IL-33: a jack of all trades in the orchestration of respiratory antibacterial immunity

Influenza A virus(IAV)is the causative agent of mostly mild to moderate seasonal respiratory infections and several pandemic outbreaks,the most recent of which was reported in 2009.Previous IAV pandemics were associated with an enormous death toll;for example,the 1918 H1N1 pandemic affected hundreds of millions of people globally and resulted in~50 million deaths.1 Microbiologic analyses of patient samples revealed a strong incidence of bacterial pathogens in fatal complications of viral infection.2 To date,many pieces of epidemiologic and experimental evidence reveal pronounced susceptibility to detrimental bacterial superinfection in IAVinfected individuals.