title: Clinical usefulness of autoantibodies to M-type phospholipase A2 receptor (PLA2R) for monitoring disease activity in idiopathic membranous nephropathy (IMN).
abstract: Autoantibodies to M-type phospholipase A2 receptor (PLA2R) are specific markers of idiopathic membranous nephropathy (IMN). They can differentiate IMN from other glomerular diseases and primary from secondary forms of MN. Preliminary data suggest that anti-PLA2R antibody titer correlates with disease activity but more solid evidence is needed. To evaluate the performance of anti-PLA2R antibody for monitoring nephropathy activity, 149 anti-PLA2R antibody measurements were performed during the follow-up of 42 biopsy proven IMN consecutive patients. Patients were enrolled either at time of diagnosis (33 cases, inception cohort) or after diagnosis (9 patients, non-inception cohort). Anti-PLA2R detection was performed using the highly sensitive transfected cell-based indirect immunofluorescence (IIFT). Over the follow-up there was a linear time-trend of decreasing proteinuria (P<0.001), increasing serum albumin (P<0.001) and decreasing PLA2R antibody levels (P=0.002). There was a statistically significant association between changes in PLA2R antibody levels and the clinical course of PLA2R-positive IMN. The positive PLA2R serum antibody status was linearly associated with increasing proteinuria and decreasing serum albumin over time, compared with negative antibody status. Moreover, the strong correlation between the clinical conditions and PLA2R antibody levels allowed the prediction of prevalence distribution of patients with active disease, partial and complete remission. Over the course of the follow-up, the probability of halving proteinuria increased 6.5 times after disappearance of PLA2R antibodies. Our data suggest that the serial evaluation of anti-PLA2R antibodies could help in optimal timing and duration of the immunosuppressive therapy, reducing over(under)-treatment and associated side-effects.
authors.affiliation: Microbiology and Virology Department, S. Carlo Borromeo Hospital, Milano, Italy. Electronic address: Radice.Antonella@sancarlo.mi.it.
authors.forename: Antonella
authors.initials: A
authors.lastname: Radice
authors.affiliation: Clinical Immunology & Renal Unit, S. Carlo Borromeo Hospital, Milano, Italy; Renal Unit, S. Carlo Borromeo Hospital, Milano, Italy. Electronic address: barbara.trezzi83@gmail.com.
authors.forename: Barbara
authors.initials: B
authors.lastname: Trezzi
authors.affiliation: Nephrology & Transplant, Maggiore Hospital Parma University, Italy. Electronic address: umberto_maggiore@hotmail.com.
authors.forename: Umberto
authors.initials: U
authors.lastname: Maggiore
authors.affiliation: IRCCS Istituto Auxologico Italiano, Milano, Italy. Electronic address: francesca.pregnolato@gmail.com.
authors.forename: Francesca
authors.initials: F
authors.lastname: Pregnolato
authors.affiliation: Renal Unit, S. Gerardo Hospital, Monza, Italy. Electronic address: tizistellato@tiscali.it.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Stellato
authors.affiliation: Renal Unit, S. Carlo Borromeo Hospital, Milano, Italy. Electronic address: pietronapodano@virgilio.it.
authors.forename: Pietro
authors.initials: P
authors.lastname: Napodano
authors.affiliation: Nephrology, S. Martino Hospital, Genova, Italy. Electronic address: davide.rolla@hsanmartino.it.
authors.forename: Davide
authors.initials: D
authors.lastname: Rolla
authors.affiliation: Autoimmunity Laboratory-DIMI, Genova University, Italy. Electronic address: pescegpl@unige.it.
authors.forename: Gianpaola
authors.initials: G
authors.lastname: Pesce
authors.affiliation: Nephrology, S. Anna Hospital, Como, Italy. Electronic address: marco.damico@hsacomo.org.
authors.forename: Marco
authors.initials: M
authors.lastname: D'Amico
authors.affiliation: Nephrology, Messina University, Italy. Electronic address: dsantoro@unime.it.
authors.forename: Domenico
authors.initials: D
authors.lastname: Santoro
authors.affiliation: Nephrology, S. Andrea Hospital, La Spezia, Italy. Electronic address: londrinofrancesco@libero.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Londrino
authors.affiliation: Renal Unit, Niguarda-Cà Granda Hospital, Milano, Italy. Electronic address: federicaravera@yahoo.it.
authors.forename: Federica
authors.initials: F
authors.lastname: Ravera
authors.affiliation: Microbiology and Virology Department, S. Carlo Borromeo Hospital, Milano, Italy. Electronic address: ortisi.giuseppe@sancarlo.mi.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ortisi
authors.affiliation: Clinical Immunology & Renal Unit, S. Carlo Borromeo Hospital, Milano, Italy; Renal Unit, S. Carlo Borromeo Hospital, Milano, Italy. Electronic address: renatoalberto.sinico@fastwebnet.it.
authors.forename: Renato Alberto
authors.initials: RA
authors.lastname: Sinico
mesh_terms: D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D001706:Biopsy; D015433:Glomerulonephritis, Membranous / Q000175:diagnosis* / Q000276:immunology*; D006801:Humans; D054507:Receptors, Phospholipase A2 / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D054507:Receptors, Phospholipase A2
keywords: Autoantibody; Biomarker; Membranous nephropathy; Phospholipase A2 receptor; Proteinuria