Evaluation of a New Preserved Latex Antigen for the Sero-diagnosis of Rheumatoid Arthritis.

Serological procedures useful for the detection of rheumatoid factors, utilizing polystyrene latex particles, have become well established and show a reasonably good degree of specificity and sensitivity (Mayne and Mathieson, 1961; Plotz and Singer, 1956; Vaughan, 1959). The use of these tests has been reviewed by Singer (1961) and Waller, Decker, Toone, and Irby (1961). The tests have also been found of value in studying patients with nonrheumatic diseases (Atwater and Jacox, 1963; Caplan, 1963; Dresner and Trombly, 1959; Howell, Malcolm, and Pike, 1960). Many modifications of the original Singer and Plotz Fraction II Latex Particle (F-IT L.P.) method (Singer and Plotz, 1956) have been reported, both slide and test tube (Bird and Burr, 1962; Rheins, McCoy, Buehler, and Burrell, 1957a; Singer and Plotz, 1958a, b). The F-TI L.P. procedure uses polystyrene latex particles (Dow, 0 81 ,t in diameter) sensitized with human gamma globulin (Fraction TI) in an alkaline buffer. Rheins, McCoy, Burrell, and Buehler (1957b) showed that gamma globulin from seven animal species, including bovine, could be used in place of human gamma globulin. Burby and Behr (1958) found that Dow 0 81 , particles sensitized with bovine globulin were as satisfactory for this test as were those sensitized with human gamma globulin, and the same authors (1959) also reported that a new polystyrene latex particle manufactured in Great Britain gave results equivalent to those obtained with the Dow particles, if used in a different dilution. Payne (1961) described a new procedure using the British latex particles sensitized with bovine gamma globulin in an alkaline buffer. He claimed that his procedure showed good agreement with the sensitized sheep cell agglutination test (Jacobson, Kammerer, Wolf, Epstein, and Heller, 1956) and F-TI L.P. tests, and was technically simpler. Recently, we have prepared a new preserved concentrated antigen for the detection of rheumatoid factor in serum. This antigent is prepared from polystyrene latex particles, similar to those used by Payne (1961), sensitized with bovine gamma globulin. The advantages claimed for this antigen are that it is economical, stable, and simple to use, and an evaluation was therefore conducted to compare this material with other widely used latex procedures in the sero-diagnosis of rheumatoid factor.