AIRWAY EOSINOPHILIA IN CHRONIC-BRONCHITIS DURING EXACERBATIONS

To examine the nature and the degree of airway inflammation in chronic bronchitis during exacerbations, bronchial biopsies and sputum were o btained in 11 subjects with chronic bronchitis examined during an exac erbation, and in 12 subjects with chronic bronchitis examined under ba seline conditions. All subjects were nonatopic. Lobar bronchial biopsi es were assessed using histochemical and immunohistochemical technique s, and sputum was examined for differential cell counts of leukocytes. Subjects with bronchitis during exacerbations had, on average, 30-fol d more eosinophils in their bronchial biopsies than did those examined under baseline conditions (p < 0.001). Although to a lesser extent, t he numbers of neutrophils (p < 0.01), T-lymphocytes (CD3) (p < 0.05), VLA-l-positive cells (p < 0.01), and TNF-alpha positive cells (p < 0.0 5) were also increased during exacerbations. By contrast, the T-lympho cyte subpopulations (CD4 and CD8) and the numbers of macrophages, mast cells, IL-2R-positive cells, and IL-1beta-positive cells were similar in the two groups of subjects, as well as the percentages of ICAM-1- and E-selectin-positive vessels. Eosinophils were also increased in sp utum of subjects with exacerbations when compared with those examined under baseline conditions (p < 0.05). In conclusion, exacerbations of chronic bronchitis are associated with a marked airway eosinophilia an d with a milder increase in the number of neutrophils, activated T-lym phocytes, and TNF-alpha-positive cells in the bronchial mucosa.