Vitamin D and Haematopoiesis

Abstract

Abstract Purpose of Review This review examines the influences of active vitamin D on ‘developmental’ haematopoiesis and the immune cells produced. Haematopoiesis gives rise to the platelets, erythrocytes and a wide range of immune cell types each of which performs a specific role to protect the organism from a myriad of infectious agents. The newly produced immune cells, for example, monocytes, dendritic cells and T and B lymphocytes, are activated in response to the presence of an infectious agent and differentiate further to perform their roles. Recent Findings Binding of 1α,25-dihydroxyvitamin D3, the most active metabolite of vitamin D3, to its receptor, the vitamin D receptor, regulates the expression of very many different genes and therefore a mode(s) of action of vitamin D relates to the regulation of expression of cell-specific genes. The haematopoietic cytokines are essential regulators of haematopoiesis and the further maturation and functionality of the immune cell types. We now know that some cytokines also instruct the development of a particular type of blood cell. Summary Vitamin D influences the ‘early’ development of monocytes and invariant natural killer T cells and the further maturation of some immune cell types. Findings regarding the regulation of gene expression have revealed that there are links between the actions of vitamin D and cytokines. Whilst we do not have as yet an entirely clear picture on this matter, there are benefits to ‘health’ of the immune system from vitamin D supplementation.