Following cecal ligation and puncture, a higher circulating CD4+T-cell level was observed in BTLA-/-mice. BTLA-/- mice were evaluated to assess whether a lack of B and T lymphocyte attenuator (BTLA) expression on CD4+ T cells diminished their capacity to circulate, 24 hours following cecal ligation and puncture (CLP). The level of circulating CD4+ T cells, however, was increased following CLP in the BTLA-/- mice (A). When the spleens of the BTLA-/- mice were observed, the level of CD4+ T cells in the sham BTLA-/- mice were significantly higher than both the wild-type (WT) sham and CLP mice, as well as the BTLA-/- mice that were subjected to CLP, suggesting that a lack of splenic apoptosis led to a higher level of circulating CD4+ T cells (B). Data are mean ± standard error of the mean. *P <0.05 using an unpaired, two-tailed Student’s t test.