Chronic Hepatitis C Virus Disease Research Articles

A Synopsis of Hepatitis C Virus Treatments and Future Perspectives.

Hepatitis C virus (HCV) infection is a worldwide public health problem. Chronic infection with HCV can lead to liver cirrhosis or cancer. Although some immune-competent individuals can clear the virus, others develop chronic HCV disease due to viral mutations or an impaired immune response. IFNs type I and III and the signal transduction induced by them are essential for a proper antiviral effect. Research on the viral cycle and immune escape mechanisms has formed the basis of therapeutic strategies to achieve a sustained virological response (SVR). The first therapies were based on IFNα; then, IFNα plus ribavirin (IFN-RBV); and then, pegylated-IFNα-RBV (PEGIFNα-RIV) to improve cytokine pharmacokinetics. However, the maximum SVR was 60%, and several significant side effects were observed, decreasing patients' treatment adherence. The development of direct-acting antivirals (DAAs) significantly enhanced the SVR (>90%), and the compounds were able to inhibit HCV replication without significant side effects, even in paediatric populations. The management of coinfected HBV-HCV and HCV-HIV patients has also improved based on DAA and PEG-IFNα-RBV (HBV-HCV). CD4 cells are crucial for an effective antiviral response. The IFNλ3, IL28B, TNF-α, IL-10, TLR-3, and TLR-9 gene polymorphisms are involved in viral clearance, therapeutic responses, and hepatic pathologies. Future research should focus on searching for strategies to circumvent resistance-associated substitution (RAS) to DAAs, develop new therapeutic schemes for different medical conditions, including organ transplant, and develop vaccines for long-lasting cellular and humoral responses with cross-protection against different HCV genotypes. The goal is to minimise the probability of HCV infection, HCV chronicity and hepatic carcinoma.

Study of glycated albumin to glycated hemoglobin ratio as a predictor of esophageal varices bleeding risk

Objectives To evaluate glycated albumin (GA) to glycated hemoglobin (HbA1c) ratio as a predictor of variceal bleeding in patients with liver cirrhosis. Background Variceal hemorrhage is a severe complication of liver cirrhosis and can be a direct cause of bleeding-related death. Therefore, upper endoscopy is considered necessary for all cirrhotic patients to evaluate the risk of variceal bleeding. Patients and methods A prospective clinical study was conducted on 100 patients with chronic hepatitis C-related cirrhosis who attended the Gastrointestinal Endoscopy Unit of the Department of Internal Medicine, Menoufia University hospitals, during the period between January 2017 and March 2018. Liver cirrhosis was diagnosed depending upon clinical examination in addition to laboratory and imaging studies. Various indicators for hepatic functions, HbA1c, and GA were measured. GA/HbA1c ratio was measured, and its relationship with the presence and bleeding risk of esophageal varices was analyzed. Results The GA/HbA1c ratio in hepatitis C virus (HCV)-positive cirrhotic patients increases with the severity of the esophageal varices. GA/HbA1c ratio may help in discrimination of low-risk from high-risk varices because GA/HbA1c ratio was the most significantly different among all of the other parameters tested; however, this is still doubtful. Conclusion Thrombocytopenia and prolonged prothrombin time parameters are associated with an increased risk of variceal bleeding. GA/HbA1c ratio in HCV-positive cirrhotic patients increases with the severity of the esophageal varices. GA/HbA1c ratio may help in discrimination of low-risk from high-risk varices. It is of interest and is not redundant to use the GA/HbA1c ratio to predict esophageal variceal bleeding risk in chronic HCV disease.

CD8+ T cells of chronic HCV-infected patients express multiple negative immune checkpoints following stimulation with HCV peptides

Hepatitis C virus (HCV)-specific CD4+ and CD8+ T cells are key to successful viral clearance in HCV disease. Accumulation of exhausted HCV-specific T cells during chronic infection results in considerable loss of protective functional immune responses. The role of T-cell exhaustion in chronic HCV disease remains poorly understood. Here, we studied the frequency of HCV peptide-stimulated T cells expressing negative immune checkpoints (PD-1, CTLA-4, TRAIL, TIM-3 and BTLA) by flow cytometry, and measured the levels of Th1/Th2/Th17 cytokines secreted by T cells by a commercial Multi-Analyte ELISArray™ following in vitro stimulation of T cells using HCV peptides and phytohemagglutinin (PHA). HCV peptide-stimulated CD4+ and CD8+ T cells of chronic HCV (CHC) patients showed significant increase of CTLA-4. Furthermore, HCV peptide-stimulated CD4+ T cells of CHC patients also displayed relatively higher levels of PD-1 and TRAIL, whereas TIM-3 was up-regulated on HCV peptide-stimulated CD8+ T cells. Whereas the levels of IL-10 and TGF-β1 were significantly increased, the levels of pro-inflammatory cytokines IL-2, TNF-α, IL-17A and IL-6 were markedly decreased in the T cell cultures of CHC patients. Chronic HCV infection results in functional exhaustion of CD4+ and CD8+ T cells likely contributing to viral persistence.

Peripheral loss of CD8(+) CD161(++) TCRVα7·2(+) mucosal-associated invariant T cells in chronic hepatitis C virus-infected patients.

Mucosal-associated invariant T (MAIT) cells play an important role in innate host defence. MAIT cells appear to undergo exhaustion and are functionally weakened in chronic viral infections. However, their role in chronic hepatitis C virus (HCV) infection remains unclear. We investigated the frequency of CD8(+) CD161(++) TCR Vα7.2(+) MAIT cells in a cross-sectional cohort of chronic HCV-infected patients (n = 25) and healthy controls (n = 25). Peripheral blood mononuclear cells were investigated for circulating MAIT cell frequency, liver-homing (CCR5 and CD103), biomarkers of immune exhaustion (PD-1, TIM-3 and CTLA-4), chronic immune activation (CD38 and HLA-DR), and immunosenescence (CD57) by flow cytometry. The frequency of MAIT cells was significantly decreased, and increased signs of immune exhaustion and chronic immune activation were clearly evident on MAIT cells of HCV-infected patients. Decrease of CCR5 on circulating MAIT cells is suggestive of their peripheral loss in chronic HCV-infected patients. MAIT cells also showed significantly increased levels of HLA-DR, CD38, PD-1, TIM-3 and CTLA-4, besides CD57 in chronic HCV disease. Immune exhaustion and senescence of CD8(+) CD161(++) TCR Vα7.2(+) MAIT cells could contribute to diminished innate defence attributes likely facilitating viral persistence and HCV disease progression.

A frequent hypofunctional IRAK2 variant is associated with reduced spontaneous hepatitis C virus clearance.

Patients carrying very rare loss-of-function mutations in interleukin-1 receptor-associated kinase 4 (IRAK4), a critical signaling mediator in Toll-like receptor signaling, are severely immunodeficient, highlighting the paramount role of IRAK kinases in innate immunity. We discovered a comparatively frequent coding variant of the enigmatic human IRAK2, L392V (rs3844283), which is found homozygously in ∼15% of Caucasians, to be associated with a reduced ability to induce interferon-alpha in primary human plasmacytoid dendritic cells in response to hepatitis C virus (HCV). Cytokine production in response to purified Toll-like receptor agonists was also impaired. Additionally, rs3844283 was epidemiologically associated with a chronic course of HCV infection in two independent HCV cohorts and emerged as an independent predictor of chronic HCV disease. Mechanistically, IRAK2 L392V showed intact binding to, but impaired ubiquitination of, tumor necrosis factor receptor-associated factor 6, a vital step in signal transduction. Our study highlights IRAK2 and its genetic variants as critical factors and potentially novel biomarkers for human antiviral innate immunity.

Chronic hepatitis C virus infection triggers spontaneous differential expression of biosignatures associated with T cell exhaustion and apoptosis signaling in peripheral blood mononucleocytes.

Persistent hepatitis C virus (HCV) infection appears to trigger the onset of immune exhaustion to potentially assist viral persistence in the host, eventually leading to hepatocellular carcinoma. The role of HCV on the spontaneous expression of markers suggestive of immune exhaustion and spontaneous apoptosis in immune cells of chronic HCV (CHC) disease largely remain elusive. We investigated the peripheral blood mononuclear cells of CHC patients to determine the spontaneous recruitment of cellular reactive oxygen species (cROS), immunoregulatory and exhaustion markers relative to healthy controls. Using a commercial QuantiGenePlex(®) 2.0 assay, we determined the spontaneous expression profile of 80 different pro- and anti-apoptotic genes in persistent HCV disease. Onset of spontaneous apoptosis significantly correlated with the up-regulation of cROS, indoleamine 2,3-dioxygenase (IDO), cyclooxygenase-2/prostaglandin H synthase (COX-2/PGHS), Foxp3, Dtx1, Blimp1, Lag3 and Cd160. Besides, spontaneous differential surface protein expression suggestive of T cell inhibition viz., TRAIL, TIM-3, PD-1 and BTLA on CD4+ and CD8+ T cells, and CTLA-4 on CD4+ T cells was also evident. Increased up-regulation of Tnf, Tp73, Casp14, Tnfrsf11b, Bik and Birc8 was observed, whereas FasLG, Fas, Ripk2, Casp3, Dapk1, Tnfrsf21, and Cflar were moderately up-regulated in HCV-infected subjects. Our observation suggests the spontaneous onset of apoptosis signaling and T cell exhaustion in chronic HCV disease.

Hepatitis C virus infection contributes to impregnation of markers of immune inhibition: potential preludes underlying viral latency and persistence

Background Hepatitis C virus (HCV) represents one of the persistent viral infections afflicting humankind, and a significant proportion of chronic HCV disease progresses over time through liver fibrosis, cirrhosis and hepatocellular carcinoma (HCC). One potential mechanism underlying the chronic disease is believed to be viral escape from immune surveillance via upregulation of inhibitory molecules on immune cells by HCV. We investigated the diverse expression of various inhibitory molecules in PBMCs of healthy non-HCV controls and chronically HCV infected patients. Methods The expression of inhibitory molecules on PBMCs was investigated in chronic HCV infected patients relative to healthy non-HCV controls using standard immunological and molecular methods. The serum levels of indoleamine 2, 3 deoxygenase (IDO) and cyclooxygenase-2 (COX-2) were also investigated. Results The gene expression profile of chronically HCV infected patients was significantly different from control individuals. Our results showed upregulation of TIM-3 (p≤0.01), PD-1 (p≤0.01), FOXP-3 (p≤0.01), BLIMP-1 (p≤0.01), CD160 (p≤0.01), CTLA-4 (p≤0.01), TRAIL (p≤0.01), BTLA (p≤0.01) and LAG-3 (p≤0.01) with fold change of 1.3, 0.4, 14.6, 0.87, 6.6, 0.4, 14.7, 10.9 and 2.5 respectively in chronically HCV infected patients. The plasma IDO and COX-2 levels were significantly higher (p=0.001) in chronically HCV infected subjects relative to healthy control. Conclusion

Cost-effectiveness of telaprevir in combination with pegylated interferon alpha and ribavirin in previously untreated chronic hepatitis C genotype 1 patients

Background:Telaprevir (T, TVR) is a direct-acting antiviral (DAA) used for the treatment of genotype 1 chronic hepatitis C virus (HCV) infection. The sustained virological response (SVR) rates, i.e., undetectable HCV RNA levels 24 weeks after the end of treatment, is what differentiate treatments. This analysis evaluated the cost-effectiveness of TVR combined with pegylated interferon (Peg-IFN) alfa-2a plus ribavirin (RBV), with Peg-IFN and RBV (PR) alone or with boceprevir (B, BOC) plus Peg-IFN alfa-2b and RBV, in naïve patients.Methods:A Markov cohort model of chronic HCV disease progression reflected the pathway of naïve patients initiating anti-HCV therapy. SVR rates were derived from a mixed-treatment comparison including results from Phase II and III trials of TVR and BOC, and trials comparing both PR regimens. SVR has significant impact on survival, quality-of-life, and costs. Incremental cost per life year (LY) gained and quality-adjusted-life-year (QALY) gained were computed at lifetime, adopting the (National Health Service) NHS perspective. Cost and health outcomes were discounted at 3.5%. Uncertainty was assessed using deterministic and probabilistic sensitivity analyses. Sub-group analyses were also performed by interleukin (IL)-28B genotype and fibrosis stage.Results:Higher costs and improved outcomes were associated with T/PR relative to PR alone, resulting in an ICER of £12,733 per QALY gained. T/PR retained a significant SVR advantage over PR alone and was cost-effective regardless of IL-28B genotype and fibrosis stages. T/PR regimen ‘dominated’ B/PR, generating 0.2 additional QALYs and reducing lifetime cost by £2758. Sensitivity analyses consistently resulted in ICERs less than £30,000/QALY for the T/PR regimen over PR alone.Limitations:No head-to-head trial provides direct evidence of better efficacy of T/PR vs B/PR.Conclusion:The introduction of TVR-based therapy for genotype 1 HCV patients is cost-effective for naïve patients at the £30,000 willingness-to-pay threshold, regardless of IL-28B genotype or fibrosis stage.

Insulin resistance, steatosis, and fibrosis in Egyptian patients with chronic Hepatitis C virus infection

Background/Aim:Both nonalcoholic fatty liver disease (NAFLD) and chronic hepatitis C virus (HCV) infection are common in Egypt, and their coexistence is expected. There is controversy regarding the influence of NAFLD on chronic HCV disease progression. This study evaluates the effect of NAFLD on the severity of chronic hepatitis C (CHC) (necroinflammation and fibrosis) and assesses the relative contribution of insulin resistance syndrome to the occurrence of NAFLD in patients with chronic HCV infection.Patients and Methods:Untreated consecutive adults with chronic HCV infection admitted for liver biopsy were included in this study. Before liver biopsy, a questionnaire for risk factors was completed prospectively, and a blood sample was obtained for laboratory analysis.Results:Our study included 92 male patients. Their mean ± SD age and aspartate aminotransferase (AST) level were 42 ± 7.7 years (range 20-56) and 68 ± 41.7 U/L (range 16-214), respectively. The mean insulin level and insulin resistance index were 15.6 ± 18.3 mIU/mL (range 5.1-137.4) and 5.9 ± 15.2 (range 0.9-136.2), respectively. Fifty four percent of patients had steatosis and 65% had fibrosis. In multivariate analyses, steatosis was associated with insulin resistance and fibrosis was associated with high AST level, age ≥40 years, and steatosis.Conclusions:Steatosis is a histopathologic feature in >50% of patients with chronic HCV infection. Insulin resistance has an important role in the pathogenesis of steatosis, which represents a significant determinant of fibrosis together with high serum AST level and older age.

Clinical outcomes in a prospective study of community-acquired hepatitis C virus infection in Northern Norway

Objective. Knowledge on the natural course of the morbidity of unselected community-acquired hepatitis C virus (HCV) infection is limited. The aim of our study was to characterize the clinical outcomes of both hepatic and extrahepatic morbidity in patients infected with HCV in a community-based setting in Northern Norway. Material and methods. This prospective cohort study included 1010 HCV-positive patients diagnosed by recombinant immunoblot assay (RIBA), between 1 January 1990 and 1 January 2000. Questionnaires were sent to those physicians in Northern Norway who had requested the RIBA tests during the relevant period. Data were collected from medical records in the period between 1 January 2004 and 30 June 2006. Access to confidential information was obtained from the Norwegian Directorate of Health. Results. Median age at follow-up was 39 and 41 years in females and males, respectively. In patients with positive HCV RNA status following results were found: Alanine aminotransferase was elevated in 27.4%, decompensated liver disease in 2.9% and hepatocellular carcinoma in 0.4%. Median observation period from estimated acquisition of the disease to follow-up in these patients was 26 years. Depression was reported in 10.7% of chronic infected subjects. Renal failure caused by membranoproliferative glomerulonephritis occurred in 0.2%. Conclusions. In an unselected HCV-RNA positive population severe liver disease developed in a sub-group of patients. These observations suggest that chronic HCV disease in relatively young subjects may cause a substantial burden on the health system in the future.

Hepatocellular MxA protein expression supports the differentiation of recurrent hepatitis C disease from acute cellular rejection after liver transplantation

Differentiation of recurrent hepatitis C virus (HCV) disease from acute cellular rejection (ACR) following liver transplantation can be difficult. Previously, we have found that MxA protein, a specific and sensitive marker for type 1 interferon production, is strongly expressed in chronic HCV disease. Here, we investigate MxA expression as a marker for recurrent HCV disease in the livers of 14 adult HCV patients who underwent liver transplantation. Serial liver biopsies available for 12 of these patients were stained for MxA protein and scored using a semi-quantitative approach. Hepatocellular MxA protein levels were significantly up-regulated (p = 0.025) in recurrent HCV disease in comparison to ACR. In biopsies that showed histological changes consistent with recurrent HCV disease, strong hepatocellular MxA staining was present in 14/18 (78%). In the liver biopsies with histological evidence of ACR, strong MxA hepatocellular staining was present in only three of 10 (30%). Thus, assessment of hepatocellular MxA protein expression can contribute to the differential diagnosis of ACR and recurrent HCV disease following liver transplantation. In conclusion, analysis of intrahepatic MxA levels has the potential to reduce the inappropriate use with high-dose pulsing of steroids post-operatively.

Genotype-dependent sensitivity of hepatitis C virus to inhibitors of the p7 ion channel

The hepatitis C virus (HCV) p7 protein plays a critical role during particle formation in cell culture and is required for virus replication in chimpanzees. The discovery that it displayed cation channel activity in vitro led to its classification within the "viroporin" family of virus-coded ion channel proteins, which includes the influenza A virus (IAV) M2 protein. Like M2, p7 was proposed as a potential target for much needed new HCV therapies, and this was supported by our finding that the M2 inhibitor, amantadine, blocked its activity in vitro. Since then, further compounds have been shown to inhibit p7 function but the relationship between inhibitory effects in vitro and efficacy against infectious virus is controversial. Here, we have sought to validate multiple p7 inhibitor compounds using a parallel approach combining the HCV infectious culture system and a rapid throughput in vitro assay for p7 function. We identify a genotype-dependent and subtype-dependent sensitivity of HCV to p7 inhibitors, in which results in cell culture largely mirror the sensitivity of recombinant protein in vitro; thus building separate sensitivity profiles for different p7 sequences. Inhibition of virus entry also occurred, suggesting that p7 may be a virion component. Second site effects on both cellular and viral processes were identified for several compounds in addition to their efficacy against p7 in vitro. Nevertheless, for some compounds antiviral effects were specific to a block of ion channel function. These data validate p7 inhibitors as prototype therapies for chronic HCV disease. (HEPATOLOGY 2008;48:1779-1790.).

Hepatitis C virus chronic infection and oral lichen planus: an Italian case–control study

The aim of the study was to investigate the possible epidemiological relationship between hepatitis C virus (HCV) chronic infection and oral lichen planus (OLP) in centre-south Italy. In a case-control study three groups of patients were investigated: group 1 (82 patients): patients with histologically confirmed OLP were tested for HCV infection; group 2 (165 patients): patients with chronic HCV infection were examined for OLP; group 3 (466 participants): control group: healthy individuals who had been hospitalized in the Trauma-Orthopaedic Ward and had been tested for HCV. In group 1, 11.4% of the participants were HCV-positive and HCV was found in 10.8% of the patients above 50 years of age. Eight participants (5.5%) of group 2 showed lesions possibly related to OLP: only two had a histology consistent with OLP. In group 3, 5.4% participants had chronic HCV infection, but HCV was found in 10% of the participants of 50 years and above. A weak overall association between HCV and OLP (odds ratio 2.27; 95% confidence interval 0.94, 5.35; P<0.05) was seen and the result was not statistically significant in participants aged 50 years and above (odds ratio 1.08; 95% confidence interval 0.39, 2.88; P=0.86). Our data suggest that no clear association exists between OLP and chronic HCV disease. It is possible that the association is mainly due to the frequency of each disease in the population.

Morphine Inhibits Intrahepatic Interferon‐α Expression and Enhances Complete Hepatitis C Virus Replication

Heroin addicts are a high-risk group for hepatitis C virus (HCV) infection and the development of chronic HCV disease. We thus examined whether morphine, the active metabolite of heroin, has the ability to inhibit intrahepatic interferon (IFN)- alpha expression, facilitating HCV replication in human hepatocytes. Morphine inhibited intrahepatic IFN- alpha expression, which was associated with an increase in HCV replication in hepatocytes. Moreover, morphine compromised the anti-HCV effect of recombinant IFN- alpha . Investigation of the mechanism responsible for the morphine action revealed that morphine inhibited expression of IFN regulatory factor 5 in the hepatocytes. In addition, morphine suppressed the expression of p38, an important signal-transducing molecule involved in IFN- alpha -mediated anti-HCV activity. These findings indicate that morphine plays a cofactor role in facilitating HCV persistence in human hepatocytes.

Genetic variants of the IgA Fc receptor (FcαR, CD89) promoter in chronic hepatitis C patients

Fc receptor for IgA (FcalphaR, CD89) is capable of triggering IgA-mediated immune responses to pathogens and has been proposed to function in circulating IgA clearance. Because inheritable variations modifying individual immune responses or immunoglobulin catabolism may affect the chronicity of viral infection, we investigated whether promoter polymorphisms of the FcalphaR gene (FCAR) affect chronic hepatitis C virus (HCV) infection and its disease progression. The two -311T/C and -142T/C single-nucleotide polymorphisms (SNPs) were studied by direct DNA sequencing in 177 Japanese patients with chronic hepatitis C (CHC). Both -311CC and -142CC genotypes were more frequent in CHC patients (15.9 and 18.6%) compared with 210 healthy controls (5.7 and 10.0%) [p = 0.001, odds ratio (OR) = 3.10, 95% confidence interval CI) = 1.53-6.30 and p = 0.014, OR = 2.06, 95% CI = 1.14-3.72, respectively], and were associated with infection with HCV genotype 2a/2b (p = 0.019 and p = 0.005, respectively). Conversely, -311CC and -142CC were decreased in 59 patients at advanced stages of disease as assessed on the basis of hepatic fibrosis markers such as decreased platelet count (PLT) (< 150,000/microl) (5.1 and 8.5%) compared with 91 patients with normal PLT (> or = 150,000/microl) (24.2 and 26.4%) (p = 0.006 and p = 0.005, respectively). Moreover, among the patients with normal PLT (but not with decreased PLT), -311CC or -142CC was significantly associated with decreased serum IgA levels (p = 0.023 or p = 0.007, respectively). These results suggest that the FCAR promoter SNPs may be related to chronic HCV infection and disease progression in Japanese CHC, which might be explained by altered FcalphaR expression affecting IgA-mediated immune responses and/or IgA catabolism.

Outcome after orthotopic liver transplantation in five HIV‐infected patients with virus hepatitis‐induced cirrhosis

We report on our experiences with orthotopic liver transplantation (OLT) in HIV-infected patients. Between July 1998 and October 2001, five HIV-infected patients underwent OLT because of virus-induced liver cirrhosis. One patient suffered from hepatitis B virus (HBV)-, three patients from hepatitis C virus (HCV)- and one patient from HCV/HBV/HDV-related cirrhosis (HDV, hepatitis D virus). The mean duration of HIV infection was 15 years. Patients were prospectively followed up with a mean duration of 25.6 months. Three patients died 3, 10 and 31 months after OLT, respectively, due to graft failure. The causes of graft failure were: recurrent thrombosis of the hepatic artery, HCV-associated cholestatic hepatitis and chemotherapy-induced liver damage due to Hodgkin's disease, which was diagnosed 17 months after OLT, in addition to chronic HCV disease. The two survivors show a stable liver function and non-progredient HIV infection under antiretroviral therapy 61 and 23 months after OLT, respectively. A medium- or even long-term survival after OLT can be achieved in HIV-infected patients without progression of HIV disease under antiretroviral therapy. However, in our study three out of five patients died due to graft failure. Therefore, prognostic criteria have to be defined for the selection of HIV-infected patients, who may benefit from OLT.

What is disrupting IFN-α's antiviral activity?

Despite advances in treatment strategies for hepatitis C virus (HCV), a significant proportion of patients fail to achieve viral clearance following treatment with pegylated interferon (IFN)-α plus ribavirin. Many of these individuals show elevated levels of tumor necrosis factor (TNF)-α compared with normal controls, and recent data have implicated this cytokine in the negative regulation of IFN-α. Although a therapeutic opportunity for TNF-α antagonists might exist for reducing inflammation in chronic HCV disease, further exploration is required to identify the key mediators of responsiveness to IFN-α. In particular, the interplay should be clarified between host response factors [e.g. IFN-α, IFN-γ, suppressor of cytokine signaling (SOCS), TNF-α and others] and pathogen-associated molecular patterns [PAMPs, e.g. lipopolysaccharide (LPS) and CpG DNA] in HCV disease; this information might guide future therapies aimed at improving IFN-α responsiveness.

Histopathologic and immunocytochemical changes in the liver in patients with chronic hepatitis C

The presence of lymphocytes within the liver parenchyma is related to immunologically mediated liver damage in chronic hepatitis C. The aim of the study was to make histological, histochemical, and immunocytochemical assessment of liver biopsy specimens in patients with chronic hepatitis C virus (HCV) infection. Biopsy specimens of 20 patients with chronic HCV disease were analyzed, using standard staining procedures to verify histologic liver lesions, as well as immunoenzymatic staining with monoclonal antibodies to detect CD4+ T-lymphocytes, B-lymphocytes, and macrophages. Micromorphologic characteristics of chronic active viral hepatitis C were present in all the patients, differing, however, by the level of their activity. Dominant changes were found within the portal space, consisting of mononuclear lympho-plasmocytic infiltration and macrophages. Immunocytochemical investigation of mononuclear and macrophageal infiltration showed the correlation between micromorphological findings and the degree of the activity. The presence of lymphocytic and macrophageal infiltration within the hepatic tissue directly correlated with the intensity of the liver damage. Analysis of the population of cellular infiltrate in the liver together with the monitoring of viremia level and the level of hepatocyte necrosis, could be useful tools for elucidation of the pathogenesis of chronic hepatitis C.

Impact of immunosuppression on immunopathogenesis of liver damage in hepatitis C virus-infected recipients following liver transplantation

1. Hepatitis C virus (HCV) infection in the allograft occurs in the setting of greater viral burdens than in patients pretransplantation. 2. Viral burden is increased by such immunosuppressive therapies as corticosteroids and interleukin-2 receptor antibodies. 3. Cholestatic HCV infection occurs in the setting of very high viral load and is almost certainly induced by overimmunosuppression. It is managed best by rapid reduction in levels of immunosuppression. 4. The more common chronic hepatitic HCV disease seems to behave at the molecular/cellular level in a fashion similar to the nontransplantation setting with activation of T helper subtype 1 inflammatory, profibrotic, and proapoptotic pathways. The role of immunosuppression in the acceleration of this disease is unclear, and rapid reduction in immunosuppressive doses may be detrimental. 5. Changes to definitions of types of HCV disease recurrence, disease severity, and acute allograft rejection in the presence of HCV infection are required to improve understanding of the pathogenesis.

Identification and Biological Characterization of Heterocyclic Inhibitors of the Hepatitis C Virus RNA-dependent RNA Polymerase

The hepatitis C virus (HCV) NS5B protein encodes an RNA-dependent RNA polymerase (RdRp), the primary catalytic enzyme of the HCV replicase complex. We established a biochemical RNA synthesis assay, using purified recombinant NS5B lacking the C-terminal 21 amino acid residues, to identify potential polymerase inhibitors from a high throughput screen of the GlaxoSmithKline proprietary compound collection. The benzo-1,2,4-thiadiazine compound 1 was found to be a potent, highly specific inhibitor of NS5B. This agent interacts directly with the viral polymerase and inhibits RNA synthesis in a manner noncompetitive with respect to GTP. Furthermore, in the absence of an in vitro-reconstituted HCV replicase assay employing viral and host proteins, the ability of compound 1 to inhibit NS5B-directed viral RNA replication was determined using the Huh7 cell-based HCV replicon system. Compound 1 reduced viral RNA in replicon cells with an IC(50) of approximately 0.5 microm, suggesting that the inhibitor was able to access the perinuclear membrane and inhibit the polymerase activity in the context of a replicase complex. Preliminary structure-activity studies on compound 1 led to the identification of a modified inhibitor, compound 4, showing an improvement in both biochemical and cell-based potency. Lastly, data are presented suggesting that these compounds interfere with the formation of negative and positive strand progeny RNA by a similar mode of action. Investigations are ongoing to assess the potential utility of such agents in the treatment of chronic HCV disease.