Search Results (317)

Chronic hepatitis B and C are major causes of cirrhosis, hepatocellular carcinoma, and liver-related mortality worldwide. The genetic diversity of hepatitis B virus (HBV) and hepatitis C virus (HCV) influences disease progression, diagnosis, vaccine response, and antiviral treatment. Periods of healthcare disruption, such as the COVID-19 pandemic, reinforce the importance of molecular surveillance to monitor viral genotypes and clinically relevant mutations. This study described the distribution of HBV and HCV genotypes and mutations in Rio de Janeiro, Brazil, during the COVID-19 pandemic. A cross-sectional study included 25 patients (15 HBV and 10 HCV) recruited between 2020 and 2022. Viral nucleic acids were amplified and sequenced by Sanger methodology, and mutations were analyzed using the Geno2pheno platform. HBV genotype A predominated (67%), comprising subgenotypes A1 (40%) and A2 (27%), followed by the rare genotypes B1 (13%), F2 (13%), and G (7%). Among HCV-infected individuals, genotypes 1a (40%) and 1b (30%) predominated, followed by genotypes 4 (20%) and 2 (10%). HBV immune escape mutations (Y100C and T126S) and unusual insertions in the S and RT domains were identified. In HCV, the substitutions C316Y, C316N, and S282R were detected. These findings highlight the importance of molecular surveillance for detecting clinically relevant viral variants. Full article

Oncogenic viruses contribute to approximately 20% of human cancers globally, with their impact falling disproportionately on populations in Sub-Saharan Africa. In this region, cervical cancer, hepatocellular carcinoma, endemic Burkitt lymphoma, and Kaposi sarcoma represent major causes of cancer-related morbidity and mortality, driven by persistent infection with human papillomavirus (HPV), hepatitis B and C viruses (HBV/HCV), Epstein–Barr virus (EBV), Kaposi sarcoma-associated herpesvirus (KSHV), and human T-lymphotropic virus-1 (HTLV-1). This review synthesizes current insights into the immunological mechanisms that underpin viral carcinogenesis in Africa, emphasizing how defective viral clearance, chronic immune activation, and immune evasion arise from the convergence of region-specific co-infections, host genetic diversity, and environmental exposures. We examine the mechanistic roles of HIV-associated CD4⁺ T cell depletion, malaria-induced perturbation of antiviral T cell immunity, helminth-driven T helper 2 polarization, and tuberculosis-associated inflammatory signaling in promoting viral persistence and malignant transformation. In addition, the influence of the extensive diversity of African human leukocyte antigens (HLA) and cytokine gene polymorphisms on antiviral immune responses and cancer susceptibility was discussed. We also assessed how virus-associated tumors establish profoundly immunosuppressive microenvironments characterized by impaired antigen presentation and the dominance of immune checkpoint pathways. Finally, we examined how gaps in vaccination, screening, and diagnostic capacity intersect with immunological vulnerability across Africa, contributing to the burden of infection-associated cancers. These challenges position Africa as a critical setting for developing targeted, genotype-inclusive public health interventions and reducing global cancer disparities through advances in immunoprevention and immunotherapy. Full article

Organic anion-transporting polypeptides (OATPs) are crucial for hepatic uptake. However, the independent contribution of SLCO1B1/1B3 germline variations to hepatocellular carcinoma (HCC) susceptibility remains controversial. This study investigated SLCO1B1/1B3 polymorphisms and HCC risk in a Turkish cohort, accounting for clinical, viral, and metabolic confounders. In this retrospective case–control study (81 HCC patients, 162 healthy controls), fully adjusted multivariable logistic regression models were constructed across multiple inheritance configurations (dominant, recessive, and additive) and adjusted for age, sex, and viral status (HBV/HCV) to address demographic and etiological discrepancies. Genotyping for SLCO1B1 (c.388A>G, c.521T>C) and SLCO1B3 (c.334T>G, c.699G>A) was performed using PCR-RFLP, cross-verified via automated digital capillary electrophoresis. Exploratory univariate analysis showed the SLCO1B1 388A>G variant was more prevalent in the HCC group. However, after strict adjustments for multiplicity and controlling for background viral etiology, age (OR: 1.10) and male sex (OR: 5.82, 95% CI: 2.74–12.41) remained the primary independent predictors, whereas the statistical significance of the genetic variant completely dissolved (p = 0.673). Notably, HCC patients exhibited profound hypocholesterolemia that significantly correlated with liver dysfunction severity; a significant inverse correlation was found between Child-Pugh scores and total cholesterol (r = −0.286, p = 0.031), validating that metabolic decline is a consequence of hepatic synthetic failure rather than an independent risk factor. Ultimately, age, male sex, and background etiological factors are the primary independent determinants characterizing HCC in this cohort, confirming that common germline SLCO variations do not exert a robust independent influence once major demographic and clinical confounders are considered. Full article

Background/Objectives: Arterial hypertension (AH) and hepatitis C virus (HCV) infection are interlinked, with AH increasing the risk of severe liver disease and HCV contributing to cardiovascular issues. Treating HCV in hypertensive patients is critical, though data on direct-acting antivirals (DAAs) in this group remain limited. Methods: This retrospective study evaluated the effects of DAAs in AH patients with HCV using data from the 2015–2023 EpiTer-2 project, a multicenter study in Poland. Results: Among the 18,968 HCV-infected DAA-treated patients, 5976 had AH. These patients were older, predominantly women, and had higher rates of obesity, comorbidities, cirrhosis, hepatocellular carcinoma, and genotype 1b infection. Sustained virologic response rates were high and comparable between the AH and non-AH groups in the intent-to-treat (94.8% vs. 94.2%) and per-protocol analyses (97.6% vs. 97.6%). AH was not independently associated with treatment failure (OR 0.87, 95% CI: 0.69–1.10). Predictors of failure included genotype 3, decompensated liver function, cirrhosis, thrombocytopenia, and treatment with asunaprevir + daclatasvir. While therapy discontinuation was more common in the AH patients, most completed treatment, with fatigue being the most frequent adverse event. Although not directly evaluated, the overall safety outcomes suggest that potential drug–drug interactions with antihypertensive therapies are unlikely to have a major clinical impact in routine practice. Conclusions: This study highlights the safety and efficacy of DAAs in AH patients and emphasizes the importance of early HCV detection and treatment in this population. Full article

Hepatitis E virus (HEV) infection is generally self-limiting in immunocompetent individuals but may progress to chronic infection in immunocompromised patients, underscoring the need for effective antiviral therapies. Although ribavirin is currently used off-label for HEV treatment, its associated adverse effects highlight the need for safer alternatives. In this study, we screened an anti-viral compound library comprising 800 compounds using three HEV reporter systems designed to target distinct stages of the viral life cycle. Candidate compounds were further evaluated in PLC/PRF/5 cells using both acute and chronic infection models with wild-type genotype 3 HEV (HEV-3). Antiviral activity was assessed by measuring HEV RNA levels in culture supernatants. Elbasvir, a known inhibitor of hepatitis C virus (HCV) non-structural protein 5A (NS5A), was identified as the most potent candidate. Although multiple compounds showed inhibitory effects in reporter assays, only elbasvir achieved sustained suppression of HEV growth in long-term culture, reducing HEV RNA levels to below the limit of detection. In a chronic infection co-culture model, elbasvir maintained antiviral activity at non-cytotoxic concentrations. Time-of-addition analysis demonstrated that elbasvir inhibits an early step in the viral life cycle, specifically viral internalization. Furthermore, combination with ribavirin enhanced antiviral efficacy, resulting in sustained viral suppression without detectable cytotoxicity and exhibiting an additive interaction. Collectively, these findings identify elbasvir as a promising candidate for repurposing as an anti-HEV drug and support a combination strategy targeting distinct steps of the viral life cycle. Full article

Direct-acting antivirals (DAAs) have revolutionized hepatitis C virus (HCV) therapy, yet resistance-associated substitutions (RASs) remain a concern in specific clinical contexts. Here, we present a database-derived global overview of HCV RASs by analyzing 19,449 publicly available sequences across multiple genotypes and subtypes, encompassing both untreated and previously treated infections, in the NS3, NS5A, and NS5B genomic regions. We demonstrate a markedly heterogeneous distribution of RASs shaped by viral genotype, geographic origin, and treatment era. Importantly, RASs against pan-genotypic NS3 protease inhibitors (glecaprevir and voxilaprevir) were rare (generally <1% across genotypes). In contrast, NS5A inhibitors showed greater vulnerability, with the Y93H substitution detected at notable frequencies in major genotypes (3.2–7.0%) and near-universal resistance-associated substitutions (e.g., 100% Q30S) observed in the rare genotype 8. The NS5B nucleotide analogue sofosbuvir retained a high genetic barrier, with the canonical S282T substitution detected only sporadically (2.1% of genotype 4 sequences). At the population level, geographic heterogeneity was evident, with higher RAS frequencies observed in specific regions, alongside pronounced data gaps in high-prevalence areas of Africa. Temporal analyses revealed an increase in NS3 and NS5A RASs following the introduction of first-generation DAAs, with NS5A substitutions persisting into the current interferon-free era, whereas NS5B resistance remained consistently rare across all treatment periods. Together, these findings provide a global, population-level overview of resistance-associated HCV diversity and reinforce the durability of high-barrier regimens while highlighting persistent genotype-specific vulnerabilities with implications for antiviral resistance surveillance and HCV elimination efforts. Full article

Background: The immunological factors associated with long-term hepatitis C virus (HCV)-specific humoral immunity after cure remain uncharacterized, particularly in people with HIV (PWH). This study investigated T-cell immunophenotypes and plasma biomarkers associated with anti-E2 binding (HCV-E2Abs) and neutralizing antibody (HCV-nAbs) titers 5 years after achieving sustained virologic response (SVR). Methods: This cross-sectional study analyzed 64 PWH with cured HCV and prior advanced fibrosis. We quantified plasma antibody titers against 5 HCV genotypes, T-cell phenotypes (n = 58), and plasma biomarkers (n = 50). Associations were assessed using Generalized Linear Models (gamma distribution, log-link function) adjusted for clinical confounders, reporting adjusted Arithmetic Mean Ratios (aAMRs) and false discovery rate (FDR)-corrected q-values. Results: Higher frequencies of CD4⁺ T-cell activation (CD38⁺; aAMR = 1.58; q = 0.028) and soluble CD27 levels (aAMR = 1.46; q = 0.038) were associated with higher HCV-E2Abs titers. In contrast, memory T-cell activation across CD4⁺ and CD8⁺ compartments (HLA-DR⁺ and CD38+; all q < 0.10) and elevated soluble immune checkpoints (sCD28, sPD-L2, sLAG-3, sCTLA-4; all q < 0.10) were associated with preserved HCV-nAbs titers. Conversely, a higher frequency of naïve CD8⁺ T-cells was associated with lower neutralization capacity (aAMR = 0.41; q = 0.042). Regarding inflammatory markers, soluble TNF-RI was positively associated with neutralizing titers (aAMR = 1.44; q = 0.019), whereas IL-18 was inversely associated (aAMR = 0.53; q = 0.019). Conclusions: Specific activated T-cell subsets, checkpoint shedding, and selective inflammatory signals were associated with higher long-term HCV-nAbs titers in PWH. In contrast, higher frequencies of naïve CD8⁺ T-cells and elevated IL-18 levels were associated with reduced neutralizing capacity. Full article

Hepatitis C virus (HCV) infection remains a major global health burden, and no vaccine preventing chronic infection is available. The envelope glycoproteins, E1 and E2, form a complex essential for viral entry; however, the mechanisms governing E1/E2 assembly and stability remain incompletely defined. Here, we investigated the role of the E1/E2 transmembrane (TM) regions in HCV infectivity using chimeras of JFH1-based recombinants with isolate-specific Core-NS2 sequences in which the C-terminal TM domains of E1 (TME1), E2 (TME2), or both (TME1E2) from the H77 isolate (genotype 1a) replaced those of isolates representing genotypes 1–6. We further introduced the TM domains of S52 (genotype 3a) or J6 (genotype 2a) into H77 and included reciprocal swaps between J6 and S52. Most TM-swap chimeras displayed impaired infectivity; however, serial passaging led to partial recovery associated with adaptive mutations in E1/E2 mapping not only to the C-terminal TM regions but also to the E1 stem and the internal E1 TM region (iTME1). Extending the TME1 swap to include upstream α-helical segments improved infectivity in selected chimeras, whereas inclusion of iTME1 abolished infectivity. These findings support functional interactions between membrane-associated regions of E1/E2 and their ectodomains and highlight their relevance for E1/E2-based HCV vaccine design. Full article

Background: Glucuronidation is a major phase II biotransformation reaction responsible for the inactivation and elimination of endogenous compounds and pharmaceuticals. This process is catalyzed by enzymes belonging to the UDP-glucuronosyltransferase (UGT) family, among which UGT1A1 is the most extensively studied. UGT1A1 plays a critical role in the metabolism of numerous drugs and is essential for bilirubin glucuronidation. Due to this specific function, it has significant clinical relevance, as impaired enzyme activity resulting from genetic polymorphisms or mutations can lead to the accumulation of unconjugated bilirubin in the bloodstream. This study aimed to evaluate the association between the UGT1A1*28 allele and the gene expression and protein levels in human liver tissue, in relation to different liver diseases. Methods: Liver tissues were obtained from patients with various liver pathologies and the control group consisted of tissues showing no pathological symptoms. A total of 143 patients were included in the study. Pyrosequencing was used to analyze PCR products for the UGT1A1*28 polymorphism (variable number of TA repeats in the TATA sequence of the promoter). Results: In both the control and study groups, UGT1A1 gene expression at the mRNA level and protein concentration in liver tissue decreased with the increasing number of UGT1A1*28 alleles. The association between UGT1A1 genotype and mRNA/protein content was most pronounced in HCV and AIH, and slightly weaker in the ALK and PBC groups. The significant association between UGT1A1*28 allele and bilirubin concentration was observed in control group but not in liver pathology. Conclusions: The UGT1A1*28 polymorphism is associated with reduced hepatic mRNA and protein abundance in patients with liver disease. However, the significance of this observation for the metabolism of the enzyme substrates should be further investigated. Full article

Hepatitis C virus (HCV) infection is still a major worldwide health concern. It is distinguished by a high degree of genetic variation that affects the course of the illness and the effectiveness of treatment. The epidemiological profile of HCV is prone to rapid change in areas where there is significant human migration, like Turkey. The purpose of this study was to evaluate the impact of long-term migration on local viral diversity by analyzing the distribution and temporal trends of HCV genotypes among Turkish citizens and asylum seekers in Kayseri, Turkey, over an eight-year period. From January 2014 to December 2021. 1173 HCV RNA-positive patients at Kayseri City Training and Research Hospital were the subject of a retrospective analysis. Genotypes were determined using the Abbott RealTime HCV Genotype II assay and Montania 4896 assay (Anatolia Geneworks, Türkiye). The most prevalent genotypes were Genotype 1b (48.3%, 95% CI: 45.5–51.2%), Genotype 4 (25.0%, 95% CI: 22.5–27.5%), and Genotype 1a (10.3%, 95% CI: 8.6–12.1%). Turkish patients exhibited the highest prevalence of Genotype 1b (98.2%), while asylum seekers demonstrated greater relative burdens of Genotype 4 (8.5% of total GT4) and Genotype 5 (83.3% of total GT5). Genotype 3a emerged in 2018, with a predominance in males (73.9%). The Cochran–Armitage trend test revealed statistically significant increasing trends for Genotype 3 (Z = 3.572, p = 0.0004) and Genotype 3a (Z = 2.600, p = 0.009). This eight-year retrospective study demonstrates that the HCV genotype distribution in Kayseri has undergone significant changes in the context of migration and demographic shifts. The statistically significant increasing trends of Genotypes 3 and 3a, particularly among younger male populations, suggest evolving transmission dynamics. These findings underscore the necessity of demographically targeted and culturally appropriate screening and treatment strategies for both resident and migrant populations to achieve HCV elimination goals. Full article

Although ombitasvir/paritaprevir/ritonavir plus dasabuvir (OPrD) therapy is highly effective for chronic hepatitis C (CHC), clinicians frequently encounter transient hyperbilirubinemia, which can be misidentified as hepatotoxicity. This study investigated the role of SLCO1B1 (OATP1B1) and SLCO1B3 (OATP1B3) genetic polymorphisms in predicting bilirubin spikes and distinguishing transporter-mediated interference from hepatocellular injury. In this prospective study of 65 patients with HCV genotype 1, genotyping for OATP1B1 (c.388A>G, c.521T>C) and OATP1B3 (c.334T>G, c.699G>A) was performed using PCR-RFLP and capillary electrophoresis (QIAxcel Advanced System). Clinical and biochemical parameters were monitored over a 12-week treatment period. Hyperbilirubinemia (total bilirubin >1.1 mg/dL) developed in 18.5% of the cohort, typically within the first month. A distinct ‘AST-dominant’ biochemical signature, elevated bilirubin and AST paired with stable ALT, was identified, suggesting transporter-specific interference rather than hepatocyte damage. Statistical analysis pinpointed the OATP1B3 c.699G>A (rs7311358) variant as the sole genetic driver (p = 0.007). Carriers of the c.699G>A allele faced a 6.3-fold higher risk of developing hyperbilirubinemia (OR: 6.30, 95% CI: 1.48–26.80, p = 0.032), while no significant associations were found for OATP1B1 variants. We conclude that OATP1B3 c.699G>A is a potent predictor of OPrD-induced hyperbilirubinemia. Identifying this genotype pre-treatment allows clinicians to anticipate transient, benign bilirubin elevations and prevent unnecessary drug discontinuation, thereby mitigating therapeutic inertia and ensuring treatment continuity for CHC patients. Full article

Hepatitis C virus (HCV) infection is a global health concern, chronically affecting over 71 million people. It primarily targets the liver but also causes systemic complications through inflammation, oxidative stress, and metabolic dysregulation. HCV is a highly variable RNA virus with six major genotypes that are mainly transmitted via blood. Often asymptomatic, the infection progresses silently to chronic hepatitis C (CHC), which can lead to fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Direct-acting antivirals (DAAs) have revolutionized treatment, achieving cure rates above 95%, improving liver function, reversing fibrosis, and normalizing metabolism. HCV disrupts iron metabolism by suppressing hepcidin, causing iron overload and oxidative stress. It also alters lipid metabolism, inducing steatosis, and affects glucose metabolism, contributing to insulin resistance and type 2 diabetes. DAAs improve these metabolic outcomes. HCV promotes oxidative stress via viral proteins, damaging liver cells and DNA and triggering inflammation and fibrogenesis. Even post-cure, oxidative stress and iron overload may continue to drive disease progression. Genetic and epigenetic factors influence fibrosis progression and HCC risk. Despite a sustained virologic response (SVR), patients with advanced liver damage remain at risk for HCC and metabolic diseases, highlighting the need for continued monitoring and personalized post-treatment care. Full article

Background/Objectives: This retrospective study investigates the prevalence and distribution of HCV genotypes among 233 genotyped patients from the Epirus region of Northwestern Greece from 2014 to 2024. Methods: Genotypes were detected by molecular diagnostic assays, and their association with demographic parameters and viral load was analyzed. Results: The most prevalent subtype was 3a (50.2%), especially among younger and male patients, followed by subtypes 1b and 1a. A statistically significant association was found between genotype and both age and sex, while genotype distribution did not significantly differ by national origin. Furthermore, subtype 6c-I was found only in a non-native case, suggesting a possible introduction of this rare strain. Viral load showed no significant difference by sex, genotype, or age group. A notable decline in HCV cases was documented during the COVID-19 pandemic, underscoring the impact of the public health crisis on HCV diagnosis. Despite the decreasing need for genotyping in the direct-acting antiviral (DAA) era, our findings support the continued molecular surveillance of circulating HCV strains. Conclusions: This is the first study to longitudinally assess HCV genotype dynamics over a full decade (2014–2024) in the Epirus region of Northwestern Greece, capturing trends during the COVID-19 era and documenting the emergence of rare genotypes. It contributes to the evolving knowledge of HCV epidemiology in Southeastern Europe. Full article

Hepatitis C virus (HCV) chronically infects over 50 million people worldwide and poses a significant risk to global health. The HCV NS3/4A complex, a bifunctional enzyme comprising a protease and a helicase domain, is indispensable for viral replication and immune evasion, making it a pivotal target for direct-acting antiviral agents (DAAs). Here, we summarize its structural features, functional mechanisms, and implications in drug design and protein engineering (e.g., nanopore sequencing applications). The NS3 protease domain is activated by the NS4A cofactor, which mediates viral polyprotein processing and relies on a zinc-binding site for structural stability. The C-terminal helicase domain catalyzes ATP-dependent 3′→5′ unwinding, and allosteric crosstalk between the protease and helicase domains dynamically modulates the enzymatic activity, balancing unwinding velocity and processivity. Beyond supporting viral replication, NS3/4A cleaves MAVS to abolish RIG-I/MDA5 signaling but spares TRIF, leaving TLR3-mediated immunity intact; it also modulates host lipid and iron metabolism, contributing to HCV pathogenesis. Notably, structural and functional studies of NS3/4A lay a solid theoretical foundation for developing novel therapeutic strategies. Currently, DAAs targeting NS3/4A have achieved high sustained virologic response rates; however, resistance-associated substitutions remain a major clinical challenge, particularly in genotype 3 infections. Emerging therapeutic strategies targeting NS3/4A include allosteric inhibition and proteolysis-targeting chimeras (PROTACs)-mediated degradation. Full article

Hepatitis C virus (HCV) still lacks a licensed vaccine. The envelope glycoprotein E2 is a key neutralizing target, but its dense N-glycan shield can hinder epitope exposure. In this study, we revisit E2 glycan editing and examine whether single-site deletion preserves antigen integrity while improving immune responses in mice under a DNA immunization setting. Using a secreted E2 ectodomain (sE2384–661), we generated five N to D mutants at conserved sites (N1, N2, N4, N6, and N11) and evaluated them in a unified DNA immunization model with identical CpG content and delivery conditions across groups. The N2 mutant (N423, sE2-N2) maintained expression, secretion, and ER localization; furthermore, in mice, it was associated with higher anti-E2 titers and greater inhibition of H77 (genotype 1a) HCVcc at the tested dilutions, with limited activity against Con1 (1b). Cellular analyses showed increased IFN-γ ELISPOT counts and higher frequencies of granzyme B⁺/perforin⁺ CD8⁺ T cells after N2 immunization, while IL-4 remained low. Functionally, N2 elicited stronger specific lysis of CT26-sE2 targets in vitro and slowed CT26-sE2 tumor growth in vivo. In HCV-infected ICR^4R+ mice, therapeutic vaccination with sE2-N2 reduced blood HCV RNA and hepatic readouts compared with sE2. A monoclonal antibody isolated from sE2-N2-immunized mice (1C1) neutralized HCVcc in vitro and, after passive transfer, lowered viremia and liver signals in infected mice. Collectively, these findings indicate that selective removal of the N2 glycan preserves antigen properties and is associated with improved humoral and cellular immunity and measurable in vivo activity, supporting targeted glycan editing as a practical strategy to refine E2-based HCV vaccines. Full article