A patient with aplastic anemia, typed as blood group B and CCDee, was treated with antilymphocyte globulin (ALG) intravenously, 40 mg/kg/day, for 4 days. She developed a positive direct antiglobulin test three days after the beginning of administration. Anti-C activity was detected in the administrated lot of ALG as well as the eluate from the patient's sensitized erythrocytes, when tested with C positive indicator red cells. In addition, laboratory findings provided the evidence for slight hemolysis. Careful investigation of ALG as a source of blood group specific antibody should be conducted.
