KLK4 and systemic inflammatory response syndrome: This leads to the complement system, the kallikrein system, neutrophils and vascular endothelial cell activated, cell surface adhesion molecule expression, mast cell degranulation, tumor necrosis factor (TNFα), interleukin (e.g. IL-1β, IL-6, IL-8) and other cytokines signaling cascad style released,which triggered ECMO-related SIRS [14-17].