Diagnostic and Prognostic Value of Anti-Phospholipase A2 Receptor Antibodies in Patients with Membranous Nephropathy

Objective: This study aimed to evaluate the diagnostic and prognostic significance of anti-phospholipase A2 receptor (PLA2R) in primary membranous nephropathy (PMN) patients and determine the most appropriate cut-off value. Methods: Between June 2022 and June 2023, 74 patients who were followed up with PMN, secondary MN, non-MN nephrotic syndrome and 15 healthy volunteers were included. Anti-PLA2R antibody levels were evaluated by enzyme-linked immunosorbent assay (ELISA) (EUROIMMUN, L & uuml;beck, Germany). Receiver operating characteristic (ROC) curve analysis was performed. Results: The ELISA kit showed sensitivity of 30% and specificity of 100% when the cut-off value of 20 relative units (RU)/mL was used. According to the ROC curve analysis, the cut-off value was found to be 1.19 RU/mL. When using this value, sensitivity was 66.6% and specifity was 72.7%. However when cut-off value was used 2 RU/mL, sensitivity and specifity was 46.6% and 100%, respectively. Only part of PMN patients were antibody positive; all other groups were negative. All PMN patients were antibody positive at diagnosis; and as for patients with active disease 25% were positive and 25% were borderline. Whereas for patients with complete and partial remission and 18.8% of these were antibody positive. Anti-PLA2R positive patients had higher mean proteinuria and lower mean albumin. Anti-PLA2R positive PMN patients had lower mean hemoglobin and hematocrit values. Conclusion: Anti-PLA2R may be helpful in diagnosis in PMN patients when secondary causes are well excluded at the time of diagnosis and also be helpful in predicting progression during follow-up.