Vitamin D: Effect on Haematopoiesis and Immune System and Clinical Applications

Abstract

Vitamin D is a steroid-like hormone which acts by binding to vitamin D receptor (VDR). It plays a main role in the calcium homeostasis and metabolism. In addition, vitamin D display other important effects called "non-classical actions." Among them, vitamin D regulates immune cells function and hematopoietic cells differentiation and proliferation. Based on these effects, it is currently being evaluated for the treatment of hematologic malignancies. In addition, vitamin D levels have been correlated with patients' outcome after allogeneic stem cell transplantation, where it might regulate immune response and, accordingly, might influence the risk of graft-versus-host disease. Here, we present recent advances regarding its clinical applications both in the treatment of hematologic malignancies and in the transplant setting.

Keywords: allogeneic stem cell transplantation; haematopoiesis; leukaemia; myelodysplastic syndrome; vitamin D.

Figure 1

Synthesis of vitamin D and the vitamin D metabolic pathway. The vitamin D metabolites are transported in blood bound primarily to vitamin D binding protein (DBP) (85–88%) and albumin (12–15%).

Figure 2

1,25(OH)₂D3 acts mediating lipid signalling pathways (protein kinase C pathway), phosphatidylinositol-3-kinase (PI3K)-AKT pathway and mitogen activated kinase (MAPK) pathways.