24-HOUR TIME-COURSE OF EOSINOPHIL GRANULE PROTEINS ECP AND EPX DURINGBRONCHIAL ALLERGEN CHALLENGES IN SERUM OF ASTHMATIC-CHILDREN

To study in vivo monitoring variables for bronchial allergen challenge s, we investigated the time course of the eosinophil granule proteins, eosinophil cationic protein (ECP) and eosinophil protein X (EPX) afte r allergen provocation in serum. Thirty-two asthmatic children sensiti ve to house-dust mites and six healthy young adult controls were chall enged by bronchial allergen provocations with Dermatophagoides pterony ssinus and D. farinae. Blood samples were taken at regular intervals u p to 24 h. Base-line concentrations of ECP (P < 0.004), EPX (P < 0.002 ), and eosinophils (P < 0.001) were found to be increased in asthmatic children, as compared with healthy controls. ECP and EPX concentratio ns showed a uniform pattern with two characteristic features: 1) a rap id increase for both mediators up to 30 min after provocation over bas e-line values (P < 0.0001 and P < 0.001), followed by a rapid decrease nearly to base-line values in the next 30 min; and 2) a steady increa se for ECP and EPX up to 10 h (P < 0.02 and P < 0.01). and even higher levels at 24 h, after challenge (P < 0.002 and P < 0.003). We conclud e that although eosinophils are activated in asthmatic children after bronchial allergen challenge, ECP and EPX concentrations are not suita ble monitoring variables. Base-line eosinophils seem to predict the oc currence of a late-phase asthmatic reaction after allergen provocation .