The most frequent CD4+-T-cell subtypes are: interferon-gamma (IFN-ɣ)-secreting Th1 cells, typically involved in chronic inflammation and anti-viral immunity; Th2 cells, which support allergic responses and immunity against metazoan parasites (e.g., Ascaris lumbricoides) and also promote immunosuppression; Th17 cells releasing IL-17 in response to fungal or bacterial infection and promoting autoimmunity [2]; Treg cells that suppress effector-T-cell functions, dampening inflammation and preventing the development of autoimmune diseases [3]. Here, CD4 is linked to autoimmune disease.