NMU 132 – Vit D Decreases Autoimmune via Dendritic Cells
Nutrition / Natural Medicine Update No 132 (June 13, 2019)
with Dr. James Meschino
Topic: How Vitamin D Helps Tame Autoimmune Disease: Newly Discovered Mechanism
Source: Frontiers in Immunology (March 2019)
Approximately 6% of the population suffers from one of the 50 autoimmune diseases that afflict humans. In autoimmune disease, the immune system begins attacking normal body tissues. New drugs have been developed in recent years that have improved the management of various autoimmune conditions, including lupus and rheumatoid arthritis. In addition to medications, many rheumatologists now include vitamin D supplementation in their standard treatment for certain autoimmune diseases. Vitamin D has been shown in recent years to have a direct influence on a type of immune cell, called dendritic cells, which are the main drivers of autoimmune disease when they act in an aberrant way. More specifically, vitamin D has been shown to inhibit the synthesis and expression of co-stimulatory molecules and specific receptors on dendritic cells that promote the inflammatory process of the immune system in the autoimmune process. By inhibiting the secretion and expression of these inflammation-promoting molecules and receptors on dendritic cells, vitamin D helps to tame the autoimmune disease process. Thus, vitamin D supplementation can be an important modulator of certain autoimmune conditions.
In the March issue of the journal Frontiers in Immunology, researchers published data showing one other important way by which vitamin D helps to regulate dendritic cells, slowing and/or arresting key aspects of the autoimmune process. They discovered that vitamin D also encourages dendritic cells to also produce a molecule on its surface known as the CD31 adhesion molecule. The presence of CD31 on the surface of the dendritic cell sends a direct anti-inflammatory message to another immune cell, the CD4 cell, which is the quarterback of the entire immune system. In autoimmune disease, dendritic cells and other immune cells somehow stimulate CD4 cells to morph into aggressive immune cells (such as the CD17 cell) that secrete copious amounts of inflammatory chemicals (cytokines) that prompt many other immune cells to generate massive amounts of inflammatory and other tissue destroying agents and assault weapons that attack the body’s normal tissues. By increasing the expression of CD31 molecules on the surface of dendritic cells, vitamin D indirectly inhibits CD4 cells (the quarterback of the entire immune response) from issuing instructions to other immune cells to attack normal body tissues. This is because CD31 acts as an inhibitory signaling messenger on CD4 cells, thereby arresting the inflammatory process of the entire immune system to a certain degree.
One of the rheumatologists that I have worked with typically recommends 2,000 IU per day of vitamin D to her patients. In certain situations, higher doses may be even more beneficial. It depends on the type of autoimmune disease and the patient’s current vitamin D blood level. What is noteworthy is that individuals with low vitamin D blood levels are known to be at higher risk for developing an autoimmune disease. For prevention, my recommendation is to ensure that you keep your vitamin D blood level between 80 and 150 nmol/L (32 – 60 ng/ml).
I have included the research reference for this published paper in the text below.
Louise Saul, Iris Mair, Alasdair Ivens, Pamela Brown, Kay Samuel, John D. M. Campbell, Daniel Y. Soong, Nadine Kamenjarin, Richard J. Mellanby. 1,25- dihydroxyvitamin D3 Restrains CD4 T Cell Priming Ability of CD11c Dendritic Cells by Upregulating Expression of CD31. Frontiers in Immunology, 2019; 10.3389/fimmu.2019.00600
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