Regulatory subsets of B cells (Bregs) modulate immune responses in autoimmunity, cancer, and other inflammation diseases. In the present study, we investigated the numbers of circulating Breg cells in patients with rheumatoid arthritis (RA). We evaluated 59 RA patients and 25 healthy controls. CD19(+)CD5(+)CD1d(hi) B cells and granzyme B-secreting B cells (CD19(+)CD5(+)GzmB(+)) were analyzed by flow cytometry in peripheral blood mononuclear cells. We detected serum interleukin 10 (IL-10), interleukin 21 (IL-21), granzyme B (GzmB) using enzyme-linked immunosorbent assay (ELISA). Compared to control subjects, we found a decreased proportion of CD19(+)CD5(+)CD1d(hi) B cells in RA patients. The number of CD19(+)CD5(+)CD1d(hi) B cells negatively correlated with DAS28 (P??0.05, all). Interestingly, IL-21 and GzmB levels positively correlated in RA patients (P?