Production of interferon in respiratory syncytial virus bronchiolitis.

Production of interferon alfa in vitro was significantly reduced during acute respiratory syncytial virus bronchiolitis but subsequently returned to normal. Nasopharyngeal and endotracheal interferon alfa were detected intermittently and in low concentrations. The degree of impairment of in vitro production and poor in vivo production of interferon alfa suggest the need for a therapeutic trial of nebulised or systemic interferon in acute bronchiolitis.