Hepatitis C virus RNA in peripheral blood mononuclear cells: comparing acute and chronic hepatitis C virus infection

miR-122 affects both the initiation and maintenance of Hepatitis C Virus infections

A liver-specific microRNA, miR-122, anneals to the HCV genomic 5' terminus and is essential for virus replication in cell culture. However, bicistronic HCV replicons and full length RNAs with specific mutations in the 5' UTR can replicate, albeit to low levels, without miR-122. In this study, we have identified that HCV RNAs lacking the structural gene region or having EMCV IRES-regulated translation had reduced requirements for miR-122. In addition, we found that a smaller proportion of cells supported miR-122-independent replication when compared a population of cells supporting miR-122-dependent replication, while viral protein levels per positive cell were similar. Further, the proportion of cells supporting miR-122-independent replication increased with the amount of viral RNA delivered, suggesting that establishment of miR-122-independent replication in a cell is affected by amount of viral RNA delivered. HCV RNAs replicating independent of miR-122 were not affected by supplementation with miR-122, suggesting that miR-122 is not essential for maintenance of a miR-122-independent HCV infection. However, miR-122 supplementation had a small positive impact on miR-122-dependent replication suggesting a minor role in enhancing ongoing virus RNA accumulation. We suggest that miR-122 functions primarily to initiate an HCV infection but has a minor influence on its maintenance, and we present a model in which miR-122 is required for replication complex formation at the beginning of an infection, and also supports new replication complex formation during ongoing infection and after infected cell division. IMPORTANCE: The mechanism by which miR-122 promotes the HCV life cycle is not well understood, and a role in directly promoting genome amplification is still debated. In this study, we have shown that miR-122 increases the rate of viral RNA accumulation and promotes the establishment of an HCV infection in a greater number of cells than in the absence of miR-122. However, we also confirm a minor role in promoting ongoing virus replication and propose a role in the initiation of new replication complexes throughout a virus infection. This study has implications for the use of anti-miR-122 as potential HCV therapy.

Expression of TRIM22 mRNA in chronic hepatitis C patients treated with direct-acting antiviral drugs

Hepatitis C is a global public health problem, and Pakistan is the second largest country in the globe with highest prevalence rate of hepatitis C virus (HCV). Until 2014, pegylated interferon (PEG-IFN) plus ribavirin (RBV) has been the standard therapy for HCV, however, owing to its adverse side effects and very low sustained virologic response (SVR) rates therapeutics trend is shifted toward direct-acting antivirals. Tripartite motif containing 22 (TRIM22) is a dynamic antiviral protein that can inhibit multiple viruses in vivo. Expression of TRIM22 mRNA has been linked to outcome of PEG-IFN and ribavirin therapy, where its higher expression leads to rapid virus clearance. However, in terms of therapy with direct-acting antiviral (DAA) or double DAA, impact of TRIM22 expression is largely unknown. These new drugs show more than 90% of SVR rates and lesser side effects and have proven to be better than IFN therapy. Endogenous IFN system suppresses various pathogens through the induction of antiviral effectors termed as interferon-stimulating genes (ISGs). We have studied the expression levels of one of these antiviral effectors, TRIM22 in response to sofosbuvir (SOF) and daclatasvir (DAC) in combination with RBV, using quantitative PCR in the peripheral blood mononuclear cells (PBMCs) of HCV-infected patients. We have observed sustained virus clearance in more than 90% of patients treated with DAA and double DAA and have seen the expression of TRIM22 to be higher in patients who attained SVR as compared to the untreated patients. We have also observed downregulation of TRIM22 in patients who failed to attain rapid virus clearance, and upregulation in those who achieved rapid clearance of virus. Genetic factors that determine the lower TRIM22 expression in these patients are needed to be explored that may also play a role in lower response to anti-HCV therapy. Endogenous IFN system and effects of antiviral proteins in response to DAA therapy is needed to be studied in order to better understand the host response toward these drugs to make them more effective.

Determinants of Infection Outcome in HCV-Genotype 4

Hepatitis C virus (HCV) infection represents a worldwide health problem and has been for long an attractive point of research due to diversity among different genotypes regarding unique geographical distribution and diverse treatment outcome. HCV is considered a major cause of chronic liver disease and cirrhosis, which leads to liver failure and hepatocellular carcinoma requiring liver transplantation. Of the HCV genotypes identified, HCV genotype 4 (HCV-4) is the least studied. HCV-4 is responsible for ∼10% of HCV infections and is common in the Middle East and Africa; recently it is increasingly prevalent in European Countries. HCV-4 is a continuing epidemic in Egypt, having the highest prevalence of HCV worldwide. "Know your epidemic, know your response" concept necessitates better understanding of HCV-4 characteristics to control disease dissemination and progression, which compromises the life quality of chronic HCV-infected patients. In this review, we discuss the epidemiology, natural history, and treatment options for patients with HCV-4 infection.

Extra-hepatic infection of hepatitis C virus in the colon tissue and its relationship with hepatitis C virus pathogenesis

Extra-hepatic compartments might contribute to hepatitis C virus (HCV) persistence and extra-hepatic manifestations. Therefore, we investigated HCV infection in colonic tissue in patients with chronic hepatitis C (CHC) and its relationship with HCV pathogenesis. Colonic biopsies were collected from three groups with CHC infection: treatment naïve (TN; n=12), non-responders (NR; n=10) to anti-HCV therapy (pegylated interferon-α and ribavirin) and sustained virologic response (SVR; n=10) and from a fourth healthy control group (n=10). Liver biopsies were examined to assess inflammation and fibrosis. HCV infection and colonic T regulatory (Treg) frequency were detected by immunohistochemistry. HCV core and NS3 proteins were detected in B cells and macrophage/monocytes of 42 % and 25 % of TN and 50 % and 30 % of NR, respectively, but not in SVR or control group. The numbers of cells expressing HCV proteins were positively correlated with both HCV viral load and colonic Treg frequency. A significant negative correlation between HCV-expressing cells with both liver inflammation and fibrosis was identified. Our study provides evidence that HCV can infect B cells and macrophages of the colon. The correlations between HCV infection in colonic tissue and HCV viral load and liver pathology underline the significance of this extra-hepatic infection in HCV pathogenesis and response to therapy.

Gut immune response in the presence of hepatitis C virus infection

Hepatitis C virus (HCV) is an important etiologic agent of hepatitis and a major cause of chronic liver infection that often leads to cirrhosis, fibrosis and hepatocellular carcinoma. Although, HCV is a hepatotropic virus, there is strong evidence that HCV could replicate extra-hepatic in the gastrointestinal tissue which could serve as a reservoir for HCV. The outcome of HCV infection depends mainly on the host innate and adaptive immune responses. Innate immunity against HCV includes mainly nuclear factor cells and activation of IFN-related genes. There is an immunologic link between the gut and the liver through a population of T-cells that are capable of homing to both the liver and gut via the portal circulation. However, little is known on the role of Gut immune response in HCV. In this review we discussed the immune regulation of Gut immune cells and its association with HCV pathogenesis, various outcomes of anti-HCV therapy, viral persistence and degree of liver inflammation. Additionally, we investigated the relationship between Gut immune responses to HCV and IL28B genotypes, which were identified as a strong predictor for HCV pathogenesis and treatment outcome after acute infection.

Quantitation of hepatitis C virus RNA in peripheral blood mononuclear cells in HCV-monoinfection and HIV/HCV-coinfection

Peripheral blood mononuclear cells (PBMCs) represent an extrahepatic hepatitis C virus (HCV) reservoir, the significance of which is unclear due to limited studies and varying test methodologies. In this study, a commercial viral load assay for measuring cell-associated PBMC HCV RNA was evaluated. HCV RNA was extracted from PBMCs, sorted CD14+, and CD19+ cells and corresponding plasma samples using the Abbott m2000 and Real-Time HCV assay. Test performance and influence of HIV seropositivity on plasma and PBMC HCV RNA were studied. Among 51 patients, 67 and 62 unique patient samples had detectable plasma and PBMC HCV viral load, respectively. The median PBMC viral load was 535 IU/1 M cells (range 29-5,190). CD19+ cells had significantly higher viral load than CD14+ cells (median log(10) HCV viral load 2.63 vs. 1.50 IU/ml; P< 0.001). Stability of PBMC viral load over time was demonstrated in untreated patients; all patients with an undetectable plasma HCV viral load after HCV treatment also demonstrated undetectable PBMC viral load. Repeated testing in nine samples yielded consistent PBMC viral load, differing by only 1.3-fold (range 1.0-1.7-fold). Among samples with detectable plasma HCV RNA, the correlation between PBMC and plasma viral load was moderate (r = 0.66) and was greater among HCV mono-infected compared to HIV/HCV co-infected subjects (r = 0.80 vs. 0.52). Measurement of cell-associated PBMC HCV RNA using a commercial assay demonstrated promising test characteristics. Differences in PBMC HCV viral load based on HIV-coinfection status and the significance of greater copy number in B-cells requires further study.

Interferon combination therapy for HIV/hepatitis C virus coinfection

IFN-α has been the cornerstone of chronic hepatitis C virus (HCV) treatment for over a decade. Yet, rates of sustained virologic response of HCV infection to interferon-based therapy, particularly in difficult-to-treat populations, have been disappointingly low. This is particularly true in HIV/HCV coinfection, in which less than a third of patients typically respond to therapy. New HCV protease inhibitors, most of which will need to be administered with pegylated interferon, are in development, but comprehensive, long-term data for their use in coinfected patients is not yet available. Understanding the basis of this population's poor response to interferon-based therapy is crucial to future exploration of new therapeutic options, immunotherapy and prognosis in HIV/HCV-coinfected population.

Human cell types important for hepatitis C virus replication in vivo and in vitro: old assertions and current evidence

Hepatitis C Virus (HCV) is a single stranded RNA virus which produces negative strand RNA as a replicative intermediate. We analyzed 75 RT-PCR studies that tested for negative strand HCV RNA in liver and other human tissues. 85% of the studies that investigated extrahepatic replication of HCV found one or more samples positive for replicative RNA. Studies using in situ hybridization, immunofluorescence, immunohistochemistry, and quasispecies analysis also demonstrated the presence of replicating HCV in various extrahepatic human tissues, and provide evidence that HCV replicates in macrophages, B cells, T cells, and other extrahepatic tissues. We also analyzed both short term and long term in vitro systems used to culture HCV. These systems vary in their purposes and methods, but long term culturing of HCV in B cells, T cells, and other cell types has been used to analyze replication. It is therefore now possible to study HIV-HCV co-infections and HCV replication in vitro.

Analysis of the 5'UTR of HCV genotype 3 grown in vitro in human B cells, T cells, and macrophages

Background

Previously, we have reported the isolation and molecular characterization of human Hepatitis C virus genotype 1 (HCV-1) from infected patients. We are now reporting an analysis of HCV obtained from patients infected with HCV genotype 3 (HCV-3) as diagnosed by clinical laboratories.

Results

HCV was cultured in vitro using our system. HCV RNA was isolated from patients' blood and from HCV cultured in various cell types for up to three months. The 5'UTR of these isolates were used for comparisons. Results revealed a number of sequence changes as compared to the serum RNA. The HCV RNA produced efficiently by infected macrophages, B-cells, and T-cells had sequences similar to HCV-1, which suggests that selection of the variants was performed at the level of macrophages. Virus with sequences similar to HCV-1 replicated better in macrophages than HCV having a 5'UTR similar to HCV-3.

Conclusions

Although HCV-3 replicates in cell types such as B-cells, T-cells, and macrophages, it may require a different primary cell type for the same purpose. Therefore, in our opinion, HCV-3 does not replicate efficiently in macrophages, and patients infected with HCV-3 may contain a population of HCV-1 in their blood.

Occult HCV infection: an unexpected finding in a population unselected for hepatic disease

Background

Occult Hepatitis C virus (HCV) infection is a new pathological entity characterized by presence of liver disease and absence or very low levels of detectable HCV-RNA in serum. Abnormal values of liver enzymes and presence of replicative HCV-RNA in peripheral blood mononuclear cells are also observed. Aim of the study was to evaluate occult HCV occurrence in a population unselected for hepatic disease.

Methodology/Principal Findings

We chose from previous epidemiological studies three series of subjects (n = 276, age range 40–65 years) unselected for hepatic disease. These subjects were tested for the presence of HCV antibodies and HCV-RNA in plasma and in the peripheral blood mononuclear cells (PBMCs) by using commercial systems. All subjects tested negative for HCV antibodies and plasma HCV-RNA and showed normal levels of liver enzymes; 9/276 patients (3.3%) were positive for HCV-RNA in PBMCs, identifying a subset of subjects with potential occult HCV infection. We could determine the HCV type for 8 of the 9 patients finding type 1a (3 patients), type 1b (2 patients), and type 2a (3 patients).

Conclusions

The results of this study show evidence that occult HCV infection may occur in a population unselected for hepatic disease. A potential risk of HCV infection spread by subjects harbouring occult HCV infection should be considered. Design of prospective studies focusing on the frequency of infection in the general population and on the clinical evolution of occult HCV infection will be needed to verify this unexpected finding.

Elevated interleukin-4 expression in severe recurrent hepatitis C virus after liver transplantation

BACKGROUND

Chronic hepatitis C virus (HCV) is usually associated with high levels of hepatic interleukin (IL)-2 and low levels of IL-4 transcripts. HCV frequently recurs after liver transplantation, and its course is accelerated in this setting. We compared in situ expression of IL-2 and IL-4 in transplanted and nontransplanted patients with HCV.

METHODS

A total of 74 liver biopsy specimens were studied; 52 came from transplanted patients, 38 of whom were HCV-positive (17 mild and 21 severe cases of recurrent HCV) and 22 came from nontransplanted patients, 17 of whom were HCV-positive (7 mild and 10 severe cases of HCV). The expression of IL-2 and IL-4 mRNA and IL-4 protein was studied using the reverse transcriptase polymerase chain reaction and immunohistochemical methods, respectively.

RESULTS

IL-2 transcript levels were significantly higher in severe than in mild HCV in both liver graft recipients and nontransplanted patients. However, IL-2 levels were higher in nontransplanted than in transplanted patients. IL-4 transcripts and protein were preferentially detected in graft recipients with severe recurrent HCV.

CONCLUSION

IL-4 expression is elevated in severe recurrent HCV and may play a role in the progression of hepatic lesions after liver transplantation.

Influence of the presence of HCV-RNA in peripheral blood mononuclear cells on the clinical course of chronic hepatitis C in children

The clinical course of chronic hepatitis C (CHC) is generally asymptomatic in children. The aim of this study was to examine the influence of HCV RNA in peripheral blood mononuclear cells (PBMCs) on the clinical course of CHC considering age at the time of infection, length of infection, hepatitis virus C (HCV) genotype, baseline viral load, ALT activity, the degree of liver fibrosis and oncologic history. The study group included forty children, aged 6-18 years with diagnosed CHC. Children were divided into two subgroups: group A (n = 28), with HCV-RNA found in PBMCs and group B (n = 12), with negative results of HCV-RNA in PBMCs. Chosen parameters were analyzed in both study groups according to the aim of the study. Similar age at the time of infection and the length of infection was found in both groups. The majority of the children were infected with genotype 1. Viral load, the stage of fibrosis and ALT activity were comparable in both groups. History of pediatric malignancy concerned the vast majority of children. Presence of HCV-RNA does not seem to influence the clinical course of HCV infection in children.

Replication of hepatitis C virus (HCV) RNA in mouse embryonic fibroblasts: protein kinase R (PKR)-dependent and PKR-independent mechanisms for controlling HCV RNA replication and mediating interferon activities

Hepatitis C virus (HCV) infection causes chronic hepatitis and is currently treated with alpha interferon (IFN-alpha)-based therapies. The underlying mechanisms of chronic HCV infection and IFN-based therapies, however, have not been defined. Protein kinase R (PKR) was implicated in the control of HCV replication and mediation of IFN-induced antiviral response. In this report, we demonstrate that a subgenomic RNA replicon of genotype 2a HCV replicated efficiently in mouse embryonic fibroblasts (MEFs), as determined by cell colony formation efficiency and the detection of HCV proteins and both positive- and negative-strand RNAs. Additionally, the subgenomic HCV RNA was found to replicate more efficiently in the PKR knockout (PKR(-/-)) MEF than in the wild-type (PKR(+/+)) MEF. The knockdown expression of PKR by specific small interfering RNAs significantly enhanced the level of HCV RNA replication, suggesting that PKR is involved in the control of HCV RNA replication. The level of ISG56 (p56) was induced by HCV RNA replication, indicating the activation of PKR-independent antiviral pathways. Furthermore, IFN-alpha/beta inhibited HCV RNA replication in PKR(-/-) MEFs as efficiently as in PKR(+/+) MEFs. These findings demonstrate that PKR-independent antiviral pathways play important roles in controlling HCV replication and mediating IFN-induced antiviral effect. Our findings also provide a foundation for the development of transgenic mouse models of HCV replication and set a stage to further define the roles of cellular genes in the establishment of chronic HCV infection and the mediation of intracellular innate antiviral response by using MEFs derived from diverse gene knockout animals.

Spontaneous viral clearance following acute hepatitis C infection: a systematic review of longitudinal studies

A large number of studies have reported on spontaneous viral clearance rates in acute hepatitis C infection, however most have been small, and reported rates have varied quite widely. To improve the precision of the estimated rate of spontaneous viral clearance, a systematic review was conducted of longitudinal studies. Factors associated with viral clearance were also examined. Inclusion criteria for studies were: longitudinal assessment from time of acute hepatitis C; hepatitis C virus RNA analysis as determinant of viral clearance; untreated for acute hepatitis C. Information on study population, and factors that may influence viral clearance were extracted from each study. Viral clearance was defined among individuals with at least 6 months follow-up following acute hepatitis C. The number of subjects with viral clearance was expressed as a proportion for each study and a weighted mean for proportion was calculated. A total of 31 studies were examined. Study populations included nine studies of post-transfusion hepatitis, 19 of acute clinical hepatitis, and three of sero-incident cases. In total, data was available for 675 subjects and the mean study population was 22 (range 4-67). The proportion with viral clearance ranged from 0.0 to 0.8, with a weighted mean of 0.26 (95% CI 0.22-0.29). Factors associated with viral clearance were female gender and acute clinical hepatitis C study population. Further studies are required to more clearly define predictors of clearance and guide therapeutic intervention strategies.

Undetectable phospho-STAT1 in peripheral blood mononuclear cells from patients with chronic hepatitis C who do not respond to interferon-alpha therapy

BACKGROUND

Recent studies have suggested that phosphorylated signal transducers and activators of transcription 1 (STAT1) plays an important role in interferon (IFN)-mediated biological functions, including antiviral activity. Moreover, it has been demonstrated that suppressors of the cytokine signal 1 (SOCS1) negatively regulates IFN activities.

AIMS

To investigate the involvement of phospho-STAT1 in the response to IFN-alpha therapy in patients with chronic hepatitis C and to evaluate the negative regulatory effect of SOCS1 on STAT1 activation.

METHODS

Sixty-five patients with chronic hepatitis C and 25 healthy subjects were enrolled. Twenty-five of the patients had never been treated with IFN-alpha therapy (naive), while the remaining 40 patients had. The IFN-treated patients were divided into sustained responders (SRs) or non-responders (NRs) on the basis of their response to the antiviral therapy. Peripheral blood mononuclear cells (PBMCs) were obtained from each patient and control, and were either stimulated with IFN-alpha or left unstimulated. Total STAT1, phospho-STAT1 and SOCS1 were revealed by means of Western blot.

RESULTS

Total STAT1 was equally expressed in unstimulated and stimulated PBMCs from all patients and controls. One hundred percent of the stimulated PBMCs from healthy controls and SRs, 96% from naive subjects, and 30% from NRs showed detectable phospho-STAT1. By contrast, 70% of the stimulated PBMCs from NRs showed undetectable phospho-STAT1.

CONCLUSIONS

We have demonstrated that phospho-STAT1 proteins in 70% of patients with chronic hepatitis C who do not respond to IFN treatment are undetectable, which suggests that this protein may be involved in the mediation of IFN sensitivity. The down-regulation of the Jak-STAT pathway because of SOCS1 expression may be one of the possible underlying mechanisms involved in resistance to IFN.

Flow cytometric detection of hepatitis C virus antigens in infected peripheral blood leukocytes: binding and entry

AIM

We designed two synthetic-core-specific peptides core 1 (C1) and core 2 (C2), and an E1-specific peptide (E1). We produced specific polyclonal antibodies against these peptides and used the antibodies for detection of HCV antigens on surface and within infected peripheral blood leukocytes.

METHODS

Peripheral blood from a healthy individual who tested negative for HCV RNA was incubated with HCV type 4 infected serum for 1 h and 24 h at 37 degrees C. Cells were stained by direct and indirect immunofluorescence and measured by flow cytometry.

RESULTS

After 1 h of incubation, antibodies against C1, C2, and E1 detected HCV antigens on the surface of 27%, 26% and 73% of monocytes respectively, while 10%, 5% and 9% of lymphocytes were positive with anti-C1, anti-C2 and anti-E1 respectively. Only 1-3% of granulocytes showed positive staining with anti-C1, anti-C2 and anti E1 antibodies. After 24 h of incubation, we found no surface staining with anti-C1, anti-C2 or anti-E1. Direct immunostaining using anti-C2 could not detect intracellular HCV antigens, after 1 h of incubation with the virus, while after 24 h of incubation, 28% of infected cells showed positive staining. Only plus strand RNA was detectable intracellularly as early as 1 h after incubation, and remained detectable throughout 48 h post-infection. Interestingly, minus RNA strand could not be detected after 1 h, but became strongly detectable intracellularly after 24 h post-infection.

CONCLUSION

Monocytes and lymphocytes are the preferred target cells for HCV infection in peripheral blood leukocytes. Our specific anti-core and anti-E1 antibodies are valuable reagents for demonstration of HCV cell cycle. Also, HCV is capable of infecting and replicating in peripheral blood mononuclear cells as confirmed by detection of minus strand HCV RNA as well as intracellular staining of core HCV antigen.

Flow cytometric detection of hepatitis C virus antigens in infected peripheral blood leukocytes: binding and entry

AIM

We designed two synthetic-core-specific peptides core 1 (C1) and core 2 (C2), and an E1-specific peptide (E1). We produced specific polyclonal antibodies against these peptides and used the antibodies for detection of HCV antigens on surface and within infected peripheral blood leukocytes.

METHODS

Peripheral blood from a healthy individual who tested negative for HCV RNA was incubated with HCV type 4 infected serum for 1 h and 24 h at 37 degrees C. Cells were stained by direct and indirect immunofluorescence and measured by flow cytometry.

RESULTS

After 1 h of incubation, antibodies against C1, C2, and E1 detected HCV antigens on the surface of 27%, 26% and 73% of monocytes respectively, while 10%, 5% and 9% of lymphocytes were positive with anti-C1, anti-C2 and anti-E1 respectively. Only 1-3% of granulocytes showed positive staining with anti-C1, anti-C2 and anti E1 antibodies. After 24 h of incubation, we found no surface staining with anti-C1, anti-C2 or anti-E1. Direct immunostaining using anti-C2 could not detect intracellular HCV antigens, after 1 h of incubation with the virus, while after 24 h of incubation, 28% of infected cells showed positive staining. Only plus strand RNA was detectable intracellularly as early as 1 h after incubation, and remained detectable throughout 48 h post-infection. Interestingly, minus RNA strand could not be detected after 1 h, but became strongly detectable intracellularly after 24 h post-infection.

CONCLUSION

Monocytes and lymphocytes are the preferred target cells for HCV infection in peripheral blood leukocytes. Our specific anti-core and anti-E1 antibodies are valuable reagents for demonstration of HCV cell cycle. Also, HCV is capable of infecting and replicating in peripheral blood mononuclear cells as confirmed by detection of minus strand HCV RNA as well as intracellular staining of core HCV antigen.

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Screening of HCTP4 interacting proteins in leukocytes by yeast-two hybrid technique

AIM: To investigate the biological function of HCTP4, yeast-two hybrid was performed to screen proteins interacting with HCTP4 in leukocytes.

METHODS: The HCTP4 gene was amplified by polymerase chain reaction (PCR) and HCTP4 bait plasmid was constructed by using yeast-two hybrid system 3, then the constructed vector was transformed into yeast AH109. The transformed yeast mated with yeast Y187 containing leukocytes cDNA library plasmid in 2×YPDA medium. Diploid yeast was plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing x--gal for selecting two times and screening. After extracting and sequencing of plasmid from blue colonies, we underwent analysis by bioinformatics.

RESULTS: Forty-four colonies were sequenced, among which twenty-five colonies were immunoglobulin lambda light chain, six human DNA sequences from clone RP11-189K21, four human DNA sequences from clone RP11-507C10, two homo sapiens 12p BAC RPCI11-75L1, one homo sapiens BAC clone RP11-21M10, one homo sapiens ubiquitin ligase mind bomb (MIB), one homo sapiens genomic DNA, chromosome 11 clone: RP11-867O8, one human DNA sequence from clone RP3-509I19, one homo sapiens small nuclear ribonucleoprotein polypeptide G, one homo sapiens UMP-CMP kinase (UMP-CMPK), and a new gene.

CONCLUSION: Genes of HCTP4 interacting proteins in leukocytes are successfully cloned and the results bring some new clues for studying the biological functions of HCTP4 and associated proteins.

Effect of in vitro interferon-beta administration on hepatitis C virus in peripheral blood mononuclear cells as a predictive marker of clinical response to interferon treatment for chronic hepatitis C

AIM: To test whether in vitro incubation of peripheral blood mononuclear cells (PBMC) with interferon (IFN) could efficiently decrease hepatitis C virus-RNA (HCV-RNA) amount and to analyze whether this effect was associated with clinical response to IFN.

METHODS: Twenty-seven patients with histologically proven chronic hepatitis C were given intravenous administration of 6 million units (MU) IFN-β daily for 6 weeks followed by three times weekly for 20 weeks. PBMC collected before IFN therapy were incubated with IFN-β and HCV-RNA in PMBC was semi-quantitatively determined.

RESULTS: Twenty-five patients completed IFN therapy. Eight patients (32%) had sustained loss of serum HCV-RNA with normal serum ALT levels after IFN therapy (complete responders). HCV-RNA in PBMC was detected in all patients, whereas it was not detected in PBMC from healthy subjects. In vitro administration of IFN-β decreased the amount of HCV-RNA in PMBC in 18 patients (72%). Eight of these patients obtained complete response. On the other hand, none of the patients whose HCV-RNA in PBMC did not decrease by IFN-β was complete responders. Multiple logistic regression analysis revealed that the decrease of HCV-RNA amount in PBMC by IFN-β was the only independent predictor for complete response (P < 0.05).

CONCLUSION: The effect of in vitro IFN-β on HCV in PBMC reflects clinical response and would be taken into account as a predictive marker of IFN therapy for chronic hepatitis C.

Cytopathic and noncytopathic interferon responses in cells expressing hepatitis C virus subgenomic replicons

Hepatitis C virus (HCV) is the only known positive-stranded RNA virus that causes persistent lifelong infections in humans. Accumulation of HCV RNA can be inhibited with alpha interferon (IFN-alpha) in vivo and in culture cells. We used cell-based assay systems to investigate the mechanisms responsible for the cytokine-induced inhibition of HCV replication. The results showed that IFN-alpha could suppress the accumulation of viral RNA by a noncytopathic pathway and could also induce apoptosis of virally infected cells in a concentration- and cell line-dependent fashion. Whereas the noncytopathic IFN-alpha response depended on a functional Jak-STAT signal transduction pathway, it did not appear to require double-stranded RNA-dependent pathways. Moreover, we found that functional proteasomes were required for establishment of the IFN-alpha response against HCV. Based on the results described in this study we propose a model for the mechanism by which IFN-alpha therapy suppresses HCV replication in chronic infections by both cytopathic and noncytopathic means.

Replication of hepatitis C virus subgenomes in nonhepatic epithelial and mouse hepatoma cells

The hepatitis C virus (HCV) pandemic affects the health of more than 170 million people and is the major indication for orthotopic liver transplantations. Although the human liver is the primary site for HCV replication, it is not known whether extrahepatic tissues are also infected by the virus and whether nonprimate cells are permissive for RNA replication. Because HCV exists as a quasispecies, it is conceivable that a viral population may include variants that can replicate in different cell types and in other species. We have tested this hypothesis and found that subgenomic HCV RNAs can replicate in mouse hepatoma and nonhepatic human epithelial cells. Replicons isolated from these cell lines carry new mutations that could be involved in the control of tropism of the virus. Our results demonstrated that translation and RNA-directed RNA replication of HCV do not depend on hepatocyte or primate-specific factors. Moreover, our results could open the path for the development of animal models for HCV infection.

HCV replication in PBMC and its influence on interferon therapy

AIM: To study hepatic virus C (HCV) RNA and HCV protein expression in peripheral blood mononuclear cells (PBMCs) of patients with HCV infection, and explore the relationship between the HCV RNA in the PBMCs and response to interferon (IFN) therapy.

METHODS: Type-specific primers were designed and RT-nested PCR was used to detect the plus- and minus- strands of HCV RNA in PBMCs of 54 patients with HCV infection; Indirect immunofluorescence assay was applied to identify HCVNS5 protein expression in PBMCs; 6 month-, 3 MU-IFN regiment was administrated to observe the responses to IFN in 35 chronic hepatitis C patients with different HCV RNA status in PBMCs.

RESULTS: HCV plus strand RNA was found in 10 of 19 (52.6%) acute hepatitis C patients and 22 of 35 (62.9%) chronic hepatitis C patients. HCV minus strand RNA was detected in 14 of 35 (40.0%) chronic hepatitis C patients, but only one patient (5.3%) with acute HCV infection was found to be minus HCV RNA positive. Though no HCV NS5 protein expression was found in the examined 10 cases of acute HCV infection, it was positive in 17 of 20 (85.0%) chronic hepatitis C patients by indirect immunofluoresence assay. There are significant differences of positive rate of the minus-strand and HCVNS5 protein between acute and chronic hepatitis C groups (u = 2.07, P < 0.05 and u = 4.43, P < 0.01 respectively). The patients with minus-strand HCV RNA showed a significantly lower 6-month sustained response (SR-6) to IFN compared to those without minus-strand HCVRNA in PBMCs (biologically 14.3% vs 42.8%, χ² = 4.12, P < 0.05 and virologically 7.1% vs 23.9%, χ² = 4.24, P < 0.05).

CONCLUSION: HCV is capable of infecting and replicating in PBMCs, and HCVNS5 protein was expressed in PBMCs. The patients with minus strand HCV RNA in PBMCs showed a significantly lower 6-month sustained response to IFN, suggesting that minus-strand HCV RNA in PBMCs may be one of the factors influencing response to IFN therapy.

Clinical comparison of high-dose interferon-alpha2b with or without ribavirin for treatment of interferon-relapsed chronic hepatitis C

BACKGROUND

Interferon a with ribavirin combination therapy is effective but still unsatisfactory in the treatment of patients with interferon-relapsed chronic hepatitis C.

AIMS

To compare, in a randomized, double blind, placebo-controlled study, high-dose interferon-alpha2b with or without ribavirin in the treatment for interferon-relapsers.

PATIENTS

A total of 52 patients with interferon-relapsed chronic hepatitis C were randomly assigned to receive 24-week treatment with interferon-alpha2b (6 MU three times per week) combined with either ribavirin (1,000 to 1,200 mg per day) or a matched placebo and then followed for an additional 24 weeks.

METHODS

Hepatitis C virus RNA was detected by reverse-transcription polymerase chain reaction. For determining viral concentration, the commercial bDNA Quantiplex hepatitis C virus-RNA 2.0 assay was used. Genotyping was performed by reverse hybridization assay

RESULTS

At the end of treatment, no detectable hepatitis C virus RNA levels were observed in 92% (24/26) of patients on interferon alpha2b/ribavirin and 81% (21/26) of patients on interferon alpha2b/placebo. At the end of the follow-up, a higher sustained virological response rate was seen in patients treated with interferon alpha2b/ribavirin than those treated with interferon alpha2b/placebo (69% vs 23%, p < 0.001). Patients with either initially high levels of viral concentration or with genotype 1 responded poorly. Patients who received interferon-alpha2b/ribavirin treatment and in whom no hepatitis C virus RNA was detected at 4th week after treatment had 90% chance to achieve sustained virological response.

CONCLUSIONS

High-dose interferon-alpha2b plus ribavirin treatment is highly effective in interferon-relapsed patients.

Hepatitis C virus core protein leads to immune suppression and liver damage in a transgenic murine model

Hepatitis C virus (HCV) is remarkably efficient in establishing persistent infection, possibly mediated by an impaired immune response to HCV infection. There is compelling evidence that HCV can infect immune cells, such as macrophages, B cells, and T cells. It has been previously reported that HCV core, the first protein expressed during the early phase of viral infection, contains the immunomodulatory function of suppressing host immune responses. This altered function of immune cells caused by HCV infection may explain the ineffective immune response to HCV. To further characterize the immunomodulatory role of HCV core in vivo, we generated transgenic (TG) mice by directing the expression of core protein to T lymphocytes by using the CD2 promoter. T-lymphocyte responses, including the production of gamma interferon and interleukin-2, were significantly diminished in these mice compared to their non-TG littermates. The inhibition of T-lymphocyte responsiveness may be due to the increased susceptibility of peripheral T lymphocytes to Fas-mediated apoptosis. Surprisingly, significant lymphocyte infiltration was observed in the portal tracts of livers isolated from core TG mice, associated with increasing serum alanine aminotransferase levels. Moreover, no intrahepatic lymphocytes or liver damage was found in non-TG littermates and core TG mice bred to Fas-deficient lpr mice. These results suggest that HCV core drives liver injury by increasing Fas-mediated apoptosis and liver infiltration of peripheral T cells.

Vaginal shedding of hepatitis C virus

A group of 14 women infected with hepatitis C virus (HCV) was evaluated for vaginal shedding of the virus. The HCV-RNA detection was performed in plasma, peripheral blood mononuclear cells (PBMC) and in supernatant and pellet of vaginal washings. HCV-RNA positive results were obtained in all plasma samples, in 57% of the PBMC samples, in 36% pellets obtained following centrifugation of vaginal washings and in 36% of the supernatants. In 21% of the women a positive result was found, at the same time, in every analysed product. The HCV genotypes identified in the plasma samples (1a: 38%; 1b: 36%; 3a: 13% and 1b+3a: 14%) matched with those in PBMC and vaginal washings in every sample, with the exception of cases where mixed infection (1b+3a) was detected. In these, genotype 1b was only detected in plasma. HCV viral load was not associated with the presence of HCV-RNA in PBMC or in vaginal washings (either cells or supernatant).

Treatment of patients with chronic hepatitis C not responding to interferon with high-dose interferon alpha with or without ribavirin: final results of a prospective randomized trial. Austrian Hepatitis Study Group

OBJECTIVE

To investigate the efficacy of high-dose interferon alpha (IFN-alpha) with or without ribavirin in interferon (IFN) non-responders.

STUDY DESIGN

304 chronic hepatitis C patients received 5 MU IFN-alpha2b (IntronA, Schering-Plough, Kenilworth, NJ, USA) three times a week for 3 months. Non-responders were randomized either to continue with IFN (IFN 5 MU/TIW followed by 10 MU/TIW, each for 3 months) alone (group A: n = 76, m: f = 54: 22, age 45.7 +/- 12 years, 16% cirrhosis, alanine aminotransferase [ALT] 66 +/- 35 U/l) or in combination with ribavirin (approximately 14 mg/kg/day) (group B: n = 81, m: f = 57: 24, age 48.2 +/- 12 years, 17% cirrhosis, ALT 71 +/- 40 U/l). At the end of treatment, patients were followed for 6 months.

MAIN OUTCOME MEASURES

Virological response at end of treatment and 6 months thereafter.

SETTING

University hospitals and tertiary referral centres.

RESULTS

At the end of treatment, eight (10.8%) and 25 (31.3%, P= 0.0066) patients were HCV-RNA negative, and 51 and 39 were HCV-RNA positive, in groups A and B, respectively. There were 17 drop-outs in each group. Six months after treatment, only one patient in group A (1.3%) and seven patients (8.6%, P= 0.06) in group B had normal ALT and undetectable serum HCV-RNA.

CONCLUSIONS

A combination of high-dose IFN with ribavirin induces a short-lasting complete response in about one-third of IFN-non-responders.

The clinic study on synchronous detection of HCV RNA in the plasma and PBMC of hepatitis C patients

In order to increase the positive detection rate of HCV RNA in the patients with chronic hepatitis C (CHC), RT-PCR was used to synchronously detect HCV RNA in the plasma and peripheral blood mononuclear cells (PBMC) of 583 CHC patients with a continuously elevated level of ALT for more than one year. The results showed that the positive detection rate of HCV RNA in the plasma of the CHC patients was 19.2%, while 24.5% in PBMC. It was demonstrated that the positive detection rate for HCV RNA in PBMC was obviously higher than that detected in plasma. To synchronously detect HCV RNA in PBMC by using RT-PCR can increase the positive detection rate of HCV RNA in the CHC patients.

Hepatitis C virus and interferon resistance

Interferon plays a critical role in the host's natural defense against viral infections and in their treatment. It is the only therapy for hepatitis C virus (HCV) infection; however, many virus isolates are resistant. Several HCV proteins have been shown to possess properties that enable the virus to evade the interferon-mediated cellular antiviral responses.

Cell type-specific enhancement of hepatitis C virus internal ribosome entry site-directed translation due to 5' nontranslated region substitutions selected during passage of virus in lymphoblastoid cells

Low-level replication of hepatitis C virus (HCV) in cultured lymphoblastoid cells inoculated with H77 serum inoculum led to the appearance of new virus variants containing identical substitutions at three sites within the viral 5' nontranslated RNA (5'NTR): G(107)-->A, C(204)-->A, and G(243)-->A (N. Nakajima, M. Hijikata, H. Yoshikura, and Y. K. Shimizu, J. Virol. 70:3325-3329, 1996). These results suggest that virus with this 5'NTR sequence may have a greater capacity for replication in such cells, possibly due to more efficient cap-independent translation, since these nucleotide substitutions reside within the viral internal ribosome entry site (IRES). To test this hypothesis, we examined the translation of dicistronic RNAs containing upstream and downstream reporter sequences (Renilla and firefly luciferases, respectively) separated by IRES sequences containing different combinations of these substitutions. The activity of the IRES was assessed by determining the relative firefly and Renilla luciferase activities expressed in transfected cells. Compared with the IRES present in the dominant H77 quasispecies, an IRES containing all three nucleotide substitutions had significantly greater translational activity in three of five human lymphoblastoid cell lines (Raji, Bjab, and Molt4 but not Jurkat or HPBMa10-2 cells). In contrast, these substitutions did not enhance IRES activity in cell lines derived from monocytes or granulocytes (HL-60, KG-1, or THP-1) or hepatocytes (Huh-7) or in cell-free translation assays carried out with rabbit reticulocyte lysates. Each of the three substitutions was required for maximally increased translational activity in the lymphoblastoid cells. The 2- to 2.5-fold increase in translation observed with the modified IRES sequence may facilitate the replication of HCV, possibly accounting for differences in quasispecies variants recovered from liver tissue and peripheral blood mononuclear cells of the same patient.

Early detection of hepatitis C allograft reinfection after orthotopic liver transplantation: a molecular and histologic study

After orthotopic liver transplantation (OLT), patients with chronic hepatitis C virus (HCV) infection show nearly universal persistence of viremia and reinfection of the liver, but identifying the point at which the liver is reinfected morphologically can be difficult. One tool that may potentially be useful to detect reinfection is reverse transcriptase-polymerase chain reaction (RT-PCR), which has proven to be highly sensitive for detecting HCV RNA in formalin-fixed paraffin-embedded liver tissue. Our purpose was to gain insight into the time frame of HCV reinfection by assaying for HCV RNA in serial posttransplant liver biopsy specimens. Our study population consisted of 14 patients who underwent liver transplantation for hepatitis C and had confirmed HCV RNA in pretransplant serum, absence of HCV RNA in donor livers, and available consecutive posttransplant liver allograft specimens. We performed RT-PCR for HCV RNA in serial posttransplant liver biopsy specimens, beginning at 1 week until at least one biopsy from each tested positive. HCV RNA was detected in liver tissue by RT-PCR in 1-week post-OLT liver samples in 6 of 14 (42.8%) patients, the earliest being 5 days post-OLT. Eventually, each of the remaining eight samples became RT-PCR positive as well; the first detections occurred in these at 3 weeks (three cases), 4 weeks (three cases), 48 weeks (one case), and 144 weeks (one case). Histologic identification of hepatitis C recurrence was relatively insensitive in relation to these molecular data. These data suggest that (1) HCV RNA reinfection is nearly universal after liver transplantation in patients with chronic hepatitis C infection, (2) molecular reinfection by HCV occurs at a variable interval post-OLT, with the majority of allograft livers reinfected as early as 1 week, and (3) morphologic features of hepatitis C are usually appreciable at the time of "molecular" recurrence.

Nucleotide and amino acid complexity of hepatitis C virus quasispecies in serum and liver

The quasispecies nature of the hepatitis C virus (HCV) is thought to play a central role in maintaining and modulating viral replication. Several studies have tried to unravel, through the parameters that characterize HCV circulating quasispecies, prognostic markers of the disease. In a previous work we demonstrated that the parameters of circulating viral quasispecies do not always reflect those of the intrahepatic virus. Here, we have analyzed paired serum and liver quasispecies from 39 genotype 1b-infected patients with different degrees of liver damage, ranging from minimal changes to cirrhosis. Viral level was quantified by real-time reverse transcription-PCR, and viral heterogeneity was characterized through the cloning and sequencing of 540 HCV variants of a genomic fragment encompassing the E2-NS2 junction. Although in 95% of patients, serum and liver consensus HCV amino acid sequences were identical, quasispecies complexity varied considerably between the viruses isolated from each compartment. Patients with HCV quasispecies in serum more complex (26%) than, less complex (28%) than, or similarly complex (41%) to those in liver were found. Among the last, a significant correlation between fibrosis and all the parameters that measure the viral amino acid complexity was found. Correlation between fibrosis and serum viral load was found as well (R = 0.7). With regard to the origin of the differences in quasispecies complexity between serum and liver populations, sequence analysis argued against extrahepatic replication as a quantitatively important contributing factor and supported the idea of a differential effect or different selective forces on the virus depending on whether it is circulating in serum or replicating in the liver.

Interim analysis of a randomized controlled trial of combination of ribavirin and high dose interferon-alpha in interferon nonresponders with chronic hepatitis C

This trial investigated the efficacy of a combination of high-dose interferon-alpha (IFN-alpha) with ribavirin in IFN nonresponders.

STUDY PROTOCOL

304 patients with chronic hepatitis C were treated with 5 MU IFN-alpha2b (IntronA(R), Schering-Plough) per TIW for 3 months. Nonresponders (defined by HCV-RNA positivity in serum after the 3 months of therapy) were randomized either to continue with IFN (5 MU IFN per TIW followed by 10 MU per TIW for each 3 months) alone (group A) or in combination with ribavirin (1-1.2 g per day) (group B). ALT was measured in monthly intervals, HCV-RNA in 3 monthly intervals. Pretreatment characteristics of the randomized patients were as follows: group A, n = 76; m/f, 54/22; 16% cirrhosis, age, 45. 7 +/- 12 years; ALT (U per litre), 66 +/- 35; group B, n = 81; m/f, 57/24; 17% cirrhosis, age, 48.2 +/- 12; ALT, 71 +/- 40. After 9 months of treatment, nine (11.6%) and 27 (32.5%, P = 0.0066) patients were HCV-RNA negative and 51 and 39 were HCV-RNA positive, in groups A and B, respectively. There were 17 drop-outs in group A and 15 in group B. Six months after treatment only two patients in group A (2.5%) and five (6%, P = 0.06) in group B had normal ALT and no detectable HCV-RNA in serum. In addition to the well-known side-effects of IFN the mean haemoglobin concentration dropped by 2 g per litre in group B. These data indicate that a combination of high-dose IFN with ribavirin is effective in inducing a short-lasting complete response in one-third of IFN nonresponders. Prolonged treatment with IFN/ribavirin may be necessary to obtain a sustained response.

Persistence of viremia and the importance of long-term follow-up after acute hepatitis C infection

The purpose of this investigation was to prospectively characterize acute hepatitis C virus (HCV) infections and to evaluate the hypothesis that the outcome is affected by identifiable clinical or viral factors. One hundred forty-two people with a history of illicit drug use who were HCV antibody-negative in 1988 were followed semiannually through 1996. HCV seroconversion (second generation enzyme immunoassay and recombinant immunoblot assay) was recognized in 43 (30%) of the participants, who were followed up for a median of 72 months. HCV RNA was detected and quantified by polymerase chain reaction in a median of 10 specimens per participant and showed two distinct patterns of viremia: viral clearance was noted in 6 (14%) of the participants, and viral persistence was observed in 37 (86%) of the participants. Subjects with viral clearance were more likely to be white (P =.004), have jaundice (P =.03), and have lower peak viral titer (P =.003). However, the outcome for a given person could not be predicted by clinical features, RNA level, or HCV subtype (as ascertained by analysis of core-E1 complementary DNA sequence). No acute infections were recognized by health care providers. At the time of seroconversion, HCV RNA was detectable in 81% of participants, and recombinant immunoblot assay (RIBA) was positive in 85% of participants. We conclude that approximately 85% of people with acute hepatitis C develop persistent viremia. However, acute infections are uncommonly recognized clinically, underscoring the importance of screening individuals at risk. Long-term follow-up, but no single laboratory test, is necessary to ascertain the outcome and in some cases make the diagnosis of acute HCV infection.

Detection of GB virus-C/hepatitis G virus genome in peripheral blood mononuclear cells and liver tissue

The replication site for the GB virus-C/hepatitis G virus (GBV-C/HGV) was investigated by using polymerase chain reaction (PCR)-based assays and in situ hybridisation. A total of 28 patients with consecutive GBV-C/HGV infection were enrolled in this study: Nine patients were being treated with immunosuppressive therapy after liver transplantation, and the remaining 19 patients were not receiving such treatment. GBV-C/HGV RNA was detected by using reverse transcriptase-polymerase chain reaction (RT-PCR) and was quantitated by using competitive RT-PCR in all patients. Positive and negative strands of GBV-C/HGV RNA in liver tissue were detected with in situ hybridisation by using RNA probes that were specific for the GBV-C/HGV genome. Concentrations of GBV-C/HGV RNA in serum were significantly higher (P=0.003) in the nine patients who were receiving immunosuppression (median, 10(7) copy/ml; range, 10(5)-10(7)) than in the 19 patients who were not receiving immunosuppressive therapy (median, 10(4) copy/ml; range, 10(2)-10(7)). In situ hybridisation of GBV-C/ HGV RNA was performed on paraffin-embedded liver tissue that was obtained from six patients with GBV-C/HGV infection. Two of those six patients were receiving immunosuppressive therapy, and four were not. Significant positive signals were observed in the samples from two of the six patients who were infected with GBV-C/HGV, but such signals were not observed in any of the six patients who were without the infection. The two patients with positive signals (both were undergoing immunosuppressive therapy) showed both positive and negative strands of GBV-C/HGV RNA in mononuclear cells that infiltrated into portal areas, but neither of the strands was observed in hepatocytes. Moreover, the GBV-C/HGV replication was analysed in peripheral blood mononuclear cells by using strand-specific PCR (conventional RT-PCR and rTth method). Two of the six patients were positive for negative-strand GBV-C/HGV RNA by using conventional RT-PCR. In conclusion, GBV-C/HGV replication was active under an immunosuppressive state, and it is suggested that GBV-C/HGV replicates in mononuclear cells.

Hepatitis C virus infection, mixed cryoglobulinemia, and non-Hodgkin's lymphoma: an emerging picture

Hepatitis C virus (HCV) is a single-stranded RNA agent which expresses its genetic informations in the form of a single, large polyprotein encoded by an open reading frame (ORF) that extends through most of its genomic RNA. Proteolytic cleavage of the ORF product is essential for the virogenesis and the production of viral progeny. HCV is responsible for chronic liver disease, cirrhosis and possibly hepatocellular carcinoma. Viral persistence is considered the greatest problem in the management of HCV infection. It may result from several mechanisms, two of which are established. In the first, the high rate of genetic variations during viral replication results in the production of mutants capable of escaping the immune attack. In the second, the virus infects cells of the immune system itself, which represent a privileged site that cannot be reached by virus-specific T cell response. Involvement of lymphoid cells in the early stages of HCV infection may provide insight into the pathobiologic patterns of extrahepatic dissemination (lymph nodes, major salivary glands, kidneys, blood vessels). Dissemination of HCV-infected lymphoid cells throughout the organism is likely to maintain a mobile and extensive reservoir of the virus. In this respect, extrahepatic sites may act as a source of continuous reinfection of hepatocytes. Studies of intrahepatic B lymphocytes indicate that they are infected with HCV, clonally expanded and activated to secrete IgM molecules with rheumatoid factor activity. This strongly suggests that HCV directly stimulates B cell expansion, which may result in an indolent stage of lymphoproliferation (i.e., mixed cryoglobulinemia) or in frank B cell non-Hodgkin's lymphoma (NHL). The frequency of NHL, however, is much lower than that of HCV infection, suggesting that HCV alone is not able to induce tumors and that cellular events, in addition to the presence of virus and virus-encoded products, are necessary in order to obtain a malignant B cell phenotype. The demonstration of HCV productive infection in bone marrow-recruited and circulating pluripotent hematopoietic CD34+ stem cells indicates that HCV replication occurs in the early differentiation stages of hematopoietic progenitors. These are stable cell populations and are likely to represent the initial site of infection and a continuous source of virus production.

mRNA cytokine profile in peripheral blood cells from chronic hepatitis C virus (HCV)-infected patients: effects of interferon-alpha (IFN-alpha) treatment

Natural immune responses, both cellular and humoral, are not capable of terminating HCV infection in most patients. A role has been suggested for peripheral blood leucocytes (PBL) in viral persistence and clinical implications, as these cells may serve as a viral reservoir and at the same time may be inadequate active participants in antiviral immune reactions. IFN-alpha administration, although only partially successful, is currently the main therapy available for chronic HCV patients. In addition to its antiviral effects, IFN-alpha regulates the function of cytokines, their receptors and other molecules of immune importance. The aim of this study was to determine cytokine mRNA expression in PBL derived from chronic HCV patients prior to and at termination of IFN-alpha treatment. HCV RNA was still observed in sera of most patients (10 out of 14 treated patients) at termination of treatment. In pretreated patients mRNA expression of Th2 (IL-4, IL-6 and IL-10) and Th3 (transforming growth factor-beta (TGF-beta)) was observed in only a low percentage of PBL samples from patients, similar to controls. IFN-alpha treatment led to an elevation in the number of samples expressing these cytokines (significant for IL-4, IL-6, IL-10, tumour necrosis factor-alpha (TNF-alpha) and TGF-beta), accompanied by reduction in liver enzymes but in serum viral load in only approximately 30% of patients. Expression of TNF-alpha and TNF-beta mRNA was observed in samples from patients but not controls, while no differences were observed for mRNA of classical Th1 cytokines (IL-2 and IFN-gamma) between patients before or during treatment as well as controls. The cytokine mRNA profile following IFN-alpha treatment points to an anti-inflammatory response which does not appear to be involved in termination of the viral infection. The PBL cytokine profile observed in this study may explain the failure of the immune system to eradicate HCV chronic infection and suggests that early treatment in the acute phase of disease with agents that stimulate cytotoxic immune type 1 responses may lead to eradication of HCV infection.

Quantitative assessment of hepatitis C virus RNA in peripheral blood mononuclear cells during therapy with interferon-alpha2a

A significant number of patients with hepatitis C (HCV) treated with interferon (IFN) will initially clear their serum of HCV RNA, but will then have recurrence of viraemia either during or after therapy. One proposed mechanism for relapse is that HCV may persist in peripheral blood mononuclear cells (PBMCs) and that the PBMCs serve as a 'viral reservoir' that is resistant to IFN. To address this hypothesis, we performed serial, quantitative polymerase chain reaction (PCR) of HCV RNA in serum and PBMCs from 26 consecutive patients treated with IFN-alpha2a. Of the 26 patients, 11 (42%) did not clear virus from their serum during therapy and were termed non-responders. Five patients (19%) had sustained clearance of virus from serum and were termed complete responders. The remaining 10 patients (39%) initially eliminated HCV RNA from their serum, but had relapse of viraemia. They were termed partial responders. In all 10 partial responders HCV RNA was undetectable in PBMCs at the same time that it was undetectable in serum. When virus recurred in serum, it was preceded by or occurred at the same time as the return of virus in PBMCs. The results of our study indicate that PBMCs did not serve as an IFN-resistant 'viral reservoir' during therapy. Partial responders who transiently cleared virus from serum also cleared virus from PBMCs and the presence or titre of HCV RNA in PBMCs at the initiation of therapy did not predict response to therapy.

Chronic hepatitis C: T-helper1/T-helper2 imbalance could cause virus persistence in peripheral blood

Interferon gamma (IFN gamma) and interleukin 4, 10 and 12 (IL-4, -10, -12) production was measured in whole peripheral blood (WPB) and peripheral blood mononuclear cells (PBMC) of 10 chronic hepatitis C (CHC) patients. The level of IFN gamma in supernatants in mitogen-activated WPB was lower than in healthy donors. IL-10 served as a possible downregulative factor for IFN gamma, since its spontaneous IL-10 production was enhanced in CHC. Neutralization of IL-10 partly restored IFN gamma response in CHC patients. Recombinant IL-12 (rIL-12) also enhanced IFN gamma of CHC patients, but IL-12 production was decreased in CHC. Thus, IFN gamma production deficiency in CHC patients is secondary to blockage by high levels of IL-10-impaired IL-12 production.

Detection of hepatitis C virus genomic sequences in the cerebrospinal fluid of HIV-infected patients

To assess the presence of hepatitis C virus (HCV) in the central nervous system (CNS), HCV-RNA was sought in paired serum and cerebrospinal fluid (CSF) samples of 21 HIV/HCV-positive patients: HCV-RNA was detected in the serum of 19/21 patients (90.4%), and in the CSF of five of the 19 serum-positive patients. The presence of HCV-RNA was confirmed in follow-up CSF samples available for three of these five patients. An identical HCV genotype was found in the paired serum/CSF samples. No correlation was found between the different genotypes and the presence of HCV in CSF of the individual patients. HCV viremia levels measured by branched-DNA and quantitative PCR were not significantly higher in the CSF-positive cases than in the CSF-negative cases (P = 0.3, using b-DNA; 0.5, using quantitative PCR). This report shows the presence of HCV in CSF and raises the possibility that the CNS may act as a reservoir site for HCV.

Effects of formalin fixation and prolonged block storage on detection of hepatitis C virus RNA in liver tissue

It has been suggested that prolonged formalin fixation and block storage adversely affect hepatitis C virus (HCV) ribonucleic acid (RNA) detection in tissue by reverse transcriptase-polymerase chain reaction (RT-PCR). We attempted to determine whether short-term perfusion fixation (3-5 days) or prolonged formalin storage adversely affects the detection of HCV RNA in paraffin-embedded tissue in comparison with 24-h fixation. Also, we examined the effects of prolonged storage of paraffin blocks on the sensitivity for HCV detection. We performed RT-PCR in formalin-fixed explanted livers from 20 liver allograft recipients known to be HCV positive (10 with specimens stored for 2-4 years and 10 with specimens stored for > 4 years). We compared the results of perioperative needle liver biopsy specimens fixed overnight with liver sections fixed by perfusion for 3-5 days and bulk liver tissue stored in formalin for years (mean, 6.25 years; range, 2-11 years). HCV RNA was detected in 100%, 85%, and 0% of specimens fixed for 24 h, 3-4 days, and years, respectively. We conclude that HCV can be readily detected in tissue fixed by formalin overnight, sensitivity decreases slightly with intermediate-length fixation, and HCV is rendered undetectable by prolonged fixation. In addition, retention of formalin-fixed tissue in paraffin blocks does not affect the sensitivity of HCV detection.

Virus elimination and histologic improvement in patients with chronic hepatitis C treated with interferon alpha

We evaluated the elimination of hepatitis C virus (HCV) by means of interferon alpha (IFN-alpha) by investigating both positive- and negative-stranded RNA forms in the peripheral blood mononuclear cells and liver tissue. We also assessed the long-term histologic improvement accompanying viral clearance. We studied 20 persons with HCV whose serum aminotransferase levels remained normal for more than 1.5 years after IFN-alpha treatment withdrawal. The presence of HCV RNA in their peripheral blood and of both positive and negative strands in the peripheral blood mononuclear cells and liver tissue was investigated using the reverse transcription polymerase chain reaction method. We examined the histologic findings using the European classification and the histology activity index scoring system. In 16 of 20 patients, both strands disappeared from the possible reservoirs. The histologic findings indicated reduced activity, and histology activity index scores (1, 2, 3, and total) also showed significant improvement. We confirmed that IFN-alpha therapy can induce the elimination of HCV RNA from the conceivable HCV reservoirs and effect histologic improvement. Therapy with IFN-alpha is effective for treating chronic hepatitis C.