IFNL1 and influenza: Since the discovery of type III IFNs (IFN-λ-1, -2, and -3; also known, respectively, as IL-29, IL-28A, and IL-28B in humans, IFN-λ1 being a pseudogene in mice) in 2003 (Kotenko and others 2003; Sheppard and others 2003), much of the controversy surrounding the relationship between type I IFN and influenza has been clarified.