Blood IgE and Eosinophils are not Reliable Predictors of Nasal Tissue Eosinophils in Chronic Rhinosinusitis with Nasal Polyposis

<b>Introduction</b> Chronic rhinosinusitis with nasal polyposis (CRSwNP) is a chronic inflammatory condition of the paranasal sinuses that is mainly associated with type-2 inflammation. Immunoglobulin E (IgE) and eosinophils in blood and nasal tissue have been suggested as biomarkers for the prognosis and severity of CRSwNP as well as indications for biological treatment. <b>Objective</b> The present study aims to assess the relationships between blood IgE concentration, blood eosinophil count, and nasal polyp eosinophil count in CRSwNP patients. <b>Methods</b> The present study is retrospective. Nasal polyps from CRSwNP patients (n = 73) were fixed and embedded in paraffin for hematoxylin and eosin stain. Blood was collected to measure IgE concentration and eosinophil count. <b>Results</b> Weak correlations were found between blood and tissue eosinophil counts ( <i>p</i> = 0.004, r = 0.367) as well as blood IgE concentration and blood eosinophil count ( <i>p</i> = 0.007, r = 0.372). There was no statistically significant correlation between blood IgE concentration and tissue eosinophil count. When dividing patients based on nasal polyp eosinophil count, blood eosinophil level was higher in the severely eosinophilic group than in the mildly eosinophilic group ( <i>p</i> = 0.002). <b>Conclusion</b> Blood IgE and eosinophils are not reliable biomarkers to predict the inflammatory condition in CRSwNP. Further research is needed on the clinical roles of these biomarkers.