Down-regulated FcγRII expression on plasma cells is associated with the disease activity of ANCA-associated vasculitis.

OBJECTIVES: Inhibitory FcγRIIB/CD32B on B cells are critical for immunity regulation to help maintain peripheral tolerance. Altered FcγRIIB expression on B cells has been observed in several autoimmune diseases, and animal studies have suggested that FcγRIIB on B cells participates in the pathogenesis of ANCA-associated vasculitis (AAV). Here, we investigated the expression of FcγRII (FcγRIIB) on various B cell subsets and the correlation of FcγRII/CD32 expression with disease activity in AAV patients. MATERIAL AND METHODS: Blood samples of patients with AAV in active stage and in remission were collected. FcγRII/CD32 expressions on various B cell subsets of the whole blood were detected by flow cytometry, and their correlation with clinical and pathological data was analysed. RESULTS: The expression of FcγRII/CD32 on plasma cells was significantly lower in AAV patients in active stage than those in both AAV patients in remission and healthy donors. Furthermore, the expression of FcγRII/CD32 on plasma cells negatively correlated with BVAS and percentages of cellular crescents in renal biopsies. CONCLUSIONS: There is a down-regulation of FcγRIIB/CD32B expression on B cells in patients with AAV, which is associated with the disease activity of AAV.