The first study to report the effects vitamin D has on the immune system of people with lupus was reported this week a the American College of Rheumatology Annual Scientific Meeting in Chicago.
Systemic lupus erythematosus, also called SLE or lupus, is a chronic inflammatory disease that can affect the skin, joints, kidneys, lungs, nervous system, and/or other organs of the body. The most common symptoms include skin rashes and arthritis, often accompanied by fatigue and fever. Lupus occurs mostly in women, typically developing in individuals in their twenties and thirties - prime child-bearing age.
There is a connection between lupus and the disturbance of regulatory T cells (which play an important role in maintaining a healthy immune system), T helper lymphocytes (white blood cells that assist other white blood cells in the immune system), and B cells (which make antibodies that fight off attacks on the immune system). Vitamin D has been shown to affect the numbers and function of many of these immune cells. Because of this connection, researchers — led by Benjamin Terrier, MD; Patrice Cacoub, MD, PhD; and Nathalie Costedoat-Chalumeau, MD,PhD; from the Internal Medicine Department of the Pitié-Salpétrière Hospital in Paris, France — studied 24 people with lupus to determine their vitamin D status and to determine whether vitamin D supplementation would be well tolerated and potentially beneficial to their immune systems. Only patients with no or mild lupus activity were included in this study.
All of the participants in the study were taking a stable dose of prednisone and/or immunosuppressive drugs. Each participant with vitamin D deficiency received vitamin D supplementation (100,000 IU of cholecalciferol) each week for four weeks followed by the same amount each month for six months. Researchers evaluated each participant at the beginning of the study, at two months, and again at six months to see how well they were tolerating the supplementation and how it was affecting their immune systems. Researchers also analyzed the blood lymphocytes of each participant at the three time-points to monitor the evolution of regulatory T cells, T helper lymphocytes and B cells under vitamin D therapy.
Among the 24 patients in the study, 20 (who were around the age of 30) had low levels of vitamin D and received supplementation. The researchers noted the supplementation was safe, and the participants did not develop too much calcium in their blood or calcium deposits (such as kidney stones).
Serum 25(OH)D levels dramatically increased with vitamin D supplementation - reaching normal values at two months and six months. The clinical activity of lupus did not change significantly, and none of the patients showed a flare of the disease or required an increase in corticosteroids or immunosuppressive drugs. However, the levels of anti-DNA antibodies, which are abnormal and pathogenic antibodies produced by B cells, decreased at two months and six months.
The number of regulatory T cells increased with vitamin D supplementation at both two and six months, with a similar trend for both naïve and activated memory regulatory T cells, which represent two subsets of regulatory T cells. This increase of regulatory T cells was also associated with an increased expression of molecules associated with their suppressive function (i.e., GITR and LAP).
A decrease in T helper lymphocytes, previously shown to be increased in lupus, was noted after two months of vitamin D supplementation. Finally, researchers observed a decrease in memory B cells (which produce antibodies) at two months and in activated CD8+ T cells (which may contribute to the disease process in lupus) at six months. Taken together, these results provide evidence of normalization of abnormal lymphocyte numbers in these patients.
"This preliminary study provides encouraging results and suggests the beneficial role of vitamin D supplementation in patients with SLE, with an increase of regulatory T cells and a decrease of memory B cells and effector T cells," explains Dr. Terrier. "However, these findings need to be confirmed in large randomized controlled trials."
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