LAUSR

To the Editor: Regulatory T‐cells (Tregs), a subset of CD4+ T‐cells, have the capacity to actively suppress immune responses and play a pivotal role in sepsis‐induced immunosuppression.[1] B‐ and T‐lymphocyte attenuator (BTLA) is a co‐inhibitory receptor that is known to potently inhibit CD4+ T‐cell function and to block prosurvival signaling in CD4+ T‐cells.[2] Tregs constitutively express BTLA. It has been reported that the absence of BTLA expression on Tregs resulted in reduced interleukin‐10 production by Tregs in a model of established experimental autoimmune encephalomyelitis.[3] However, the role of BTLA expression on Tregs in patients with sepsis has rarely been investigated. In this study, we investigated the dynamic changes in BTLA expression on Tregs on days 1 and 7 during sepsis and explored the potential role of BTLA expression on Tregs. We used the combination of the surface markers CD4, CD25, and CD127 to identify Tregs.