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

RATIONALE: Giving chemotherapy before a donor peripheral blood stem cell transplant helps stop the growth of cancer cells. It also helps stop the patient's immune system from rejecting the donor's stem cells. When the healthy stem cells and natural killer (NK) cells from a donor are infused into the patient they may help the patient's bone marrow make stem cells, red blood cells, white blood cells, and platelets. PURPOSE: This clinical trial is studying how well a peripheral stem cell transplant using NK cells from a donor works 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.