Impaired virus-induced interferon-α2 release in adult asthmatic patients

Background Interferon-alpha (IFN-alpha) not only serves as a first defence line of the immune system against viral attacks but also interacts with T-helper type 1 (Th1)/ T-helper type 2 (Th2) regulation and various other cell types like basophils and monocytes, thereby linking innate and acquired immunity. Recently, we demonstrated that children with allergic asthma produced significantly lower amounts of virus-induced IFN-alpha 2 compared with healthy children or those with intrinsic asthma. Objective In this study, we extend our analysis to examine in a cohort study whether IFN-alpha 2 is also reduced in allergic asthma of adults. Methods Adults with allergic asthma and healthy controls were prospectively recruited. Blood cultures were stimulated with different viruses (respiratory syncytial virus (RSV), newcastle disease virus (NDV)) and analysed for IFN-alpha 2 protein release and gene transcription. Results Virus-induced IFN-alpha 2 release from blood cells of allergic asthmatic patients was significantly reduced compared with healthy controls, independent of the virus used (NDVasthma=221 +/- 134 pg/mL, NDVhealthy=555 +/- 341 pg/mL, P=0.003 and RSVasthma=46 +/- 27 pg/mL, RSVhealthy=108 +/- 90 pg/mL, P=0.014). Values=mean +/- standard deviation). It was not influenced by medication, especially cortico-steroids. IFN-alpha 2 mRNA expression 5 h after NDV stimulation confirmed the ELISA results and correlated well with release data (r=0.397, P=0.033). Conclusion Like children, adults with allergic asthma show impaired virus-induced IFN-alpha 2 release in whole blood, indicating a systemic phenomenon in patients with bronchial asthma and atopic phenotype. Impaired virus-induced IFN-alpha release could be a marker of inflammation in chronic allergic asthma.