PRIOR CONCURRENT THERAPY: Biologic therapy: See Disease Characteristics Chemotherapy: See Disease Characteristics At least 3 weeks since prior chemotherapy (6 weeks for nitrosamines and mitomycin) No concurrent chemotherapy Endocrine therapy: See Disease Characteristics No concurrent systemic corticosteroid therapy No concurrent hormonal therapy Radiotherapy: See Disease Characteristics At least 3 weeks since prior radiotherapy No concurrent radiotherapy Surgery: See Disease Characteristics Other: No concurrent immunosuppressive drugs No other concurrent experimental protocol No other concurrent antitumor therapy