Neutrophil heterogeneity and its role in infectious complications after severe trauma

Concept of inflammatory response after trauma. Trauma leads to a rapid immune activation, during which the most competent neutrophils are mobilized into tissues, leaving supposedly less competent neutrophils behind in the circulation. The green lines represent the uncomplicated course after trauma. The immune response can become dysregulated by overwhelming immune activation (upper red line), a refractory immune state (lower red line) or low-grade inflammation and immune impairment later on (both red lines). The vertical axis indicates the immune status. The horizontal axis represents time after trauma. SIRS systemic inflammatory response syndrome, PICS persistent inflammation, immunosuppression, and catabolism syndrom