Montelukast effects on inflammation in allergic rhinitis: a double blind placebo controlled pilot study

It has been demonstrated that Leukotriene modifiers reduce rhinitis symptoms, but montelukast preventive effect on inflammatory cells pattern in intranasal challenge studies has not been already assessed. This pilot study has been designed to explore the montelukast effects in preventing early/late inflammatory cells response to specific allergen challenge in persistent rhinitis. After a 4 week wash-out period, patients were randomised to receive montelukast/placebo for 4 weeks. Pre-post treatment nasal washing and scraping before and after specific nasal challenge were performed. No difference in baseline inflammatory cells count before and after treatment was shown between groups. Despite at a basal level a decrease of inflammatory cells in active group after treatment was observed, the statistical significance was not reached. The generalised mixed model showed that, after therapeutic interventions, the inflammatory cells increased 30' and 6 hour after challenge but, only in the active group the cells amounting was less for eosinophils (-34%), macrophages (-56%), lymphocytes (-45%) and neutrophils (-46%; p=0.001). The longitudinal generalised linear model with just one time variable showed a decrease of all inflammatory cellular types although a significant relevance was reached only for macrophages (p=0.038) and neutrophils (p=0.001). The modulatory effect on neutrophils and macrophages could lead to montelukast still unexplored effects. Specific trials, sized according to the results of this pilot exploratory study, could add relevant evidences concerning the leukotrienes receptors antagonist treatment of specific rhinitis and asthma phenotypes.