Transfusion-related acute lung injury (TRALI) can be a life-threatening complication of transfusion. In its severe form, it is clinically indistinguishable from acute respiratory distress syndrome. Symptoms typically begin within 4 hours of transfusion. TRALI has been reported after transfusion of all plasma-containing blood components. TRALI is associated with antibodies to white blood cells and biologically active lipids in transfused blood components.