The asthmatic airway response to inhaled antigen

The airway response to inhaled antigen was measured in asthmatic patients at 5, 10 ad 20 minutes following bronchial challenges. The over-all frequency of positive responses in the 26 individual challenges was 27%. There were no significant differences between the 5-, 10- or 20-minute responses. Patients with positive responses to bronchial challenge manifested high grade skin reactivity by intradermal tests. Positive responses to bronchial challenge occurred only at 1 X 10(-3) weight/volume (w/v) concentration of inhaled antigen. Although the degree of methacholine reactivity was related to positive antigen challenge, two subjects with a positive challenge had minimal methacholine reactivity.