Increased leukotriene B4 and interleukin-6 in exhaled breath condensate in cystic fibrosis

Chronic neutrophilic airway inflammation is an important feature of cystic fibrosis (CF). Noninvasive inflammatory markers may be useful in monitoring CF. Leukotriene B4 (LTB4) and interleukin (IL)-6 are inflammatory mediators that are increased in chronic neutrophilic inflammation. The aim of this study was to assess whether LTB4 and IL-6 were increased in exhaled breath condensate of CF patients and whether they could be used to monitor inflammation. Twenty patients with CF (13 males, age of 28 ± 9 years) were recruited together with 15 age-matched healthy subjects (8 males, age 35 ± 7 years). LTB4 and IL-6 levels were markedly elevated in patients with acute exacerbations (28.8 ± 4.3 and 8.7 ± 0.4 pg/ml) compared with control subjects (6.8 ± 0.7 and 2.6 ± 0.1 pg/ml, p < 0.0001). We also observed a decrease of exhaled LTB4 and IL-6 concentrations after antibiotic treatment in six patients who were followed until clinically stable (31.1 ± 4.4 and 9.5 ± 0.4 pg/ml vs. 18.8 ± 0.8 and 6.4 ± 0.2 pg/ml, respectively) and an increase in 15 CF patients infected with Pseudomonas aeruginosa (34.3 ± 5.0 and 9.3 ± 0.3 pg/m) compared with those infected with other bacteria (18.3 ± 0.7 and 6.9 ± 0.5 pg/ml). These findings suggest that LTB4 and IL-6 levels are increased in exhaled breath condensate of patients with CF during exacerbation and could be used to monitor airway inflammation in these patients.