Rheumatoid Factors (RFs) were described as Immunoglobulins (IgGs) in rheumatoid arthritis as detected by agglutination of rabbit IgG coated erythrocytes. It was later demonstrated that RFs were IgM molecules reactive with the Fc-portion of the IgG from various species. In addition to the IgM RF, subsequent studies have identified RFs of other IgG subtypes (IgG, IgA, and IgE) in serum of patients with rheumatoid arthritis, and certain other chronic diseases. Most commercial assays measure predominantly IgM RFs. It has been observed that measurement of IgG RF may be a better indicator of rheumatoid arthritis than IgM RF. IgA RF and IgE RF have been implicated in articular disease process in rheumatoid arthritis and rheumatoid vasculitis, respectively. RFs, produced by cells within the joint space, are found in joint fluids as well. RF titer, particularly IgG RF correlate with the intensity of synovitis.
RFs can be found in serum samples from a variety of autoimmune diseases including rheumatoid arthritis, Systemic lupus erythematous, Sjogren’s syndrome, mixed connective tissue disease, mixed essential cryoglobulinemia, scleroderma, subacute bacterial endocarditis, leprosy, pulmonary fibrosis, and pulmonary silicosis. RFs may also be found in patients with syphilis, viral infections, chronic liver diseases, sarcoidosis, leprosy, neoplasms, and a variety of other chronic conditions.
Rheumatoid Factor (RF), BioAssay™ ELISA Kit is a sandwich ELISA for detecting and qualifying RF (IgG, IgM and/or IgA) activity in mouse serum and plasma.
Storage and Stability:Store all components at 4°C. Stable for 6 months after receipt. For maximum recovery of product, centrifuge the original vial prior to removing the cap.
