Exhaled Nitric Oxide and Bronchial Reactivity During and After Inhaled Beclomethasone in Mild Asthma

The measurement of exhaled nitric oxide (ENO) is recognized as a marker of airway inflammation. ENO was measured in 10 nonsteroid-treated asthmatics at recruitment, during 3 weeks of inhaled beclomethasone (1000 µg/day) and for 3 weeks after withdrawal. Baseline ENO was increased in asthma compared with nonasthmatics (85.0 ± 54.5 vs. 24.5 ± 14.8 ppb, p < 0.0001). After inhaled steroid, there was no significant change in forced expiratory volume in 1 sec (FEV1) and forced vital capacity (FVC), but methacholine PC20 rose significantly (p = 0.0345). ENO (mean ± SD; % baseline) fell after 1 week on steroid to 60.6 ± 31.1 and rose to 95.3 ± 46.1 at 1 week after withdrawal. ENO did not correlate with PC20 or FEV1. The changes in ENO and PC20 were inversely correlated (r2 = 0.325). ENO may bean index of airway inflammation and therapeutic response in bronchial asthma.