PULMONARY INFLAMMATION AFTER SEGMENTAL RAGWEED CHALLENGE IN ALLERGIC ASTHMATIC AND NONASTHMATIC SUBJECTS

Inflammatory reactions in the airways are thought to play an important role in asthma pathogenesis. The goal of this work was to test prospectively the hypothesis that the pulmonary inflammatory response to segmental antigen challenge is greater in allergic asthmatic (AA) subjects than in allergic nonasthmatic (ANA) subjects. A total of 46 ragweed-allergic subjects, 27 AA and 19 ANA, took part in these studies. Subjects had normal or nearly normal pulmonary function, were on no chronic medication, and were characterized as to their skin sensitivity to intradermal ragweed injection, their nonspecific responsiveness to methacholine, and the presence (or absence) of a late asthmatic response after whole-lung antigen challenge. Subjects then underwent bronchoscopy, bronchoalveolar lavage (BAL) of a control lung segment, antigen lung challenge of a contralateral lung segment with 5 ml of a concentration of ragweed solution 100-fold higher than that required to produce a positive skin reaction, and finally, BAL of the challenged segment after 24 h. AA did not differ from ANA in any inflammatory parameter measured in BAL fluid (total cells/ml, macrophages/ml, lymphocytes/ml, eosinophils/ml, neutrophils/ml, total protein, albumin, urea, or eosinophil cationic protein) 24 h after challenge. In addition, there was no relationship between nonspecific bronchial responsiveness to methacholine and eosinophils recruited to the lung by segmental antigen challenge. Rather, in both groups a marked inflammatory response was seen only in the subgroup of subjects who demonstrated a late airway reaction after whole-lung antigen challenge, regardless of disease classification. We conclude that basic aspects of the pulmonary inflammatory response induced by segmental antigen challenge 24 h after challenge are the same in AA and ANA and that the more important predictive factor is the presence of a late asthmatic response after whole-lung challenge.