Hepatitis B virus induces T cell exhaustion by increasing mitochondrial ROS accumulation

Area of Science:

• Immunology
• Hepatology
• Cellular Biology

Background:

• Chronic hepatitis B (CHB) is a significant global health concern.
• T cell dysfunction plays a critical role in viral persistence and disease progression in CHB.
• Mitochondrial dysfunction and reactive oxygen species (ROS) are implicated in various chronic inflammatory conditions.

Purpose of the Study:

• To investigate the levels of mitochondrial ROS in T cells from CHB patients.
• To explore the relationship between ROS, viral load, and T cell exhaustion markers (PD-1).
• To assess the impact of ROS on immune function, specifically interferon-gamma (IFN-γ) production.

Main Methods:

• Prospective analysis of 95 participants (72 CHB patients, 23 healthy controls).
• Quantification of serum HBV-DNA levels.
• Flow cytometry to measure mitochondrial ROS and PD-1 expression in T cells (CD8+ and CD4+).
• ELISA to determine plasma IFN-γ levels.

Main Results:

• Elevated ROS levels in CD8+ and CD4+ T cells positively correlated with HBV-DNA load.
• CHB patients showed increased PD-1 expression on T cells compared to healthy controls.
• ROS levels were higher in PD-1 expressing T cells.
• Plasma IFN-γ levels were inversely associated with HBV-DNA load and CD8+ T cell ROS production.

Conclusions:

• Increased mitochondrial ROS in T cells is associated with higher viral loads in CHB.
• ROS accumulation coincides with T cell exhaustion (PD-1 upregulation) and reduced IFN-γ.
• Mitochondrial dysfunction is a potential driver of T cell exhaustion in chronic hepatitis B.