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.