Abstract
Primary membranous nephropathy (PMN) is a kidney-specific autoimmune glomerular disease, M-type phospholipase A2 receptor (PLA2R1) is the target antigen. However, the level of PLA2R1 in PMN patients serum remains unclear. Enzyme-linked immunosorbent assay (ELISA) was used to measure PLA2R1, aiming to clarify the diagnostic value and potential clinical significance of PLA2R1 in PMN patients. A total of 115 PMN patients and 35 healthy controls (HCs) from Peking University Third Hospital were enrolled in this study. Spearman correlation, multivariable logistic regression, and receiver operating characteristic (ROC) curve were used for analysis. The PLA2R1 level were significantly higher in PMN patients 67.69 (33.19, 115.14) ng/mL compared to HCs 39.08 (24.74, 50.26) ng/mL (p < 0.001). The ROC analyses revealed that the area under the curve (AUC) of the PLA2R1 level is 0.723 (95% CI: 0.640-0.806) for distinguish PMN patients and HCs, and 0.620 (95% CI: 0.515-0.727) for distinguish PLA2R1-Ab positive and negative PMN patients. Moreover, compared to patients in the PLA2R1 low-level group (PLA2R < 67.69 ng/mL, n = 57), patients in the PLA2R1 high-level group (PLA2R1 ≥ 67.69 ng/mL, n = 58) had a significantly higher level of 24 h urine protein (p = 0.006), serum creatinine (Scr) (p = 0.004), and serum uric acid (SUA) (p = 0.009). Compared to PLA2R1 or PLA2R1-Ab alone, Log (PLA2R1 × PLA2R1-Ab) showed a stronger positively correlation with 24 h urine protein (r = 0.508, p < 0.001), Scr (r = 0.325, p < 0.001), and blood urea nitrogen (BUN) (r = 0.252, p = 0.007). Logistic regression analysis suggested that Log (PLA2R1 × PLA2R1-Ab) is an independent related factor for high-level of proteinuria in PMN patients.