Activated eosinophils in nasal polyps: a comparison of asthmatic and non-asthmatic patients

There is a recognized clinical association between nasal polyps and asthma. Nasal polyps and the airways of asthmatic patients demonstrate marked eosinophilia suggesting that this inflammatory cell may have a key role to play in both conditions. The objective of this study was to determine whether nasal polyps from patients with asthma had a greater density of activated eosinophils than patients with no associated respiratory disease.

Archived specimens were retrieved from patients who had undergone nasal polyp surgery and their case notes reviewed. Activated eosinophils were identified using immunohistochemistry for a monoclonal antibody to secreted eosinophil cationic protein (EG2).

Teaching hospital otolaryngology unit.

Consecutive patients who had undergone nasal polyp surgery in 1994 were recruited. The diagnosis of asthma was based on a documented physician diagnosis and appropriate drug treatment. Twenty-four asthmatic and 35 non-asthmatic patients were studied.

Eosinophil density was measured using a standardized counting technique.

Asthmatic patients were significantly more likely to have had previous polyp surgery (chi-square test: P < 0.05). Areas of intense eosinophilia were identified in all samples. There was a significant greater degree of activated eosinophilia in the asthmatic patients (t-test: P < 0.05).

We have demonstrated a higher number of previous operations in asthmatic patients, and also a greater degree of activated eosinophilia in asthmatic polyps compared with non-asthmatics. This would suggest that eosinophil activity has a role to play in the pathogenesis of nasal polyps.