Rheumatoid Factor IgM ELISA
The IMMUNOLAB Rheumatoid Factor (RF) IgM ELISA Test Kit has been designed for the the detection and the quantitative determination of RF in serum and plasma. Further applications in other body fluids are possible and can be requested from the Technical Service of IMMUNOLAB.
Rheumatoid arthritis (RA) is a chronic inflammatory disease of unknown etiology. Rheumatoid arthritis is a systemic disease characterized by chronic proliferation and inflammation of joint cartilage and supporting structures. RA is mainly defined by clinical criteria, in which systematic pathogenetic studies have been hampered by doubts about the presence of common pathogenetic mechanisms and the relative lack of unique laboratory findings. IgG rheumatoid factor has been reported to be present in sera of patients with rheumatoid arthritis both with and without IgM rheumatoid factor activity. Rheumatoid factors are IgA, IgG and IgM immunoglobulins with antibody activity directed against antigenic sites on the Fc portion of IgG molecules. Because of its pentavalent structure and ability to cross-link immunoglobulin G antigen, IgM Rheumatoid Factor is the main class identified by clinically available diagnostic assays for Rheumatoid Factor detection. Rheumatoid factors may exist as the mu, gamma, alpha, and epsilon isotypes. Rheumatoid factors are found in 1 to 4 % of the general population. They are present in 75% of adult patients with the highest incidence of rheumatoid factors occurring in persons over 65 years of age and nearly all patients with Felty and Sjogren syndrome. The clinical correlation of an elevated rheumatoid factor should be interpreted cautiously. Increased titers may accompany a variety of acute immune responses, particularly viral infections and a number of other diseases (e.g., infectious mononucleosis, tuberculosis, leprosy, various parasitic diseases, liver disease, sarcoidosis, and lymphoproliferative syndromes). The earliest tests and those still most widely used rely on the agglutinating properties of the IgM class of rheumatoid factors. Sensitized sheep red blood cell (Waaler-Rose) and latex agglutination tests have been developed and routinely employed. These assays are most sensitive for the detection of Rheumatoid factor that is of the IgM isotype because of its multivalent structure. These tests provide a dilution which is difficult to standardize and have laborious processing and poor reproducibility. In contrast to these assays modern ELISA tests are characterized by a higher sensitivity and by the possibility to differentiate between IgA, IgG and IgM Rheumatoid Factors.
The IMMUNOLAB RF IgM test kit is based on the principle of the enzyme immunoassay (EIA). Goat IgG is bound on the surface of the microtiter strips. Diluted patient serum, ready-to-use standards and controls are pipetted into the wells of the microtiter plate. A binding between the RF IgM of the serum and the immobilized goat IgG takes place. After a one hour incubation at room temperature, the plate is rinsed with diluted wash solution, in order to remove unbound material. Then ready-to-use anti-human-IgM peroxidase conjugate is added and incubated for 30 minutes. After a further washing step, the substrate (TMB) solution is pipetted and incubated for 20 minutes, inducing the development of a blue dye in the wells. The color development is terminated by the addition of a stop solution, which changes the color from blue to yellow. The resulting dye is measured spectrophotometrically at the wavelength of 450 nm. The concentration of the RF IgM is directly proportional to the intensity of the color.
- Adebajo AO; Wright JK; Cawston TE; Hazleman BL: Rheumatoid factor quantitation: a comparison of ELISA and nephelometric methods. Med Lab Sci 1991 Jan; 48(1):47-51.
- Banchuin N; Janyapoon K; Sarntivijai S; Parivisutt L: Re-evaluation of ELISA and latex agglutination test for rheumatoid factor detection in the diagnosis of rheumatoid arthritis. Asian Pac J Allergy Immunol 1992 Jun; 10(1):47-54.
- Barka NE; Agopian MS; Peter JB: False-positive IgM antibodies to Borrelia burgdorferi in indirect ELISA as a result of IgM rheumatoid factor. J Infect Dis 1990 Jun; 161(6):1312.
- Dabadghao S; Misra R; Naveed M; Aggarwal A: IgM rheumatoid factor estimation by ELISA in seronegative rheumatoid arthritis. Rheumatol Int 1996; 15(5):189-93.
- Espersen GT; Ernst E; Vestergaard M; Grunnet N: ELISA estimations of rheumatoid factor IgM, IgA, and IgG in sera from RA patients with high disease activity. Scand J Rheumatol Suppl 1988; 75:40-5.
- Gargiulo AV Jr; Toto PD; Robinson JA; Gargiulo AW: Latex slide agglutination vs. ELISA system. Rheumatoid factor detection. J Periodontal Res 1985 Jan; 20(1):31-4.
- Gioud-Paquet M; Auvinet M; Raffin T; Girard P; Bouvier M; Lejeune E; Monier JC: IgM rheumatoid factor (RF), IgA RF, IgE RF, and IgG RF detected by ELISA in rheumatoid arthritis. Ann Rheum Dis 1987 Jan; 46(1):65-71.
- Hoier-Madsen M; Grunnet N; Wiik A: A Danish inter-laboratory study of IgM rheumatoid factor (RF) determined by enzyme-linked immunosorbent assay (ELISA). Scand J Rheumatol Suppl 1988; 75:50-3.
- Jonsson T; Arnason JA; Valdimarsson H: Enzyme-linked immunosorbent assay (ELISA) screening test for detection of rheumatoid factor. Rheumatol Int 1986; 6(5):199-204.
- Karsh J; Halbert SP; Anken M; Klima E; Steinberg AD: Anti-DNA, anti-deoxyribonucleoprotein and rheumatoid factor measured by ELISA in patients with systemic lupus erythematosus, Sjogren’s syndrome and rheumatoid arthritis. Int Arch Allergy Appl Immunol 1982; 68(1):60-9.
- Lucic N; Mahic Zikic A; Lipa I; Seremet M: Comparison of the immunoenzyme test (ELISA) with other methods in the detection of rheumatoid factor. Reumatizam 1989; 36(1-6):24-30.