[Donor cell leukemia (DCL): A prospective study of its identification and treatment].

Donor-derived malignancies after allogeneic hematopoietic stem cell transplantation and after solid organ transplantation are considered as rare diseases. We have prospectively searched for donor cell leukemia in a 12-year period, in a single institution, in a group of 106 consecutive patients allografted because of leukemia. We have identified seven cases of donor cell leukemia; six were allografted because of relapsed acute lymphoblastic leukemia and one because of paroxysmal nocturnal hemoglobinuria/aplastic anemia. These figures suggest that the real incidence of donor cell leukemia has been underestimated. The six patients with lymphoblastic donor cell leukemia were treated prospectively with a pediatric-inspired combined chemotherapy schedule designed for de novo acute leukemia. A complete response was obtained in three out of six patients with lymphoblastic donor cell leukemia. It is possible to obtain favorable responses in donor cell leukemia patients employing combined chemotherapy. The long-term donor cell leukemia survivors remain as full chimeras and have not needed a second transplant.