Alterations of peripheral blood CD5+B cells in inflammatory bowel disease

Objective. CD5+ B cells comprise a unique subset of B cells that modulates innate as well as autoimmune systems. The aim of this study was to investigate alterations of the circulating CD5+ B-cell subset in patients with inflammatory bowel disease (IBD) by evaluating various clinical parameters, including therapeutic regimens. Material and methods. Thirty-four patients with ulcerative colitis (UC), 19 patients with Crohn's disease (CD), and 46 healthy control subjects were enrolled in this study. CD5+ B cells in peripheral blood collected from each subject were analyzed by flow cytometry. Multiple regression analysis was carried out to evaluate the factors related to the circulating CD5+ B-cell subset in the IBD patients. In an in vitro examination, dexamethasone-induced apoptosis in peripheral blood B cells was examined by detecting cell surface binding of the annexin-V antibody. Results. Age and gender in the control subjects did not influence the circulating CD5+ B-cell subset. Multiple regression analysis showed that the presence of UC, corticosteroid therapy, and number of white blood cells in peripheral blood each had a significant influence in decreasing the number of circulating CD5+ B cells in the IBD patients. Furthermore, in vitro results showed that dexamethasone treatment significantly induced apoptosis in CD5+ B cells, though apoptosis was similarly observed in CD5- B cells. Conclusions. CD5+ B cells may be involved in the pathogenesis of UC, and modulation of this subset by corticosteroid therapy may play a role in the treatment of IBD patients.