Figure 5.
Overview of cellular changes occurring during sepsis. The first line shows the correct activation of the immune system during infection. If the innate and adaptive immune systems fail to contain the ongoing infection locally, the infection spreads systemically, triggering a hyperinflammatory innate and adaptive immune response. Further progression of infection and spread of the dysfunctional and altered cellular responses, including changed surface receptor expression, inappropriate inflammatory mediator secretion, and untimely apoptosis of immune cells, lead to the development of sepsis (middle panel). To regulate hyperinflammatory immune cell activities, the body goes through a loss of balance between inflammatory and anti-inflammatory response and a generalized immunosuppressive stage (bottom panel). As described in the figure, different phenotypic and molecular changes take place in immune cells as sepsis progresses. Thus, a host response that is designed to protect against pathogens causes tissue-damaging events, leading to multi-organ system failure and death. (Legend: : decrease).