Comparison of Serum Eosinophil-Derived Neurotoxin Levels between Wheezing and Non-wheezing Groups in Children with Respiratory Tract Infections

RATIONALE: Eosinophil-derived neurotoxin (EDN) is associated with recurrent wheezing episodes after bronchiolitis, childhood asthma, and allergic rhinitis. We investigated if there is a measurable difference between serum EDN levels in children with wheezing and non-wheezing respiratory infections.

METHODS: 171 children who visited a University Hospital with respiratory infections were enrolled in the study. We divided the children into two groups, which were wheezing (n=46) and non-wheezing (n=125), and compared the levels of serum EDN in these two groups.

RESULTS: The level of serum EDN in the wheezing group was significantly higher than the level of serum EDN in the non-wheezing group (P<0.001). We divided the non-wheezing group into three sub-groups: pneumonia, common cold, and tonsillitis. The level of serum EDN in the wheezing group was significantly higher than the level of serum EDN in the pneumonia, the common cold, and the tonsillitis groups (P<0.001). There was no significant difference in the levels of serum EDN among the pneumonia, common cold, and tonsillitis groups.

CONCLUSIONS: These findings suggest that elevated serum EDN levels could be one of the distinctive features of respiratory infections with wheezing.