Respiratory syncytial virus infections in the adult asthmatic--mechanisms of host susceptibility and viral subversion.

Respiratory syncytial virus (RSV), a single-stranded RNA virus of the Paramyxoviridae family, is a major cause of bronchiolitis in infants and is also conjectured to be an early-life influence on the development of asthma. Although the data supporting a role for RSV in bronchiolitis in children are robust and evidence to support its role in juvenile asthmatics exists, RSV's role in asthma pathogenesis in adults is not as clearly defined. The authors review the literature to further elucidate RSV's impact on adult asthmatics, including its importance as a cause of asthma exacerbations. They examine the morbidity associated with RSV infection and how the immune response may differ between adult asthmatics and nonasthmatics. They review the responses by specific cell types from adults with asthma that are stimulated by RSV. They also consider the role of early-life exposure to RSV and its contribution to asthma in adults. Lastly, they review the mechanisms by which RSV evades normal host immune responses and subverts these responses to its benefit.