Fig. 1. A microbial infection can trigger a local or systemic inflammatory response.

Upon disruption of epithelial barrier, microbial pathogens invade and elicit an innate immune response at infection site. If invading pathogens are effectively ingested and eliminated by neutrophils and macrophages, local inflammation resolves normally to regain immunological homeostasis. Otherwise, invading pathogens can leak into the blood stream, and trigger a potentially injurious systemic inflammatory response that could lead to sepsis.