Objective       To explore the proportion of TCR γδT (γδT) cells and the cytokine production ability of the γδT cells in peripheral blood of patients with h

epatitis B virus-associated acute-on-chronic liver failure (HBV-ACLF)

and to analyze the correlation between the proportion of cells and the clinical parameters.       Methods       Twenty-six patients with HBV-ACLF (HBV-ACLF group)

40 patients with chronic HBV infection (CHBV group)

and 25 healthy controls (HC group) were enrolled in this study. The proportion of γδT cells in peripheral blood of the subjects and the proportion of IFN-γ

TNF-α

or IL-17 producing γδT cells were determined by flow cytometry. The differences of the proportion of cytokine-producing γδT cells among the three groups and the correlation of the proportion with clinical parameters were statistically analyzed by SPSS software.       Results       The proportion of γδT cells in peripheral blood of the HBV-ACLF group (4.8% as median) was significantly lower than that of the CHBV group (10.7% as median) and HC group (10.3% as median) (P0.01). After stimulation

the proportion of IFN-γ

+

γδT cells in the HBV-ACLF group (73.9% as median) and CHBV group (70.9% as median) was significantly higher than that in the HC group (45.3% as median) (P0.01). The proportions of TNF-α

+

γδT cells and IL-17

+

γδT cells (26.7% and 0.7% as median) were significantly higher in the HBV-ACLF group than in the CHBV group (11.5% and 0.3%) and HC group (11.7% and 0.3%) (P0.01). Moreover

the proportion of TNF-α

+

γδT cells was negatively correlated with the levels of ALT and AST.       Conclusion       Although the proportion of total γδT cells in peripheral blood of HBV-ACLF patients decreases

the ability of the γδT cells in producing IFN-γ

TNF-α and IL-17 is enhanced

which may be involved in the acute systemic inflammatory responses in HBV-ACLF development.