Vitamin D inhibits the dysregulated antibody synthesis that is seen in asthmatics. It inhibits the proliferation of immune cells that produce inflammatory substances, and conversely, vitamin D enhances the function and proliferation of regulatory cells, through the induction of IL-10 producing T regulatory cells, and a very effective group of T regulatory cells characterized as CD4+ CD25+ FoxP3+ . Dendritic cell (DC) function is also modulated by Vitamin D. 1,25(OH)2vitaminD3 appears to generate tolerogenic dendritic cells (DC) in vivo, as demonstrated in models of transplantation and autoimmune diseases. Immature/tolerogenic DCs induce development of T regulatory cells by several mechanisms, including production of IL-10 or TGF-beta. Vitamin D3 increases the glucocorticoid receptor expression in asthmatic patients' T cells. In an interesting study on an asthma mouse model, treatment with Vitamin D combined with immunotherapy resulted in increased production of the inhibitory cytokine IL-10 in lung tissue and increased levels of TGF-beta in serum.