02040nas a2200349   4500000000100000008004100001260001300042653001000055653001200065653002500077653002600102653003700128653001300165653002700178653001100205653002000216653003200236653002100268653002500289653001200314653002200326653001600348653001000364653001300374653001900387100001700406245010100423300001100524490000700535520113400542022001401676       1983                            d  c1983 May10aAging10aAnimals10aAntibody Specificity10aArthritis, Rheumatoid10aEndocarditis, Subacute Bacterial10aEpitopes10aHemagglutination Tests10aHumans10aImmunochemistry10aImmunoglobulin Fc Fragments10aImmunoglobulin M10aLatex Fixation Tests10aleprosy10aRheumatoid Factor10aSarcoidosis10aSheep10aSyphilis10aVirus Diseases1 aWilliams R C00aSymposium on the immunodiagnosis of rheumatic and related diseases, Part II. Rheumatoid factors.  a386-910 v143 a<p>Human rheumatoid factors are antibodies of IgG, IgA, or IgM class that show reactions with antigenic determinants present on other immunoglobulin molecules. The most commonly measured rheumatoid factor relates to the 19S IgM type, which reacts by agglutination of latex particles coated with 7S IgG and is often measured in the standard latex fixation test. Approximately 65 to 70 per cent of patients with rheumatoid arthritis show positive serologic tests for rheumatoid factor; however, a number of other chronic disease conditions are also associated with positive rheumatoid factor reactions, including infective endocarditis, sarcoidosis, leprosy, and other hyperglobulinemic conditions. Although extensive serologic and immunochemical studies have identified a number of specific antigenic structural sites on immunoglobulin molecules that react with rheumatoid factors, recent studies have shown that a certain proportion of such antibodies may show cross-reactivity with DNA-histone complexes as well. It is still not entirely clear how rheumatoid factors fit into the pathogenesis of rheumatoid arthritis itself.</p>  a0046-8177