Anti‐Wrb, and Other Autoantibodies Responsible for Positive Direct Antiglobulin Tests in 150 Individuals

Abstract

Eluates from the red blood cells (and sera whenver free autoantibody was present) of 150 individuals with positive direct antiglobulin tests were studied for antibody specificity. Of 87 patients with AIHA [autoimmune hemolytic anemia], 64 had autoantibodies reacting with all red cell samples including Rhnull. Of these 64 anti-dl autoantibodies, 2 were, and 32 contained, auto-anti-Wrb. Of 33 patients being treated with .alpha.-methyldopa who developed positive direct antiglobulin tests, 23 had anti-dl autoantibodies 4 of which contained auto-anti-Wrb. Of 30 hematologically normal donors with positive direct antiglobulin tests, 23 had anti-dl autoantibodies, 2 of which were, and 6 of which contained, auto-anti-Wrb. The full specificities of autoantibodies, other than anti-Wrb and anti-dl, in the 150 patients are described, as are the natures of the protein red cell coatings that caused the positive direct antiglobulin tests. The presence of free serum autoantibody as a correlate of the 3 clincal conditions is reported. Several observations on auto-anti-Wrb are documented. The antibody can cause gross red cell destruction in vivo but can be benign on other occasions; it occurs with approximately the same frequency in AIHA patients and normal donors with positive direct antiglobulin tests, but in fewer patients with .alpha.-methyldopa induced positive direct antiglobulin tests; it does not activate complement in vivo; and it may eventually provide a clue to the etiology of AIHA.