Our previous study demonstrated that sepsis could obviously promote the negative immunoregulation of CD4+CD25+Tregs and Nrp-1highCD4+CD25+Tregs, especially Nrp-1highCD4+CD25+Tregs, but weakened the negative immunoregulation of Nrp-1lowCD4+CD25+Tregs, which correlated to the expressions of Foxp-3/CTLA-4, as well as the secretion of IL-10 and TGF-β [23]. Here, CTLA4 is linked to Sepsis.