In this study, we also found that despite using lager dosage of anti-CD25 mAb to deplete CD4+CD25+ T regs enhanced resistance to subsequent infections and improved the survival of sepsis mice when challenged with secondary chronic peritonitis, this approach significantly increased the early death in sepsis mice when challenged with sub-acute peritonitis due to potentially fatal hyperinflammatory to subsequent severe infection. Here, CD4 is linked to peritonitis.