Evaluation of Anti-PLA2R1 as Measured by a Novel ELISA in Patients With Idiopathic Membranous Nephropathy A Cohort Study

Objectives: Autoantibodies against the M-type phospholipase A2 receptor 1 (anti-PLA2R1) have been demonstrated to be very specific for idiopathic membranous nephropathy (MN). We studied a novel enzyme-linked immunosorbent assay (ELISA) and compared results with results obtained using an indirect immunofluorescence (IF) and a Western blotting test (WB). Methods: One-hundred nine patients with idiopathic MN were recruited between November 1979 and March 2011. The control cohort comprised serum samples from patients with secondary MN (n = 16) and nephrotic controls (n = 17). The presence of anti-PLA2R1 in serum samples obtained at the time of renal biopsy was determined using ELISA, IIF, and WB. Results: With similar specificity (>= 97%), sensitivity varied from 68% (IIF) to 72% (ELISA, WB). Remarkably, patients who were seronegative for anti-PLA2R1 more often entered spontaneous remission (P = .038), whereas seropositive patients were more frequently treated with immunosuppressive agents (P <.001). Conclusions: ELISA performs excellently in differentiating idiopathic from secondary MN. Furthermore, ELISA shared high agreement with WB and IIF.