Scientists at two universities in the United Kingdom have found rheumatoid arthritis (RA) sufferers lose their sensitivity to vitamin D which may play a big role in the condition. The team comprised of researchers from both the University of Birmingham University and the College London published their finding in the Journal of Autoimmunity.
Rheumatoid arthritis is an autoimmune disease of the joints whereby the immune system attacks regular healthy tissue for no apparent reason. It causes swelling, inflammation and pain, mostly in the hands and fingers, but also in the knees. Long term it can deform the joints of the hands and cause severe balance and problems with walking and climbing stairs.
This newest study is one of the first to employ immune cells from blood and inflamed arthritic joints, thereby enlarging the study and its results. In previous papers these researchers demonstrated that Vit D exhibited powerful anti-inflammatory properties and could decrease immune system T activity found in RA.
Senior study author Karim Raza, a professor in the Institution of Inflammation and Ageing at the University of Birmingham, say that they looked at immune cells from the actual arthritis joint and the blood to determine if the subsets of T-cells had the same sensitivity to Vit D.
Samples of synovial fluid was extracted from the joints of 15 RA patients between 40 and 85 years of age, as well as their blood and compared to non-RA blood donor volunteers matched to age and gender. Their findings revealed that some T cells from inflamed joints were less reactive to the anti-inflammatory properties of Vit D than were the blood samples from the same people.
Study author Martin Hewison, a professor in the University of Birmingham’s Institute of Metabolism and Systems Research believes immune cells from the joints are tenacious and therefore resist change from Vit D more vigorously. While this laboratory investigation is somewhat limited the team feels that higher levels of Vit D should transfer to helping fight RA and other inflammatory disorders in the real world, but only in high doses. This would appear to be the case because the already desensitized RA joints would initially disregard smaller daily doses, notes study co-author Dr. Louisa Jeffery. The researchers were surprised to find there was less response to Vit D in the joint as opposed to a greater response in the blood of the same RA patient.
More research is needed to determine why RA and other inflammatory disorders allow decreased sensitivity to Vit D by the immune cells, and therefore be able to prevent it.
As an additional note, researchers are exploring why RA sufferers are more likely to develop COPD (chronic obstructive pulmonary disease) wherein there is airway damage to the lungs making breathing harder, similar to but different from asthma.
