Researchers suspect that oral bacteria could be involved in rheumatoid arthritis (RA). In patients with RA, hypercitrullination, an abnormal buildup of citrullinated proteins, triggers the immune system to generate autoantibodies that attack these modified self-proteins, inducing joint-destroying inflammation. Citrullination is a normal, function altering process that changes the structure of proteins. In patients with RA, hypercitrullination, an abnormal buildup of citrullinated proteins, triggers the immune system to generate autoantibodies that attack these modified self-proteins, inducing joint-destroying inflammation. Andrade Konig, et al. found a mouth bug, Aggregatibacter actinomycetenocomitans, can cause these runaway protein changes, and drive RA-specific autoantibody production, key steps in the path to RA. Nineteen of the modified proteins induced by the toxin are known autoantigens targeted by autoantibodies in RA. There are data suggesting that treating periodontitis can decrease RA disease severity, and it was noted that several large prospective trials are currently under way to further investigate this possibility. Cigarette smoking is also strongly associated with RA, and bacteria with pore-forming toxins in the lungs of smokers could explain the link.
Abbasi J. To Prevent Rheumatoid Arthritis, Look Past the Joints to the Gums. JAMA. Published online March 08, 2017. doi:10.1001/jama.2017.0764.