PRIOR CONCURRENT THERAPY: No concurrent therapy with other anticancer agents No concurrent immunosuppressive agents (e.g., cyclosporin) Biologic therapy: Prior interferon alpha allowed Chemotherapy: At least 4 weeks since systemic chemotherapy with recovery required Endocrine therapy: No concurrent corticosteroids Radiotherapy: At least 4 weeks since radiotherapy Surgery: Adequate recovery required Other: No prior organ allograft