The Expression of Programmed Death-1 in Circulating CD4+ and CD8+ T Cells during Hepatitis B Virus Infection Progression and Its Correlation with Clinical Baseline Characteristics

BACKGROUND/AIMS Programmed death-1 (PD-1) expression was investigated in CD4(+) and CD8(+) T cells from hepatitis B virus (HBV)-infected patients at the chronic hepatitis B (CHB) infection, liver cirrhosis (LC), and hepatocellular carcinoma (HCC) stages. METHODS PD-1 expression in circulating CD4(+) and CD8(+) T cells was detected by flow cytometry. The correlations between PD-1 expression and HBV viral load, alanine aminotransaminase (ALT) levels and aspartate aminotransferase (AST) levels were analyzed using GraphPad Prism 5.0. RESULTS PD-1 expression in CD4(+) and CD8(+) T cells was significantly increased in both the CHB group and advanced-stage group (LC plus HCC). In the CHB group, PD-1 expression in both CD4(+) and CD8(+) T cells was positively correlated with the HBV viral load, ALT, and AST levels. However, in the LC plus HCC group, significant correlations between PD-1 expression and the clinical parameters were nearly absent. CONCLUSIONS PD-1 expression in peripheral CD4(+) and CD8(+) T cells is dynamic, changes with HBV infection progression, and is related to HBV viral load and liver function, especially in CHB. PD-1 expression could be utilized as a potential clinical indicator to determine the extent of virus replication and liver injury.