The debilitating effects that rheumatoidarthritis (RA) can cause tend to occur in the same joints as before. This is true even if it's been a long time since the last flare-up.
New research on mice suggests that this may be due to the fact that our immune system keeps a track of past ailments, creating a personal disease pattern for each person. This could lead to new treatments and opportunities.
The immune system's key cells, the T cells, are the focus of this latest study. The T cells found in the synovium, which is the inner capsule surrounding each joint, appear to have a memory of past RA issues.
Peter Nigrovic, an immunologist at Boston Children's Hospital, says that most flares are in previously involved joints. "Something in the joint seems to recall, 'this was the joint that flared before.'
"We found that T cells are anchored in the joints by our research and stay there indefinitely until the next trigger. These cells can be deleted and arthritis flares will stop.
Two mouse models that used chemical triggers to induce joint inflammation, and one model that used a genetic trigger to produce the same effect were tested. The researchers removed a protein which blocked the pro-inflammatory cytokine IL-1.
These triggers caused T cell to rally other cells to the immunity cause. This led to arthritis flare-ups in certain joints in mice. Additional inflammation was stopped when these T cells were removed. Researchers say that these T cells are not able to move between joints and they remain there, ready for activation again.
This approach was inspired by skin research. It is known that T cells possessing a memory form are found in the skin. This can lead to repeating patterns in skin conditions such as psoriasis. This can also happen when nickel is added to jewelry or wristwatches.
Nigrovic says that nickel may cause a reaction in people who wear nickel-containing watches as children.
They believe that other forms of autoimmune arthritis may work in the same manner, which could lead them to develop better treatments. Next, the team will confirm that this process occurs in humans and identify ways to target it.
Researchers believe that there may be other mechanisms that are contributing to RA memory retention. They suggest that T cells could be the cause in some cases, but not in others. Further research should be possible to examine this possibility.
There are millions of people suffering from rheumatoid arthritis around the globe. Any kind of relief or management of symptoms will be welcomed. Scientists are continually learning more about the disorder's mechanisms.
Nigrovic says that the treatment of rheumatoidarthritis must continue for life. "We can suppress the disease activity of many patients but there is no cure. Our findings could open up new therapeutic avenues, we believe.
Cell Reports published the research.
