Comparison of Methacholine and Adenosine 5'-Monophosphate Responsiveness Between Preschool Children with Atopic Asthma and Those with Nonatopic Asthma

Lee, Jin Hee; Lee, Ju Kyung; Suh, Dong In; Koh, Young Yull

Abstract

PURPOSE
It is well known that atopy is a major determinant of bronchial hyperresponsiveness (BHR) in both asymptomatic and asthmatic children. However, the relationship between atopy and BHR has not been well studied in preschool children with asthma. The aim of this study was to evaluate and compare BHR to direct and indirect stimuli between young children with atopic asthma and those with nonatopic asthma.
METHODS
Methacholine and adenosine 5'-monophosphate (AMP) bronchial challenges were performed on 177 preschool children with asthma (145 atopics and 32 nonatopics) using a modified auscultation method. The endpoint was defined as the appearance of wheezing and/or oxygen desaturation.
RESULTS
While the geometric mean of methacholine endpoint concentration was not significantly different between atopics and nonatopics that of the AMP endpoint concentration was significantly lower in atopics than in nonatopics (25.5 vs. 59.4 mg/mL; P=0.032). A positive response to methacholine (an end-point concentration < or =8 mg/mL) was observed in 96.5% (140/145) of patients with atopic asthma and in 84.3% (27/32) with non-atopic asthma. The frequency of a positive response to AMP (an endpoint concentration < or =200 mg/mL) was 86.8% (126/145) in patients with atopic asthma and 75% (24/32) in these with non-atopic asthma.
CONCLUSION
Atopics more frequently displayed BHR to AMP and had a higher responsiveness to AMP than nonatopics. These results suggest that atopic and non-atopic asthma in preschool children may be related to the distinctive pathophysiologic pathways.