PRIOR CONCURRENT THERAPY: Biologic therapy: See Disease Characteristics At least 4 weeks but no more than 12 weeks since prior initial therapy and recovered Chemotherapy: See Disease Characteristics At least 4 weeks but no more than 12 weeks since prior initial therapy and recovered Endocrine therapy: See Disease Characteristics At least 4 weeks but no more than 12 weeks since prior initial therapy and recovered No concurrent corticosteroids Radiotherapy: See Disease Characteristics At least 4 weeks but no more than 12 weeks since prior initial therapy and recovered No prior radiotherapy to the spleen Surgery: No prior splenectomy