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Yang D, Zhou H, Qin W. High systemic inflammatory response index (SIRI) is an independent risk factor for poor outcome in IgA nephropathy patients. Int Urol Nephrol 2024:10.1007/s11255-024-04171-w. [PMID: 39060722 DOI: 10.1007/s11255-024-04171-w] [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: 11/30/2023] [Accepted: 06/27/2024] [Indexed: 07/28/2024]
Abstract
BACKGROUND The systemic inflammatory response index (SIRI), a straightforward and easily accessible measure of inflammation and prognosis, has drawn more attention lately. It is unknown, however, if SIRI is important for IgA nephropathy (IgAN) patients' outcomes. To better clarify these concerns, we conducted this investigation. METHOD This retrospective study involved 981 patients with biopsy-confirmed IgAN from West China Hospital of Sichuan University between 2008 and 2019. The patients were divided into two groups based on the SIRI's optimal cut-off value calculated by the X-tile: the low SIRI group (SIRI ≤ 0.63, n = 312) and the high SIRI group (SIRI > 0.63, n = 669). Basic clinical characteristics at the time of renal biopsy were evaluated, and the relationship between SIRI and the combined endpoint was analyzed. We also used the Cox proportional hazard model and Kaplan‒Meier curve to evaluate the renal prognosis of IgAN. RESULTS A total of 981 IgAN patients were included. During a median follow-up period of 56.7 months (36.8-80.4 months), 122 patients progressed to the combined endpoint (12.4%). Patients were divided into a low SIRI group (SIRI ≤ 0.63, n = 312) and a high SIRI group (SIRI > 0.63, n = 669) according to the optimal cut-off value of the systemic inflammatory response index (SIRI). Further analysis showed that a higher SIRI value was significantly associated with the risk of IgAN patients reaching the composite endpoint (HR 1.62, 95% CI 1.02-2.56, p = 0.041). CONCLUSION High SIRI is a significant and independent risk factor for renal disease progression in IgAN patients.
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Affiliation(s)
- Dandan Yang
- Department of Nephrology, West China Hospital of Sichuan University, Chengdu, 610041, China
- West China School of Medicine, Sichuan University, Guoxue Alley 37, Chengdu, 610041, Sichuan, China
| | - Huan Zhou
- Department of Nephrology, West China Hospital of Sichuan University, Chengdu, 610041, China
- West China School of Medicine, Sichuan University, Guoxue Alley 37, Chengdu, 610041, Sichuan, China
| | - Wei Qin
- Department of Nephrology, West China Hospital of Sichuan University, Chengdu, 610041, China.
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2
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Zhang Y, Zhang H. Current understanding and new insights in the treatment of IgA nephropathy. Nephrology (Carlton) 2024. [PMID: 38958055 DOI: 10.1111/nep.14340] [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: 12/16/2023] [Accepted: 06/24/2024] [Indexed: 07/04/2024]
Abstract
IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide, and almost all patients are at risk of progression to end-stage kidney disease within their lifetime. The mechanisms responsible for the presentation and development of IgAN are required for the development of highly targeted therapies for this disease. In this review, we first demonstrate the current treatment strategy of IgAN recommended by the 2021 KDIGO guideline. Then, we update the new insights into disease pathogenesis based on the well acknowledged 'multiple-hit hypothesis' and provide the potential therapeutic targets involved in the upstream production of pathogenic IgA1 and the downstream complement activation. Finally, the recent large randomized controlled trials focusing on these novel targets have been summarized, among which Nefecon and Sparsentan have received approval and Telitacicept have been used off-label for IgAN. In the future, emerging treatment approaches for IgAN is likely to evolve, which will signify a shift in the management of the IgAN from traditional immunosuppressive approaches to an era of targeted treatment based on the understanding of the pathogenic mechanisms.
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Affiliation(s)
- Yuemiao Zhang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, China
- Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Hong Zhang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, China
- Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
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3
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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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4
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Zhao C, Zhang M, Zhao L, Sun W. From genomic insights to clinical hope: Targeting NEU1 in IgA nephropathy. Int Immunopharmacol 2024; 132:112051. [PMID: 38599098 DOI: 10.1016/j.intimp.2024.112051] [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: 01/31/2024] [Revised: 03/27/2024] [Accepted: 04/06/2024] [Indexed: 04/12/2024]
Abstract
BACKGROUND IgA Nephropathy (IgAN), the primary form of glomerulonephritis, presents significant clinical challenges due to its obscure pathogenesis and lack of targeted treatments. We conducted a proteome-wide Mendelian randomization (MR) study to identify therapeutic targets for IgAN. METHODS Utilizing a plasma proteome dataset comprising 4907 blood plasma proteins as the exposure variable, and renal biopsy-confirmed IgAN cases as the outcome, this study employed MR to pinpoint proteins potentially pathogenic to IgAN. The robustness of our findings was affirmed through external dataset validation, reverse causation testing, and Bayesian colocalization analysis. Additionally, we conducted phenotypic scanning and analyzed downstream metabolites to investigate candidate proteins's biological function. RESULTS In our study, a significant association was identified between an increase in neuraminidase 1 (NEU1) expression and the risk of IgAN. Specifically, a one standard deviation increase in NEU1 expression was associated with an odds ratio of 11.80 for the development of IgAN (95% confidence interval: 4.03-34.54). This association was substantiated across various statistical models and external validations. Colocalization analysis indicated a shared causal variant between NEU1 expression and IgAN. Furthermore, an increased influenza risk associated with NEU1 was observed, supporting the therapeutic potential of NEU1 inhibitors for IgAN. However, our study found no significant role for neuraminic acid-related metabolites in IgAN's development, suggesting an independent pathway for NEU1's influence. CONCLUSION This study identifies NEU1 as a promising therapeutic target for IgAN, backed by robust genetic evidence. Future research should explore NEU1's therapeutic potential in diverse populations and clinical scenarios, further establishing its role in IgAN.
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Affiliation(s)
- Cong Zhao
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100700, China.
| | - Mingzhu Zhang
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100700, China.
| | - Leying Zhao
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100700, China.
| | - Weiwei Sun
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100700, China.
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5
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Guzzo G, Sadallah S, Rousson V, Herrera-Gómez F, Pantaleo G, Pascual M, Teta D. Pilot Study of sC5b-9 and Bb Fragment Plasma Levels in Crescentic Immunoglobulin A Nephropathy. Kidney Int Rep 2024; 9:1517-1520. [PMID: 38707793 PMCID: PMC11068954 DOI: 10.1016/j.ekir.2024.02.1400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 01/27/2024] [Accepted: 02/13/2024] [Indexed: 05/07/2024] Open
Affiliation(s)
- Gabriella Guzzo
- Service of Nephrology, Valais Hospital, Sion, Switzerland
- Organ Transplant Center, Lausanne University Hospital, University of Lausanne, Lausanne, Switzerland
| | - Salima Sadallah
- Service of Immunology and Allergy, Lausanne University Hospital, University of Lausanne, Lausanne, Switzerland
| | - Valentin Rousson
- Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland
| | - Francisco Herrera-Gómez
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
- Organ Transplant Center, Lausanne University Hospital, University of Lausanne, Lausanne, Switzerland
| | - Giuseppe Pantaleo
- Service of Immunology and Allergy, Lausanne University Hospital, University of Lausanne, Lausanne, Switzerland
| | - Manuel Pascual
- Organ Transplant Center, Lausanne University Hospital, University of Lausanne, Lausanne, Switzerland
| | - Daniel Teta
- Service of Nephrology, Valais Hospital, Sion, Switzerland
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6
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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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7
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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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8
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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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9
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Vaz de Castro PAS, Amaral AA, Almeida MG, Selvaskandan H, Barratt J, Simões E Silva AC. Examining the association between serum galactose-deficient IgA1 and primary IgA nephropathy: a systematic review and meta-analysis. J Nephrol 2024:10.1007/s40620-023-01874-8. [PMID: 38427309 DOI: 10.1007/s40620-023-01874-8] [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: 09/19/2023] [Accepted: 12/26/2023] [Indexed: 03/02/2024]
Abstract
BACKGROUND IgA nephropathy (IgAN) is a common primary glomerular disease. The O-glycosylation status of IgA1 plays a crucial role in disease pathophysiology. The level of poorly-O-galactosylated IgA1, or galactose-deficient IgA1 (Gd-IgA1), has also been identified as a potential biomarker in IgAN. We sought to examine the value of serum Gd-IgA1 as a biomarker in IgAN, by investigating its association with clinical, laboratory, and histopathological features of IgAN. METHODS The review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations and was registered in PROSPERO (CRD42021287423). The literature search was conducted in PubMed, Web of Science, Cochrane, and Scopus, and the selected articles were evaluated for eligibility based on predefined criteria. The methodological quality of the studies was assessed using the Newcastle-Ottawa Scale. Statistical analysis was performed to calculate effect sizes and assess heterogeneity among the studies. RESULTS This review analyzed 29 out of 1,986 studies, conducted between 2005 and 2022, with participants from multiple countries. Gd-IgA1 levels were not associated with age and gender, while associations with hypertension, hematuria, and proteinuria were inconsistent. In the meta-analyses, a correlation between serum Gd-IgA1 and estimated glomerular filtration rate was identified, however, the relationships between Gd-IgA1 levels and chronic kidney disease (CKD) stage and progression to kidney failure were inconsistent. CONCLUSIONS Serum Gd-IgA1 levels were not associated with validated prognostic risk factors, but were negatively correlated with kidney function. Further research in larger studies using standardized assays are needed to establish the value of Gd-IgA1 as a prognostic risk factor in IgAN.
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Affiliation(s)
- Pedro Alves Soares Vaz de Castro
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Arthur Aguiar Amaral
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Mariana Godinho Almeida
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Haresh Selvaskandan
- The Mayer IgA Nephropathy Laboratories, University of Leicester, Leicester, UK
| | - Jonathan Barratt
- The Mayer IgA Nephropathy Laboratories, University of Leicester, Leicester, UK.
- Department of Cardiovascular Sciences, University of Leicester, University Road, Leicester, LE1 7RH, UK.
| | - Ana Cristina Simões E Silva
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
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Iwafuchi Y, Morioka T, Oyama Y, Narita I. A case of non-lupus full-house nephropathy diagnosed by kidney biopsy but observed IgA nephropathy on second biopsy. CEN Case Rep 2024:10.1007/s13730-024-00860-8. [PMID: 38421587 DOI: 10.1007/s13730-024-00860-8] [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: 10/17/2023] [Accepted: 02/12/2024] [Indexed: 03/02/2024] Open
Abstract
We describe a case of full-house nephropathy without any underlying disease, including systemic lupus erythematosus. A 40-year-old woman was referred to our hospital with mild proteinuria and microscopic hematuria. The patient was diagnosed with immune complex-mediated glomerulonephritis with a predominant mesangioproliferative pattern based on renal histopathological results using full-house immunofluorescence staining. She showed no clinical criteria for the diagnosis of systemic lupus erythematosus, except for kidney disorders, and tested negative for antinuclear antibodies throughout her clinical course. However, in the second kidney biopsy, no C1q or C4 were detected in the immunofluorescence study, suggesting an immunoglobulin A nephropathy-like pattern. The patient responded favorably to corticosteroid treatment. We found a heterozygous CFHR3-CFHR1 deletion. The association between full-house nephropathy and CFHR3-CFHR1 deletion is unknown, but its influence on the histological pattern in our case is suspected. This indicates the diversity in the pathogenesis of non-lupus full-house nephropathy and warrants further investigation.
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Affiliation(s)
- Yoichi Iwafuchi
- Department of Internal Medicine, Koseiren Sanjo General Hospital, 5-1-62 Tsukanome, Sanjo, 955-0055, Japan.
| | - Tetsuo Morioka
- Department of Internal Medicine, Shinrakuen Hospital, Kidney Center3-3-11 Shindoriminami Nishi-Ku, Niigata, 950-2087, Japan
| | - Yuko Oyama
- Department of Internal Medicine, Koseiren Sanjo General Hospital, 5-1-62 Tsukanome, Sanjo, 955-0055, Japan
| | - Ichiei Narita
- Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-Dori, Chuo-Ku, Niigata, 951-8510, Japan
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11
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Di Leo V, Annese F, Papadia F, Russo MS, Giliberti M, Sallustio F, Gesualdo L. Refractory IgA Nephropathy: A Challenge for Future Nephrologists. MEDICINA (KAUNAS, LITHUANIA) 2024; 60:274. [PMID: 38399561 PMCID: PMC10890070 DOI: 10.3390/medicina60020274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/25/2024]
Abstract
IgA nephropathy (IgAN) represents the most prevalent form of primary glomerulonephritis, and, on a global scale, it ranks among the leading culprits behind end-stage kidney disease (ESKD). Presently, the primary strategy for managing IgAN revolves around optimizing blood pressure and mitigating proteinuria. This is achieved through the utilization of renin-angiotensin system (RAS) inhibitors, namely, angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs). As outlined by the KDIGO guidelines, individuals who continue to show a persistent high risk of progressive ESKD, even with comprehensive supportive care, are candidates for glucocorticoid therapy. Despite these therapies, some patients have a disease refractory to treatment, defined as individuals that present a 24 h urinary protein persistently >1 g after at least two rounds of regular steroids (methylprednisolone or prednisone) and/or immunosuppressant therapy (e.g., mycophenolate mofetil), or who do not tolerate regular steroids and/or immunosuppressant therapy. The aim of this Systematic Review is to revise the current literature, using the biomedical database PubMed, to investigate possible therapeutic strategies, including SGLT2 inhibitors, endothelin receptor blockers, targeted-release budesonide, B cell proliferation and differentiation inhibitors, fecal microbiota transplantation, as well as blockade of complement components.
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12
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Caster DJ, Lafayette RA. The Treatment of Primary IgA Nephropathy: Change, Change, Change. Am J Kidney Dis 2024; 83:229-240. [PMID: 37742867 DOI: 10.1053/j.ajkd.2023.08.007] [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: 02/01/2023] [Revised: 07/20/2023] [Accepted: 08/07/2023] [Indexed: 09/26/2023]
Abstract
IgA nephropathy (IgAN) is the most common glomerular disease in the world. However, the approach to treatment remains controversial. There has been an explosion of clinical trials over the past decade both to further examine corticosteroid use and usher in additional treatment considerations, including 2 newly approved therapies for IgAN. Sodium glucose cotransporter 2 inhibitors are proving to be effective therapy across proteinuric chronic kidney diseases, and IgAN is not likely to be an exception. Further supportive agents are looking highly promising and so are novel agents that specifically focus on the pathophysiology of this disease, including endothelin blockade, complement inhibition, and B-cell targeted strategies. We suggest a present-day approach to treatment of individuals with IgAN, expose the limitations in our knowledge, and discuss new treatments that may arise, hoping they come with evidence about optimal utilization. Change appears to be inevitable for our approach to the treatment of IgA nephropathy. This is truly an exciting and optimistic time.
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Affiliation(s)
- Dawn J Caster
- Division of Nephrology and Hypertension, University of Louisville, Louisville, Kentucky
| | - Richard A Lafayette
- Division of Nephrology, Stanford University Medical Center, Stanford, California.
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Shrivastava S, Agnememel AB, Ndungo E, Islam D, Liang Y, Frenck RW, Pasetti MF. Oral immunization with Shigella sonnei WRSs2 and WRSs3 vaccine strains elicits systemic and mucosal antibodies with functional anti-microbial activity. mSphere 2024; 9:e0041923. [PMID: 38132716 PMCID: PMC10826362 DOI: 10.1128/msphere.00419-23] [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: 07/26/2023] [Accepted: 11/29/2023] [Indexed: 12/23/2023] Open
Abstract
Shigella causes bacillary dysentery and is responsible for a high burden of disease globally. Several studies have emphasized the value of functional antibody activity to understand Shigella immunity and correlates of protection. The anti-microbial function of local (mucosal) antibodies and their contribution to preventing Shigella infection remain unknown. The goal of this study was to identify the functional humoral immune effectors elicited by two Shigella sonnei live oral vaccine candidates, WRSs2 and WRSs3. Complement-dependent bactericidal [serum bactericidal antibody (SBA)/bactericidal antibody (BA)] and opsonophagocytic killing antibody (OPKA) activity were determined in sera and stool extracts as indicators of systemic and local anti-microbial immunity. High levels of SBA/BA and OPKA were detected in serum as well as in fecal extracts from volunteers who received a single dose of WRSs2 and WRSs3. Functional antibody activity peaked on days 10 and 14 post-vaccination in fecal and serum samples, respectively. Bactericidal and OPKA titers were closely associated. Peak fold rises in functional antibody titers in serum and fecal extracts were also associated. Antibody activity interrogated in IgG and IgA purified from stool fractions identified IgG as the primary driver of mucosal bactericidal and OPKA activity, with minimal functional activity of IgA alone, highlighting an underappreciated role for IgG in bacterial clearance in the mucosa. The combination of IgG and IgA in equal proportions enhanced bactericidal and OPKA titers hinting at a co-operative or synergistic action. Our findings provide insight into the functional anti-microbial capacity of vaccine-induced mucosal IgG and IgA and propose an operative local humoral effector of protective immunity.IMPORTANCEThere is an urgent need for a safe, effective, and affordable vaccine against Shigella. Understanding the immunological underpinning of Shigella infection and the make-up of protective immunity is critical to achieve the best approach to prevent illness caused by this mucosal pathogen. We measured the complement-dependent bactericidal and opsonophagocytic antibody killing in serum and stool extracts from adult volunteers vaccinated with Shigella sonnei live oral vaccine candidates WRSs2 and WRSs3. For the first time, we detected functional antibody responses in stool samples that were correlated with those in sera. Using purified stool IgA and IgG fractions, we found that functional activity was mediated by IgG, with some help from IgA. These findings provide insight into the functional anti-microbial capacity of vaccine-induced mucosal IgG and IgA and support future studies to identify potential markers of protective mucosal immunity.
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Affiliation(s)
- Shikha Shrivastava
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Alain B. Agnememel
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Esther Ndungo
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Dilara Islam
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Yuanyuan Liang
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Robert W. Frenck
- Division of Infectious Diseases, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
| | - Marcela F. Pasetti
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
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14
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Monach PA. Complement. Arthritis Rheumatol 2024; 76:1-8. [PMID: 37551641 DOI: 10.1002/art.42671] [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: 06/22/2023] [Revised: 07/24/2023] [Accepted: 07/25/2023] [Indexed: 08/09/2023]
Abstract
The role of complement in human autoimmune, inflammatory, and infectious diseases is reviewed, focusing on clinical applicability. A typical case is presented in which serum testing for C3 and C4 is performed to help assess a syndrome with a broad differential diagnosis. The review includes a discussion of complement deficiency states, consumption of complement by diseases characterized by immune-complex formation and deposition, usefulness and interpretation of laboratory tests for complement, and development of drugs targeting specific components of the complement pathway for a growing number of indications.
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Affiliation(s)
- Paul A Monach
- VA Boston Healthcare System and Harvard Medical School, Boston, Massachusetts
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15
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Marro J, Chetwynd AJ, Hawkes J, Northey SJ, Oni L. Urinary markers of the alternative and lectin complement pathway are increased in IgA vasculitis nephritis. Clin Kidney J 2023; 16:2703-2711. [PMID: 38046006 PMCID: PMC10689168 DOI: 10.1093/ckj/sfad236] [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: 05/09/2023] [Indexed: 12/05/2023] Open
Abstract
Background IgA vasculitis (IgAV) is the most common form of childhood vasculitis. Nephritis (IgAVN) occurs in 50% of patients and 1-2% progress to chronic kidney disease stage 5. The pathophysiology of nephritis remains largely unknown, but recent evidence suggests that the complement system may be involved. The aim of this cross-sectional study was to explore whether there is evidence of alternative and/or lectin complement pathway activation in children with IgAVN. Methods Children with IgAV were recruited and grouped according to proteinuria: IgAVN or IgAV without nephritis (IgAVwoN). Age and sex-matched healthy controls (HCs) were also recruited. Cross-sectional urine and plasma concentrations of complement factor D (CFD), factor B (CFB), and MBL-associated protease 1 (MASP-1) were performed using commercially available enzyme-linked immunoassays. Results A total of 50 children were included (IgAVN, n = 15; IgAVwoN, n = 20, HCs, n = 15). The mean age was 8.5 ± 3.7 years old, male:female ratio was 1:1. Urinary CFD and CFB concentrations were statistically significantly increased in children with IgAVN (3.5 ± 5.4 μg/mmol; 25.9 ± 26.5 μg/mmol, respectively) compared to both IgAVwoN (0.4 ± 0.4 μg/mmol, P = 0.002; 9.2 ± 11.5 μg/mmol, P = 0.004) and HCs (0.3 ± 0.2 μg/mmol, P < 0.001; 5.1 ± 6.0 μg/mmol, P < 0.001). No statistically significant difference was reported for the plasma concentrations of CFD and CFB. Urinary MASP-1 concentrations were statistically significantly increased in IgAVN (116.9 ± 116.7 ng/mmol) compared to HCs (41.4 ± 56.1 ng/mmol, P = 0.006) and plasma MASP-1 concentrations were increased in IgAVwoN (254.2 ± 23.3 ng/mL) compared to HCs (233.4 ± 6.6 ng/mL, P = 0.046). Conclusion There is evidence of complement pathway products in the urine of children with IgAVN that warrants further investigation.
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Affiliation(s)
- Julien Marro
- Department of Women's and Children's Health, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Andrew J Chetwynd
- Department of Women's and Children's Health, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
- Centre for Proteome Research, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Jennifer Hawkes
- Department of Women's and Children's Health, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Sarah J Northey
- Department of Women's and Children's Health, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Louise Oni
- Department of Women's and Children's Health, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
- Department of Paediatric Nephrology, Alder Hey Children's NHS Foundation Trust Hospital, Liverpool, UK
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16
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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: 4] [Impact Index Per Article: 4.0] [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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17
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Cattran DC, Floege J, Coppo R. Evaluating Progression Risk in Patients With Immunoglobulin A Nephropathy. Kidney Int Rep 2023; 8:2515-2528. [PMID: 38106572 PMCID: PMC10719597 DOI: 10.1016/j.ekir.2023.09.020] [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: 06/06/2023] [Revised: 09/05/2023] [Accepted: 09/08/2023] [Indexed: 12/19/2023] Open
Abstract
The highly variable rate of decline in kidney function in patients with immunoglobulin A nephropathy (IgAN) provides a major clinical challenge. Predicting which patients will progress to kidney failure, and how quickly, is difficult. Multiple novel therapies are likely to be approved in the short-term, but clinicians lack the tools to identify patients most likely to benefit from specific treatments at the right time. Noninvasive and validated markers for selecting at-risk patients and longitudinal monitoring are urgently needed. This review summarizes what is known about demographic, clinical, and histopathologic prognostic markers in the clinician's toolkit, including the International IgAN Prediction Tool. We also briefly review what is known on these topics in children and adolescents with IgAN. Although helpful, currently used markers leave clinicians heavily reliant on histologic features from the diagnostic kidney biopsy and standard clinical data to guide treatment choice, and very few noninvasive markers reflect treatment efficacy over time. Novel prognostic and predictive markers are under clinical investigation, with considerable progress being made in markers of complement activation. Other areas of research are the interplay between gut microbiota and galactose-deficient IgA1 expression; microRNAs; imaging; artificial intelligence; and markers of fibrosis. Given the rate of therapeutic advancement, the remaining gaps in biomarker research need to be addressed. We finish by describing our route to clinical utility of predictive and prognostic markers in IgAN. This route will provide us with the chance to improve IgAN prognosis by using robust, clinically practical markers to inform patient care.
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Affiliation(s)
| | - Jürgen Floege
- Division of Nephrology and Clinical Immunology, RWTH Aachen University, Aachen, Germany
| | - Rosanna Coppo
- Fondazione Ricerca Molinette, Regina Margherita Hospital, Turin, Italy
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18
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Lasorsa F, Rutigliano M, Milella M, Ferro M, Pandolfo SD, Crocetto F, Simone S, Gesualdo L, Battaglia M, Ditonno P, Lucarelli G. Complement System and the Kidney: Its Role in Renal Diseases, Kidney Transplantation and Renal Cell Carcinoma. Int J Mol Sci 2023; 24:16515. [PMID: 38003705 PMCID: PMC10671650 DOI: 10.3390/ijms242216515] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 11/15/2023] [Accepted: 11/18/2023] [Indexed: 11/26/2023] Open
Abstract
The crosstalk among the complement system, immune cells, and mediators of inflammation provides an efficient mechanism to protect the organism against infections and support the repair of damaged tissues. Alterations in this complex machinery play a role in the pathogenesis of different diseases. Core complement proteins C3 and C5, their activation fragments, their receptors, and their regulators have been shown to be active intracellularly as the complosome. The kidney is particularly vulnerable to complement-induced damage, and emerging findings have revealed the role of complement system dysregulation in a wide range of kidney disorders, including glomerulopathies and ischemia-reperfusion injury during kidney transplantation. Different studies have shown that activation of the complement system is an important component of tumorigenesis and its elements have been proved to be present in the TME of various human malignancies. The role of the complement system in renal cell carcinoma (RCC) has been recently explored. Clear cell and papillary RCC upregulate most of the complement genes relative to normal kidney tissue. The aim of this narrative review is to provide novel insights into the role of complement in kidney disorders.
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Affiliation(s)
- Francesco Lasorsa
- Department of Precision and Regenerative Medicine and Ionian Area-Urology, Andrology and Kidney Transplantation Unit, University of Bari “Aldo Moro”, 70124 Bari, Italy
| | - Monica Rutigliano
- Department of Precision and Regenerative Medicine and Ionian Area-Urology, Andrology and Kidney Transplantation Unit, University of Bari “Aldo Moro”, 70124 Bari, Italy
| | - Martina Milella
- Department of Precision and Regenerative Medicine and Ionian Area-Urology, Andrology and Kidney Transplantation Unit, University of Bari “Aldo Moro”, 70124 Bari, Italy
| | - Matteo Ferro
- Division of Urology, European Institute of Oncology, IRCCS, 71013 Milan, Italy
| | - Savio Domenico Pandolfo
- Department of Neurosciences and Reproductive Sciences and Odontostomatology, University of Naples “Federico II”, 80131 Naples, Italy
| | - Felice Crocetto
- Department of Neurosciences and Reproductive Sciences and Odontostomatology, University of Naples “Federico II”, 80131 Naples, Italy
| | - Simona Simone
- Department of Precision and Regenerative Medicine and Ionian Area-Nephrology, Dialysis and Transplantation Unit, University of Bari “Aldo Moro”, 70124 Bari, Italy
| | - Loreto Gesualdo
- Department of Precision and Regenerative Medicine and Ionian Area-Nephrology, Dialysis and Transplantation Unit, University of Bari “Aldo Moro”, 70124 Bari, Italy
| | - Michele Battaglia
- Department of Precision and Regenerative Medicine and Ionian Area-Urology, Andrology and Kidney Transplantation Unit, University of Bari “Aldo Moro”, 70124 Bari, Italy
| | - Pasquale Ditonno
- Department of Precision and Regenerative Medicine and Ionian Area-Urology, Andrology and Kidney Transplantation Unit, University of Bari “Aldo Moro”, 70124 Bari, Italy
| | - Giuseppe Lucarelli
- Department of Precision and Regenerative Medicine and Ionian Area-Urology, Andrology and Kidney Transplantation Unit, University of Bari “Aldo Moro”, 70124 Bari, Italy
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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: 0] [Impact Index Per Article: 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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20
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Hutchinson S, Pereira N. Immunoglobulin A Nephropathy Presenting After Streptococcal Pharyngitis: A Case Report. Cureus 2023; 15:e46531. [PMID: 37927621 PMCID: PMC10625438 DOI: 10.7759/cureus.46531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2023] [Indexed: 11/07/2023] Open
Abstract
Immunoglobulin A (IgA) nephropathy (IgAN) is a condition characterized by IgA glomerular deposits with local cellular proliferation on renal biopsy. IgAN is the most common glomerular disease and the most common cause of renal failure worldwide. IgAN's pathogenesis is hypothesized as a four-hit process causing improper IgA production. Four-hit processes result in an increased level of circulating galactose deficient IgA1 (Gd-IgA1). In response, Gd-IgA1 is perceived as an autoantigen by other antibodies leading to renal tissue injury. This report outlines a case of a 15-year-old Hispanic male who presented to the Emergency Department with complaints of fever and hematuria, a week after testing positive for streptococcal pharyngitis. This case summarizes the presentation and management of IgAN.
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Affiliation(s)
- Stedrea Hutchinson
- College of Medicine, Saint James School of Medicine St. Vincent, Arnos Vale, VCT
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21
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Mei Z, Li F, Chen R, Xiao Z, Cai D, Jin L, Qian X, Wang Y, Chen J. Causal associations between thyroid cancer and IgA nephropathy: a Mendelian randomization study. BMC Genomics 2023; 24:525. [PMID: 37670254 PMCID: PMC10478414 DOI: 10.1186/s12864-023-09633-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 08/28/2023] [Indexed: 09/07/2023] Open
Abstract
BACKGROUND The incidence of kidney disease caused by thyroid cancer is rising worldwide. Observational studies cannot recognize whether thyroid cancer is independently associated with kidney disease. We performed the Mendelian randomization (MR) approach to genetically investigate the causality of thyroid cancer on immunoglobulin A nephropathy (IgAN). METHODS AND RESULTS We explored the causal effect of thyroid cancer on IgAN by MR analysis. Fifty-two genetic loci and single nucleotide polymorphisms were related to thyroid cancer. The primary approach in this MR analysis was the inverse variance weighted (IVW) method, and MR‒Egger was the secondary method. Weighted mode and penalized weighted median were used to analyze the sensitivity. In this study, the random-effect IVW models showed the causal impact of genetically predicted thyroid cancer across the IgAN risk (OR, 1.191; 95% CI, 1.131-1.253, P < 0.001). Similar results were also obtained in the weighted mode method (OR, 1.048; 95% CI, 0.980-1.120, P = 0.179) and penalized weighted median (OR, 1.185; 95% CI, 1.110-1.264, P < 0.001). However, the MR‒Egger method revealed that thyroid cancer decreased the risk of IgAN, but this difference was not significant (OR, 0.948; 95% CI, 0.855-1.051, P = 0.316). The leave-one-out sensitivity analysis did not reveal the driving influence of any individual SNP on the association between thyroid cancer and IgAN. CONCLUSION The IVW model indicated a significant causality of thyroid cancer with IgAN. However, MR‒Egger had a point estimation in the opposite direction. According to the MR principle, the evidence of this study did not support a stable significant causal association between thyroid cancer and IgAN. The results still need to be confirmed by future studies.
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Affiliation(s)
- Ziwei Mei
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310000, China
- Lishui Municipal Central hospital, Lishui, Zhejiang, 323000, China
| | - Fuhao Li
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310000, China
| | - Ruizhen Chen
- Department of Cardiology, Zhongshan Hospital, Shanghai Institute of Cardiovascular Diseases, Shanghai Medical College of Fudan University, Shanghai, China
| | - Zilong Xiao
- Department of Cardiology, Zhongshan Hospital, Shanghai Institute of Cardiovascular Diseases, Shanghai Medical College of Fudan University, Shanghai, China
| | - Dongsheng Cai
- Department of Cardiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Lie Jin
- Lishui Municipal Central hospital, Lishui, Zhejiang, 323000, China
| | - Xu Qian
- Department of Clinical Laboratory, The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, Hangzhou, 310022, China.
| | - Yucheng Wang
- Department of Cardiology, Zhongshan Hospital, Shanghai Institute of Cardiovascular Diseases, Shanghai Medical College of Fudan University, Shanghai, China.
| | - Jun Chen
- Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 310000, China.
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22
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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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23
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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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Guo Y, Zhang H, Yu X. A bibliometric analysis of complement in IgA nephropathy from 1991 to 2022. Front Pharmacol 2023; 14:1200193. [PMID: 37576817 PMCID: PMC10414182 DOI: 10.3389/fphar.2023.1200193] [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: 04/04/2023] [Accepted: 07/17/2023] [Indexed: 08/15/2023] Open
Abstract
Introduction: IgA nephropathy is a common glomerular disease on a global scale, which has resulted in significant economic burdens. The complement system plays a vital role in enhancing the efficacy of antibodies and phagocytic cells in eliminating microbes and damaged cells, and promoting inflammation. Complement activation has been found to contribute to the progression of various renal diseases, including IgA nephropathy. Methods: In this study, a thorough analysis was conducted on publications related to complement in IgAN from 1991 to 2022, retrieved from the Web of Science Core Collection and Scopus database. The analysis focused on various aspects such as annual publications, country, institution, author, journal, keywords, and co-cited references, utilizing Citespace and Vosviewer. Results: A total of 819 publications were obtained, and while there were slight fluctuations in annual publications, an overall upward trend was observed. China, Japan and the United States were the leading countries in terms of publications, with China having the highest number of publications (201). Collaborative network analysis revealed that England, University of Alabama Birmingham, and Robert J Wyatt were the most influential country, institution, and author, respectively, in this field of research. Furthermore, the analysis of references and keywords indicated that complement activation contributes to IgAN, and immunosuppression in IgAN are a hot topic of research. Discussion: This study identifies current research hotspots and advanced tendencies in the study of complement in IgAN, providing scholars with crucial directions in this research area.
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Affiliation(s)
- Yun Guo
- The First Clinical Medical College, Guangdong Medical University, Zhanjiang, China
- Department of Nephrology, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | | | - Xueqing Yu
- The First Clinical Medical College, Guangdong Medical University, Zhanjiang, China
- Department of Nephrology, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
- Guangdong-Hong Kong Joint Laboratory on Immunological and Genetic Kidney Diseases, Guangzhou, China
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Si FL, Tang C, Lv JC, Shi SF, Zhou XJ, Liu LJ, Zhang H. Comparison between hydroxychloroquine and systemic corticosteroids in IgA nephropathy: a two-year follow-up study. BMC Nephrol 2023; 24:175. [PMID: 37322444 PMCID: PMC10268518 DOI: 10.1186/s12882-023-03238-7] [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: 03/12/2023] [Accepted: 06/09/2023] [Indexed: 06/17/2023] Open
Abstract
BACKGROUND Hydroxychloroquine (HCQ) is recommended as a treatment for IgA nephropathy (IgAN) to control proteinuria. The long-term effects of HCQ compared to systemic corticosteroid therapy remain unclear. METHODS We conducted a retrospective case‒control study at Peking University First Hospital. Thirty-nine patients with IgAN who received HCQ for at least 24 months without corticosteroids (CSs) or other immunosuppressive agents were included. Thirty-nine matched patients who received systemic CS therapy were selected using propensity score matching. Clinical data over a 24-month period were compared. RESULTS In the HCQ group, the level of proteinuria decreased from 1.72 [1.44, 2.35] to 0.97 [0.51, 1.37] g/d (-50.5 [-74.0, -3.4] %, P < 0.001) at 24 months. A significant decline in proteinuria was also found in the CS group, but no significant differences were found between the HCQ group and CS group in the levels of proteinuria (0.97 [0.51, 1.37] vs. 0.53 [0.25, 1.81] g/d, P = 0.707) and change rates (-50.5% [-74.0%, -3.4%] vs. -63.7% [-78.5%, -24.2%], P = 0.385) at 24 months. In addition, the decline rates of eGFR between the HCQ and CS groups were comparable (-7.9% [-16.1%, 5.8%] vs. -6.6% [-14.9%, 5.3%], P = 0.758). More adverse events were observed in the CS group. CONCLUSIONS Long-term use of HCQ can maintain stable renal function with minimal side effects. In patients who cannot tolerate corticosteroids, HCQ might be an effective and safe supportive therapy for IgAN.
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Affiliation(s)
- Feng-Lei Si
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, China
- Key Laboratory of Renal Disease, Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Health of China, Ministry of Education, Beijing, China
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Chen Tang
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, China
- Key Laboratory of Renal Disease, Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Health of China, Ministry of Education, Beijing, China
- 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, Peking University Institute of Nephrology, Beijing, China
- Key Laboratory of Renal Disease, Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Health of China, Ministry of Education, Beijing, China
- 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, Peking University Institute of Nephrology, Beijing, China
- Key Laboratory of Renal Disease, Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Health of China, Ministry of Education, Beijing, China
- 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, Peking University Institute of Nephrology, Beijing, China
- Key Laboratory of Renal Disease, Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Health of China, Ministry of Education, Beijing, China
- 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, Peking University Institute of Nephrology, Beijing, China.
- Key Laboratory of Renal Disease, Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Health of China, Ministry of Education, Beijing, China.
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China.
- Renal Division, Key Laboratory of Renal Disease, Peking University First Hospital, Peking University Institute of Nephrology, Ministry of Health of China, Beijing, 100034, PR China.
| | - Hong Zhang
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, China
- Key Laboratory of Renal Disease, Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Health of China, Ministry of Education, Beijing, China
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
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Yu K, Ding L, An X, Yang Y, Zhang X, Li L, Wang C, Bai F, Yang X. APOC1 exacerbates renal fibrosis through the activation of the NF-κB signaling pathway in IgAN. Front Pharmacol 2023; 14:1181435. [PMID: 37305534 PMCID: PMC10248024 DOI: 10.3389/fphar.2023.1181435] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Introduction: IgA nephropathy (IgAN) is the most common disease leading to end-stage renal disease, and tubular fibrosis represents an important risk factor for disease progression. However, research on early molecular diagnostic indicators of tubular fibrosis and the mechanisms underlying disease progression is still lacking. Methods: The GSE93798 dataset was downloaded from the GEO database. DEGs were screened and analyzed for GO and KEGG enrichment in IgAN. The least absolute shrinkage and selection operator (LASSO) and support vector machine recursive feature elimination (SVM-RFE) algorithms were applied to screen for hub secretory genes. The expression and diagnostic efficacy of hub genes were confirmed by the GSE35487 dataset. ELISA was applied to detect the expression of APOC1 in serum. The expression and localization of hub genes in IgAN were verified by the expression of IHC and IF in human kidney tissues, and the correlation of expression with clinical data was verified in the Nephroseq database. Finally, cellular experiments clarified the role of hub genes in the signaling pathway. Results: A total of 339 DEGs were identified in IgAN, of which 237 were upregulated and 102 downregulated. The KEGG signaling pathway is enriched in the ECM-receptor interaction and AGE-RAGE signaling pathway. APOC1, ALB, CCL8, CXCL2, SRPX2, and TGFBI identified six hub secretory genes using the LASSO and SVM-RFE algorithms. In vivo and in vitro experiments demonstrated that APOC1 expression was elevated in IgAN. The serum concentration of APOC1 was 1.232 ± 0.1812 μg/ml in IgAN patients, whereas it was 0.3956 ± 0.1233 μg/ml in healthy individuals. APOC1 exhibited high diagnostic efficacy for IgAN (AUC of 99.091%, specificity of 95.455%, and sensitivity of 99.141%) in the GSE93798 dataset. APOC1 expression negatively correlated with eGFR (R 2 = 0.2285, p = 0.0385) and positively correlated with serum creatinine (R 2 = 0.41, p = 0.000567) in IgAN. APOC1 exacerbated renal fibrosis, possibly in part by activating the NF-κB pathway in IgAN. Conclusion: APOC1 was identified as the core secretory gene of IgAN, which was closely associated with blood creatinine and eGFR and had significant efficacy in the diagnosis of IgAN. Mechanistic studies revealed that the knockdown of APOC1 could improve IgAN renal fibrosis by inhibiting the NF pathway, which may be a potential therapeutic target for improving renal fibrosis in IgAN.
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Affiliation(s)
- Kuipeng Yu
- Department of Nephrology, Qilu Hospital of Shandong University, Jinan, Shandong, China
- Department of Blood Purification, Qilu Hospital of Shandong University, Jinan, Shandong, China
- Laboratory of Basic Medical Sciences, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Lin Ding
- Department of Nephrology, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Xin An
- Department of Nephrology, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Yanjiang Yang
- Department of Nephrology, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Xiaoning Zhang
- Department of Nephrology, Shengli Oilfield Central Hospital, Dongying, Shandong, China
| | - Luyao Li
- Department of Nephrology, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Chunjie Wang
- Department of Nephrology, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Fang Bai
- Department of Nephrology, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Xiangdong Yang
- Department of Nephrology, Qilu Hospital of Shandong University, Jinan, Shandong, China
- Department of Blood Purification, Qilu Hospital of Shandong University, Jinan, Shandong, 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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Rizk DV, Rovin BH, Zhang H, Kashihara N, Maes B, Trimarchi H, Perkovic V, Meier M, Kollins D, Papachristofi O, Charney A, Barratt J. Targeting the Alternative Complement Pathway With Iptacopan to Treat IgA Nephropathy: Design and Rationale of the APPLAUSE-IgAN Study. Kidney Int Rep 2023; 8:968-979. [PMID: 37180505 PMCID: PMC10166738 DOI: 10.1016/j.ekir.2023.01.041] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/06/2023] [Accepted: 01/30/2023] [Indexed: 02/11/2023] Open
Abstract
Introduction Targeting the alternative complement pathway (AP) is an attractive therapeutic strategy because of its role in immunoglobulin A nephropathy (IgAN) pathophysiology. Iptacopan (LNP023), a proximal complement inhibitor that specifically binds to factor B and inhibits the AP, reduced proteinuria and attenuated AP activation in a Phase 2 study of patients with IgAN, thereby supporting the rationale for its evaluation in a Phase 3 study. Methods APPLAUSE-IgAN (NCT04578834) is a multicenter, randomized, double-blind, placebo-controlled, parallel-group, Phase 3 study enrolling approximately 450 adult patients (aged ≥18 years) with biopsy-confirmed primary IgAN at high risk of progression to kidney failure despite optimal supportive treatment. Eligible patients receiving stable and maximally tolerated doses of angiotensin-converting enzyme inhibitors (ACEis) or angiotensin receptor blockers (ARBs) will be randomized 1:1 to either iptacopan 200 mg or placebo twice daily for a 24-month treatment period. A prespecified interim analysis (IA) will be performed when approximately 250 patients from the main study population complete the 9-month visit. The primary objective is to demonstrate superiority of iptacopan over placebo in reducing 24-hour urine protein-to-creatinine ratio (UPCR) at the IA and demonstrate the superiority of iptacopan over placebo in slowing the rate of estimated glomerular filtration rate (eGFR) decline (total eGFR slope) estimated over 24 months at study completion. The effect of iptacopan on patient-reported outcomes, safety, and tolerability will be evaluated as secondary outcomes. Conclusions APPLAUSE-IgAN will evaluate the benefits and safety of iptacopan, a novel targeted therapy for IgAN, in reducing complement-mediated kidney damage and thus slowing or preventing disease progression.
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Affiliation(s)
- Dana V. Rizk
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Brad H. Rovin
- Division of Nephrology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Hong Zhang
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, People’s Republic of China
| | - Naoki Kashihara
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Japan
| | - Bart Maes
- Department of Nephrology, AZ Delta, Roeselare, Belgium
| | - Hernán Trimarchi
- Nephrology Service and Kidney Transplantation Unit, Hospital Británico de Buenos Aires, Buenos Aires, Argentina
| | - Vlado Perkovic
- University of New South Wales, Sydney, New South Wales, Australia
| | | | | | | | - Alan Charney
- Novartis Pharmaceuticals Corporation, East Hanover, New Jersey, USA
| | - Jonathan Barratt
- Department of Cardiovascular Sciences, University of Leicester and The John Walls Renal Unit, University Hospitals of Leicester NHS Trust, Leicester, UK
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Zhou W, Wang H, Sun S, Shen Y, Liu X, Zhen J, Zhang H, Duan F, Pan Y, Dong L. Association between glomerular C4d deposition, proteinuria, and disease severity in children with IgA nephropathy. Pediatr Nephrol 2023; 38:1147-1157. [PMID: 36102962 DOI: 10.1007/s00467-022-05725-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND C4d may be used as a marker to evaluate the condition and prognosis of adults with IgA nephropathy, but there have been few studies of children with IgA nephropathy. METHODS C4d immunohistochemical staining was performed on samples from children with IgA nephropathy with C1q-negative immunofluorescence. The clinical and pathological treatment and prognostic characteristics of children in the C4d-positive and -negative groups were compared. RESULTS A total of sixty-five children with IgA nephropathy were included in the study and were followed up for an average of 37 months. C4d was mainly deposited along the capillary loops. The urinary protein-to-creatinine ratio (UPCR) in the C4d-positive group was significantly higher than that in the C4d-negative group (3.97 vs. 0.81, P < 0.001), and the average integrated optical density value of each child was positively correlated with the UPCR (r = 0.441, P < 0.001). There was a significant difference in the proportions of children with mesangial hypercellularity (M1) (68.97% vs. 44.44%, P = 0.048) and segmental glomerulosclerosis (S1) (65.52% vs. 33.33%, P = 0.010) between the C4d-positive group and the C4d-negative group. The proportion of children who received immunosuppressants in the C4d-positive group was higher than that in the C4d-negative group (86.21% vs. 36.11%, P < 0.001). There was no significant difference in the proportion of children developing kidney failure between the two groups. CONCLUSION C4d was found to be associated with proteinuria, segmental lesions, and immunosuppressant treatment. Activation of the lectin pathway may reflect the severity of clinical and pathological manifestations of IgA nephropathy in children. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Weiran Zhou
- Department of Pediatric Nephrology, Rheumatology and Immunology, Children's Hospital Affiliated to Shandong University, Jinan Children's Hospital, Jinan, Shandong Province, China
| | - Hui Wang
- Department 2 of Nephrology, Beijing Children's Hospital Affiliated to Capital Medical University, National Center for Children's Health, Key Laboratory of Major Diseases in Children's Ministry of Education, Beijing Key Laboratory of Pediatric Chronic Kidney Diseases and Blood Purification, Beijing, China.
| | - Shuzhen Sun
- Department of Pediatric Nephrology, Rheumatology and Immunology, Shandong Provincial Hospital, Shandong University, Jinan, China
| | - Ying Shen
- Department 2 of Nephrology, Beijing Children's Hospital Affiliated to Capital Medical University, National Center for Children's Health, Key Laboratory of Major Diseases in Children's Ministry of Education, Beijing Key Laboratory of Pediatric Chronic Kidney Diseases and Blood Purification, Beijing, China
| | - Xuemei Liu
- Department of Pediatric Nephrology, Rheumatology and Immunology, Children's Hospital Affiliated to Shandong University, Jinan Children's Hospital, Jinan, Shandong Province, China
| | - Junhui Zhen
- Department of Pathology, Shandong University, Jinan, China
| | - Hongxia Zhang
- Department of Pediatric Nephrology, Rheumatology and Immunology, Children's Hospital Affiliated to Shandong University, Jinan Children's Hospital, Jinan, Shandong Province, China
| | - Fan Duan
- Department 2 of Nephrology, Beijing Children's Hospital Affiliated to Capital Medical University, National Center for Children's Health, Key Laboratory of Major Diseases in Children's Ministry of Education, Beijing Key Laboratory of Pediatric Chronic Kidney Diseases and Blood Purification, Beijing, China
| | - Yanyan Pan
- Department of Pediatric Nephrology, Rheumatology and Immunology, Children's Hospital Affiliated to Shandong University, Jinan Children's Hospital, Jinan, Shandong Province, China
| | - Linlin Dong
- Department of Pediatric Nephrology, Rheumatology and Immunology, Children's Hospital Affiliated to Shandong University, Jinan Children's Hospital, Jinan, Shandong Province, China
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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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Guan J, Wang M, Zhao M, Ni W, Zhang M. Discovery of Fibrinogen γ-chain as a potential urinary biomarker for renal interstitial fibrosis in IgA nephropathy. BMC Nephrol 2023; 24:60. [PMID: 36941570 PMCID: PMC10029243 DOI: 10.1186/s12882-023-03103-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 03/03/2023] [Indexed: 03/23/2023] Open
Abstract
BACKGROUND IgA nephropathy (IgAN) is a major cause of chronic kidney disease (CKD). Renal interstitial fibrosis is a hallmark of CKD progression. Non-invasive biomarkers are needed to dynamically evaluate renal fibrosis. Data independent acquisition (DIA)-based liquid chromatography-mass spectrometry (DIA-MS) was used to identify candidate urinary biomarkers in IgAN patients with different renal interstitial fibrosis degrees. METHODS Eighteen biopsy-proven IgAN patients and six healthy controls were recruited in a discovery cohort. Interstitial fibrosis changes were evaluated according to Oxford MEST-C scores. Urinary samples were analyzed with DIA-MS to identify hub proteins. Hub proteins were then confirmed by enzyme-linked immunosorbent assay (ELISA) in a validation cohort and the associated gene mRNA expression was analyzed using public gene expression omnibus (GEO) datasets. RESULTS Complement and coagulation cascades pathway was the main KEGG pathway related to the over-expressed proteins. Fibrinogen γ-Chain (FGG) was selected as the potential urinary marker for further validation. Urinary FGG to creatinine ratio (uFGG/Cr) levels were higher in both disease controls and IgAN group than in healthy controls, but were not significantly different between IgAN and disease groups. uFGG/Cr was confirmed to be increased with the extent of renal fibrosis and presented moderate correlations with T score (r = 0.614, p < 0.01) and eGFR (r = -0.682, p < 0.01), and a mild correlation with UTP (r = 0.497, p < 0.01) in IgAN group. In disease control group, uFGG/Cr was higher in patients with T1 + 2 compared to those with T0. uFGG/Cr had a good discriminatory power to distinguish different fibrosis stages in IgAN: interstitial fibrosis ≤ 5% (minimal fibrosis) vs. interstitial fibrosis (mild fibrosis) > 5%, AUC 0.743; T0 vs. T1 + 2, AUC 0.839; T0 + 1 vs. T2, AUC 0.854. In disease control group, uFGG/Cr showed better performance of AUC than UTP between minimal and mild fibrosis (p = 0.038 for Delong's test). Moreover, GSE104954 dataset showed that FGG mRNA expression was up-regulated (fold change 1.20, p = 0.009) in tubulointerstitium of IgAN patients when compared to healthy living kidney donors. CONCLUSION Urinary FGG is associated with renal interstitial fibrosis and could be used as a noninvasive biomarker for renal fibrosis in IgAN.
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Affiliation(s)
- Jie Guan
- Peking University Ninth School of Clinical Medicine, Beijing, China
- Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University, No. 10 Tieyi Road, Haidian District, Beijing, 100038, China
- Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics, Beijing, China
- Department of Clinical Laboratory, Peking University First Hospital, Xicheng District, Beijing, China
| | - Meiling Wang
- Department of Clinical Laboratory, Peking University First Hospital, Xicheng District, Beijing, China
| | - Man Zhao
- Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University, No. 10 Tieyi Road, Haidian District, Beijing, 100038, China
- Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics, Beijing, China
| | - Wentao Ni
- Department of Pulmonary and Critical Care Medicine, Peking University People's Hospital, Xicheng District, Beijing, China
| | - Man Zhang
- Peking University Ninth School of Clinical Medicine, Beijing, China.
- Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University, No. 10 Tieyi Road, Haidian District, Beijing, 100038, China.
- Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics, Beijing, China.
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Anti-Spike Antibodies Present in the Milk of SARS-CoV-2 Vaccinated Mothers Are Complement-Activating. Int J Mol Sci 2023; 24:ijms24054395. [PMID: 36901824 PMCID: PMC10002545 DOI: 10.3390/ijms24054395] [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: 12/29/2022] [Revised: 02/02/2023] [Accepted: 02/21/2023] [Indexed: 02/25/2023] Open
Abstract
Although only 0.8-1% of SARS-CoV-2 infections are in the 0-9 age-group, pneumonia is still the leading cause of infant mortality globally. Antibodies specifically directed against SARS-CoV-2 spike protein (S) are produced during severe COVID-19 manifestations. Following vaccination, specific antibodies are also detected in the milk of breastfeeding mothers. Since antibody binding to viral antigens can trigger activation of the complement classical - pathway, we investigated antibody-dependent complement activation by anti-S immunoglobulins (Igs) present in breast milk following SARS-CoV-2 vaccination. This was in view of the fact that complement could play a fundamentally protective role against SARS-CoV-2 infection in newborns. Thus, 22 vaccinated, lactating healthcare and school workers were enrolled, and a sample of serum and milk was collected from each woman. We first tested for the presence of anti-S IgG and IgA in serum and milk of breastfeeding women by ELISA. We then measured the concentration of the first subcomponents of the three complement pathways (i.e., C1q, MBL, and C3) and the ability of anti-S Igs detected in milk to activate the complement in vitro. The current study demonstrated that vaccinated mothers have anti-S IgG in serum as well as in breast milk, which is capable of activating complement and may confer a protective benefit to breastfed newborns.
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Du Y, Cheng T, Liu C, Zhu T, Guo C, Li S, Rao X, Li J. IgA Nephropathy: Current Understanding and Perspectives on Pathogenesis and Targeted Treatment. Diagnostics (Basel) 2023; 13:diagnostics13020303. [PMID: 36673113 PMCID: PMC9857562 DOI: 10.3390/diagnostics13020303] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 01/19/2023] Open
Abstract
Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide, with varied clinical and histopathological features between individuals, particularly across races. As an autoimmune disease, IgAN arises from consequences of increased circulating levels of galactose-deficient IgA1 and mesangial deposition of IgA-containing immune complexes, which are recognized as key events in the widely accepted "multi-hit" pathogenesis of IgAN. The emerging evidence further provides insights into the role of genes, environment, mucosal immunity and complement system. These developments are paralleled by the increasing availability of diagnostic tools, potential biomarkers and therapeutic agents. In this review, we summarize current evidence and outline novel findings in the prognosis, clinical trials and translational research from the updated perspectives of IgAN pathogenesis.
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Abstract
Dysregulation and accelerated activation of the alternative pathway (AP) of complement is known to cause or accentuate several pathologic conditions in which kidney injury leads to the appearance of hematuria and proteinuria and ultimately to the development of chronic renal failure. Multiple genetic and acquired defects involving plasma- and membrane-associated proteins are probably necessary to impair the protection of host tissues and to confer a significant predisposition to AP-mediated kidney diseases. This review aims to explore how our current understanding will make it possible to identify the mechanisms that underlie AP-mediated kidney diseases and to discuss the available clinical evidence that supports complement-directed therapies. Although the value of limiting uncontrolled complement activation has long been recognized, incorporating complement-targeted treatments into clinical use has proved challenging. Availability of anti-complement therapy has dramatically transformed the outcome of atypical hemolytic uremic syndrome, one of the most severe kidney diseases. Innovative drugs that directly counteract AP dysregulation have also opened new perspectives for the management of other kidney diseases in which complement activation is involved. However, gained experience indicates that the choice of drug should be tailored to each patient's characteristics, including clinical, histologic, genetic, and biochemical parameters. Successfully treating patients requires further research in the field and close collaboration between clinicians and researchers who have special expertise in the complement system.
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Affiliation(s)
- Erica Daina
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Monica Cortinovis
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Giuseppe Remuzzi
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
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Zhang H, Deng Z, Wang Y. Molecular insight in intrarenal inflammation affecting four main types of cells in nephrons in IgA nephropathy. Front Med (Lausanne) 2023; 10:1128393. [PMID: 36968836 PMCID: PMC10034350 DOI: 10.3389/fmed.2023.1128393] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 02/13/2023] [Indexed: 03/29/2023] Open
Abstract
Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis and the leading cause of kidney failure in the world. The current widely accepted framework for its pathogenesis is the "multi-hit hypothesis." In this review, we mainly discussed the intrarenal inflammation in IgAN, which is initiated by immune complex deposition with complement molecule activation, by focusing on four main types of cells in nephrons including mesangial cells, endothelial cells, podocytes, and tubular epithelial cells (TECs). Galactose-deficient IgA1 (Gd-IgA1)-containing immune complexes deposit in the mesangium and activate complement molecules and mesangial cells. Activation of mesangial cells by Gd-IgA1 deposition with enhanced cellular proliferation, extracellular matrix (ECM) expansion, and inflammatory response plays a central role in the pathogenesis of IgAN. Regional immune complex deposition and mesangial-endothelial crosstalk result in hyperpermeability of endothelium with loss of endothelial cells and infiltration barrier proteins, and recruitment of inflammatory cells. Podocyte damage is mainly derived from mesangial-podocyte crosstalk, in which tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), renin-angiotensin-aldosterone system (RAAS), and micro-RNAs are the major players in podocyte apoptosis and disorganization of slit diaphragm (SD) related to proteinuria in patients with IgAN. In addition to filtrated proteins into tubulointerstitium and mesangial-tubular crosstalk involved in the injury of TECs, retinoic acid has been discovered innovatively participating in TEC injury.
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So BYF, Chan GCW, Yap DYH, Chan TM. The role of the complement system in primary membranous nephropathy: A narrative review in the era of new therapeutic targets. Front Immunol 2022; 13:1009864. [PMID: 36353636 PMCID: PMC9639362 DOI: 10.3389/fimmu.2022.1009864] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/12/2022] [Indexed: 11/14/2022] Open
Abstract
Primary membranous nephropathy (MN) is an important cause of nephrotic syndrome and chronic kidney disease (CKD) in the adult population. Although the discovery of different autoantibodies against glomerular/podocytic antigens have highlighted the role of B cells in the pathogenesis of MN, suboptimal response or even resistance to B cell-directed therapies occurs, suggesting that other pathophysiological mechanisms are involved in mediating podocyte injury. The complement system plays an important role in the innate immune response to infection, and dysregulation of the complement system has been observed in various kidney diseases. There is compelling evidence of complement cascade activation in primary MN, with the mannose-binding lectin (MBL) and alternative pathways particularly implicated. With appropriate validation, assays of complements and associated activation products could hold promise as adjunctive tools for non-invasive disease monitoring and prognostication. While there is growing interest to target the complement system in MN, there is concern regarding the risk of infection due to encapsulated organisms and high treatment costs, highlighting the need for clinical trials to identify patients most likely to benefit from complement-directed therapies.
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Shi DC, Feng SZ, Zhong Z, Cai L, Wang M, Fu DY, Yu XQ, Li M. Functional variant rs12614 in CFB confers a low risk of IgA nephropathy by attenuating complement alternative pathway activation in Han Chinese. Front Immunol 2022; 13:973169. [PMID: 36311737 PMCID: PMC9606215 DOI: 10.3389/fimmu.2022.973169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 09/26/2022] [Indexed: 12/14/2022] Open
Abstract
Activation of the alternative pathway (AP) of complement is thought to play an important role in Immunoglobin A nephropathy (IgAN). Our previous study showed that rs4151657 within the complement factor B (CFB) gene increased the risk of IgAN. The protein encoded by the CFB gene is an initial factor that promotes AP activation. The aim of this study was to investigate whether other variants of CFB confer susceptibility to IgAN and elucidate their potential roles in AP activation. A total of 1,350 patients with IgAN and 1,420 healthy controls were enrolled and five tag single-nucleotide polymorphisms were selected for genotyping. The levels of key AP components, such as CFB, complement factor H and complement split product C3a, were measured by enzyme-linked immunosorbent assay. Molecular docking and molecular dynamic simulation were carried out to characterize the mutation of residues in the protein structure and the dynamic properties of wide type and mutation models of CFB protein. The allele-specific effect on CFB expression and its binding affinity to C3b were investigated through cell transfection and surface plasmon resonance analysis, respectively. We found that rs12614 significantly reduced the risk of IgAN (OR = 0.69, 95% CI = 0.52-0.91, P = 0.009), and the rs12614-T (R32W mutation) was correlated with lower CFB levels, higher serum C3 level, and less mesangial C3 deposition in patients with IgAN. The structural model showed that the R32W mutation reduced the structural stability of CFB protein. Furthermore, in vitro study revealed that rs12614-T decreased the expression of CFB and reduced its binding affinity to C3b by four-fold compared with rs12614-C. In conclusion, the rs12614-T in CFB was associated with low risk of IgAN probably by attenuating AP activation.
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Affiliation(s)
- Dian-Chun Shi
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-sen University) and Guangdong Provincial Key Laboratory of Nephrology, Guangzhou, China
- Division of Nephrology, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Shao-Zhen Feng
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-sen University) and Guangdong Provincial Key Laboratory of Nephrology, Guangzhou, China
| | - Zhong Zhong
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-sen University) and Guangdong Provincial Key Laboratory of Nephrology, Guangzhou, China
| | - Lu Cai
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-sen University) and Guangdong Provincial Key Laboratory of Nephrology, Guangzhou, China
| | - Meng Wang
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-sen University) and Guangdong Provincial Key Laboratory of Nephrology, Guangzhou, China
| | - Dong-Ying Fu
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-sen University) and Guangdong Provincial Key Laboratory of Nephrology, Guangzhou, China
| | - Xue-Qing Yu
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-sen University) and Guangdong Provincial Key Laboratory of Nephrology, Guangzhou, China
- Division of Nephrology, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Ming Li
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- NHC Key Laboratory of Clinical Nephrology (Sun Yat-sen University) and Guangdong Provincial Key Laboratory of Nephrology, Guangzhou, China
- Division of Nephrology, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
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Ding L, Chen X, Cheng H, Zhang T, Li Z. Advances in IgA glycosylation and its correlation with diseases. Front Chem 2022; 10:974854. [PMID: 36238099 PMCID: PMC9552352 DOI: 10.3389/fchem.2022.974854] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 08/23/2022] [Indexed: 11/29/2022] Open
Abstract
Immunoglobulin A (IgA) is the most abundant immunoglobulin synthesized in the human body. It has the highest concentration in the mucosa and is second only to IgG in serum. IgA plays an important role in mucosal immunity, and is the predominant antibody used to protect the mucosal surface from pathogens invasion and to maintain the homeostasis of intestinal flora. Moreover, The binding IgA to the FcαRI (Fc alpha Receptor I) in soluble or aggregated form can mediate anti- or pro- inflammatory responses, respectively. IgA is also known as one of the most heavily glycosylated antibodies among human immunoglobulins. The glycosylation of IgA has been shown to have a significant effect on its immune function. Variation in the glycoform of IgA is often the main characteration of autoimmune diseases such as IgA nephropathy (IgAN), IgA vasculitis (IgAV), systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA). However, compared with the confirmed glycosylation function of IgG, the pathogenic mechanism of IgA glycosylation involved in related diseases is still unclear. This paper mainly summarizes the recent reports on IgA’s glycan structure, its function, its relationship with the occurrence and development of diseases, and the potential application of glycoengineered IgA in clinical antibody therapeutics, in order to provide a potential reference for future research in this field.
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Yoshida Y, Nishi H. The role of the complement system in kidney glomerular capillary thrombosis. Front Immunol 2022; 13:981375. [PMID: 36189215 PMCID: PMC9515535 DOI: 10.3389/fimmu.2022.981375] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/25/2022] [Indexed: 11/13/2022] Open
Abstract
The complement system is part of the innate immune system. The crucial step in activating the complement system is the generation and regulation of C3 convertase complexes, which are needed to generate opsonins that promote phagocytosis, to generate C3a that regulates inflammation, and to initiate the lytic terminal pathway through the generation and activity of C5 convertases. A growing body of evidence has highlighted the interplay between the complement system, coagulation system, platelets, neutrophils, and endothelial cells. The kidneys are highly susceptible to complement-mediated injury in several genetic, infectious, and autoimmune diseases. Atypical hemolytic uremic syndrome (aHUS) and lupus nephritis (LN) are both characterized by thrombosis in the glomerular capillaries of the kidneys. In aHUS, congenital or acquired defects in complement regulators may trigger platelet aggregation and activation, resulting in the formation of platelet-rich thrombi in the kidneys. Because glomerular vasculopathy is usually noted with immunoglobulin and complement accumulation in LN, complement-mediated activation of tissue factors could partly explain the autoimmune mechanism of thrombosis. Thus, kidney glomerular capillary thrombosis is mediated by complement dysregulation and may also be associated with complement overactivation. Further investigation is required to clarify the interaction between these vascular components and develop specific therapeutic approaches.
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40
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Mizerska-Wasiak M. How to take advantage of easily available biomarkers in patients with IgA nephropathy: IgA and C3 in serum and kidney biopsies. Pediatr Nephrol 2022; 38:1439-1448. [PMID: 35916957 DOI: 10.1007/s00467-022-05644-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 05/03/2022] [Accepted: 05/24/2022] [Indexed: 11/30/2022]
Abstract
IgA nephropathy (IgAN) is the most common glomerulonephritis worldwide. It is diagnosed based on clinical and histological features including predominant IgA deposits in kidney biopsy. The multi-hit theory, based on the production of GDIgA1 and anti-GDIgA1 antibodies, and complement activation via alternative and lectin pathways and also a genetic tendency are crucial in the pathogenesis of IgAN. The aim of the present review is to summarize the utility of routine diagnostic tests in IgA nephropathy, such as IgA and C3 in serum and kidney biopsy specimens, for predicting the disease progression. The paper also contains data on new markers used in the diagnosis and prognosis of IgA nephropathy.
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Hilhorst M, Anders HJ. IgA Nephropathy Needs a Diagnostic Marker of Immunologic Activity to Select the Right Patients for Immunotherapies. J Am Soc Nephrol 2021; 32:2982-2984. [PMID: 34789549 PMCID: PMC8638387 DOI: 10.1681/asn.2021091239] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- Marc Hilhorst
- Department of Internal Medicine, Section of Nephrology, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Hans-Joachim Anders
- Renal Division, Department of Medicine IV, University Hospital of the Ludwig Maximilian University, Munich, Germany
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Floege J, Barratt J. IgA nephropathy: a perspective for 2021. Semin Immunopathol 2021; 43:625-626. [PMID: 34705062 PMCID: PMC8551095 DOI: 10.1007/s00281-021-00890-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Jürgen Floege
- Nephrology and Clinical Immunology, University Hospital, RWTH Aachen, Aachen, Germany.
| | - Jonathan Barratt
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
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Pathogenesis of IgA Nephropathy: Current Understanding and Implications for Development of Disease-Specific Treatment. J Clin Med 2021; 10:jcm10194501. [PMID: 34640530 PMCID: PMC8509647 DOI: 10.3390/jcm10194501] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 09/22/2021] [Indexed: 12/20/2022] Open
Abstract
IgA nephropathy, initially described in 1968 as a kidney disease with glomerular “intercapillary deposits of IgA-IgG”, has no disease-specific treatment and is a common cause of kidney failure. Clinical observations and laboratory analyses suggest that IgA nephropathy is an autoimmune disease wherein the kidneys are damaged as innocent bystanders due to deposition of IgA1-IgG immune complexes from the circulation. A multi-hit hypothesis for the pathogenesis of IgA nephropathy describes four sequential steps in disease development. Specifically, patients with IgA nephropathy have elevated circulating levels of IgA1 with some O-glycans deficient in galactose (galactose-deficient IgA1) and these IgA1 glycoforms are recognized as autoantigens by unique IgG autoantibodies, resulting in formation of circulating immune complexes, some of which deposit in glomeruli and activate mesangial cells to induce kidney injury. This proposed mechanism is supported by observations that (i) glomerular immunodeposits in patients with IgA nephropathy are enriched for galactose-deficient IgA1 glycoforms and the corresponding IgG autoantibodies; (ii) circulatory levels of galactose-deficient IgA1 and IgG autoantibodies predict disease progression; and (iii) pathogenic potential of galactose-deficient IgA1 and IgG autoantibodies was demonstrated in vivo. Thus, a better understanding of the structure–function of these immunoglobulins as autoantibodies and autoantigens will enable development of disease-specific treatments.
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