Age-dependent relationship between bronchial hyperresponsiveness to methacholine and total serum IgE level in asthmatic children

Background: A relationship between nonspecific bronchial hyperresponsivenes s and allergic airway inflammation has been reported in children and in adu lts with asthma, but the relationship in infants with asthma is still uncle ar. Objective: To evaluate the relationship between bronchial hyperresponsivene ss and total serum IgE level throughout childhood. Bronchial reactivity to methacholine from the age of 1 to 16 years was studied by methacholine inha lation challenge using transcutaneous oxygen pressure (tcPO(2)) monitoring. Methods: Two hundred one asthmatic children (boys:girls = 132:69; 7.3 +/- 4 .0 years of age, mean +/- SD) were enrolled in this study. The tcPO(2) was measured using a tcPO(2) monitor. Serial doses of methacholine were doubled until a 10% decrease in tcPO(2), from the baseline was reached. The cumula tive dose of methacholine at the inflection point of tcPO(2) was considered to represent the bronchial reactivity to methacholine. Results: There was no relationship between the cumulative dose of methachol ine at the inflection point of tcPO(2) and total serum IgE level in the gro up of children aged 1 to 4 years (P = 0.212), but significant correlations were found in the groups aged 5 to 10 years and 11 to 16 years (P = 0.044 a nd P = 0.014, respectively). Conclusions: We conclude that there is an age-dependent relationship betwee n bronchial reactivity to methacholine and the total serum IgE level and th at inhaled allergens, which were more common allergens in older children, m ay have some effects on the degree of bronchial reactivity to methacholine in children with asthma.