Changes in airway inflammation and hyperresponsiveness after inhaled corticosteroid cessation in allergic asthma.

Background: Most patients with asthma are currently controlled by pharmacotherapeutic means such as inhaled corticosteroid (ICS). However, whether ICS actually induces remission of asthma remains unknown. The present study evaluates changes in airway inflammation and hyperresponsiveness in adult patients with asthma after stopping ICS.

Methods: We enrolled 11 patients with allergic asthma (7 males and 4 females; mean age, 52.3 years) who had been asymptomatic and had no exacerbation by low-dose ICS. Airway hyperresponsiveness (AHR) was assessed using methacholine challenge, and induced sputum was evaluated before and every 3 months after ICS cessation during the 1-year follow-up.

Results: Among the 11 asthmatics, AHR increased in 10 (90.9%) and asthma clinically relapsed in 4 (36.4%) within 1 year of ICS cessation. AHR increased in all 7 asthmatics that were sensitized to Dermatophagoides farinae and asthma clinically relapsed in 4 (57.1%) of them. Furthermore, eosinophil numbers and IL-4 concentrations in the sputum significantly increased after ICS cessation.

Conclusions: Remission with normal airway response to methacholine (no AHR) might be rare in adult patients with allergic asthma, and sensitization to house dust mites appears to play an important role in relapse. Therefore, ICS cessation should be carefully considered in patients sensitive to house dust mites. Serial determination of eosinophil counts or IL-4 concentrations in sputum might be appropriate for monitoring and preventing asthma relapse in adults.