ABH incompatible bone marrow transplantation: removal of erythrocytes by starch sedimentation.

Nineteen patients with acute leukaemia underwent bone marrow transplantation despite major ABH incompatibility between donor and recipient. The marrow inoculum was prepared prior to infusion by admixture with hydroxyethyl starch to sediment the incompatible erythrocytes, which were then discarded. The infusion was well tolerated with two patients developing transient haemoglobinuria, seven patients developing low grade fever and 10 experiencing no reaction. Durable haematopoietic engraftment was achieved in the 18 evaluable patients and was not influenced by pre-transplant isohaemagglutinin titres. No difference in time to engraftment, incidence of GVHD or in overall survival was found, compared to ABH compatible transplants. Therefore, the presence of incompatibility did not appear to influence transplant outcome adversely. The technique described is a rapid and safe method for overcoming the ABH barrier in marrow transplantation.