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 (IIF) and a Western blotting test (WB).
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.
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).
ELISA performs excellently in differentiating idiopathic from secondary MN. Furthermore, ELISA shared high agreement with WB and IIF.