Together with other findings from human sepsis patients or rodent sepsis models, including the up-regulation of well established inhibitory co-receptors such as PD-1 and CTLA-4 on T-lymphocytes [33], [34], [77], these data argued for a functional paralysis of T-lymphocytes, although an exhaustive and comprehensive characterization of T-cell functionality in acute sepsis had not yet been reported. Here, CTLA4 is linked to Sepsis.