CD4 and autoimmune disease: CD4+CD28− T cells, virtually absent from peripheral blood of healthy individuals but present in acute coronary syndrome and rheumatoid vasculitis [29], multiple sclerosis [14] and, most important here, in end-stage renal disease [30], [31], were found to be resistant to immunoregulation [14] and therefore postulated to play a role in autoimmune diseases and aging [12].