脓毒症是机体对感染免疫失调导致危及生命的器官功能障碍。当感染发生时，病原体相关分子模式(pathogen-associated molecular patterns，PAMPs)启动炎症反应，以清除病原体。然而，免疫系统的强烈激活可能导致细胞功能障碍和器官衰竭。其受损的宿主细胞释放损伤相关分子，并通过损伤相关分子模式(damage-associated molecular patterns，DAMPs)途径放大炎症反应形成细胞因子风暴。有趣的是，在脓毒症期间，中性粒细胞从强大的抗菌保护效应转变为组织损伤和器官功能障碍的危险介质。而血液净化作为脓毒症的重要治疗策略，其清除目标也发展到了除炎症介质外的免疫细胞。这篇综述总结了脂多糖、细胞因子、DAMPs和中性粒细胞在脓毒症发病机制中的作用，详述了脓毒症时靶向内毒素、细胞因子、炎症级联反应上游(免疫细胞)的不同血液净化方式及相应的临床研究。

Sepsis is complicated with dysregulation of immune system to infection, which may lead to life-threatening dysfunction of organs. In the presence of infections, pathogen-associated molecular patterns (PAMPs) initiate inflammatory responses to clear the pathogens, but hyper-activated responses of the immune system may injure the host cells and organs. Damage-associated molecules released by the injured cells amplify the inflammatory responses and may progress to develop a cytokine storm through the damage-associated molecular patterns (DAMPs) pathway. In sepsis, neutrophils shift from potent antimicrobial protectors to destructive mediators to tissues and organs. Blood purification removes the inflammatory mediators as well as the immune cells with adverse functions, and becomes an important approach for the treatment of sepsis. Here we summarize the roles of lipopolysaccharides, cytokines, DAMPs and neutrophils in the pathogenesis of sepsis. We also introduce a series of blood purification methods and their clinical trials targeting the clearance of endotoxins, cytokines, and immune cells at the upstream of inflammatory cascade in sepsis.