Urine eosinophil‐derived neurotoxin: A potential marker of activity in select eosinophilic disorders

Abstract

Background: Biomarkers of eosinophilic disease activity, especially in the context of novel therapies that reduce blood eosinophil counts, are an unmet need. Absolute eosinophil count (AEC) does not accurately reflect tissue eosinophilia or eosinophil activation. Therefore, the aims of this study were to compare the reliability of plasma and urine eosinophil major basic protein 1, eosinophil cationic protein, eosinophilderived neurotoxin (EDN), and eosinophil peroxidase measurement and to evaluate the usefulness of eosinophil granule protein (EGP) measurement for the assessment of disease activity in patients with eosinophil-associated diseases treated with mepolizumab, benralizumab, or dexpramipexole.

Eosinophils from A to Z

“…111,117 Furthermore, the measurement of biomarkers such as EDN in the urine is proposed as a non-invasive method and is unaffected by cellular lysis. 117 • Galectin-10 (Gal-10), also known as Charcot-Leyden crystal (CLC) protein, is found in the sputum, nasal secretions, nasal polyps, serum, and skin tissue. 121 The presence of Gal-10 at the above-mentioned sites is indicative of asthma, EoE, rhinitis, sinusitis, AD, and EGPA in regard to diagnosis, disease activity, and treatment effectiveness.…”

“…110 • EDN can be measured in serum, sputum, bronchoalveolar lavage fluid, nasal lavage fluid, and urine. 116,117 EDN contributes as a biomarker to the diagnosis of asthma and allergic rhinitis, as well as to assess the severity of the diseases. 116,118,119 For instance, increased EDN levels are associated with respiratory syncytial virus (RSV) infection, asthma, chronic rhinosinusitis, and HES.…”

“…119 Moreover, EDN in urine has been proposed as a biomarker for asthma and AD, as well as in patients with HES and EGPA. 111,117 Furthermore, the measurement of biomarkers such as EDN in the urine is proposed as a non-invasive method and is unaffected by cellular lysis. 117 • Galectin-10 (Gal-10), also known as Charcot-Leyden crystal (CLC) protein, is found in the sputum, nasal secretions, nasal polyps, serum, and skin tissue.…”

“…It is important to note that asthmatic patients with a smoking history have a significant increase in sputum ECP levels 110 EDN can be measured in serum, sputum, bronchoalveolar lavage fluid, nasal lavage fluid, and urine 116,117 . EDN contributes as a biomarker to the diagnosis of asthma and allergic rhinitis, as well as to assess the severity of the diseases 116,118,119 .…”

“…In contrast to ECP, EDN has been proposed to be a more accurate biomarker as its levels are not affected by smoking or circadian rhythm 119 . Moreover, EDN in urine has been proposed as a biomarker for asthma and AD, as well as in patients with HES and EGPA 111,117 . Furthermore, the measurement of biomarkers such as EDN in the urine is proposed as a non‐invasive method and is unaffected by cellular lysis 117 …”