Ratio of eosinophil cationic protein/eosinophil count as a new marker in children with acute asthma.

BACKGROUND: It is a matter of concern whether serum eosinophil cationic protein (ECP) can be considered as a disease marker in children with acute asthma being treated without corticosteroids. METHODS: Fourteen children (nine male, five female, aged 6-12 years) with acute asthmatic exacerbation, administered the appropriate drugs, with the exception of systemic or inhaled corticosteroids, were examined. They were all free from apparent asthmatic attacks during a follow-up period of 1 month. Serum ECP, eosinophil count and forced expiratory volume in 1 s (FEV1) were measured at referral, on the day of discharge, 1 week and 4 weeks after discharge, respectively. RESULTS: The ratio of ECP/eosinophil count (ECP:Eo ratio), expressed as micrograms of ECP (microgram/L)/the number of eosinophil (/microL) x 1000, was also evaluated as a marker of eosinophil activation. Compared with the value at referral, FEV1 (% predicted) significantly increased on the day of discharge (P < 0.05), 1 week after (P < 0.05) and 4 weeks after discharge (P < 0.05). However, serum ECP concentrations showed no significant changes during the follow-up period. Eosinophil count showed no significant changes on the day of discharge or 1 week after discharge, but significantly increased 4 weeks after discharge (P < 0.05). In contrast, the ECP:Eo ratio significantly decreased on the day of discharge (P < 0.05), 1 week after (P < 0.05) and 4 weeks after discharge (P < 0.05). CONCLUSION: These data suggest that serum ECP is a poor disease marker in asthmatic children with acute exacerbation who receive no corticosteroid therapy, probably due to marked changes in the eosinophil count. However, the ECP:Eo ratio might be a better marker than serum ECP in such patients.