Long-lasting Imprint in the Soluble Inflammatory Milieu despite Early Treatment of Acute Symptomatic Hepatitis C

Hepatitis C Virus and the Host: A Mutual Endurance Leaving Indelible Scars in the Host's Immunity

Hepatitis C virus (HCV) has spread worldwide, and it is responsible for potentially severe chronic liver disease and primary liver cancer. Chronic infection remains for life if not spontaneously eliminated and viral persistence profoundly impairs the efficiency of the host's immunity. Attempts have been made to develop an effective vaccine, but efficacy trials have met with failure. The availability of highly efficacious direct-acting antivirals (DAA) has created hope for the progressive elimination of chronic HCV infections; however, this approach requires a monumental global effort. HCV elicits a prompt innate immune response in the host, characterized by a robust production of interferon-α (IFN-α), although interference in IFN-α signaling by HCV proteins may curb this effect. The late appearance of largely ineffective neutralizing antibodies and the progressive exhaustion of T cells, particularly CD8 T cells, result in the inability to eradicate the virus in most infected patients. Moreover, an HCV cure resulting from DAA treatment does not completely restore the normal immunologic homeostasis. Here, we discuss the main immunological features of immune responses to HCV and the epigenetic scars that chronic viral persistence leaves behind.

Immunological and senescence biomarker profiles in patients after spontaneous clearance of hepatitis C virus: gender implications for long-term health risk

BACKGROUND

About 25% of patients with acute hepatitis C virus (HCV) infection show spontaneous clearance within the first six months of infection but may remain at risk of inflammaging, aging, and liver and non-liver disease complications. This study evaluated the differences in the plasma levels of immune checkpoints (ICs) and senescence-associated secretory phenotype (SASP) biomarkers between patients who had spontaneously eliminated HCV infection (SC group) and individuals without evidence of HCV infection (C group).

METHODS

We performed a multicenter retrospective study of 56 individuals: 32 in the SC and 24 in the C groups. ICs and SASP proteins were analyzed using a Luminex 200TM analyzer. The statistical analysis used Generalized Linear Models with gamma distribution (log-link) adjusted by significant variables and sex.

RESULTS

13 ICs (BTLA, CD137(4-1BB), CD27, CD28, CD80, GITR, HVEM, IDO, LAG-3, PD-1, PD-L1, PD-L2, and TIM-3) and 13 SASP proteins (EGF, Eotaxin, IL-1alpha, IL-1RA, IL-8, IL-13, IL-18, IP-10, SDF-1alpha, HGF, beta-NGF, PLGF-1, and SCF) were significantly higher in SC group after approximately more than two years of HCV clearance. After stratifying by sex, differences remained significant for males, which showed higher levels for 13 ICs and 4 SASP proteins in SC. While only PD-L2 was significantly higher in SC women, and no differences in SASP were found.

CONCLUSIONS

Higher plasma levels of different IC and SASP proteins were found in individuals after more than two years of HCV clearance, mainly in men. Alterations in these molecules might be associated with an increased risk of developing liver and non-hepatic diseases.

Proteomics reveals a global phenotypic shift of NK cells in HCV patients treated with direct-acting antivirals

Chronic hepatitis C virus (HCV) infections compromise natural killer (NK)-cell immunity. Direct-acting antivirals (DAA) effectively eliminate HCV, but the long-term effects on NK cells in cured patients are debated. We conducted a proteomic study on CD56+ NK cells of chronic HCV-infected patients before and 1 year after DAA therapy. Donor-variation was observed in NK-cell proteomes of HCV-infected patients, with 46 dysregulated proteins restored after DAA therapy. However, 30% of the CD56+ NK-cell proteome remained altered 1 year post-therapy, indicating a phenotypic shift with low donor-variation. NK cells from virus-negative cured patients exhibited global regulation of RNA-processing and pathways related to "stimuli response", "chemokine signaling", and "cytotoxicity regulation". Proteomics identified downregulation of vesicle transport components (CD107a, COPI/II complexes) and altered receptor expression profiles, indicating an inhibited NK-cell phenotype. Yet, activated NK cells from HCV patients before and after therapy effectively upregulated IFN-γ and recruited CD107a. Conversely, reduced surface expression levels of Tim-3 and 2B4 were observed before and after therapy. In conclusion, this study reveals long-term effects on the CD56+ NK-cell compartment in convalescent HCV patients 1 year after therapy, with limited abundance of vesicle transport complexes and surface receptors, associated with a responsive NK-cell phenotype.

Controlled Attenuation Parameter Is Associated with a Distinct Systemic Inflammatory Milieu after Clearance of HCV Infection

Hepatitis C virus (HCV) infection is closely associated with lipid metabolism defects along with a high prevalence of hepatic steatosis. After HCV clearance, steatosis persists in many patients. However, the reasons behind this phenomenon are not completely clear. To investigate the association between 92 soluble inflammatory mediators (SIMs) and the steatosis grade, we made use of a cohort of 94 patients with chronic HCV infection who cleared HCV after direct-acting antiviral agent (DAA) treatment. Patients were classified into three groups according to their controlled attenuation parameter (CAP). CAP is associated with ALT, γ-GT and liver stiffness after HCV clearance. While stem cell factor (SCF) and tumor necrosis factor ligand superfamily member 12 (TWEAK) levels were significantly reduced in patients with CAP > 299 dB/m, the levels of fibroblast growth factor (FGF)-21 and interleukin-18 receptor 1 (IL-18R1) were higher in those patients at week 96 after virus clearance. These four markers also showed a linear correlation with CAP values. FGF-21 levels correlated with CAP only after HCV clearance. Taken together, these four biomarkers, namely SCF, TWEAK, FGF-21 and IL-18R1, are associated with CAP status after virus clearance. A potential role of these proteins in the pathogenesis of post-sustained viral response (SVR) nonalcoholic steatohepatitis requires further investigation.

Detection of Novel Biomarkers in Pediatric Autoimmune Hepatitis by Proteomic Profiling

Autoimmune hepatitis (AIH) is characterized by immune-mediated hepatocyte injury resulting in the destruction of liver cells, causing inflammation, liver failure, and fibrosis. Pediatric (AIH) is an autoimmune inflammatory disease that usually requires immunosuppression for an extended period. Frequent relapses after treatment discontinuation demonstrate that current therapies do not control intrahepatic immune processes. This study describes targeted proteomic profiling data in patients with AIH and controls. A total of 92 inflammatory and 92 cardiometabolic plasma markers were assessed for (i) pediatric AIH versus controls, (ii) AIH type 1 versus type 2, (iii) AIH and AIH-autoimmune sclerosing cholangitis overlapping syndrome and (iv) correlations with circulating vitamin D levels in AIH. A total of 16 proteins showed a nominally significant differential abundance in pediatric patients with AIH compared to controls. No clustering of AIH subphenotypes based on all protein data was observed, and no significant correlation of vitamin D levels was observed for the identified proteins. The proteins that showed variable expression include CA1, CA3, GAS6, FCGR2A, 4E-BP1 and CCL19, which may serve as potential biomarkers for patients with AIH. CX3CL1, CXCL10, CCL23, CSF1 and CCL19 showed homology to one another and may be coexpressed in AIH. CXCL10 seems to be the central intermediary link for the listed proteins. These proteins were involved in relevant mechanistic pathways for liver diseases and immune processes in AIH pathogenesis. This is the first report on the proteomic profile of pediatric AIH. The identified markers could potentially lead to new diagnostic and therapeutic tools. Nevertheless, considering the complex pathogenesis of AIH, more extensive studies are warranted to replicate and validate the present study's findings.

Immunological scars after cure of hepatitis C virus infection: Long-HepC?

Hepatitis C virus (HCV) infection provides a unique opportunity to study the effects of spontaneous or treatment-induced viral elimination on the human immune system. Twenty to 50% of patients with acute HCV infection spontaneously clear the virus, which is related to the quality of the individual's immune response, while the chronic infection is associated with an altered and impaired immune response. Direct-acting antiviral agents are now available that provide sustained viral elimination in more than 95% of patients with chronic HCV infection. Viral elimination leads to a decrease in disease sequelae such as cirrhosis and hepatocellular carcinoma, and extrahepatic manifestations also improve. However, some patients may still experience long-term complications, and viral elimination does not protect against HCV reinfection. This review addresses the question of whether the altered and impaired immune response caused by HCV normalizes after viral elimination and if this may affect the long-term clinical course after HCV cure.

Early initiation of glecaprevir/pibrentasvir after transplantation of HCV-viremic kidneys into HCV-negative recipients is associated with normalization in the altered inflammatory milieu

Our previous Multicenter Trial to Transplant HCV-infected Kidneys (MYTHIC) observed that 100% of hepatitis C virus (HCV)-uninfected patients who received a kidney from an HCV-infected deceased donor were cured of HCV with an 8-week regimen of glecaprevir and pibrentasvir (G/P) initiated 2-5 days after transplantation. Following acute and chronic infection with HCV, immune system perturbations have been reported to persist even after viral clearance. The aim of this study was to determine whether HCV viremic kidney recipients in the MYTHIC study experience sustained changes in the soluble inflammatory milieu associated with HCV infection. Among nine patients with HCV viremia at day 3 post-kidney transplant (post-KT D3), IP-10, IL-10, MIP-1β, and IL-8 were significantly elevated from baseline. However, over the subsequent visits, there was a rapid, dramatic reduction back to baseline levels. Among seven patients who were not HCV viremic at post-KT D3, the cytokine levels did not significantly change. HCV-uninfected patients who received a kidney from an HCV-viremic deceased donor and were treated with early G/P experienced only transient alterations in the soluble inflammatory milieu. These data provide reassuring evidence that there appear to be no persistent cytokine disturbances with transient HCV viremia accompanying HCV donor positive/recipient negative kidney transplant.

Enhanced TLR3 responsiveness in hepatitis C virus resistant women from the Irish anti-D cohort

Natural resistance to infection is an overlooked outcome after hepatitis C virus (HCV) exposure. Between 1977 and 1979, 1,200 Rhesus D-negative Irish women were exposed to HCV-contaminated anti-D immunoglobulin. Here, we investigate why some individuals appear to resist infection despite exposure (exposed seronegative [ESN]). We screen HCV-resistant and -susceptible donors for anti-HCV adaptive immune responses using ELISpots and VirScan to profile antibodies against all know human viruses. We perform standardized ex vivo whole blood stimulation (TruCulture) assays with antiviral ligands and assess antiviral responses using NanoString transcriptomics and Luminex proteomics. We describe an enhanced TLR3-type I interferon response in ESNs compared with seropositive women. We also identify increased inflammatory cytokine production in response to polyIC in ESNs compared with seropositive women. These enhanced responses may have contributed to innate immune protection against HCV infection in our cohort.

The Transmission Route and Selection Pressure in HCV Subtype 3a and 3b Chinese Infections: Evolutionary Kinetics and Selective Force Analysis

Hepatitis C virus (HCV) genotype 3 (GT-3) represents 22–30% of all infections and is the second most common genotype among all HCV genotypes. It has two main subtypes, GT-3a and GT-3b, that present epidemiological differences in transmission groups. This report generated 56 GT-3a and 64 GT-3b whole-genome sequences to conduct an evolutionary kinetics and selective force analysis with reference sequences from various countries. Evolutionary analysis showed that HCV GT-3a worldwide might have been transmitted from the Indian subcontinent to South Asia, Europe, North America and then become endemic in China. In China, GT-3a may have been transmitted by intravenous drug users (IDUs) and become endemic in the general population, while GT-3b may have originated from IDUs and then underwent mutual transmission between blood donors (BDs) and IDUs, ultimately becoming independently endemic in IDUs. Furthermore, the spread of GT-3a and GT-3b sequences from BD and IDU populations exhibit different selective pressures: the proportion of positively selected sites (PPSs) in E1 and E2 from IDUs was higher than in BDs. The number of positive selection sites was higher in GT-3b and IDUs. These results indicate that different selective constraints act along with the GT-3a and GT-3b genomes from IDUs and BDs. In addition, GT-3a and GT-3b have different transmission routes in China, which allows us to formulate specific HCV prevention and control strategies in China.

Implementation of a controlled human infection model for evaluation of HCV vaccine candidates

Hepatitis C virus (HCV) remains a major global health concern. Directly acting antiviral (DAA) drugs have transformed the treatment of HCV. However, it has become clear that, without an effective HCV vaccine, it will not be possible to meet the World Health Organization targets of HCV viral elimination. Promising new vaccine technologies that generate high magnitude antiviral T and B cell immune responses and significant new funding have recently become available, stimulating the HCV vaccine pipeline. In the absence of an immune competent animal model for HCV, the major block in evaluating new HCV vaccine candidates will be the assessment of vaccine efficacy in humans. The development of a controlled human infection model (CHIM) for HCV could overcome this block, enabling the head-to-head assessment of vaccine candidates. The availability of highly effective DAA means that a CHIM for HCV is possible for the first time. In this review, we highlight the challenges and issues with currently available strategies to assess HCV vaccine efficacy including HCV "at-risk" cohorts and animal models. We describe the development of CHIM in other infections that are increasingly utilized by trialists and explore the ethical and safety concerns specific for an HCV CHIM. Finally, we propose an HCV CHIM study design including the selection of volunteers, the development of an infectious inoculum, the evaluation of host immune and viral parameters, and the definition of study end points for use in an HCV CHIM. Importantly, the study design (including number of volunteers required, cost, duration of study, and risk to volunteers) varies significantly depending on the proposed mechanism of action (sterilizing/rapid viral clearance vs. delayed viral clearance) of the vaccine under evaluation. We conclude that an HCV CHIM is now realistic, that safety and ethical concerns can be addressed with the right study design, and that, without an HCV CHIM, it is difficult to envisage how the development of an HCV vaccine will be possible.

Soluble inflammatory mediators identify HCV patients who may be cured with four weeks of antiviral treatment

Soluble inflammatory mediators (SIM) can be predictive of treatment outcome in antiviral treatment of chronic hepatitis C. Recently, it was shown that a subgroup of patients can be cured with four weeks of therapy. We here profiled patients for 70 SIM before and during treatment of hepatitis C with glecaprevir/pibrentasvir (GLE/PIB) +/- ribavirin. Proximity extension assay was performed in a total of 32 patients. Pre-treatment SIM profiles did not distinguish patients achieving an SVR (n = 21) from patients experiencing antiviral relapse (n = 11). However, after 4 weeks of therapy, eight markers were identified that could distinguish patients with SVR from the relapsed group, namely MMP-10, CCL20, CXCL11, FGF-23, TNF, MCP-2, IL-18R1 and CXCL10. Thus, this study shows that a distinct on-treatment immune profile is associated with cure of HCV infection after ultrashort treatment.

Uncovering Resistance to Hepatitis C Virus Infection: Scientific Contributions and Unanswered Questions in the Irish Anti-D Cohort

Infections caused inadvertently during clinical intervention provide valuable insight into the spectrum of human responses to viruses. Delivery of hepatitis C virus (HCV)-contaminated blood products in the 70s (before HCV was identified) have dramatically increased our understanding of the natural history of HCV infection and the role that host immunity plays in the outcome to viral infection. In Ireland, HCV-contaminated anti-D immunoglobulin (Ig) preparations were administered to approximately 1700 pregnant Irish rhesus-negative women in 1977–1979. Though tragic in nature, this outbreak (alongside a smaller episode in 1993) has provided unique insight into the host factors that influence outcomes after HCV exposure and the subsequent development of disease in an otherwise healthy female population. Despite exposure to highly infectious batches of anti-D, almost 600 of the HCV-exposed women have never shown any evidence of infection (remaining negative for both viral RNA and anti-HCV antibodies). Detailed analysis of these individuals may shed light on innate immune pathways that effectively block HCV infection and potentially inform us more generally about the mechanisms that contribute to viral resistance in human populations.

OUP accepted manuscript

Even 30 years after the discovery of the hepatitis C virus (HCV) in humans there is still no vaccine available. Reasons for this include the high mutation rate of HCV, which allows the virus to escape immune recognition and the absence of an immunocompetent animal model for vaccine development. Phylogenetically distinct hepaciviruses (genus Hepacivirus, family Flaviviridae) have been isolated from diverse species, each with a narrow host range: the equine hepacivirus (EqHV) is the closest known relative of HCV. In this study, we used amplicon-based deep-sequencing to investigate the viral intra-host population composition of the genomic regions encoding the surface glycoproteins E1 and E2. Patterns of E1E2 substitutional evolution were compared in longitudinally sampled EqHV-positive sera of naturally and experimentally infected horses and HCV-positive patients. Intra-host virus diversity was higher in chronically than in acutely infected horses, a pattern which was similar in the HCV-infected patients. However, overall glycoprotein variability was higher in HCV compared to EqHV. Additionally, selection pressure in HCV populations was higher, especially within the N-terminal region of E2, corresponding to the hypervariable region 1 (HVR1) in HCV. An alignment of glycoprotein sequences from diverse hepaciviruses identified the HVR1 as a unique characteristic of HCV: hepaciviruses from non-human species lack this region. Together, these data indicate that EqHV infection of horses could represent a powerful surrogate animal model to gain insights into hepaciviral evolution and HCVs HVR1-mediated immune evasion strategy.

Imprint of unconventional T-cell response in acute hepatitis C persists despite successful early antiviral treatment

Unconventional T cells (UTCs) are a heterogeneous group of T cells that typically exhibit rapid responses toward specific antigens from pathogens. Chronic hepatitis C virus (HCV) infection causes dysfunction of several subsets of UTCs. This altered phenotype and function of UTCs can persist over time even after direct-acting antiviral (DAA)-mediated clearance of chronic HCV. However, it is less clear if and how UTCs respond in acute, symptomatic HCV infection, a rare clinical condition, and if rapid DAA treatment of such patients reverses the caused perturbations within UTCs. Here, we comprehensively analyzed the phenotype and reinvigoration capacity of three major UTC populations, mucosal-associated invariant T (MAIT) cells, γδ T cells, and CD4 and CD8 double-negative αβ T cells (DNT cells) before, during, and after DAA-mediated clearance of acute symptomatic HCV infection. Furthermore, MAIT cell functionality was systematically studied. We observed a reduced frequency of MAIT cells. However, remaining cells presented with a near-to-normal phenotype in acute infection, which contrasted with a significant dysfunction upon stimulation that was not restored after viral clearance. Notably, DNT and γδ T cells displayed a strong activation ex-vivo in acute HCV infection, which subsequently normalized during the treatment. In addition, DNT cell activation was specifically associated with liver inflammation and inflammatory cytokines. Altogether, these data provide evidence that UTCs respond in a cell type-specific manner during symptomatic HCV infection. However, even if early treatment is initiated, long-lasting imprints within UTCs remain over time.

Beyond the Usual Suspects: Hepatitis E Virus and Its Implications in Hepatocellular Carcinoma

Hepatitis E virus infections are the leading cause of viral hepatitis in humans, contributing to an estimated 3.3 million symptomatic cases and almost 44,000 deaths annually. Recently, HEV infections have been found to result in chronic liver infection and cirrhosis in severely immunocompromised patients, suggesting the possibility of HEV-induced hepatocarcinogenesis. While HEV-associated formation of HCC has rarely been reported, the expansion of HEV's clinical spectrum and the increasing evidence of chronic HEV infections raise questions about the connection between HEV and HCC. The present review summarizes current clinical evidence of the relationship between HEV and HCC and discusses mechanisms of virus-induced HCC development with regard to HEV pathogenesis. We further elucidate why the development of HEV-induced hepatocellular carcinoma has so rarely been observed and provide an outlook on possible experimental set-ups to study the relationship between HEV and HCC formation.

Differential Expression of the Host Lipid Regulators ANGPTL-3 and ANGPTL-4 in HCV Infection and Treatment

Host lipid metabolism reprogramming is essential for hepatitis C virus (HCV) infection and progression to severe liver disease. Direct-acting antivirals (DAAs) achieve a sustained virological response (SVR) in most patients, but virus eradication does not always protect against hepatocellular carcinoma (HCC). Angiopoietin-like protein-3 (ANGPTL-3) and angiopoietin-like protein-4 (ANGPTL-4) regulate the clearance of plasma lipids by inhibiting cellular lipase activity and possess emerging roles in tumourigenesis. We used ELISA and RT-qPCR to investigate ANGPTL-3 and ANGPTL-4 expression in HCV patients with characterised fibrosis throughout the natural history of hepatitis C and in long-term HCV infection in vitro, before and after DAA treatment. ANGPTL-3 was decreased in patients with advanced fibrosis compared to other disease stages, while ANGPTL-4 was progressively increased from acute infection to cirrhosis and HCC, peaking at the advanced fibrosis stage. Only ANGPTL-3 mRNA was down-regulated during early infection in vitro, although both ANGPTLs were increased later. DAA treatment did not alter ANGPTL-3 levels in advanced fibrosis/cirrhosis and in HCV infection in vitro, in contrast to ANGPTL-4. The association between ANGPTLs and fibrosis in HCV infection was underlined by an inverse correlation between the levels of ANGPTLs and serum transforming growth factor- β (TGF-β). Collectively, we demonstrate the pivotal role of advanced fibrosis in defining the expression fate of ANGPTLs in HCV infection and after treatment and propose a role for ANGPTL-3 as a contributor to post-treatment deregulation of lipid metabolism that could predispose certain individuals to HCC development.

Long noncoding RNA UCA1 regulates HCV replication and antiviral response via miR-145-5p/SOCS7/IFN pathway

Hepatitis C virus (HCV) infection involves a variety of viral and host factors, which leads to the dysregulation of number of relevant genes including long noncoding RNAs (LncRNAs). LncRNA urothelial carcinoma-associated 1 (UCA1) has been reported to be upregulated in HCV-infected individuals. In a bid to elucidate on the contribution of UCA1 on HCV replication, we infected Huh7.5 cells with cell culture-derived HCV and found that UCA1 expression was elevated in time- and dose-dependent manners. Functionally, UCA1 knockdown by siRNA upregulated interferon (IFN) responses, thereby increasing the expression of interferon-stimulating genes (ISGs), and subsequently suppressing HCV replication. Bioinformatics analysis and experimental results indicated that, functioning as competitive endogenous RNA, UCA1 could sponge microRNA (miR)-145-5p, which targeted suppressor of cytokine signaling 7 (SOCS7) mRNA and subsequently mediated SOCS7 silencing. Moreover, SOCS7 protein exerted an inhibitory effect on IFN responses, thereby facilitating HCV replication. Taken together, at first, our findings demonstrate that UCA1 can counteract the expression of miR-145-5p, thereby upregulating the level of SOCS7, and in turn leading to the suppression of antiviral response in Huh7.5 cells.