Metabolic reprogramming and dysregulated IL-17 production impairs CD4 T cell function post sepsis.

Sepsis survivors are at high risk for infection-related rehospitalization and mortality for years following the resolution of the acute septic event. These infection-causing microorganisms generally do not cause disease in immunocompetent hosts, suggesting that the post-septic immune response is compromised. Given the importance of CD4 T cells in the development of long-lasting protective immunity, we analyzed their post-septic function. Here we showed that sepsis induced chronic increased and non-specific production of IL-17 by CD4 T cells, resulting in the inability to mount an effective immune response to a secondary pneumonia challenge. Altered cell function was associated with metabolic reprogramming, characterized by mitochondrial dysfunction and increased glycolysis. This metabolic reprogramming began during the acute septic event and persisted long after sepsis had resolved. Our findings reveal cell metabolism as a potential therapeutic target. Given the critical role of cell metabolism in the physiological and pathophysiological processes of immune cells, these findings reveal a potential new therapeutic target to help mitigate sepsis survivors' susceptibility to secondary infections.