Musculoskeletal Imaging

Rheumatoid factor

an autoantibody present in many persons with rheumatic disease, especially rheumatoid arthritis and ankylosing spondylitis. Rheumatoid factor is also present in patients with calcium pyrophosphate dihydrate crystal deposition disease, dermatomyositis, polymyositis, scleroderma, haemochromatosis, primary biliary cirrhosis and relapsing polychondritis. Some rheumatic diseases resembling rheumatoid arthritis but in which rheumatoid factor is lacking are termed seronegative spondyloarthropathies; examples are ankylosing spondylitis, psoriatic arthritis and Reiters syndrome.

Rheumatoid factor reacts with the Fc portion of immunoglobulin G. The formation of immune complexes in vivo may be related to the pathogenesis of rheumatoid disease, but exact mechanisms are unknown.

Numerous tests have been developed for the detection of rheumatoid factor, many of them based on human or rabbit IgG antigen.

DR