[Activation status of eosinophils in the bronchial mucosa in symptomatic and asymptomatic asthmatics]

Although eosinophils are generally thought to play a central role in the pathogenesis of asthma, there is a few evidence not to support this view. In order further to test this hypothesis, we studied whether the magnitude of eosinophil infiltration in the bronchial mucosa and their activation status are related to clinical manifestations. Bronchial biopsies were obtained from 15 symptomatic asthmatics, 17 asymptomatic asthmatics, 11 patients with asthma who had been taking oral prednisolone for at least 1 month, and 16 controls, then stained immunohistochemically with a EG2 monoclonal antibody. The serial sections were stained with Hansel. In 15 subjects, criostal sections were immunostained with anti CD3, CD4, CD8 and CD25 antibodies. There was a significant increase in the numbers of Hansel staining-positive cells, EG2 positive cells and % of EG2 positive cells in symptomatic asthmatics. There was a significant positive correlation between the numbers of Hansel-staining positive cells and CD3, CD4 and CD25 positive cells, and between the numbers of EG2 positive cells and CD4, CD25 positive cells. These results confirm the hypothesis that eosinophils play a key role in the pathogenesis of asthma, and T cells are controller cells in the recruitment and activation of eosinophils.