기관지 천식의 기도과민 반응과 기관지폐포세척액 소견 = The Relationship between Bronchoalveolar Lavage Findings and Bronchial Hyperresponsiveness in Stable Asthma

다국어 초록 (Multilingual Abstract)

Objectives: Chronic asthma has a number of characteristic feature: the increased airway responsiveness and the development of bronchial inflammation. Although mechanism of airway inflammation in bronchial asthma is not clear, activated T cell has an important role in migration and activation of inflammatory cells through secretion of lymphokine. Oxygen radicals produced by air-space cells are is increased in symptomatic asthma in relation to clinical disease activity. With this background, we examined whether lymphocyte subsets and oxygen radicals released from alveolar macrophage are increased in asthmatic subjects compared with controls, and are correlated with degree of bronchial inflammation or bronchial hyperresponsiveness in asthmatic subject. Method: 22 stable asthmatics and 8 healthy controls were participated in this study and stable asthmatics were divided into 3 group according to PC20 for methacholine: mild, moderate, and severe. We performed flow-cytomatry analysis of lymphocytes obtained from bronchoalveolar lavage (BAL) fluid and peripheral blood. The oxygen radicals released from alveolar macrophage was measured after either stimulated with phorbol myristate acetate (PMA) or non-stimulated states. Superoxide anion production were measured by spectrophotometeric assay using the principle of superoxide dismutase inhibitable cytochrome-C reduction. Total oxygen free radicals were measured by chemiluminescence using lucigenin. Results: 1) Total cell counts and composition of eosinophil significantly increased in patient with bronchial asthma compared with healthy controls (p<0.01). Of lymphocyte, composition of CD8+ cell significantly increased in patients with bronchial asthma (p<0.01). 2) There were no difference in composition of lymphocyte subset in peripheral blood between patients with bronchial asthma and controls (p>0.05). 3) The composition of CD4+ cell significantly increased in moderate and severe groups compared with mild group (p<0.05), whereas the composition of CD8+ cell were not different among 3 groups (p>0.05). 4) Superoxide anion and total oxygen radicals released from alveolar macrophage significantly increased in patients with bronchial asthma compared with controls (p<0.05). In moderate group, superoxide anion and total oxygen radicals released from alveolar macrophage was higher than controls when alveolar macrophage was stimulated with PMA (p<0.05). In severe group, they was higher than controls irrespective of PMA-stimulation (respectively, p<0.01, p<0.05). 5) There were correlation between superoxide anion released from alveolar macrophage after stimulation with PMA and composition of eosinophil in BAL fluid (p<0.05, r=0.47). Conclusion: This study incriminates a role for T cell (esp, CD4+, CD8+ cell) and reactive oxygen radicals released from alveolar macrophage in the development of bronchial asthma.