OUTLINE: Patients receive filgrastim (G-CSF) subcutaneously (SC) twice daily on days 1-7. Peripheral blood stem cells (PBSC) are collected on days 5-7. Patients receive cyclophosphamide IV over 2 hours, mitoxantrone IV, and cytarabine IV every 12 hours for 2 doses on day 10, and dexamethasone every 12 hours for 4 doses on days 10 and 11. Patients receive G-CSF SC for the next 10-20 days. Additional PBSC are collected on days 25-28 or 29. Beginning 7 days before PBSC transplantation, patients receive cyclophosphamide IV over 2 hours on days -7 and -6 and total body irradiation (TBI) twice daily on days -4 to -1. Patients unable to tolerate TBI receive cyclophosphamide IV over 2 hours on days -6 to -3, carmustine IV over 1 hour on days -6, and etoposide IV over 1 hour every 12 hours on days -6 to -4. Retrovirally transduced PBSC are reinfused on day 0 followed by another course of G-CSF SC until hematopoietic recovery.