Relationship of blood EG2+ eosinophils in patients with bronchial asthma.

The presence of eosinophils in peripheral blood has been previously associated with different degrees of activity in the evolution of disease in asthmatics. The eosinophil cationic protein is a mediator released by the eosinophils when they are activated due to various stimuli. The monoclonal antibody EG2 binds to human ECP, the epitopes which EG2 recognizes is only present in the secreted form of ECP, hence it only stains eosinophils which are undergoing activation and/or secretion. Flow cytometry was used to measure the level of eosinophils stained by the monoclonal antibody EG2 (eosinophil EG2+) in the peripheral blood of subjects with unstable extrinsic bronchial asthma, stable extrinsic bronchial asthma and healthy control group. A statistically significant higher level of eosinophil EG2+ was found in the group with unstable asthma than in either the group with stable asthma or the group of healthy subjects (p < 0.0002). No difference was found between the patients with stable asthma and the control group. The level of eosinophil EG2+ in peripheral blood, measured by flow cytometry, could be used as an indicator of inflammatory activity in patients suffering from bronchial asthma.