What is the most common cause of rheumatoid arthritis?

The exact cause of RA is at present not known Rheumatoid arthritis (RA) is an autoimmune disorder. That is a disorder where the immune system of the body mistakenly destroys the bodies own tissue. In the case of RA, joints and other tissues of the body are attacked by the immune system. Most commonly the immune system attacks synovia, the fluid around joints, causing swelling and discomfort

We are unsure of the exact mechanisms that brings about RA. However researchers feel these factors are involved. Chemicals called cytokines are used by the immune system cells to communicate. It is thought that people with RA have too much of certain types of cytokines, including interleukin (IL) and tumour necrosis factor alpha (TNF-α), which may be sending the messages that cause the joints to be attacked. There is a greater risk of having RA if there is a member of the family with the disease or if you are female. Some family's are genetically predisposed to RA making them more prone to the disease. Biological factors such as hormone changes, or factors such as an infection, are believed to trigger the immune system to attack the joints in people prone to RA.