Association of urinary leukotriene E-4 excretion during aspirin challengeswith severity of respiratory responses

Background: Asthmatics with aspirin- (ASA) sensitive respiratory disease (A SRD) have a spectrum of respiratory reactions during oral ASA challenge tha t vary in severity and are temporally associated with leukotriene (LT) form ation. 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. Urin ary LTE4 levels were measured at baseline, during the reaction, and after a cute ASA desensitization. Results: Asthmatics who had respiratory reactions during oral ASA challenge s 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 va lues, use of inhaled corticosteroids, daily prednisone doses, prednisone bu rsts, duration of reactions, or average provoking doses of ASA among the gr oups. 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 sign ificantly greater among group 3 asthmatics compared with those in groups 1 and 2, Conclusion: The severity of the respiratory reactions during oral ASA chall enges was associated with the degree of elevation of baseline LTE4 synthesi s, Our results suggest that asthmatics with ASRD have a spectrum of respira tory tract reactions in which leukotrienes play a distinguishing role.