Comparison of Interferons and Other Biomarkers in Influenza and Healthy Donor Samples

Abstract

Toward an understanding of biomarkers for acute viral diseases we have examined Influenza serum in comparison to healthy donors. We determined the levels of Interferon (IFN) Alpha, Beta, Gamma as well as Neopterin and Beta-2 Microglobulin (B2M) by ELISA in the Serum of 38 Influenza and 65 healthy donors using commercial assays. We measured chemokines and proinflammatory cytokines as biomarkers for IFN Activity by electrochemiluminescence. Assays were performed according to the manufacturer’s protocol. IFN-Omega levels were determined using a newly developed ultra-sensitive single molecule assay sensitive to 0.04 pg/ml. Percentile stratification was by Mann-Whitney non-parametric testing and correlations were determined under Spearman conditions. None of the healthy donors exhibited quantifiable IFN-Alpha or Beta and only two had detectable levels of IFN-Omega. Within the Flu cohort, 68.5% of samples contain quantifiable IFN-Alpha and Omega and 39.5% had IFN-Beta. 79% of the Flu samples displayed IFN-Gamma levels above the 95th percentile determined from the healthy donor distribution. Neopterin, B2M, and CXCL-10 were all significantly elevated in the Flu cohort versus the healthy subclass. Other chemokines either showed no correlation or a mild negative correlation. There was a striking concordance between IFN-Alpha and Omega levels. To our knowledge this is the first study to measure IFN-Omega and a broad panel of other analytes in Flu samples. As such this study may provide a beginning to discriminate between different viral diseases.