Cytokine and chemokine gene expression profile of influenza-virus-infected human bronchial epithelial cells by quantitative RT-PCR. Cytokine and chemokine mRNA concentration were assayed 3 h and 6 h after infection with A/Hong Kong/483/97 (H5N1/97), A/Vietnam/1194/04, A/Vietnam/3046/04 (both H5N1/04) and A/Hong Kong 54/98 (H1N1) influenza viruses or in mock infected cells. When compared with H1N1 infected cells, H5N1/97 and both H5N1/04 influenza viruses significantly up-regulated IP-10, RANTES and IL-6 (p < 0.001) and interferon beta (p < 0.01) at 6 hours post-infection (Bonferroni multiple comparison test). Both H5N1/04 viruses significantly up-regulated MCP-1 and IL-8 to levels higher than H1N1 and H5N1/97 infected cells (p < 0.05, Bonferroni multiple comparison test). The mRNA concentrations of cytokine and chemokine mRNA were normalized to those β-actin mRNA in the corresponding samples. Means and standard deviation of duplicate cultures and assays are shown.