Alterations in Hepatocellular Carcinoma-Specific Immune Responses Following Hepatitis C Virus Elimination by Direct-Acting Antivirals

Area of Science:

• Hepatology
• Immunology
• Oncology

Background:

• Direct-acting antivirals (DAAs) have transformed hepatitis C virus (HCV) infection treatment.
• The impact of DAAs on hepatocellular carcinoma (HCC) development and associated immune responses is not well understood.

Purpose of the Study:

• To investigate the influence of DAAs on anti-HCC immune responses in HCV-infected patients.
• To elucidate the mechanisms underlying DAA-mediated immune modulation in the context of HCC.

Main Methods:

• Compared immune responses to 19 tumor-associated antigen (TAA)-derived peptides and immune cell profiles before and after DAA treatment in 47 HLA-A24-positive patients.
• Examined relationships between immune responses and phenotypic immune cell changes.

Main Results:

• DAA treatment induced four types of anti-TAA immune responses and significantly altered host immune cell profiles.
• Reduced frequencies of PD-1+CD4+ and PD-1+CD8+ T cells post-DAA treatment correlated with enhanced anti-TAA immune responses.
• The HCV F protein was implicated in increased PD-1+ T cell frequency, which decreased after viral eradication.

Conclusions:

• DAAs modulate host immune responses in HCV patients, potentially affecting HCC development.
• Decreased frequencies of PD-1-expressing CD4+ and CD8+ T cells are a key mechanism by which DAAs alter anti-HCC immunity.