[Cytokines and chemokines induced by influenza virus infection]

Many kinds of cytokines and chemokines are produced in response to influenza virus infection through the course of cytokine cascade. Even a single cytokine exhibits various biological activities and different types of cells produce the same identical cytokine. In general, cytokines act to maintain the homeostasis of host condition. In influenza virus infection, it works as protective for the host against virus infection at its early stage, but often as pathogenic in its later stage. Cytokines play a pivotal role in establishment of virus specific immunity. However, over expression of cytokines causes irreversible severe damages to the host, including shock, disseminated intravascular coagulation, adult respiratory distress syndrome and multiple organ failure, a typical form of which is influenza encephalopathy. Pathogenicity of influenza virus might be determined by means of its potential capability to induce proinflammatory cytokines.