CD4 and type 2 diabetes mellitus: Metformin, a well-tolerated drug commonly used to treat type II diabetes [164], inhibits mTOR signaling by activating the AMP-activated protein kinase (AMPK) pathway, promoting autophagy and improving CD4+ T cell counts in diabetic PLWH under cART [161,162].; They recruited 22 nondiabetic PLWH with suppressed viral load for at least three years and a CD4+/CD8+ T cell ratio below 0.7.