Exhaustion of CD8+ T Cells in HBV Infection: Searching for Serological Markers.

OBJECTIVE

Chronic infection of the hepatitis B virus (HBV) is associated with the dysfunction and exhaustion of CD8+ T cells, which are crucial in controlling HBV. While clinical parameters provide insight into the state of HBV infection, the relationship between HBV biochemical parameters and CD8+ T cell exhaustion remains poorly understood. This study aimed to evaluate the expression of activation, exhaustion, and function-related markers in CD8+ T cells of HBV carriers, and to determine the potential of HBV clinical parameters as biomarkers for CD8+ T cell exhaustion.

METHODS

We enrolled 93 patients with HBV and measured the expression levels of CD160, T cell Ig and mucin-domain containing-3 (Tim-3), programmed cell death protein 1 (PD-1), cytotoxic T-lymphocyte antigen 4 (CTLA-4), CD28, CD137, granzyme B, and perforin in CD8+ T cells using flow cytometry. HBV clinical parameters including, HBsAg, HBsAb, HBeAg, HBeAb, HBcAb, HBV DNA load, ALT, AST, ABil, and ALB, were measured in the blood samples.

RESULTS

Patients were divided into two groups, HBV DNA+, and HBV DNA-, based on whether their HBV DNA load was below the test baseline; ALT, AST, and CD160+CD8+ T cell percentages were significantly higher in the HBV DNA+ group than in the HBV DNA- group (P=0.0323; P=0.0072; P=0.0458). However, the granzyme B-expressing CD8+ T cell percentage in the HBV DNA-group was higher than the HBV DNA+ group (P=0.0497). In the HBV DNA+ group, CD160, Tim-3, CD28, and perforin were significantly correlated with ALT, granzyme B was significantly correlated with AST; however, there was no correlation with HBV DNA load.

CONCLUSION

It is possible to infer the level of CD8+ T cell exhaustion in patients with an HBV DNA load >102 copies/mL based on clinical parameters (such as ALT, AST, and ABIL).