Patients receive rituximab intravenously (IV) on day 1, etoposide IV on days 2-4, carboplatin IV on day 3, and ifosfamide IV on day 3 over 24 hours. Patients also receive filgrastim subcutaneously (SC) once daily beginning on day 6 and continuing until apheresis is completed and plerixafor SC once daily for up to 4 days beginning 24 hours after recovery from nadir and continuing until apheresis is completed. Patients may undergo up to 4 apheresis procedures until the optimal number of CD34+ cells are collected.