Furthermore, a number of transplant studies have shown that stem cell therapy stimulates murine Treg cells; stimulates iTregs from conventional T cells; increases FOXP3 gene expression; is able to suppress the proliferation, activation, and differentiation of CD4+ T cells and IL-10 secretion; limits Treg conversion to IFN-γ/TNF-α producing T effector cells; and thereby regulates graft versus host disease [66, 67]. Here, CD4 is linked to graft versus host disease.