Respiratory viral infections in children with asthma: do they matter and can we prevent them?

Ahanchian, Hamid; Jones, Carmen M; Chen, Yueh-sheng; Sly, Peter D

While definitive data are yet to be produced, experimental HRV infections in adult volunteers initially suggested that asthmatics were more likely to develop lower respiratory infections (LRI) than healthy adults, i. e. less likely to be able to limit viral replication to the upper airways [19, 20] . Subsequent in vitro infection of primary airway epithelial cells from asthmatic and healthy adults with HRV have demonstrated that asthmatic cells produce less IFN-β [21] and IFN-λ [22] making them potentially more susceptible to infection, slower to clear infection, and more susceptible to virus-induced cell cytotoxicity. Deficiencies in the IFNα response of peripheral blood mononuclear cells and plasmacytoid dendritic cells from asthmatic adults and children has also been observed, in these particular studies, in response to RSV, HRV [14, 15] and Influenza A [23] . It is likely that the overall impaired innate immune response of the asthmatic airway epithelium is a result of deficiencies in the antiviral response of both epithelial cells and immune cells. Childhood, especially infancy, is characterized by developmentally-regulated deficiencies in innate and adaptive immunity [24] . Such deficiencies are likely to increase the risk of viral LRI in children, especially in those at high risk for asthma and allergies.