Transplant management
Conditioning regimen
The biological aspects of allogeneic HSCT in TM are different from those for hematologic malignancies. There is no necessity to eradicate a malignant clone and the graft-versus-tumor effect is not required.11 Moreover, TM patients have not received previous chemotherapy and their immunological system is not impaired. TM patients have a hypercellular and expanded marrow.46 Additionally, in adolescent or adults undergoing HSCT, sensitization to red blood cell antigens may have occurred, possibly together with development of anti-HLA antibodies.47 In these circumstances, the ideal conditioning regimen should be capable of eradicating the diseased marrow and be sufficiently immunosuppressive to permit a sustained engraftment. For many years, the preferred regimen included oral busulfan (Bu) at 14 mg/kg and cyclophos- phamide (Cy) at 120-200 mg/kg.