Blood eosinophil and basophil levels have recently been considered for genotyping chronic rhinosinusitis with nasal polyps (CRSwNP). Histologically, eosinophilic-type CRSwNPs have been associated with high recurrence rates after treatment.

The present study was the first to compare blood eosinophil and basophil counts in eosinophilic-type CRSwNP patients before and after endoscopic sinus surgery.

The study concerned 79 consecutive patients with histologically confirmed eosinophilic-type CRSwNP treated with endoscopic sinus surgery.

A significant drop in mean blood eosinophil counts and percentages occurred from before to after endoscopic sinus surgery in the cohort. Mean blood eosinophil counts and rates were also reduced after surgery in the sub cohorts of CRSwNP patients with asthma, AERD, and no allergy. Although blood eosinophil and basophil count 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.

The study concluded that endoscopic sinus surgery could clear polyps, remove inflammatory tissue, and reduce inflammatory cytokine levels. Consistently with the biological mechanism described, endoscopic sinus surgery could coincide with reducing blood eosinophils in eosinophilic-type CRSwNP.