American Journal of Respiratory and Critical Care Medicine

In order to determine whether the airway inflammatory cells of chronic obstructive pulmonary disease (COPD) are different from those seen in asthma, we have studied a subepithelial zone, 100 microns deep to the epithelial reticular basement membrane in bronchial biopsies taken from five normal nonsmoking subjects without chronic bronchitis or asthma (FEV1 percentage of predicted [mean +/- SD] 105.7 +/- 25.3), 11 subjects with chronic bronchitis alone (FEV1 percentage of predicted 98.5 +/- 12.9), and 13 subjects with chronic bronchitis in whom there was also evidence of airflow limitation (i.e., COPD; FEV1 percentage of predicted 59.7 +/- 10.0). Using immunohistochemical markers, we counted distinct types of inflammatory cell and expressed them as [median and range] per mm basement membrane. When there was airflow limitation we found significantly increased numbers of CD3+ T lymphocytes (COPD 22.3 [2.6 to 68.2] versus normal 3.7 [1.5 to 16.3]; p < 0.05), an increased number of CD8+ cells (COPD 19.3 [1.8 to 45.5] versus normal 2.3 [0.9 to 4.2]; p < 0.01), and increased expression of HLA-DR (COPD versus normal; p = 0.01). There was also an increased number of CD68+ cells (i.e., macrophages) (COPD 7.4 [0.4 to 16.9] versus normal 0.7 [0 to 2.6]; p < 0.01; COPD versus chronic bronchitis alone 2.7 [0 to 12.8]; p < 0.05). There were no significant differences between the groups in the numbers of subepithelial neutrophils, mast cells, eosinophils or B lymphocytes. There were weak but significant negative associations between the CD8+ T-cell subset (r = -0.42), neutrophils (r = -0.46), and eosinophils (r = -0.53) and FEV1 percentage of predicted in all the chronic bronchitic smokers (p < 0.05). The data confirm the involvement of subepithelial T lymphocytes and macrophages in smoking-induced airflow limitation and provide novel data which support the view that COPD is distinct from asthma with respect to the predominance of the CD8+ T-cell subset in this smoking-related condition.


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American Journal of Respiratory and Critical Care Medicine

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