Materials and Methods

Study Subjects Twelve asthmatic patients (19 to 67 yr; mean±SD, 42.7±16.5 yr) took part in the study. Asthma was defined as previously described (2), according to the criteria of the American Thoracic Society (16), and all patients had a reversible airways obstruction. The severity of asthma was assessed by the clinical score of Aas (17) and the pulmonary function of the patients (spirometric measurement of forced expiratory volume in 1 second [FEVl] and forced vital capacity). None of the subjects were smokers, and no subject had any respiratory tract infection during the month preceding the test. Patients were excluded from the study if they had had a severe exacerbation of asthma requiring hospitalization during the month preceding the study. Because drugs may alter c-fos expression, patients were excluded if they had taken systemic corticosteroids of any form during the past 2 months, inhaled corticosteroids the previous month, nedocromil sodium, sodium cromoglycate, or ketotifene the week before, and theophylline in the previous 48 h./1ragonists were only withdrawn for 8 h for safety reasons. Ten nonsmoking normal subjects (18 to 67 yr; mean±SD, 38.8±17.4 yr) were used as a control group. Their pulmonary function was within normal range and they were nonallergic and had never suffered from asthma. No subject had suffered from any respiratory tract infection during the month preceding the test.