ABSTRACT
This systematic review investigates the immunosuppressive environment in HBV-associated hepatocellular carcinoma (HCC), characterized by dysfunctional and exhausted HBV-specific T cells alongside an increased infiltration of HBV-specific CD4+ T cells, particularly regulatory T cells (Tregs). Heightened expression of checkpoint inhibitors, notably PD-1, is linked with disease progression and recurrence, indicating its potential as both a prognostic indicator and a target for immunotherapy. Nevertheless, using PD-1 inhibitors has shown limited effectiveness. In a future perspective, understanding the intricate interplay between innate and adaptive immune responses holds promise for pinpointing predictive biomarkers and crafting novel treatment approaches for HBV-associated HCC.
Subject(s)
Adaptive Immunity , Carcinoma, Hepatocellular , Hepatitis B virus , Liver Neoplasms , Carcinoma, Hepatocellular/immunology , Carcinoma, Hepatocellular/virology , Humans , Liver Neoplasms/immunology , Liver Neoplasms/virology , Hepatitis B virus/immunology , T-Lymphocytes, Regulatory/immunology , Programmed Cell Death 1 Receptor/immunology , Immune Checkpoint Inhibitors/therapeutic use , Immune Checkpoint Inhibitors/pharmacology , Hepatitis B/immunology , Hepatitis B/virology , Hepatitis B/complications , Hepatitis B, Chronic/immunology , Hepatitis B, Chronic/virology , Hepatitis B, Chronic/complications , CD4-Positive T-Lymphocytes/immunology , T-Lymphocytes/immunology , ImmunotherapyABSTRACT
Patients with chronic hepatitis B (CHB) gradually develop T cell exhaustion, and the inhibitory receptor molecule, cytotoxic T-lymphocyte antigen-4 (CTLA-4), may play a role in this phenomenon. This systematic review investigates the role of CTLA-4 in the development of T cell exhaustion in CHB. A systematic literature search was conducted on PubMed and Embase on 31 March 2023 to identify relevant studies. Fifteen studies were included in this review. A majority of the studies investigating CD8+ T cells demonstrated increased expression of CTLA-4 in CHB patients, though one study found this only in HBeAg-positive patients. Three out of four studies investigating the expression of CTLA-4 on CD4+ T cells found upregulation of CTLA-4. Several studies showed constitutive expression of CLTA-4 on CD4+ regulatory T cells. CTLA-4 blockade resulted in heterogeneous responses for all T cell types, as it resulted in increased T cell proliferation and/or cytokine production in some studies, while other studies found this only when combining blockade of CTLA-4 with other inhibitory receptors. Although mounting evidence supports a role of CTLA-4 in T cell exhaustion, there is still insufficient documentation to describe the expression and exact role of CTLA-4 in T cell exhaustion in CHB.
