Decrease in the proportion of CD24hiCD38hi B cells and impairment of their regulatory capacity in type 1 diabetes patients

Summary B10 cells restore immune balance by producing interleukin (IL)-10. Impaired B10 cell responses are related to numerous autoimmune diseases. However, the function of B10 cells in type 1 diabetes (T1D) patients is controversial. We hypothesized that there are numerical and functional defects of B10 cells in T1D. Sixty-two patients with T1D and 74 healthy volunteers were included in our study. We showed that B10 cells in human peripheral blood belong to a CD24hiCD38hi B cell subpopulation. CD24hiCD38hi B cells from healthy individuals possessed regulatory capacity, suppressed interferon (IFN)-γ, tumor necrosis factor (TNF)-α and IL-17A production and promoted IL-4 production and forkhead box protein 3 (FoxP3) expression in CD4+ T cells through an IL-10-dependent mechanism. Compared to healthy controls, B10 cell percentages in T1D were significantly lower (5·6 ± 3·5 versus 6·9 ± 3·3%; P