Why is rheumatoid arthritis (RA) sometimes called an autoimmune disease?
Autoimmune diseases are characterized by an immune system attack on healthy tissues. In RA, white blood cells travel to the synovium (the membranes that surround joints) and cause inflammation, or synovitis. The ensuing warmth, redness, swelling and pain are typical symptoms of rheumatoid arthritis, which usually affects the wrist joints and the finger joints closest to the hand.
