Clinical utility of serum levels of eosinophil cationic protein (ECP) for monitoring and predicting clinical course in childhood asthma.

Abstract

The concentration of ECP in serum has been proposed as a marker of airway inflammation in asthma. However, its clinical significance is still to be determined. This study was performed to determine whether concentration of ECP in serum reflects clinical status in asthma and can serve as a predictive parameter. Cross-sectional analysis was performed in 28 children with asthma. A total of 91 blood samples was obtained to determine levels of ECP in serum and eosinophil counts. Forced expiratory volume in 1 s was also determined at the time of the sampling. Data were analysed on the basis of asthma symptoms in the 4 weeks before and the 4 weeks after sampling. Serum levels of ECP were significantly lower in patients who had been asymptomatic for 3 or 4 weeks before sampling than in patients who had been symptomatic or asymptomatic for only 1 or 2 weeks. In the former group, serum levels of ECP were higher when patients became symptomatic after sampling than when they remained stable, a finding that suggests that serum levels of ECP may have a predictive value in certain situations. Although the concentration of ECP in serum was not proved to be predictive in the latter symptomatic group, the concentration of ECP was significantly lower when measured again 4 weeks later when the patients' symptoms had resolved. In contrast, levels of ECP were unchanged when patients remained symptomatic, a finding that suggests serum levels of ECP may reflect the clinical response to therapy. Serum ECP may be a useful marker for monitoring and predicting the clinical course in asthma.