Gemcitabine Hydrochloride, Carboplatin, Dexamethasone, and Rituximab in Treating Patients With Previously Treated Lymphoid Malignancies

OBJECTIVES: I. To determine the feasibility and safety of Gemcitabine/Carboplatin/Dexamethasone with or without Rituximab in previously treated lymphoid malignancies (rituximab will only be evaluated in CD20 positive malignancies). II. To determine the efficacy of the above regimen. III. To determine the ability to proceed to blood stem peripheral blood collection following the above regimens (the impact of above regimen on stem cell reserve). IV. To determine remission duration. All patients are treated with gemcitbine, carboplatin, and dexamethasone. Patients with CD20 + lymphomas also receive rituximab. After completion of study treatment, patients are followed up at 3-4 weeks and then every 6 months for 5 years.