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

• Main Authors: 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, Dorottya Csuka
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2021-09-01
• Series: Frontiers in Immunology
• Subjects: membranoproliferative glomerulonephritis; immune complex-mediated glomerulonephritis; C3 glomerulopathy; dense deposit disease (DDD); C3 glomerulonephritis (C3GN)
• Online Access: https://www.frontiersin.org/articles/10.3389/fimmu.2021.720183/full

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.