Background: Chronic airway inflammation is a feature of asthma. Increased levels of cysteinyl leukotrienes (cys-LTs; leukotriene [LT]C4, LTD4, LTE4) have been shown in the exhaled breath condensate (EBC) of children with moderate-to-severe asthma. The aim of this study was to examine the relationship between EBC cys-LTs (LTE4) levels and bronchial hyperreactivity in children with mild asthma in order to evaluate the clinical utility of measuring EBC cys-LTs levels.
Methods: We measured LTE4 levels in the EBC of children aged 8 to 18 years, including healthy nonasthmatic children (n = 6) and children with mild asthma (n = 37). Patients with mild asthma were classified into the following three groups: group 1, participants who had been asymptomatic (no wheezing/symptoms of asthma) for > 6 months prior to examination (n = 12); group 2, participants who were asymptomatic but had had wheezing/symptoms of asthma within 6 months before examination (n = 18); and group 3, patients with current wheeze and/or mild symptoms of asthma exacerbation at the time of examination.
Results: Exhaled LTE4 levels were increased in all children with mild asthma compared with nonasthmatic control subjects (5.69 ± 9.62 pg/20 min vs 0.74 ± 0.79 pg/20 min, p < 0.05) [mean ± SD]. In particular, the EBC LTE4 levels in group 2 (4.99 ± 6.70 pg/20 min) and group 3 (14.66 ± 17.11 pg/20 min) were increased compared with control subjects and group 1 (1.50 ± 1.69 pg/20 min). The EBC LTE4 levels negatively correlated with the provocative concentration of methacholine causing a 15% fall in FEV1 (r = − 0.454, p = 0.012).
Conclusion: EBC cys-LTs may be useful as a noninvasive marker assessing airway inflammation and hyperreactivity in children with asthma.