Abstract:

Objective To explore the correlation of anti-phospholipase A2 receptor (PLA2R) antibody with idiopathic membranous nephropathy (IMN). Methods Clinical data of 110 IMN patients in Department of Nephrology, the First Hospital of Hebei Medical University were retrospectively analyzed. They were divided into antibody-negative group and antibody-positive group based on the anti-PLA2R antibody (anti-PLA2R-Ab) testing before treatment. Differences between the two groups were compared. The correlation of anti-PLA2R antibody titers with clinical efficacy on IMN was analyzed, and relevant factors affecting clinical remission of IMN were identified. Results A total of 89 IMN patients were followed up for 12 months. Compared with the antibody-negative group, IMN patients in the antibody-positive group had significantly increased proteinuria, decreased serum albumin (ALB) and thicker basement membrane (P<0.05). After 12 months of treatment, the IMN remission rate in the antibody-positive group and the antibody-negative group was 69.35% and 88.89%, respectively, and the cumulative remission rate in the antibody- negative group was significantly higher than that in the antibody-positive group (P<0.05). At 3, 6, and 12 months after treatment, the 24-hour urine protein in both groups was significantly lower than that before treatment, and the ALB level was significantly higher than before treatment (P<0.05). ALB level in the antibody-negative group significantly increased at 3 months, and that in the antibody-positive group significantly increased at 6 months (P<0.05). Before and after treatment, there was no significant difference in serum creatinine between groups. With the decrease of anti-PLA2R-Ab titer, the 24 h urine protein of the antibody-positive group gradually decreased, and ALB level increased. Correlation analysis showed that the anti-PLA2R-Ab titer was positively correlated with 24 h urine protein, and the decrease in the anti-PLA2R-Ab titer was prior to the decrease in 24 h urine protein. Serum anti-PLA2R antibody titer, baseline ALB level, urine protein level, age, gender, and blood pressure were introduced in the multivariate Logistic regression model. It is found that the baseline anti-PLA2R antibody titer was an independent risk factor for non-remission of IMN at 12 months of treatment (OR=2.571, 95%CI: 0.983-3.354, P=0.024). Spearman correlation analysis showed that patients with lower anti-PLA2R antibody titers were more likely to be in remission, and the area under the curve (AUC) of baseline anti-PLA2R-Ab titer in predicting 12-month clinical remission of IMN was 0.7781(95%CI: 0.648-0.816, P<0.01), with the sensitivity and specificity of 68.27% and 77.38%, respectively. Conclusion There is a positive correlation between the anti-PLA2R antibody titer and 24-hour urine protein. The baseline anti-PLA2R antibody titer is an independent risk factor for non-remission of IMN. The change from the assessment of proteinuria to that of serum anti-PLA2R antibody titer is helpful to improve the accuracy of diagnosis and prognosis of IMN and reduce the adverse events of immunosuppressive drugs.

Key words: glomerulonephritis, membranous, prognosis, urine protein, anti phospholipase A2 receptor antibody