Inflammatory and mechanical factors of allergen-induced bronchoconstriction in mild asthma and rhinitis

We studied whether different bronchial responses to allergen in asthma and rhinitis are associated with different bronchial inflammation and remodelin g or airway mechanics. Nine subjects with mild asthma and eight with rhinit is alone underwent methacholine and allergen inhalation challenges. The lat ter was preceded and followed by bronchoalveolar lavage and bronchial biops y. The response to methacholine was positive in all asthmatic but in only t wo rhinitic subjects. The response to allergen was positive in all asthmati c and most, i.e., five, rhinitic subjects. No significant differences betwe en groups were found in airway inflammatory cells or basement membrane thic kness either at baseline or after allergen. The ability of deep inhalation to dilate methacholine-constricted airways was greater in rhinitis than in asthma, but it was progressively reduced in rhinitis during allergen challe nge. We conclude that 1) rhinitic subjects may develop similar airway infla mmation and remodeling as the asthmatic subjects do and 2) the difference i n bronchial response to allergen between asthma and rhinitis is associated with different airway mechanics.