Th17, like Tregs, differentiate from CD4+ T cells in the presence of IL-6 and TGF-β [132], and the secretion of IL-17 stimulates the production of pro-inflammatory cytokines such as IL-1, IL-6, and IFN-γ leading to anti-platelet antibody production in mice [131] and in patients with ITP [99,123,129,133,134,135]. The gene discussed is IL17A; the disease is autoimmune thrombocytopenic purpura.