Recently, the roles of inflammatory processes in the pathogenesis of asthma have been emphasized. To elucidate the roles of T lymphocytes in local inflammatory sites in asthma, we examined T cell phenotypes with flow cytometry and carried out cytokine message amplification phenotyping (MAPPing) of bronchoalveolar lavage (BAL) cells taken from patients with steady-state asthma (n = 11). The percentage of CD4+ T cells in total lymphocytes correlated significantly (r = 0.784, p < 0.005) with that of lymphocytes in total CD45+ BAL cells. The positivities of T cell activation markers (CD25, HLA-DR) in CD4+ T cells were inversely correlated with the ratio of CD3+ T cells to total CD45+ BAL cells (CD25, r = 0.648, p = -0.059, HLA-DR, r = -0.741, p < 0.05). Most CD4+ T cells were of the CD45 RO+ "memory" phenotype. With cytokine MAPPing, IL-2 or IFN gamma were detected in only 2 of 11 patients, but IL4 or IL-5 were detected in 8 patients. These results suggest that non-activated TH2 type memory CD4+ T cells accumulate in local inflammatory sites of the bronchi of patients with steady-state asthma, and that these cells releases cytokines (IL-4, IL-5) when activated by some stimuli, which can lead to an asthma attack.
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