DPP4 and type 2 diabetes mellitus: Based on previous evidences pertaining to tumour microenvironment induced changes in T cells and other studies on T2DM which point towards an exhaustive phenotype, these changes in T cell metabolism and function can most probably be attributed to chronic activation induced T cell exhaustion.34 A study reported that CD26 expression was significantly decreased while ADA activity was significantly increased in T2DM patients which could also explain altered lymphocyte function in T2DM.35