nephrology Institute, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Changwei Wu
- Renal Department and Nephrology Institute, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Sipei Chen
- Renal Department and Nephrology Institute, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Yi Li
- Renal Department and Nephrology Institute, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Li Wang
- Renal Department and Nephrology Institute, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Yong Zhang
- Institutes for Systems Genetics, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Guisen Li, ; Yong Zhang,
| | - Guisen Li
- Renal Department and Nephrology Institute, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- *Correspondence: Guisen Li, ; Yong Zhang,
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Xie M, Zhu Y, Wang X, Ren J, Guo H, Huang B, Wang S, Wang P, Liu Y, Liu Y, Zhang J. Predictive prognostic value of glomerular C3 deposition in IgA nephropathy. J Nephrol 2023; 36:495-505. [PMID: 35781866 DOI: 10.1007/s40620-022-01363-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 05/23/2022] [Indexed: 10/17/2022]
Abstract
BACKGROUND IgAN is the most common primary glomerulonephritis worldwide. However, the pathogenesis of IgAN remains unknown. Currently, there is evidence that C3 deposition plays a role in disease development. This study aimed to investigate clinical, pathological features, and prognosis of adult IgAN patients with C3 deposition, as well as explore the role of complement activation in disease progression. METHODS A total of 821 patients with biopsy-proven IgAN were included in this study. Patients were divided into three different groups according to their C3 deposition intensity. Clinical and pathological characteristics were compared between groups. Logistic analysis was used to estimate the relationship between C3 deposition and the Oxford scoring system. Univariate and multivariate Cox proportional hazard regression models were used to analyze the effect of the presence of C3 deposits on the prognosis of patients with IgA nephropathy. Kaplan-Meier survival analysis was used to evaluate the cumulative incidence of renal progression between groups. RESULTS Patients with C3 deposition exhibited more severe clinical and pathological features and had a higher score according to the Oxford scoring system. With the increasing intensity of C3 deposition, patients present more hematuria, crescents, heavier interstitial inflammatory cell infiltration and a higher score on segmental sclerosis lesions. Logistic regression identified a positive relationship between C3 deposition and histopathology. Univariate and multivariate Cox regression indicated that C3 deposition was an independent risk factor for IgAN severity. The Kaplan-Meier survival curves indicated that patients with positive C3 deposition had a worse prognosis compared to those without C3 deposition. CONCLUSIONS Patients with positive glomerular C3 deposition presented with more severe clinical and histopathological characteristics and a higher score on the Oxford scoring system. With the increasing intensity of C3 deposition, IgAN patients were more likely to present with high level of microscopic hematuria, fibrous crescents, interstitial inflammatory cell infiltration, and a higher score on segmental sclerosis lesions. C3 deposition at the time of renal biopsy is likely an independent risk factor for IgA nephropathy severity and progression.
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Affiliation(s)
- Minhua Xie
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- Research Institute of Nephrology, Zhengzhou University, Zhengzhou, Henan, China
| | - Yuze Zhu
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- Research Institute of Nephrology, Zhengzhou University, Zhengzhou, Henan, China
| | - Xutong Wang
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- Research Institute of Nephrology, Zhengzhou University, Zhengzhou, Henan, China
| | - Jingjing Ren
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- Research Institute of Nephrology, Zhengzhou University, Zhengzhou, Henan, China
| | - Haonan Guo
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- Research Institute of Nephrology, Zhengzhou University, Zhengzhou, Henan, China
| | - Bo Huang
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- Research Institute of Nephrology, Zhengzhou University, Zhengzhou, Henan, China
| | - Shulei Wang
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- Research Institute of Nephrology, Zhengzhou University, Zhengzhou, Henan, China
| | - Peiheng Wang
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- Research Institute of Nephrology, Zhengzhou University, Zhengzhou, Henan, China
| | - Yiming Liu
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- Research Institute of Nephrology, Zhengzhou University, Zhengzhou, Henan, China
| | - Yingchun Liu
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- Research Institute of Nephrology, Zhengzhou University, Zhengzhou, Henan, China
| | - Junjun Zhang
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
- Research Institute of Nephrology, Zhengzhou University, Zhengzhou, Henan, China.
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Guo WY, Sun LJ, Dong HR, Wang GQ, Xu XY, Cheng WR, Zhao ZR, Ye N, Liu Y, Cheng H. Characterization of patients with IgA nephropathy with and without associated minimal change disease. FRONTIERS IN NEPHROLOGY 2023; 3:1105933. [PMID: 37675352 PMCID: PMC10479556 DOI: 10.3389/fneph.2023.1105933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 01/25/2023] [Indexed: 09/08/2023]
Abstract
Introduction Immunoglobulin A nephropathy (IgAN) presents various clinical manifestations and pathological phenotypes. Approximately 5% of patients with IgAN present with early onset nephrotic syndrome, mild mesangial lesions, and diffuse foot process effacement of podocytes, which resemble minimal change disease (MCD). These patients are defined as MCD-IgAN. Whether MCD-IgAN is a special type of IgAN or simply MCD accompanied by IgA deposition remains controversial. Methods A total of 51 patients diagnosed with MCD-IgAN at Beijing Anzhen Hospital from January 2010 to September 2022 were recruited. The clinical and pathological characteristics of IgA-MCD were analyzed. Patients with IgAN but without MCD (non-MCD-IgAN) and healthy participants were enrolled as controls. Galactose-deficient immunoglobulin A1 (Gd-IgA1) and complement C3 were detected both in the circulation and in renal tissues. Results We found that the levels of serum Gd-IgA1 were lower in participants with MCD-IgAN than in those with non-MCD-IgAN, but higher than in healthy participants. Gd-IgA1 was rarely deposited in the glomeruli of participants with MCD-IgAN, with a positive rate of only 13.7% (7/51); in contrast, the positive rate in participants with non-MCD-IgAN was 82.4% (42/51). Among renal Gd-IgA1-positive patients, Gd-IgA1 and immunoglobulin A (IgA) colocalized along the glomerular mesangial and capillary areas. Interestingly, we found that the circulating levels of complement C3 were significantly higher in participants with MCD-IgAN than in participants with non-MCD-IgAN. In addition, the intensity of C3c in glomeruli in participants with MCD-IgAN was significantly weaker than in participants with non-MCD-IgAN. Conclusions Our study suggests that, in MCD-IgAN, most of the IgA that is deposited on glomeruli is not the same pathogenic Gd-IgA1 as found in general IgAN. Complement activation both in the circulation and in the renal locality was much weaker in MCD-IgAN than in non-MCD-IgAN. Our study suggests that IgAN with MCD might be MCD with coincidental IgA deposition.
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Affiliation(s)
- Wei-yi Guo
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Li-jun Sun
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Hong-rui Dong
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Guo-qin Wang
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Xiao-yi Xu
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Wen-rong Cheng
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Zhi-rui Zhao
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Nan Ye
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Yun Liu
- Division of Nephrology, Affiliated Hospital of Chifeng University, Chifeng, Inner Mongolia, China
| | - Hong Cheng
- Renal Division, Department of Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
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Nihei Y, Suzuki H, Suzuki Y. Current understanding of IgA antibodies in the pathogenesis of IgA nephropathy. Front Immunol 2023; 14:1165394. [PMID: 37114051 PMCID: PMC10126238 DOI: 10.3389/fimmu.2023.1165394] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 03/27/2023] [Indexed: 04/29/2023] Open
Abstract
Immunoglobulin A (IgA) is the most abundant isotype of antibodies, provides a first line of defense at mucosal surfaces against pathogens, and thereby contributes to mucosal homeostasis. IgA is generally considered as a non-inflammatory antibody because of its main function, neutralizing pathogenic virus or bacteria. Meanwhile, IgA can induce IgA-mediated diseases, such as IgA nephropathy (IgAN) and IgA vasculitis. IgAN is characterized by the deposition of IgA and complement C3, often with IgG and/or IgM, in the glomerular mesangial region, followed by mesangial cell proliferation and excessive synthesis of extracellular matrix in glomeruli. Almost half a century has passed since the first report of patients with IgAN; it remains debatable about the mechanism how IgA antibodies selectively bind to mesangial region-a hallmark of IgAN-and cause glomerular injuries in IgAN. Previous lectin- and mass-spectrometry-based analysis have revealed that IgAN patients showed elevated serum level of undergalactosylated IgA1 in O-linked glycans of its hinge region, called galactose-deficient IgA1 (Gd-IgA1). Thereafter, numerous studies have confirmed that the glomerular IgA from IgAN patients are enriched with Gd-IgA1; thus, the first hit of the current pathogenesis of IgAN has been considered to increase circulating levels of Gd-IgA1. Recent studies, however, demonstrated that this aberrant glycosylation alone is not sufficient to disease onset and progression, suggesting that several additional factors are required for the selective deposition of IgA in the mesangial region and induce nephritis. Herein, we discuss the current understanding of the characteristics of pathogenic IgA and its mechanism of inducing inflammation in IgAN.
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Affiliation(s)
- Yoshihito Nihei
- Department of Nephrology, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Hitoshi Suzuki
- Department of Nephrology, Juntendo University Faculty of Medicine, Tokyo, Japan
- Department of Nephrology, Juntendo University Urayasu Hospital, Chiba, Japan
- *Correspondence: Yusuke Suzuki, ; Hitoshi Suzuki,
| | - Yusuke Suzuki
- Department of Nephrology, Juntendo University Faculty of Medicine, Tokyo, Japan
- *Correspondence: Yusuke Suzuki, ; Hitoshi Suzuki,
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Habas E, Ali E, Farfar K, Errayes M, Alfitori J, Habas E, Ghazouani H, Akbar R, Khan F, Al Dab A, Elzouki AN. IgA nephropathy pathogenesis and therapy: Review & updates. Medicine (Baltimore) 2022; 101:e31219. [PMID: 36482575 PMCID: PMC9726424 DOI: 10.1097/md.0000000000031219] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND IgA nephropathy (IgAN) is the most frequent type of primary glomerulonephritis since the first type was described more than four decades ago. It is the prevalent cause of primary glomerular disease that causes end-stage renal disease. In most patients with IgAN, hematuria is the most common reported symptom, particularly in those with a preceding upper respiratory tract infection. Although the pathogenesis of IgAN is usually multifactorial, autoimmune complex formation and inflammatory processes are the most widely recognized pathogenic mechanisms. Multiple approaches have been trialed as a therapy for IgAN, including tonsillectomy, steroids, other immune-suppressive therapy in different regimens, and kidney transplantation. AIM AND METHOD PubMed, Google, Google Scholar, Scopus, and EMBASE were searched by the authors using different texts, keywords, and phrases. A non-systemic clinical review is intended to review the available data and clinical updates about the possible mechanism(s) of IgAN pathogenesis and treatments. CONCLUSION IgAN has a heterogeneous pattern worldwide, making it difficult to understand its pathogenesis and treatment. Proteinuria is the best guide to follow up on the IgAN progression and treatment response. Steroids are the cornerstone of IgAN therapy; however, other immune-suppressive and immune-modulative agents are used with a variable response rate. Kidney transplantation is highly advisable for IgAN patients, although the recurrence rate is high. Finally, IgAN management requires collaborative work between patients and their treating physicians for safe long-term outcomes.
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Affiliation(s)
- Elmukhtar Habas
- Hamad General Medicine, Doha, Qatar
- *Correspondence: Elmukhtar Habas, Internal Medicine, Hamad Medical Corporation, AL-Rayyan Road, PO Box 3050, Doha, Qatar (e-mail: )
| | - Elrazi Ali
- Hamad General Hospital, Medicine Department, Doha, Qatar
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Matsumoto Y, Aryal RP, Heimburg-Molinaro J, Park SS, Wever WJ, Lehoux S, Stavenhagen K, van Wijk JAE, Van Die I, Chapman AB, Chaikof EL, Cummings RD. Identification and characterization of circulating immune complexes in IgA nephropathy. SCIENCE ADVANCES 2022; 8:eabm8783. [PMID: 36306365 PMCID: PMC9616497 DOI: 10.1126/sciadv.abm8783] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 09/12/2022] [Indexed: 05/14/2023]
Abstract
The underlying pathology of immunoglobulin A (IgA) nephropathy (IgAN), the most common glomerulonephritis worldwide, is driven by the deposition of immune complexes containing galactose-deficient IgA1 [Tn(+)IgA1] in the glomerular mesangium. Here, we report that novel anti-Tn circulating immune complexes (anti-Tn CICs) contain predominantly IgM, representing large macromolecular complexes of ~1.2 megadaltons to several megadalton sizes together with Tn(+)IgA1 and some IgG. These complexes are significantly elevated in sera of patients with IgAN, which contains higher levels of complement C3, compared to healthy individuals. Anti-Tn CICs are bioactive and induce specific proliferation of human renal mesangial cells. We found that these anti-Tn CICs can be dissociated with small glycomimetic compounds, which mimic the Tn antigen of Tn(+)IgA1, releasing IgA1 from anti-Tn CICs. This glycomimetic compound can also significantly inhibit the proliferative activity of anti-Tn CICs of patients with IgAN. These findings could enhance both the diagnosis of IgAN and its treatment, as specific drug treatments are now unavailable.
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Affiliation(s)
- Yasuyuki Matsumoto
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Rajindra P. Aryal
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jamie Heimburg-Molinaro
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Simon S. Park
- Department of Surgery, Center for Drug Discovery and Translational Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Wyss Institute of Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Walter J. Wever
- Department of Surgery, Center for Drug Discovery and Translational Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Wyss Institute of Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Sylvain Lehoux
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Kathrin Stavenhagen
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Joanna A. E. van Wijk
- Department of Pediatric Nephrology, Amsterdam University Medical Centre, location VUmc, Amsterdam, Netherlands
| | - Irma Van Die
- Department of Molecular Cell Biology and Immunology, Amsterdam University Medical Centre, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Arlene B. Chapman
- Department of Medicine, Section of Nephrology, University of Chicago School of Medicine, Chicago, IL, USA
| | - Elliot L. Chaikof
- Department of Surgery, Center for Drug Discovery and Translational Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Wyss Institute of Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Richard D. Cummings
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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