Skin reactivity to inhalant allergens, total serum IgE levels, and bronchial responsiveness to methacholine are increased in parents of nonatopic asthmatic children

Background:Family studies suggest that asthma has an increased familial occ urrence, but the hypothesis of a genetic predisposition to IgE response and bronchial hyperresponsiveness (BHR) on the expression of nonatopic asthma is controversial. Objective: The aim of this study was to evaluate familial predisposition to IgE response and BHR on expression of nonatopic asthma. Methods: One hundred four parents of nonatopic asthmatic children, 154 pare nts of atopic asthmatic children, 78 parents of atopic nonasthmatic control children, and 80 parents of nonatopic control children provided questionna ire data and underwent allergy skin prick tests with 10 inhalant allergens and methacholine bronchial provocation tests. Total serum IgE levels were d etermined in 352 parents (134 with atopic asthmatic children, 87 with nonat opic asthmatic children, 65 with atopic control children, and 66 with nonat opic control children). Results: Prevalence of asthma, based on questionnaire data and on BHR to me thacholine, was higher among parents of nonatopic asthmatic children (10.6% ) and atopic asthmatic children (9.1%) than among those of nonatopic contro l children (1.3%). BHR to methacholine was higher among parents of nonatopi c asthmatic children (19.2%) and atopic asthmatic children (16.2%) than amo ng those of atopic and nonatopic control children (5.1% and 1.3%, respectiv ely). The percentage of positive skin test responses to 10 inhalant allerge ns was higher among parents of atopic asthmatic children (43.9%), nonatopic asthmatic children (39.4%), and atopic control children (38.5%) than among those of nonatopic control children (23.7%). Geometric means (IU/mL + SEM) of total serum IgE were higher among parents of atopic and nonatopic contr ol children than among those of nonatopic control children (2.11 +/- 0.05 v s 2.20 +/- 0.06 vs 2.09 +/- 0.07 vs 1.92 +/- 0.06). Conclusion: Nonatopic asthma runs in families. The prevalence of positive s kin test responses to inhalant allergens, BHR to methacholine, and total se rum IgE levels is higher among the parents of nonatopic and atopic asthmati c children than among those of nonatopic control children.