Regulatory effects of 1α,25-dihydroxyvitamin D3 on inflammatory responses in psoriasis

Topical application of 1 alpha, 25-dihydroxyvitamin D-3 (VD3) is thought to be beneficial in psoriasis because of its action in regulating keratinocyte proliferation and inflammation mediated by various cytokines. Wt: assessed the effect of VD3 on the production levels of interferon (IFN)-gamma, interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)-alpha in mitogen-stimulated peripheral blood mononuclear cells (PBMC) of psoriatic patients. The results demonstrated that VD3 significantly inhibited IFN-gamma, IL-6, and IL-8 levels produced by concanavalin A (Con A)-stimulated PBMC of psoriatic patients in a dose-dependent manner, and reduced mRNA expression or IFN-gamma and IL-8. These findings suggest that in addition to the direct anti-proliferation effect on keratinocytes, VD3 may down-regulate the inflammatory cytokine production by infiltrating cells in psoriatic lesions.