Background: Leukotrienes, especially LTC4, are important inflammatory mediators in allergic and nonallergic inflammation of the entire airways. Of particular interest are numerous theories regarding the pathogenesis of aspirin intolerance with subsequent hyperproduction of leukotrienes and inhibition of cyclooxygenase.

Objective: To examine the influence of the cysteinyl-leukotriene receptor antagonist montelukast on clinical symptoms and inflammatory markers in nasal lavage fl uid in patients with bronchial asthma and nasal polyps, and determine its dependency on aspirin sensitization.

Methods: Twenty-four patients (7 women, 17 men; median age, 55.5 years) with nasal polyps and controlled asthma (n=12 with aspirin intolerance) were treated with 10 mg montelukast once daily for 6 weeks in a blinded, placebo-controlled fashion. The placebo phase was randomly assigned 4 weeks before (n=12) or after treatment (n=12). Symptom score, rhinoendoscopy, rhinomanometry, smears for eosinophils, and nasal lavages for the determination of different mediators were performed.

Results: Compared to placebo, there were significant improvements in the nasal symptom score and airflow limitation as well as a reduction in the inflammatory mediators in nasal lavage fluid after treatment. Furthermore, reduced eosinophils in nasal smears and peripheral blood were observed 2 and 6 weeks after treatment.

Conclusion: Leukotriene 1 receptor blockade led to a significant decrease in eosinophil inflammation accompanied by a reduction in other mediators such as neurokinin A and substance P in the nasal lavage fluid of patients with nasal polyps and asthma, with or without aspirin intolerance.

Key words: Polyposis nasi. ASA intolerance. Leukotrienes. Eosinophils. ECP. Substance p. Neurokinin A. Montelukast. Nasal lavage.