Rapid engraftment after allogeneic ABO-incompatible peripheral blood progenitor cell transplantation complicated by severe hemolysis

A patient with CML in accelerated phase received G-CSF-mobilized PBPC from an unrelated HLA genotypically matched donor. The blood groups of the patient and donor were bidirectionally incompatible. Hematologic recovery was rapid with >500 PMN/μ l on day +9. Starting on day +5 bilirubin levels increased from 1.3 mg/dl up to a maximum of 18 mg/dl on day +14. Clinical signs and laboratory tests supported major hemolysis. Blood typing on day +16 revealed early blood-group change, consistent with donor-derived antibodies produced by passenger-lymphocytes which may have mediated severe hemolysis. The early onset and strong intensity of the hyperbilirubinemia could be a specific feature of ABO-incompatible allogeneic PBPC transplantation which would be difficult to differentiate from GVHD or VOD.