PDCD1 and Sepsis: Adoptive transfer of regulatory T cells (Tregs) before induction sepsis in mice subjected to hemorrhagic insult demonstrates reduced infiltration of neutrophils and lung injury, an effect which is ablated using adoptive transfer of PD-1 deleted Tregs, indicating that PD-1 expressing Tregs dampen the innate leukocyte mediated exaggerated inflammation and protect against sepsis-induced acute lung injury (105).