title: Cross-reactivity of anti-PLA2R1 autoantibodies to rabbit and mouse PLA2R1 antigens and development of two novel ELISAs with different diagnostic performances in idiopathic membranous nephropathy.
abstract: About 70% of patients with idiopathic membranous nephropathy (iMN) have autoantibodies to the phospholipase A2 receptor PLA2R1. We screened sera from iMN patients for their cross-reactivity to human (h), rabbit (rb) and mouse (m) PLA2R1 by western blot (WB) and antigen-specific ELISAs. All iMN patients recognized hPLA2R1 and rbPLA2R1 by WB, and a rbPLA2R1 ELISA was as sensitive as the standardized hPLA2R1 ELISA to monitor anti-PLA2R1 in patients with active disease or in drug-induced remission. In contrast, only 51% of patients were reactive to mPLA2R1 by WB, and a maximum of 78% were weakly to highly positive in the mPLA2R1 ELISA, suggesting that iMN patients exhibit different subsets of anti-PLA2R1 autoantibodies against epitopes that are shared or not among PLA2R1 orthologs. In a cohort of 41 patients with a mean follow-up of 42 months from anti-PLA2R1 assay, the detection of anti-mPLA2R1 autoantibodies was an independent predictor of clinical outcome in multivariate analysis (p = 0.009), and a ROC curve analysis identified a threshold of 605 RU/mL above which 100% of patients (12 patients) had a poor renal outcome (p < 0.001). A similar threshold could not be defined in hPLA2R1 and rbPLA2R1 ELISAs. We conclude that rbPLA2R1 is an alternative antigen to hPLA2R1 to measure anti-PLA2R1 in active disease while mPLA2R1 is a unique antigen that can detect a subset of anti-PLA2R1 autoantibodies present at high levels (>605 RU/mL) only in iMN patients at risk of poor prognosis, and is thus useful to predict iMN outcome.
authors: Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275 CNRS and Université de Nice-Sophia Antipolis, Valbonne Sophia-Antipolis, France; Service de Néphrologie, Hôpital Pasteur, Université de Nice-Sophia Antipolis, France; Laboratoire d'Immunologie, Hôpital l'Archet, Université de Nice-Sophia Antipolis, France. Electronic address: seitz-polski.b@chu-nice.fr.
authors: Barbara
authors: B
authors: Seitz-Polski
authors: Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275 CNRS and Université de Nice-Sophia Antipolis, Valbonne Sophia-Antipolis, France.
authors: Guillaume
authors: G
authors: Dolla
authors: Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275 CNRS and Université de Nice-Sophia Antipolis, Valbonne Sophia-Antipolis, France.
authors: Christine
authors: C
authors: Payré
authors: Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275 CNRS and Université de Nice-Sophia Antipolis, Valbonne Sophia-Antipolis, France; University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors: Nicola M
authors: NM
authors: Tomas
authors: Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275 CNRS and Université de Nice-Sophia Antipolis, Valbonne Sophia-Antipolis, France; Service de Néphrologie, Hôpital Pasteur, Université de Nice-Sophia Antipolis, France; Laboratoire d'Immunologie, Hôpital l'Archet, Université de Nice-Sophia Antipolis, France.
authors: Marine
authors: M
authors: Lochouarn
authors: Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275 CNRS and Université de Nice-Sophia Antipolis, Valbonne Sophia-Antipolis, France.
authors: Louise
authors: L
authors: Jeammet
authors: Service de Néphrologie Dialyse Transplantation Rénale, CHU Hôpital Nord, Saint-Etienne, and Université de Saint-Etienne PRES Université de Lyon, Saint-Etienne, France.
authors: Christophe
authors: C
authors: Mariat
authors: Service de Néphrologie, CHU de Strasbourg, Strasbourg, France.
authors: Thierry
authors: T
authors: Krummel
authors: Service de Néphrologie Dialyse Transplantation Rénale, Assistance Publique-Hôpitaux de Marseille, Hôpital de la Conception, UMR S1076, Université Aix-Marseille, Marseille, France.
authors: Stéphane
authors: S
authors: Burtey
authors: Service de Néphrologie Dialyse Transplantation Rénale, CHU Saint-Jacques, Besançon, France.
authors: Cécile
authors: C
authors: Courivaud
authors: EUROIMMUN AG, Lübeck, Germany.
authors: Wolfgang
authors: W
authors: Schlumberger
authors: Centre de Recherche Clinique, Hôpital l'Archet, Université de Nice-Sophia Antipolis, France.
authors: Kévin
authors: K
authors: Zorzi
authors: Laboratoire d'Immunologie, Hôpital l'Archet, Université de Nice-Sophia Antipolis, France.
authors: Sylvia
authors: S
authors: Benzaken
authors: Laboratoire d'Immunologie, Hôpital l'Archet, Université de Nice-Sophia Antipolis, France.
authors: Ghislaine
authors: G
authors: Bernard
authors: Service de Néphrologie, Hôpital Pasteur, Université de Nice-Sophia Antipolis, France.
authors: Vincent L M
authors: VL
authors: Esnault
authors: Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275 CNRS and Université de Nice-Sophia Antipolis, Valbonne Sophia-Antipolis, France. Electronic address: lambeau@ipmc.cnrs.fr.
authors: Gérard
authors: G
authors: Lambeau
mesh_terms: D000818:Animals; D001323:Autoantibodies / Q000276:immunology*; D001324:Autoantigens / Q000276:immunology*; D015153:Blotting, Western; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D015433:Glomerulonephritis, Membranous / Q000175:diagnosis*; D006801:Humans; D011817:Rabbits; D054507:Receptors, Phospholipase A2 / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; C516360:PLA2R1 protein, human; C516357:Pla2r1 protein, mouse; D054507:Receptors, Phospholipase A2
keywords: Autoimmunity; Conformational epitope; ELISA; Membranous nephropathy; Mouse PLA2R1; Orthologs; PLA2R1 autoantibodies; Rabbit PLA2R1