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1. FHR-5 Serum Levels and CFHR5 Genetic Variations in Patients With Immune Complex-Mediated Membranoproliferative Glomerulonephritis and C3-Glomerulopathy

Author

Nóra Garam, Marcell Cserhalmi, Zoltán Prohászka, Ágnes Szilágyi, Nóra Veszeli, Edina Szabó, Barbara Uzonyi, Attila Iliás, Christof Aigner, Alice Schmidt, Martina Gaggl, Gere Sunder-Plassmann, Dóra Bajcsi, Jürgen Brunner, Alexandra Dumfarth, Daniel Cejka, Stefan Flaschberger, Hana Flögelova, Ágnes Haris, Ágnes Hartmann, Andreas Heilos, Thomas Mueller, Krisztina Rusai, Klaus Arbeiter, Johannes Hofer, Dániel Jakab, Mária Sinkó, Erika Szigeti, Csaba Bereczki, Viktor Janko, Kata Kelen, György S. Reusz, Attila J. Szabó, Nóra Klenk, Krisztina Kóbor, Nika Kojc, Maarten Knechtelsdorfer, Mario Laganovic, Adrian Catalin Lungu, Anamarija Meglic, Rina Rus, Tanja Kersnik Levart, Ernesta Macioniene, Marius Miglinas, Anna Pawłowska, Tomasz Stompór, Ludmila Podracka, Michael Rudnicki, Gert Mayer, Romana Rysava, Jana Reiterova, Marijan Saraga, Tomáš Seeman, Jakub Zieg, Eva Sládková, Natasa Stajic, Tamás Szabó, Andrei Capitanescu, Simona Stancu, Miroslav Tisljar, Kresimir Galesic, András Tislér, Inga Vainumäe, Martin Windpessl, Tomas Zaoral, Galia Zlatanova, Mihály Józsi, and Dorottya Csuka

Subjects
membranoproliferative glomerulonephritis, immune complex-mediated glomerulonephritis, C3 glomerulopathy, dense deposit disease (DDD), C3 glomerulonephritis (C3GN), Immunologic diseases. Allergy, RC581-607
Abstract

BackgroundFactor H-related protein 5 (FHR-5) is a member of the complement Factor H protein family. Due to the homology to Factor H, the main complement regulator of the alternative pathway, it may also be implicated in the pathomechanism of kidney diseases where Factor H and alternative pathway dysregulation play a role. Here, we report the first observational study on CFHR5 variations along with serum FHR-5 levels in immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) and C3 glomerulopathy (C3G) patients together with the clinical, genetic, complement, and follow-up data.MethodsA total of 120 patients with a histologically proven diagnosis of IC-MPGN/C3G were enrolled in the study. FHR-5 serum levels were measured in ELISA, the CFHR5 gene was analyzed by Sanger sequencing, and selected variants were studied as recombinant proteins in ELISA and surface plasmon resonance (SPR).ResultsEight exonic CFHR5 variations in 14 patients (12.6%) were observed. Serum FHR-5 levels were lower in patients compared to controls. Low serum FHR-5 concentration at presentation associated with better renal survival during the follow-up period; furthermore, it showed clear association with signs of complement overactivation and clinically meaningful clusters.ConclusionsOur observations raise the possibility that the FHR-5 protein plays a fine-tuning role in the pathogenesis of IC-MPGN/C3G.

Published
2021
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2. C4 nephritic factor in patients with immune-complex-mediated membranoproliferative glomerulonephritis and C3-glomerulopathy

Author

Nóra Garam, Zoltán Prohászka, Ágnes Szilágyi, Christof Aigner, Alice Schmidt, Martina Gaggl, Gere Sunder-Plassmann, Dóra Bajcsi, Jürgen Brunner, Alexandra Dumfarth, Daniel Cejka, Stefan Flaschberger, Hana Flögelova, Ágnes Haris, Ágnes Hartmann, Andreas Heilos, Thomas Mueller, Krisztina Rusai, Klaus Arbeiter, Johannes Hofer, Dániel Jakab, Mária Sinkó, Erika Szigeti, Csaba Bereczki, Viktor Janko, Kata Kelen, György S. Reusz, Attila J. Szabó, Nóra Klenk, Krisztina Kóbor, Nika Kojc, Maarten Knechtelsdorfer, Mario Laganovic, Adrian Catalin Lungu, Anamarija Meglic, Rina Rus, Tanja Kersnik-Levart, Ernesta Macioniene, Marius Miglinas, Anna Pawłowska, Tomasz Stompór, Ludmila Podracka, Michael Rudnicki, Gert Mayer, Romana Rysava, Jana Reiterova, Marijan Saraga, Tomáš Seeman, Jakub Zieg, Eva Sládková, Tamás Szabó, Andrei Capitanescu, Simona Stancu, Miroslav Tisljar, Kresimir Galesic, András Tislér, Inga Vainumäe, Martin Windpessl, Tomas Zaoral, Galia Zlatanova, and Dorottya Csuka

Subjects
C4 nephritic factor, C3 glomerulopathy, Membranoproliferative glomerulonephritis, C3 nephritic factor, Dense deposit disease, C3 glomerulonephritis, Medicine
Abstract

Abstract Background Acquired or genetic abnormalities of the complement alternative pathway are the primary cause of C3glomerulopathy(C3G) but may occur in immune-complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) as well. Less is known about the presence and role of C4nephritic factor(C4NeF) which may stabilize the classical pathway C3-convertase. Our aim was to examine the presence of C4NeF and its connection with clinical features and with other pathogenic factors. Results One hunfe IC-MPGN/C3G patients were enrolled in the study. C4NeF activity was determined by hemolytic assay utilizing sensitized sheep erythrocytes. Seventeen patients were positive for C4NeF with lower prevalence of renal impairment and lower C4d level, and higher C3 nephritic factor (C3NeF) prevalence at time of diagnosis compared to C4NeF negative patients. Patients positive for both C3NeF and C4NeF had the lowest C3 levels and highest terminal pathway activation. End-stage renal disease did not develop in any of the C4NeF positive patients during follow-up period. Positivity to other complement autoantibodies (anti-C1q, anti-C3) was also linked to the presence of nephritic factors. Unsupervised, data-driven cluster analysis identified a group of patients with high prevalence of multiple complement autoantibodies, including C4NeF. Conclusions In conclusion, C4NeF may be a possible cause of complement dysregulation in approximately 10–15% of IC-MPGN/C3G patients.

Published
2019
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3. Validation of distinct pathogenic patterns in a cohort of membranoproliferative glomerulonephritis patients by cluster analysis

Author

Dániel Jakab, Ágnes Szilágyi, Gert Mayer, Nóra Garam, Miroslav Tisljar, Viktor Janko, Attila Szabo, Inga Vainumäe, Christof Aigner, Ágnes Hartmann, Simona Stancu, Galia Zlatanova, Tamás Szabó, Marius Miglinas, András Tislér, Krisztina Kóbor, Tomáš Seeman, Mária Sinkó, Alice Schmidt, Stefan Flaschberger, Hana Flögelová, Nika Kojc, Klaus Arbeiter, Jana Reiterova, Tomas Zaoral, Michael A. Rudnicki, Gere Sunder-Plassmann, Romana Rysava, Jürgen Brunner, Maarten Knechtelsdorfer, Daniel Cejka, Ágnes Haris, György Reusz, Krešimir Galešić, Mario Laganović, Tomasz Stompór, Anna Pawłowska, Anamarija Meglic, Eva Sládková, Dorottya Csuka, Andrei Capitanescu, Tanja Kersnik-Levart, Zoltán Prohászka, Rina Rus, Adrian Catalin Lungu, Csaba Bereczki, Marijan Saraga, Thomas Mueller, Ernesta Macioniene, Andreas Heilos, Krisztina Rusai, Kata Kelen, Erika Szigeti, Alexandra Dumfarth, Dóra Bajcsi, Ludmila Podracka, Martina Gaggl, Jakub Zieg, Nóra Klenk, Johannes Hofer, and Martin Windpessl

Subjects
C3 Glomerulonephritis, 030232 urology & nephrology, Late onset, C3-glomerulopathy, C3-glomerulonephritis, 03 medical and health sciences, Nephritic syndrome, 0302 clinical medicine, Membranoproliferative glomerulonephritis, medicine, complement, 030304 developmental biology, 0303 health sciences, Transplantation, dense deposit disease, membranoproliferative glomerulonephritis, business.industry, Incidence (epidemiology), Original Articles, medicine.disease, Nephrology, Immunology, Cohort, Age of onset, Complement membrane attack complex, business
Abstract

Background A novel data-driven cluster analysis identified distinct pathogenic patterns in C3-glomerulopathies and immune complex-mediated membranoproliferative glomerulonephritis. Our aim was to replicate these observations in an independent cohort and elucidate disease pathophysiology with detailed analysis of functional complement markers. Methods A total of 92 patients with clinical, histological, complement and genetic data were involved in the study, and hierarchical cluster analysis was done by Ward method, where four clusters were generated. Results High levels of sC5b-9 (soluble membrane attack complex), low serum C3 levels and young age at onset (13 years) were characteristic for Cluster 1 with a high prevalence of likely pathogenic variations (LPVs) and C3 nephritic factor, whereas for Cluster 2—which is not reliable because of the small number of cases—strong immunoglobulin G staining, low C3 levels and high prevalence of nephritic syndrome at disease onset were observed. Low plasma sC5b-9 levels, decreased C3 levels and high prevalence of LPV and sclerotic glomeruli were present in Cluster 3, and patients with late onset of the disease (median: 39.5 years) and near-normal C3 levels in Cluster 4. A significant difference was observed in the incidence of end-stage renal disease during follow-up between the different clusters. Patients in Clusters 3–4 had worse renal survival than patients in Clusters 1–2. Conclusions Our results confirm the main findings of the original cluster analysis and indicate that the observed, distinct pathogenic patterns are replicated in our cohort. Further investigations are necessary to analyse the distinct biological and pathogenic processes in these patient groups.

Published
2019

4. C4 nephritic factor in patients with immune-complex-mediated membranoproliferative glomerulonephritis and C3-glomerulopathy

Author

Ágnes Szilágyi, Christof Aigner, Attila Szabo, Tanja Kersnik-Levart, Dorottya Csuka, Ágnes Haris, Alice Schmidt, Rina Rus, Stefan Flaschberger, Ernesta Macioniene, Hana Flögelová, Anamarija Meglic, Ludmila Podracka, Gere Sunder-Plassmann, Alexandra Dumfarth, Martina Gaggl, Andrei Capitanescu, Viktor Janko, Anna Pawłowska, Gert Mayer, Thomas Mueller, Ágnes Hartmann, András Tislér, Kata Kelen, Erika Szigeti, Galia Zlatanova, Martin Windpessl, Tamás Szabó, Klaus Arbeiter, Mario Laganović, György Reusz, Romana Rysava, Krisztina Kóbor, Jakub Zieg, Daniel Cejka, Michael A. Rudnicki, Andreas Heilos, Krisztina Rusai, Dániel Jakab, Tomas Zaoral, Nóra Klenk, Johannes Hofer, Nóra Garam, Krešimir Galešić, Jürgen Brunner, Miroslav Tisljar, Marius Miglinas, Mária Sinkó, Csaba Bereczki, Inga Vainumäe, Nika Kojc, Marijan Saraga, Tomáš Seeman, Simona Stancu, Eva Sládková, Jana Reiterova, Zoltán Prohászka, Maarten Knechtelsdorfer, Adrian Catalin Lungu, Tomasz Stompór, and Dóra Bajcsi

Subjects
0301 basic medicine, Adult, Male, Adolescent, C3 Glomerulonephritis, Glomerulonephritis, Membranoproliferative, 030232 urology & nephrology, lcsh:Medicine, Disease, C4 nephritic factor, 03 medical and health sciences, Classical complement pathway, Young Adult, 0302 clinical medicine, C3 glomerulonephritis, Glomerulopathy, Membranoproliferative glomerulonephritis, Medicine, Humans, Pharmacology (medical), C3 glomerulopathy, C3 nephritic factor, Genetics (clinical), Autoantibodies, Complement C3 Nephritic Factor, Dense deposit disease, business.industry, Research, lcsh:R, Autoantibody, General Medicine, Complement System Proteins, medicine.disease, Immune complex, 030104 developmental biology, Immunology, Alternative complement pathway, Female, Kidney Diseases, business
Abstract

Background Acquired or genetic abnormalities of the complement alternative pathway are the primary cause of C3glomerulopathy(C3G) but may occur in immune-complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) as well. Less is known about the presence and role of C4nephritic factor(C4NeF) which may stabilize the classical pathway C3-convertase. Our aim was to examine the presence of C4NeF and its connection with clinical features and with other pathogenic factors. Results One hunfe IC-MPGN/C3G patients were enrolled in the study. C4NeF activity was determined by hemolytic assay utilizing sensitized sheep erythrocytes. Seventeen patients were positive for C4NeF with lower prevalence of renal impairment and lower C4d level, and higher C3 nephritic factor (C3NeF) prevalence at time of diagnosis compared to C4NeF negative patients. Patients positive for both C3NeF and C4NeF had the lowest C3 levels and highest terminal pathway activation. End-stage renal disease did not develop in any of the C4NeF positive patients during follow-up period. Positivity to other complement autoantibodies (anti-C1q, anti-C3) was also linked to the presence of nephritic factors. Unsupervised, data-driven cluster analysis identified a group of patients with high prevalence of multiple complement autoantibodies, including C4NeF. Conclusions In conclusion, C4NeF may be a possible cause of complement dysregulation in approximately 10–15% of IC-MPGN/C3G patients.

Published
2019

5. Elevated Uric Acid Increases the Risk for Kidney Disease

Author

Renate Klauser-Braun, Maarten Knechtelsdorfer, Rainer Oberbauer, Christian Temml, Rudolf P. Obermayr, and Georg Gutjahr

Subjects
Adult, Blood Glucose, Male, Risk, Nephrology, medicine.medical_specialty, Renal function, Blood Pressure, Nephropathy, chemistry.chemical_compound, Risk Factors, Internal medicine, medicine, Humans, Clinical Epidemiology, Risk factor, Antihypertensive Agents, business.industry, Cholesterol, HDL, General Medicine, Odds ratio, Middle Aged, medicine.disease, Uric Acid, Endocrinology, chemistry, Uric acid, Female, Kidney Diseases, Waist Circumference, Metabolic syndrome, business, Glomerular Filtration Rate, Kidney disease
Abstract

Recent epidemiologic studies suggest that uric acid predicts the development of new-onset kidney disease, but it is unclear whether uric acid is an independent risk factor. In this study, data from 21,475 healthy volunteers who were followed prospectively for a median of 7 yr were analyzed to examine the association between uric acid level and incident kidney disease (estimated GFR [eGFR]60 ml/min per 1.73 m(2)). After adjustment for baseline eGFR, a slightly elevated uric acid level (7.0 to 8.9 mg/dl) was associated with a nearly doubled risk for incident kidney disease (odds ratio 1.74; 95% confidence interval 1.45 to 2.09), and an elevated uric acid (or =9.0 mg/dl) was associated with a tripled risk (odds ratio 3.12; 95% confidence interval 2.29 to 4.25). These increases in risk remained significant even after adjustment for baseline eGFR, gender, age, antihypertensive drugs, and components of the metabolic syndrome (waist circumference, HDL cholesterol, blood glucose, triglycerides, and BP). In a fully adjusted spline model, the risk for incident kidney disease increased roughly linearly with uric acid level to a level of approximately 6 to 7 mg/dl in women and 7 to 8 mg/dl in men; above these levels, the associated risk increased rapidly. In conclusion, elevated levels of uric acid independently increase the risk for new-onset kidney disease.

Published
2008

6. Predictors of new-onset decline in kidney function in a general middle-european population.

Author

Rudolf P. Obermayr, Christian Temml, Maarten Knechtelsdorfer, Georg Gutjahr, Josef Kletzmayr, Susanne Heiss, Anton Ponholzer, Stephan Madersbacher, Rainer Oberbauer, and Renate Klauser-Braun

Subjects
KIDNEY diseases, PROTEINURIA, URINALYSIS, HYPERTENSION
Abstract

Background. Limited epidemiological data are available on predictors of new-onset kidney disease. Methods. In this longitudinal cohort study, 17 375 apparently healthy volunteers of the general Viennese population (46.4% women, age range 20–84 years, men 20–89 years) performed a baseline examination at some time within the study period (1990–2005) and completed a median of two follow-up examinations [interquartile range (IQR) 1 to 4]; the median follow-up period was 7 years (IQR 4 to 11). The outcome of interest was the development of kidney disease, defined as a decrease of the glomerular filtration rate (GFR) Results. The following parameters [odds ratios (OR) with 95% confidence intervals] predicted new-onset kidney disease: Age (increase by 5 years), OR = 1.36 (1.34–1.40); National Kidney Foundation-chronic kidney disease (NKF-CKD) stage 1 with proteinuria (), OR = 1.39 (1.10–1.75); NKF-CKD stage 1 with proteinuria (≥), OR = 2.07 (1.11–3.87); NKF-CKD stage 2 with proteinuria (), OR = 2.71 (2.10–3.51); NKF-CKD stage 2 with proteinuria (≥), OR = 3.80 (2.29–6.31); body mass index, OR = 1.04 (1.02–1.06); current-smoker, OR = 1.20 (1.01–1.43); performing no sports, OR = 1.57 (1.27–1.95); uric acid (increase by 2 mg/dl), OR = 1.69 (1.59–1.80); HDL-cholesterol (decrease by 10 mg/dl), OR = 1.12 (1.07–1.17); hypertension stage 1, OR = 1.35 (1.08–1.67); hypertension stage 2, OR = 2.01 (1.62–2.51); diabetes mellitus, OR = 1.44 (1.07–1.93). Conclusions. Cardiovascular risk factors as well as NKF-CKD stages 1 and 2 and proteinuria, the more the higher and an entirely novel finding, performing no sports, predicted new-onset kidney disease. [ABSTRACT FROM AUTHOR]

Published
2008

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