Hepatitis B virus-specific effector CD8⁺ T cells are an important determinant of disease prognosis: A meta-analysis

Background: Hepatitis B virus (HBV)-specific effector CD8⁺ T cells are critical for viral clearance. To determine the effects of HBV-specific effector CD8⁺ T cells on HBV infection, we performed a meta-analysis of the available literature.

Methods: Electronic database searches identified appropriately designed studies that detected specific CD8⁺ T cells in HBV-infected patients. Our main endpoints were the course of infection, seroconversion of HBV "e" antigen (HBeAg), the level of HBVDNA, and alanine aminotransferase (ALT) activity. We used a fixed/random model for analysis, according to the results of a heterogeneity test (P value of Q-squared, I²).

Results: Our searches found five eligible articles. Pooled estimation of the reported results showed that levels of specific CD8⁺ T cells were significantly higher in patients with acute hepatitis B than in patients with chronic hepatitis B (odds ratio [OR] = 76.30, 95% confidence interval [CI]: 15.37-378.70). With respect to chronic hepatitis B, patients with <10⁷ copies/ml HBVDNA had higher levels of specific CD8⁺ T cells relative to patients with >10⁷ copies/ml HBVDNA, but the difference had no statistics significance (OR: 3.89, 95% CI: 0.71-21.33). Patients with negative HBeAg or positive anti-HBeAg antibody (anti-HBe) results had significantly higher levels of specific CD8⁺ T cells versus patients with positive HBeAg results (OR: 5.82, 95% CI: 1.41-24.13). There were no significant associations between the levels of specific CD8⁺ T cells and serum ALT activity (OR = 0.86, 95% CI: 0.01-74.15).

Conclusion: HBV-specific effector CD8⁺ T cells influence the disease activity in HBV-infected patients in various ways and determine prognosis by eliminating the virus. Therefore, efforts of studying HBV-specific effector CD8⁺ T cells focused vaccine are potentially needed.