Sitagliptin, a DPP-4 inhibitor, alters the subsets of circulating CD4+ T cells in patients with type 2 diabetes

Highlights • 12-Week treatment with sitagliptin reduced the number of total CD4+ cells in type 2 diabetes. • The number of circulating T-helper 17 and regulatory T cells were decreased by sitagliptin. • The number of total CD4+ cells was not altered in the glimepiride group. • Sitagliptin decreases the number of the subsets of CD4+ T cells in a glucose-independent manner. • A reduction in circulating CD4+ T cells or Treg cells by sitagliptin may be associated with increased risks of severe arthritis in people with diabetes.