Chronic obstructive pulmonary disease is characterized by reduced levels and defective suppressive function of...

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^hiCD38^hi) has previously been shown to exert an immunosuppressive function. This study investigated the levels and activity of CD24^hiCD38^hi Bregs in stable COPD (sCOPD). Testing the peripheral blood from 65 patients with sCOPD and 39 control subjects for CD24^hiCD38^hi Breg subsets by flow cytometry showed that the patients with sCOPD had significantly lower levels of CD24^hiCD38^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^hiCD38^hi Bregs. Spearman correlation analysis showed that the levels of CD24^hiCD38^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^hiCD38^hi regulatory B cells compartment. Therefore, CD24^hiCD38^hi Bregs may contribute to the pathogenesis of sCOPD.