Markers of Airway Inflammation in the Exhaled Breath Condensate of Preschool Wheezers

Background: Leukotrienes (LT), isoprostanes, and nitrites/nitrates are biomarkers of airway inflammation and oxidative stress that can be detected in exhaled breath condensate (EBC). The aim of this study was to evaluate LTB4, LTE4, 8-isoprostane, and nitrite/nitrate levels in the EBC of healthy and wheezing preschool children. Methods: We included 21 healthy nonatopic children and 25 patients with recurrent wheezing episodes in a cross-sectional study. LTB4, LTE4, and 8-isoprostane concentrations were measured directly in EBC using a specific enzyme immunoassay; nitrite/nitrate concentrations were measured using a colorimetric assay. Results: LTB4 concentrations were higher in children with wheezing episodes than in healthy controls (76 pg/mL vs 20 pg/mL, P<.001). LTE4 was increased in children with wheezing episodes than in healthy controls (68 pg/mL vs 35 pg/mL, P<.001). Nitrite concentrations were higher in children with wheezing episodes than in healthy controls (14 pg/mL vs 9.7 pg/mL, P<.03). We found no differences in 8-isoprostane and nitrate concentrations between the patients and the healthy controls. Conclusions: Our findings suggest that EBC is a suitable noninvasive method for the assessment of airway inflammation and oxidative stress in preschool children. Levels of LTB4, LTE4, and nitrites were higher in children with recurrent wheezing episodes than in healthy controls.