Combination of vitamin D and dipeptidyl peptidase-4 inhibitors (VIDPP-4i) as an immunomodulation therapy for autoimmune diabetes

•Vitamin D and DPP-4 inhibitors exert synergistic anti-inflammatory and immunomodulatory actions.•Pre-clinical evidence suggests that vitamin D and DPP-4 inhibitors may prevent or delay the onset of diabetes or halt disease progression.•Vitamin D plus DPP-4i combination therapy (VIDPP-4i) has the potential ability to preserve beta-cell function in autoimmune diabetes.•Randomized controlled trials are warranted to establish the efficacy of VIDPP-4i as an immunomodulation therapy in autoimmune diabetes.