RESUMO
BACKGROUND: The inhibitory effect of corticosteroids (CS) on the secretions of cysteinyl-leukotrienes (Cys-LTs) in asthma is controversial. The aim of this study was to evaluate the effect of CS on allergen-induced increase in urinary leukotriene E4 (uLTE4) during early (EAR) and late (LAR) asthmatic responses in mild untreated asthmatics. MATERIAL AND METHODS: Nine subjects with mild untreated allergic asthma performed two allergen challenges, after 1-week treatment with beclomethasone dipropionate (BDP, 500 microg b.i.d) or placebo. Forced Expiratory Volume in one second 1 (FEV1) was monitored to assess EAR and LAR, and uLTE4 was measured before and during EAR and LAR. RESULTS: After placebo, uLTE4 increased significantly during EAR, but not during and after LAR, in comparison with baseline values. Beclomethasone dipropionate induced a significant attenuation of the uLTE4 increase during EAR, in comparison with placebo, in association with a good protection of LAR (P = 0.002) and a mild protection of EAR (P = 0.07). CONCLUSIONS: Beclomethasone dipropionate blunts the early increase in uLTE4 excretion due to allergen challenge, in association with a significant effect on the severity of LAR. These data support the hypothesis that inhaled CS may inhibit the allergen-induced release of cys-LTs in asthma.
