F2 and viral infectious disease: In addition to inflammatory cytokines/chemokines, the expression levels of coagulation-related factors, prothrombin-encoding F2, tissue factor-encoding F3, and plasminogen activator inhibitor type 1 (PAI-1) encoding serine protease inhibitor, clade E, member 1 (Serpine1) were upregulated by virus infection in the lungs and/or liver of aged hamsters (Figure 4).