--Disease Characteristics-- Cystic fibrosis No mild genetic mutations, i.e., normal nasal chloride ion permeability At least 2 weeks since decrease in pulmonary function --Prior/Concurrent Therapy-- At least 3 months since systemic cortisone At least 1 month since other therapeutic research study, e.g., DNAse --Patient Characteristics-- Other: Adequate endocrine, liver, kidney, and cardiac function Adenovirus antibody seropositive No pregnant or nursing women Negative pregnancy test required of fertile women Adequate contraception required of fertile patients