PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior immunotherapy or cytokine treatment and recovered No prior hematologic stem cell transplantation Chemotherapy: See Disease Characteristics At least 4 weeks since prior chemotherapy (at least 6 weeks since prior nitrosoureas) and recovered Endocrine therapy: Not specified Radiotherapy: See Disease Characteristics At least 4 weeks since prior radiotherapy and recovered No prior radioimmunotherapy Surgery: Not specified Other: No concurrent IV antibiotics