In cellular and molecular pathology, psoriasis is regarded as a T cell-mediated skin disease, involving both T-helper (Th)1 and Th17 cells to promote inflammation by producing cytokines, including TNF-α interferon (IFN)-γ, interleukin (IL)-12, IL-17A, IL-22, and IL-23 [9,10]. The gene discussed is IL17A; the disease is psoriasis.