Eosinophil activation in acute asthma attacks evaluated by electronmicroscopic findings of eosinophils and the concentration of eosinophil cationic protein in sputum]

We evaluated the activation of eosinophils in the airways of patients with acute asthma attacks by measuring the concentration of sputum eosinophil cationic protein (ECP) and changes in the electron densities of the eosinophil specific granules in sputum. In six hospitalized patients with asthmatic attacks, sputum samples were collected for seven consecutive days after admission and were used for the evaluation of eosinophil activation. The concentration of sputum ECP, the incidence of changes in the electron densities of eosinophil specific granules and the severity of asthma attacks were highest on the day of admission and decreased in association with each other after treatment. A significant correlation was found between the concentration of sputum ECP and the incidence of changes in the electron densities of eosinophil specific granules. These findings suggest that the eosinophils in the airways are markedly activated and degranulated in asthma attacks.