Clinical correlations of transcriptional profile in patients infected with avian influenza H7N9 virus

Background. Avian influenza A (H7N9) viruses emerged in China in 2013 and caused zoonotic disease associated with a case-fatality ratio of over 30%. Transcriptional profiles in peripheral blood reflect host responses and can help to elucidate disease pathogenesis. Methods. We correlated serial blood transcriptomic profiles of patients with avian influenza A (H7N9) virus infection and determined the biological significances from the analysis. Results. We found that specific gene expression profiles in the blood were strongly correlated with the Pao₂/Fio₂ ratio and viral load in the lower respiratory tract. Cell cycle and leukocyte-related immunity were activated at the acute stage of the infection while T-cell functions and various metabolic processes were associated with the recovery phase of the illness. A transition from systemic innate to adaptive immunity was found. Conclusions. We developed a novel approach for transcriptomic analysis to identify key host responses that were strongly correlated with specific clinical and virologic parameters in patients with H7N9 infection.