Association of urinary leukotriene E4 excretion during aspirin challenges with severity of respiratory responses

Background: Asthmatics with aspirin- (ASA) sensitive respiratory disease (ASRD) have a spectrum of respiratory reactions during oral ASA challenge that vary in severity and are temporally associated with leukotriene (LT) formation. Objective: This study investigates the relationship of the severity of ASA-induced respiratory reactions to urinary LTE4 excretion. Methods: Asthmatics with suspected ASRD underwent oral ASA challenges. Urinary LTE4 levels were measured at baseline, during the reaction, and after acute ASA desensitization. Results: Asthmatics who had respiratory reactions during oral ASA challenges were divided into 3 groups: asthmatics with naso-ocular reactions and <15% decline from baseline FEV1 values (group 1), asthmatics with a decline in FEV1 of 20% to 30% (group 2), and asthmatics with a decline in FEV1 of >30% (group 3), There were no significant differences in age, baseline FEV1 values, use of inhaled corticosteroids, daily prednisone doses, prednisone bursts, duration of reactions, or average provoking doses of ASA among the groups. At baseline group 3 asthmatics had significantly higher urinary LTE4 levels than those in groups 1 or 2, At the time of respiratory reaction to ASA, the urinary LTE4 levels rose significantly in ail groups but were significantly greater among group 3 asthmatics compared with those in groups 1 and 2, Conclusion: The severity of the respiratory reactions during oral ASA challenges was associated with the degree of elevation of baseline LTE4 synthesis, Our results suggest that asthmatics with ASRD have a spectrum of respiratory tract reactions in which leukotrienes play a distinguishing role.