Supplementary Material for: Relationship between Eosinophilic and Neutrophilic Inflammation in Chinese Chronic Rhinosinusitis with Nasal Polyps

Introduction: Chronic rhinosinusitis with nasal polyps (CRSwNPs) in China is characterized by a mixed eosinophilic-neutrophilic inflammation, linking to a more heterogeneous clinical phenotype. However, the relationship between eosinophilic and neutrophilic inflammation in Chinese patients with CRSwNP remains largely unknown. We aimed to further characterize the correlation between neutrophils with eosinophils in relation to clinical characters and disease control status after endoscopic sinus surgery (ESS). Methods: A total of 242 patients were recruited and stratified based on tissue (≥10%) eosinophilia and (≥20/per high-power field) neutrophilia. Clinical characteristics and disease control status were compared between subgroups. Associations between tissue eosinophils and neutrophils were analyzed. Results: The uncontrolled patients accounted for 41.3%, 41.3%, 17.1%, and 22.2% in subjects with concomitant tissue eosinophilia and neutrophilia (EN-high), isolated eosinophilia (E-high), isolated neutrophilia (N-high), and no eosinophilia and neutrophilia (EN-low), respectively. Positive correlations between tissue eosinophils and neutrophils were observed in patients with CRSwNP as well as in EN-high and N-high subgroups but not in E-high and EN-low subgroups. The EN-high subgroup had higher tissue eosinophil numbers than the other three subgroups. Both EN-high and E-high subgroups had higher rates of uncontrolled subjects than the N-high and EN-low subgroups; however, there was no difference in the rate of uncontrolled subjects between EN-high and E-high subgroups and between N-high and EN-low subgroups. Conclusion: Tissue neutrophils might have a potential interaction and mutual promotion effect with eosinophils in CRSwNP. However, tissue neutrophilia would not pose significant risk for poor disease control after ESS. Further larger, prospective studies are needed to confirm our findings.