Comparison of Bronchodilator Responsiveness After Methacholine-induced and AMP-induced Bronchoconstriciton in Asthmatic Children

Abstract

RATIONALE: Airway Hyperresponsivness (AHR) and airway obstruction, relieved by bronchodilators are one of the main characteristics of asthma. We aimed to evaluate bronchodilator responsiveness (BDR) by applying a short-acting β-agonist (SABA) after methacholine- and adenosine 5'-monophosphate (AMP)-induced bronchoconstriction, respectively.METHODS: Methacholine and AMP challenges were performed with 3 days of interval in 69 children with mild persistent to moderate asthma. They were followed up at the Allergy Clinic of Korea University Anam Hospital. Each provocation test was terminated when the FEV1 decreased by more than 20% of its baseline value. Fifteen minutes after SABA inhalation in the state of bronchoconstriction, BDR was evaluated by measuring the FEV1. Each subject was evaluated by serum total IgE, blood eosinophil counts and serum eosinophil cationic protein (ECP).RESULTS: BDR after methacholine challenge (30.7±18.0%) and AMP challenge (35.2±24.0%) showed no significant differences. BDR after AMP challenge showed a significant correlation with the serum total IgE, and blood eosinophil counts, and serum ECP, but not in the methacholine challenge.CONCLUSIONS: In asthmatic children, BDR after each methacholine and AMP provocation tests showed no differences. However, BDR after AMP challenge test showed a significant correlation with total IgE and blood eosinophilic inflammatory markers, compared to BDR after methacholine challenge test. RATIONALE: Airway Hyperresponsivness (AHR) and airway obstruction, relieved by bronchodilators are one of the main characteristics of asthma. We aimed to evaluate bronchodilator responsiveness (BDR) by applying a short-acting β-agonist (SABA) after methacholine- and adenosine 5'-monophosphate (AMP)-induced bronchoconstriction, respectively. METHODS: Methacholine and AMP challenges were performed with 3 days of interval in 69 children with mild persistent to moderate asthma. They were followed up at the Allergy Clinic of Korea University Anam Hospital. Each provocation test was terminated when the FEV1 decreased by more than 20% of its baseline value. Fifteen minutes after SABA inhalation in the state of bronchoconstriction, BDR was evaluated by measuring the FEV1. Each subject was evaluated by serum total IgE, blood eosinophil counts and serum eosinophil cationic protein (ECP). RESULTS: BDR after methacholine challenge (30.7±18.0%) and AMP challenge (35.2±24.0%) showed no significant differences. BDR after AMP challenge showed a significant correlation with the serum total IgE, and blood eosinophil counts, and serum ECP, but not in the methacholine challenge. CONCLUSIONS: In asthmatic children, BDR after each methacholine and AMP provocation tests showed no differences. However, BDR after AMP challenge test showed a significant correlation with total IgE and blood eosinophilic inflammatory markers, compared to BDR after methacholine challenge test.