Host gene expression signatures of influenza A H1N1 and H3N2 virus infection in adults

Diagnosis of influenza A infection is currently based on clinical symptoms and pathogen detection. Use of host peripheral blood gene expression data to classify individuals with influenza A virus infection represents a novel approach to infection diagnosis We used microarrays to assay peripheral blood gene expression at baseline and every 8 hours for 7 days following intranasal influenza A H1N1 or H3N2 inoculation in healthy volunteers. We determined groups of coexpressed genes that classified symptomatic influenza infection. We then tested this gene expression classifier in patients with naturally acquired respiratory illness. We experimentally inoculated healthy volunteers with intranasal influenza A H1N1 and H3N2. Symptoms were documented and peripheral blood samples drawn into PAXgene RNA tubes for RNA isolation. We further enrolled patients presenting to the Emergency Department with naturally acquired respiratory illness, and documented symptoms and collected PAXgene RNA samples for RNA isolation.