Eosinophil-Derived Neurotoxin Is an Asthma Biomarker Linked to Wheezing Severity in Preschool Children

Novel biomarkers are needed for understanding the clinical characteristics of children with acute wheeze (AW) and for optimizing management strategies. This study investigated serum eosinophil-derived neurotoxin (EDN) and blood eosinophil count (B-Eos) in Japanese preschool children with current asthma (CA) and/or AW.

Two cohorts of Japanese children under 6 years of age were screened for allergy and asthma symptoms using the ISAAC questionnaire and tested for EDN, B-Eos, and specific IgE. Cohort 1 included 16 children with CA, 45 with other allergies (OA), e.g., eczema or rhinitis, and 34 healthy controls (HC). Optimal cut-offs (receiver operating characteristic analysis) for EDN and B-Eos were determined for CA vs. HC. Cohort 2 included 87 children with AW grouped according to symptom severity, high or low EDN and B-Eos (using the optimal cut-offs), and followed up during recovery.

Children with CA or OA had higher EDN vs. HC (p < 0.01). B-Eos was higher in CA vs. HC (p < 0.05). The optimal cut-offs for EDN and B-Eos were 26.5 µg/L and 235 cells/µL, respectively. EDN was higher in wheezing children with severe vs. mild or moderate symptoms (p < 0.05). Conversely, B-Eos were higher in children with mild vs. moderate AW symptoms (p < 0.01). EDN decreased in children with high EDN between acute visit and recovery (p < 0.001). High EDN, and to a lesser extent high B-Eos, were associated with IgE sensitization.

Serum EDN is a promising exploratory biomarker for CA and AW in preschool children associated with wheezing severity and recovery after treatment.