Focusing on three major proinflammatory cytokines (IL-17A, IL-22, and IL-23) responsible for development of psoriasis, the secretion of IL-17A, IL-22, and IL-23 in the culture supernatants of cells stimulated with TNF-α and IFN-γ, with or without the presence of WCR, was quantitatively evaluated by ELISA. Here, IFNG is linked to psoriasis.