THE DIFFERENTIAL RELEASE OF EOSINOPHIL GRANULE PROTEINS - STUDIES ON PATIENTS WITH ACUTE BACTERIAL AND VIRAL-INFECTIONS

Background Earlier in vitro studies have suggested that the eosinophil may release its granule proteins selectively depending on the stimulu s to which the cell is exposed. Objective The object of the present st udy was to study the question of selective release in vivo by means of serum measurements of the two eosinophil granule proteins eosinophil cationic protein (ECP) and eosinophil peroxidase (EPO) in acute infect ions. Methods Fourty-six subjects with acute infections were studied b efore treatment, 20 with bacterial infections and 26 with viral infect ions. Serum ECP, EPO and MPO were measured by specific RIA. Results In acute bacterial infections ECP, but not EPO, was significantly raised in serum (P < 0.0001) compared with non-infected healthy subjects. In acute bacterial infections ECP was significantly correlated to the le vels of the neutrophil marker myeloperoxidase (MPO) (r(s) = 0.96, P < 0.0001) but not to EPO. In acute viral infections neither ECP nor EPO were on average raised. However, almost 20% the patients had elevated levels of both proteins. In the viral infections the serum-levels of E CP and EPO were correlated (r(s) = 0.63, P < 0.001), but no correlatio n was found with MPO. Conclusion It is concluded that eosinophils are activated during acute bacterial infections and that this activation r esults in the preferential mobilisation of ECP. The simultaneous assay of the two eosinophil proteins, ECP and EPO, may give new insight int o the role of the eosinophil in disease.