Hematologic and cytogenetic remission of 5q-refractory anemia after syngeneic bone marrow transplantation.

Refractory macrocytic anemia with hypolobulated megakaryocytic nuclei and partial deletion of the long arm of chromosome 5 has been termed the 5q- syndrome. Although long survival has been reported in a few cases of 5q- refractory anemia, accumulating evidence suggests that this syndrome is a preleukemic state with risk of transformation to acute nonlymphocytic leukemia as well as complications of bone marrow failure. This report describes the first apparently successful therapy for this disorder in a young man who originally presented with a clinical picture consistent with pure red cell aplasia and normal marrow chromosomes but with hypolobulated megakaryocytic nuclei. He was treated with vitamins, androgens, and sequential trials of immunosuppressive therapy, all without response. Two years after diagnosis, repeated marrow cytogenetic studies showed a 5q- abnormality in 70 percent and later in 100 percent of marrow metaphases. Because of transfusion-induced hemosiderosis and the availability of a cytogenetically normal monozygotic twin, bone marrow transplantation was undertaken. In light of the clonal (and suspected preleukemic) nature of the 5q- syndrome, the patient's marrow was ablated with a busulfan plus cyclophosphamide regimen used for patients with nonlymphocytic leukemia. Sustained engraftment of cytogenetically normal marrow ensued. Two years after transplantation, and following six months of regular phlebotomy, the patient was hematologically normal with a normal serum ferritin level.