Blood Eosinophil and Basophil Values Before and After Surgery for Eosinophilic-type Sinonasal Polyps

Background: Blood eosinophil and basophil levels have recently been considered for the purpose of endotyping chronic rhinosinusitis with nasal polyps (CRSwNP). Histologically, eosinophilic-type CRSwNPs have been associated with high recurrence rates after treatment. Objective: The present study was the first to compare blood eosinophil and basophil counts in eosinophilic-type CRSwNP patients before and after endoscopic sinus surgery. Methods: The study concerned 79 consecutive patients with histologically confirmed eosinophilic-type CRSwNP treated with endoscopic sinus surgery. Results: A significant drop in mean blood eosinophil counts and percentages occurred from before to after endoscopic sinus surgery in the cohort as a whole. Mean blood eosinophil counts and percentages were also reduced after surgery in the subcohorts of CRSwNP patients with (i) asthma, (ii) aspirin-exacerbated respiratory disease (AERD), and (iii) no allergy. Although blood eosinophil and basophil counts correlated directly before and after surgery, a statistical reduction in blood basophil counts and percentages after surgery emerged only in the subcohort of nonallergic CRSwNP patients. Conclusion: Endoscopic sinus surgery can clear polyps, remove inflammatory tissue, and reduce inflammatory cytokine levels. Consistently with the biological mechanism described, endoscopic sinus surgery could coincide with a reduction in blood eosinophils in eosinophilic-type CRSwNP.