Chronic obstructive pulmonary disease is characterized by reduced levels and defective suppressive function of regulatory B cells in peripheral blood

Chronic obstructive pulmonary disease (COPD) is characterized by a progressive, persistent immune response to cigarette smoke, and it has been suggested that immune dysregulation is involved in its pathogenesis. A subset of regulatory B cells (Bregs) with high levels of the surface markers CD24 and CD38 (CD24(hi)CD38(hi)) has previously been shown to exert an immunosuppressive function. This study investigated the levels and activity of CD24(hi)CD38(hi) Bregs in stable COPD (sCOPD). Testing the peripheral blood from 65 patients with sCOPD and 39 control subjects for CD24(hi)CD38(hi) Breg subsets by flow cytometry showed that the patients with sCOPD had significantly lower levels of CD24(hi)CD38(hi) Bregs and IL-10(+) B cells. The patients with sCOPD had lower serum interleukin-10 levels than the controls. The patients with most severe sCOPD had the lowest levels of CD24(hi)CD38(hi) Bregs. Spearman correlation analysis showed that the levels of CD24(hi)CD38(hi) Bregs in the patients with sCOPD positively correlated with serum interleukin-10 concentrations but not with levels of C-reactive protein. Compared to healthy controls, functional studies showed that Breg cells from patients with sCOPD exhibit a decreased suppressive function. We conclude that sCOPD is characterized by the exhaustion of CD24(hi)CD38(hi) regulatory B cells compartment. Therefore, CD24(hi)CD38(hi) Bregs may contribute to the patho-genesis of sCOPD.