IL-1β promotes the differentiation of Th17 cells to secrete IFN-γ [60], and IL-18 enhances IFN-γ-induced production of C-X-C motif chemokine 9 (CXCL9), CXCL10 and CXCL11 [61], which migrate from dermis to epidermis causing chronic inflammatory activation of psoriasis. The gene discussed is IFNG; the disease is psoriasis.