Anti-A1 in the plasma of platelet concentrates causing a hemolytic reaction

A patient with acute leukemia who typed as AintB received 10 packs of platelets of group 0. Subsequent transfusion of A1B blood resulted in a hemolytic transfusion reaction. Anti-A1 was detected in the serum and on the red blood cells of a post-transfusion sample. This anti-A1 reacted with the transfused A1B red blood cells and other A1 cells, but not with the patient's pretransfusion red blood cells. The plasma of the transfused platelet concentrates had a high titer of immune anti-A.