Although several biomarkers have been proposed for eosinophilic asthma, biomarkers for reflecting asthma control status remain controversial. Eosinophil-derived neurotoxin (EDN), a degranulated eosinophil protein, is an emerging biomarker in asthmatic patients.
This study analyzed serum EDN concentrations in asthmatics and compared its performance to that of blood eosinophil count as an indicator of asthma control status.
We enrolled 75 uncontrolled asthmatics, 56 controlled asthmatics, and 43 healthy controls from Asan Medical Center. Serum EDN levels (ng/mL) were measured using an enzyme-linked immunosorbent assay kit. The predictability of EDN for asthma control status was analyzed by univariate and multivariable logistic regression analyses. A receiver operating characteristic (ROC) curve analysis was conducted to compare the performances of serum EDN level and blood eosinophil count as indicators of uncontrolled asthma status.
The mean serum EDN level in the uncontrolled asthma group was higher than in the controlled asthma and healthy groups (103.2±60.2 vs. 60.8±49.7 vs. 49.6 ± 28.3 ng/mL, p<0.001). Serum EDN level was the significant parameter related to asthma control status in univariate and multivariable analysis (both p<0.001). Serum EDN levels correlated with blood eosinophil counts (r=0.510, p<0.001). However, in ROC analysis, serum EDN level showed a significantly better performance for predicting uncontrolled asthma status (area under the curve, 0.726 vs. 0.628, p=0.024).
Serum EDN levels significantly differed between patients with controlled and uncontrolled status in adult asthmatics. To our knowledge, this is the first study to identify EDN as a better indicator of asthma control status than blood eosinophil count.

Copyright © 2020. Published by Elsevier Inc.