AIRWAY RESPONSES TO ANTIGEN CHALLENGE IN ALLERGIC RHINITIS AND ALLERGIC-ASTHMA

[摘要] The density dependence of the maximum expiratory flow-volume curve, functional residual capacity (FRC) and specific airway conductance (SGaw) were determined before and during bronchial provocaton with ragweed extract in 27 subjects with ragweed hypersensitivity and a history of bronchial asthma (16 subjects) or allergic rhinitis (11 subjects). Mean baseline SGaw was significantly lower while mean volume of isoflow (Visov) and FRC were signficantly higher in subjects with bronchial asthma. During antigen challenge, 10 of 16 subjects with bronchial asthma (63%) and 5 of 11 subjects with allergic rhinitis (45%) showed a greater than 35% decrease in SGaw (reactors); mean relative decreases in SGaw from baseline were 46% and 53%, respectively. The remaining subjects showed a less than 35% decrease in SGaw (nonreactors) with mean relative decreases of 9% (allergic asthma) and 6% (allergic rhinitis). Mean Visov increased in all subjects with bronchial asthma and in 8 of 11 subjects with allergic rhinitis. A significant increase in FRC (6%) was seen only in the reactors with bronchial asthma. Following antigen challenge, the .beta.-adrenergic agonist, isoetharine, increased SGaw and decreased Visov. In asymptomatic subjects with ragweed hypersensitivity, central and peripheral airway function is more abnormal in subjects with bronchial asthma than in subjects with allergic rhinitis; subjects of both groups show quantitatively and qualitatively comparable airway responses during antigen challenge with a decrease in SGaw or an increase in Visov, possibly representing an increase in central and/or peripheral airflow resistance, respectively; Visov may be a more sensitive indicator of airway response to antigen challenge from SGaw; and the bronchodilator effects of a .beta.-adrenergic agonist on antigen-induced bronchospasm are similar in both groups.