A bright example is autoimmunity, in which abnormal Treg function or numbers are associated with the transcription factors GATA3 [54] and Tbet [55], the chemokines CXCR3 [56] and CXCR5 [57], and the cytokines interferon gamma [58], interleukin 5 [59], interleukin 4 [60], and interleukin 17 [61]. The gene discussed is IL17A; the disease is Autoimmunity.