DIFFERENTIAL INHIBITORY EFFECT OF REGULAR INHALED CORTICOSTEROID ON AIRWAY RESPONSIVENESS TO ADENOSINE-5' MONOPHOSPHATE, METHACHOLINE, AND BRADYKININ IN SYMPTOMATIC CHILDREN WITH RECURRENT WHEEZE

Indirect tests of bronchial responsiveness to agents such as adenosine 5'-monophosphate (AMP) or bradykinin might be more specific marker; o f a therapeutic responses to anti-inflammatory treatment than a test o f direct responsiveness to agents such as methacholine. In children se lected from the community on the basis of mildly symptomatic wheeze, w e compared in a randomized, double-blind study design the effect of 40 0 mu g/day of beclomethasone dipropionate (BDP) or placebo on three se parate ways of provoking bronchial responsiveness, using methacholine, bradykinin, and AMP as the provoking agents. Following pretreatment b ronchial challenges, 29 children received paired monthly methacholine and AMP challenges for 3 months, while for the same period another 33 children received paired monthly methacholine and bradykinin challenge s. Compared with placebo-treated subjects, FEV1 increased significantl y in the children receiving BDP. This improvement was observed in thos e randomized to either the AMP challenge or the bradykinin challenge. In children challenged with AMP, the PD20 AMP increased significantly after 1 month and 2 months of BDP therapy when compared with placebo, while under similar conditions the PD20 methacholine was not significa ntly affected. In children challenged with bradykinin, BDP therapy did not significantly alter either the PD20 bradykinin or PD20 methacholi ne. We conclude that a bronchial challenge with AMP appears to be a mo re sensitive predictor of response to anti-inflammatory treatment than either methacholine or bradykinin. (C) 1997 Wiley-Liss, Inc.