Non-eosinophilic chronic rhinosinusitis with nasal polyps: blood eosinophil, basophil, and neutrophil counts before and after surgery.

Objectives: Research selectively investigating non-eosinophilic chronic rhinosinusitis with nasal polyps (CRSwNP) is lacking. The inflammatory patterns seen in non-eosinophilic CRSwNP are still poorly understood. The present study is the first to compare blood eosinophil, basophil, and neutrophil counts before/after surgery in patients with non-eosinophilic CRSwNP stratified by their clinical features. Methods: The study concerned 107 consecutive patients with histologically confirmed non-eosinophilic CRSwNP who underwent endoscopic sinus surgery (ESS). Results: Statistical analysis ruled out any significant change in mean blood eosinophil, basophil, and neutrophil counts after ESS. A significant positive correlation emerged between blood eosinophil and basophil counts in both pre- and post- ESS laboratory tests. In the subcohort of allergic patients, a significant negative correlation was found after ESS between eosinophil and neutrophil levels and between basophil and neutrophil levels. Conclusions: In eosinophilic CRSwNP, ESS can clear polyps, remove inflammatory tissue, and reduce the inflammatory cytokines it generates, with a consequent reduction in blood eosinophil levels. The different results in non-eosinophilic CRSwNP support the conviction that the 2 types of CRSwNP are entities with distinct inflammatory response patterns.