Rheumatoid arthritis is an autoimmune disease that arises because the immune system mistakenly attacks healthy tissue – usually the joints – leading to painful inflammation and swelling.
The disease often affects several joints at the same time, such as the knees, hands and wrists. It inflames the lining of the joint and eventually damages the joint itself. This can lead to long-lasting pain, problems with balance, and physical deformity.
Previous studies have revealed that vitamin D has “potent anti-inflammatory effects”, including the ability to suppress activity in some types of immune system cells that are known to be active in rheumatoid arthritis.
However, a new study has found that once the disease sets in, some types of cell lose their sensitivity to vitamin D.
The researchers explained that previous studies have only used immune cells isolated from blood, and so the impact of vitamin D on immune cells “at the site of active disease was unclear”.
A significant feature of the new study is that it is the first to use immune cells taken from both the blood and from the inflamed joints of people with rheumatoid arthritis.
The researchers found that some types of immune cell responded differently depending on where they were located.
In particular, they found that some types of immune cells taken from inflamed joints were less sensitive to the anti-inflammatory effects of vitamin D than those taken from the blood of the same people.
“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,” explains study author Martin Hewison, a professor at the University of Birmingham.
Although the study was limited to investigating cells in the laboratory, the findings would appear to support the idea that maintaining vitamin D levels might help to prevent rheumatoid arthritis and other inflammatory diseases.
However, they would also suggest that simply taking vitamin D supplements is unlikely to help people with rheumatoid arthritis because their immune cells are already desensitised.
The researchers now want to take the research further and find out why rheumatoid arthritis causes immune cells to become insensitive to vitamin D, and how this might be prevented.
Read more at medicalnewstoday.com
Do you suffer from rheumatoid arthritis? What helps you keep the symptoms at bay?