Likewise, a higher steady state (10–40 min) fibrinolytic activity in pleural fluids from animals treated with scuPA based PAI‐1‐TFT (Figure 5e,g) compared to that for sctPA (Figure 5f,h) could indicate less plasmin associated with fibrin and contribute to worse outcomes with scuPA in rabbit empyema (Figure 2). This evidence concerns the gene SERPINE1 and empyema.