Quantitative Considerations of the Rheumatoid Factor

Abstract

Precipitation of the rheumatoid agglutinating factor with purified preparations of gamma globulin has been studied. The values and limitations of present precipitin techniques for accurately measuring the factor have been defined. Absorption with rabbit immune precipitates selectively removed that portion of the rheumatoid factor responsible for agglutination of sheep cells coated with rabbit antibody, with minimal reduction of agglutination titer for cells coated with human γ-globulin. Quantitative precipitation technics, however, demonstrate very significant reduction of material precipitable by human Fraction II after such absorption. The sharp specificity of the rheumatoid factor towards certain systems is emphasized.