Vitamin D  deficiency may make people more vulnerable to Multiple Sclerosis

Researchers at the University of Edinburgh have discovered in a new study that Vitamin D significantly affects the immune system and its deficiency could make people more susceptible to diseases such as multiple sclerosis. The study has been published in the journal Frontiers in Immunology.

Apart from its classical function in bone and calcium metabolism, vitamin D is also involved in immune regulation and has been linked to various cancers, immune disorders and allergic diseases. Scientists have conducted the present study to shed light on how vitamin D deficiency may influence the risk of autoimmune diseases.

The body produces vitamin D in response to sunlight and the scientists investigated how it affects a mechanism in the immune system – dendritic cells' ability to activate T cells.

In healthy people, T cells play a crucial role in helping fight infection, but in people with autoimmune diseases, they can start to attack the body's own tissues.

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

Professor Richard Mellanby, of the University of Edinburgh's Centre for Inflammation Research, said: "Low vitamin D status has long been implicated as a significant risk factor for the development of several autoimmune diseases.

"Our study reveals one way in which vitamin D metabolites can dramatically influence the immune system."