THEAGGLUTINATING FACTOR FOR SENSITIZED SHEEP ERYTHROCYTES IN SERUM AND JOINT FLUID FROM RHEUMATOID ARTHRITIS PATIENTS BY

for Internal Medicine of a special method for the sheep-cell agglutination test based on experiments made by the authors (Svartz and Schlossmann, 1949). A similar account was presented to the Seventh International Congress on Rheumatic Diseases, New York, 1949. First we must emphasize the fact that all human sera contain heterophil haemagglutinins which agglutinate normal (unsensitized) red sheep cells. In certain diseases such agglutinins occur in a higher titre than in the serum of healthy persons. These heterophil agglutinins can always be absorbed by normal sheep cells. In rheumatoid arthritis, and in isolated cases of other diseases, there exists in the blood another type of agglutinating factor, not absorbable by normal sheep cells and unable to agglutinate them. This factor only agglutinates sheep cells which have been sensitized with a small amount of rabbit anti-sheelp-cell serum (amboceptor). The agglutination with normal sheep cells is inhibited by extract from the kidneys of guinea-pigs. This is not the case with the agglutination with sensitized sheep cells