A narrative review of the role of the complement system in sepsis

Sepsis is a common syndrome with a high mortality rate worldwide, characterized by complex physiological, pathological, and biochemical abnormalities. The complement system, an essential component of innate immunity, consists of approximately 30 proteins that undergo a series of cascading enzymatic reactions to form a membrane attack complex, leading to cell lysis. Sepsis-induced complement activation drives endothelial cells toward a proinflammatory and prothrombotic phenotype. This review highlights the complex interactions among the complement, coagulation, and inflammatory systems, examines the prognostic significance of complement activation in patients with sepsis, and discusses the potential clinical applications of complement inhibitors.