The burden of hepatitis C in the United States

The epidemiology of hepatitis C infection in the United States

BACKGROUND

The prevalence of hepatitis C virus (HCV) infection in the United States has remained constant from 1988 through 2002, although the peak age of infection has increased. While the number of new HCV cases is declining, the rates of HCV-associated morbidity and mortality are increasing. We reviewed the risk factors for HCV infection, the laboratory methods used to diagnose it, the dynamics of disease progression, and the natural history of HCV infection.

METHODS

Medline searches were performed using the key word HCV, together with incidence, risk factors, demographics, diagnostic methods, disease progression, natural history, normal alanine aminotransferase (ALT), fibrosis, and hepatocellular carcinoma (HCC).

RESULTS

Three characteristics-abnormal serum ALT, history of injection drug use, and blood transfusion before 1992-identified 85% of HCV-positive individuals 20-59 years old. About 75%-85% of acutely infected individuals progress to chronic infection, with up to 20% developing liver cirrhosis over 20-25 years, putting them at increased risk for end-stage liver disease and/or HCC. HCV-associated cirrhosis is the leading cause of liver transplantation in the United States. Rates of infection are higher in non-Hispanic blacks than in non-Hispanic whites and Mexican Americans and higher in men than in women. In the United States, over 70% of HCV-infected individuals are infected with genotype 1.

CONCLUSIONS

HCV infection is more prevalent than human immunodeficiency virus or hepatitis B virus infection and is particularly common among certain demographic groups. Individual rates of fibrosis progression vary, but identification of host and viral characteristics associated with disease progression may reveal the mechanisms of HCV-associated hepatic fibrosis/cirrhosis.

Comparison of performance characteristics of three real-time reverse transcription-PCR test systems for detection and quantification of hepatitis C virus

We evaluated the performance characteristics of three real-time reverse transcription-PCR test systems for detection and quantification of hepatitis C virus (HCV) and performed a direct comparison of the systems on the same clinical specimens. Commercial HCV panels (genotype 1b) were used to evaluate linear range, sensitivity, and precision. The Roche COBAS TaqMan HCV test for research use only (RUO) with samples processed on the MagNA Pure LC instrument (Roche RUO-MPLC) and Abbott analyte-specific reagents (ASR) with QIAGEN sample processing (Abbott ASR-Q) showed a sensitivity of 1.0 log(10) IU/ml with a linear dynamic range of 1.0 to 7.0 log(10) IU/ml. The Roche ASR in combination with the High Pure system (Roche ASR-HP) showed a sensitivity of 1.4 log(10) IU/ml with a linear dynamic range of 2.0 to 7.0 log(10) IU/ml. All of the systems showed acceptable reproducibility, the Abbott ASR-Q being the most reproducible of the three systems. Seventy-six clinical specimens (50 with detectable levels of HCV RNA and various titers and genotypes) were tested, and results were compared to those of the COBAS Amplicor HCV Monitor v2.0. Good correlation was obtained for the Roche RUO-MPLC and Abbott ASR-Q (R(2) = 0.84 and R(2) = 0.93, respectively), with better agreement for the Abbott ASR-Q. However, correlation (R(2) = 0.79) and agreement were poor for Roche ASR-HP, with bias relative to concentration and genotype. Roche ASR-HP underestimated HCV RNA for genotypes 3 and 4 as much as 2.19 log(10) IU/ml. Our study demonstrates that Roche RUO-MPLC and Abbott ASR-Q provided acceptable results and agreed sufficiently with the COBAS Amplicor HCV Monitor v2.0.

Structure-function relationships of the viral RNA-dependent RNA polymerase: fidelity, replication speed, and initiation mechanism determined by a residue in the ribose-binding pocket

Studies of the RNA-dependent RNA polymerase (RdRp) from poliovirus (PV), 3Dpol, have shown that Asn-297 permits this enzyme to distinguish ribose from 2'-deoxyribose. All animal RNA viruses have Asn at the structurally homologous position of their polymerases, suggesting a conserved function for this residue. However, all prokaryotic RNA viruses have Glu at this position. In the presence of Mg2+, the apparent affinity of Glu-297 3Dpol for 2'-deoxyribonucleotides was decreased by 6-fold relative to wild type without a substantial difference in the fidelity of 2'-dNMP incorporation. The fidelity of ribonucleotide misincorporation for Glu-297 3Dpol was reduced by 14-fold relative to wild type. A 4- to 11-fold reduction in the rate of ribonucleotide incorporation was observed. Glu-297 PV was unable to grow in HeLa cells due to a replication defect equivalent to that observed for a mutant PV encoding an inactive polymerase. Evaluation of the protein-(VPg)-primed initiation reaction showed that only half of the Glu-297 3Dpol initiation complexes were capable of producing VPg-pUpU product and that the overall yield of uridylylated VPg products was reduced by 20-fold relative to wild-type enzyme, a circumstance attributable to a reduced affinity for UTP. These studies identify the first RdRp derivative with a mutator phenotype and provide a mechanistic basis for the elevated mutation frequency of RNA phage relative to animal RNA viruses observed in culture. Although protein-primed initiation and RNA-primed elongation complexes employ the same polymerase active site, the functional differences reported here imply significant structural differences between these complexes.

Trends in testing behaviours for hepatitis C virus infection and associated determinants: results from population-based laboratory surveillance in Alberta, Canada (1998-2001)

Little is currently known about hepatitis C virus (HCV) test seeking behaviours at the population level. Given the centralized nature of testing for HCV infection in the province of Alberta, Canada, we had an opportunity to examine HCV testing behaviour at the population level on all newly diagnosed HCV-positive cases using laboratory data to validate the time and number of prior tests for each case. Record linkage identified 3323, 2937, 2660 and 2703 newly diagnosed cases of HCV infections in Alberta during 1998, 1999, 2000 and 2001, respectively, corresponding to age-adjusted rates of 149.8, 129, 114.3 and 113.7 per 100,000 population during these years, respectively. Results from secondary analyses of laboratory data suggest that the majority of HCV cases (95.3%) who were newly diagnosed between 1998 and 2001 were first-time testers for HCV infection. Among repeat testers, analysis of a negative test result within 1 year prior to a first of a positive test report suggests that 211 (38.4%) may be seroconvertors. These findings suggest that 339 or 61.7% of repeat testers may not have discovered their serostatus within 1 year of infection. Among this group, HCV testing was sought infrequently, with a median interval of 2.3 years between the last negative and first positive test. This finding is of concern given the risks for HCV transmission, particularly if risk-taking behaviours are not reduced because of unknown serostatus. These findings also reinforce the need to make the most of each test-seeking event with proper counselling and other appropriate support services.

Acute hepatitis C in Israel: a predominantly iatrogenic disease?

BACKGROUND AND AIMS

Acute hepatitis C virus infection in the era of universal screening of blood products has not disappeared, and is thought to be transmitted primarily via injecting drug use. A growing body of evidence supports iatrogenic transmission as an important mode of transmission. The aim of this study was to examine transmission routes and clinical characteristics in a group of patients with acute hepatitis C in Israel.

METHODS

A retrospective chart review was conducted in three different liver clinics in Israel, of all new hepatitis C patients. Patients identified as possible acute hepatitis C were re-interviewed and all other sources such as blood bank records and pre-employment check-ups reviewed in order to establish the diagnosis of acute hepatitis C infection and to identify the transmission route.

RESULTS

Twenty-nine patients were found to have acute hepatitis C, representing 0.75% of all new referrals for hepatitis C. The most frequent (65%) mode of transmission was iatrogenic involving several, often minimal, procedures and clinical settings. The group in which iatrogenic transmission was suspected was older and the patients more often in monogamous relationship compared with other transmission routes groups. Injecting drug use was the second most common route of infection. Spontaneous seroconversion has occurred in approximately one third of the patients.

CONCLUSIONS

Acute hepatitis C in the post universal blood products screening era was found to be predominantly an iatrogenic disease in the investigated localities. This finding should direct attention and resources towards the development and implementation of preventive measures.

Estimating the future health burden of chronic hepatitis C and human immunodeficiency virus infections in the United States

The aim of this work was to estimate the future disease burden of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections in the United States until the year 2030. Two back-calculation models of the HIV and the HCV epidemic were developed. They were based on US epidemiological data regarding prevalence, age and gender of incident cases, AIDS, hepatocellular carcinoma (HCC) mortality and general population mortality from the Centers for Disease Control and WHO. Based on the HCV back-calculation model, HCV incidence peaked in 1984 at 350,000 new infections and then fell to about 77,000 in 1998. Based on the HIV back-calculation model, HIV incidence reached its maximum in 1989 at 142,000 new infections and then declined to 79,000 in 1998. Mortality related to HCV (death from liver failure or HCC) rose from about 3,700 in 1998 and is expected to peak at about 13,000 in 2030. Predicted HCV mortality would fall only if increased access to or more effective antiviral therapy occurs. For comparison, observed HIV-related mortality was 14,400 in 1998 and projected to be 4,200 for 2030. With the availability of effective highly active antiretroviral therapy for HIV infection, mortality from HIV appears to have declined substantially, whereas HCV-related deaths as a result of pre-1999 infections will likely continue to increase over the next 25 years.

Follow-up for medical care among drug users with hepatitis C

Prevalence of hepatitis C (HCV) in injection drug users (IDUs) is high and once HCV has been detected, follow-up medical care is essential. Six hundred and one current and former IDUs who tested positive for HCV antibodies received referrals for medical care. Twenty-four percent (147) of participants returned to be interviewed regarding their medical follow-ups. Of these, only 42% (61) had sought additional medical care in the form of further liver or blood tests or liver ultrasound. Four variables predicted seeking medical care: (a) ever being in residential drug treatment, (b) ever trading sex for money, (c) self-reported homelessness, and (d) living in one's own apartment or house. Having income from a job was inversely associated with seeking medical care. Knowledge of HCV infection alone does not mean that IDUs will seek medical care. Additional education concerning medical care and treatment options are needed to address IDU needs.

Small interfering RNA targeted to hepatitis C virus 5' nontranslated region exerts potent antiviral effect

Hepatitis C virus (HCV) is a major cause of cirrhosis and hepatocellular carcinoma. Interferon alone or together with ribavirin is the only therapy for HCV infection; however, a significant number of HCV-infected individuals do not respond to this treatment. Therefore, the development of new therapeutic options against HCV is a matter of urgency. In the present study, we have examined vectors carrying short hairpin RNA (shRNA) targeting the 5' nontranslated conserved region of the HCV genome for inhibition of virus replication. Initially, three sequences were selected, and all three shRNAs (psh-53, psh-274, and psh-375) suppressed HCV internal ribosome entry site (IRES)-mediated translation to different degrees in Huh-7 cells. Next, we introduced siRNA into Huh-7.5 cells persistently infected with HCV genotype 2a (JFH1). The most efficient inhibition of JFH1 replication was observed with psh-274, targeted to the portion from subdomain IIId to IIIe of the IRES. Subsequently, Huh-7.5 cells stably expressing psh-274 further displayed a significant reduction in HCV JFH1 replication. The effect of psh-274 on cell-culture-grown HCV genotype 1a (H77) was also evaluated, and inhibition of virus replication and infectivity titers was observed. In the absence of a cell-culture-grown HCV genotype 1b, the effects of psh-274 on subgenomic and full-length replicons were examined, and efficient inhibition of genome replication was observed. Therefore, we have identified a conserved sequence targeted to the HCV genome that can inhibit replication of different genotypes, suggesting the potential of siRNA as an additional therapeutic modality against HCV infection.

Hepatitis C: a challenge to hepatologists and to the liver transplantation team

Hepatitis C is the main cause of cirrhosis and hepatocellular carcinoma and the leading indication of liver transplantation. The aim of this article was to review specific epidemiological, clinical and therapeutic aspects of hepatitis C and their implication for the hepatologists belonging to liver transplantation services. These specific aspects were reviewed in the literature mainly using Medline. Data regarding the epidemiological, clinical and therapeutic aspects of hepatitis C are discussed, with emphasis on their consequences for the liver transplantation team. Hepatitis C is a challenge for hepatologists and for the liver transplantation team. The burden we observe today is the late consequence of infection that occurred in the past. Measures for early recognition of complications of liver disease are recommended. HCV treatment should always be performed before liver transplantation if possible, but if not, HCV recurrence should be recognized and treated early after transplantation.

Comparison of hepatitis C treatment patterns in patients with and without psychiatric and/or substance use disorders

Hepatitis C virus (HCV) infection is more frequent in veterans than in nonveterans. Up to 85% of HCV-infected veterans have psychiatric and/or substance use (SU) co-morbidities which, prior to the 2002 NIH Consensus Conference, were considered relative contraindications to antiviral therapy, assuming a poor adherence. With the objective of evaluating the validity of this assumption, we compared eligibility, completion and response to antiviral therapy in HCV-infected veterans with and without these comorbidities. Veterans who were anti-HCV-positive and had been seen at least once in the liver clinic (between October 1999 and June 2002) were identified through the CT-VAHCS database. Records were reviewed for patient demographics and status of liver disease, assessment of treatment eligibility, type of therapy, completion of therapy and virological response. Patients with active mental illness (MI) or SU were compared with those without these comorbidities (controls). Of 697 anti-HCV-positive-patients, 647 HCV-RNA-positive patients were included, 294 with MI/SA and 353 controls. Patient demographics, viral and liver disease characteristics were comparable between groups. Patients with MI/SA were considered ineligible for therapy more frequently (53%vs 39%, P < 0.001) and were treated less frequently (21%vs 28%, P = 0.03) than controls. However, completion of therapy (72%vs 59%) and sustained virological response (SVR) (20%vs 25%) did not differ significantly between groups. HCV-infected veterans with MI/SA are being offered therapy and treated less often than those without such co-morbidities, however therapy completion and SVR rates are similar, challenging the perception that adherence is poorer in this patient population.

Management of Hepatitis C Infection in the HIV-Infected Patient

Morbidity and mortality associated with HIV infection have rapidly decreased with the introduction of highly active antiretroviral therapy. Of recent concern is the increase of unusual opportunistic infections, particularly hepatitis C virus in this population. Because of the shared route of transmission, a significant number of HIV-infected patients are also coinfected with hepatitis C virus. HIV infection has been demonstrated to increase the rate of hepatitis C virus disease progression. New data on the use of pegylated interferon plus ribavirin indicate that while cure of hepatitis C virus in the coinfected patient is a clinical challenge, it is possible. Aggressive management of anemia, drug-induced depression, and drug interactions increase the opportunity for clinical response and positive patient outcomes.

A general method for nested RT-PCR amplification and sequencing the complete HCV genotype 1 open reading frame

BACKGROUND

Hepatitis C virus (HCV) is a pathogenic hepatic flavivirus with a single stranded RNA genome. It has a high genetic variability and is classified into six major genotypes. Genotype 1a and 1b cause the majority of infections in the USA. Viral genomic sequence information is needed to correlate viral variation with pathology or response to therapy. However, reverse transcription-polymerase chain reaction (RT-PCR) of the HCV genome must overcome low template concentration and high target sequence diversity. Amplification conditions must hence have both high sensitivity and specificity yet recognize a heterogeneous target population to permit general amplification with minimal bias. This places divergent demands of the amplification conditions that can be very difficult to reconcile.

RESULTS

RT and nested PCR conditions were optimized independently and systematically for amplifying the complete open reading frame (ORF) from HCV genotype 1a and 1b using several overlapping amplicons. For each amplicon, multiple pairs of nested PCR primers were optimized. Using these primers, the success rate (defined as the rate of production of sufficient DNA for sequencing with any one of the primer pairs for a given amplicon) for amplification of 72 genotype 1a and 1b patient plasma samples averaged over 95% for all amplicons. In addition, two sets of sequencing primers were optimized for each genotype 1a and 1b. Viral consensus sequences were determined by directly sequencing the amplicons. HCV ORFs from 72 patients have been sequenced using these primers. Sequencing errors were negligible because sequencing depth was over 4-fold and both strands were sequenced. Primer bias was controlled and monitored through careful primer design and control experiments.

CONCLUSION

Optimized RT-PCR and sequencing conditions are useful for rapid and reliable amplification and sequencing of HCV genotype 1a and 1b ORFs.

Influence of recent advances in medical management on clinical outcomes of cirrhosis

Cirrhosis and its disease-related complications are the 12th leading cause of mortality among U.S. adults and are the 5th leading cause of death for individuals aged 45 to 54 years. Hospitalization costs for disease-related complications are estimated at 18,000 dollars per episode of care, and 10% of admitted patients die. Despite these ominous findings, the survival rate of patients with cirrhosis has improved during the past 2 decades. This observation coincides with the conducting and reporting of high-quality randomized controlled trials and observational studies. Therefore, the improved prognosis in cirrhosis may be related to the effective translation of research findings to clinical practice for this patient population. Although explicit data to support this claim are not available, this article reviews the reported trends in clinical outcomes for patients with cirrhosis and the existence of evidence-based medical information that is available to care for these chronically ill patients.

Hepatitis C is a predictor of poorer renal survival in diabetic patients

OBJECTIVE

Hepatitis C virus (HCV) is highly prevalent in the U.S. and worsens renal survival in some kidney diseases. We examined the effects of HCV on renal survival in diabetic patients with renal disease.

RESEARCH DESIGN AND METHODS

HCV and diabetes status were noted in patients seen in our nephrology clinic in 2001 and 2002. Charts of diabetic patients were reviewed for demographics, blood pressure, renal function, medicines, the presence of HCV, and other factors at the initial visit and over follow-up. The effect of HCV on renal survival was determined by Cox proportional hazards, using end-stage renal disease (ESRD) as an end point.

RESULTS

Of 1,127 patients, prevalence rates for HCV were higher in African Americans than non-African Americans (8.09 vs. 3.93%, respectively, P = 0.06), with African-American men having the highest prevalence rates (12.7%). The charts of 312 diabetic patients were reviewed. Over 80% were African American, as were 23 of 24 patients with HCV. Compared with non-HCV patients, HCV patients were younger, had higher diastolic blood pressure, and had lower BMI. HCV patients had significantly worse cumulative renal survival by Kaplan-Meier. On Cox proportional hazards analysis, HCV was a significant predictor of reaching ESRD independent of initial renal function, proteinuria, blood pressure, sex, race, presence of diabetic nephropathy, age, or duration of diabetes (odds ratio 3.49, 95% CI 1.27-9.57, P = 0.015).

CONCLUSIONS

HCV is common in African Americans with diabetes and renal disease and is an independent risk factor for renal survival in this population. Prospective studies are necessary to confirm these observations.

Hepascore: an accurate validated predictor of liver fibrosis in chronic hepatitis C infection

BACKGROUND

Staging hepatic fibrosis by liver biopsy guides prognosis and treatment of hepatitis C, but is invasive and expensive. We sought to create an algorithm of serum markers that accurately and reliably predict liver fibrosis stage among hepatitis C patients.

METHODS

Ten biochemical markers were measured at time of liver biopsy in 117 untreated hepatitis C patients (training set). Multivariate logistic regression and ROC curve analyses were used to create a predictive model for significant fibrosis (METAVIR F2, F3, and F4), advanced fibrosis (F3 and F4), and cirrhosis (F4). The model was validated in 104 patients from other institutions.

RESULTS

A model (Hepascore) of bilirubin, gamma-glutamyltransferase, hyaluronic acid, alpha(2)-macroglobulin, age, and sex produced areas under the ROC curves (AUCs) of 0.85, 0.96, and 0.94 for significant fibrosis, advanced fibrosis, and cirrhosis, respectively. In the training set, a score > or = 0.5 (range, 0.0-1.0) was 92% specific and 67% sensitive for significant fibrosis, a score <0.5 was 81% specific and 95% sensitive for advanced fibrosis, and a score <0.84 was 84% specific and 71% sensitive for cirrhosis. Among the validation set, the AUC for significant fibrosis, advanced fibrosis, and cirrhosis were 0.82, 0.90, and 0.89, respectively. A score > or = 0.5 provided a specificity and sensitivity of 89% and 63% for significant fibrosis, whereas scores <0.5 had 74% specificity and 88% sensitivity for advanced fibrosis.

CONCLUSIONS

A model of 4 serum markers plus age and sex provides clinically useful information regarding different fibrosis stages among hepatitis C patients.

Safety and efficacy of peginterferon plus ribavirin in patients with chronic hepatitis C and bridging fibrosis or cirrhosis

The combination of pegylated interferon and ribavirin is the most effective therapy in patients with chronic hepatitis C. We evaluated this combination in unselected patients with bridging fibrosis or cirrhosis. Eighty patients were treated with peginterferon alpha-2b plus ribavirin. Hepatitis C virus serum RNA was monitored. Tolerance and safety were evaluated by the rate of treatment's discontinuation for any reason, and occurrence of serious clinical adverse events, respectively. Sustained virologic response (SVR) rate was 36.3% overall, and was observed in every group of patients except those who had previously failed to respond to the combination of interferon and ribavirin. No serious clinical adverse event occurred. Treatment was withdrawn in 18.7% of patients. Variables associated with discontinuation of treatment were low prothrombin index [OR: 1.16 (1.05;1.27)] and low body mass index [OR: 1.47 (1.12;1.92)]. Initial blood count abnormalities were not associated with cessation of treatment. Furthermore, early virologic response at week 8 and week 12 of treatment had similar predictive value for SVR. Combination therapy with peginterferon plus ribavirin seems effective in this group of patients, except in those who had previously failed to respond to the combination of interferon and ribavirin. This therapy is safe with appropriate monitoring, but tolerance seems worse in patients with the most advanced liver disease.

Chronic hepatitis C treatment patterns in African American patients: an update

There are large racial disparities in the incidence of chronic hepatitis C virus (HCV) infection in the United States. The prevalence of HCV, and the prevalence of infection with HCV genotype 1, is higher among African Americans than among other ethnic groups. African Americans also have a higher incidence of complications of HCV infection, including a higher incidence of antibodies to HCV RNA and higher incidences of occurrence of and mortality from hepatocellular carcinoma. Combination therapy with pegylated interferons and ribavirin has increased the sustained virologic response (SVR) rates, and decreased the rates and severity of adverse events, over those observed with standard interferons, with or without ribavirin, although SVR rates with peginterferons plus ribavirin are lower in African Americans than in other ethnic groups. A recent clinical trial of peginterferon alpha-2a plus ribavirin in African American patients resulted in a higher SVR rate, 26%, than observed previously, and 90% of patients showed stabilization or improvement in fibrosis. No host or viral genetic differences have yet been identified to explain the racial disparities in incidence of HCV or response to treatment, but clinical trials are currently ongoing to identify these factors. Because treatment with pegylated interferons plus ribavirin yields improved SVR rates with good tolerability, while the basis for lower response rates in African Americans is not yet known, it is recommended that all patients with chronic HCV infection, regardless of ethnic or racial background, receive combination therapy.

The road to new antiviral therapies

Viral diseases continue to pose some of the greatest challenges to modern medicine. For many viral diseases, prophylactic vaccines are unlikely to be developed in the near future. Fortunately, effective antiviral therapies have been developed for many of these viruses. In this review, I will focus on antiviral therapy for herpes simplex virus, human immunodeficiency virus, hepatitis C virus, and human papillomavirus. The development of compounds targeting these viruses illustrates many of the principles driving current antiviral development. It is likely that our increasing understanding of viral replication and the virus-host interaction will lead to more rapid development of new antivirals in the future.

Involvement of a bovine viral diarrhea virus NS5B locus in virion assembly

A novel mutant of bovine viral diarrhea virus (BVDV) was found with a virion assembly phenotype attributable to an insertion into the NS5B polymerase locus. This mutant, termed 5B-741, was engineered by reverse genetics to express NS5B with a C-terminal peptide tag of 22 amino acids. Electroporation of bovine cells with genomic RNA from this mutant showed levels RNA synthesis which were regarded as sufficient for infectivity, yet infectious virions were not produced. Pseudorevertants of mutant 5B-741 that released infectious virions and formed plaques revealed a single nucleotide change (T12369C). This change resulted in a leucine-to-proline substitution within the NS5B tag (L726P). Genetic analysis revealed that indeed a single nucleotide change encoding proline at NS5B position 726 in the pseudorevertant polyprotein mediated recovery of virion assembly function without improving genomic RNA accumulation levels. A subgenomic BVDV reporter replicon (rNS3-5B) was used to analyze the consequences of alterations of the genomic region encoding the NS5B C terminus on replication and assembly. Interestingly, rNS3-5B-L726P (revertant) replicated with the same efficiency as the rNS3-5B-741 mutant but produced 10 times more virions in a trans-packaging assay. These results indicated that impairment of assembly function in 5B-741 was independent of RNA accumulation levels and agreed with the observations from the full-length mutant and revertant genomes. Finally, we recapitulated the packaging defect of 5B-741 with a vaccinia virus expression system to eliminate possible unwanted interactions between the helper virus and the packaged replicon. Taken together, these studies revealed an unexpected role of NS5B in infectious virion assembly.

Epidemiology, Diagnosis, and Treatment of Chronic Hepatitis C

The hepatitis C virus (HCV) is a leading cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma and is also a common indication for liver transplantation. Interferon alfa monotherapy leads to a sustained virologic response in only 10% to 15% of HCV-infected patients. The sustained virologic response rates can be increased to approximately 40% with interferon alfa-2b and ribavirin combination therapy for up to 48 weeks. However, recent clinical trials demonstrated that pegylated interferon in combination with ribavirin can improve the response rates even further, with more than 50% of patients having a sustained virologic response to treatment. Although new therapies are emerging, significant progress must be made to reduce the morbidity and mortality from HCV infection.

Hepatocyte proliferation in chronic hepatitis C: correlation with degree of liver disease and serum alpha-fetoprotein

AIMS

Hepatocyte proliferation (HP) is an adaptive response to liver injury. The relationships between HP and necroinflammation, fibrosis, and serum alpha-fetoprotein (AFP) levels in chronic hepatitis C virus (HCV) infection, however, are not well understood.

METHODS

Proliferative hepatocytes (Ki-67+) were identified using immunohistochemical staining in formalin-fixed, paraffin-embedded liver tissue from 156 HCV RNA-positive patients with different degrees of liver histopathology. Twenty high-power fields (HPFs) in lobular areas were counted in each specimen.

RESULTS

HP increased by 1.22 +/- 0.25 cells/HPF per increase in necroinflammation from grade 0 (median: 0.13; range: [0.1-0.5] cells/HPF) through grade 3 (median: 1.80; range: [0.0-25.2] cells/HPF; P=0.002). HP increased by 0.81 +/- 0.20 cells/HPF per increase in fibrosis from stage 0 (median: 0.33; range: [0.0-1.3] cells/HPF) through stage 3 (median: 1.70; range: [0.0-25.2] cells/HPF) and then decreased in stage 4 (to median: 0.90; range: [0.0-5.3] cells/HPF). HP also increased with advancing age (P=0.03). Among patients with advanced liver disease, HP was no higher in patients with elevated serum AFP levels (median: 1.68; range: [0.1-5.3] cells/HPF) than in those with normal serum AFP levels (median: 1.70; range: [0.0-25.2] cells/HPF; P=0.26).

CONCLUSIONS

In patients with chronic HCV infection, HP increases with histologic progression of liver disease, but is impaired in cirrhosis. HP was not increased in patients with elevated serum AFP levels.

Resection of hepatocellular carcinoma in patients otherwise eligible for transplantation

INTRODUCTION

The incidence of hepatocellular carcinoma (HCC) in the United States has increased 75% in the last decade. Liver transplantation is gaining acceptance for the treatment of early HCC, even in patients with adequate liver function. The objective of this study was to determine the long-term outcome of patients with early HCC who would have been candidates for transplantation but were treated instead with partial hepatectomy.

METHODS

From August 1989 to November 2001, 611 patients with HCC were evaluated at our institution and entered into a prospective database. There were 180 (29%) patients who underwent partial hepatectomy, of whom 36 (20%) satisfied the currently accepted criteria for transplantation: 2 or 3 lesions each </= 3 cm in size or a solitary tumor </= 5 cm. Survival was determined by Kaplan-Meier analysis.

RESULTS

Median tumor size was 3.5 (range, 1.8-5) cm and the median number of lesions was 1 (range, 1-3). Patients had pathologically confirmed cirrhosis of the liver in 78% (28/36) of cases, and 86% had normal liver function (Child class A). Perioperative morbidity was 25%, the median length of hospital stay was 8 (range, 4-24) days, and there was 1 (2.8%) perioperative death. At a median follow-up of 35 months for survivors, the 1-, 3-, and 5-year overall survival was 85%, 74%, and 69%, respectively, with a median survival of 71 months. The 5-year disease-free survival was 48% with a median of 52 months.

CONCLUSIONS

Partial hepatectomy in patients with early HCC who are otherwise eligible for transplantation can be performed with minimal morbidity and can achieve comparable 5-year survival to that reported for liver transplantation. Resection should be considered the standard therapy for patients with HCC who have adequate liver reserve.

Resection of hepatocellular carcinoma in patients otherwise eligible for transplantation

INTRODUCTION

The incidence of hepatocellular carcinoma (HCC) in the United States has increased 75% in the last decade. Liver transplantation is gaining acceptance for the treatment of early HCC, even in patients with adequate liver function. The objective of this study was to determine the long-term outcome of patients with early HCC who would have been candidates for transplantation but were treated instead with partial hepatectomy.

METHODS

From August 1989 to November 2001, 611 patients with HCC were evaluated at our institution and entered into a prospective database. There were 180 (29%) patients who underwent partial hepatectomy, of whom 36 (20%) satisfied the currently accepted criteria for transplantation: 2 or 3 lesions each </= 3 cm in size or a solitary tumor </= 5 cm. Survival was determined by Kaplan-Meier analysis.

RESULTS

Median tumor size was 3.5 (range, 1.8-5) cm and the median number of lesions was 1 (range, 1-3). Patients had pathologically confirmed cirrhosis of the liver in 78% (28/36) of cases, and 86% had normal liver function (Child class A). Perioperative morbidity was 25%, the median length of hospital stay was 8 (range, 4-24) days, and there was 1 (2.8%) perioperative death. At a median follow-up of 35 months for survivors, the 1-, 3-, and 5-year overall survival was 85%, 74%, and 69%, respectively, with a median survival of 71 months. The 5-year disease-free survival was 48% with a median of 52 months.

CONCLUSIONS

Partial hepatectomy in patients with early HCC who are otherwise eligible for transplantation can be performed with minimal morbidity and can achieve comparable 5-year survival to that reported for liver transplantation. Resection should be considered the standard therapy for patients with HCC who have adequate liver reserve.

RNA interference blocks gene expression and RNA synthesis from hepatitis C replicons propagated in human liver cells

RNA interference represents an exciting new technology that could have therapeutic applications for the treatment of viral infections. Hepatitis C virus (HCV) is a major cause of chronic liver disease and affects >270 million individuals worldwide. The HCV genome is a single-stranded RNA that functions as both a messenger RNA and replication template, making it an attractive target for the study of RNA interference. Double-stranded small interfering RNA (siRNA) molecules designed to target the HCV genome were introduced through electroporation into a human hepatoma cell line (Huh-7) that contained an HCV subgenomic replicon. Two siRNAs dramatically reduced virus-specific protein expression and RNA synthesis to levels that were 90% less than those seen in cells treated with negative control siRNAs. These same siRNAs protected naive Huh-7 cells from challenge with HCV replicon RNA. Treatment of cells with synthetic siRNA was effective >72 h, but the duration of RNA interference could be extended beyond 3 weeks through stable expression of complementary strands of the interfering RNA by using a bicistronic expression vector. These results suggest that a gene-therapeutic approach with siRNA could ultimately be used to treat HCV.

Peginterferon-alpha-2a (40kD) plus ribavirin: a review of its use in the management of chronic hepatitis C

Pegylation of interferon-alpha-2a is associated with improved sustained virological response rates in patients with chronic hepatitis C. Subsequently, combination therapy with peginterferon-alpha-2a (40kD) [Pegasys] and ribavirin (Copegus trade mark, Rebetol) was investigated to establish if the efficacy of peginterferon-alpha-2a (40kD) monotherapy could be further enhanced. Subcutaneous peginterferon-alpha-2a (40kD) was administered at a dosage of 180 micro g once weekly and oral ribavirin was usually administered at a dosage of 1000 or 1200 mg/day. In treatment-naive patients with chronic hepatitis C, the sustained virological response rate (assessed 24 weeks after the end of a 48-week treatment period) was significantly higher in peginterferon-alpha-2a (40kD) plus ribavirin recipients than in peginterferon-alpha-2a (40kD) plus placebo recipients or interferon-alpha-2b plus ribavirin recipients (56% vs 29% and 44%). Retrospective analysis revealed that peginterferon-alpha-2a (40kD) plus ribavirin recipients who did not achieve an early virological response were unlikely to achieve a sustained response. Treatment with peginterferon-alpha-2a (40kD) plus another antiviral agent (ribavirin, mycophenolate mofetil, amantadine, or ribavirin and amantadine) was beneficial in patients with chronic hepatitis C who had relapsed during or after, or had not responded to, treatment with interferon-alpha-2b plus ribavirin. In the relapse study, sustained virological response rates in recipients of peginterferon-alpha-2a (40kD) plus ribavirin were 45% with and 38% without amantadine. Peginterferon-alpha-2a (40kD) plus ribavirin appears beneficial in patients with chronic hepatitis C considered difficult to treat (e.g. patients infected with hepatitis C virus genotype 4, African-American patients, patients with advanced fibrosis or cirrhosis and patients co-infected with HIV). Flu-like symptoms and depression occurred significantly less frequently with peginterferon-alpha-2a (40kD) plus ribavirin than with interferon-alpha-2b plus ribavirin. Similar proportions of patients receiving peginterferon-alpha-2a (40kD) plus ribavirin, peginterferon-alpha-2a (40kD) plus placebo and interferon-alpha-2b plus ribavirin withdrew from treatment because of laboratory abnormalities or other adverse events. In conclusion, combination therapy comprising subcutaneous peginterferon-alpha-2a (40kD) and oral ribavirin is an important new treatment option for chronic hepatitis C. Peginterferon-alpha-2a (40kD) plus oral ribavirin is significantly more effective than peginterferon-alpha-2a (40kD) monotherapy or interferon-alpha-2b plus ribavirin at inducing a sustained virological response in treatment-naive patients with chronic hepatitis C. Preliminary data suggest that peginterferon-alpha-2a (40kD) plus ribavirin is also beneficial in treatment-experienced patients and in patients who have traditionally been considered difficult to treat. Combination therapy with peginterferon-alpha-2a (40kD) and oral ribavirin is poised to become a valuable first-line treatment option in chronic hepatitis C.