Sputum cysteinyl leukotrienes increase 24 hours after allergen inhalation in atopic asthmatics

We have used the relatively noninvasive technique of induced sputum to meas ure allergen-induced changes in the concentration of eicosanoid mediators i n bronchial secretions from atopic asthmatics. Sputum induction was perform ed before and 24 h after inhalational allergen challenge in 14 atopic asthm atics who developed a late asthmatic reaction (LAR). Differential cell coun ts were made on sputum cytospins and eicosanoid (cysteinyl leukotrienes [cy s LTs], prostaglandin D-2 [PGD(2)], and PGE(2)) concentrations were measure d in the sputum supernatants. The percentage of eosinophils at baseline cor related with the concentration of cys LTs (r = 0.84 p < 0.001) but not pros tanoid mediators. Allergen challenge produced a significant increase in the concentration of sputum cys LTs from 3.45 ng/ml sputum to 11.95 ng/ml (p = 0.002), which correlated with the increase in sputum eosinophils (r = 0.55 , p < 0.05). There were no significant changes in PGD(2) or PGE(2) concentr ations in sputum supernatants in response to challenge. Thus, the noninvasi ve technique of induced sputum has been used to demonstrate increased cys L Ts, but not prostanoids associated with LAR after allergen challenge. The c orrelation between eosinophil numbers and cys LT concentrations at baseline values and 24 h after allergen challenge is consistent with these cells be ing a principal source of cys LTs within the airways at these time points.