[Administration of haptoglobin in ABO incompatible bone marrow transplantation]

Haptoglobin was administered i.v. in 2 cases of ABO incompatible bone marrow transplantation for the prevention of hemoglobinuria due to acute hemolysis. The first case was a 25-year-old woman with severe aplastic anemia. The transplantation was both major and minor mismatch, where the donor was type A and the recipient was type B. The second case was a 31-year-old man with chronic phase of chronic myelogenous leukemia. The transplantation was major mismatch, where the donor was type B and the recipient was type O. After the administrations of haptoglobin 8,000 units we transfused bone marrow infusates from which incompatible erythrocytes were removed. Though prominent hemoglobinemia was observed in both cases, the serum haptoglobin values were not saturated and hemoglobinuria was not detectable. Haptoglobin appears to be useful for the prevention of acute renal failure associated with acute hemolysis in ABO incompatible bone marrow transplantation. Intravenous haptoglobin supplement therapy makes transplantation safer and may contribute to improve the recovery rate of total nucleated bone marrow cells after the erythrocyte depletion without worrying much about their contamination.