Recent in vitro and in vivo studies conducted in patients with T2D demonstrated that VIDPP-4i is able to: reduce the expression of pro-inflammatory cytokines (IFN-γ and IL-17); decrease the proliferation of CD4+ T cells and non-CD4+ cells; increase the levels of the anti-inflammatory cytokine IL-4; and upregulate the expression of IL-37 and FOXP3 (Forkhead box protein P3), which are well-known markers for regulatory T cells [92–94]. Here, FOXP3 is linked to type 2 diabetes mellitus.