How was the study conducted?
The study involved the use of paired peripheral blood and synovial fluid from the inflamed joint of patients with RA. “Our current understanding of vitamin D and rheumatoid arthritis is based on studies of patient blood which may not truly represent the situation at the site of inflammation - the joints. We therefore investigated responses to the active form of vitamin D in immune cells from the inflamed joints of patients with rheumatoid arthritis. Compared to blood from the same patients, the inflamed joint immune cells were much less sensitive to active vitamin D. This appears to be because immune cells from the joints of rheumatoid arthritis patients are more committed to inflammation, and therefore less likely to change, even though they have all the machinery to respond to vitamin D” said Professor Martin Hewison from the Institute of Metabolism and Systems Research at the University of Birmingham.