THE ROLE OF ATOPY IN GRAIN DUST-INDUCED AIRWAY DISEASE

To determine whether atopy influences the physiologic or inflammatory response to grain dust, we compared spirometric measures of airflow an d bronchoalveolar lavage (BAL) measures of lower respiratory tract inf lammation between demographically similar nonatopic (n = 10) and atopi c (n = 10) study subjects after each of two inhalation exposures: Hank s' balanced salt solution (HBSS) and corn dust extract (CDE; 0.4 mu g of endotoxin/kg body weight). Subjects were healthy nonsmokers with si milar baseline pulmonary function, without bronchial hyperreactivity, and had not participated in agriculture. Atopic subjects had two or mo re positive skin responses to 30 common environmental allergens. Both groups developed significant airflow obstruction and lower airway infl ammation after CDE inhalation. Importantly, the magnitude of the post- CDE exposure airflow decrements, BAL cellularity, and BAL concentratio n of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), IL-6, and IL-8 did not significantly differ between atopics an d nonatopics. The concentrations of histamine and eosinophils in the B AL fluid were unaffected by CDE inhalation and did not significantly d iffer between atopics and nonatopics. Atopic status does not appear to be a significant determinant of airflow obstruction or lower airway i nflammation following CDE inhalation. Our findings suggest that atopy may play, at most, a minor role in the development of grain dust-induc ed airway disease.