Peripheral blood eosinophilia correlates with hyperplastic nasal polyp growth

BackgroundEosinophils are thought to play a significant role in nasal polyposis, but the exact mechanism by which they contribute to polyposis remains unclear. Therefore, we proposed to test the hypothesis that peripheral blood eosinophilia (PBE) is a surrogate and biomarker for polyp load. To do this, we examined whether PBE levels correlate with nasal polyp load in a longitudinal manner. MethodsWe retrospectively analyzed the fluctuation of PBE and nasal polyp load in each patient (n = 61) assessed preoperatively, 1-2 months postoperatively, and 3-12 months postoperatively. Nasal polyp load was assessed using computed tomography (CT) scan preoperatively and nasal endoscopy postoperatively. Correlation coefficients were analyzed using parametric statistics. ResultsThere was a positive correlation between initial preoperative baseline PBE and CT scan staging of polyp load (r = 0.35, p < 0.01). When patients were analyzed longitudinally, we found that the change in PBE correlated with the change in nasal endoscopy scores obtained at or near the same timepoint (r = 0.82, p < 2.0 x 10(-10)). When nasal polyp load increased with time, we observed a stepwise increase in eosinophil counts (r = 0.37, p < 0.02). ConclusionsPBE correlates with nasal polyp load. PBE levels may be used along with nasal endoscopy to prospectively follow nasal polyp load postoperatively in chronic rhinosinusitis patients with hyperplastic nasal polyposis who have eosinophilia, asthma, and/or aspirin-exacerbated respiratory disease.