Since the role of IL-17A has not yet been clearly defined in TA, we proposed to study cell populations that are producers of IL-17A in peripheral blood, that is, Th17 cells, NK cells, NKT cells, and γδ T cells, and serum levels of IL-17A and IL-23 in patients with TA, and looked for their relationship with clinical disease activity. This evidence concerns the gene IL17A and Takayasu arteritis.