BACKGROUND AND OBJECTIVE: Nowadays, anti-phospholipase A2 receptor (PLA2R) antibody is recognized as a diagnostic biomarker for idiopathic membranous nephropathy (iMN) and is also used to assess disease progression. Considering the differences in the prevalence of this antibody in various geographic regions, this study aims to evaluate the level of anti-PLA2R antibody in different types of glomerulonephritis and its relationship with proteinuria and creatinine clearance.

METHODS: This cross-sectional study was conducted among 115 patients with diagnosis of glomerulonephritis and nephrotic syndrome. The patients were divided into three categories of iMN (34 patients), secondary membranous nephropathy (9 patients) and other types of glomerulonephritis (72 patients) based on their clinical history and test results. Demographic data, latest creatinine level, volume, protein and the 24-hour urine creatinine were recorded and the creatinine clearance was calculated. The serum level of anti-PLA2R antibody was measured and the level of antibody ≥ 20 RU/ml was considered positive. The level of antibody was compared between the three groups and the relationship between antibody levels and creatinine clearance and proteinuria was assessed in patients with iMN.

FINDINGS: The mean age of the patients was 38±13 years. 81 patients (70%) were female. The mean (SD) antibody level in iMN patients was significantly higher than secondary membranous nephropathy and other types of glomerulopathy (129.9±190.1, 2.6±1.7, 2.0±1.6, respectively, P<0.0001). The antibody level was positive in 47% of the patients with iMN, while it was not positive in any of the other types of glomerulopathy (P<0.001). However, there was no significant relationship between antibody levels and creatinine clearance or 24-hour proteinuria in patients with iMN.

CONCLUSION: Results of the present study demonstrated that the presence of anti-PLA2R antibody specifically indicates idiopathic membranous glomerulonephritis. However, antibody level is not associated with disease severity