TGFB1 and injury: A beneficial role is observed in experimental studies where TGF-β1 is expressed at high levels during normal lung development.[5, 39] Moreover, TGF-β1 is also involved in normal tissue repair following lung injury.[40, 41] Nevertheless, a harmful role of TGF-β1 in the development of acute lung injury has been reported.[17, 15] These pleiotropic functions of TGF-β1 and its complex regulation could limit its prognostic value.