Modified Waaler-Rose reaction employing sensitized human cells.

The Waaler-Rose test (Waaler, 1940; Rose, Ragan, Pearce, and Lipman, 1948) has established itself as a laboratory procedure of limited value in the diagnosis of rheumatoid arthritis. With a few exceptions the workers who have used it find it to be positive in under 75 per cent. of cases of that disease. It is rarely positive in other conditions, except disseminated lupus erythematosus and hepatitis. Its importance appears to lie in the fact that it is independent of non-specific plasma protein changes which give the raised erythrocyte sedimentation rate, increased plasma viscosity, positive serum colloidal gold reaction, positive formol-gel test, and abnormal electrophoretic pattern not only in rheumatoid arthritis but in many other chronic diseases. The test has a relative specificity which leads to the hope that with a fuller understanding of its underlying principles a "break through" may be established in the problem of aetiology. Many modifications have been introduced, but they have been mainly concerned with that part of the reaction represented by the patient's serum and the general conditions under which it reacts. An early refinement was the preliminary absorption of the serum by unsensitized sheep cells to remove natural anti-sheep haemolysin (Heller, Jacobson, and Kolodny, 1949). Attempts to isolate the active principle of the positive serum by fractionation have been numerous. Thus Svartz and Schlossmann (1953) claimed a high specificity for the cold-euglobulin fraction, and Robinson, Stulberg, and Kuyper (1954) and Ziff, Brown, Badin, and McEwen (1954), using the method of dialysis against solutions of low ionic strength, obtained the active principle in the euglobulin precipitate. Wager and Alameri (1953) also noted the low solubility of the factor. Hobson and Gorrill (1952) presented evidence that the agglutinating principle might be a thermostable complement fraction, and, by inference, suggested the ammoniainactivable fourth component C 4. Heller, Jacobson, Kolodny, and Schuman (1952) and Heller, Kolodny, Lepow, Jacobson, Rivera, and Marks (1955) found that various normal animal sera potentiated the reaction, and they devised a test using 5 per cent. (later 2 per cent.) sheep serum as diluent. Sheep serum was chosen as the most active of the animal species tested and not because the cells used were from that species. They made the important claim that under these conditions the strength of the reaction with normal sera was not dependent on the concentration of rabbit v. sheep amboceptor used to sensitize the cells as is the case with serum from rheumatoid cases. A four-fold or greater increase of titre in rheumatoid sera was noted with serum diluent as compared with saline diluent. Heller and others (1955) also employed Cohn's ethanol fractionation procedures in the analysis of the patient's serum effect and found that activity resided in Fraction III and probably in the betaliproprotein part of that fraction. Heller, Jacobson, Kolodny, and Kammerer (1954) made a further advance in technique by adsorbing Fraction Ii (y-globulin) from normal human serum on tanned sheep red cells and found that this could be substituted for the red cell-amboceptor system in a modified Rose test. An inhibitory factor in normal serum euglobulin absent from the serum of cases of rheumatoid arthritis, including those in which Waaler-Rose test is negative, has been demonstrated by Ziff and others (1954), who suggest that failure of the euglobulin to inhibit is a more sensitive indicator of the presence of agglutinating factor than the direct test. Heller and others (1954) also demonstrated an inhibitory effect following the addition of pooled Fraction II (y-globulin) to positively reacting rheumatoid sera. It has seemed to us that the test might be approached from the point of view of the "antigen". In its original form, the Rose test employed biological reagents from three species: sheep, rabbit,