Gas chromatography/mass spectrometry analysis of exhaled leukotrienes in asthmatic patients

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 LTC(4), LTD(4), LTE(4), and LTB(4) are measurable in EBC by gas chromatography/mass spectrometry and to quantify exhaled LTs in adults and children with asthma and in control subjects.

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. LTB(4), LTC(4), LTD(4), and LTE(4) in EBC were measured by gas chromatography/mass spectrometry.

LTD(4), LTE(4), and LTB(4) were detectable in all samples. Concentrations of LTC(4) in EBC were either close to or below the detection limit of 1 pg/ml. Median exhaled LTD(4), LTE(4), and LTB(4) 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 LTD(4), LTE(4), and LTB(4) 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 LTD(4) and LTE(4) in both adults (r = 0.87, p<0.0001) and children (r = 0.78, p<0.0001).

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