VITAMIN D IMMUNOMODULATORY EFFECT

In addition to the classical role in the homeostasis of calcium and phosphorus, vitamin D shows a regulatory effect on a number of different cells, especially its antiproliferative and pro-differential biological function. Through its own receptor in the immune cells, vitamin D increases the phagocytic activity of macrophages and NK cells. Also, by binding to the regulatory sequences of antimicrobial peptides genes, vitamin D increases the microbicidal activity of phagocytes. Inhibition of differentiation and maturation of antigen-presenting dendritic cells, as well as direct influence on their contact with T lymphocytes, it significantlly influences the type of immune response. Dendritic cells under the influence of vitamin D induce a suppressor T cells, which can inhibit Th1 cell response and are critical in the regulation of immune tolerance. Vitamin D inhibits proliferation of Th1 and Th17 cells, as well their cytokine production, and suppresses the differentiation and maturation of B lymphocytes. Due to all these functions, vitamin D has shown beneficial effects in the prevention and modification of a number of autoimmune diseases. On the other hand, immunity disorders with predominant Th2 response (asthma, allergies) did not show such good results after the use of hypocalcemic VDR agonists.