OBJECTIVES: Chronic asthma has a number of characteristic feature; the increased airway responsiveness and bronchial inflammation. Although these mechanisms are not clear, activated T-cell has had an important role in migration and activation of inflammatory cells. In order to evaluate the role of T-lymphocyte and T-cell subsets in the development of asthmatic symptoms and the posibility for predicting the therapeutic response, we performed bronchoalveolar lavage from asymptomatic and symptomatic asthmatic subjects and inflammatory cell count, T-cell subset, activated T-lymphocyte were analysed and they were compared with healthy controls. METHOD: 76 bronchial asthmatics and 54 healthy controls were enrolled in this study. Asthmatic patients were classified into symptomatic and asymptomatic group according to symptom severity. Symptomatic group was divided into two groups according to therapeutic response ; early responder(ER) and late responder(LR). Lymphocytes(T-lymphocytes subsets and activation marker) in bronchoalveolar lavage(BAL) cells were analyzed using a flow-cytometry. RESULTS: The counts of eosinophil and neutrophil in BAL fluid were significantly higher in both asymptomatic and symptomatic asthmatic patient than those of healthy controls (p<0.05). The number of T3, T4, and T8 lymphocytes were significantly higher in symptomatic asthmatic patient than those of healthy controls, and the counts of T3-IL2R+, T4-IL2R+, and T8-IL3R+ lymphocytes were significantly higher in symptomatic subsets than in healthy controls(p<0.05). Although there were no significant differences in the number of lymphocyte, eosinophil and neutrophil between the ER and LR of symptomatic patients(p>0.05), the numbers of T3 and T4 lymphocyte subsets were significantly higher in LR than in healthy controls, and the number of T3-IL2R+, T4-IL2R+ lymphocytes were significantly higher in ER than in healthy controls(p<0.05). CONCLUSION: We could conclude that the infiltration and activation of T-lymphocytes might be associated with the development of asthmatic symptoms and responsiveness to therapy.