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Joshi SS, Sadler M, Patel NH, Osiowy C, Fonseca K, Coffin CS. Systemic cytokine and viral antigen-specific responses in hepatitis D virus RNA positive versus HDV RNA negative patients. Front Med (Lausanne) 2023; 10:1125139. [PMID: 37877022 PMCID: PMC10591067 DOI: 10.3389/fmed.2023.1125139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 09/25/2023] [Indexed: 10/26/2023] Open
Abstract
Background Hepatitis B virus (HBV)/Hepatitis D Virus (HDV) co-infection increases the risk of severe liver disease compared to HBV mono-infection. Adaptive immune responses to HDV are weakly detectable, and the involvement of innate immunity in the progression of HDV-related liver fibrosis is suggested. We hypothesize that an overall innate immune activation in HBV/HDV co-infection plays a role in liver disease progression and also impacts virus specific T cell response. Methods Sixteen HBV/HDV-co-infected-patients (median age 42y/7F/6 Asian/4 White/6 Black/15 HBeAg-) and 8 HBV monoinfected-patients (median age 39y/4F/4 Asian/3 Black/1 White/HBeAg-) with median follow-up of 5 years were enrolled. Liver fibrosis was assessed by liver stiffness measurement (LSM, FibroScan®). Proliferation of CD3 + CD4+ T cells in response to viral antigens using CFSE assays and cytokine secreting monocytes was analyzed by flow cytometry. Results Of 16 HBV/HDV, 11 were HDV-RNA+ (HBV-DNA 0-1,040 IU/mL), 5/11 Interferon (IFN) + Nucleos/tide Analog (NA), 3/11 NA monotherapy, median ALT 77 U/L at the time of sample collection, median LSM of 9.8. In 5 HDV RNA-, median HBV DNA 65 IU/mL, 4/5 prior IFN and/or NA, ALT 31 U/L, and median LSM 8.5 kPa. In 8 HBV controls, median HBV-DNA, ALT, LSM was 69 IU/mL, 33 U/L,5 kPa, respectively. PBMC stimulation with HBV core antigen (HBcAg) and HDV antigen (HDAg) showed weaker CD3 + CD4 + T-cell proliferation in HDV-RNA+ vs. HDV RNA- and HBV-mono-infected patients (p < 0.05). In HDV-RNA+ patients, a correlation between ALT and TNF-α (r = 0.76, p = 0.008), higher IL-10 levels and increased proportion of CD14 + TNF-α+ cells were found. Conclusion In summary, during HBV/HDV coinfection, HDV RNA+ patients had weaker HBV and HDV specific responses, associated with increased TNF-α + monocytes irrespective of IFN treatment.
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Affiliation(s)
- Shivali S. Joshi
- Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Matthew Sadler
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Nishi H. Patel
- Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Carla Osiowy
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | - Kevin Fonseca
- Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Carla S. Coffin
- Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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2
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Lopez-Scarim J, Nambiar SM, Billerbeck E. Studying T Cell Responses to Hepatotropic Viruses in the Liver Microenvironment. Vaccines (Basel) 2023; 11:681. [PMID: 36992265 PMCID: PMC10056334 DOI: 10.3390/vaccines11030681] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/19/2023] Open
Abstract
T cells play an important role in the clearance of hepatotropic viruses but may also cause liver injury and contribute to disease progression in chronic hepatitis B and C virus infections which affect millions of people worldwide. The liver provides a unique microenvironment of immunological tolerance and hepatic immune regulation can modulate the functional properties of T cell subsets and influence the outcome of a virus infection. Extensive research over the last years has advanced our understanding of hepatic conventional CD4+ and CD8+ T cells and unconventional T cell subsets and their functions in the liver environment during acute and chronic viral infections. The recent development of new small animal models and technological advances should further increase our knowledge of hepatic immunological mechanisms. Here we provide an overview of the existing models to study hepatic T cells and review the current knowledge about the distinct roles of heterogeneous T cell populations during acute and chronic viral hepatitis.
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Affiliation(s)
| | | | - Eva Billerbeck
- Division of Hepatology, Department of Medicine and Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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3
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Hepatitis B and Hepatitis D Viruses: A Comprehensive Update with an Immunological Focus. Int J Mol Sci 2022; 23:ijms232415973. [PMID: 36555623 PMCID: PMC9781095 DOI: 10.3390/ijms232415973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/08/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Hepatitis B virus (HBV) and hepatitis delta virus (HDV) are highly prevalent viruses estimated to infect approximately 300 million people and 12-72 million people worldwide, respectively. HDV requires the HBV envelope to establish a successful infection. Concurrent infection with HBV and HDV can result in more severe disease outcomes than infection with HBV alone. These viruses can cause significant hepatic disease, including cirrhosis, fulminant hepatitis, and hepatocellular carcinoma, and represent a significant cause of global mortality. Therefore, a thorough understanding of these viruses and the immune response they generate is essential to enhance disease management. This review includes an overview of the HBV and HDV viruses, including life cycle, structure, natural course of infection, and histopathology. A discussion of the interplay between HDV RNA and HBV DNA during chronic infection is also included. It then discusses characteristics of the immune response with a focus on reactions to the antigenic hepatitis B surface antigen, including small, middle, and large surface antigens. This paper also reviews characteristics of the immune response to the hepatitis D antigen (including small and large antigens), the only protein expressed by hepatitis D. Lastly, we conclude with a discussion of recent therapeutic advances pertaining to these viruses.
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4
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Salpini R, D'Anna S, Piermatteo L, Svicher V. Novel concepts on mechanisms underlying Hepatitis Delta virus persistence and related pathogenesis. J Viral Hepat 2022; 29:1038-1047. [PMID: 36256499 DOI: 10.1111/jvh.13755] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/07/2022] [Indexed: 12/09/2022]
Abstract
Hepatitis Delta virus is the smallest known human virus, exploiting the HBV surface proteins (HBsAg) for the release of its progeny and de novo entry into hepatocytes. Ever growing evidence have highlighted the existence of multiple mechanisms underlying HDV persistence including integrated HBV-DNA as a source of HBsAg production and the capability of the HDV genome to propagate through cell proliferation, thus supporting a potential HDV persistence even in the absence of HBV. Chronic HDV-infection causes the most severe form of viral hepatitis, leading to the development of cirrhosis in 15% of cases within 1-2 years and in 50%-60% of cases within 5-10 years. The rates of hepatocellular carcinoma and hepatic decompensation are also 2-3-fold higher than for HBV mono-infection. There is the evidence that persistent viral replication plays a key role in triggering liver injury, suggesting the existence of direct viral cytopathic properties that can modulate, synergistically with immune-responses, the progression towards end-stage liver diseases. All these aspects can be further exacerbated by the extraordinary degree of viral genetic variability that can promote HDV evasion from immune responses and has enabled viral differentiation into genotypes and subgenotypes with potential different pathobiological properties. In this light, this review aims at providing comprehensive insights of mechanisms (with a focus on virological factors) underlying HDV persistence and pathogenesis, critical in shaping the clinical outcome of the infection. Dissecting these mechanisms is pivotal to optimize therapeutic strategies aimed at fully counteracting this fascinating and fearsome virus.
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Affiliation(s)
- Romina Salpini
- Department of Experimental Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Stefano D'Anna
- Department of Experimental Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Lorenzo Piermatteo
- Department of Experimental Medicine, University of Rome Tor Vergata, Rome, Italy.,Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | - Valentina Svicher
- Department of Experimental Medicine, University of Rome Tor Vergata, Rome, Italy.,Department of Biology, University of Rome Tor Vergata, Rome, Italy
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5
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Li Q, Sun B, Zhuo Y, Jiang Z, Li R, Lin C, Jin Y, Gao Y, Wang D. Interferon and interferon-stimulated genes in HBV treatment. Front Immunol 2022; 13:1034968. [PMID: 36531993 PMCID: PMC9751411 DOI: 10.3389/fimmu.2022.1034968] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 11/09/2022] [Indexed: 12/04/2022] Open
Abstract
Human hepatitis B virus (HBV) is a small enveloped DNA virus with a complex life cycle. It is the causative agent of acute and chronic hepatitis. HBV can resist immune system responses and often causes persistent chronic infections. HBV is the leading cause of liver cancer and cirrhosis. Interferons (IFNs) are cytokines with antiviral, immunomodulatory, and antitumor properties. IFNs are glycoproteins with a strong antiviral activity that plays an important role in adaptive and innate immune responses. They are classified into three categories (type I, II, and III) based on the structure of their cell-surface receptors. As an effective drug for controlling chronic viral infections, Type I IFNs are approved to be clinically used for the treatment of HBV infection. The therapeutic effect of interferon will be enhanced when combined with other drugs. IFNs play a biological function by inducing the expression of hundreds of IFN-stimulated genes (ISGs) in the host cells, which are responsible for the inhibiting of HBV replication, transcription, and other important processes. Animal models of HBV, such as chimpanzees, are also important tools for studying IFN treatment and ISG regulation. In the present review, we summarized the recent progress in IFN-HBV treatment and focused on its mechanism through the interaction between HBV and ISGs.
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Affiliation(s)
- Qirong Li
- Department of Gastrointestinal Colorectal and Anal Surgery, China-Japan Union Hospital of Jilin University, Changchun, China,Laboratory Animal Center, College of Animal Science, Jilin University, Changchun, China
| | - Baozhen Sun
- Department of Hepatobiliary and Pancreas Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Yue Zhuo
- School of Acupuncture-Moxi bustion and Tuina, Changchun University of Chinese Medicine, Changchun, China
| | - Ziping Jiang
- Department of Hand and Foot Surgery, The First Hospital of Jilin University, Changchun, China
| | - Rong Li
- Laboratory Animal Center, College of Animal Science, Jilin University, Changchun, China
| | - Chao Lin
- School of Grain Science and Technology, Jilin Business and Technology College, Changchun, China
| | - Ye Jin
- School of Pharmacy, Changchun University of Chinese Medicine, Changchun, China
| | - Yongjian Gao
- Department of Gastrointestinal Colorectal and Anal Surgery, China-Japan Union Hospital of Jilin University, Changchun, China,*Correspondence: Yongjian Gao, ; Dongxu Wang,
| | - Dongxu Wang
- Laboratory Animal Center, College of Animal Science, Jilin University, Changchun, China,*Correspondence: Yongjian Gao, ; Dongxu Wang,
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6
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Zai W, Hu K, Ye J, Ding J, Huang C, Li Y, Fang Z, Wu M, Wang C, Chen J, Yuan Z. Long-Term Hepatitis B Virus Infection Induces Cytopathic Effects in Primary Human Hepatocytes, and Can Be Partially Reversed by Antiviral Therapy. Microbiol Spectr 2022; 10:e0132821. [PMID: 35171034 PMCID: PMC8849052 DOI: 10.1128/spectrum.01328-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 01/21/2022] [Indexed: 01/05/2023] Open
Abstract
Chronic infection of hepatitis B virus (HBV) remains a major health burden worldwide. While the immune response has been recognized to play crucial roles in HBV pathogenesis, the direct cytopathic effects of HBV infection and replication on host hepatocytes and the HBV-host interactions are only partially defined due to limited culture systems. Here, based on our recently developed 5 chemical-cultured primary human hepatocytes (5C-PHHs) model that supports long-term HBV infection, we performed multiplexed quantitative analysis of temporal changes of host proteome and transcriptome on PHHs infected by HBV for up to 4 weeks. We showed that metabolic-, complement-, cytoskeleton-, mitochondrial-, and oxidation-related pathways were modulated at transcriptional or posttranscriptional levels during long-term HBV infection, which led to cytopathic effects and could be partially rescued by early, rather than late, nucleot(s)ide analog (NA) administration and could be significantly relieved by blocking viral antigens with RNA interference (RNAi). Overexpression screening of the dysregulated proteins identified a series of host factors that may contribute to pro- or anti-HBV responses of the infected hepatocytes. In conclusion, our results suggest that long-term HBV infection in primary human hepatocytes leads to cytopathic effects through remodeling the proteome and transcriptome and early antiviral treatment may reduce the extent of such effects, indicating a role of virological factors in HBV pathogenesis and a potential benefit of early administration of antiviral treatment. IMPORTANCE Global temporal quantitative proteomic and transcriptomic analysis using long-term hepatitis B virus (HBV)-infected primary human hepatocytes uncovered extensive remodeling of the host proteome and transcriptome and revealed cytopathic effects of long-term viral replication. Metabolic-, complement-, cytoskeleton-, mitochondrial-, and oxidation-related pathways were modulated at transcriptional or posttranscriptional levels, which could be partially rescued by early, rather than late, NA therapy and could be relieved by blocking viral antigens with RNAi. Overexpression screening identified a series of pro- or anti-HBV host factors. These data have deepened the understanding of the mechanisms of viral pathogenesis and HBV-host interactions in hepatocytes, with implications for therapeutic intervention.
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Affiliation(s)
- Wenjing Zai
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
| | - Kongying Hu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jianyu Ye
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jiahui Ding
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
| | - Chao Huang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yaming Li
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
| | - Zhong Fang
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Min Wu
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Cong Wang
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Jieliang Chen
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
- Research Unit of Cure of Chronic Hepatitis B Virus Infection, Chinese Academy of Medical Sciences, Shanghai, China
| | - Zhenghong Yuan
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
- Research Unit of Cure of Chronic Hepatitis B Virus Infection, Chinese Academy of Medical Sciences, Shanghai, China
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7
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Kefalakes H, Horgan XJ, Jung MK, Amanakis G, Kapuria D, Bolte FJ, Kleiner DE, Koh C, Heller T, Rehermann B. Liver-Resident Bystander CD8 + T Cells Contribute to Liver Disease Pathogenesis in Chronic Hepatitis D Virus Infection. Gastroenterology 2021; 161:1567-1583.e9. [PMID: 34302839 DOI: 10.1053/j.gastro.2021.07.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 06/29/2021] [Accepted: 07/13/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS The hepatitis D virus (HDV) causes the most severe form of chronic hepatitis, often progressing to cirrhosis within 5 to 10 years. There is no curative treatment, and the mechanisms underlying the accelerated liver disease progression are unknown. METHODS Innate and adaptive immune responses were studied in blood and liver of 24 patients infected with HDV and 30 uninfected controls by multiparameter flow cytometry in correlation with disease severity and stage. RESULTS The 2 main intrahepatic innate immune-cell populations, mucosal-associated invariant T cells and natural killer (NK) cells, were reduced in the livers of patients infected with HDV compared with those of uninfected controls but were more frequently activated in the liver compared with the blood. Most intrahepatic cluster of differentiation (CD) 8-positive (CD8+) T cells were memory cells or terminal effector memory cells, and most of the activated and degranulating (CD107a+) HDV-specific and total CD8+ T cells were liver-resident (CD69+C-X-C motif chemokine receptor 6+). Unsupervised analysis of flow cytometry data identified an activated, memory-like, tissue-resident HDV-specific CD8+ T-cell cluster with expression of innate-like NK protein 30 (NKp30) and NK group 2D (NKG2D) receptors. The size of this population correlated with liver enzyme activity (r = 1.0). NKp30 and NKG2D expression extended beyond the HDV-specific to the total intrahepatic CD8+ T-cell population, suggesting global bystander activation. This was supported by the correlations between (i) NKG2D expression with degranulation of intrahepatic CD8+ T cells, (ii) frequency of degranulating CD8+ T cells with liver enzyme activity and the aspartate aminotransferase-to-platelet ratio index score, and by the in vitro demonstration of cytokine-induced NKG2D-dependent cytotoxicity. CONCLUSION Antigen-nonspecific activation of liver-resident CD8+ T cells may contribute to inflammation and disease stage in HDV infection.
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Affiliation(s)
- Helenie Kefalakes
- Immunology Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Xylia J Horgan
- Immunology Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Min Kyung Jung
- Immunology Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Georgios Amanakis
- Laboratory of Cardiac Physiology, Cardiovascular Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Devika Kapuria
- Clinical Research Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Fabian J Bolte
- Immunology Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - David E Kleiner
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Christopher Koh
- Clinical Research Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Theo Heller
- Translational Hepatology Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland
| | - Barbara Rehermann
- Immunology Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland.
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Vachon A, Osiowy C. Novel Biomarkers of Hepatitis B Virus and Their Use in Chronic Hepatitis B Patient Management. Viruses 2021; 13:951. [PMID: 34064049 PMCID: PMC8224022 DOI: 10.3390/v13060951] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 12/15/2022] Open
Abstract
Even though an approved vaccine for hepatitis B virus (HBV) is available and widely used, over 257 million individuals worldwide are living with chronic hepatitis B (CHB) who require monitoring of treatment response, viral activity, and disease progression to reduce their risk of HBV-related liver disease. There is currently a lack of predictive markers to guide clinical management and to allow treatment cessation with reduced risk of viral reactivation. Novel HBV biomarkers are in development in an effort to improve the management of people living with CHB, to predict disease outcomes of CHB, and further understand the natural history of HBV. This review focuses on novel HBV biomarkers and their use in the clinical setting, including the description of and methodology for quantification of serum HBV RNA, hepatitis B core-related antigen (HBcrAg), quantitative hepatitis B surface antigen (qHBsAg), including ultrasensitive HBsAg detection, quantitative anti-hepatitis B core antigen (qAHBc), and detection of HBV nucleic acid-related antigen (HBV-NRAg). The utility of these biomarkers in treatment-naïve and treated CHB patients in several clinical situations is further discussed. Novel HBV biomarkers have been observed to provide critical clinical information and show promise for improving patient management and our understanding of the natural history of HBV.
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Affiliation(s)
- Alicia Vachon
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3E 0J9, Canada;
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB R3E 3R2, Canada
| | - Carla Osiowy
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3E 0J9, Canada;
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB R3E 3R2, Canada
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Abstract
HDV is a small, defective RNA virus that requires the HBsAg of HBV for its assembly, release, and transmission. Chronic HBV/HDV infection often has a severe clinical outcome and is difficult to treat. The important role of a robust virus-specific T cell response for natural viral control has been established for many other chronic viral infections, but the exact role of the T cell response in the control and progression of chronic HDV infection is far less clear. Several recent studies have characterised HDV-specific CD4+ and CD8+ T cell responses on a peptide level. This review comprehensively summarises all HDV-specific T cell epitopes described to date and describes our current knowledge of the role of T cells in HDV infection. While we now have better tools to study the adaptive anti-HDV-specific T cell response, further efforts are needed to define the HLA restriction of additional HDV-specific T cell epitopes, establish additional HDV-specific MHC tetramers, understand the degree of cross HDV genotype reactivity of individual epitopes and understand the correlation of the HBV- and HDV-specific T cell response, as well as the breadth and specificity of the intrahepatic HDV-specific T cell response.
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Key Words
- ADAR1, adenosine deaminases acting on RNA
- ALT, alanine aminotransferase
- AST, aspartate aminotransferase
- CD4+
- CD8+
- ELISpot, enzyme-linked immune spot assay
- HBV
- HDAg, hepatitis delta antigen
- HDV
- Hepatitis Delta
- ICS, intracellular cytokine staining
- IFN-, interferon-
- L-HDAg, large hepatitis delta antigen
- MAIT, mucosa-associated invariant T cells
- NK cells, natural killer cells
- NTCP, sodium taurocholate co-transporting polypeptide
- PBMCs, peripheral blood mononuclear cells
- PD-1, programmed cell death protein 1
- PTM, post-translational modification
- Peg-IFN-α, pegylated interferon alpha
- S-HDAg, small hepatitis delta antigen
- T cell
- TCF, T cell-specific transcription factor
- TNFα, tumour necrosis factor-α
- Th1, T helper 1
- aa, amino acid(s)
- cccDNA, covalently closed circular DNA
- epitope
- viral escape
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In Vivo Models of HDV Infection: Is Humanizing NTCP Enough? Viruses 2021; 13:v13040588. [PMID: 33807170 PMCID: PMC8065588 DOI: 10.3390/v13040588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 03/26/2021] [Accepted: 03/28/2021] [Indexed: 12/28/2022] Open
Abstract
The discovery of sodium taurocholate co-transporting polypeptide (NTCP) as a hepatitis B (HBV) and delta virus (HDV) entry receptor has encouraged the development of new animal models of infection. This review provides an overview of the different in vivo models that are currently available to study HDV either in the absence or presence of HBV. By presenting new advances and remaining drawbacks, we will discuss human host factors which, in addition to NTCP, need to be investigated or identified to enable a persistent HDV infection in murine hepatocytes. Detailed knowledge on species-specific factors involved in HDV persistence also shall contribute to the development of therapeutic strategies.
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