OBJECTIVES: I. Evaluate the 1 and 2 year event free survival of patients with poor prognosis, relapsed or refractory intermediate or high grade B-cell non-Hodgkin's lymphoma who receive high dose carmustine and melphalan plus gemcitabine followed by rituximab (IDEC-C2B8 monoclonal antibody; anti-CD20 monoclonal antibody) plus sargramostim and consolidation chemotherapy with alternating dexamethasone/cyclophosphamide/ etoposide/cisplatin plus gemcitabine and paclitaxel/cisplatin and compare these figures to a historical control population. II. Evaluate the ability of posttransplant rituximab therapy in combination with sargramostim (GM-CSF) to control and further treat residual lymphoma remaining after high dose therapy in these patients.

III. Evaluate quality of life parameters and assess the risk of secondary malignancies following this treatment regimen in these patients.

OUTLINE: Patients receive high dose gemcitabine IV over 100 minutes on day -5 and again approximately 6 hours after carmustine IV over 2 hours on day -2.

On day -1, patients receive melphalan IV over 20 minutes followed 24 hours later (day 0) with peripheral blood stem cells transplantation. Patients then receive sargramostim (GM-CSF) subcutaneously beginning on day 4 until granulocyte count is greater than 1,000/mm3 for 2 consecutive days. At weeks 5-8 posttransplant, patients receive rituximab (IDEC-C2B8 monoclonal antibody; anti-CD20 monoclonal antibody) IV over 3-4 hours weekly. Prior to rituximab treatment at week 4 posttransplant, patients receive sargramostim (GM-CSF) subcutaneously 3 times a week continuing through rituximab therapy. At approximately 3 and 9 months posttransplant, patients receive dexamethasone orally every day for days 1-4, and cyclophosphamide, etoposide, and cisplatin by continuous infusion for 4 days (days 1-4), and gemcitabine IV over 100 minutes on days 1 and 5. At approximately 6 and 12 months posttransplant, patients receive paclitaxel IV over 6 hours on day 2 and cisplatin IV over 24 hours on day 3. Patients are followed at least every 6 weeks to 3 months until death.

PROJECTED ACCRUAL: An estimated 25 patients per year will be accrued into this study.