PATIENT CHARACTERISTICS: Age: Not specified Performance status: ECOG 0-2 Life expectancy: At least 3 months Hematopoietic: If less than 50% plasma cells in bone marrow: WBC at least 2,500/mm3 OR Absolute neutrophil count at least 1,000/mm3 (greater than 500/mm3 if platelet count at least 75,000/mm3) Platelet count greater than 45,000/mm3 (thrombocytopenia related to idiopathic thrombocytopenic purpura or vitamin B12 or folate deficiency allowed) Hepatic: Bilirubin no greater than 2 times upper limit of normal (ULN) ALT or AST less than 2 times ULN (if greater than one third of liver involved, then no greater than 5 times ULN) No severe hepatic disease Renal: Creatinine no greater than 2.0 mg/dL Other: No severe infection requiring intravenous antibiotics Not pregnant or nursing Fertile patients must use effective contraception No prior malignancy within 5 years except for treated basal cell or squamous cell skin cancer, or carcinoma in situ of the cervix No Type I hypersensitivity or anaphylactic reactions to murine proteins or to any component of rituximab