Clinical factors influencing the eosinophil infiltration of nasal polyps

Our study, based on a retrospective chart analysis, was aimed 1) to describe the varying degree of eosinophil infiltration in a series of 263 adult patients operated on diffuse and bilateral nasal polyposis (NPS) after failure of medical treatment, in 15 cystic fibrosis patients with bilateral nasal polyps, and in 31 patients with chronic sinusitis without polyps (18 bilateral, 13 unilateral) 2) to search for clinical factors that might influence the degree of eosinophil infiltration. Eosinophil infiltration was expressed semi-quantativity as a percentage of inflammatory cells.

Our study confirms that eosinophil infiltration is a striking feature of nasal polyposis. All patients with chronic sinusitis showed less than 10% eosinophils (mean +/- SEM = 2 +/- 2%) whereas 88% of patients with NPS showed more than 10% eosinophils (50 +/- 2%). Cystic fibrosis lied in between with 40% of patients showing more than 10% eosinophils. In idiopathic bilateral NPS the number of eosinophils was increased in patients with asthma (58 +/- 3%) and even more in Widal's triad (75 +/- 4%). Atopic patients did not have more eosinophils (52 +/- 5%). Patients treated with systemic steroids within two months before surgery showed decreased eosinophil infiltration (22 +/- 3% vs 50 +/- 2 for treated versus untreated) whereas patients treated with topical steroids did not (47 +/- 2%).

Thus, a link might exist between clinical presentation and eosinophil infiltration. Chronic sinusitis and nasal polyps are probably not the same disease. Eosinophils appear as a link between nasal polyps, asthma and aspirin intolerance. Atopic status does not modify eosinophil infiltration of nasal polyps. Systemic steroids appear significantly more effective to reduce the eosinophil infiltrate than topical steroids in our selected group of operated patients.