Stem Cell Transplant With Specially Treated Cells in Treating Patients With Acute Leukemia

• To assess the feasibility of ex vivo expanding a CD34 selected, mafosfamide purged autograft.
  
• To assess the duration of aplasia associated with mafosfamide purging and ex vivo cytokine expanded autografting for high risk acute leukemia.
  
• To estimate the event-free survival following mafosfamide purging and ex vivo cytokine expanded autografting for high risk acute leukemia
  

• To obtain blood samples for future laboratory studies that may include immune reconstitution.
  

Patients will receive infusions of cyclophosphamide and an infusion or injection of G-CSF once a day for 7-14 days followed by collection of their peripheral stem cells. Some patients may also undergo bone marrow collection. Patients' stem cells and/or bone marrow will be treated in the laboratory. Patients will then receive busulfan for 4 days followed by cyclophosphamide for 4 days. Two days later, patients will undergo autologous peripheral stem cell or bone marrow transplant and then receive an infusion or injection of G-CSF once a day until blood counts return to normal.

The goal of this pilot clinical study is to shorten the duration of aplasia associated with mafosfamide purged autologous transplants for acute leukemia using the cytokine cocktail of recombinant human stem cell factor (rhSCF), recombinant human granulocyte colony stimulating factor (rhG-CSF) and recombinant human thrombopoeitin (rhTPO) for ex vivo expansion.

After finishing treatment, patients will be evaluated periodically for at least 5 years.