Infusion of HLA-mismatched peripheral blood stem cells improves the outcome of chemotherapy for acute myeloid leukemia in elderly patients.

Treatment outcome of acute myeloid leukemia (AML) in elderly patients remains unsatisfactory. It has been shown that the infusion of granulocyte colony-stimulating factor-mobilized donor peripheral blood stem cells (G-PBSCs) can enhance graft-versus-leukemia effects and speed hematopoietic recovery. Fifty-eight AML patients aged 60-88 years were randomly assigned to receive induction chemotherapy with cytarabine and mitoxantrone (control group; n = 28) or it plus human leukocyte antigen-mismatched G-PBSCs (G-PBSC group; n = 30). Patients who achieved complete remission received another 2 cycles of postremission therapy with intermediate-dose cytarabine or it plus G-PBSCs. The complete remission rate was significantly higher in the G-PBSC group than in the control group (80.0% vs 42.8%; P = .006). The median recovery times of neutrophils and platelets were 11 days and 14.5 days, respectively, in the G-PBSC group and 16 days and 20 days, respectively, in the control group after chemotherapy. The 2-year probability of disease-free survival was significantly higher in the G-PBSC group than in the control group (38.9% vs 10.0%; P = .01). No graft-versus-host disease was observed in any patient. Persistent donor microchimerism was successfully detected in all of the 4 female patients. These results indicate that G-PBSCs in combination with conventional chemotherapy may provide a promising treatment method for AML in elderly patients.