Immunomodulatory actions of vitamin D in various immune-related disorders: a comprehensive review

Abstract

For many years, vitamin D has been acknowledged for its role in maintaining calcium and phosphate balance. However, in recent years, research has assessed its immunomodulatory role and come up with conflicting conclusions. Because the vitamin D receptor is expressed in a variety of immune cell types, study into the precise role of this molecule in diseases, notably autoimmune disorders, has been made possible. The physiologically activated version of vitamin D also promotes a tolerogenic immunological condition in addition to modulating innate and acquired immune cell responses. According to a number of recent studies, this important micronutrient plays a complex role in numerous biochemical pathways in the immune system and disorders that are associated with them. Research in this field is still relatively new, and some studies claim that patients with severe autoimmune illnesses frequently have vitamin D deficiencies or insufficiencies. This review seeks to clarify the most recent research on vitamin D's immune system-related roles, including the pathophysiology of major disorders.

Keywords: Vitamin D; acquired immunity; autoimmune disorders; autoimmunity; innate immunity.

Figure 1

The effects of vitamin D on the immune system. Vitamin D and 1,25(OH)2D3 modulate the innate immune response. The regulatory role of this molecule has been shown to affect the innate immune system, such as macrophages, dendritic cells, Nk cells, and ILCs, so, as a critical molecule plays a role in many diseases' pathophysiology. This vitamin also contributes to making an acquired immune response. (See text for additional details). Th, T helper cell; IL, Interleukin; IFN-γ, Interferon-γ.