Evolving therapies in the treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. The major etiologies and risk factors for HCC development are well defined and some of the steps involved in hepatocarcinogenesis have been elucidated in recent years. Therapeutic options that can be applied in curative or palliative intention are available and are dependent on the HCC stage. The therapeutic options fall into five main categories: (1) surgical interventions, including tumor resection and liver transplantation, (2) percutaneous interventions, including ethanol injection and radiofrequency thermal ablation, (3) transarterial interventions, including embolization and chemoembolization, (4) radiation therapy, and (5) drugs as well as gene and immune therapies. Until recently, no therapy existed for patients with advanced HCC. In 2007 a multikinase inhibitor (sorafenib) showed for the first time a significant increase in overall survival in patients with advanced HCC. Furthermore, several other agents that target different factors of hepatocarcinogenesis (eg, epidermal growth factor, insulin-like growth factors, hepatocyte growth factor, vascular endothelial growth factor, fibroblast growth factor, platelet-derived growth factor, and the transforming growth factors-α and -β), have emerged and been tested in clinical trials. This review gives an overview of the current therapeutic strategies and their clinical impact

Tetramer enrichment reveals the presence of phenotypically diverse hepatitis C virus-specific CD8+T cells in chronic infection

Virus-specific CD8+ T cells are rarely detectable ex vivo by conventional methods during chronic hepatitis C virus (HCV) infection. In this study, however, we were able to detect and characterize HCV-specific CD8+ T cells in all chronically HCV genotype 1a-infected, HLA-A*02:01-positive patients analyzed by performing major histocompatibility complex (MHC) class I tetramer enrichment. Two-thirds of these enriched HCV-specific CD8+ T-cell populations displayed an effector memory phenotype, whereas, surprisingly, one-third displayed a naive-like phenotype despite ongoing viral replication. CD8+ T cells with an effector memory phenotype could not expand in vitro, suggesting exhaustion of these cells. Interestingly, some of the naive-like CD8+ T cells proliferated vigorously upon in vitro priming, whereas others did not. These differences were linked to the corresponding viral sequences in the respective patients. Indeed, naive-like CD8+ T cells from patients with the consensus sequence in the corresponding T-cell epitope did not expand in vitro. In contrast, in patients displaying sequence variations, we were able to induce HCV-specific CD8+ T-cell proliferation, which may indicate infection with a variant virus. Collectively, these data reveal the presence of phenotypically and functionally diverse HCV-specific CD8+ T cells at very low frequencies that are detectable in all chronically infected patients despite viral persistence. IMPORTANCE In this study, we analyzed CD8+ T-cell responses specific for HLA-A*02:01-restricted epitopes in chronically HCV-infected patients, using MHC class I tetramer enrichment. Importantly, we could detect HCV-specific CD8+ T-cell populations in all patients. To further characterize these HCV-specific CD8+ T-cell populations that are not detectable using conventional techniques, we performed phenotypic, functional, and viral sequence analyses. These data revealed different mechanisms for CD8+ T-cell failure in HCV infection, including T-cell exhaustion, viral escape, and functional impairment of naive-like HCV-specific CD8+ T cells

Ischemic Duodenal Ulceration after Transarterial Chemoembolization for Hepatocellular Carcinoma: A Case Report

Drug-eluting bead transarterial chemoembolization (DEB-TACE) is a well-established, minimally invasive interventional treatment for nonresectable hepatocellular carcinoma (HCC). Generally, TACE is regarded as safe and effective with a low complication rate. However, remote gastrointestinal ischemia due to the carryover of embolic material into visceral arteries is a rare but serious complication of TACE. In this report, we present a case of duodenal ulceration with contained perforation and severe necrotizing pancreatitis after TACE in a patient with nonresectable HCC and underlying hepatitis C virus associated with Child-Pugh stage B liver cirrhosis. This patient showed, for the first time, complete endoscopic and clinical recovery within 2 months of conservative treatment. Considering the high mortality rate from surgical intervention in all previously reported patients, the significant recovery potential demonstrated by our case suggests conservative treatment with antibiotics and parenteral nutrition combined with close clinical, radiological, and endoscopic monitoring should be considered in all clinically stable patients without signs of peritonism or septic sequelae

Role of Host Genetic Factors in the Outcome of Hepatitis C Virus Infection

The natural history of hepatitis C virus (HCV) infection is determined by a complex interplay between host genetic, immunological and viral factors. This review highlights genes involved in innate and adaptive immune responses associated with different outcomes of HCV infection. For example, an association of HCV clearance with certain HLA alleles has been demonstrated. The mechanisms responsible for these associations have been linked to specific T cell responses for some particular alleles (e.g., HLA-B27). Genetic associations involved in T cell regulation and function further underline the role of the adaptive immune response in the natural history of HCV infection. In addition, some genes involved in innate NK cell responses demonstrate the complex interplay between components of the immune system necessary for a successful host response to HCV infection

Within-host evolution of SARS-CoV-2 in an immunosuppressed COVID-19 patient as a source of immune escape variants.

The origin of SARS-CoV-2 variants of concern remains unclear. Here, we test whether intra-host virus evolution during persistent infections could be a contributing factor by characterizing the long-term SARS-CoV-2 infection dynamics in an immunosuppressed kidney transplant recipient. Applying RT-qPCR and next-generation sequencing (NGS) of sequential respiratory specimens, we identify several mutations in the viral genome late in infection. We demonstrate that a late viral isolate exhibiting genome mutations similar to those found in variants of concern first identified in UK, South Africa, and Brazil, can escape neutralization by COVID-19 antisera. Moreover, infection of susceptible mice with this patient's escape variant elicits protective immunity against re-infection with either the parental virus and the escape variant, as well as high neutralization titers against the alpha and beta SARS-CoV-2 variants, B.1.1.7 and B.1.351, demonstrating a considerable immune control against such variants of concern. Upon lowering immunosuppressive treatment, the patient generated spike-specific neutralizing antibodies and resolved the infection. Our results suggest that immunocompromised patients could be a source for the emergence of potentially harmful SARS-CoV-2 variants

Immunodominance of HLA-A2-restricted hepatitis C virus-specific CD8+ T cell responses is linked to naive-precursor frequency

The impact of naïve precursor frequency on human virus-specific CD8+ T cell immunodominance is not well understood. Using a recently developed MHC class I tetramer enrichment protocol, we found a conserved hierarchy and >10-fold difference in naïve precursor frequencies across three HLA-A2 restricted HCV-specific epitopes. Importantly, the NS31406 epitope with the highest naïve precursor frequency in healthy donors was also the most frequently targeted epitope in a large cohort of chronically HCV-infected patients, both ex vivo and after in vitro stimulation. These results indicate for the first time that immunodominance in a human viral infection is linked to naïve precursor frequency

TOX defines the degree of CD8+ T cell dysfunction in distinct phases of chronic HBV infection

Objective Chronic hepatitis B virus (HBV) infection is characterised by HBV-specific CD8+ T cell dysfunction that has been linked to Tcell exhaustion, a distinct differentiation programme associated with persisting antigen recognition. Recently, Thymocyte Selection-Associated High Mobility Group Box (TOX) was identified as master regulator of CD8+ T cell exhaustion. Here, we addressed the role of TOX in HBV-specific CD8+ T cell dysfunction associated with different clinical phases of infection. Design We investigated TOX expression in HBV-specific CD8+ T cells from 53 HLA-A*01:01, HLA-A*11:01 and HLA-A*02:01 positive patients from different HBV infection phases and compared it to hepatitis C virus (HCV)-specific, cytomegalovirus (CMV)-specific, Epstein-Barr virus (EBV)-specific and influenza virus (FLU)-specific CD8+ T cells. Phenotypic and functional analyses of virus-specific CD8+ T cells were performed after peptide-loaded tetramer-enrichment and peptide-specific expansion. Results Our results show that TOX expression in HBV-specific CD8+ T cells is linked to chronic antigen stimulation, correlates with viral load and is associated with phenotypic and functional characteristics of T-cell exhaustion. In contrast, similar TOX expression in EBV-specific and CMV-specific CD8+ T cells is not linked to T-cell dysfunction suggesting different underlying programmes. TOX expression in HBV-specific CD8+ T cells is also affected by targeted antigens, for example, core versus polymerase. In HBV-specific CD8+ T cells, TOX expression is maintained after spontaneous or therapy-mediated viral control in chronic but not self-limiting acute HBV infection indicating a permanent molecular imprint after chronic but not temporary stimulation. Conclusion Our data highlight TOX as biomarker specific for dysfunctional virus-specific CD8+ T cells in the context of an actively persisting infection