CD4 and graft versus host disease: The metabolic inhibitors, 2-DG and 3-PO, as well as rapamycin, which have been reported to attenuate GvHD through T cell metabolic reprogramming and modulation of CD4+ T cell differentiation [19,56,69,86,87,92], are also candidates for macrophage downregulation in GvHD therapy given M1’s dependence on glycolysis and M2’s dependence on OXPHOS, respectively.