Rheumatoid arthritis is an autoimmune chronic inflammatory condition that could affect 41 in 100,000 people yearly. The exact cause of this costly and debilitating disease is not yet known although multiple risk factors have been identified. Notable risk factors include being female which increases the likelihood of developing the disease by three-fold and family history.

Despite numerous milestones in understanding the condition, effective preventive interventions are yet to be developed. However, researchers have discovered a possible way of preventing the condition through an unusual mechanism found in the human mouth.

A study published in the journal Science Translational Medicine states that the trigger for the autoimmune reaction seen in rheumatoid arthritis may actually come from bacteria found in patients with a chronic gum infection. Aggregatibacter actinomycetemcomitans, the bacteria in question has been prevalent in those patients suffering from rheumatoid arthritis. This link points out a possibility that the bacteria are the culprit in causing the cascade of inflammatory substances seen in this type of arthritis.

The relationship between gum disease and rheumatoid arthritis is surprisingly not new. As early as the 1900s, doctors have noticed a clinical association in the occurrence of both diseases. Despite this old relationship, the link between the two has never been clearly described up till now.

The process that researchers believe causes the body to attack itself is called hypercitrullination. Normally, in this process, the amino acid arginine is converted into citrulline which in normal levels does not trigger inflammation. In the cause of rheumatoid arthritis, the process is exaggerated and the body levels of citrulline become too high. Researchers have found that the presence of A. actinomycetemcomitans contributes to elevated levels of citrulline and consequently places the body in a hyperinflammatory state.

Although this angle sparks a lot of excitement in the research for a cure for rheumatoid arthritis, researchers are quick to point out that almost 50 percent of those with rheumatoid arthritis do not have an evidence of A. actinomycetemcomitans infection in their system. This could mean that the presence of such bacteria is not an absolute cause but rather one of the multitudes of risk factors leading to RA.

With the search of other bacteria that could trigger inflammation, the researchers are hopeful that by targeting these bacterial triggers, a new treatment for RA is on its way.

Rheumatoid Arthritis (RA) CDC

https://www.cdc.gov/arthritis/basics/rheumatoid.htm

Aggregatibacter actinomycetemcomitans–induced hypercitrullination links periodontal infection to autoimmunity in rheumatoid arthritis

http://stm.sciencemag.org/content/8/369/369ra176