URINARY-EXCRETION OF LEUKOTRIENE-E4 AND 11-DEHYDRO-THROMBOXANE-B2 IN RESPONSE TO BRONCHIAL PROVOCATIONS WITH ALLERGEN, ASPIRIN, LEUKOTRIENE-D4, AND HISTAMINE IN ASTHMATICS

In vivo production of thromboxane (TX) A2 and the cysteinyl-containing leukotrienes (LT) C4, D4, and E4 in correlation to airway responses was studied. Bronchial provocation with specific allergen in atopic asthmatics was followed by a significant increase in urinary concentration of immunoreactive LTE4 (34 +/- 6 before versus 56 +/- 7 ng/mmol creatinine after allergen challenge; n = 5) and 11-dehydro-TXB2 (164 +/- 29 versus 238 +/- 25 ng/mmol creatinine). In the presence of the leukotriene-antagonist ICI-204,219, which significantly Increased the PD20 for allergen, the increment in urinary excretion of LTE4 was even higher (60 +/- 8 versus 288 +/- 128 ng/mmol creatinine; n = 5). In contrast, provocation with histamine (n = 5) did not provoke release of leukotrienes orthromboxane, nor was inhalation of LTD4 (n = 7) associated with increased urinary concentration of 11-dehydro-TXB2. Furthermore, bronchoconstriction induced by inhalation of lysine-aspirin in aspirin-sensitive asthmatics (n = 4) was followed by increased levels of LTE4 in the urine, whereas the levels of 11-dehydro-TXB2 remained the same. Finally, the basal levels of LTE4 in the urine of nine aspirin-sensitive asthmatics were elevated as compared with 15 other asthmatics (112 +/- 54 versus 38 +/- 20 ng/mmol creatinine, p < 0.001). The findings support that the cysteinyl-leukotrienes are potential mediators of allergen-induced asthma and that the release of LTE4 and 11-dehydro-TXB2 into the urine appeared to be a direct and dose-dependent effect of the antigen-antibody reaction. Moreover, the findings in aspirin-sensitive asthmatics indicate that cysteinyl-leukotrienes may be of particular importance in the pathogenesis of aspirin-asthma.