Airflow limitation and airway inflammation of asthmatic adolescents in remission

Background: Airflow limitation and airway inflammation have been suggested to persist even in remitted asthmatic adolescents. Aim: We wanted to know the details of airflow limitation and airway inflammation in remitted asthmatic adolescents by performing airway reversibility test (ART) and fractional exhaled nitric oxide (FENO) measurements, respectively. Methods: ART and FENO were examined for 21 asthmatic subjects (aged 8 - 18years old) in remission. Remission was defined as having no asthmatic attacks for, at least, 12 months, and not taking any asthma medications for, at least, 3 months. ART was evaluated by comparing lung functions before and after a bronchodilator inhalation. PEF and V50 were used as parameters for central and peripheral airways, respectively. Thirty age-matched asthmatics taking daily medications were also examined as control. Results: ART revealed that percentages of high responders to bronchodilators (more than 20% improvements) were 29 % and 67 % in central and peripheral airways, respectively. FENO level was high (mean 65.6 ± 9.5 ppb) irrespective of the pattern of ART, and was not different from that of control. Among subjects in remission, FENO value of those with severe persistent asthma in the past was significantly higher than those with mild or moderate degree. In addition, it was getting higher as the periods from the end of medication was longer (P Conclusion: Regular examinations of airflow limitation and airway inflammation would be required for remitted asthmatics in order to know their exact status of “remission”.