A Relationship of Direct Coombs Test Pattern to Autoantibody Specificity in Acquired Hemolytic Anemia

Summary

Of 31 cases of acquired hemolytic, anemia with “warm” γG autoantibodies, 17 exhibited positive direct antiglobulin reactions only with anti-γG globulin (Group 1) while 14 gave positive reactions with both anti-γG globulin and anti-complement serum (Group 2). As a preliminary test of Rh-related specificity, autoantibodies eluted from the RBC of patients in both groups were studied for their reactivity with Rh_null RBC. Twelve of 13 eluates showing negative or feeble reactions with Rh_null RBC were from patients in Group 1. Conversely, 13 of 18 eluates which gave reactions of equal intensity against Rh_null RBC and “normal” RBC were from patients in Group 2. The correlation of these apparent differences in antibody specificity with differences in the potential of γG autoantibodies for in vivo complement fixation has been discussed.