Chronic myelogenous leukemia (CML) is a uniformly lethal malignant disorder of the hematopoietic stem cell. Although CML cannot be cured with conventional therapy, recent results suggest that therapy with marrow transplantation may prolong survival and, in some cases, provide curative therapy. Approximately 30% of otherwise eligible marrow transplant candidates have an HLA matched or one antigen mismatched related donor. Related donor marrow transplantation therapy for patients in the chronic phase of CML results in 45-70% long-term, disease-free survival. Younger recipient age, transplant in chronic rather than advanced phase and transplant within one year of diagnosis provide a better outcome. Graft versus host disease (GVHD), pneumonia and systemic infections are commonly encountered complications. T-lymphocyte depletion of donor marrow reduces the incidences of acute and chronic graft versus host disease but is associated with a higher relapse rate and lower overall incidence of disease-free survival than use of non-T-depleted marrow. The use of HLA matched or one antigen mismatched unrelated donors allow successful marrow transplantation in approximately 30% of CML cases where a suitably matched related donor is not available. Unrelated donor marrow transplantation can provide stable engraftment in the majority of recipients and lead to leukemia-free survival in many cases. The beneficial effects of unrelated donor marrow transplantation are particularly apparent in young, chronic phase recipients and when performed using donor/recipient pairs identical at the HLA A, B and DR loci. A higher incidence of graft failure and GVHD than observed in sibling marrow transplant as well as prolonged convalescence in some cases can be anticipated. Advances in testing of the major histocompatibility loci at the molecular level may expedite location of better matched donors. The rapidly expanding international network of registries will make unrelated donor marrow transplantation therapy an option for a large number of patients with CML.
- Marrow transplant
- Unrelated donor