Vitamin D, inflammation and immunity: review of literature and considerations on recent translational and clinical research developments

The most relevant and recent literature findings linking exposure to sunlight, Vitamin D (VD), inflammation and immune system in health and disease, are reviewed. Reduced sunlight exposure determined hypo-vitaminosis D to be common among patients or even healthy subjects, especially at higher latitudes. Numerous studies support the hypothesis that VD insufficiency could contribute to the higher autoimmune diseases incidence in the same geographic areas. In the present review, the ways in which VD was reported to influence immune system, contributing to organism homeostasis or disease development are addressed. In fact, some of the hormone activities were recognised to determine stimulation or inhibition of immune system components. Several diseases, where an association with VD deficiency was studied, are summarised. Finally, the rationale for optimization of substitutive/additive therapy with VD analogues and the last innovations regarding these drugs are mentioned.