Severe hemolytic transfusion reaction due to anti-A1 following allogeneic stem cell transplantation with minor ABO incompatibility

Abstract

Blood components should be compatible both with the recipient and the donor in the ABO incompatible allogeneic stem cell transplantation setting. A patient with blood type A2 received peripheral blood stem cells from a blood type O donor. The patient was in critical condition due to treatment-related toxicity. He had acquired anti-A1 that was unfortunately overlooked. Following transfusion of A1 red blood cells in error, he developed a severe hemolytic transfusion reaction. Anti-A1 is rarely clinically significant. We discuss the role of passenger lymphocytes in development of the anti-A1, and stress the importance of investigating unusual/atypical reactions in blood typing.