It is recognized that airway inflammation has a central role in the pathogenesis of asthma, but how it relates to exercise-induced bronchoconstriction (EIB) is not completely understood.

The aim of our study was to investigate the relationship between EIB and baseline concentrations of cysteinyl leukotrienes (Cys-LTs) and other inflammatory markers in exhaled breath condensate (EBC).

EBC was collected, and the fraction of exhaled nitric oxide (FE_NO) was measured in a group of 19 asthmatic children, after which they performed a treadmill exercise test. Fourteen healthy children were enrolled as control subjects.

The asthmatic children were divided into the EIB group (decrease in FEV₁, ≥12%) and the non-EIB group. The EBC was analyzed for the presence of Cys-LTs, leukotriene B₄, and ammonia. Asthmatic patients with EIB (mean FEV₁ decrease, 23% ± 3%) had higher Cys-LT concentrations than either asthmatic patients without EIB or control subjects (42.2 pg/mL [median] vs 11.7 pg/mL and 5.8 pg/mL; P < .05 and P < .001, respectively). Ammonia concentrations were lower in both the EIB and non-EIB groups than in control subjects (253.2 μM and 334.6 μM vs 798.4 μM; P < .01 and P < .05, respectively). No difference in EBC leukotriene B₄ levels was found among the 3 groups. Both asthmatic groups had higher FE_NO levels than control subjects (P < .001). EBC Cys-LT (P < .01; r=0.7) and FE_NO (P < .05; r=0.5) values both correlated significantly with the postexercise FEV₁ decrease.

this study shows that EBC Cys-LT values are higher in asthmatic children with EIB and correlate with the decrease in FEV₁ after exercise. These findings suggest that the pathways of both Cys-LT and nitric oxide are involved in the pathogenesis of EIB.