Dynamic Number and Function of IL-10-Producing Regulatory B Cells in the Immune Microenvironment at Distinct Stages of Type 1 Diabetes.

The critical role of IL-10-producing B cells (B10 cells) with a unique CD1dhiCD5+ phenotype in suppressing autoimmune responses and relieving inflammation has been demonstrated in several models of autoimmune diseases. However, the regulatory role of B10 cells in T cell-mediated autoimmune responses during the natural history of type 1 diabetes is unclear. In this study, we used the NOD mouse model of autoimmune diabetes to clarify the changes and potential mechanisms of B10 cells for disease. Compared with B10 cells present in the 4-wk-old normoglycemic NOD mice, the frequency of B10 cells was increased in the insulitis and diabetic NOD mice, with the highest proportion in the insulitis NOD mice. The changes in the relative number of B10 cells were most pronounced in the pancreas-draining lymph nodes. The pathogenic T cells, including Th1 and Th17 cells, remarkably increased. The assays in vitro showed that B10 cells in the NOD mice did not inhibit the proliferation of CD4+CD25- T cells. They also had no regulatory effect on IFN-γ and IL-4 secretion or on Foxp3 expression of T cells. B10 cells suppressed T cell-mediated autoimmune responses via an IL-10-dependent pathway. In contrast, B10 cells in the NOD mice exhibited a significant reduction in IL-10 production. In summary, a defect in the number and function of B10 cells may participate in the development and progression of type 1 diabetes.

B10 cells play a role in the immune modulation of pro- and anti-inflammatory immune responses in mouse islet allograft rejection.

Recently, pancreatic islet transplantation has been shown to be a viable option for the treatment of type 1 diabetes mellitus. However, immune destruction becomes the major impediment to the clinical application of islet transplantation. Here, we evaluated changes affecting multiple types of immune cells and cytokines in allogeneic islet transplantation immunity after the administration of B10 cells alone and explored the regulatory mechanisms of B10 cells in T cell-mediated allograft rejection. In vitro assays, B10 cells significantly decreased the proliferative capacity of CD4+CD25- T cells (13.75%±0.96% vs. 32.76%±0.81%) while enhancing the proliferation of regulatory T cells (Tregs) (26.60%±1.14% vs. 21.52%±0.81%). Furthermore, after the administration of B10 cells in vivo, the frequencies of IL-10+ B cells and Tregs of islet transplant recipients were increased by the CD19+CD5+CD1dhi B cells, and the CD4+/CD8+ and IFN-γ+/IL-17+ ratios were decreased. Serum IL-10 levels were up-regulated, while IFN-γ levels were down-regulated. Grafts from 1 to 5×106 B10 cell-treated recipients exhibited a reduced level of insulitis compared with the untreated controls, although the differences of graft survival times were not statistically significant. In general, in mouse islet allograft rejection, B10 cells may alleviate T cell-mediated immune responses by promoting Treg-cell development and inhibiting Th1 cells activation, via an IL-10-dependent pathway. Development of B10 cell-targeted therapy may be benefit for modulating immune response and provide insight into the signals involved the induction of islet allograft tolerance.

Systematic review and meta-analysis of islet autotransplantation after total pancreatectomy in chronic pancreatitis patients.

Islet autotransplantation (IAT) is a viable treatment for patients with severe chronic pancreatitis, this modality may prevent brittle diabetes mellitus after pancreatectomy. This systematic review and meta-analysis was performed to evaluated the outcomes of IAT after TP and discuss the factors that may affect the efficacy of this procedure. MEDLINE, Embase, Web of Science and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched from 1977 to 30 April 2014. Cohort Studies reported patients with IAT after TP were included. The studies and data were identified and extracted by two reviewers independently. Data were analyzed using STATA 12.0 and Comprehensive Meta AnalysisV2 software. Random effects model, meta-regression analysis, sensitivity analysis and publication bias were conducted to improve the comprehensive analysis. Twelve studies reporting the outcomes of 677 patients were included in this review. The insulin independent rate for IAT after TP at last follow-up was 3.72 per 100 person-years (95% CI: 1.00-6.44). The 30-day mortality was 2.1% (95% CI: 1.2-3.8%). The mortality at last follow-up was 1.09 per 100 person-years (95% CI: 0.21-1.97). Factors associated with incidence density of insulin independence in univariate meta-regression analyses included islet equivalents per kg body weight (IEQ/kgBW) (P=0.026). Our systematic review suggests that IAT is a safe modality for patients with CP need to undergo TP. A significant number of patients will achieve insulin independence for a long time after receiving enough IEQ/kgBW.