Abstract
The establishment of a hematopoietic graft of stem cells from a donor with chronic myelogenous leukemia in a patient with acute leukemia took place in the face of ABO red cell group incompatibility. The donor was group A and the recipient who was group O gradually increased his red cell mass to become 80 per cent group A.
There was both active and passive immunity to A present at the time of induction of the graft. The graft flourished despite persistent anti-A agglutinins and an immune response in the B agglutinin and hemolysin system.
Failure of the graft coincided with a fall in antibody levels and was followed by a second immune response which included marked elevation of 7S gamma globulin levels. Red cell incompatibility was not a barrier to this graft and failure of the graft was probably due to other immune mechanisms.
