New study shows how vitamin D affects immune system

Vitamin D affects key cells in the immune system and might influence susceptibility to diseases such as multiple sclerosis, according to new research from the University of Edinburgh in Scotland, which was published recently in Frontiers in Immunology.

By studying cells from both mice and people, the researchers found vitamin D caused dendritic cells to produce more of a molecule called CD31 on their surface, which hindered the activation of T cells.

In healthy people, T cells play a crucial role in helping to fight infections. In people with autoimmune diseases, however, they can start to attack the body's own tissues. The researchers focused on how vitamin D affects a mechanism in the body's immune system, dendritic cells' ability to activate T cells.

The team observed how CD31 prevented the two cell types from making a stable contact, an essential part of the activation process, and the resulting immune reaction was far reduced.

The findings shed light on how vitamin D deficiency may regulate the immune system and influence susceptibility to autoimmune diseases, according to Richard Mellanby, BSc, BVMS, PhD, DSAM, DipECVIM-CA, FRCVS, a professor at the University of Edinburgh's Centre for Inflammation Research.

"Low vitamin D status has long [been] implicated as a significant risk factor for the development of several autoimmune diseases,” said Mellanby, in a statement released by the university. “Our study reveals one way in which vitamin D metabolites can dramatically influence the immune system."