Transfusion-related acute lung injury (TRALI) is one of the leading causes of transfusion-related fatalities and to date, without available therapies. Here we investigated the role of the complement system in TRALI. Murine anti-major histocompatibility complex (MHC) class I antibodies were used in TRALI mouse-models, in combination with analyses of TRALI patient plasma samples. We found that in vitro complement activation was related to in vivo antibody-mediated TRALI induction, which …