Rhinovirus-Induced Exacerbations of Asthma and COPD

Hershenson, Marc B.

If indeed viral infections do cause exacerbations of asthma and COPD (and the preponderance of evidence suggests that this is so), what is the proposed mechanism by which viruses cause exacerbations? Rhinovirus, unlike influenza Scientifica 3 and other viruses, causes minimal cytotoxicity [36, 37] . Also, the amount of epithelial damage does not correlate with the severity of the symptoms, suggesting that symptoms are produced by processes independent of the severity of direct virus-induced damage to the epithelium. While selected studies have demonstrated cytotoxicity in various cell culture models [38] , epithelial cell death is considered unlikely to contribute in vivo to RV-induced exacerbations of chronic airways disease. The current explanation is that rhinovirus infection induces the release of chemokines from airway epithelial cells, thereby attracting inflammatory cells to the airways. In patients with preexisting airway inflammation, the influx of additional inflammatory cells caused by RV infection would lead to additive or synergistic effects and an exacerbation of airways disease.