B Lymphocyte Subset Changes in Primary Membranous Nephropathy

BackgroundPrimary membranous nephropathy (PMN) is an autoimmune disease affecting renal glomerulus, characterized by autoantibodies aggregation on podocytes and subsequent epithelial thickening. Therefore, rituximab, an anti-CD20 monoclonal antibody, is used to treat patients with the deteriorating condition.ObjectivesAssuming that rituximab demolishes a considerable number of B-lymphocytes and causes transient immunodeficiency, we aimed to identify B cell subsets involved in PMN pathogenesis to facilitate specific targeting.MethodsUsing flowcytometery, 25 PMN patients including 15 on standard treatment and 10 on standard treatment plus rituximab were enrolled to compare with healthy controls. Rituximab-receiving patients were studied before and two months after administration.ResultsNeither total CD19+ nor memory B cell percentages showed significant differences between the study groups. However, the number of B regulatory cells (Breg) was lower in both standard-treatment and Rituximab-receiving patients than in controls. Moreover, the percentage of naive/mature B cells dropped after standard treatment.ConclusionsPMN patients seem to possess an insufficient percentage of Breg cells, which are involved in immunomodulation. Furthermore, the standard-treatment group showed a reduced count of naive/mature B cells, which constitute a substantial proportion of normal B lymphocytes population.