HCV replication in gastrointestinal mucosa: Potential extra-hepatic viral reservoir and possible role in HCV infection recurrence after liver transplantation

No association between hepatitis C virus infection and risk of colorectal cancer: a systematic review and meta-analysis of cohort studies

Background and aim

There is still uncertainty regarding whether hepatitis C virus (HCV) infection is associated with colorectal cancer (CRC). This study aims to investigate the potential association between HCV infection and CRC through a systematic review and meta-analysis of cohort studies.

Methods

PubMed, Embase, and Web of Science were systematically searched from the beginning of their inception to October 2023 to find relevant cohort studies on the association between HCV infection and CRC risk. The random-effect, generic inverse variance method was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for CRC outcome among individuals with HCV infection. We also performed subgroup and sensitivity analysis.

Results

A total of 8 cohort studies involving 1,939,164 participants were included in this meta-analysis. The result from the meta-analysis suggested that there was no statistically significant association between HCV and the risk of developing CRC (HR = 0.99, 95% CI: 0.82-1.88, p = 0.88) with low statistical heterogeneity (I2 = 28%, p = 0.20). Subgroup analyses that were conducted based on study design, diagnosis of HCV infection, and publication year yielded similar results. Analyses of subgroups based on study areas revealed that there was no significant association between HCV infection and CRC risk in Asia (n = 2, HR = 0.96, 95% CI: 0.71-1.29, p = 0.79; I2 = 26%), Europe (n = 3, HR = 1.06, 95% CI: 0.83-1.37, p = 0.63; I2 = 0%), and North America (n = 2, HR = 1.10, 95% CI: 0.87-1.38, p = 0.44; I2 = 0%); however, a negative correlation was found in Oceania (n = 1, HR = 0.43, 95% CI: 0.22-0.84, p = 0.01). Sensitivity analysis further reinforce the stability of our conclusion.

Conclusion

Our cohort-based meta-analysis showed insufficient evidence to support the association between HCV infection and an increased risk of CRC. To gain a clearer insight into the potential association between these two conditions, it would be beneficial to conduct large, well-designed, high-quality prospective cohort studies that consider different ethnic populations and potential confounding factors.Systematic review registration: PROSPERO, identifier [CRD42023472688], https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023472688.

Contemporary Insights into Hepatitis C Virus: A Comprehensive Review

Hepatitis C virus (HCV) remains a significant global health challenge. Approximately 50 million people were living with chronic hepatitis C based on the World Health Organization as of 2024, contributing extensively to global morbidity and mortality. The advent and approval of several direct-acting antiviral (DAA) regimens significantly improved HCV treatment, offering potentially high rates of cure for chronic hepatitis C. However, the promising aim of eventual HCV eradication remains challenging. Key challenges include the variability in DAA access across different regions, slightly variable response rates to DAAs across diverse patient populations and HCV genotypes/subtypes, and the emergence of resistance-associated substitutions (RASs), potentially conferring resistance to DAAs. Therefore, periodic reassessment of current HCV knowledge is needed. An up-to-date review on HCV is also necessitated based on the observed shifts in HCV epidemiological trends, continuous development and approval of therapeutic strategies, and changes in public health policies. Thus, the current comprehensive review aimed to integrate the latest knowledge on the epidemiology, pathophysiology, diagnostic approaches, treatment options and preventive strategies for HCV, with a particular focus on the current challenges associated with RASs and ongoing efforts in vaccine development. This review sought to provide healthcare professionals, researchers, and policymakers with the necessary insights to address the HCV burden more effectively. We aimed to highlight the progress made in managing and preventing HCV infection and to highlight the persistent barriers challenging the prevention of HCV infection. The overarching goal was to align with global health objectives towards reducing the burden of chronic hepatitis, aiming for its eventual elimination as a public health threat by 2030.

Molecular Analysis and Ex Vivo Infectivity of Seronegative Occult Hepatitis C Virus: A Study in Single Haemodialysis Centre

Background

In occult hepatitis C virus infection (OCI), hepatitis C virus ribonucleic acid (HCV RNA) is detectable in peripheral blood mononuclear cells (PBMCs) but is not evident in serum or plasma. Understanding of OCI in patients with seronegative anti-HCV antibodies is limited.

Methods

In this study, six HCV isolates from haemodialysis (HD) patients with seronegative OCI were identified by molecular assays and phylogenetic analysis. The virus infectivity was assessed ex vivo using a primary naïve PBMC culture system. HCV isolates obtained from the PBMCs of 10 patients with chronic HCV infection (CCI) were characterised concurrently and used as positive controls in the cell culture.

Results

Sequence analysis of the 5' untranslated region (UTR) and non-structural 5B (NS5B) region revealed that HCV genotype 3 was the most prevalent virus type in both the OCI and CCI groups. One of the occult HCV isolates was identified as a mixed type. The mean viral load (log10 RNA copies/106 cells) in the PBMC samples of the OCI group (M = 3.4, SD = 0.7) was lower than that of the CCI group (M = 4.6, SD = 1.7). Upon culture, de novo OCI-HCV replicates were detected in five out of six naïve PBMC cultures. Analysis of the replicates showed a single guanine addition in the domain III of 5'-UTR but the overall molecular structure was retained.

Conclusion

Seronegative OCI is an active form of infection that replicates at a low level in PBMCs. Seronegative OCI may share the same route of transmission as CCI. The retained viral competency may have an implication for its persistence.

Assessing Tissue Transmission of Hepatitis C Virus From Viremic Donor to Seronegative Kidney Transplant Recipients: A Case Series

The transmission of hepatitis C virus from viremic donors to seronegative recipients of kidney transplantation is well documented. Pre-transplant administration of direct-acting antivirals prevents viremia, but the seroconversion rate is high. We studied the transmission of the virus through the transplanted tissue by determining viral RNA in 15 kidneys from 8 deceased viremic donors, 5 males and 3 females aged 52.3 ± 15 years. HIV positive donors and active intravenous drugs abusers were discarded to avoid possible window periods in the virus transmission. Recipients, 9 males and 6 females aged 52.7 ± 18 years, were treated with glecaprevir/pibrentasvir for 8 weeks and received immunosuppression with thymoglobulin, tacrolimus, sirolimus and prednisone. Hepatitis C Virus was detected in 9 of the 15 histological samples analyzed but viremia was detected in no recipient at day 1 and 7 post-transplantation and 12 weeks after the treatment. However, 13 of the 15 recipients had seroconverted within 1 month. In conclusion, Hepatitis C virus was detected in a significant proportion of tissue of kidney grafts from viremic donors, but treatment with direct-acting antivirals avoids the transmission of the virus from donor to recipient. Then Donor pools should be expanded.

Galectin-9 and Interferon-Gamma Are Released by Natural Killer Cells upon Activation with Interferon-Alpha and Orchestrate the Suppression of Hepatitis C Virus Infection

Natural killer (NK) cells mount an immune response against hepatitis C virus (HCV) infection and can be activated by several cytokines, including interleukin-2 (IL-2), IL-15, and interferon-alpha (IFN-α). By exploiting the Huh7.5 hepatoma cell line infected with the HCV JFH1 genome, we provide novel insights into the antiviral effector functions of human primary NK cells after cytokine stimulation. NK cells activated with IFN-α (IFNα-NKs) had enhanced contact-dependent and -independent responses as compared with NK cells activated with IL-2/IL-15 (IL2/IL15-NKs) and could inhibit HCV replication both in vitro and in vivo. Importantly, IFN-α, but not IL-2/IL-15, protected NK cells from the functional inhibition exerted by HCV. By performing flow cytometry, multiplex cytokine profiling, and mass-spectrometry-based proteomics, we discovered that IFNα-NKs secreted high levels of galectin-9 and interferon-gamma (IFN-γ), and by conducting neutralization assays, we confirmed the major role of these molecules in HCV suppression. We speculated that galectin-9 might act extracellularly to inhibit HCV binding to host cells and downstream infection. In silico approaches predicted the binding of HCV envelope protein E2 to galectin-9 carbohydrate-recognition domains, and co-immunoprecipitation assays confirmed physical interaction. IFN-γ, on the other hand, triggered the intracellular expressions of two antiviral gate-keepers in target cells, namely, myxovirus-1 (MX1) and interferon-induced protein with tetratricopeptide repeats 1 (IFIT1). Collectively, our data add more complexity to the antiviral innate response mediated by NK cells and highlight galectin-9 as a key molecule that might be exploited to neutralize productive viral infection.

HCV Interplay With Mir34a: Implications in Hepatocellular Carcinoma

Since its identification, HCV has been considered one of the main causes of hepatitis and liver cancer. Currently, the molecular mechanisms of HCC development induced by HCV infection have not been sufficiently clarified. The recent discovery of novel treatments that inhibit HCV replication gave rise to new questions concerning HCC mechanisms. In particular, the HCV eradication mediated by new direct-acting antiviral (DAAs) drugs does not exclude the possibility of de novo HCC development; this finding opened more questions on the interplay between liver cells and the virus. Different groups have investigated the pathways leading to cancer recurrence in patients treated with DAAs. For this reason, we tried to gain molecular insights into the changes induced by HCV infection in the target liver cells. In particular, we observed an increase in microRNA34a (miR34a) expression following HCV infection of HCC cell line Huh7.5. In addition, Huh7.5 treated with extracellular vesicles (EVs) from the previously HCV-infected Huh7.5 underwent apoptosis. Since miR34 expression was increased in Huh7.5 EVs, we hypothesized a paracrine mechanism of viral infection mediated by miR34a cargo of EVs. The balance between viral infection and cell transformation may raise some questions on the possible use of antiviral drugs in association with antineoplastic treatment.

Occult Infection with Hepatitis C Virus: Looking for Clear-Cut Boundaries and Methodological Consensus

The sustained virologic response and elimination of HCV is widely viewed as a true cure of chronic hepatitis C as it associates with amelioration of histological liver damage and improved clinical outcomes. Therefore, the existence and clinical burden of occult HCV infection (OCI) has been a controversial issue for many years. In this review, we summarize recently published data that adds new information on the molecular and clinical background of OCI and its epidemiological significance. We also identify and discuss the most important methodological pitfalls, which can be a source of inconsistency between studies. Data that have accumulated so far, strongly support the existence of extrahepatic HCV replication in individuals negative for serum HCV-RNA by conventional clinical tests. OCI emerges as a condition where the immune system is unable to fully resolve infection but it is continuously stimulated by low levels of HCV antigens, leading to progression of liver pathology and extrahepatic HCV-related complications. Moreover, the development of monitoring strategies or management guidelines for OCI is still hampered by the lack of clear definition and the confusion regarding its clinical significance. Careful study design and the introduction of uniform protocols for the detection of low-level HCV-RNA are crucial for obtaining reliable data on OCI.

Chronic Viral Hepatitis Is Associated with Colorectal Neoplasia: A Systematic Review and Meta-Analysis

BACKGROUND

Chronic viral hepatitis is associated with a wide range of extrahepatic diseases; however, evidence on a link between chronic viral hepatitis and colorectal neoplasia is still lacking.

AIMS

To analyze the association between chronic viral hepatitis and prevalence of colorectal neoplasia.

METHODS

A systematic review of articles published in the MEDLINE, EMBASE, and Cochrane Library between 2000 and 2020 was performed. Subgroup analyses based on the types of colorectal neoplasia and the etiology of chronic viral hepatitis were conducted.

RESULTS

Twelve eligible studies with 48,428 hepatitis B virus (HBV) patients and 46,561 hepatitis C virus (HCV) patients were included. Chronic viral hepatitis was significantly associated with an increased risk of both colorectal adenoma (odds ratio [OR], 1.53; 95% confidence interval [CI], 1.16-2.02; I² = 83%) and colorectal cancer (CRC) (OR, 1.32; 95% CI, 1.08-1.61; I² = 94%). The etiology of chronic viral hepatitis was an independent factor related to heterogeneity for CRC subgroup analysis revealed an increased risk of CRC in both HBV (OR, 1.18; 95% CI, 1.09-1.27; I² = 37%) and HCV (OR, 1.88; 95% CI, 1.78-1.97; I² = 0%). HCV was associated with an increased risk of colorectal adenoma (OR, 1.48; 95% CI, 1.22-1.79; I² = 0%); however, HBV was not associated with an increased risk of colorectal adenoma and had considerable heterogeneity (OR, 1.65; 95% CI, 0.88-3.09; I² = 90%).

CONCLUSION

Our meta-analysis showed that chronic viral hepatitis is associated with an increased risk of colorectal neoplasia. The strategy of stricter screening colonoscopy may benefit from patients with chronic viral hepatitis.

Late Relapse and Reinfection in HCV Patients Treated with Direct-Acting Antiviral (DAA) Drugs

The risk of hepatitis C virus (HCV) recurrence after direct-acting antiviral (DAA) treatment is <0.5%. However, the distinction between HCV RNA late relapse and reinfection still represents a challenge in virological diagnostics. The aim of this study was to employ next-generation sequencing (NGS) to investigate HCV RNA recurrence in patients achieving a sustained virologic response (SVR) at least six months post-treatment. NGS was performed on plasma samples from six HCV-positive patients (Pt1–6) treated with DAA. NGS of HCV NS5B was analyzed before treatment (T0), after HCV RNA rebound (T1), and, for Pt3, after a second rebound (T2). Reinfection was confirmed for Pt5, and for the first rebound observed in Pt3. Conversely, viral relapse was observed when comparing T0 and T1 for Pt6 and T1 and T2 for Pt3. Z-scores were calculated and used to predict whether HCV-positive patient samples at different time points belonged to the same quasispecies population. A low Z-score of <2.58 confirmed that viral quasispecies detected at T0 and T1 were closely related for both Pt1 and Pt2, while the Z-score for Pt4 was suggestive of possible reinfection. NGS data analyses indicate that the Z-score may be a useful parameter for distinguishing late relapse from reinfection.

Direct-acting antivirals ability to clear intestinal HCV-RNA in liver transplant patients

The hepatitis C virus mainly infects the liver but is also able to infect and replicate in other body compartments by creating an extra-hepatic reservoir that may influence the persistence of the infection after transplantation. It is unknown whether antiviral drugs affect the viral extra-hepatic sites. We evaluated the ability of pegylated/interferon + ribavirin and sofosbuvir + ribavirin to clear the virus from the gastrointestinal mucosa of liver-transplanted patients with HCV recurrence after transplantation. A total of 51 liver-transplanted patients, 30 treated with pegylated/interferon + ribavirin (ERA1) and 21 treated with sofosbuvir + ribavirin (ERA2), were enrolled, and blood serum and gastrointestinal tissues analyzed for the presence of HCV-RNA. In the ERA1 group, the 46.6% of patients had a sustained viral response to antiviral treatment, and gastrointestinal biopsies were positive for HCV in 73.3% of cases, 54.5% of responders, and 45.5% of non-responders. In the ERA2 group, the 66.6% had a sustained viral response, and gastrointestinal HCV-RNA was present in the 14.3% of patients, all relapsers. Sofosbuvir + ribavirin cleared the intestinal HCV in 85.7% of patients with recurrent HCV infection, while pegylated/interferon + ribavirin cleared it in 26.6% of treated patients, demonstrating the better effectiveness of new direct antiviral agents in clearing HCV intestinal reservoir.

Viral miRNAs as Active Players and Participants in Tumorigenesis

The theory that viruses play a role in human cancers is now supported by scientific evidence. In fact, around 12% of human cancers, a leading cause of morbidity and mortality in some regions, are attributed to viral infections. However, the molecular mechanism remains complex to decipher. In recent decades, the uncovering of cellular miRNAs, with their invaluable potential as diagnostic and prognostic biomarkers, has increased the number of studies being conducted regarding human cancer diagnosis. Viruses develop clever mechanisms to succeed in the maintenance of the viral life cycle, and some viruses, especially herpesviruses, encode for miRNA, v-miRNAs. Through this viral miRNA, the viruses are able to manipulate cellular and viral gene expression, driving carcinogenesis and escaping the host innate or adaptive immune system. In this review, we have discussed the main viral miRNAs and virally influenced cellular pathways, and their capability to drive carcinogenesis.

Sustained virological response at week 12 after interferon-free therapy as criterion for HCV cure definition: Validation in a real-life cohort of HIV-coinfected patients

INTRODUCTION

Sustained virological response (SVR) 12 weeks after the end-of-therapy (EOT) has been correlated with SVR24 for HCV-monoinfection. We aim to validate SVR12 as criterion for definition of HCV cure in HIV-coinfected patients treated with all-oral direct-acting antivirals (DAA).

METHODS

Prospectively observational study including HIV/HCV-coinfected subjects who received DAA and had HCV-RNA measures at weeks 12 and 24 after EOT. Every patient who took ≥1 drug dose was analyzed.

RESULTS

DAA were prescribed to 423 patients, of whom 387 had HCV-RNA measures both at weeks 12 and 24 after EOT. SVR12 was confirmed in 379/387 patients, while SVR24 was confirmed in 377/387 subjects. The positive-predictive-value (PPV) of SVR12 for SVR24 was 99.5% (95%CI: 98.1-99.9). One of the recurrences was clinically suspected to be a late relapse.

CONCLUSIONS

SVR12 has a high PPV for HCV cure in HIV/HCV-coinfection, though further follow-up could be necessary for those with deeper immunosuppression.

Bioinformatics Analysis of Quantitative PCR and Reverse Transcription PCR in Detecting HCV RNA

Objective:

This research aimed to make comparisons of sensitivity and specificity between Quantitative real Time Polymerase Chain Reaction (Q-PCR) and Reverse Transcription PCR (RT-PCR) in detecting the ribonucleic acid (RNA) expression levels of Hepatitis C Virus (HCV).

Methods:

121 patients suffering from hepatitis C and 98 healthy participants with normal liver functions were identified. The venous blood collections were carried out, were subjected to detect the expression levels of HCV RNA via Q-PCR and RT-PCR. And then, the data obtained from these above two detection methods were compared, including the sensitivity and specificity.

Results:

In terms of Q-PCR, the positive rate of HCV RNA was 72.16%, which was significantly higher when compared with 55.26% of RT-PCR. After statistical analysis, the difference between them was statistically significant (P＜0.05). Among the healthy participants, 4 cases were false positive by means of RT-PCR, there was the possibility of missed diagnosis when the samples were evaluated by Q-PCR.

Conclusion:

: The Q-PCR detection technology performed well in testing HCV, with pretty high sensitivity and specificity. Nevertheless, the false negative results obtained from Q-PCR could not be avoided. In clinical practice, these above two detection methods should be referred to, in order to avoid missed diagnosis.

Hepatitis C Virus Infection and Cholangiocarcinoma: An Insight into Epidemiologic Evidences and Hypothetical Mechanisms of Oncogenesis

Hepatitis C virus (HCV) infection is a global public health problem because it is a main cause of liver cirrhosis and hepatocellular carcinoma. This human oncogenic virus is also associated with the development of non-Hodgkin lymphoma and cholangiocarcinoma (CCA). The association between HCV infection and CCA has been examined in a number of epidemiologic studies. However, in vivo and in vitro results demonstrating the oncogenic mechanisms of HCV in CCA development and progression are insufficient. Here, we review the epidemiologic association of HCV and CCA and recent publications of studies of HCV infection of cholangiocytes and CCA cell lines as well as studies of viral infection performed with liver samples obtained from patients. In addition, we also discuss the preliminary results of in vitro assays of HCV protein expression in CCA cell lines. Finally, we discuss the hypothetical role of HCV infection in CCA development by induction of epithelial-mesenchymal transition and up-regulation of hedgehog signaling, and consequently biliary tree inflammation and liver fibrosis. Further studies are required to demonstrate these hypotheses and therefore to elucidate the mechanisms of HCV as a risk factor for CCA.

Very late relapse of hepatitis C virus infection immediately after liver transplant

Late relapse of hepatitis C virus (HCV) infection is very rare in the era of modern direct-acting antiviral therapy. We report here the first case of a late relapse, after direct-acting antiviral therapy, occurring immediately after liver transplant (LT), with 93 weeks of sustained virologic response before LT. HCV RNA in serum and in liver biopsy was negative the day of LT, and relapse was diagnosed 11 days after LT. HCV NS5A sequencing was performed on samples before and after LT, with 99% of homology demonstrating a true late relapse rather than a reinfection. This late relapse could be explained by extrahepatic reservoirs of HCV and the high immunosuppressive therapy, including bolus of steroids, within the first days post LT. In conclusion, our case suggests that monitoring HCV RNA after LT could be recommended to detect and treat early relapse, even after a long virologic response.

Hepatitis B Virus Adaptation to the CD8+ T Cell Response: Consequences for Host and Pathogen

Chronic viral hepatitis infections are a major public health concern, with an estimated 290 million individuals infected with hepatitis B virus (HBV) globally. This virus has been a passenger in human populations for >30,000 years, and remains highly prevalent in some settings. In order for this endemic pathogen to persist, viral adaptation to host immune responses is pre-requisite. Here, we focus on the interplay between HBV infection and the CD8+ T cell response. We present the evidence that CD8+ T cells play an important role in control of chronic HBV infection and that the selective pressure imposed on HBV through evasion of these immune responses can potentially influence viral diversity, chronicity, and the outcome of infection, and highlight where there are gaps in current knowledge. Understanding the nature and mechanisms of HBV evolution and persistence could shed light on differential disease outcomes, including cirrhosis and hepatocellular carcinoma, and help reach the goal of global HBV elimination by guiding the design of new strategies, including vaccines and therapeutics.

Time course of cellular HIV-DNA and low-level HIV viremia in HIV-HCV co-infected patients whose HCV infection had been successfully treated with directly acting antivirals

This longitudinal study described cellular HIV-DNA changes and their correlation with HIV low-level plasma viremia (LLV) in HIV-HCV co-infected patients on successful antiretroviral and anti-HCV therapy by treatment with direct-acting antivirals (DAA). Thirty-nine patients were examined prior to the start of DAA (T0), after week 12 (T1) and 24 weeks (T2) of anti-HCV therapy. Cellular PBMC HIV-DNA was analysed as an absolute value and as the percentage of increase or decrease from T0 to T2. Patients were classified as having undetectable plasma HIV viraemia (UV) or LLV in the year before the start of anti-HCV treatment and within the T0-T2 study period. Thirty-five patients (89.7%) of the 39 subjects enrolled had the same plasma HIV viraemia control in the year before HCV treatment and in the T0-T2 interval. The HIV-DNA value at T0 and at T2 was higher in patients with LLV than in subjects with UV (p = 0.015 and p = 0.014, respectively). A similar proportion of patients with LLV and UV experienced an increase or decrease of HIV-DNA from T0 to T2. The percentage increase in HIV-DNA value (262.8%) from T0 to T2 was higher compared to the decrease (43.5%) in patients with UV (p = 0.012), and it was higher compared to the percentage increase in HIV-DNA value reported in subjects with LLV (262.8 versus 49%, p = 0.026). HIV-HCV co-infected patients experienced a multifaceted perturbation of cellular HIV-DNA levels within a 24-week period during anti-HCV treatment; the extent of the phenomenon was greater in subjects with UV. Fast HCV-RNA clearance seemed to have a greater influence on the cellular reservoir than on plasma HIV-RNA.