IL6 and viral infectious disease: During bacterial and viral infections, local sensor cells in respiratory tract, including airway epithelia cells, alveolar macrophages and dendritic cells, firstly response to pathogens and secret the first-order cytokines, such as type I and III IFN, IL-6, TNF-α, IL-12, IL-25, IL-33, IL-1β, etc. (Happel et al., 2005; Liu, 2005; Khaitov et al., 2009; Barlow et al., 2013).