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Background/Aims@#The occurrence and development of hepatitis B virus-associated acute-onchronic liver failure (HBV-ACLF) is closely related to the immune pathway. We explored the heterogeneity of peripheral blood T cell subsets and the characteristics of exhausted T lymphocytes, in an attempt to identify potential therapeutic target molecules for immune dysfunction in ACLF patients. @*Methods@#A total of 83,577 T cells from HBV-ACLF patients and healthy controls were screened for heterogeneity by single-cell RNA sequencing. In addition, exhausted T-lymphocyte subsets were screened to analyze their gene expression profiles, and their developmental trajectories were investigated. Subsequently, the expression of exhausted T cells and their capacity in secreting cytokines (interleukin 2, interferon γ, and tumor necrosis factor α) were validated by flow cytometry. @*Results@#A total of eight stable clusters were identified, among which CD4 + TIGIT + subset and CD8 + LAG-3 + subset, with high expression of exhaust genes, were significantly higher in the HBV-ACLF patients than in normal controls. As shown by pseudotime analysis, T cells experienced a transition from naïve T cells to effector T cells and then exhausted T cells. Flow cytometry confirmed that the CD4 + TIGIT + subset and CD8 + LAG-3 + subset in the peripheral blood of the ACLF patients were significantly higher than those in the healthy controls. Moreover, in vitro cultured CD8 + LAG-3 + T cells were significantly fewer capable of secreting cytokines than CD8 + LAG-3- subset. @*Conclusions@#Peripheral blood T cells are heterogeneous in HBV-ACLF. The exhausted T cells markedly increase during the pathogenesis of ACLF, suggesting that T-cell exhaustion is involved in the immune dysfunction of HBV-ACLF patients.
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Objective:To observe the antagonism of dexamethasone on radiation bystander effect and its re-transmission in rabbit lymphocytes.Methods:The plasmas of 2 New Zealand rabbits which were irradiated with 6 MV X-ray was taken to prepare the first generation of conditioned medium; the plasmas of 2 unirradiated New Zealand rabbits were taken to prepare the first generation of unconditioned culture medium; The lymphocytes of 5 unirradiated New Zealand rabbits were extracted. The lymphocytes from 5 unirradiated New Zealand rabbits were cocultured with the first generation of unconditioned medium or conditioned medium. After abandoning the culture medium, the lymphocytes were cultured in conventional medium for 24 h. The second generation of unconditioned medium or conditioned medium was taken. The lymphocytes were treated with four medium with or without dexamethasone (1 μg/ml), and the apoptosis rate of lymphocytes was detected by flow cytometry.Results:With or without dexamethasone, the apoptosis rates of lymphocytes treated with the first generation of conditioned medium was significantly higher than that with the first generation of unconditioned medium [without dexamethasone: (21.09±1.60)% vs. (8.06±0.65)%, t = -30.182, P < 0.05; with dexamethasone: (14.96±1.80)% vs. (6.25±0.54)%, t = -16.404, P < 0.05]. Dexamethasone could reduce the apoptosis rates of lymphocytes treated with the first generation of unconditioned medium and the first generation of conditioned medium, and the differences were statistically significant (both P < 0.05). With or without dexamethasone, the apoptosis rates of lymphocytes treated with the second generation of conditioned medium was significantly higher than that with the second generation of unconditioned medium [without dexamethasone: (28.70±2.14)% vs. (12.38±0.67)%, t = -33.351, P < 0.05; with dexamethasone: (20.21±1.96)% vs. (12.53±1.25)%, t = -14.145, P < 0.05]. Dexamethasone could reduce the apoptosis rates of lymphocytes treated with the second generation of conditioned medium ( P < 0.05), but it could not reduce the apoptosis rate of lymphocytes treated with the second generation of unconditioned medium ( P > 0.05). Conclusion:Dexamethasone can antagonize the injury of lymphocytes by radiation bystander effect in vitro, reduce the apoptosis rate of lymphocytes, and can also antagonize the re-transmission of radiation bystander effect.
