Effect of Montelukast on Experimentally-Induced RV16 Infection in Asthma

Overview

People with asthma may have asthma worsening when they have an upper respiratory infection due to a virus or a common cold. Leukotrienes are increased in nasal secretions from children with Respiratory Syncytial Virus (RSV) and lung washings during times of acute lung inflammation. Experimental virus exposure in adults is also associated with increases in nasal leukotrienes. The degree to which leukotrienes play a role in asthma worsening is unknown.There is information linking leukotrienes to viral infections, allergic inflammation, and asthma exacerbation.This information supports the hypothesis that virus-induced leukotrienes contribute to the severity of respiratory infections and in susceptible individuals, lead to lower airway obstruction and exacerbations of asthma. We propose to use montelukast in an experimental viral challenge model to explore this hypothesis.

Viral infections are important causes of wheezing illnesses throughout childhood and in adults with asthma. There has been progress in identifying mechanisms and risk factors for severe respiratory symptoms, and in particular, wheezing. Given this close relationship, it would be attractive to apply antiviral strategies to the prevention and treatment of asthma, and both RV and RSV are obvious targets. Unfortunately, attempts at developing an RSV vaccine have so far been unsuccessful, and vaccination to prevent RV infection does not seem to be feasible due to the large number of serotypes. Antiviral medications have been tested in clinical trials, however one problem with this approach is that once the clinical signs and symptoms appear, viral replication is well underway. The other potential therapeutic approach for respiratory viral infections would be to selectively inhibit pro-inflammatory immune responses induced by the virus. The beneficial effects of systemic glucocorticoids indicate that this approach is valid; the challenge will be to develop treatments with greater efficacy and a reduced potential for adverse effects. The large body of information linking cysteinyl leukotrienes to viral infections, allergic inflammation, and asthma exacerbations, strongly supports the hypothesis that virus-induced leukotrienes contribute to the severity of respiratory infections and in susceptible individuals, lead to lower airway obstruction and exacerbations of asthma. We propose to use montelukast in an experimental viral challenge model to explore this hypothesis.