Recent reports attributed various changes in cytokine levels, such as TNF-α, IL-6, type I IFN, IL-10, and IL-27 (16, 30, –, 33), as well as changes in immune cells’ composition [e.g., monocytes, T cells, and B cells (17, 18, 34, 35)], which occur during the viral infection and in turn limit the innate pulmonary host defense against the subsequent bacterial invasion. The gene discussed is IL27; the disease is viral infectious disease.