While critical in host immunity, Th17 cells which produce pro-inflammatory cytokines, mainly IL-17A, IL-17F, IL-22, and GM-CSF (3) have also been implicated in the pathogenesis of various autoimmune diseases including, psoriasis, psoriatic arthritis, ankylosing spondylitis, uveitis, and multiple sclerosis (4–7). The gene discussed is IL17A; the disease is psoriasis.