The new insights from DPP-4 inhibitors: their potential immune modulatory function in autoimmune diabetes.

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a new class of anti-diabetic agents that are widely used in clinical practice to improve glycemic control and protect β-cell function in patients with type 2 diabetes. DPP-4 is also known as lymphocyte cell surface protein CD26 and plays an important role in T-cell immunity. Autoimmune diabetes, a T-cell mediated organ-specific disease, is initiated by the imbalance between pathogenic and regulatory T-lymphocytes. DPP-4 inhibitors can suppress pathogenic effects of Th1 and Th17 cells and up-regulate Th2 cells and regulatory T cells, which play a critical role in ameliorating autoimmune diabetes. This provides a basis for the potential use of DPP-4 inhibitors in the treatment of autoimmune diabetes. Recent studies suggest that DPP-4 inhibitors improve β-cell function and attenuate autoimmunity in type 1 diabetic mouse models. However, there are few clinical studies on the treatment of autoimmune diabetes with DPP-4 inhibitors. Further studies are warranted to confirm the therapeutic effects of DPP-4 inhibitors on autoimmune diabetes in humans.