In addition, vitamin D may reduce the risk of psoriasis by inhibiting T-cell proliferation/Th1 development, tempering antigen presenting cell (APCs) function, bringing hypo-responsiveness to antigens, decreasing the levels of IL-2, IL-17, IL-8, INF-α and INF-γ, enhancing manufacture of IL-10 and regulatory T cells [5, 6]. The gene discussed is CXCL8; the disease is psoriasis.