Cellular immunity in the joints of patients with rheumatoid arthritis and other forms of chronic synovitis.

Rheumatoid arthritis (RA), although a systemic illness, is primarily a synovial disease. Morphologic and functional studies of immune cells within the synovium strongly suggest that disordered cellular immunity is key to the pathogenesis of RA. This article describes in detail the various cells found within the rheumatoid joint and compares them with those found in nonrheumatoid synovitis and in normal peripheral blood.