# FeNO as a Non-Invasive Biomarker of Type 2 Inflammation in Chronic Rhinosinusitis with Nasal Polyps: Correlation with Serum IgE and Eosinophils

## TL;DR

This study explores FeNO as a non-invasive biomarker for type 2 inflammation in nasal polyps, showing its correlation with other markers like IgE and eosinophils.

## Contribution

The study demonstrates FeNO's potential as a supportive biomarker for type 2 inflammation in CRSwNP.

## Key findings

- FeNO strongly correlates with nasal eosinophilia (r = 0.53, p < 0.001).
- Serum IgE is significantly associated with disease severity scores.
- FeNO does not predict symptom or radiological severity.

## Abstract

Chronic rhinosinusitis with nasal polyps is a heterogeneous inflammatory disorder often driven by type 2 inflammation. Identification of non-invasive biomarkers, such as fractional exhaled nitric oxide (FeNO), may support the assessment and personalized management.

In this cross-sectional study, 141 patients with clinically and radiologically confirmed CRSwNP were assessed. FeNO levels, nasal eosinophilia, serum IgE, peripheral blood eosinophil counts, and skin prick test results were evaluated. Disease severity was measured using the SNOT-22 and Lund-Mackay CT scores.

FeNO showed a significant correlation with nasal eosinophilia (r = 0.53, p < 0.001), a moderate correlation with serum IgE (r = 0.40, p < 0.001), and a weak correlation with blood eosinophils (r = 0.17, p = 0.047). Serum IgE was significantly associated with both SNOT-22 and Lund-Mackay scores. FeNO did not show significant correlation with symptom severity or radiological extent, suggesting its use as a supportive marker rather than a stand-alone predictor.

FeNO may serve as a potential non-invasive marker for type 2 inflammation in CRSwNP, though it may not predict disease severity. Combining FeNO with other markers could improve clinical endotyping and management.