BACKGROUNDStudies of interleukin (IL)-4 and IL-6 in the exhaled breath condensate (EBC) of asthmatic patients are limited. This study was to determine the effect of inhaled corticosteroid (ICS) treatment on IL-4 and IL-6 in the EBC of asthmatic patients.

METHODSIn a prospective, open-label study, budesonide 200 μg twice daily by dry powder inhaler was administered to 23 adult patients with uncontrolled asthma (mean age 42.7 years) for 12 weeks. Changes in asthma scores, lung function parameters (forced expiratory volume in 1 s [FEV1], peak expiratory flow [PEF], forced expiratory flow at 50% of forced vital capacity [FEF50], forced expiratory flow at 75% of forced vital capacity, maximum mid-expiratory flow rate) and the concentrations of IL-4 and IL-6 in EBC were measured.

RESULTSBoth asthma scores and lung function parameters were significantly improved by ICS treatment. The mean IL-4 concentration in the EBC was decreased gradually, from 1.92 ± 0.56 pmol/L before treatment to 1.60 ± 0.36 pmol/L after 8 weeks of treatment (P < 0.05) and 1.54 ± 0.81 pmol/L after 12 weeks of treatment (P < 0.01). However, the IL-6 concentration was not significantly decreased. The change in the IL-4 concentration was correlated with improvements in mean FEV1, PEF and FEF50 values (correlation coefficients -0.468, -0.478, and -0.426, respectively).

CONCLUSIONSThe concentration of IL-4 in the EBC of asthmatic patients decreased gradually with ICS treatment. Measurement of IL-4 in EBC could be useful to monitor airway inflammation in asthmatics.