Treatment of chronic myelogenous leukemia with bone marrow transplantation.

BMT is the only curative therapy for CML, a uniformly lethal malignant disorder of the hematopoietic stem cell. Younger patient age and transplant in CP are associated with better outcome. Transplant within 1 year of diagnosis may provide a greater chance of survival than transplant at a longer interval from diagnosis. T-cell depletion of donor BM significantly reduces the incidence of acute and chronic GVHD, but is associated with an increased risk of graft failure and a marked increase in rate of relapse. Early results suggest that HLA-matched or partially HLA-mismatched unrelated donors may be used successfully in cases in which a suitably matched related donor is not available. Autologous transplantation of BM or PB stem cells can result in successful engraftment and possibly prolonged survival in some patients with CML. Following allogeneic BMT, some patients relapse cytogenetically without progressing to hematologic relapse. The use of PCR methodology to amplify bcr-abl transcripts has revealed persistence of the malignant clone in a substantial number of patients who are in hematologic and cytogenetic remission. The clinical significance and biologic mechanism(s) of this form of molecular relapse remain to be defined.