Background: Asthma symptoms include wheezing, coughing, dyspnea, and chest tightness, as well as variable degrees of airway blockage and hyper-responsiveness. Many biomarkers have been widely studied in asthmatic children for asthma diagnosis and monitoring. Clinical decisions related to asthma control status have traditionally been based on subjective symptoms, rescue medication use, and lung function changes. Biomarkers for reflecting asthma control status remain controversial. Although a standard definition of eosinophilic asthma has not been developed yet, peripheral blood eosinophil counts of ≥150 cells/µL, ≥300 cells/µL, or ≥400 cells/µL have been used in trials on adult populations to describe eosinophilic asthma and can readily be identified in a primary care setting. Specific biomarkers of eosinophilic asthma in children have been widely used, including blood eosinophil count, sputum eosinophil count (%), fractional excretion of nitric oxide (FeNO), and serum periostin level. One of the emerging biomarkers is Eosinophil-derived neurotoxin (EDN), which is a degranulated eosinophil protein. Bronchoconstriction and hyper-responsiveness are more closely associated with the presence of eosinophil-derived neurotoxic and the eosinophil-cationic protein (ECP) in the inflamed airways.
Aim of the work: To assess Serum EDN levels as a potential biomarker for the detection of asthma control status in children as well as to distinguish asthmatic from those healthy non allergic children.
Subjects& methods: this is a cross sectional study carried out on 62 asthmatic children who are on regular follow-up at Pediatric Allergy Outpatient Clinics, Al-Azhar university Hospitals (Al-Hussein & Sayed-Galal Hospitals). The study was conducted between August 2021 and March 2022. Serum EDN concentrations were measured using an enzyme-linked immunosorbent assay (ELISA) kit, with results expressed in nanograms per milliliter (ng/ mL).
Results: There was a highly significant value of serum EDN in discrimination between asthmatic and healthy non allergic children with a sensitivity of 91.94 % and specificity of 96.67% at cutoff point is 55 ng/ml. there was a prognostic performance value of eosinophil derived neurotoxin in discrimination between uncontrolled and controlled asthmatic children with a sensitivity of 75.0% and specificity of 56.67% when the cutoff point is 75 ng/ml.
Conclusion: Serum EDN may be used as helpful biomarker beside clinical assessment to distinguish between asthmatic children from healthy non allergic children .also can be used as marker for discrimination of control status in asthmatic children and monitoring controller drugs.