Serum PLA2R-IgG4/PLA2R-IgG ratio dynamics reveal pathogenic autoantibody subclass switch during progression of PLA2R-associated membranous nephropathy

Abstract

Background: Pathogenic autoantibody subclass switch has been found in lots of autoimmune disease. However, the information on anti-phospholipase A2 receptor antibody subclass switch in membranous nephropathy (MN) is limited and controversial. Here, we aim to uncover the subclass change during the PLA2R-associated MN progression. Methods: Biopsy-proven PLA2R-associated MN cases with sufficient tissue for light microscopy, immunofluorescence, and electron microscopy (October 2022 - March 2023) were included. Serum levels of PLA2R-IgG4 and PLA2R-IgG were measured by TRFIA. The correlation of the ratio with EM stage and other clinical parameters was analyzed. Results: Among 116 enrolled patients, glomerular IgG1 (r = 0.15, p = .01; r = 0.18, p = .002) and IgG3 (r = 0.17, p = .005; r = 0.27, p