OUTLINE: Patients receive two doses of rituximab IV over 3-4 hours 1 week apart. Stem cells from the peripheral blood or bone marrow are collected at least 1 week after the second dose of rituximab. Following stem cell collection, patients receive a third dose of rituximab IV as above between days -10 and -6. Patients then receive high-dose chemotherapy consisting of carmustine IV on day -6, etoposide IV twice daily and cytarabine IV on days -5 to -2, and melphalan IV on day -1. On day 0 patients undergo autologous bone marrow or peripheral blood stem cell transplantation. After transplantation, patients receive a fourth dose of rituximab as above at approximately day 30, and then weekly over 4 weeks at approximately 6 months in the absence of disease progression or unacceptable toxicity. Patients are followed at 1 year and then annually thereafter.