Source : WordNet®

rheumatoid arthritis
     n : a chronic autoimmune disease with inflammation of the joints
         and marked deformities; something (possibly a virus)
         triggers an attack on the synovium by the immune system,
         which releases cytokines that stimulate an inflammatory
         reaction that can lead to the destruction of all
         components of the joint [syn: {atrophic arthritis}, {rheumatism}]