Predictive value of tissue eosinophilia for dupilumab response in chronic rhinosinusitis with nasal polyps: A retrospective monocentric study

Objective: To evaluate the predictive value of baseline tissue eosinophilic infiltration (cells/highpower field [HPF]) in determining clinical response to dupilumab in patients with chronic rhino-sinusitis with nasal polyps (CRSwNP). Methods: This retrospective, single-center observational study included patients with severe, refractory CRSwNP treated with dupilumab between December 2020 and December 2024. Based on histopathological analysis of nasal polyp biopsies, patients were stratified into 2 groups according to tissue eosinophil density: <50 cells/HPF and >= 50 cells/HPF. Clinical response was assessed through patient-reported outcomes (SNOT-22) and objective measures including Nasal Polyp Score (NPS), Lund-Kennedy Score (LKS), and Lund-Mackay Score (LMS), evaluated at baseline and after 1, 3, and 12 months of treatment. Repeated-measures ANOVA was used to evaluate within-group and between-group differences over time. Results: Eighty-six patients were included in the analysis: 57 with low eosinophilic infiltration (<50 cells/HPF) and 29 with high infiltration (>= 50 cells/HPF). Patients with high tissue eosinophilia showed significantly greater improvement in SNOT-22 scores across all time points (p = 0.045). No significant between-group differences were found in endoscopic (NPS, LKS) or radiologic (LMS) outcomes throughout the follow-up period. Conclusions: Dupilumab confirmed high clinical efficacy, rapid symptom improvement, and good tolerability in patients with CRSwNP. Higher tissue eosinophil counts were associated with greater symptom improvement, as measured by SNOT-22. These findings suggest a potential role for tissue eosinophilia as a predictive marker of clinical response.