Abstract

Background: Leukotriene-like immunoreactivity has been detected in exhaled breath condensate (EBC), but definitive evidence for the presence of leukotrienes (LTs) in this biological fluid is not available. A study was undertaken to determine whether LTC₄, LTD₄, LTE₄, and LTB₄ are measurable in EBC by gas chromatography/mass spectrometry and to quantify exhaled LTs in adults and children with asthma and in control subjects.

Methods: Twenty eight adults and 33 children with mild to moderate persistent asthma treated with inhaled corticosteroids and age matched healthy controls (50 adults and 50 children) were studied. LTB₄, LTC₄, LTD₄, and LTE₄ in EBC were measured by gas chromatography/mass spectrometry.

Results: LTD₄, LTE₄, and LTB₄ were detectable in all samples. Concentrations of LTC₄ in EBC were either close to or below the detection limit of 1 pg/ml. Median exhaled LTD₄, LTE₄, and LTB₄ concentrations in asthmatic adults were increased 4.1-fold (p<0.001), 1.8-fold (p<0.01), and 2.6-fold (p<0.001), respectively, compared with values in healthy adults. Median exhaled LTD₄, LTE₄, and LTB₄ concentrations in asthmatic children were increased 2.8-fold (p<0.001), 1.3-fold (p<0.001), and 1.6-fold (p<0.001), respectively, compared with those in healthy children. In patients with asthma there was a correlation between exhaled LTD₄ and LTE₄ in both adults (r = 0.87, p<0.0001) and children (r = 0.78, p<0.0001).

Conclusions: Gas chromatography/mass spectrometry can be used to accurately quantify exhaled LTs which are increased in asthmatic adults and children compared with controls.