Ulcerative colitis is characterized by a decrease in regulatory B cells

Abstract

Background and Aims: Ulcerative colitis (UC) is characterized by Th2-polarized, B cell responses. However, neither size, composition, nor activity of the Breg compartment in active UC has been evaluated. Methods: Peripheral blood of 25 patients with UC, 5 patients with Crohn's disease (CD) and 15 control subjects was examined for Bregs subsets by flow cytometry. Intestinal tissue of 5 patients with UC, 3 patients with CD and 5 control subjects was also examined for Bregs. The levels of serum interleukin (IL)-10, immunoglobulin (Ig), and C-reactive protein (CRP), and the erythrocyte sedimentation rate (ESR) in individual subjects were measured. Interleukin-10 production in B cells isolated from patients with UC was examined. Potential associations between the values of the different measures were analysed by the Spearman correlation test. Results: Compared with controls, the UC patients had significantly reduced frequencies of CD24highCD38high and CD5+ Bregs in peripheral blood as well as in intestinal tissues, accompanied by lower serum IL-10 levels. Interleukin-10 production was significantly decreased in stimulated B cells from patients with UC, whereas patient IL-10+ B cells were found to be enriched in CD24highCD38high and CD5+ B cells. However, increased percentages of CD95+-exhausted Bregs were encountered in subsets. Furthermore, Mayo clinic scores, CRP, and ESR in UC patients was negatively correlated with the frequency of Bregs and the IL-10 concentration, whereas these parameters were positively correlated with the frequency of CD95+-exhausted Bregs and the IgG levels. Conclusions: Active UC is characterized by exhaustion of regulatory control in the B cell compartment.