Eosinophils are the dominant type2 marker for the current indication of biological treatment in severe uncontrolled chronic rhinosinusitis with nasal polyps

The latest European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS2020) defines markers for type2 inflammation in the context of indicating biological therapy in severe uncontrolled chronic rhinosinusitis with nasal polyps (CRSwNP) as either a total serum immunoglobulin E (total-IgE) >100 kU/L, a blood eosinophil count (BEC, expressed as ·109 cells / L) ≥0.25, or a tissue eosinophil count ≥10 per high power field (HPF) (1). Recently, an EPOS/EUFOREA expert panel advised to lower the threshold for BEC from ≥0.25 (EPOS2020) to ≥0.15 (EUFOREA2023) to align with thresholds used for biological indication in asthma patients (2). As far as we know, there is no literature supporting the cut-off value for total-IgE.