Induced sputum eicosanoid concentrations in asthma

Further definition of the role of leukotrienes (LT) and prostaglandins (PG) in asthma would be helped by a noninvasive method for assessing airway pro duction. The supernatant from sputum induced with hypertonic saline and dis persed using dithiotrietol has been successfully used to measure other mole cular markers of airway inflammation and might be a useful method. We have measured induced sputum supernatant LTC4/D-4/E-4 concentrations using enzym e immunoassay and PGE(2), PGD(2), TXB2, and PGF(2 alpha), using gas chromat ography-negative ion chemical ionization-mass spectroscopy in 10 normal sub jects and in 26 subjects with asthma of variable severity. Sputum cysteinyl -leukotrienes concentrations were significantly greater in subjects with as thma (median, 9.5 ng/ml) than in normal control subjects (6.4 ng/ml; p < 0. 02) and greater in subjects with persistent asthma requiring inhaled cortic osteroids (median, 11.4 ng/ml) or studied within 48 h of an acute severe ex acerbation of asthma (13 ng/ml) than in subjects with episodic asthma treat ed with inhaled beta(2)-agonists only (7.2 ng/ml). There were no significan t differences in the concentrations of other eicosanoids between groups, al though there was a negative correlation between the percentage sputum eosin ophil count and sputum PGE(2) concentration (r = -0.48; p < 0.01) in subjec ts with asthma. We conclude that induced sputum contains high concentration s of eicosanoids and that sputum LTC4/D-4/E-4 concentrations are significan tly greater in subjects with asthma than in normal subjects. The inverse re lationship between eosinophilic airway inflammation and sputum PGE(2) conce ntration would be consistant, with the latter having an anti-inflammatory r ole.