Changes in serum eotaxin and eosinophil cationic protein levels, and eosinophil count during treatment of childhood asthma.

BACKGROUND AND PURPOSE Increased serum levels of eotaxin are related to the severity of asthma in adults. There are limited data on the effects of oral corticosteroids and inhaled corticosteroid therapy on serum levels of eotaxin and eosinophil cationic protein (ECP) and peripheral blood eosinophil counts (ECs) in pediatric asthma patients. We investigated prospectively the changes in eotaxin and ECP serum levels and peripheral blood ECs after administering oral corticosteroids and then inhaled corticosteroids plus long-acting beta2 agonist treatment in pediatric patients. METHODS Serum samples of 20 pediatric patients with mild-to-moderate asthma were collected before treatment, after 5-7 days of oral prednisolone treatment, and after 1-2 months of inhaled fluticasone plus salmeterol treatment. Peak expiratory flow was used as the outcome index. RESULTS Serum eotaxin levels remained the same after oral prednisolone treatment, but decreased after subsequent inhalation treatment compared with the end of oral steroid treatment (64.7 +/- 22.6 vs 85.7 +/- 36.8 pg/mL, p<0.001). The EC and serum ECP levels declined soon after oral steroid treatment, rebounding to initial levels during inhalation treatment. The decrease in ECP level was positively correlated with the decrease in ECs with oral steroid treatment (r(2) = 0.28, p=0.016). There was no correlation between changes in eotaxin levels and peak expiratory flow. CONCLUSIONS Our data suggest that the serum eotaxin level, not peripheral blood EC or serum ECP level, declines during inhaled fluticasone plus salmeterol treatment and might serve as a surrogate marker of T helper 2 residual activity in pediatric asthma.