PLG and influenza: Additional studies in SARS-CoV and influenza found dysregulation of urokinase, coagulation, and fibrinolysis pathways contributed to the severity of lung injury, possibly through altering the hemostatic balance with subsequent coagulation-induced ischemic injury.92 Plasminogen was protective against severe influenza A, H5N1, and H1N1 infections.93 These groups hypothesized that increased fibrinolysis led to a positive feedback loop of vascular permeability, leukocyte recruitment, and fibrin generation.