[A basic study on the plasma and serum levels of eosinophil cationic protein (ECP) in bronchial asthma]

A basic study on the blood eosinophil cationic protein (ECP) as an index for eosinophil activation in bronchial asthma was performed. 1) ECP concentration in the serum collected 2 hours after blood sampling and the peripheral eosinophil count were significantly higher in asthmatic patients than in normal individuals. A correlation between these two parameters was observed in normal controls but not in asthmatic patients. These findings suggest that the degree of eosinophil activation, which is reflected by the blood ECP concentration, varies with the clinical condition in asthmatic patients. 2) The plasma and serum ECP levels were compared. The serum ECP was higher than the plasma ECP in both normal controls and asthmatic patients. In asthmatic patients, however, plasma ECP levels poorly correlated with serum levels: the serum levels were markedly elevated in some cases, and only the plasma levels were significantly elevated during symptomatic periods compared with stable periods. Therefore, attention must be paid not only to the serum ECP concentration, but also to the plasma ECP concentration and the plasma-serum difference. 3) This plasma-serum difference in ECP concentration may be due to the in vitro release of ECP during coagulation after blood sampling rather than the effect of alpha 1-macroglobulin concentration, because supernatants from stimulated platelets elicited ECP release from eosinophils.