Serum levels of eosinophil cationic protein and eosinophils in asthmatic children during a course of prednisolone therapy.

Eosinophils play an important role in the inflammatory events of allergic asthma. Serum eosinophil cationic protein (ECP) is a marker of disease activity and of treatment efficacy in bronchial asthma. To understand the role of ECP concentrations in disease activity of acute asthma, we determined changes in serum concentrations of ECP elaborated by activated eosinophil before and after prednisolone therapy. Circulating levels of ECP in 15 normal control subjects, and in sera of 20 asthmatic children who were allergic to house dust mites, were measured during an acute exacerbation and when the children were in stable condition, using commercially available assay kits. The mean concentrations of serum ECP were significantly higher during an acute asthma exacerbation than when the children were stable (26.41 +/- 21.66 microg/L vs 15.74 +/- 11.36 microg/L P < 0.01) or when compared to control subjects (7.50 +/- 1.42 microg/L; P < 0.001). The mean eosinophil counts (EC) during acute asthma attacks (575 +/- 286/mm3) and when stable (467 +/- 204/mm3) were higher than in the control group (181 +/- 164/mm3). The differences were statistically significant among the three groups (P < 0.05). A significant correlation was found between serum levels of ECP and EC (r = 0.788, P = 0.001) in asthmatic children; there were also significant correlations between ECP and EC in nonallergic normal control subjects (r = 0.662; P = 0.007). In conclusion, this study provides further evidence that changes in serum ECP may serve as an objective indicator for clinical activity and results of treatment in allergic asthmatics.