rheumatoid arthritis - 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 jointvirus - (virology) ultramicroscopic infectious agent that replicates itself only within cells of living hosts; many are pathogenic; a piece of nucleic acid (DNA or RNA) wrapped in a thin coat of protein arthritis - inflammation of a joint or joints autoimmune disease, autoimmune disorder - any of a large group of diseases characterized by abnormal functioning of the immune system that causes your immune system to produce antibodies against your own tissues psoriatic arthritis - a form of rheumatoid arthritis usually affecting fingers and toes and associated with psoriasis |