CD4 and autoimmune disease: For example, T-helper 17 (Th17, CD3+CD4+IL17+T) cells, cytotoxic T (Tc17, CD3+CD8+IL17+T) cells and regulatory T (Treg, CD3+CD4+CD25+Foxp3+T) cells are all involved in the pathogenesis of inflammatory and autoimmune diseases.