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Windpessl M, Odler B, Bajema IM, Geetha D, Säemann M, Lee JM, Vaglio A, Kronbichler A. Glomerular Diseases Across Lifespan: Key Differences in Diagnostic and Therapeutic Approaches. Semin Nephrol 2023; 43:151435. [PMID: 37945450 DOI: 10.1016/j.semnephrol.2023.151435] [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] [Indexed: 11/12/2023]
Abstract
Glomerular diseases are common causes of chronic kidney disease in childhood, adolescence, and adulthood. The epidemiology of glomerular diseases differs between different age groups, with minimal change disease being the leading cause of nephrotic syndrome in childhood, while membranous nephropathy and focal segmental glomerulosclerosis are more common in adulthood. IgA vasculitis is also more common in childhood. Moreover, there is a difference in disease severity with more children presenting with a relapsing form of nephrotic syndrome and a more acute presentation of antineutrophil cytoplasmic antibody-associated vasculitis and concomitant glomerulonephritis, as highlighted by the higher percentage of cellular crescents on kidney biopsy specimens in comparison with older patients. There is also a female preponderance in antineutrophil cytoplasmic antibody-associated vasculitis and more children present with tracheobroncholaryngeal disease. This article aims to summarize differences in the presentation of different glomerular diseases that are encountered commonly by pediatric and adult nephrologists and potential differences in the management.
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Affiliation(s)
- Martin Windpessl
- Section of Nephrology, Department of Internal Medicine IV, Klinikum Wels-Grieskirchen, Wels, Austria; Medical Faculty, Johannes Kepler University Linz, Linz, Austria
| | - Balazs Odler
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom; Vasculitis and Lupus Clinic, Addenbrooke's Hospital, Cambridge, United Kingdom; Division of Nephrology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Ingeborg M Bajema
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands; Department of Pathology and Medical Biology, University of Groningen, University Medical Center, Groningen, The Netherlands
| | - Duvuru Geetha
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Marcus Säemann
- 6th Medical Department, Nephrology and Dialysis, Clinic Ottakring, Vienna, Austria; Sigmund Freud University, Medical School, Vienna, Austria
| | - Jiwon M Lee
- Division of Rare Disease Management, Korea Disease Control and Prevention Agency, Cheongju-si, Republic of Korea
| | - Augusto Vaglio
- Department of Biomedical Experimental and Clinical Sciences "Mario Serio", University of Firenze, Nephrology Unit, Meyer Children's Hospital, Firenze, Italy
| | - Andreas Kronbichler
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom; Vasculitis and Lupus Clinic, Addenbrooke's Hospital, Cambridge, United Kingdom; Department of Internal Medicine IV, Nephrology and Hypertension, Medical University Innsbruck, Innsbruck, Austria.
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2
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Liang KV, Ellis BK, Stokes MB, Smith RJ, Gu X, Gale DP. Hematuria and Proteinuria in a Patient With Recurrent Pulmonary Illnesses: A Quiz. Am J Kidney Dis 2022; 79:A13-A15. [DOI: 10.1053/j.ajkd.2021.10.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/30/2021] [Indexed: 11/11/2022]
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3
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Soraru J, Chakera A, Isbel N, Mallawaarachichi A, Rogers N, Trnka P, Patel C, Mallett A. The evolving role of diagnostic genomics in kidney transplantation. Kidney Int Rep 2022; 7:1758-1771. [PMID: 35967121 PMCID: PMC9366366 DOI: 10.1016/j.ekir.2022.05.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/11/2022] [Accepted: 05/16/2022] [Indexed: 11/06/2022] Open
Abstract
Monogenic forms of heritable kidney disease account for a significant proportion of chronic kidney disease (CKD) across both pediatric and adult patient populations and up to 11% of patients under 40 years reaching end-stage kidney failure (KF) and awaiting kidney transplant. Diagnostic genomics in the field of nephrology is ever evolving and now plays an important role in assessment and management of kidney transplant recipients and their related donor pairs. Genomic testing can help identify the cause of KF in kidney transplant recipients and assist in prognostication around graft survival and rate of recurrence of primary kidney disease. If a gene variant has been identified in the recipient, at-risk related donors can be assessed for the same and excluded if affected. This paper aims to address the indications for genomic testing in the context for kidney transplantation, the technologies available for testing, the conditions and groups in which testing should be most often considered, and the role for the renal genetics multidisciplinary team in this process.
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Vivarelli M, van de Kar N, Labbadia R, Diomedi-Camassei F, Thurman JM. A clinical approach to children with C3 glomerulopathy. Pediatr Nephrol 2022; 37:521-535. [PMID: 34002292 DOI: 10.1007/s00467-021-05088-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 03/28/2021] [Accepted: 04/20/2021] [Indexed: 11/28/2022]
Abstract
C3 glomerulopathy is a relatively new clinical entity that represents a challenge both to diagnose and to treat. As new therapeutic agents that act as complement inhibitors become available, many with an oral formulation, a better understanding of this disease and of the underlying complement dysregulation driving it has become increasingly useful to optimize patient care. Moreover, recent advances in research have clarified the role of complement in other glomerular diseases in which its role was less established, namely in immune-complex membranoproliferative glomerulonephritis (IC-MPGN), ANCA-vasculitis, IgA nephropathy, and idiopathic membranous nephropathy. Complement inhibitors are being studied in adult and adolescent clinical trials for these indications. This review summarizes current knowledge and future perspectives on every aspect of the diagnosis and management of C3 glomerulopathy and elucidates current understanding of the role of complement in this condition and in other glomerular diseases in children. An overview of ongoing trials involving therapeutic agents targeting complement in glomerular diseases is also provided.
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Affiliation(s)
- Marina Vivarelli
- Division of Nephrology and Dialysis, Department of Pediatric Subspecialties, Bambino Gesù Pediatric Hospital IRCCS, Piazza S Onofrio 4, 00165, Rome, Italy.
| | - Nicole van de Kar
- Department of Pediatric Nephrology, Amalia Children's Hospital, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Raffaella Labbadia
- Division of Nephrology and Dialysis, Department of Pediatric Subspecialties, Bambino Gesù Pediatric Hospital IRCCS, Piazza S Onofrio 4, 00165, Rome, Italy
| | | | - Joshua M Thurman
- Department of Medicine, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, USA
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The influences of α-hemolytic Streptococcus on class switching and complement activation of human tonsillar cells in IgA nephropathy. Immunol Res 2021; 70:86-96. [PMID: 34642907 DOI: 10.1007/s12026-021-09223-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 07/25/2021] [Indexed: 10/20/2022]
Abstract
While β-hemolytic streptococcus (β-HS) infections are known to predispose patients to acute poststreptococcal glomerulonephritis, there is evidence that implicates α-hemolytic streptococcus (α-HS) in IgA nephropathy (IgAN). The alternative pathway of the complement system has also been implicated in IgAN. We aimed to explore the association between α-HS and complement activation in human tonsillar mononuclear cells (TMCs) in IgAN. In our study, α-HS induced higher IgA levels than IgG levels, while β-HS increased higher IgG levels than IgA levels with more activation-induced cytidine deaminase, in TMCs in the IgAN group. Aberrant IgA1 O-glycosylation levels were higher in IgAN patients with α-HS. C3 and C3b expression was decreased in IgAN patients, but in chronic tonsillitis control patients, the expression decreased only after stimulation with β-HS. Complement factor B and H (CFH) mRNA increased, but the CFH concentration in culture supernatants decreased with α-HS. The percentage of CD19 + CD35 + cells/complement receptor 1 (CR1) decreased with α-HS more than with β-HS, while CD19 + CD21 + cells/complement receptor 2 (CR2) increased more with β-HS than with α-HS. The component nephritis-associated plasmin receptor (NAPlr) of α-HS was not detected on tonsillar or kidney tissues in IgAN patients and was positive on cultured TMCs and mesangial cells. We concluded that α-HS induced the secretion of aberrantly O-glycosylated IgA while decreasing the levels of the inhibitory factor CFH in culture supernatants and CR1 + B cells. These findings provide testable mechanisms that relate α-HS infection to abnormal mucosal responses involving the alternative complement pathway in IgAN.
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Fernandez-Ruiz R, Blank RB, Wu M, Belmont HM. C3 glomerulonephritis and systemic lupus erythematosus: A report of a patient treated with eculizumab and review of the literature. Lupus 2021; 30:1671-1678. [PMID: 34192954 DOI: 10.1177/09612033211027938] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
INTRODUCTION Activation of the complement pathway by immune complexes is a key feature of systemic lupus erythematosus (SLE) and SLE glomerulonephritis, which translates into low levels of C3 and C4 during active disease. C3 glomerulonephritis (C3GN) is part of a broader group of rare renal diseases, the C3 glomerulopathies, characterized by prominent C3 accumulation in the glomeruli with minimal to no immunoglobulin (Ig) deposition secondary to dysregulation of the alternative pathway of the complement system. Distinguishing lupus nephritis from other complement-mediated kidney disorders, including C3GN, represents a diagnostic challenge with potential therapeutic implications. METHODS We report an unusual case of a 55-year-old woman with SLE and previous biopsy-proven class IV lupus nephritis, subsequently diagnosed with C3GN. Furthermore, we review the available literature published from January 2010-March 2021 on the clinical features and management of C3GN in the setting of SLE. RESULTS In addition to our case, very few reports exist in the literature regarding C3GN in association with SLE. The underlying pathogenic mechanism of C3GN consists of dysregulation of the alternative pathway of the complement system, either due to genetic variation in complement-related genes or to acquired autoantibodies targeting C3 or C5 convertases; the latter mechanism could explain the occurrence of C3GN in the setting of autoimmune diseases, although it was not definitively identified in our patient or others with SLE. Similar to some of the previous reports, after suboptimal renal response on mycophenolate mofetil and rituximab, our patient has been successfully treated with eculizumab, thus far with >50% improvement in proteinuria. CONCLUSIONS C3GN represents an additional mechanism of renal injury in SLE mediated by alternative complement pathway dysregulation. Although rare, patients with SLE and persistent proteinuria with very low C3 would benefit from expedited renal biopsy to evaluate for C3GN as well as genetic testing, since this entity could require a different therapeutic approach.
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Affiliation(s)
- Ruth Fernandez-Ruiz
- Division of Rheumatology, New York University Grossman School of Medicine, New York, USA
| | - Rebecca B Blank
- Division of Rheumatology, New York University Grossman School of Medicine, New York, USA
| | - Ming Wu
- Department of Pathology, New York University Grossman School of Medicine, New York, USA
| | - H Michael Belmont
- Division of Rheumatology, New York University Grossman School of Medicine, New York, USA
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Ding Y, Tang X, Du Y, Chen H, Yu D, Zhu B, Yuan B. Co-existence of Alport syndrome and C3 glomerulonephritis in a proband with family history. Eur J Med Res 2021; 26:71. [PMID: 34238373 PMCID: PMC8265006 DOI: 10.1186/s40001-021-00543-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 06/28/2021] [Indexed: 01/07/2023] Open
Abstract
Background Alport syndrome and C3 glomerulonephritis (C3GN) are rare kidney diseases, frequently responsible for familial haematuria, proteinuria, and renal impairment. With the rapid development of molecular genetic testing, Alport syndrome causes have been restricted mostly to variants in the COL4A5 or COL4A3/COL4A4 genes. Moreover, a broad range of genetic contributors in the complement and complement-regulating proteins are definitely implicated in the pathogenesis of C3GN. Methods We sought a family with persistent microscopic haematuria associated with renal failure. Clinicopathologic and follow-up data were obtained, and molecular genetic testing was used to screen for pathogenic variants. Results We describe a three-generation family with Alport syndrome showing a dominant maternal inheritance. Notably, renal biopsy showed the concurrent histological evidence of C3GN in the proband harbouring an uncommon heterozygous variation in CFHR5, c.508G > A. The alteration leads to replacement of a highly conserved residue at position 170 of the β-strand subunit of CFHR5 (p.Val170Met). In silico analysis showed that the variation was predicted to deregulate complement activation by altering the structural properties and enhancing C3b binding capacity to compete with Complement Factor H (CFH), which was in line with experimental data previously published. Conclusions The comorbidity findings between Alport syndrome and C3GN indicate an underlying overlap and require further study. Supplementary Information The online version contains supplementary material available at 10.1186/s40001-021-00543-5.
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Affiliation(s)
- Yin Ding
- Department of Nephrology (Key Laboratory of Management of Kidney Disease in Zhejiang Province), Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Tiyuchang Road 453, Hangzhou, 310007, People's Republic of China
| | - Xuanli Tang
- Department of Nephrology (Key Laboratory of Management of Kidney Disease in Zhejiang Province), Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Tiyuchang Road 453, Hangzhou, 310007, People's Republic of China
| | - Yuanyuan Du
- Department of Nephrology (Key Laboratory of Management of Kidney Disease in Zhejiang Province), Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Tiyuchang Road 453, Hangzhou, 310007, People's Republic of China
| | - Hongyu Chen
- Department of Nephrology (Key Laboratory of Management of Kidney Disease in Zhejiang Province), Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Tiyuchang Road 453, Hangzhou, 310007, People's Republic of China
| | - Dongrong Yu
- Department of Nephrology (Key Laboratory of Management of Kidney Disease in Zhejiang Province), Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Tiyuchang Road 453, Hangzhou, 310007, People's Republic of China
| | - Bin Zhu
- Department of Nephrology (Key Laboratory of Management of Kidney Disease in Zhejiang Province), Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Tiyuchang Road 453, Hangzhou, 310007, People's Republic of China
| | - Bohan Yuan
- Department of Nephrology (Key Laboratory of Management of Kidney Disease in Zhejiang Province), Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Tiyuchang Road 453, Hangzhou, 310007, People's Republic of China.
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8
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Gain-of-function factor H-related 5 protein impairs glomerular complement regulation resulting in kidney damage. Proc Natl Acad Sci U S A 2021; 118:2022722118. [PMID: 33753502 PMCID: PMC8020653 DOI: 10.1073/pnas.2022722118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The complement system is integral to innate immunity and host defense. However, inappropriate activation causes host tissue damage and disease. In health, this is prevented by a complex protein network that includes the factor H proteins. Understanding control of complement is critical to treat complement-mediated disease. We demonstrate that a gain-of-function mutant factor H–related 5 protein (FHR5) results in glomerular damage. The mutant interfered with complement regulation within the kidney, resulting in complement accumulation within glomeruli and kidney damage. Administration of a complement regulator with enhanced surface regulatory activity reduced mutant-associated glomerular complement. FHR5 can disrupt the homeostatic regulation of complement within the kidney, and targeting FHR5 represents a way to treat some types of complement-mediated kidney injury. Genetic variation within the factor H–related (FHR) genes is associated with the complement-mediated kidney disease, C3 glomerulopathy (C3G). There is no definitive treatment for C3G, and a significant proportion of patients develop end-stage renal disease. The prototypical example is CFHR5 nephropathy, through which an internal duplication within a single CFHR5 gene generates a mutant FHR5 protein (FHR5mut) that leads to accumulation of complement C3 within glomeruli. To elucidate how abnormal FHR proteins cause C3G, we modeled CFHR5 nephropathy in mice. Animals lacking the murine factor H (FH) and FHR proteins, but coexpressing human FH and FHR5mut (hFH-FHR5mut), developed glomerular C3 deposition, whereas mice coexpressing human FH with the normal FHR5 protein (hFH-FHR5) did not. Like in patients, the FHR5mut had a dominant gain-of-function effect, and when administered in hFH-FHR5 mice, it triggered C3 deposition. Importantly, adeno-associated virus vector-delivered homodimeric mini-FH, a molecule with superior surface C3 binding compared to FH, reduced glomerular C3 deposition in the presence of the FHR5mut. Our data demonstrate that FHR5mut causes C3G by disrupting the homeostatic regulation of complement within the kidney and is directly pathogenic in C3G. These results support the use of FH-derived molecules with enhanced C3 binding for treating C3G associated with abnormal FHR proteins. They also suggest that targeting FHR5 represents a way to treat complement-mediated kidney injury.
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Kadkhodayi-Kholghi N, Bhatt JS, Gor J, McDermott LC, Gale DP, Perkins SJ. The solution structure of the complement deregulator FHR5 reveals a compact dimer and provides new insights into CFHR5 nephropathy. J Biol Chem 2020; 295:16342-16358. [PMID: 32928961 PMCID: PMC7705313 DOI: 10.1074/jbc.ra120.015132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/06/2020] [Indexed: 11/06/2022] Open
Abstract
The human complement Factor H-related 5 protein (FHR5) antagonizes the main circulating complement regulator Factor H, resulting in the deregulation of complement activation. FHR5 normally contains nine short complement regulator (SCR) domains, but a FHR5 mutant has been identified with a duplicated N-terminal SCR-1/2 domain pair that causes CFHR5 nephropathy. To understand how this duplication causes disease, we characterized the solution structure of native FHR5 by analytical ultracentrifugation and small-angle X-ray scattering. Sedimentation velocity and X-ray scattering indicated that FHR5 was dimeric, with a radius of gyration (Rg ) of 5.5 ± 0.2 nm and a maximum protein length of 20 nm for its 18 domains. This result indicated that FHR5 was even more compact than the main regulator Factor H, which showed an overall length of 26-29 nm for its 20 SCR domains. Atomistic modeling for FHR5 generated a library of 250,000 physically realistic trial arrangements of SCR domains for scattering curve fits. Only compact domain structures in this library fit well to the scattering data, and these structures readily accommodated the extra SCR-1/2 domain pair present in CFHR5 nephropathy. This model indicated that mutant FHR5 can form oligomers that possess additional binding sites for C3b in FHR5. We conclude that the deregulation of complement regulation by the FHR5 mutant can be rationalized by the enhanced binding of FHR5 oligomers to C3b deposited on host cell surfaces. Our FHR5 structures thus explained key features of the mechanism and pathology of CFHR5 nephropathy.
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Affiliation(s)
- Nilufar Kadkhodayi-Kholghi
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Jayesh S Bhatt
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Jayesh Gor
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | | | - Daniel P Gale
- UCL Department of Renal Medicine, Royal Free Hospital, University College London, London, United Kingdom
| | - Stephen J Perkins
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom.
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10
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Complement activity is regulated in C3 glomerulopathy by IgG-factor H fusion proteins with and without properdin targeting domains. Kidney Int 2020; 99:396-404. [PMID: 33129896 PMCID: PMC7863913 DOI: 10.1016/j.kint.2020.09.028] [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: 04/17/2020] [Revised: 09/11/2020] [Accepted: 09/17/2020] [Indexed: 11/29/2022]
Abstract
C3 glomerulopathy is characterized by accumulation of complement C3 within glomeruli. Causes include, but are not limited to, abnormalities in factor H, the major negative regulator of the complement alternative pathway. Factor H-deficient (Cfh-/-) mice develop C3 glomerulopathy together with a reduction in plasma C3 levels. Using this model, we assessed the efficacy of two fusion proteins containing the factor H alternative pathway regulatory domains (FH1-5) linked to either a non-targeting mouse immunoglobulin (IgG-FH1-5) or to an anti-mouse properdin antibody (Anti-P-FH1-5). Both proteins increased plasma C3 and reduced glomerular C3 deposition to an equivalent extent, suggesting that properdin-targeting was not required for FH1-5 to alter C3 activation in either plasma or glomeruli. Following IgG-FH1-5 administration, plasma C3 levels temporally correlated with changes in factor B levels whereas plasma C5 levels correlated with changes in plasma properdin levels. Notably, the increases in plasma C5 and properdin levels persisted for longer than the increases in C3 and factor B. In Cfh-/- mice IgG-FH1-5 reduced kidney injury during accelerated serum nephrotoxic nephritis. Thus, our data demonstrate that IgG-FH1-5 restored circulating alternative pathway activity and reduced glomerular C3 deposition in Cfh-/- mice and that plasma properdin levels are a sensitive marker of C5 convertase activity in factor H deficiency. The immunoglobulin conjugated FH1-5 protein, through its comparatively long plasma half-life, may be a potential therapy for C3 glomerulopathy.
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Perkins SJ. Genetic and Protein Structural Evaluation of Atypical Hemolytic Uremic Syndrome and C3 Glomerulopathy. Adv Chronic Kidney Dis 2020; 27:120-127.e4. [PMID: 32553244 DOI: 10.1053/j.ackd.2020.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/26/2020] [Accepted: 03/03/2020] [Indexed: 02/06/2023]
Abstract
Atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy (C3G) are associated with loss of regulation of the alternative pathway of complement and its resulting overactivation. As rare diseases, genetic variants leading to aHUS and C3G were previously analysed in relatively low patient numbers. To improve this analysis, data were pooled from six centres. Totals of 610 rare variants for aHUS and 82 for C3G were presented in an interactive database for 13 genes. Using allele frequency comparisons with the Exome Aggregation Consortium as a reference genome, the patients with aHUS showed significantly more protein-altering ultrarare variants (allele frequency <0.01%) in five genes CFH, CFI, CD46, C3, and DGKE. In patients with C3G, the corresponding association was only found for C3 and CFH. Protein structure analyses of these five proteins showed distinct differences in the positioning of these variants in C3 and FH. For aHUS, variants were clustered at the C-terminus of FH and implicated changes in the binding of FH to host cell surfaces. For C3G, variants were clustered at the N-terminal C3b binding site of FH and implicated changes in the fluid-phase regulation of C3b. We discuss the utility of the Web database as a patient resource for clinicians.
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12
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Zipfel PF, Wiech T, Stea ED, Skerka C. CFHR Gene Variations Provide Insights in the Pathogenesis of the Kidney Diseases Atypical Hemolytic Uremic Syndrome and C3 Glomerulopathy. J Am Soc Nephrol 2020; 31:241-256. [PMID: 31980588 PMCID: PMC7003313 DOI: 10.1681/asn.2019050515] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Sequence and copy number variations in the human CFHR-Factor H gene cluster comprising the complement genes CFHR1, CFHR2, CFHR3, CFHR4, CFHR5, and Factor H are linked to the human kidney diseases atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy. Distinct genetic and chromosomal alterations, deletions, or duplications generate hybrid or mutant CFHR genes, as well as hybrid CFHR-Factor H genes, and alter the FHR and Factor H plasma repertoire. A clear association between the genetic modifications and the pathologic outcome is emerging: CFHR1, CFHR3, and Factor H gene alterations combined with intact CFHR2, CFHR4, and CFHR5 genes are reported in atypical hemolytic uremic syndrome. But alterations in each of the five CFHR genes in the context of an intact Factor H gene are described in C3 glomerulopathy. These genetic modifications influence complement function and the interplay of the five FHR proteins with each other and with Factor H. Understanding how mutant or hybrid FHR proteins, Factor H::FHR hybrid proteins, and altered Factor H, FHR plasma profiles cause pathology is of high interest for diagnosis and therapy.
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Affiliation(s)
- Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany;
- Institute of Microbiology, Friedrich-Schiller-University, Jena, Germany; and
| | - Thorsten Wiech
- Section of Nephropathology, Institute of Pathology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Emma D Stea
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
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13
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Schena FP, Esposito P, Rossini M. A Narrative Review on C3 Glomerulopathy: A Rare Renal Disease. Int J Mol Sci 2020; 21:ijms21020525. [PMID: 31947692 PMCID: PMC7013756 DOI: 10.3390/ijms21020525] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 02/07/2023] Open
Abstract
In April 2012, a group of nephrologists organized a consensus conference in Cambridge (UK) on type II membranoproliferative glomerulonephritis and decided to use a new terminology, "C3 glomerulopathy" (C3 GP). Further knowledge on the complement system and on kidney biopsy contributed toward distinguishing this disease into three subgroups: dense deposit disease (DDD), C3 glomerulonephritis (C3 GN), and the CFHR5 nephropathy. The persistent presence of microhematuria with or without light or heavy proteinuria after an infection episode suggests the potential onset of C3 GP. These nephritides are characterized by abnormal activation of the complement alternative pathway, abnormal deposition of C3 in the glomeruli, and progression of renal damage to end-stage kidney disease. The diagnosis is based on studying the complement system, relative genetics, and kidney biopsies. The treatment gap derives from the absence of a robust understanding of their natural outcome. Therefore, a specific treatment for the different types of C3 GP has not been established. Recommendations have been obtained from case series and observational studies because no randomized clinical trials have been conducted. Current treatment is based on corticosteroids and antiproliferative drugs (cyclophosphamide, mycophenolate mofetil), monoclonal antibodies (rituximab) or complement inhibitors (eculizumab). In some cases, it is suggested to include sessions of plasma exchange.
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Affiliation(s)
- Francesco Paolo Schena
- Department of Emergency and Organ Transplantation, Renal Unit, University of Bari, 70124 Bari, Italy;
- Schena Foundation, European Center for the Study of Renal Diseases, 70010 Valenzano, Italy
- Correspondence:
| | - Pasquale Esposito
- Department of Internal Medicine, Division of Nephrology, Dialysis and Transplantation, University of Genoa and IRCCS Ospedale Policlinico San Martino, 16132 Genova, Italy;
| | - Michele Rossini
- Department of Emergency and Organ Transplantation, Renal Unit, University of Bari, 70124 Bari, Italy;
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14
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Kumar A, Ramachandran R, Rawat A, Das R, Rayat CS, Kenwar DB, Sharma A, Gupta KL, Nada R. Poor allograft outcome in Indian patients with post-transplant C3 glomerulopathy. Clin Kidney J 2019; 14:291-300. [PMID: 33564431 PMCID: PMC7857824 DOI: 10.1093/ckj/sfz135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 09/07/2019] [Indexed: 11/12/2022] Open
Abstract
Background Complement 3 glomerulopathy (C3G) results from dysfunction of the alternative complement pathway (ACP). No data are available on post-transplant C3G in South Asia. Methods In this study, renal allograft biopsies of C3G patients performed from 2012 to 2017 were analysed for ACP functional assay (APFA), serum complement levels, complement factor H (CFH), complement factor B (CFB) and autoantibodies to CFH and CFB. Limited genetic screening for CFH/CFHR5 genes was carried out. All study patients were also followed up. Results A total of 21 cases of C3G were included, of which 11 had native C3G disease (that is, recurrent C3G). Of these 11 recurrent cases, 7 presented with allograft dysfunction and 4 with proteinuria and renal dysfunction. Early post-transplant recurrence (<1 month) was noted in six patients, whereas recurrence in five patients occurred within 8–17 months of transplant. Biopsies showed mild focal mesangial expansion with or without endocapillary proliferation and thrombotic microangiopathy. Rejection was also noted in six patients. APFA/C3 levels were low in all cases. Serum CFH levels were low [dense deposit disease (DDD), 44%; C3 glomerulonephritis (C3GN), 25%], whereas CFB levels were normal. Autoantibodies to CFH, CFB and C3 nephritic factor were present in 11, 0 and 44% of DDD cases, respectively, and in 17, 17 and 33% of C3GN cases, respectively. Genetic analysis revealed only non-pathogenic CFH gene variants (93%). No novel mutation was found. At follow-up (140 months), stable graft was noted in 28% of cases, progressive renal failure in 19%, graft loss in 34%, and 19% of patients died. Conclusion Post-transplant C3G can present with graft dysfunction and/or proteinuria. Subtle histological findings demand careful interpretation of immunofluorescence results. Autoantibodies to complement pathway regulatory proteins are common, and no novel mutation has been found from limited genetic workup. Clinical outcome is poor.
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Affiliation(s)
- Ashwani Kumar
- Department of Histopathology, PGIMER, Chandigarh, India
| | | | - Amit Rawat
- Department of Pediatrics, PGIMER, Chandigarh, India
| | - Reena Das
- Department of Hematology, PGIMER, Chandigarh, India
| | | | | | - Ashish Sharma
- Department of Transplant Surgery, PGIMER, Chandigarh, India
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15
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Frangou E, Varnavidou-Nicolaidou A, Petousis P, Soloukides A, Theophanous E, Savva I, Michael N, Toumasi E, Georgiou D, Stylianou G, Mean R, Anastasiadou N, Athanasiou Y, Zavros M, Kyriacou K, Deltas C, Hadjianastassiou V. Clinical course and outcome after kidney transplantation in patients with C3 glomerulonephritis due to CFHR5 nephropathy. Nephrol Dial Transplant 2019; 34:1780-1788. [PMID: 30844074 DOI: 10.1093/ndt/gfz021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 01/17/2019] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Complement factor H-related protein 5 (CFHR5) nephropathy is an inherited renal disease characterized by microscopic and synpharyngitic macroscopic haematuria, C3 glomerulonephritis and renal failure. It is caused by an internal duplication of exons 2-3 within the CFHR5 gene resulting in dysregulation of the alternative complement pathway. The clinical characteristics and outcomes of transplanted patients with this rare familial nephropathy remain unknown. METHODS This is a retrospective case series study of 17 kidney transplant patients with the established founder mutation, followed-up over a span of 30 years. RESULTS The mean (±SD) age of patients at the time of the study and at transplantation was 58.6 ± 9.9 and 46.7 ± 8.8 years, respectively. The 10- and 15-year patient survival rates were 100 and 77.8%, respectively. Proteinuria was present in 33.3% and microscopic haematuria in 58.3% of patients with a functional graft. Serum complement levels were normal in all. 'Confirmed' and 'likely' recurrence of CFHR5 nephropathy were 16.6 and 52.9%, respectively; however, 76.5% of patients had a functional graft after a median of 120 months post-transplantation. Total recurrence was not associated with graft loss (P = 0.171), but was associated with the presence of microscopic haematuria (P = 0.001) and proteinuria (P = 0.018). Graft loss was associated with the presence of proteinuria (P = 0.025). CONCLUSIONS We describe for the first time the clinical characteristics and outcome of patients with CFHR5 nephropathy post-transplantation. Despite the recurrence of CFHR5 nephropathy, we provide evidence for a long-term favourable outcome and support the continued provision of kidney transplantation as a renal replacement option in patients with CFHR5 nephropathy.
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Affiliation(s)
- Eleni Frangou
- Department of Nephrology and Transplantation, Nicosia General Hospital, Nicosia, Cyprus.,Medical School, University of Cyprus, Nicosia, Cyprus.,Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | | | | | - Andreas Soloukides
- Department of Nephrology and Transplantation, Nicosia General Hospital, Nicosia, Cyprus.,Medical School, University of Cyprus, Nicosia, Cyprus
| | - Elena Theophanous
- Department of Histopathology, Nicosia General Hospital, Nicosia, Cyprus
| | - Isavella Savva
- Department of Nephrology and Transplantation, Nicosia General Hospital, Nicosia, Cyprus.,Molecular Medicine Research Center, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - Nicos Michael
- Department of Nephrology and Transplantation, Nicosia General Hospital, Nicosia, Cyprus.,Medical School, University of Nicosia, Nicosia, Cyprus
| | - Elpida Toumasi
- Department of Nephrology and Transplantation, Nicosia General Hospital, Nicosia, Cyprus.,Medical School, University of Cyprus, Nicosia, Cyprus
| | - Dora Georgiou
- Histocompatibility and Immunogenetics Laboratory, Nicosia General Hospital, Nicosia, Cyprus
| | - Galatia Stylianou
- Histocompatibility and Immunogenetics Laboratory, Nicosia General Hospital, Nicosia, Cyprus
| | - Richard Mean
- Histocompatibility and Immunogenetics Laboratory, Nicosia General Hospital, Nicosia, Cyprus
| | | | - Yiannis Athanasiou
- Department of Nephrology and Transplantation, Nicosia General Hospital, Nicosia, Cyprus.,Medical School, University of Cyprus, Nicosia, Cyprus
| | - Michalis Zavros
- Department of Nephrology and Transplantation, Nicosia General Hospital, Nicosia, Cyprus
| | - Kyriacos Kyriacou
- Department of Electron Microscopy, Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Constantinos Deltas
- Molecular Medicine Research Center, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - Vassilis Hadjianastassiou
- Department of Nephrology and Transplantation, Nicosia General Hospital, Nicosia, Cyprus.,Medical School, University of Nicosia, Nicosia, Cyprus
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16
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Complement Activation in Progression of Chronic Kidney Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1165:423-441. [PMID: 31399977 DOI: 10.1007/978-981-13-8871-2_20] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Chronic kidney disease (CKD) is a public health problem worldwide, with increasing incidence and prevalence. The mechanisms underlying the progression to end-stage renal disease (ESRD) is not fully understood. The complement system was traditionally regarded as an important part of innate immunity required for host protection against infection and for maintaining host hemostasis. However, compelling evidence from both clinical and experimental studies has strongly incriminated complement activation as a pivotal pathogenic mediator of the development of multiple renal diseases and progressive replacement of functioning nephrons by fibrosis. Both anaphylatoxins, i.e., C3a and C5a, and membrane attack complex (MAC) contribute to the damage that occurs during chronic renal progression through various mechanisms including direct proinflammatory and fibrogenic activity, chemotactic effect, activation of the renal renin-angiotensin system, and enhancement of T-cell immunity. Evolving understanding of the mechanisms of complement-mediated renal injury has led to the emergence of complement-targeting therapeutics. A variety of specific antibodies and inhibitors targeting complement components have shown efficacy in reducing disease in animal models. Moreover, building on these advances, targeting complement has gained encouraging success in treating patients with renal diseases such as atypical hemolytic uremic syndrome (aHUS). Nevertheless, it still requires a great deal of effort to develop inhibitors that can be applied to treat more patients effectively in routine clinical practice.
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17
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Smith RJH, Appel GB, Blom AM, Cook HT, D'Agati VD, Fakhouri F, Fremeaux-Bacchi V, Józsi M, Kavanagh D, Lambris JD, Noris M, Pickering MC, Remuzzi G, de Córdoba SR, Sethi S, Van der Vlag J, Zipfel PF, Nester CM. C3 glomerulopathy - understanding a rare complement-driven renal disease. Nat Rev Nephrol 2019; 15:129-143. [PMID: 30692664 PMCID: PMC6876298 DOI: 10.1038/s41581-018-0107-2] [Citation(s) in RCA: 190] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The C3 glomerulopathies are a group of rare kidney diseases characterized by complement dysregulation occurring in the fluid phase and in the glomerular microenvironment, which results in prominent complement C3 deposition in kidney biopsy samples. The two major subgroups of C3 glomerulopathy - dense deposit disease (DDD) and C3 glomerulonephritis (C3GN) - have overlapping clinical and pathological features suggestive of a disease continuum. Dysregulation of the complement alternative pathway is fundamental to the manifestations of C3 glomerulopathy, although terminal pathway dysregulation is also common. Disease is driven by acquired factors in most patients - namely, autoantibodies that target the C3 or C5 convertases. These autoantibodies drive complement dysregulation by increasing the half-life of these vital but normally short-lived enzymes. Genetic variation in complement-related genes is a less frequent cause. No disease-specific treatments are available, although immunosuppressive agents and terminal complement pathway blockers are helpful in some patients. Unfortunately, no treatment is universally effective or curative. In aggregate, the limited data on renal transplantation point to a high risk of disease recurrence (both DDD and C3GN) in allograft recipients. Clinical trials are underway to test the efficacy of several first-generation drugs that target the alternative complement pathway.
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Affiliation(s)
- Richard J H Smith
- Molecular Otolaryngology and Renal Research Laboratories and the Departments of Internal Medicine and Pediatrics (Divisions of Nephrology), Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
| | - Gerald B Appel
- Department of Nephrology, Columbia University, New York, NY, USA
| | - Anna M Blom
- Department of Translational Medicine, Lund University, Malmö, Sweden
| | - H Terence Cook
- Centre for Inflammatory Disease, Imperial College London, London, UK
| | - Vivette D D'Agati
- Department of Pathology, Renal Pathology Laboratory, Columbia University Medical Center, New York, NY, USA
| | - Fadi Fakhouri
- Department of Nephrology and Immunology, Centre Hospitalier et Universitaire de Nantes, Nantes, France
| | - Véronique Fremeaux-Bacchi
- Service de Néphrologie-Transplantation Adulte, Hôpital Necker-Enfants Malades, Université Paris Descartes, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Mihály Józsi
- Complement Research Group, Department of Immunology, ELTE Eötvös Loránd University and the MTA-SE Research Group of Immunology and Haematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - David Kavanagh
- Newcastle University, Institute of Genetic Medicine, International Centre for Life, Central Parkway, Newcastle upon Tyne, UK
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Marina Noris
- Istituto di Ricerche Farmacologiche (IRCCS) 'Mario Negri', Clinical Research Centre for Rare Diseases 'Aldo e Cele Daccò', Ranica, Bergamo, Italy
| | | | - Giuseppe Remuzzi
- Istituto di Ricerche Farmacologiche (IRCCS) 'Mario Negri', Clinical Research Centre for Rare Diseases 'Aldo e Cele Daccò', Ranica, Bergamo, Italy
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
- Unit of Nephrology and Dialysis, Azienda Socio-Sanitaria Territoriale (ASST) Papa Giovanni XXIII, Bergamo, Italy
| | - Santiago Rodriguez de Córdoba
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas and Centro de Investigación Biomédica en Enfermedades Raras, Madrid, Spain
| | - Sanjeev Sethi
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Johan Van der Vlag
- Department of Nephrology, Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Peter F Zipfel
- Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
- Friedrich Schiller University, Jena, Germany
| | - Carla M Nester
- Molecular Otolaryngology and Renal Research Laboratories and the Departments of Internal Medicine and Pediatrics (Divisions of Nephrology), Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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18
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Ng MSY, McClymont K, McCallum N, Dua R, Holman K, Bennetts B, Ho G, Patel C, Mallett AJ. CFHR5 Nephropathy in a Greek-Cypriot Australian Family: Ancestry-Informed Precision Medicine. Kidney Int Rep 2018; 3:1222-1228. [PMID: 30197990 PMCID: PMC6127413 DOI: 10.1016/j.ekir.2018.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- Monica S Y Ng
- Kidney Health Service, Royal Brisbane and Women's Hospital, Brisbane, Australia.,Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - Kelly McClymont
- Department of Histopathology, Sullivan Nicolaides Pathology, Brisbane, Australia
| | - Naomi McCallum
- Electron Microscopy Unit, Pathology Queensland, Royal Brisbane & Women's Hospital, Brisbane, Australia
| | - Rahul Dua
- Mater Private Hospital, Townsville, Australia
| | - Katherine Holman
- Department of Molecular Genetics, The Children's Hospital at Westmead, Sydney, Australia
| | - Bruce Bennetts
- Department of Molecular Genetics, The Children's Hospital at Westmead, Sydney, Australia.,Disciplines of Genetic Medicine and Paediatrics and Child Health, The University of Sydney, Sydney, Australia
| | - Gladys Ho
- Department of Molecular Genetics, The Children's Hospital at Westmead, Sydney, Australia
| | - Chirag Patel
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Brisbane, Australia
| | - Andrew J Mallett
- Kidney Health Service, Royal Brisbane and Women's Hospital, Brisbane, Australia.,Faculty of Medicine, The University of Queensland, Brisbane, Australia
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19
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Sánchez-Corral P, Pouw RB, López-Trascasa M, Józsi M. Self-Damage Caused by Dysregulation of the Complement Alternative Pathway: Relevance of the Factor H Protein Family. Front Immunol 2018; 9:1607. [PMID: 30050540 PMCID: PMC6052053 DOI: 10.3389/fimmu.2018.01607] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 06/28/2018] [Indexed: 12/13/2022] Open
Abstract
The alternative pathway is a continuously active surveillance arm of the complement system, and it can also enhance complement activation initiated by the classical and the lectin pathways. Various membrane-bound and plasma regulatory proteins control the activation of the potentially deleterious complement system. Among the regulators, the plasma glycoprotein factor H (FH) is the main inhibitor of the alternative pathway and its powerful amplification loop. FH belongs to a protein family that also includes FH-like protein 1 and five factor H-related (FHR-1 to FHR-5) proteins. Genetic variants and abnormal rearrangements involving the FH protein family have been linked to numerous systemic and organ-specific diseases, including age-related macular degeneration, and the renal pathologies atypical hemolytic uremic syndrome, C3 glomerulopathies, and IgA nephropathy. This review covers the known and recently emerged ligands and interactions of the human FH family proteins associated with disease and discuss the very recent experimental data that suggest FH-antagonistic and complement-activating functions for the FHR proteins.
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Affiliation(s)
- Pilar Sánchez-Corral
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Center for Biomedical Network Research on Rare Diseases (CIBERER), Madrid, Spain
| | - Richard B Pouw
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Margarita López-Trascasa
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Center for Biomedical Network Research on Rare Diseases (CIBERER), Madrid, Spain.,Department of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
| | - Mihály Józsi
- Complement Research Group, Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary.,MTA-SE Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
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20
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Goicoechea de Jorge E, López Lera A, Bayarri-Olmos R, Yebenes H, Lopez-Trascasa M, Rodríguez de Córdoba S. Common and rare genetic variants of complement components in human disease. Mol Immunol 2018; 102:42-57. [PMID: 29914697 DOI: 10.1016/j.molimm.2018.06.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/06/2018] [Accepted: 06/08/2018] [Indexed: 12/21/2022]
Abstract
Genetic variability in the complement system and its association with disease has been known for more than 50 years, but only during the last decade have we begun to understand how this complement genetic variability contributes to the development of diseases. A number of reports have described important genotype-phenotype correlations that associate particular diseases with genetic variants altering specific aspects of the activation and regulation of the complement system. The detailed functional characterization of some of these genetic variants provided key insights into the pathogenic mechanisms underlying these pathologies, which is facilitating the design of specific anti-complement therapies. Importantly, these analyses have sometimes revealed unknown features of the complement proteins. As a whole, these advances have delineated the functional implications of genetic variability in the complement system, which supports the implementation of a precision medicine approach based on the complement genetic makeup of the patients. Here we provide an overview of rare complement variants and common polymorphisms associated with disease and discuss what we have learned from them.
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Affiliation(s)
- Elena Goicoechea de Jorge
- Department of Immunology, Complutense University, Madrid, Spain; Research Institute Hospital 12 de Octubre (imas12), Madrid, Spain
| | - Alberto López Lera
- Research Institute Hospital Universitario La Paz (IdiPaz), Madrid, Spain; Ciber de Enfermedades Raras, Madrid, Spain
| | - Rafael Bayarri-Olmos
- Department of Clinical Immunology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Hugo Yebenes
- Ciber de Enfermedades Raras, Madrid, Spain; Molecular Pathology and Complement Genetics Unit. Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | | | - Santiago Rodríguez de Córdoba
- Ciber de Enfermedades Raras, Madrid, Spain; Molecular Pathology and Complement Genetics Unit. Centro de Investigaciones Biológicas, CSIC, Madrid, Spain.
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21
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Voskarides K, Papagregoriou G, Hadjipanagi D, Petrou I, Savva I, Elia A, Athanasiou Y, Pastelli A, Kkolou M, Hadjigavriel M, Stavrou C, Pierides A, Deltas C. COL4A5 and LAMA5 variants co-inherited in familial hematuria: digenic inheritance or genetic modifier effect? BMC Nephrol 2018; 19:114. [PMID: 29764427 PMCID: PMC5954460 DOI: 10.1186/s12882-018-0906-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 10/25/2017] [Accepted: 01/21/2018] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND About 40-50% of patients with familial microscopic hematuria (FMH) caused by thin basement membrane nephropathy (TBMN) inherit heterozygous mutations in collagen IV genes (COL4A3, COL4A4). On long follow-up, the full phenotypic spectrum of these patients varies a lot, ranging from isolated MH or MH plus low-grade proteinuria to chronic renal failure of variable degree, including end-stage renal disease (ESRD). METHODS Here, we performed Whole Exome Sequencing (WES) in patients of six families, presenting with autosomal dominant FMH, with or without progression to proteinuria and loss of renal function, all previously found negative for severe collagen IV mutations. Hierarchical filtering of the WES data was performed, followed by mutation prediction analysis, Sanger sequencing and genetic segregation analysis. RESULTS In one family with four patients, we found evidence for the contribution of two co-inherited variants in two crucial genes expressed in the glomerular basement membrane (GBM); LAMA5-p.Pro1243Leu and COL4A5-p.Asp654Tyr. Mutations in COL4A5 cause classical X-linked Alport Syndrome, while rare mutations in the LAMA5 have been reported in patients with focal segmental glomerulosclerosis. The phenotypic spectrum of the patients includes hematuria, proteinuria, focal segmental glomerulosclerosis, loss of kidney function and renal cortical cysts. CONCLUSIONS A modifier role of LAMA5 on the background of a hypomorphic Alport syndrome causing mutation is a possible explanation of our findings. Digenic inheritance is another scenario, following the concept that mutations at both loci more accurately explain the spectrum of symptoms, but further investigation is needed under this concept. This is the third report linking a LAMA5 variant with human renal disease and expanding the spectrum of genes involved in glomerular pathologies accompanied by familial hematurias. The cystic phenotype overlaps with that of a mouse model, which carried a Lama5 hypomorphic mutation that caused severely reduced Lama5 protein levels and produced kidney cysts.
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Affiliation(s)
- Konstantinos Voskarides
- Molecular Medicine Research Center, Department of Biological Sciences, University of Cyprus, 1, University Avenue, 2109, Nicosia, Cyprus. .,Medical School, University of Cyprus, Nicosia, Cyprus.
| | - Gregory Papagregoriou
- Molecular Medicine Research Center, Department of Biological Sciences, University of Cyprus, 1, University Avenue, 2109, Nicosia, Cyprus
| | - Despina Hadjipanagi
- Molecular Medicine Research Center, Department of Biological Sciences, University of Cyprus, 1, University Avenue, 2109, Nicosia, Cyprus
| | - Ioanelli Petrou
- Molecular Medicine Research Center, Department of Biological Sciences, University of Cyprus, 1, University Avenue, 2109, Nicosia, Cyprus
| | - Isavella Savva
- Molecular Medicine Research Center, Department of Biological Sciences, University of Cyprus, 1, University Avenue, 2109, Nicosia, Cyprus
| | - Avraam Elia
- Department of Pediatric Nephrology, Archbishop Makarios III Hospital, Nicosia, Cyprus
| | | | | | - Maria Kkolou
- Department of Nephrology, Larnaca General Hospital, Larnaca, Cyprus
| | | | | | - Alkis Pierides
- Molecular Medicine Research Center, Department of Biological Sciences, University of Cyprus, 1, University Avenue, 2109, Nicosia, Cyprus.,Hippocrateon Hospital, Nicosia, Cyprus
| | - Constantinos Deltas
- Molecular Medicine Research Center, Department of Biological Sciences, University of Cyprus, 1, University Avenue, 2109, Nicosia, Cyprus. .,College of Medicine, Qatar University, Doha, Qatar.
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22
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Zhu L, Guo WY, Shi SF, Liu LJ, Lv JC, Medjeral-Thomas NR, Lomax-Browne HJ, Pickering MC, Zhang H. Circulating complement factor H-related protein 5 levels contribute to development and progression of IgA nephropathy. Kidney Int 2018; 94:150-158. [PMID: 29759419 DOI: 10.1016/j.kint.2018.02.023] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 01/19/2018] [Accepted: 02/08/2018] [Indexed: 11/25/2022]
Abstract
IgA nephropathy (IgAN) is a disease associated with activation of the complement system. But the factors influencing complement activation in IgAN are not fully understood. Complement factor H (FH) is an essential negative regulator of complement C3 activation. Complement factor H-related protein (FHR)-5 shares high sequence similarity with factor H. However, unlike factor H, on binding to activated C3 it enables further activation to proceed. Previously, we reported the contribution of rare variants of the CFHR5 gene to IgAN susceptibility. Here we compared circulating levels of FHR-5 in 1126 patients with IgAN and regular follow-up with those of 153 unrelated healthy individuals to explore the relationship of FHR-5 levels with IgAN development and progression. Circulating FHR-5 levels were significantly elevated in patients with IgAN compared to healthy individuals (median 4.55 [interquartile range 3.58 to 5.85] μg/ml vs 3.19 [interquartile range 2.55 to 3.92] μg/ml). Higher circulating FHR-5 levels were associated with a lower estimated glomerular filtration rate, hypertension, and severe Oxford-T and Oxford-C scores. High FHR-5 levels were independently and significantly associated with a risk of developing either a 30% decline in the estimated glomerular filtration rate or end-stage renal disease (hazard ratio, per standard deviation increment of natural square root transformed FHR-5 of 1.226; 95% confidence interval: 1.106-1.359). Thus, the circulating FHR-5 level is an independent risk factor for IgAN progression.
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Affiliation(s)
- Li Zhu
- Renal Division, Department of Medicine, Peking University First Hospital, China; Peking University Institute of Nephrology, China; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education of China
| | - Wei-Yi Guo
- Renal Division, Department of Medicine, Peking University First Hospital, China; Peking University Institute of Nephrology, China; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education of China
| | - Su-Fang Shi
- Renal Division, Department of Medicine, Peking University First Hospital, China; Peking University Institute of Nephrology, China; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education of China
| | - Li-Jun Liu
- Renal Division, Department of Medicine, Peking University First Hospital, China; Peking University Institute of Nephrology, China; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education of China
| | - Ji-Cheng Lv
- Renal Division, Department of Medicine, Peking University First Hospital, China; Peking University Institute of Nephrology, China; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education of China
| | | | - Hannah J Lomax-Browne
- Centre for Complement and Inflammation Research, Imperial College London, London, UK
| | - Matthew C Pickering
- Centre for Complement and Inflammation Research, Imperial College London, London, UK
| | - Hong Zhang
- Renal Division, Department of Medicine, Peking University First Hospital, China.
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23
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Avasare RS, Canetta PA, Bomback AS, Marasa M, Caliskan Y, Ozluk Y, Li Y, Gharavi AG, Appel GB. Mycophenolate Mofetil in Combination with Steroids for Treatment of C3 Glomerulopathy: A Case Series. Clin J Am Soc Nephrol 2018; 13:406-413. [PMID: 29326307 PMCID: PMC5967675 DOI: 10.2215/cjn.09080817] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 12/14/2017] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND OBJECTIVES C3 glomerulopathy is a form of complement-mediated GN. Immunosuppressive therapy may be beneficial in the treatment of C3 glomerulopathy. Mycophenolate mofetil is an attractive treatment option given its role in the treatment of other complement-mediated diseases and the results of the Spanish Group for the Study of Glomerular Diseases C3 Study. Here, we study the outcomes of patients with C3 glomerulopathy treated with steroids and mycophenolate mofetil. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We conducted a retrospective chart review of patients in the C3 glomerulopathy registry at Columbia University and identified patients treated with mycophenolate mofetil for at least 3 months and follow-up for at least 1 year. We studied clinical, histologic, and genetic data for the whole group and compared data for those who achieved complete or partial remission (responders) with those who did not achieve remission (nonresponders). We compared remission with mycophenolate mofetil with remission with other immunosuppressive regimens. RESULTS We identified 30 patients who met inclusion criteria. Median age was 25 years old (interquartile range, 18-36), median creatinine was 1.07 mg/dl (interquartile range, 0.79-1.69), and median proteinuria was 3200 mg/g creatinine (interquartile range, 1720-6759). The median follow-up time was 32 months (interquartile range, 21-68). Twenty (67%) patients were classified as responders. There were no significant differences in baseline characteristics between responders and nonresponders, although initial proteinuria was lower (median 2468 mg/g creatinine) in responders compared with nonresponders (median 5000 mg/g creatinine) and soluble membrane attack complex levels were higher in responders compared with nonresponders. For those tapered off mycophenolate mofetil, relapse rate was 50%. Genome-wide analysis on complement genes was done, and in 12 patients, we found 18 variants predicted to be damaging. None of these variants were previously reported to be pathogenic. Mycophenolate mofetil with steroids outperformed other immunosuppressive regimens. CONCLUSIONS Among patients who tolerated mycophenolate mofetil, combination therapy with steroids induced remission in 67% of this cohort. Heavier proteinuria at the start of therapy and lower soluble membrane attack complex levels were associated with treatment resistance.
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Affiliation(s)
- Rupali S. Avasare
- Division of Nephrology, Department of Medicine, Oregon Health Science University, Portland, Oregon
| | - Pietro A. Canetta
- Division of Nephrology, Department of Medicine, Columbia University Medical Center, New York, New York; and
| | - Andrew S. Bomback
- Division of Nephrology, Department of Medicine, Columbia University Medical Center, New York, New York; and
| | - Maddalena Marasa
- Division of Nephrology, Department of Medicine, Columbia University Medical Center, New York, New York; and
| | - Yasar Caliskan
- Division of Nephrology, Department of Internal Medicine and
| | - Yasemin Ozluk
- Department of Pathology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Yifu Li
- Division of Nephrology, Department of Medicine, Columbia University Medical Center, New York, New York; and
| | - Ali G. Gharavi
- Division of Nephrology, Department of Medicine, Columbia University Medical Center, New York, New York; and
| | - Gerald B. Appel
- Division of Nephrology, Department of Medicine, Columbia University Medical Center, New York, New York; and
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24
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Osborne AJ, Breno M, Borsa NG, Bu F, Frémeaux-Bacchi V, Gale DP, van den Heuvel LP, Kavanagh D, Noris M, Pinto S, Rallapalli PM, Remuzzi G, Rodríguez de Cordoba S, Ruiz A, Smith RJH, Vieira-Martins P, Volokhina E, Wilson V, Goodship THJ, Perkins SJ. Statistical Validation of Rare Complement Variants Provides Insights into the Molecular Basis of Atypical Hemolytic Uremic Syndrome and C3 Glomerulopathy. THE JOURNAL OF IMMUNOLOGY 2018; 200:2464-2478. [PMID: 29500241 DOI: 10.4049/jimmunol.1701695] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 01/31/2018] [Indexed: 01/02/2023]
Abstract
Atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy (C3G) are associated with dysregulation and overactivation of the complement alternative pathway. Typically, gene analysis for aHUS and C3G is undertaken in small patient numbers, yet it is unclear which genes most frequently predispose to aHUS or C3G. Accordingly, we performed a six-center analysis of 610 rare genetic variants in 13 mostly complement genes (CFH, CFI, CD46, C3, CFB, CFHR1, CFHR3, CFHR4, CFHR5, CFP, PLG, DGKE, and THBD) from >3500 patients with aHUS and C3G. We report 371 novel rare variants (RVs) for aHUS and 82 for C3G. Our new interactive Database of Complement Gene Variants was used to extract allele frequency data for these 13 genes using the Exome Aggregation Consortium server as the reference genome. For aHUS, significantly more protein-altering rare variation was found in five genes CFH, CFI, CD46, C3, and DGKE than in the Exome Aggregation Consortium (allele frequency < 0.01%), thus correlating these with aHUS. For C3G, an association was only found for RVs in C3 and the N-terminal C3b-binding or C-terminal nonsurface-associated regions of CFH In conclusion, the RV analyses showed nonrandom distributions over the affected proteins, and different distributions were observed between aHUS and C3G that clarify their phenotypes.
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Affiliation(s)
- Amy J Osborne
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, United Kingdom
| | - Matteo Breno
- Centro di Ricerche Cliniche per le Malattie Rare "Aldo e Cele Daccò," IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri," 24020 Ranica Bergamo, Italy
| | - Nicolo Ghiringhelli Borsa
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Fengxiao Bu
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA 52242.,Medical Genetics Center, Southwest Hospital, Chongqing 400038, China
| | - Véronique Frémeaux-Bacchi
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service d'Immunologie Biologique, 75015 Paris, France
| | - Daniel P Gale
- Centre for Nephrology, Royal Free Hospital, University College London, London NW3 2QG, United Kingdom
| | - Lambertus P van den Heuvel
- Department of Pediatric Nephrology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands.,Department of Pediatric Nephrology, Department of Growth and Regeneration, University Hospital Leuven, 3000 Leuven, Belgium
| | - David Kavanagh
- The National Renal Complement Therapeutics Centre, Newcastle upon Tyne NE1 4LP, United Kingdom.,Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, United Kingdom
| | - Marina Noris
- Centro di Ricerche Cliniche per le Malattie Rare "Aldo e Cele Daccò," IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri," 24020 Ranica Bergamo, Italy
| | - Sheila Pinto
- Department of Cellular and Molecular Medicine, Center for Biological Research and Center for Biomedical Network Research on Rare Diseases, 28040 Madrid, Spain
| | - Pavithra M Rallapalli
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, United Kingdom
| | - Giuseppe Remuzzi
- Centro di Ricerche Cliniche per le Malattie Rare "Aldo e Cele Daccò," IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri," 24020 Ranica Bergamo, Italy.,Department of Biomedical and Clinical Sciences, University of Milan, 20122 Milan, Italy; and
| | - Santiago Rodríguez de Cordoba
- Department of Cellular and Molecular Medicine, Center for Biological Research and Center for Biomedical Network Research on Rare Diseases, 28040 Madrid, Spain
| | - Angela Ruiz
- Department of Cellular and Molecular Medicine, Center for Biological Research and Center for Biomedical Network Research on Rare Diseases, 28040 Madrid, Spain
| | - Richard J H Smith
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Paula Vieira-Martins
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service d'Immunologie Biologique, 75015 Paris, France
| | - Elena Volokhina
- Department of Pediatric Nephrology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Valerie Wilson
- Northern Molecular Genetics Service, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne NE1 3BZ, United Kingdom
| | - Timothy H J Goodship
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, United Kingdom
| | - Stephen J Perkins
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, United Kingdom;
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25
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Abbas F, El Kossi M, Jin JK, Sharma A, Halawa A. Recurrence of primary glomerulonephritis: Review of the current evidence. World J Transplant 2017; 7:301-316. [PMID: 29312859 PMCID: PMC5743867 DOI: 10.5500/wjt.v7.i6.301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 09/24/2017] [Accepted: 11/22/2017] [Indexed: 02/05/2023] Open
Abstract
In view of the availability of new immunosuppression strategies, the recurrence of allograft glomerulonephritis (GN) are reported to be increasing with time post transplantation. Recent advances in understanding the pathogenesis of the GN recurrent disease provided a better chance to develop new strategies to deal with the GN recurrence. Recurrent GN diseases manifest with a variable course, stubborn behavior, and poor response to therapy. Some types of GN lead to rapid decline of kidney function resulting in a frustrating return to maintenance dialysis. This subgroup of aggressive diseases actually requires intensive efforts to ascertain their pathogenesis so that strategy could be implemented for better allograft survival. Epidemiology of native glomerulonephritis as the cause of end-stage renal failure and subsequent recurrence of individual glomerulonephritis after renal transplantation was evaluated using data from various registries, and pathogenesis of individual glomerulonephritis is discussed. The following review is aimed to define current protocols of the recurrent primary glomerulonephritis therapy.
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Affiliation(s)
- Fedaey Abbas
- Department of Nephrology, Jaber El Ahmed Military Hospital, Safat 13005, Kuwait
- Faculty of Health and Science, University of Liverpool, Institute of Learning and Teaching, School of Medicine, Liverpool L69 3GB, United Kingdom
| | - Mohsen El Kossi
- Faculty of Health and Science, University of Liverpool, Institute of Learning and Teaching, School of Medicine, Liverpool L69 3GB, United Kingdom
- Doncaster Royal Infirmary, Doncaster DN2 5LT, United Kingdom
| | - Jon Kim Jin
- Faculty of Health and Science, University of Liverpool, Institute of Learning and Teaching, School of Medicine, Liverpool L69 3GB, United Kingdom
- Nottingham Children Hospital, Nottingham NG7 2UH, United Kingdom
| | - Ajay Sharma
- Faculty of Health and Science, University of Liverpool, Institute of Learning and Teaching, School of Medicine, Liverpool L69 3GB, United Kingdom
- Royal Liverpool University Hospitals, Liverpool L7 8XP, United Kingdom
| | - Ahmed Halawa
- Faculty of Health and Science, University of Liverpool, Institute of Learning and Teaching, School of Medicine, Liverpool L69 3GB, United Kingdom
- Department of Transplantation Surgery, Sheffield Teaching Hospitals, Sheffield S5 7AU, United Kingdom
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26
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Cook HT, Pickering MC. Clusters Not Classifications: Making Sense of Complement-Mediated Kidney Injury. J Am Soc Nephrol 2017; 29:9-12. [PMID: 29229764 DOI: 10.1681/asn.2017111183] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- H Terence Cook
- Centre for Complement and Inflammation Research, Imperial College London, London, United Kingdom
| | - Matthew C Pickering
- Centre for Complement and Inflammation Research, Imperial College London, London, United Kingdom
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27
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Papazachariou L, Papagregoriou G, Hadjipanagi D, Demosthenous P, Voskarides K, Koutsofti C, Stylianou K, Ioannou P, Xydakis D, Tzanakis I, Papadaki A, Kallivretakis N, Nikolakakis N, Perysinaki G, Gale DP, Diamantopoulos A, Goudas P, Goumenos D, Soloukides A, Boletis I, Melexopoulou C, Georgaki E, Frysira E, Komianou F, Grekas D, Paliouras C, Alivanis P, Vergoulas G, Pierides A, Daphnis E, Deltas C. Frequent COL4 mutations in familial microhematuria accompanied by later-onset Alport nephropathy due to focal segmental glomerulosclerosis. Clin Genet 2017. [PMID: 28632965 DOI: 10.1111/cge.13077] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Familial microscopic hematuria (FMH) is associated with a genetically heterogeneous group of conditions including the collagen-IV nephropathies, the heritable C3/CFHR5 nephropathy and the glomerulopathy with fibronectin deposits. The clinical course varies widely, ranging from isolated benign familial hematuria to end-stage renal disease (ESRD) later in life. We investigated 24 families using next generation sequencing (NGS) for 5 genes: COL4A3, COL4A4, COL4A5, CFHR5 and FN1. In 17 families (71%), we found 15 pathogenic mutations in COL4A3/A4/A5, 9 of them novel. In 5 families patients inherited classical AS with hemizygous X-linked COL4A5 mutations. Even more patients developed later-onset Alport-related nephropathy having inherited heterozygous COL4A3/A4 mutations that cause thin basement membranes. Amongst 62 heterozygous or hemizygous patients, 8 (13%) reached ESRD, while 25% of patients with heterozygous COL4A3/A4 mutations, aged >50-years, reached ESRD. In conclusion, COL4A mutations comprise a frequent cause of FMH. Heterozygous COL4A3/A4 mutations predispose to renal function impairment, supporting that thin basement membrane nephropathy is not always benign. The molecular diagnosis is essential for differentiating the X-linked from the autosomal recessive and dominant inheritance. Finally, NGS technology is established as the gold standard for the diagnosis of FMH and associated collagen-IV glomerulopathies, frequently averting the need for invasive renal biopsies.
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Affiliation(s)
- L Papazachariou
- Molecular Medicine Research Center & Laboratory of Molecular and Medical Genetics, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - G Papagregoriou
- Molecular Medicine Research Center & Laboratory of Molecular and Medical Genetics, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - D Hadjipanagi
- Molecular Medicine Research Center & Laboratory of Molecular and Medical Genetics, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - P Demosthenous
- Molecular Medicine Research Center & Laboratory of Molecular and Medical Genetics, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - K Voskarides
- Molecular Medicine Research Center & Laboratory of Molecular and Medical Genetics, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - C Koutsofti
- Molecular Medicine Research Center & Laboratory of Molecular and Medical Genetics, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - K Stylianou
- Department of Nephrology, University of Crete-Greece, Heraklion, Greece
| | - P Ioannou
- Department of Nephrology, University of Crete-Greece, Heraklion, Greece
| | - D Xydakis
- Department of Nephrology, University of Crete-Greece, Heraklion, Greece
| | - I Tzanakis
- Department of Nephrology, General Hospital of Chania, Crete, Greece
| | - A Papadaki
- Department of Nephrology, General Hospital of Chania, Crete, Greece
| | - N Kallivretakis
- Department of Nephrology, General Hospital of Chania, Crete, Greece
| | - N Nikolakakis
- Division of Nephrology, General Hospital of Rethymno, Crete, Greece
| | - G Perysinaki
- Division of Nephrology, General Hospital of Rethymno, Crete, Greece
| | - D P Gale
- UCL Division of Medicine and Centre for Nephrology, University College London, London, UK
| | | | - P Goudas
- IATOS Dialysis Unit, Patra, Greece
| | - D Goumenos
- Department of Nephrology, Medical School, University of Patras, Patra, Greece
| | - A Soloukides
- Protypo Nefrologiko Athinon Dialysis Center, Athens, Greece
| | - I Boletis
- Department of Nephrology, Laikon Hospital, Athens, Greece
| | - C Melexopoulou
- Department of Nephrology, Laikon Hospital, Athens, Greece
| | - E Georgaki
- Pediatric Nephrology Unit, "IASO" Children's Hospital, Athens, Greece
| | - E Frysira
- Department of Pediatrics, Athens University Medical School, Agia Sophia Children's Hospital, Athens, Greece
| | - F Komianou
- Department of Medical Genetics, Athens University Medical School, Agia Sophia Children's Hospital, Athens, Greece
| | - D Grekas
- University Hospital AXEPA, Thessaloniki, Greece
| | - C Paliouras
- Department of Nephrology, General Hospital of Rhodes, Rhodes, Greece
| | - P Alivanis
- Department of Nephrology, General Hospital of Rhodes, Rhodes, Greece
| | - G Vergoulas
- Organ Transplant Unit, Hippokratio General Hospital, Thessaloniki, Greece
| | - A Pierides
- Molecular Medicine Research Center & Laboratory of Molecular and Medical Genetics, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus.,Department of Nephrology, Hippocrateon Hospital, Nicosia, Cyprus
| | - E Daphnis
- Department of Nephrology, University of Crete-Greece, Heraklion, Greece
| | - C Deltas
- Molecular Medicine Research Center & Laboratory of Molecular and Medical Genetics, Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
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28
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Medjeral-Thomas NR, Lomax-Browne HJ, Beckwith H, Willicombe M, McLean AG, Brookes P, Pusey CD, Falchi M, Cook HT, Pickering MC. Circulating complement factor H-related proteins 1 and 5 correlate with disease activity in IgA nephropathy. Kidney Int 2017; 92:942-952. [PMID: 28673452 PMCID: PMC5611987 DOI: 10.1016/j.kint.2017.03.043] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/23/2017] [Accepted: 03/30/2017] [Indexed: 12/21/2022]
Abstract
IgA nephropathy (IgAN) is a common cause of chronic kidney disease and end-stage renal failure, especially in young people. Due to a wide range of clinical outcomes and difficulty in predicting response to immunosuppression, we need to understand why and identify which patients with IgAN will develop progressive renal impairment. A deletion polymorphism affecting the genes encoding the complement factor H-related protein (FHR)-1 and FHR-3 is robustly associated with protection against IgAN. Some FHR proteins, including FHR-1 and FHR-5, antagonize the ability of complement factor H (fH), the major negative regulator of the complement alternative pathway, to inhibit complement activation on surfaces, a process termed fH deregulation. From a large cohort of patients, we demonstrated that plasma FHR-1 and the FHR-1/fH ratio were elevated in IgAN and associated with progressive disease. Plasma FHR-1 negatively correlated with eGFR but remained elevated in patients with IgAN with normal eGFR. Serum FHR5 was slightly elevated in IgAN but did not correlate with eGFR. Neither FHR5 levels nor the FHR-5/fH ratio was associated with progressive disease. However, higher serum FHR-5 levels were associated with a lack of response to immunosuppression, the presence of endocapillary hypercellularity, and histology scores of disease severity (the Oxford Classification MEST score). Thus, FHR-1 and FHR-5 have a role in IgAN disease progression.
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Affiliation(s)
| | | | - Hannah Beckwith
- Centre for Complement and Inflammation Research, Imperial College London, UK
| | - Michelle Willicombe
- Renal and Transplant Centre, Imperial College Healthcare NHS Trust, London, UK
| | - Adam G McLean
- Renal and Transplant Centre, Imperial College Healthcare NHS Trust, London, UK
| | - Paul Brookes
- Histocompatibility & Immunogenetics, Imperial College Healthcare NHS Trust, London, UK
| | - Charles D Pusey
- Renal and Vascular Inflammation Section, Imperial College London, UK
| | - Mario Falchi
- Department of Twin Research and Genetic Epidemiology, King's College London, UK
| | - H Terence Cook
- Centre for Complement and Inflammation Research, Imperial College London, UK
| | - Matthew C Pickering
- Centre for Complement and Inflammation Research, Imperial College London, UK.
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29
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A functional variant in NEPH3 gene confers high risk of renal failure in primary hematuric glomerulopathies. Evidence for predisposition to microalbuminuria in the general population. PLoS One 2017; 12:e0174274. [PMID: 28334007 PMCID: PMC5363870 DOI: 10.1371/journal.pone.0174274] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 03/06/2017] [Indexed: 01/06/2023] Open
Abstract
Background Recent data emphasize that thin basement membrane nephropathy (TBMN) should not be viewed as a form of benign familial hematuria since chronic renal failure (CRF) and even end-stage renal disease (ESRD), is a possible development for a subset of patients on long-term follow-up, through the onset of focal and segmental glomerulosclerosis (FSGS). We hypothesize that genetic modifiers may explain this variability of symptoms. Methods We looked in silico for potentially deleterious functional SNPs, using very strict criteria, in all the genes significantly expressed in the slit diaphragm (SD). Two variants were genotyped in a cohort of well-studied adult TBMN patients from 19 Greek-Cypriot families, with a homogeneous genetic background. Patients were categorized as “Severe” or “Mild”, based on the presence or not of proteinuria, CRF and ESRD. A larger pooled cohort (HEMATURIA) of 524 patients, including IgA nephropathy patients, was used for verification. Additionally, three large general population cohorts [Framingham Heart Study (FHS), KORAF4 and SAPHIR] were used to investigate if the NEPH3-V353M variant has any renal effect in the general population. Results and conclusions Genotyping for two high-scored variants in 103 TBMN adult patients with founder mutations who were classified as mildly or severely affected, pointed to an association with variant NEPH3-V353M (filtrin). This promising result prompted testing in the larger pooled cohort (HEMATURIA), indicating an association of the 353M variant with disease severity under the dominant model (p = 3.0x10-3, OR = 6.64 adjusting for gender/age; allelic association: p = 4.2x10-3 adjusting for patients’ kinships). Subsequently, genotyping 6,531 subjects of the Framingham Heart Study (FHS) revealed an association of the homozygous 353M/M genotype with microalbuminuria (p = 1.0x10-3). Two further general population cohorts, KORAF4 and SAPHIR confirmed the association, and a meta-analysis of all three cohorts (11,258 individuals) was highly significant (p = 1.3x10-5, OR = 7.46). Functional studies showed that Neph3 homodimerization and Neph3-Nephrin heterodimerization are disturbed by variant 353M. Additionally, 353M was associated with differential activation of the unfolded protein response pathway, when overexpressed in stressed cultured undifferentiated podocyte cells, thus attesting to its functional significance. Genetics and functional studies support a “rare variant-strong effect” role for NEPH3-V353M, by exerting a negative modifier effect on primary glomerular hematuria. Additionally, genetics studies provide evidence for a role in predisposing homozygous subjects of the general population to micro-albuminuria.
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30
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Kousios A. Does complement Factor H-Related protein 5 Nephropathy (Troodos Nephropathy) protect from rickettsial infections? Med Hypotheses 2017; 98:76-80. [DOI: 10.1016/j.mehy.2016.11.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 11/25/2016] [Indexed: 10/20/2022]
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31
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Familial hematuria: A review. Medicina (B Aires) 2017; 53:1-10. [DOI: 10.1016/j.medici.2017.01.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 12/23/2016] [Accepted: 01/16/2017] [Indexed: 12/17/2022] Open
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32
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Salvadori M, Bertoni E. Complement related kidney diseases: Recurrence after transplantation. World J Transplant 2016; 6:632-645. [PMID: 28058212 PMCID: PMC5175220 DOI: 10.5500/wjt.v6.i4.632] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 10/26/2016] [Accepted: 11/17/2016] [Indexed: 02/05/2023] Open
Abstract
The recurrence of renal disease after renal transplantation is becoming one of the main causes of graft loss after kidney transplantation. This principally concerns some of the original diseases as the atypical hemolytic uremic syndrome (HUS), the membranoproliferative glomerulonephritis (MPGN), in particular the MPGN now called C3 glomerulopathy. Both this groups of renal diseases are characterized by congenital (genetic) or acquired (auto-antibodies) modifications of the alternative pathway of complement. These abnormalities often remain after transplantation because they are constitutional and poorly influenced by the immunosuppression. This fact justifies the high recurrence rate of these diseases. Early diagnosis of recurrence is essential for an optimal therapeutically approach, whenever possible. Patients affected by end stage renal disease due to C3 glomerulopathies or to atypical HUS, may be transplanted with extreme caution. Living donor donation from relatives is not recommended because members of the same family may be affected by the same gene mutation. Different therapeutically approaches have been attempted either for recurrence prevention and treatment. The most promising approach is represented by complement inhibitors. Eculizumab, a monoclonal antibody against C5 convertase is the most promising drug, even if to date is not known how long the therapy should be continued and which are the best dosing. These facts face the high costs of the treatment. Eculizumab resistant patients have been described. They could benefit by a C3 convertase inhibitor, but this class of drugs is by now the object of randomized controlled trials.
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33
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Goodship THJ, Cook HT, Fakhouri F, Fervenza FC, Frémeaux-Bacchi V, Kavanagh D, Nester CM, Noris M, Pickering MC, Rodríguez de Córdoba S, Roumenina LT, Sethi S, Smith RJH. Atypical hemolytic uremic syndrome and C3 glomerulopathy: conclusions from a "Kidney Disease: Improving Global Outcomes" (KDIGO) Controversies Conference. Kidney Int 2016; 91:539-551. [PMID: 27989322 DOI: 10.1016/j.kint.2016.10.005] [Citation(s) in RCA: 420] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/10/2016] [Accepted: 10/20/2016] [Indexed: 02/06/2023]
Abstract
In both atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy (C3G) complement plays a primary role in disease pathogenesis. Herein we report the outcome of a 2015 Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference where key issues in the management of these 2 diseases were considered by a global panel of experts. Areas addressed included renal pathology, clinical phenotype and assessment, genetic drivers of disease, acquired drivers of disease, and treatment strategies. In order to help guide clinicians who are caring for such patients, recommendations for best treatment strategies were discussed at length, providing the evidence base underpinning current treatment options. Knowledge gaps were identified and a prioritized research agenda was proposed to resolve outstanding controversial issues.
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Affiliation(s)
| | - H Terence Cook
- Centre for Complement and Inflammation Research, Department of Medicine, Imperial College Hammersmith Campus, London, UK
| | - Fadi Fakhouri
- INSERM, UMR-S 1064, and Department of Nephrology and Immunology, CHU de Nantes, Nantes, France
| | - Fernando C Fervenza
- Department of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | | | - David Kavanagh
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Carla M Nester
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA; Division of Nephrology, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Marina Noris
- IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri," Clinical Research Center for Rare Diseases "Aldo e Cele Daccò," Ranica, Bergamo, Italy
| | - Matthew C Pickering
- Centre for Complement and Inflammation Research, Department of Medicine, Imperial College Hammersmith Campus, London, UK
| | - Santiago Rodríguez de Córdoba
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain; Centro de Investigación Biomédica en Enfermedades Raras, Madrid, Spain
| | - Lubka T Roumenina
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche S1138, Complément et Maladies, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Université Pierre et Marie Curie (UPMC-Paris-6), Paris, France
| | - Sanjeev Sethi
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Richard J H Smith
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA; Division of Nephrology, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
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Abstract
C3 glomerulopathy (C3G) is a recently identified disease entity caused by dysregulation of the alternative complement pathway, and dense deposit disease (DDD) and C3 glomerulonephritis (C3GN) are its components. Because laboratory detection of complement dysregulation is still uncommon in practice, "dominant C3 deposition by two orders greater than that of immunoglobulins in the glomeruli by immunofluorescence", as stated in the consensus report, defines C3G. However, this morphological definition possibly includes the cases with glomerular diseases of different mechanisms such as post-infectious glomerulonephritis. In addition, the differential diagnosis between DDD and C3GN is often difficult because the distinction between these two diseases is based solely on electron microscopic features. Recent molecular and genetic advances provide information to characterize C3G. Some C3G cases are found with genetic abnormalities in complement regulatory factors, but majority of cases seem to be associated with acquired factors that dysregulate the alternative complement pathway. Because clinical courses and prognoses among glomerular diseases with dominant C3 deposition differ, further understanding the background mechanism, particularly complement dysregulation in C3G, is needed. This may resolve current dilemmas in practice and shed light on novel targeted therapies to remedy the dysregulated alternative complement pathway in C3G.
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Kakita H, Miyake T, Komiya T, Tsukamoto T, Muso E. A case report of recurrent C3 glomerulonephritis 18 months after renal transplantation. RENAL REPLACEMENT THERAPY 2016. [DOI: 10.1186/s41100-016-0049-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Familial C3 glomerulonephritis caused by a novel CFHR5-CFHR2 fusion gene. Mol Immunol 2016; 77:89-96. [PMID: 27490940 DOI: 10.1016/j.molimm.2016.07.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 07/10/2016] [Accepted: 07/12/2016] [Indexed: 11/23/2022]
Abstract
C3 glomerulopathy (C3G) is an ultra-rare complement-mediated renal disease characterized histologically by the predominance of C3 deposition within in the glomerulus. Familial cases of C3G are extremely uncommon and offer unique insight into the genetic drivers of complement dysregulation. In this report, we describe a patient who presented with C3G. Because a relative carried the same diagnosis, we sought an underlying genetic commonality to explain the phenotype. As part of a comprehension genetic screen, we completed multiplex ligation-dependent probe amplification across the complement factor H related region and identified amplification alterations consistent with a genomic rearrangement. Using comparative genomic hybridization, we narrowed and then cloned the rearrangement breakpoints thereby defining a novel fusion gene that is translated into a serum protein comprised of factor H related-5 (short consensus repeats 1 and 2) and factor H-related-2 (short consensus repeats 1-4). These data highlight the role of factor H related proteins in the control of complement activity and illustrate how perturbation of that control leads to C3G.
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Abstract
C3 glomerulopathy (C3G) describes a spectrum of glomerular diseases defined by shared renal biopsy pathology: a predominance of C3 deposition on immunofluorescence with electron microscopy permitting disease sub-classification. Complement dysregulation underlies the observed pathology, a causal relationship that is supported by well described studies of genetic and acquired drivers of disease. In this article, we provide an overview of the features of C3G, including a discussion of disease definition and a review of the causal role of complement. We discuss molecular markers of disease and how biomarkers are informing our evolving understanding of underlying pathology. Research advances are laying the foundation for complement inhibition as a targeted approach to treatment of C3G.
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Salvadori M, Rosso G. Reclassification of membranoproliferative glomerulonephritis: Identification of a new GN: C3GN. World J Nephrol 2016; 5:308-320. [PMID: 27458560 PMCID: PMC4936338 DOI: 10.5527/wjn.v5.i4.308] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 03/31/2016] [Accepted: 05/27/2016] [Indexed: 02/06/2023] Open
Abstract
This review revises the reclassification of the membranoproliferative glomerulonephritis (MPGN) after the consensus conference that by 2015 reclassified all the glomerulonephritis basing on etiology and pathogenesis, instead of the histomorphological aspects. After reclassification, two types of MPGN are to date recognized: The immunocomplexes mediated MPGN and the complement mediated MPGN. The latter type is more extensively described in the review either because several of these entities are completely new or because the improved knowledge of the complement cascade allowed for new diagnostic and therapeutic approaches. Overall the complement mediated MPGN are related to acquired or genetic cause. The presence of circulating auto antibodies is the principal acquired cause. Genetic wide association studies and family studies allowed to recognize genetic mutations of different types as causes of the complement dysregulation. The complement cascade is a complex phenomenon and activating factors and regulating factors should be distinguished. Genetic mutations causing abnormalities either in activating or in regulating factors have been described. The diagnosis of the complement mediated MPGN requires a complete study of all these different complement factors. As a consequence, new therapeutic approaches are becoming available. Indeed, in addition to a nonspecific treatment and to the immunosuppression that has the aim to block the auto antibodies production, the specific inhibition of complement activation is relatively new and may act either blocking the C5 convertase or the C3 convertase. The drugs acting on C3 convertase are still in different phases of clinical development and might represent drugs for the future. Overall the authors consider that one of the principal problems in finding new types of drugs are both the rarity of the disease and the consequent poor interest in the marketing and the lack of large international cooperative studies.
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Differences in clinical findings, pathology, and outcomes between C3 glomerulonephritis and membranoproliferative glomerulonephritis. Pediatr Nephrol 2016; 31:1091-9. [PMID: 26846787 DOI: 10.1007/s00467-015-3307-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/21/2015] [Accepted: 12/21/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND To clarify the clinical manifestations of pediatric complement component C3 glomerulonephritis (C3GN), we retrospectively evaluated differences in the clinicopathological findings and prognosis between C3GN and immune-complex-mediated membranoproliferative glomerulonephritis (IC-MPGN). METHODS Thirty-seven patients diagnosed with "idiopathic MPGN" were enrolled in this retrospective study. The patients were divided into two groups, with Group 1 consisting of 19 patients diagnosed with IC-MPGN and Group 2 consisting of 18 patients diagnosed with C3GN. The clinical findings and the prognosis were investigated for both groups. RESULTS Thirteen patients in Group 2 were identified by mandatory annual school screening for urinary abnormalities. The incidence of macro-hematuria and the frequency of low serum C4 values were lower in Group 2 patients than in Group 1 patients. At the time of the second renal biopsy, urinary protein excretion, incidence of hematuria, frequency of low serum C3 values, and scores for mesangial proliferation, glomerular sclerosis, and interstitial fibrosis were higher in Group 2 patients than in Group 1 patients. At the most recent follow-up examination, the number of patients categorized as non-responding or with end-stage renal disease was higher in Group 2 patients than in Group 1 patients. CONCLUSIONS Our results suggest that the treatment response and prognosis of patients with C3GN are worse than those of patients with IC-mediated MPGN. Therefore, in the clinical context regarding treatment options and prognosis, it may be useful to classify idiopathic MPGN as C3GN or IC-MPGN. In addition, long-term follow-up of C3GN is necessary.
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Distinct roles for the complement regulators factor H and Crry in protection of the kidney from injury. Kidney Int 2016; 90:109-22. [PMID: 27165610 DOI: 10.1016/j.kint.2016.02.036] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 02/23/2016] [Accepted: 02/25/2016] [Indexed: 12/29/2022]
Abstract
Mutations in the complement regulatory proteins are associated with several different diseases. Although these mutations cause dysregulated alternative pathway activation throughout the body, the kidneys are the most common site of injury. The susceptibility of the kidney to alternative pathway-mediated injury may be due to limited expression of complement regulatory proteins on several tissue surfaces within the kidney. To examine the roles of the complement regulatory proteins factor H and Crry in protecting distinct renal surfaces from alternative pathway mediated injury, we generated mice with targeted deletions of the genes for both proteins. Surprisingly, mice with combined genetic deletions of factor H and Crry developed significantly milder renal injury than mice deficient in only factor H. Deficiency of both factor H and Crry was associated with C3 deposition at multiple locations within the kidney, but glomerular C3 deposition was lower than that in factor H alone deficient mice. Thus, factor H and Crry are critical for regulating complement activation at distinct anatomic sites within the kidney. However, widespread activation of the alternative pathway reduces injury by depleting the pool of C3 available at any 1 location.
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41
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Vernon KA, Ruseva MM, Cook HT, Botto M, Malik TH, Pickering MC. Partial Complement Factor H Deficiency Associates with C3 Glomerulopathy and Thrombotic Microangiopathy. J Am Soc Nephrol 2016; 27:1334-42. [PMID: 26374608 PMCID: PMC4849824 DOI: 10.1681/asn.2015030295] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 07/28/2015] [Indexed: 11/03/2022] Open
Abstract
The complement-mediated renal diseases C3 glomerulopathy (C3G) and atypical hemolytic uremic syndrome (aHUS) strongly associate with inherited and acquired abnormalities in the regulation of the complement alternative pathway (AP). The major negative regulator of the AP is the plasma protein complement factor H (FH). Abnormalities in FH result in uncontrolled activation of C3 through the AP and associate with susceptibility to both C3G and aHUS. Although previously developed FH-deficient animal models have provided important insights into the mechanisms underlying susceptibility to these unique phenotypes, these models do not entirely reproduce the clinical observations. FH is predominantly synthesized in the liver. We generated mice with hepatocyte-specific FH deficiency and showed that these animals have reduced plasma FH levels with secondary reduction in plasma C3. Unlike mice with complete FH deficiency, hepatocyte-specific FH-deficient animals developed neither plasma C5 depletion nor accumulation of C3 along the glomerular basement membrane. In contrast, subtotal FH deficiency associated with mesangial C3 accumulation consistent with C3G. Although there was no evidence of spontaneous thrombotic microangiopathy, the hepatocyte-specific FH-deficient animals developed severe C5-dependent thrombotic microangiopathy after induction of complement activation within the kidney by accelerated serum nephrotoxic nephritis. Taken together, our data indicate that subtotal FH deficiency can give rise to either spontaneous C3G or aHUS after a complement-activating trigger within the kidney and that the latter is C5 dependent.
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Affiliation(s)
- Katherine A Vernon
- Centre for Complement and Inflammation Research, Imperial College, London, United Kingdom
| | - Marieta M Ruseva
- Centre for Complement and Inflammation Research, Imperial College, London, United Kingdom
| | - H Terence Cook
- Centre for Complement and Inflammation Research, Imperial College, London, United Kingdom
| | - Marina Botto
- Centre for Complement and Inflammation Research, Imperial College, London, United Kingdom
| | - Talat H Malik
- Centre for Complement and Inflammation Research, Imperial College, London, United Kingdom
| | - Matthew C Pickering
- Centre for Complement and Inflammation Research, Imperial College, London, United Kingdom
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Moreno JA, Yuste C, Gutiérrez E, Sevillano ÁM, Rubio-Navarro A, Amaro-Villalobos JM, Praga M, Egido J. Haematuria as a risk factor for chronic kidney disease progression in glomerular diseases: A review. Pediatr Nephrol 2016; 31:523-33. [PMID: 25980470 DOI: 10.1007/s00467-015-3119-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 04/15/2015] [Accepted: 04/20/2015] [Indexed: 12/18/2022]
Abstract
Haematuria has long been considered to be a benign condition associated with glomerular diseases. However, new evidences suggest that haematuria has a pathogenic role in promoting kidney disease progression. An increased risk for end-stage renal disease has been reported in adolescents and young adults with persistent microscopic haematuria. A persistent impairment of renal function has been also reported following macroscopic haematuria-associated acute kidney injury in immunoglobulin A nephropathy. Haematuria-induced renal damage has been related to oxidant, cytotoxic and inflammatory effects induced by haemoglobin or haem released from red blood cells. The pathophysiological origin of haematuria may be due to a more fragile and easily ruptured glomerular filtration barrier, as reported in several glomerular diseases. In this review we describe a number of the key issues associated with the epidemiology and pathogenesis of haematuria-associated diseases, provide an update of recent knowledge on the role of haematuria on renal function outcome and discuss specific therapeutic approaches in this setting. KEY SUMMARY POINTS: 1. Glomerular haematuria is a common observation in a number of renal diseases that may lead to persistent renal injury. 2. Haematuria in children differs from that in adults in specific aspects, particularly in the frequency of glomerular diseases and renal disease outcome. 3. Regular follow-up of renal function in children with isolated microhaematuria may be recommended.
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Affiliation(s)
- Juan Antonio Moreno
- Renal, Vascular and Diabetes Research Laboratory, IIS-Fundación Jiménez Díaz, Autonoma University, Av. Reyes Católicos 2, 28040, Madrid, Spain.
| | - Claudia Yuste
- Department of Nephrology, Gregorio Marañon Hospital, 28007, Madrid, Spain
| | - Eduardo Gutiérrez
- Department of Nephrology, 12 de Octubre Hospital, 28041, Madrid, Spain
| | - Ángel M Sevillano
- Department of Nephrology, 12 de Octubre Hospital, 28041, Madrid, Spain
| | - Alfonso Rubio-Navarro
- Renal, Vascular and Diabetes Research Laboratory, IIS-Fundación Jiménez Díaz, Autonoma University, Av. Reyes Católicos 2, 28040, Madrid, Spain
| | - Juan Manuel Amaro-Villalobos
- Renal, Vascular and Diabetes Research Laboratory, IIS-Fundación Jiménez Díaz, Autonoma University, Av. Reyes Católicos 2, 28040, Madrid, Spain
| | - Manuel Praga
- Department of Nephrology, 12 de Octubre Hospital, 28041, Madrid, Spain
| | - Jesús Egido
- Renal, Vascular and Diabetes Research Laboratory, IIS-Fundación Jiménez Díaz, Autonoma University, Av. Reyes Católicos 2, 28040, Madrid, Spain.,Spanish Biomedical Research Network in Diabetes and Associated Metabolic Disorders (CIBERDEM), Madrid, Spain
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43
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Muff-Luett M, Nester CM. The Genetics of Ultra-Rare Renal Disease. J Pediatr Genet 2016; 5:33-42. [PMID: 27617140 DOI: 10.1055/s-0036-1572515] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 12/02/2015] [Indexed: 12/14/2022]
Abstract
The complement-mediated renal diseases are a group of ultra-rare renal diseases that disproportionately affect children and young adults and frequently lead to irreversible renal failure. Genetic mutations in alternate pathway of complement genes are pathomechanistically involved in a significant number of these unique diseases. Here, we review our current understanding of the role of genetics in the primary complement-mediated renal diseases affecting children, with a focus on atypical hemolytic uremic syndrome and C3 glomerulopathy. Also, included is a brief discussion of the related diseases whose relationship to complement abnormality has been suspected but not yet confirmed. Advances in genetics have transformed both treatment and outcomes in these historically difficult to treat, highly morbid diseases.
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Affiliation(s)
- Melissa Muff-Luett
- Division of Pediatric Nephrology, University of Nebraska Medical Center, Omaha, Nebraska, United States
| | - Carla M Nester
- Division of Pediatric Nephrology, Dialysis and Transplantation, Stead Family Department of Pediatrics, University of Iowa, Iowa City, Iowa, United States; Molecular Otolaryngology and Renal Research Laboratory, University of Iowa, Iowa City, Iowa, United States
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44
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Yuste C, Rivera F, Moreno JA, López-Gómez JM. Haematuria on the Spanish Registry of Glomerulonephritis. Sci Rep 2016; 6:19732. [PMID: 26818712 PMCID: PMC4730139 DOI: 10.1038/srep19732] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 12/15/2015] [Indexed: 12/24/2022] Open
Abstract
Recent studies suggest a pathogenic role for glomerular haematuria among renal function. However, there is no data on the prevalence of haematuria from a large renal biopsy registry. We analysed the prevalence of gross (GH) and microscopic (mH) haematuria in 19,895 patients that underwent native renal biopsies from the Spanish Registry of Glomerulonephritis. Haematuria's overall incidence was 63% (GH 8.6% and mH 55.1%), being more frequent in males (64.7% vs. 62.4%). GH was more prevalent in patients <18 years (21.3% vs. 7.7%). The commonest clinical presentation associated with GH was acute kidney injury (31.5%) and IgA Nephropathy (IgAN) (33.6%) was the most frequent histological finding. GH patients showed a significantly (p < 0.05) lower eGFR and proteinuria levels as compared with patients with mH and without haematuria. Moreover, mH was more prevalent in adults (56.3%). Nephrotic syndrome was the commonest clinical presentation in mH patients (32.2%) and IgAN (18.5%) the most frequent histological finding. In conclusion, haematuria, is a frequent urinalysis finding in patients underwent native renal biopsy. The most frequent histological finding in both GH and mH is IgAN. Whereas, GH is more frequent in young males with acute kidney injury, mH is commoner among adults with nephrotic syndrome.
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Affiliation(s)
| | | | - Juan Antonio Moreno
- Renal,Vascular and Diabetes Research Lab. IIS-Fundación Jiménez Díaz. Autonóma University, Madrid, Spain
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45
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Vivante A, Hildebrandt F. Exploring the genetic basis of early-onset chronic kidney disease. Nat Rev Nephrol 2016; 12:133-46. [PMID: 26750453 DOI: 10.1038/nrneph.2015.205] [Citation(s) in RCA: 215] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The primary causes of chronic kidney disease (CKD) in children differ from those of CKD in adults. In the USA the most common diagnostic groups of renal disease that manifest before the age of 25 years are congenital anomalies of the kidneys and urinary tract, steroid-resistant nephrotic syndrome, chronic glomerulonephritis and renal cystic ciliopathies, which together encompass >70% of early-onset CKD diagnoses. Findings from the past decade suggest that early-onset CKD is caused by mutations in any one of over 200 different monogenic genes. Developments in high-throughput sequencing in the past few years has rendered identification of causative mutations in this high number of genes feasible. Use of genetic analyses in patients with early onset-CKD will provide patients and their families with a molecular genetic diagnosis, generate new insights into disease mechanisms, facilitate aetiology-based classifications of patient cohorts for clinical studies, and might have consequences for personalized approaches to the prevention and treatment of CKD. In this Review, we discuss the implications of next-generation sequencing in clinical genetic diagnostics and the discovery of novel genes in early-onset CKD. We also delineate the resulting opportunities for deciphering disease mechanisms and the therapeutic implications of these findings.
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Affiliation(s)
- Asaf Vivante
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, Massachusetts 02115, USA.,Talpiot Medical Leadership Program, Sheba Medical Center, Tel-Hashomer 52621, Israel
| | - Friedhelm Hildebrandt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, Massachusetts 02115, USA
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46
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Chan MM, Gale DP. Isolated microscopic haematuria of glomerular origin: clinical significance and diagnosis in the 21st century. Clin Med (Lond) 2015; 15:576-80. [PMID: 26621952 PMCID: PMC4953265 DOI: 10.7861/clinmedicine.15-6-576] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Isolated microscopic, or non-visible, haematuria of glomerular origin was previously regarded a benign finding, but it is now known that, even in the absence of proteinuria, hypertension or renal impairment at presentation, haematuria is associated with increased risk of kidney failure in the long term. The most common causes of isolated microscopic haematuria among children and young adults are IgA nephropathy, Alport syndrome (AS), and thin basement membrane nephropathy (TBMN). AS, which is usually inherited as an X-linked or autosomal recessive trait, and TBMN, which is usually autosomal dominant, are caused by mutations in the genes encoding type-IV collagen, an abundant component of the glomerular basement membrane. A detailed family history with screening of at-risk relatives is important, allowing prompt diagnosis of affected relatives and helping determine the mode of transmission. As costs fall and availability increases, genetic testing is increasingly being used in clinical practice to provide diagnostic and predictive information for patients and their families.
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Affiliation(s)
- Melanie My Chan
- Centre for Nephrology, University College London, Royal Free Hospital, London, UK
| | - Daniel P Gale
- Centre for Nephrology, University College London, Royal Free Hospital, London, UK
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47
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Chen Q, Manzke M, Hartmann A, Büttner M, Amann K, Pauly D, Wiesener M, Skerka C, Zipfel PF. Complement Factor H-Related 5-Hybrid Proteins Anchor Properdin and Activate Complement at Self-Surfaces. J Am Soc Nephrol 2015; 27:1413-25. [PMID: 26432903 DOI: 10.1681/asn.2015020212] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 08/04/2015] [Indexed: 12/12/2022] Open
Abstract
C3 glomerulopathy (C3G) is a severe kidney disease for which no specific therapy exists. The causes of C3G are heterogeneous, and defective complement regulation is often linked to C3G pathogenesis. Copy number variations in the complement factor H-related (CFHR) gene cluster on chromosome 1q32 and CFHR5 mutant proteins associate with this disease. Here, we identified CFHR5 as a pattern recognition protein that binds to damaged human endothelial cell surfaces and to properdin, the human complement activator. We found the two N-terminal short consensus repeat domains of CFHR5 contact properdin and mediate dimer formation. These properdin-binding segments are duplicated in two mutant CFHR5 proteins, CFHR2-CFHR5Hyb from German patients with C3G and CFHR5Dup from Cypriot patients with C3G. Each of these mutated proteins assembled into large multimeric complexes and, compared to CFHR5, bound damaged human cell surfaces and properdin with greater intensity and exacerbated local complement activation. This enhanced surface binding and properdin recruitment was further evidenced in the mesangia of a transplanted and explanted kidney from a German patient with a CFHR2-CFHR5Hyb protein. Enhanced properdin staining correlated with local complement activation with C3b and C5b-9 deposition on the mesangial cell surface in vitro This gain of function in complement activation for two disease-associated CFHR5 mutants describes a new disease mechanism of C3G, which is relevant for defining appropriate treatment options for this disorder.
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Affiliation(s)
- Qian Chen
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Melanie Manzke
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Andrea Hartmann
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Maike Büttner
- Department of Nephrology and Hypertension, Friedrich-Alexander University of Erlangen-Nuremberg, Germany
| | - Kerstin Amann
- Department of Nephrology and Hypertension, Friedrich-Alexander University of Erlangen-Nuremberg, Germany
| | - Diana Pauly
- University Hospital Regensburg, Regensburg, Germany; and
| | - Michael Wiesener
- Department of Nephrology and Hypertension, Friedrich-Alexander University of Erlangen-Nuremberg, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany; Friedrich Schiller University, Jena, Germany
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Abstract
C3 glomerulonephritis is a clinicopathologic entity defined by the presence of isolated or dominant deposits of C3 on immunofluorescence. To explore the effect of immunosuppression on C3 glomerulonephritis, we studied a series of 60 patients in whom a complete registry of treatments was available over a median follow-up of 47 months. Twenty patients had not received immunosuppressive treatments. In the remaining 40 patients, 22 had been treated with corticosteroids plus mycophenolate mofetil while 18 were treated with other immunosuppressive regimens (corticosteroids alone or corticosteroids plus cyclophosphamide). The number of patients developing end-stage renal disease was significantly lower among treated compared with untreated patients (3 vs. 7 patients, respectively). No patient in the corticosteroids plus mycophenolate mofetil group doubled serum creatinine nor developed end-stage renal disease, as compared with 7 (significant) and 3 (not significant), respectively, in patients treated with other immunosuppressive regimens. Renal survival (100, 80, and 72% at 5 years) and the number of patients achieving clinical remission (86, 50, and 25%) were significantly higher in patients treated with corticosteroids plus mycophenolate mofetil as compared with patients treated with other immunosuppressive regimens and untreated patients, respectively. Thus, immunosuppressive treatments, particularly corticosteroids plus mycophenolate mofetil, can be beneficial in C3 glomerulonephritis.
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49
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De Vriese AS, Sethi S, Van Praet J, Nath KA, Fervenza FC. Kidney Disease Caused by Dysregulation of the Complement Alternative Pathway: An Etiologic Approach. J Am Soc Nephrol 2015; 26:2917-29. [PMID: 26185203 DOI: 10.1681/asn.2015020184] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Kidney diseases caused by genetic or acquired dysregulation of the complement alternative pathway (AP) are traditionally classified on the basis of clinical presentation (atypical hemolytic uremic syndrome as thrombotic microangiopathy), biopsy appearance (dense deposit disease and C3 GN), or clinical course (atypical postinfectious GN). Each is characterized by an inappropriate activation of the AP, eventuating in renal damage. The clinical diversity of these disorders highlights important differences in the triggers, the sites and intensity of involvement, and the outcome of the AP dysregulation. Nevertheless, we contend that these diseases should be grouped as disorders of the AP and classified on an etiologic basis. In this review, we define different pathophysiologic categories of AP dysfunction. The precise identification of the underlying abnormality is the key to predict the response to immune suppression, plasma infusion, and complement-inhibitory drugs and the outcome after transplantation. In a patient with presumed dysregulation of the AP, the collaboration of the clinician, the renal pathologist, and the biochemical and genetic laboratory is very much encouraged, because this enables the elucidation of both the underlying pathogenesis and the optimal therapeutic approach.
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Affiliation(s)
- An S De Vriese
- Division of Nephrology, AZ Sint-Jan Brugge-Oostende AV, Brugge, Belgium; and
| | | | - Jens Van Praet
- Division of Nephrology, AZ Sint-Jan Brugge-Oostende AV, Brugge, Belgium; and
| | - Karl A Nath
- Nephrology and Hypertension, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Fernando C Fervenza
- Nephrology and Hypertension, Mayo Clinic College of Medicine, Rochester, Minnesota
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Ruseva MM, Peng T, Lasaro MA, Bouchard K, Liu-Chen S, Sun F, Yu ZX, Marozsan A, Wang Y, Pickering MC. Efficacy of Targeted Complement Inhibition in Experimental C3 Glomerulopathy. J Am Soc Nephrol 2015; 27:405-16. [PMID: 26047789 DOI: 10.1681/asn.2014121195] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/01/2015] [Indexed: 12/19/2022] Open
Abstract
C3 glomerulopathy refers to renal disorders characterized by abnormal accumulation of C3 within the kidney, commonly along the glomerular basement membrane (GBM). C3 glomerulopathy is associated with complement alternative pathway dysregulation, which includes functional defects in complement regulator factor H (FH). There is no effective treatment for C3 glomerulopathy. We investigated the efficacy of a recombinant mouse protein composed of domains from complement receptor 2 (CR2) and FH (CR2-FH) in two models of C3 glomerulopathy with either preexisting or triggered C3 deposition along the GBM. FH-deficient mice spontaneously develop renal pathology associated with abnormal C3 accumulation along the GBM and secondary plasma C3 deficiency. CR2-FH partially restored plasma C3 levels in FH-deficient mice 2 hours after intravenous injection. CR2-FH specifically targeted glomerular C3 deposits, reduced the linear C3 reactivity assessed with anti-C3 and anti-C3b/iC3b/C3c antibodies, and prevented further spontaneous accumulation of C3 fragments along the GBM. Reduction in glomerular C3d and C9/C5b-9 reactivity was observed after daily administration of CR2-FH for 1 week. In a second mouse model with combined deficiency of FH and complement factor I, CR2-FH prevented de novo C3 deposition along the GBM. These data show that CR2-FH protects the GBM from both spontaneous and triggered C3 deposition in vivo and indicate that this approach should be tested in C3 glomerulopathy.
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Affiliation(s)
- Marieta M Ruseva
- Centre for Complement and Inflammation Research, Imperial College, London, United Kingdom; and
| | - Tao Peng
- Alexion Pharmaceuticals, Cheshire, Connecticut
| | | | | | | | - Fang Sun
- Alexion Pharmaceuticals, Cheshire, Connecticut
| | - Zhao-Xue Yu
- Alexion Pharmaceuticals, Cheshire, Connecticut
| | | | - Yi Wang
- Alexion Pharmaceuticals, Cheshire, Connecticut
| | - Matthew C Pickering
- Centre for Complement and Inflammation Research, Imperial College, London, United Kingdom; and
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