Rheumatoid factor

Not to be confused with Rhesus factor.

Rheumatoid factor (RF) is the autoantibody that was first found in rheumatoid arthritis. It is defined as an antibody against the Fc portion of IgG and different RFs can recognize different parts of the IgG-Fc.[1] RF and IgG join to form immune complexes that contribute to the disease process such as chronic inflammation and joint destruction at the synovium and cartilage.[2]

Rheumatoid factor can also be a cryoglobulin (antibody that precipitates on cooling of a blood sample); it can be either type 2 (monoclonal IgM to polyclonal IgG) or type 3 (polyclonal IgM to polyclonal IgG) cryoglobulin.

Although predominantly encountered as IgM, rheumatoid factor can be of any isotype of immunoglobulins; i.e., IgA, IgG, IgM,[3] IgE,[4] IgD.[5]

  1. ^ Falkenburg, W.J.J. (November 2015). "IgG Subclass Specificity Discriminates Restricted IgM Rheumatoid Factor Responses From More Mature Anti–Citrullinated Protein Antibody–Associated or Isotype-Switched IgA Responses". Arthritis & Rheumatology. 67 (12): 3124–3134. doi:10.1002/art.39299. PMID 26246004.
  2. ^ Edkins A, Cushley W (2012). "The Jekyll and Hyde nature of antibodies". Biological Sciences Review. 25 (2): 4.
  3. ^ Hermann, E; Vogt, P; Müller, W (1986). "Rheumatoid factors of immunoglobulin classes IgA, IgG and IgM: Methods of determination and clinical value". Schweizerische Medizinische Wochenschrift. 116 (38): 1290–7. PMID 3775335.
  4. ^ Herrmann, D; Jäger, L; Hein, G; Henzgen, M; Schlenvoigt, G (1991). "IgE rheumatoid factor. Occurrence and diagnostic importance in comparison with IgM rheumatoid factor and circulating immune complexes". Journal of Investigational Allergology & Clinical Immunology. 1 (5): 302–7. PMID 1669588.
  5. ^ Banchuin, N; Janyapoon, K; Sarntivijai, S; Parivisutt, L (1992). "Re-evaluation of ELISA and latex agglutination test for rheumatoid factor detection in the diagnosis of rheumatoid arthritis". Asian Pacific Journal of Allergy and Immunology. 10 (1): 47–54. PMID 1418183.