Radovan Košturiak, Miloš Jeseňák
Vitamin D is a steroid-like hormone involved in bone metabolism and calcium homeostasis. However, during the past decades so-called extra skeletal functions have been recognized. Immunoregulation represents one of the newly discovered function of this vitamin. The net effect of vitamin D on non-adaptive part of immune system is stimulatory, mainly due to enhanced expression of antimicrobial peptides and stimulated phagocytosis. On the other hand, further propagation of immune response is limited by inhibition of dendritic cell maturation. The adaptive immunity is down-regulated during the late phase of its activation, so the initial response to pathogens is not compromised. This time dependent effect of vitamin D represents major regulatory feedback in prevention of autoimmunity and chronic inflammatory conditions.