6: Post-transplantation high-dose cyclophosphamide (Cy) is effective single agent GVHD prophylaxis that permits prompt immune reconstitution after myeloablative HLA matched related and unrelated bone marrow transplantation (BMT)

Prolonged pharmacologic immunosuppression is a major obstacle to early immunologic recovery after allogeneic BMT. Based on our results in animal models, we studied whether high dose Cy alone after HLA-matched related or unrelated BMT is effective prophylaxis against severe acute GVHD while permitting effective reconstitution of lymphocytes, including regulatory T cells (Tregs). Forty-six consecutive patients (median age 41, range 1-64) with advanced hematologic malignancies received HLA-matched related (n=28) or unrelated (n=18) bone marrow after conditioning with busulfan on days -7 to -3 and Cy (50 mg/kg/day) on days -2 and -1, +3, and +4.