Predictive Value of Eosinophil Cationic Protein in Nasal Secretions in Eosinophilic Chronic Rhinosinusitis

Objectives To investigate the value of secretions Eosinophilic cationic protein (ECP) detection in the diagnosis of endotypes of Chronic rhinosinusitis (CRS) and its correlation with clinical symptoms, so as to provide guidance for the clinical application of EOS and ECP detection in secretions. Methods Patients' nasal secretions and polyps (or middle turbinate for control) were collected and their EOS% and ECP levels were measured. Correlation analysis was performed for EOS% and ECP levels in secretions and tissues, respectively. The correlation between secretions EOS% and ECP and clinical symptom scores (symptomatic visual analog scale (VAS) scores, Lanza‐kennedy scores from nasal endoscopy and Lund‐Mackay scores from sinus CT) was further analyzed. Receiver operating characteristic curves were used to assess the predictive potential of EOS% and ECP in nasal secretions. Results Eosinophilic chronic rhinosinusitis (ECRS) patients had higher concentrations of ECP in nasal secretions than healthy subjects and NECRS (non‐eosinophilic CRS) ( p < 0.0001;0.0001); EOS% in nasal secretions was higher in ECRS than healthy subjects ( p = 0.0055), but the differences between ECRS and NECRS were not statistically significant ( p = 0.0999). Correlation analysis showed that tissue EOS% was correlated with ECP concentration and EOS% in nasal secretions ( R = 0.5943;0.2815). There was a correlation between EOS% in secretions with a total LM score ( R = 0.3131); ECP concentration in secretions with a total LK score ( R = 0.3792). To diagnose ECRS, the highest area under the curve (0.8230) was determined for ECP in secretions; the highest area under the curve (0.6635) was determined for EOS% in secretions. Conclusion Measurement of ECP in nasal secretions is useful for non‐invasive diagnosis of ECRS. Level of Evidence 3 Laryngoscope , 133:3304–3312, 2023