Donor Peripheral Stem Cell Transplant in Treating Patients With Relapsed Acute Myeloid Leukemia

OBJECTIVES: Primary * Evaluate the in vivo expansion of natural killer (NK) cells 14 days after treatment with allogeneic NK cell-enriched peripheral blood stem cell transplantation in patients with relapsed acute myeloid leukemia. Secondary * Determine the response rate, in terms of complete remission, in patients treated with this regimen. * Correlate complete remission rate with NK cell expansion, interleukin-15 levels, and donor/recipient killer immunoglobulin receptor (KIR) ligand matching status in patients treated with this regimen. * Determine the overall and progression-free survival of patients treated with this regimen. * Determine the toxicity of this regimen in these patients. OUTLINE: This is an open-label study. * Induction therapy: Patients receive fludarabine IV on days -6 to -2 and cyclophosphamide IV on day -5 or on days -5 and -4. * Allogeneic natural killer (NK) cell-enriched peripheral blood stem cell transplantation: Patients receive allogeneic NK cell-enriched peripheral blood stem cells IV over 15-60 minutes on day 0. Patients also receive interleukin-2 subcutaneously beginning on day 0 and continuing 3 times a week for up to 2 weeks. After completion of study treatment, patients are followed periodically for 3 months.