How is Rheumatoid Arthritis Caused?

The cause of rheumatoid arthritis remains unknown. We do know that the body's autoimmune system attacks the synovial tissue in the joints but nobody knows what triggers this attack. It is felt that the cause may well lie in a complex combination of factors.

The University of Maryland Medical Center site states that-

" The actions of the helper T-cells are of special interest in rheumatoid arthritis. For some unknown reason, the T-cells become overactive in rheumatoid arthritis and mistake the body's own collagen as an antigen and trigger a series of immune responses to destroy the false enemy:

• TH-cells stimulate B-cells to produce antibodies. In this case, however, they appear to direct the B-cells to produce autoantibodies, which are directed against the body's own cells. Antibodies come in five types: IgM, IgG, IgA, IgD or IgE. The autoantibody in rheumatoid arthritis appears to be derived from IgG.
• H-cells also secrete or stimulate the production of powerful immune factors called cytokines. In small amounts, cytokines are indispensable for healing. If overproduced, however, they can cause serious damage, including inflammation and injury in the joints during the rheumatoid arthritis process. They may even be responsible for inflammation that occurs in parts of the body beyond the joints, including fever, shock, and even damage to organs, such as the liver."

The other feature of this phenomenon is that the body continues to attack the joints (albeit with some periods of remission) to the point of joint destruction which causes relentless pain and disability.

Some researchers believe that the attack is triggered by an infection or virus in people who already have a genetic susceptibility to RA. This susceptibility can also effect the severity of the disease. No single organism has been identified as the trigger.

RA itself is not inherited but the genes that lead to this suceptibility are.

It is felt that hormonal imbalances may also contribute to the onset of RA although we still don't understand how this process may occur. A study in 2004 found that an irregular menstrual cycle and an earlier age for the onset of menarche increased the risk of RA in women. A study of 176 women in 1976 found that oral contraception use of longer than five years had a protective effect against severe RA although such use did not have any effect on the incidence of RA.

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