Clinical and Immunologic Characteristics of Patients With ANCA-Associated Glomerulonephritis Combined With Membranous Nephropathy: A Retrospective Cohort Study in a Single Chinese Center

The concurrent antineutrophil cytoplasmic antibody-associated glomerulonephritis (ANCA-GN) and membranous nephropathy (MN) have been increasingly documented, mainly in case studies and case series; however, the differences of clinical and pathologic characteristics as well as outcomes between ANCA-GN patients with and without MN remain unclear. The current study investigated the clinical and immunologic features of patients with combined ANCA-GN and MN in a large cohort. Twenty-seven of 223 patients had combined ANCA-GN and MN; they had significantly higher levels of initial serum creatinine, higher Birmingham Vasculitis Activity Score and poorer renal outcome than ANCA-GN patients without MN (P < 0.05). ANCA-GN patients with MN could recognize the light chain of myeloperoxidase more frequently than those without MN (P < 0.05). The prevalence of circulating anti-PLA2R antibodies and glomerular PLA2R deposits was significantly lower in patients with combined ANCA-GN and MN than that in patients with idiopathic MN (P < 0.05). Compared with the idiopathic MN patients, the patients with combined ANCA-GN and MN had significantly higher recognition frequency of immunoglobulin (Ig) G2 and IgG3, and significantly lower recognition frequency of IgG4 (P < 0.05). Patients with combined ANCA-GN and MN had distinct clinical features and a different pathogenesis of MN.