This study sought to evaluate the use of serum
eosinophil-derived neurotoxin (EDN), which has been proposed as a marker of airway
inflammation in
asthma in the diagnosis and evaluation of the severity and bronchial hyperresponsiveness in childhood
asthma. We studied 72 children with atopic
asthma, 36 children with nonatopic
asthma, and 43 healthy controls. Skin prick tests, pulmonary function tests, and
methacholine challenge tests were performed, in addition to total eosinophil count, serum ECP, and EDN being measured in all subjects. EDN levels were significantly higher in the atopic
asthma group than those in the nonatopic
asthma group or control group (p < 0.001), as were ECP levels (p < 0.001). EDN levels differed more significantly among groups divided by
asthma severity (p < 0.001) than did ECP levels for these groups (p < 0.05). For the groups divided according to bronchial hyperresponsiveness, both EDN and ECP levels were significantly different (p < 0.005 and p < 0.01, respectively). Significant correlations were found between EDN and PC(20) (gamma = -0.281; p < 0.001), between ECP and PC(20) (gamma = -0.274; p < 0.005), and between EDN and ECP (gamma = 0.443; p < 0.001). In conclusion, serum EDN, as another marker of eosinophilic
inflammation together with ECP, may aid in the diagnosis of
asthma, especially atopic
asthma, and in the evaluation of the severity and bronchial hyperresponsiveness in childhood
asthma.