PLAT and viral infectious disease: Annexin A2, a calcium- and phospholipid-binding protein, is an endothelial surface co-receptor for tissue plasminogen activator (tPA) and plasminogen that stimulates the profibrinolytic state.78 There is increasing evidence for a role of annexin A2 at the first phase of viral life cycle known as cell attachment and entry in a variety of viral infections.79 SARS-associated cytokines (IL-6 and IFN-gamma) have been shown to upregulate the expression of annexin A2.80 The plasma kallikrein is involved in many proteolytic activities.