[Evaluation of peripheral blood T-lymphocyte subpopulations features in patients with hepatitis B virus-related acute-on-chronic liver failure based on single-cell sequencing technology].

Objective: T lymphocyte exhaustion is an important component of immune dysfunction. Therefore, exploring peripheral blood-exhausted T lymphocyte features in patients with hepatitis B virus-related acute-on-chronic liver failure may provide potential therapeutic target molecules for ACLF immune dysfunction. Methods: Six cases with HBV-ACLF and three healthy controls were selected for T-cell heterogeneity detection using the single-cell RNA sequencing method. In addition, exhausted T lymphocyte subpopulations were screened to analyze their gene expression features, and their developmental trajectories quasi-timing. An independent sample t-test was used to compare the samples between the two groups. Results: Peripheral blood T lymphocytes in HBV-ACLF patients had different differentiation trajectories with different features distinct into eight subpopulations. Among them, the CD4(+)TIGIT(+) subsets (P = 0.007) and CD8(+)LAG3(+) (P = 0.010) subsets with highly exhausted genes were significantly higher than those in healthy controls. Quasi-time analysis showed that CD4(+)TIGIT(+) and CD8(+)LAG3(+) subsets appeared in the late stage of T lymphocyte differentiation, suggesting the transition of T lymphocyte from naïve-effector-exhausted during ACLF pathogenesis. Conclusion: There is heterogeneity in peripheral blood T lymphocyte differentiation in patients with HBV-ACLF, and the number of exhausted T cells featured by CD4(+)TIGIT(+)T cell and CD8(+)LAG3(+) T cell subsets increases significantly, suggesting that T lymphocyte immune exhaustion is involved in the immune dysfunction of HBV-ACLF, thereby identifying potential effective target molecules for improving ACLF patients' immune function.目的： 耗竭T细胞是免疫功能障碍的重要组成部分。探讨乙型肝炎病毒相关慢加急性肝衰竭（HBV-ACLF）患者外周血耗竭T淋巴细胞特点，为ACLF免疫功能障碍患者提供潜在的治疗靶点分子。 方法： 选取6例HBV-ACLF患者和3例健康对照者采用单细胞RNA测序方法进行T细胞异质性检测，并且筛选耗竭T淋巴细胞亚群，分析其基因表达特点，并且通过拟时间分析其发展轨迹。两组样本之间比较采用独立样本t检验分析。 结果： HBV-ACLF患者外周血中T淋巴细胞具有不同的分化轨迹，可分化为8个具有不同特征的亚群，其中高度表达耗竭基因的CD4(+)TIGIT(+)亚群（P = 0.007）和CD8(+)LAG3(+)（P = 0.010)亚群明显高于健康对照者。拟时间分析显示，CD4(+)TIGIT(+)亚群和CD8(+)LAG3(+)亚群在T淋巴细胞分化的后期出现，提示T细胞在ACLF发病过程中从幼稚-效应-耗竭的转变。 结论： HBV-ACLF患者外周血T细胞分化存在异质性，以CD4(+)TIGIT(+)T细胞亚群和CD8(+)LAG3(+)T细胞亚群为特征的耗竭T细胞数目明显增加，提示T细胞的免疫耗竭参与HBV-ACLF的免疫功能障碍，为改善ACLF患者免疫功能障碍提供潜在有效的靶点分子。.