Anti-antibody and other antiglobulin specificities in nonrheumatoid and rheumatoid effusion fluids and matched sera.

Abstract

Abstract When 70 effusions and their matched sera were assayed in 4 rheumatoid factor tests, 1458 nonrheumatoid source materials showed definite agglutination activity. These nonrheumatoid agglutinators were compared for agglutination specificity with 12 classic rheumatoid-source agglutinators which gave typical rheumatoid factor test results. Both rheumatoid and nonrheumatoid agglutinators were commonly found in the 19S fraction. However, the nonrheumatoid agglutinators were detected mainly in systems where the γ-globulin had reacted as an antibody, such as the human anti-Rh-sensitized test. The positive tests were not blocked by the addition of excess pooled γ-globulin to the test media as were the rheumatoid-factor agglutinators. Furthermore, several nonrheumatoid materials were shown to contain a 7S globulin reactive with pepsin-digested anti-CD globulin coated on red cells. The occurrence of such pepsin agglutinators in rheumatoid source material was also seen. Therefore, there are shown to be several antiglobulin agglutination specificities in effusions and sera. Care should be taken in specificity identification to not infer that all agglutinators reactive in rheumatoid-factor tests are classic rheumatoid factors. It is suggested that the rheumatoid and the nonrheumatoid fluids can be distinguished by more extensive serologic testing of the antiglobulin activities.