Given BTLA’s role in diminishing CD4+ T-cell function [18,31] and pro-survival signaling [20], we looked for differences in BTLA expression on these cells from the peripheral blood of septic (n = 11) compared with nonseptic/SIRS (n = 28) critically ill ICU patients to assess whether increased BTLA expression may be a marker for poor septic outcomes, potentially due to BTLA-induced CD4+ T-cell apoptosis and/or diminished function (patient characteristics are described in Table 1). This evidence concerns the gene BTLA and systemic inflammatory response syndrome.