Correlations of the Complement Proteins MASP‐2 and MASP‐3 With Clinical Severity and Short‐Term Outcomes in Primary Membranous Nephropathy Patients

ABSTRACT Aim This study aimed to explore the serum levels of mannose binding lectin‐associated serine protease 2(MASP‐2) and 3(MASP‐3) in primary membranous nephropathy (PMN) patients and its correlation with clinical activity and short‐term prognosis. Methods Serum levels of MASP‐2, MASP‐3 and C5a were measured in 72 PMN patients, 71 IgAN patients and 30 healthy controls via enzyme‐linked immunosorbent assay (ELISA). Correlations between complement activation biomarkers and clinical parameters were analysed using Spearman correlation. Logistic regression analysis was used to identify risk factors for short‐term clinical non‐remission in PMN patients, and the predictive performance of the factors was evaluated using ROC curves and the area under the ROC curve (AUC). Results Serum MASP‐2 levels in the PMN group were lower than in both the healthy control and IgAN groups, while levels in the IgAN group were higher than in the healthy control group. Serum levels of MASP‐3 and C5a in the PMN group were not significantly different from those in the IgAN group. Both patient groups had significantly elevated serum levels of MASP‐3 and C5a compared to the healthy control group. In PMN patients, serum MASP‐3 and C5a levels correlated with clinical indicators such as eGFR, serum creatinine and 24‐h urinary protein. Multivariate logistic regression analysis revealed that serum anti‐phospholipase A 2 receptor antibody (anti‐PLA 2 R‐ab) and MASP‐3 were independent risk factors for the non‐remission of PMN at 12 months. The combined detection of serum MASP‐3 and anti‐PLA 2 R‐ab had a greater AUC for predicting early non‐remission than either factor alone. Conclusion Serum MASP‐3 and C5a can serve as biomarkers reflecting the clinical severity of PMN. The combined detection of serum MASP‐3 and anti‐PLA 2 R‐ab will improve the prediction efficiency of PMN prognosis.