Anti-Phospholipase A2 Receptor Antibodies Correlate with Clinical Status in Idiopathic Membranous Nephropathy

Background and objectives Circulating autoantibodies against the M-type phospholipase A(2) receptor (anti-PLA(2)R) were recently identified in the majority of patients in the United States with idiopathic membranous nephropathy (iMN). The objectives of this study were to assess the prevalence of anti-PLA(2)R in a separate, European cohort of iMN patients and to correlate the presence of anti-PLA(2)R with clinical parameters reflective of disease activity. Design, setting, participants, & measurements Anti-PLA(2)R levels were blindly assessed by a Western blot immunoassay in 54 serum samples from 18 patients with iMN collected in various stages of clinical disease. Anti-PLA(2)R levels were correlated with other clinical parameters. Results 77.8% of iIVIN patients in our cohort had antibodies reactive with human PLA(2)R. The antibody levels in these patients correlated strongly with both clinical status and proteinuria (r = 0.73, P < 0.01). Conclusions The role of PLA(2)R as a major antigen in iMN was confirmed in an independent, European patient cohort, and levels of circulating anti-PLA(2)R revealed a strong correlation with clinical disease activity. We propose that detection and measurement of these autoantibodies may provide a tool for monitoring of disease activity and treatment efficacy. Clin J Am Soc Nephrol 6: 1286-1291, 2011. doi: 10.2215/CJN.07210810