Elevated circulating levels of the inflammatory cytokines IL-2, IL-17, IL-18 and IFN-γ were statistically significantly correlated with the risk of psoriasis, while no significant correlation was found for the levels of circulating inflammatory factors IL-4, IL-12, IL-22, IL-23, IL-35, IL-36 and TGF-β. The gene discussed is IL18; the disease is psoriasis.