학술논문

High fractional exhaled nitric oxide and sputum eosinophils are associated with an increased risk of future virus-induced exacerbations: A prospective cohort study.
Document Type
Article
Source
Clinical & Experimental Allergy. Aug2017, Vol. 47 Issue 8, p1007-1013. 7p.
Subject
*GRANULOCYTES
*EOSINOPHILS
*LEUCOCYTES
*SPUTUM
*SALIVA
Language
ISSN
0954-7894
Abstract
Background The major trigger of asthma exacerbations is infection with a respiratory virus, most commonly rhinovirus. Type 2 inflammation is known to be associated with an increased risk of exacerbations in general. Whether type 2 inflammation at baseline increases the risk of future virus-induced exacerbations is unknown. Objective To assess whether type 2 inflammation is associated with an increased risk of virus-induced exacerbations of asthma. Methods Stable asthmatics had spirometry, skin prick test, measurement of Fe NO and sputum induced for differential cell counts. Patients were followed up for 18 months, during which they were assessed at the research unit when they had symptoms of an exacerbation. Nasal swabs collected at these assessments underwent viral detection by PCR. Results A total of 81 asthma patients were recruited, of which 22 (27%) experienced an exacerbation during the follow-up period. Of these, 15 (68%) had a respiratory virus detected at exacerbation. Sputum eosinophils >1% at baseline increased the risk of having a subsequent virus-induced exacerbation ( HR 7.6 95% CI: 1.6-35.2, P=.010) as did having Fe NO >25 ppb ( HR 3.4 95% CI: 1.1-10.4, P=.033). Conclusion and Clinical Relevance Established type 2 inflammation during stable disease is a risk factor for virus-induced exacerbations in a real-life setting. Measures of type 2 inflammation, such as sputum eosinophils and Fe NO, could be included in the risk assessment of patients with asthma in future studies. [ABSTRACT FROM AUTHOR]