Evolution of hepatitis C virus quasispecies in patients with severe cholestatic hepatitis after liver transplantation

Hepatitis C virus intrinsic molecular determinants may contribute to the development of cholestatic hepatitis after liver transplantation

Cholestatic hepatitis C (CHC) is a severe form of hepatitis C virus (HCV) infection recurrence that leads to high graft loss rates early after liver transplantation (LT). To investigate the pathogenic mechanisms of CHC, we analysed HCV quasispecies in CHC patients compared to a control group (mild hepatitis C recurrence) by deep pyrosequencing. At the time of LT, NS5B quasispecies complexity was similar between the two groups but, after LT, it decreased more sharply in CHC patients than in the control group. Interestingly, the major variant before LT propagated efficiently and remained as the dominant sequence after LT in 62 % of CHC patients versus 11 % of controls (P=0.031). Sequence analysis of the complete non-structural region in a limited number of patients revealed a potential 12 aa signature specific to the CHC group. These data suggest that intrinsic molecular determinants in the circulating HCV quasispecies may provide a fitness advantage, contributing to the development of CHC.

Fibrosing Cholestatic Hepatitis C After Liver Transplantation: Therapeutic Options Before and After Introduction of Direct-Acting Antivirals: Our Experience and Literature Review

BACKGROUND

Cirrhosis caused by hepatitis C is the most common indication for liver transplantation. The most aggressive form of hepatitis C virus (HCV) relapse after liver transplantation is fibrosing cholestatic hepatitis C, which can be observed in 2% to 15% of recipients.

METHODS

Double therapy with peg-interferon and ribavirin was characterized by low antiviral response, rapid fibrosis, and frequent graft failure within 1 year after surgery.

RESULTS

Introduction of direct-acting antivirals for HCV treatment allows for more efficient therapy with less adverse reactions, including patients with fibrosing cholestatic hepatitis C.

CONCLUSIONS

We present 4 (2.5%) cases of cholestatic viral hepatitis C recurrence in patients undergoing transplantation between 2006 and 2015 at the Transplantation Institute of Warsaw; during this period, 158 liver transplants were performed in patients with cirrhosis caused by HCV infection.

Successful Treatment of Fibrosing Cholestatic Hepatitis With Daclatasvir and Asunaprevir After Liver Transplantation: A Case Report

BACKGROUND

Fibrosing cholestatic hepatitis (FCH) is an aggressive form of hepatitis C virus (HCV) recurrence after liver transplantation (LT). Most FCH cases are fatal, occurring as a secondary disease following rapidly progressive liver dysfunction and graft failure. We report a case of early-onset FCH after LT that was successfully treated using daclatasvir and asunaprevir.

CASE REPORT

A 59-year-old woman underwent living donor LT for HCV-related liver cirrhosis. However, liver function was not improved after LT and gradually worsened. A liver biopsy was performed at 30 and 47 days after the living donor LT to identify the cause of the liver dysfunction. The first biopsy result showed no specific finding. However, combined treatment with pegylated interferon and ribavirin was started because of a high HCV viral load (> 8.0 log IU/mL). Nevertheless, liver function and HCV viral load deteriorated, and the second biopsy performed on postoperative day 47 revealed FCH. We converted the antiviral agents into daclatasvir and asunaprevir and performed plasmapheresis twice. Since then, the liver dysfunction and HCV viral load gradually improved, and HCV RNA clearance occurred at week 11 after treatment. The patient achieved a sustained virologic response at week 24 after completion of the treatment.

CONCLUSION

Daclatasvir combined with asunaprevir can be a useful treatment option in potentially fatal FCH after LT.

Treating fibrosing cholestatic hepatitis C with sofosbuvir and ribavirin: a matched analysis

BACKGROUND

Fibrosing cholestatic hepatitis (FCH) is an uncommon but potentially fatal complication of recurrent hepatitis C (HCV) in liver transplant recipients.

METHODS

We matched the treatment outcomes of 10 liver transplant recipients who developed FCH with those of 10 recipients with recurrent HCV without FCH treated with sofosbuvir and ribavirin.

RESULTS

Baseline mean alanine transaminase, aspartate transaminase, alkaline phosphatase, and total bilirubin were 186 U/L, 197 U/L, 243 U/L, and 6.7 mg/dL, respectively, in the FCH recipients and 82 U/L, 60 U/L, 110 U/L, and 0.99 mg/dL, respectively, in non-FCH recipients. The sustained viral response in FCH and non-FCH recipients was 40% and 80%, respectively. One-yr patient and graft survival rates were 90% and 80%, respectively, in FCH recipients, and 100% in non-FCH recipients. Seven FCH and six non-FCH recipients were treated for anemia with blood transfusion and/or erythropoietin growth factors.

CONCLUSION

Our results suggest that the use of sofosbuvir and ribavirin is effective and tolerable in liver transplant recipients treated for recurrent FCH. There is a trend of lower sustained viral response, patient survival, and graft survival in the FCH recipients.

Intensive temporal mapping of hepatitis C hypervariable region 1 quasispecies provides novel insights into hepatitis C virus evolution in chronic infection

Hepatitis C virus (HCV) is an RNA virus which exists as swarms of closely related viruses known as quasispecies (QS). A number of studies have demonstrated associations between QS hypervariable region 1 (HVR1) characteristics (diversity and complexity) and treatment success. We investigated HCV QS change in chronic infection over intervals of 2-4 weeks in 23 chronically infected individuals to describe the natural history of virus evolution and establish whether HCV QS characteristics could be used to individualize treatment regimens at a molecular level. HVR1 QS diversity, complexity and divergence continue to change in an unpredictable fashion in chronic infection even where there is little phylogenetic change, which is likely to preclude the use of these features in treatment individualization. Our phylogenetic analysis identified no change in the HVR1 QS in 12 subjects, minor change in four subjects and we describe a time-ordered phylogeny for the first time over a period as short as 16 weeks in seven subjects. We identified the existence of multiple subpopulation infections using partitioned analysis of QS and illustrated how subpopulations were sequentially replaced in a number of subjects. We illustrated marked variation in the nucleotide substitution per codon position between patients with sequence change and those without change in the phylogenetic tree. Analysis of codon-specific selection pressures identified a number of codons under purifying selection, suggesting that these code for structurally conserved amino acids. We also identified sections of the HVR1 under positive selection with marked sequence heterogeneity, suggesting that these may be potential epitope-binding sites.

Hepatitis C virus molecular evolution: Transmission, disease progression and antiviral therapy

Hepatitis C virus (HCV) infection represents an important public health problem worldwide. Reduction of HCV morbidity and mortality is a current challenge owned to several viral and host factors. Virus molecular evolution plays an important role in HCV transmission, disease progression and therapy outcome. The high degree of genetic heterogeneity characteristic of HCV is a key element for the rapid adaptation of the intrahost viral population to different selection pressures (e.g., host immune responses and antiviral therapy). HCV molecular evolution is shaped by different mechanisms including a high mutation rate, genetic bottlenecks, genetic drift, recombination, temporal variations and compartmentalization. These evolutionary processes constantly rearrange the composition of the HCV intrahost population in a staging manner. Remarkable advances in the understanding of the molecular mechanism controlling HCV replication have facilitated the development of a plethora of direct-acting antiviral agents against HCV. As a result, superior sustained viral responses have been attained. The rapidly evolving field of anti-HCV therapy is expected to broad its landscape even further with newer, more potent antivirals, bringing us one step closer to the interferon-free era.

Hepatitis C Recurrence after Orthotopic Liver Transplantation: Mechanisms and Management

Chronic Hepatitis C (HCV) infection is the leading indication for orthotopic liver transplantation and recurrence is nearly universal. Chronic HCV infection is frequently established through evasion of the innate immune system. Priming of adaptive immune responses modulate the severity and rate of fibrosis progression. Those with demonstrable viremia entering the transplant period uniformly suffer recurrence post-transplant. Progression to cirrhosis is accelerated post-transplant secondary to systemic immunosuppression. In addition, a number of factors, including donor, host, and viral characteristics, influence severity and rate of fibrosis progression. Interferon-based therapy, the previous standard of care, in those with advanced cirrhosis or post-transplant has been limited by a number of issues. These include a relative lack of efficacy and poor tolerability with higher incidence of infection and anemia. Recently, approval of direct acting antivirals have ushered in a new era in HCV therapeutics and have applicability in these special populations. Their use immediately prior to or post-transplant is expected to improve both morbidity and mortality.

Post-liver transplant hepatitis C virus recurrence: an unresolved thorny problem

Hepatitis C virus (HCV)-related cirrhosis represents the leading cause of liver transplantation in developed, Western and Eastern countries. Unfortunately, liver transplantation does not cure recipient HCV infection: reinfection universally occurs and disease progression is faster after liver transplant. In this review we focus on what happens throughout the peri-transplant phase and in the first 6-12 mo after transplantation: during this crucial period a completely new balance between HCV, liver graft, the recipient's immune response and anti-rejection therapy is achieved that will deeply affect subsequent outcomes. Nearly all patients show an early graft reinfection, with HCV viremia reaching and exceeding pre-transplant levels; in this setting, histological assessment is essential to differentiate recurrent hepatitis C from acute or chronic rejection; however, differentiating the two patterns remains difficult. The host immune response (mainly cellular mediated) appears to be crucial both in the control of HCV infection and in the genesis of rejection, and it is also strongly influenced by immunosuppressive treatment. At present no clear immunosuppressive strategy could be strongly recommended in HCV-positive recipients to prevent HCV recurrence, even immunotherapy appears to be ineffective. Nonetheless it seems reasonable that episodes of rejection and over-immunosuppression are more likely to enhance the risk of HCV recurrence through immunological mechanisms. Both complete prevention of rejection and optimization of immunosuppression should represent the main goals towards reducing the rate of graft HCV reinfection. In conclusion, post-transplant HCV recurrence remains an unresolved, thorny problem because many factors remain obscure and need to be better determined.

New insights in recurrent HCV infection after liver transplantation

Hepatitis C virus (HCV) is a small-enveloped RNA virus belonging to the Flaviviridae family. Since first identified in 1989, HCV has been estimated to infect 170 million people worldwide. Mostly chronic hepatitis C virus has a uniform natural history, from liver cirrhosis to the development of hepatocellular carcinoma. The current therapy for HCV infection consists of a combination of Pegylated interferon and ribavirin. On the other hand, HCV-related liver disease is also the leading indication for liver transplantation. However, posttransplant HCV re-infection of the graft has been reported to be universal. Furthermore, the graft after HCV re-infection often results in accelerated progression to liver failure. In addition, treatment of recurrent HCV infection after liver transplantation is often compromised by enhanced adverse effects and limited efficacy of interferon-based therapies. Taken together, poor outcome after HCV re-infection, regardless of grafts or recipients, poses a major issue for the hepatologists and transplant surgeons. The aim of this paper is to review several specific aspects regarding HCV re-infection after transplant: risk factors, current therapeutics for HCV in different stages of liver transplantation, cellular function of HCV proteins, and molecular mechanisms of HCV entry. Hopefully, this paper will inspire new strategies and novel inhibitors against recurrent HCV infection after liver transplantation and greatly improve its overall outcome.

Genetic diversity and selection regulates evolution of infectious bronchitis virus

Conventional and molecular epidemiologic studies have confirmed the ability of infectious bronchitis virus (IBV) to rapidly evolve and successfully circumvent extensive vaccination programs implemented since the early 1950s. IBV evolution has often been explained as variation in gene frequencies as if evolution were driven by genetic drift alone. However, the mechanisms regulating the evolution of IBV include both the generation of genetic diversity and the selection process. IBV's generation of genetic diversity has been extensively investigated and ultimately involves mutations and recombination events occurring during viral replication. The relevance of the selection process has been further understood more recently by identifying genetic and phenotypic differences between IBV populations prior to, and during, replication in the natural host. Accumulating evidence suggests that multiple environmental forces within the host, including immune responses (or lack thereof) and affinity for cell receptors, as well as physical and biochemical conditions, are responsible for the selection process. Some scientists have used or adopted the related quasispecies frame to explain IBV evolution. The quasispecies frame, while providing a distinct explanation of the dynamics of populations in which mutation is a frequent event, exhibits relevant limitations which are discussed herein. Instead, it seems that IBV populations evolving by the generation of genetic variability and selection on replicons follow the evolutionary mechanisms originally proposed by Darwin. Understanding the mechanisms underlying the evolution of IBV is of basic relevance and, without doubt, essential to appropriately control and prevent the disease.

Viral quasispecies evolution

Evolution of RNA viruses occurs through disequilibria of collections of closely related mutant spectra or mutant clouds termed viral quasispecies. Here we review the origin of the quasispecies concept and some biological implications of quasispecies dynamics. Two main aspects are addressed: (i) mutant clouds as reservoirs of phenotypic variants for virus adaptability and (ii) the internal interactions that are established within mutant spectra that render a virus ensemble the unit of selection. The understanding of viruses as quasispecies has led to new antiviral designs, such as lethal mutagenesis, whose aim is to drive viruses toward low fitness values with limited chances of fitness recovery. The impact of quasispecies for three salient human pathogens, human immunodeficiency virus and the hepatitis B and C viruses, is reviewed, with emphasis on antiviral treatment strategies. Finally, extensions of quasispecies to nonviral systems are briefly mentioned to emphasize the broad applicability of quasispecies theory.

NK cells, innate immunity and hepatitis C infection after liver transplantation

Liver transplantation in patients with active hepatitis C virus (HCV) infection is followed by almost universal recurrence of viral infection. The control of HCV infection has been characterized largely in terms of the HCV-specific function of T-lymphocytes and the adaptive immune response. Emerging data suggest that components of the innate immune system, including natural killer cells, have a central role in determining the nature of posttransplant HCV infection and the likelihood of response to antiviral therapy. This review examines the emerging evidence implicating innate immunity in the pathogenesis of posttransplant HCV infections and the potential therapeutic implications of these observations.

Clinical characterization of patients developing histologically-proven fibrosing cholestatic hepatitis C post-liver transplantation

AIM

  Fibrosing cholestatic hepatitis C (FCH) post-liver transplantation (LT) is an uncommon disorder with extremely poor outcome. Using stringent histological criteria, we sought to identify cases of FCH to better characterize its incidence, clinical features and outcomes.

METHODS

  From January 1991 to December 2007, 973 LT for hepatitis C virus (HCV) were performed at our center. Using the pathology database, 51 cases with a provisional diagnosis of FCH were identified. FCH was diagnosed histologically by cholestasis accompanied by thin periportal fibrous septa, ductular reaction and mild inflammation.

RESULTS

  FCH was reconfirmed in 24 recipients; seven had concurrent biliary problems. Twenty-seven cases were excluded; biopsy was unavailable in nine cases, 15 did not meet the histological criteria of FCH and three had missing clinical information. All received deceased donors at a mean age of 64.4 years (15/17 aged >50 years). Mean time from LT to FCH was 7.6 months with 16 of 17 diagnosed within 1 year of LT. At diagnosis, mean viral load was 14.4 million IU/mL, bilirubin 16.2 mg/dL, aspartate aminotransferase 262 IU/mL, alanine aminotransferase 192 IU/mL and alkaline phosphatase 299 IU/mL. All 17 patients died or required re-LT a mean of 7.8 months after the FCH diagnosis.

CONCLUSION

  FCH occurs infrequently and is typified by hyperbilirubinemia, donor age of more than 50 years, extremely high HCV RNA and specific histological changes occurring within the first several months post-LT with extremely poor patient and graft survival. Histology alone is not reliable for the diagnosis of FCH, especially in the setting of recurrent HCV with concurrent biliary problems.

Post-liver transplant cholestatic hepatitis C: a systematic review of clinical and pathological findings and application of consensus criteria

Liver transplantation is currently the only definitive modality for the treatment of end-stage liver disease due to chronic hepatitis C. However, recurrent hepatitis C after liver transplantation is nearly universal. Cirrhosis may develop in 20% of recipients within 5 years, and recurrent hepatitis C may lead to graft failure, retransplantation, and even death. A subset of recipients may develop post-liver transplant cholestatic hepatitis C (PLTCHC), which is characterized by cholestasis, hepatocyte ballooning, and rapid progression to graft failure. We present a systematic review of PLTCHC that is focused on hepatitis C-infected liver transplant recipients. We compare the pathological definitions of PLTCHC, clinical factors, management strategies, and outcomes reported in studies. We found differences among studies in the types of histological criteria used to diagnose PLTCHC during liver biopsy and in the types of clinical information provided. Three of the 12 studies published after 2003 used the definition of PLTCHC published by the first International Liver Transplantation Society expert panel consensus conference on liver transplantation and hepatitis C. We propose that studies on PLTCHC use the consensus criteria for diagnosis and suggest clinical information that should be provided in future studies with the goal of improving our understanding and management of this deadly disease.

Human liver transplantation as a model to study hepatitis C virus pathogenesis

Hepatitis C is a leading etiology of liver cancer and a leading reason for liver transplantation. Although new therapies have improved the rates of sustained response, a large proportion of patients (approximately 50%) fail to respond to antiviral treatment, thus remaining at risk for disease progression. Although chimpanzees have been used to study hepatitis C virus biology and treatments, their cost is quite high, and their use is strictly regulated; indeed, the National Institutes of Health no longer supports the breeding of chimpanzees for study. The development of hepatitis C virus therapies has been hindered by the relative paucity of small animal models for studying hepatitis C virus pathogenesis. This review presents the strengths of human liver transplantation and highlights the advances derived from this model, including insights into viral kinetics and quasispecies, viral receptor binding and entry, and innate and adaptive immunity. Moreover, consideration is given to current and emerging antiviral therapeutic approaches based on translational research results.

Virology and pathogenesis of hepatitis C virus recurrence

1. In hepatitis C virus (HCV)-infected patients undergoing liver transplantation (LT), the virus infects the liver graft immediately after transplantation. The main source of HCV infection is circulating virions. Nevertheless, some data suggest that HCV present in extrahepatic compartments may contribute to HCV infection in some cases of hepatitis C recurrence. 2. Studies on early kinetics have shown that HCV replication starts a few hours after transplantation and that HCV-RNA concentrations increase a few hours or days after the procedure, suggesting that HCV has an enormous ability to adapt to the new environment. 3. The quasispecies population may change significantly after transplantation, most likely because of the need to adapt to a new environment. There are no conclusive data supporting the role of HCV quasispecies composition and disease outcomes. 4. Persistence of HCV infection is the rule after transplantation. This is due to immunosuppression and to the immune exhaustion of the previously exposed immune system. 5. In general, HCV is not thought to be directly cytopathic. Thus, it is believed that the immune response against HCV causes liver damage. However, understanding the mechanisms of liver damage in HCV-infected LT recipients is extremely complex because of the existence of a human leukocyte antigen-mismatched organ, the preexisting virus-specific T cells that may be dysfunctional and/or tolerized, and the immunosuppression. 6. Despite the possible effect of immune-mediated liver damage, it is clear that strong immunosuppression is associated with severe forms of hepatitis C recurrence (cholestatic hepatitis, fibrosing cholestatic hepatitis, and accelerated fibrosis progression). Thus, in the absence of a strong anti-HCV immune response, HCV is able to directly (HCV proteins) or indirectly (cytokines) produce liver damage. 7. The activation of stellate cells and accelerated deposition of fibrosis are the final consequences of HCV infection in the graft. There are several mechanisms that may act synergistically to activate and perpetuate stellate cell activation in the setting of LT: ischemia-reperfusion damage, old donor age, HCV proteins, cholestasis, rejection, infection with other viruses (cytomegalovirus), and immune-mediated injury.

Post-transplant recurrent hepatitis C: immunohistochemical detection of hepatitis C virus core antigen and possible pathogenic implications

INTRODUCTION

The mechanisms by which severe cholestatic hepatitis develops after liver transplantation are not fully understood. Reports on immunohistochemical distribution of hepatitis C virus (HCV) antigens are still scarce, but recently, HCV immunostaining was suggested for early diagnosis of cholestatic forms of recurrent hepatitis C in liver grafts. After purification, Rb246 pab anticore (aa1-68) yielded specific, granular cytoplasmic staining in hepatocytes. Signal amplification through the Envision-Alkaline Phosphatase System avoided endogenous biotin and peroxidase.

AIMS/METHODS

Rb246 was applied to liver samples of explants of 12 transplant recipients, six with the most severe form of post-transplantation recurrence, severe cholestatic hepatitis (group 1) and six with mild recurrence (group 2). We also assessed immuno-reactivity at two time-points post-transplantation (median 4 and 22 months) in both groups. HCV-core Ag was semiquantified from 0 to 3+ in each time point. Serum HCV-RNA was also measured on the different time points by branched DNA.

RESULTS

In the early post-transplant time point, one patient had a mild staining (1+), two patients had a moderate staining (2+) and the other three had no staining in group 1, compared with five patients with no staining (0) and one patient with mild staining (1+) in group 2. Late post-transplant liver samples were available in nine patients, and two out of four samples in group 1 showed a mild staining, compared with no staining patients in five patients in group 2. Strikingly, on the explant samples, HCV immunostaining was strongly positive in group 1, and mildly positive in group 2. Two out of five samples showed 3+ staining, and three samples showed 2+ staining in group 1; two out of five samples showed no staining, two samples showed 1+ staining and one sample showed 2+ staining in group 2. Serum HCV-RNA was significantly higher in group 1, on both time-points post-transplantation. HCV-core Ag was not directly associated with serum HCV-RNA on the different time points.

CONCLUSION

These preliminary results suggest that strong HCV immunostaining in the explant is predictive of more severe disease recurrence.

Evolution of the NS3 and NS5B regions of the hepatitis C virus during disease recurrence after liver transplantation

In patients with hepatitis C virus (HCV)-related cirrhosis, infection recurrence is universal after liver transplantation (LT). The relevance of host and virus-related factors on the outcome of hepatitis C recurrence is poorly understood. This study analyzed the relationship between the genetic evolution of the Non-Structural (NS)3 protease and NS5B polymerase regions of HCV and the severity of hepatitis C recurrence. Thirty-three patients were classified as having mild (n = 16) or severe recurrence (n = 17), according to the degree of fibrosis in liver biopsies obtained 1 year after transplantation. Viral load and consensus sequences of the NS3 and NS5B domains were determined in a pre-LT and in four post-LT sequential serum samples. At week 12 after LT, viremia was significantly higher in patients with severe recurrence. NS3 and NS5b regions evolved independently after LT. The genetic evolution of NS3 domain was not related to the severity of the recurrence. However, the diversification in the NS5B region later than 12 weeks after LT was greater in patients with mild than in those with severe recurrence, suggesting a stronger immune pressure in the first group. These observations highlight the complex interplay between viral evolution and clinical outcomes in the LT setting.

Genetic similarity of hepatitis C virus and fibrosis progression in chronic and recurrent infection after liver transplantation

The effect of hepatitis C virus (HCV) genetic heterogeneity on clinical features of post-transplantation hepatitis C is controversial. Different regions of the HCV genome have been associated with apoptosis, fibrosis, and other pathways leading to liver damage in chronic HCV infection. Besides, differences in immunodominant regions, such as NS3, may influence HCV-specific immune responses and disease outcome. In the liver transplant setting, a recent study has reported a positive association between HCV-1b Core region genetic relatedness 5-year post-transplantation and histological severity of recurrent hepatitis C. We have compared nucleotide sequences of HCV Core, NS3 and NS5b regions in HCV-1b-infected patients 3 years post-transplantation (n = 22). A cohort of nontransplanted patients (n = 22) was used as control of natural chronic HCV-1b infection. Histological evaluation was used to define the rate of fibrosis progression. Molecular variance analysis did not show significant differences in HCV sequences between transplanted and nontransplanted patients, or between those with fast or slow fibrosis progression. The same results were obtained when analysing phylogenetic trees for Core, NS3 and NS5b regions. A more appropriate clustering method (using minimum spanning networks) revealed a significant positive relationship between HCV genetic similarity in Core (r = 0.550, P < 0.01) and NS5b regions (r = 0.847, P < 0.01) and the yearly rate of fibrosis progression in nontransplanted patients which, in contrast, was not observed in transplanted patients. Our results indicate that some strains of HCV-1b might be more pathogenic in the natural course of chronic infection by this virus subtype. In the liver transplant setting, when the immune response is severely compromised, other mechanisms are probably more important in determining hepatitis C progression.

Morphologic Features of Hepatitis C Recurrence in Patients After Orthotopic Liver Transplantation-Preliminary Analysis of our Case Observations

INTRODUCTION

Hepatitis C virus (HCV) recurrence is almost universal in patients after liver transplantation. The diagnosis of reinfection is more difficult than that of a primary process, as shown by our pathomorphologic analysis of cases of HCV recurrence.

MATERIAL

During 5.5 years, 240 liver biopsies included 54 obtained from liver transplant recipients with primary HCV infections, among whom 26 (56.5%) had clinical signs and symptoms of hepatitis. Nineteen patients from this population underwent 30 liver biopsies. In addition, seven biopsies were performed in five patients without clinical signs of reinfection.

RESULTS

In 44.2% of patients with HCV recurrence and 15% without reinfection, the intensity of the primary process in the native livers was assessed as high. Reinfection was found in all patients with liver carcinoma and 67% with hepatocyte dysplasia. Histologic signs of infection were estimated as minimal (n = 4), mild (n = 19), or moderate (n = 4). In five patients with reinfections and one without recurrence, histologic manifestations of acute rejection were also observed. In conclusion, HCV was the indication for liver transplantation in 22.4% cases. Clinical manifestation of recurrence was found in 56.5% of the patients, who tended to be older than those without disease recurrence. Upon microscopy, lobular lesions predominated over the portal changes. Factors predisposing to HCV recurrence were coexistence of other liver disorders, a high intensity of the inflammatory process, hepatocyte dysplasia, and/or hepatocellular carcinoma in the native liver and acute rejection episodes.

The Importance of Clinical Parameters When Differentiating Cholestatic Hepatitis C Virus From Allograft Rejection

BACKGROUND

The exact cause and appropriate treatment for cholestasis following liver transplantation in recipients with hepatitis C virus recurrence (RHCV) are difficult to determine. Our objective was to determine the diagnostic accuracy of clinical and histological parameters in liver transplant recipients with RHCV and concurrent cholestasis.

METHODS

A retrospective analysis from June 1996 to May 2003 was performed on adult liver transplant (OLT) recipients with hepatitis C virus. Patients with cholestasis (bilirubin >5 mg/dL, 6 months after OLT) were selected. Demographics, etiology, immune suppression, clinical and histologic outcomes, and virologic features were evaluated. Patients were divided into two groups based on clinical and histological criteria: (1) patients with parameters suggestive of cholestatic HCV; and (2) patients with parameters consistent with acute cellular rejection.

RESULTS

Thirty-seven patients met study criteria (20 males). The average age was 54 years (range = 14-72), and time from transplant to jaundice was 769 days (range = 48-2981). The groups were comparable regarding HCV viral load, age, gender, time from transplant, and United Network of Organ Sharing status at time of transplant. Retransplantation was performed in two patients in group 1, neither of whom survived, and in three patients in group 2, all of whom survived. Clinical parameters correlated well with diagnosis of cholestasis (r = 0.85, P < .001) whereas histological evaluation did not (r = 0.11, P = .53). Mortality in group 1 was 78% (7 of 9) vs. 50% (13 of 26) in group 2. Median duration of survival following liver transplantation in group 1 was 132 days versus 435 days in group 2.

CONCLUSION

Clinical diagnosis parameters for RHCV with cholestasis appear more accurate than histology parameters and should be the primary consideration in directing therapy. Despite timely diagnosis, cholestatic RHCV LTx recipients have a poor prognosis.

Hepatitis C virus infection of primary tupaia hepatocytes leads to selection of quasispecies variants, induction of interferon-stimulated genes and NF-κB nuclear translocation

Systems for in vitro culture of Hepatitis C virus (HCV) are essential tools to analyse virus–cell interactions and to investigate relevant pathophysiological aspects of HCV infection. Although the HCV replicon methodology has increased our understanding of HCV biology, this system does not reproduce the natural infection. Recently, tupaia (Tupaia belangeri chinensis) hepatocytes have been utilized for in vitro culture of HCV. In the present work, primary tupaia hepatocytes infected in vitro with HCV were used to analyse the evolution of HCV quasispecies in infected cells and the ability of the virus to influence antiviral and proinflammatory responses in cells sustaining virus replication. The results confirmed the potential of tupaia hepatocytes as a model for HCV infection, although this system is limited by rapid loss of differentiated cell phenotype in culture. These findings revealed an extraordinary plasticity of HCV quasispecies, which underwent rapid evolution to tupaia-tropic variants as early as 24 h after infection. It was also shown that HCV could activate interferon-sensitive genes, albeit modestly in comparison with other viruses such as Semliki Forest virus. Importantly, HCV activated NF-κB in primary hepatocytes and upregulated NF-κB-responsive genes including the chemokines MCP-1 and CXCL2 (MIP-2). This effect may play a role in induction of the hepatic inflammatory reaction in vivo. In summary, HCV quasispecies adapt rapidly to the specific biology of the host and HCV stimulates a blunted interferon response while inducing a proinflammatory phenotype in the infected cell.

Viral evolution of hepatitis C in injection drug users

Injection drug users represent the largest cohort of patients with established hepatitis C virus (HCV) infection as well as the group that is at highest risk for new infections. Most published studies have focused on the clinical consequences of established HCV infection and have not examined the consequences of new infection. The aim of the current study was to measure the virological consequences of HCV in patients with ongoing injection drug use that might pose a risk for new and/or for superinfection with additional strains of HCV. We examined the following groups: (a) those with resolved HCV infection with ongoing injection drug use, (b) those with chronic infection who continued to inject and (c) those with chronic infection who no longer injected. Our study demonstrated a spectrum of responses. The majority of patients appeared to be 'protected' from new infection. None of six patients with resolved infection had detectable HCV RNA by quantitative or qualitative PCR when followed for 1 year. Similarly, despite ongoing injection drug use, no patient with persistent infection had a 'switch' in HCV genotype indicative of possible superinfection. Virological analysis of HCV quasispecies to detect possible infection with new variants of HCV in patients with apparently 'stable' infection, indicated divergence of virus over time, divergence that was unrelated to injection drug behaviour. Thus, patients with ongoing or prior HCV infection appear to develop immunity that protects against further infection with HCV despite repeated exposure.

Management of hepatitis C virus infection in the setting of liver transplantation

1. Posttransplantation recurrence of hepatitis C virus infection is a universal phenomenon with a highly variable natural history. 2. Approximately 10% to 25% of hepatitis C virus- infected recipients of liver allografts will develop cirrhosis within 5 years' after transplantation. 3. The 1-year actuarial risk of hepatic decompensation after recurrence of cirrhosis approximates 42%. 4. Some of the factors associated with aggressive recurrence include donor and recipient age, recent year of transplantation, recipient gender and race, the use of antithymocyte globulin, and high dose of corticosteroids. 5. Highly aggressive recurrent hepatitis C virus infection leading to cirrhosis fares poorly after retransplantation in the presence of hyperbilirubinemia and renal failure, with a 1-year survival of approximately 40%. 6. Elevated serum aminotransferases are a poor indicator or recurrent disease. 7. Current sustained virological response after combination pegylated alpha interferon and ribavirin treatment is approximately 25%. 8. There is no consensus on initiation time point, duration of treatment, or dosage. Given immunosuppression, at least 48 weeks of therapy is a reasonable approach. 9. Treatment for 48 weeks is cost effective. Incremental cost-effectiveness ratio for men aged 55 years is $29,100 per life-year saved.

Natural history of hepatitis C following liver transplantation

PURPOSE OF REVIEW

Currently, chronic hepatitis C virus-infection-related cirrhosis is the most common indication for liver transplantation in the USA and most parts of the world. While the incidence of new hepatitis C virus cases has decreased, the prevalence of infection will not peak until the year 2040. In addition, as the duration of infection increases, the proportion of new patients with cirrhosis will double by 2020 in an untreated patient population. If this model is correct, the projected increase in the need for liver transplantation secondary to chronic hepatitis C virus infection will place an impossible burden on an already limited supply of organs. In this article we present a comprehensive review of post-transplant hepatitis C virus infection and address the major challenges that face the transplant community.

RECENT FINDINGS

Hepatitis C virus infection recurs virtually in every post-transplant patient. Typically, serum levels of hepatitis C virus RNA increase rapidly from week 2 post-liver transplant, achieving 1-year post-liver transplant levels that are 10-20-fold greater than the mean pre-liver transplant levels. Progression of chronic hepatitis C virus is more aggressive after liver transplantation with a cumulative probability of developing graft cirrhosis estimated to reach 30% at 5 years. Approximately 10% of the patients with recurrent disease will die or require re-transplantation within 5 years post-transplantation. Interventions to prevent, improve, or halt the recurrence of hepatitis C virus infection have been evaluated by multiple small studies worldwide with similar overall rates of virological clearance of approximately 9-30%. Current consensus recommends combination therapy with pegylated interferon and ribavirin for those patients with histological recurrence of hepatitis C virus infection and fibrosis of >/= 2/4. Therapy is adjusted to tolerance and rescued with granulocyte colony-stimulating factor and erythropoietin for bone marrow suppression.

SUMMARY

The major challenges that face the transplant community in the coming years include new strategies to meet the growing demand for limited organ donor supplies and improvement of treatment for those patients in whom recurrence of viral disease has occurred. Only with improved antiviral treatments and strategies will we make a significant impact on this problem.

Evolution of hepatitis C virus quasispecies immediately following liver transplantation

Liver cirrhosis caused by chronic hepatitis C virus (HCV) infection is the main indication for liver transplantation (LT). There is little information on HCV genetic evolution following transplantation. The aim of this study was to carefully assess early evolution of HCV quasispecies in a cohort of 18 liver transplant recipients followed prospectively. Quasispecies analysis was performed by sequence analysis of the hypervariable region 1 (HVR1) before transplantation and at day 4 and week 4 following LT. A predominant variant was present in 12 (67%) of the 18 patients before transplantation and the same variant was propagated and remained predominant after LT in 6 (50%) of these patients. In the remaining individuals, there were major changes in the quasispecies composition, mostly occurring during the first days after LT. There was a progressive decrease in the nonsynonymous (dN)/synonymous (dS) ratios from baseline (1.2) to day 4 (.6) (P = .08) and to week 4 after LT (.3) (P = .015). Similarly, genetic distance (GD) declined from baseline (.1) to day 4 (.03) (P = .07) and to week 4 (.04) (P = .04). We did not find any differences in HCV genetic evolution between patients with mild (n = 10) or severe (n = 8) disease recurrence. In conclusion, during the first days following transplantation, HCV quasispecies becomes more homogenous, even after major changes in its composition. Importantly, these changes persist and even increase during the 1st month after transplantation. The "bottleneck" effect caused by the implantation of a new graft and the lack of selective pressure due to the strong immunosuppression most likely explain this particular pattern of genetic evolution.

Molecular biology and clinical implication of hepatitis C virus

Hepatitis C virus (HCV) was first described in 1989 as the putative viral agent of non-A non-B hepatitis. It is a member of the Flaviviridae family and has been recognized as the major causative agent of chronic liver disease, including chronic active hepatitis, cirrhosis and hepatocellular carcinoma. HCV is a positive RNA virus with a genome containing approximately 9500 nucleotides. It has an open reading frame that encodes a large polyprotein of about 3000 amino acids and is characterized by extensive genetic diversity. HCV has been classified into at least 6 major genotypes with many subtypes and circulates within an infected individual as a number of closely related but distinct variants known as quasispecies. This article reviews aspects of the molecular biology of HCV and their clinical implication.

Genetic variability of hepatitis C virus NS3 protein in human leukocyte antigen-A2 liver transplant recipients with recurrent hepatitis C

The association between the severity of chronic hepatitis C and the variability of the hepatitis C virus (HCV) genome remains controversial, but to our knowledge few data are available to date regarding T-cell epitope coding regions in transplant patients. In the current study, we identified 21 human leukocyte antigen (HLA)-A2-positive Spanish patients with chronic hepatitis C, 14 immunosuppressed liver transplant recipients, and 7 immunocompetent controls. Alanine aminotransferase, aspartate aminotransferase, viral load, and rate of fibrosis progression were determined. Genetic distances of HCV isolates and variations in epitopes of the HCV nonstructural 3 protein (NS3-1393 LIFCHSKKK and NS3-1406 KLVALGINAV) were compared between patients with slow or fast progression of fibrosis. Isolates from transplant patients with fast progression were found to be more divergent (P =.03), had a higher mean value of synonymous (dS) variations (P =.02), and some were differentiated in a phylogenetic tree, compared with isolates from patients with slow progression. The HLA-A2-restricted NS3-1406 epitope was found to be more variable (20 of 21 isolates differed from the prototype) compared with the A3-restricted NS3-1392 epitope (19% vs. 1.25% variation). A shift in the viral peptide was not detected in a subset of transplant patients, but was evident in two of three nontransplant patients with follow-up. There was no correlation noted between a particular amino acid variation and fibrosis progression (slow or fast) in either transplant or nontransplant patients. The results of the current study suggest that 1) there may be different HCV-1b strains in our geographic area, 2) immunosuppression appears to have little effect in amino acid variation at the HCV NS3-1406 epitope, and 3) variations over time might be more frequent in nonimmunosuppressed patients.

Progression of liver fibrosis in patients with chronic hepatitis C after orthotopic liver transplantation

BACKGROUND

Hepatitis C virus (HCV)-related cirrhosis is the leading indication for orthotopic liver transplantation (OLTx). HCV recurrence is universal after OLTx, with a highly variable course. This study aimed to find factors that affect progression of fibrosis in recurrent HCV.

METHODS

Fifty-eight HCV patients underwent OLTx at our center who were selected on the basis of available preOLTx serum or explanted liver sample and liver biopsy obtained at least 6 months postOLTx. All liver biopsies were performed when clinically indicated and were scored using the modified Hepatitis Activity Index (HAI). Primary immunosuppression consisted of tacrolimus and prednisone.

RESULTS

The group included 41 males (mean age 49.6 years). HCV genotype distribution was 1a, 31 (53%); 1b, 16 (28%), and others 11 (19%). The mean follow-up was 53.1 months. Patients with genotype 1a (n=31; mean 46.3 months) had significantly lower fibrosis-free survival analyzed by the presence of fibrosis stages 5 and 6 when compared with other genotypes (n=27; mean 60.1 months; P=0.0088, log rank test). Mean HAI scores were significantly higher in HCV genotype 1a, although there were no differences in survival between genotypes. Similarly, patients with cytomegalovirus (CMV) infection postOLTx (n=4) had a higher fibrosis progression rate compared with those without CMV (n=54) (mean fibrosis-free survival 29.0 vs. 53.0 months P=0.0004, log-rank test). Human leukocyte antigen matching and rate of acute rejection did not influence progression of fibrosis.

CONCLUSION

Patients with HCV genotype 1a and those developing CMV postOLTx have a higher rate of hepatic fibrosis progression after OLTx for HCV-related chronic liver disease.

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

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

Controversies in the management of hepatitis C virus infection after liver transplantation

Recurrence of hepatitis C virus infection after liver transplantation is universal. A significant percentage of these patients develop progressive graft injury and cirrhosis. Those factors that modulate disease progression in liver transplant recipients with recurrent hepatitis C virus infection remain controversial and are poorly understood. Treatment of recurrent hepatitis C virus after liver transplantation with either interferon or interferon and ribavirin has yielded only limited success. Regardless of this, treatment is instituted. Peginterferon is more effective than standard interferon for treatment of chronic hepatitis C virus infection in the nontransplantation setting when used either alone or with ribavirin. The effectiveness of peginterferon, both with and without ribavirin in the posttransplantation setting, is currently being explored. In this review those factors thought to affect disease progression in patients with recurrent hepatitis C virus will be discussed, strategies that have been used to treat recurrent hepatitis C virus will be reviewed, and the impact that peginterferon may have on hepatitis C virus infection in the pretransplantation and posttransplantation setting will be explored.

Intrahepatic cholestasis after liver transplantation

Cholestasis is a common sequela of liver transplantation. Although the majority of cases remain subclinical, severe cholestasis may be associated with irreversible liver damage, requiring retransplantation. Therefore, it is essential that clinicians be able to identify and treat the syndromes associated with cholestasis. In this review, we consider causes of intrahepatic cholestasis. These may be categorized by time of occurrence, namely, within 6 months of liver transplantation (early) and thereafter (late), although there may be an overlap in their causes. The causes of intrahepatic cholestasis include ischemia/reperfusion injury, bacterial infection, acute cellular rejection, cytomegalovirus infection, small-for-size graft, drugs for hepatotoxicity, intrahepatic biliary strictures, chronic rejection, hepatic artery thrombosis, ABO blood group incompatibility, and recurrent disease. The mechanisms of cholestasis in each category and the clinical presentation, diagnosis, treatment, and outcome are discussed in detail.

Natural history of hepatitis C and outcomes following liver transplantation

Hepatitis C-associated liver failure is the most common indication for liver transplantation and the infection recurs nearly universally following transplantation. Histologic evidence of recurrence is apparent in approximately 50% of HCV-infected recipients in the first postoperative year. Approximately 10% of HCV-infected recipients will die or lose their allograft secondary to hepatitis C-associated allograft failure in the medium term. HCV-infected recipients who undergo retransplantation experience 5-year patient and graft survival rates that are similar to recipients undergoing retransplantation who are not HCV-infected. While the choice of calcineurin inhibitor or the use of azathioprine have not been clearly shown to affect histologic recurrence of hepatitis C or the frequency of rejection in HCV-infected recipients, cumulative exposure to corticosteroids is associated with increased mortality, higher levels of HCV viremia, and more severe histologic recurrence. In contrast to non-HCV-infected recipients, treatment for acute cellular rejection is associated with attenuated patient survival among recipients with hepatitis C. The development of steroid-resistant rejection is associated with a greater than 5-fold increased risk of mortality in HCV-infected liver transplant recipients. In lieu of large studies in a posttransplant population, therapy with pegylated IFN (+/- ribavirin) should be considered in recipients with histologically apparent recurrence of hepatitis C before total bilirubin exceeds 3 mg/dl. The role of hepatitis C immunoglobulin and new immunosuppression agents in the management of posttransplant hepatitis C infection is still evolving.

Evolution of hepatitis C virus quasispecies in renal transplant patients with de novo glomerulonephritis

Long-term renal allograft survival in kidney transplant recipients infected by hepatitis C virus (HCV) may be influenced by the occurrence of de novo glomerulopathy associated with this virus. Therefore, we studied the evolution of HCV quasispecies in kidney transplant recipients infected by HCV with or without de novo glomerulopathy. The hypervariable region 1 (HVR-1) of the virus envelope was analyzed by cloning and sequencing 20 clones per sample to assess complexity and diversity from six kidney transplant patients who developed de novo glomerulopathy (group I) matched to six kidney transplant recipients without glomerular disease (group II), according to age, time since renal transplantation, and HCV genotype. Two sera were analyzed for each patient: one at the time of renal transplantation and the other at the time of appearance of de novo glomerulopathy, or after a similar duration since transplantation in group II. Overall, there was a significant increase of HCV viremia after the transplantation. This increase did not differ significantly between group I (+0.5 log copies/ml) and group II patients (+1 log copies/ml). The intersample diversity of HCV was similar in the two groups. Complexity and viral diversity were also similar at the time of transplantation. By contrast, complexity, diversity, and the proportion of nonsynonymous substitutions per nonsynonymous site were significantly higher after transplantation in group I patients. Our findings suggest a higher immune response and/or a particular cytokine production in patients developing de novo glomerulopathy rather than a direct effect of HCV on renal cells.

Hepatitis C virus in the human liver transplantation model

Hepatitis C virus-related liver failure is the single leading indication for liver transplantation, and the study of HCV in the transplant setting has enhanced the understanding of the natural history of disease and putative mechanisms by which HCV causes liver injury. In a subset of patients, allograft cirrhosis develops within a few years after transplantation, and recent findings suggest these individuals are immunologically impaired compared with individuals with mild HCV recurrence at long-term follow-up. Fig. 9 shows a conceptual paradigm of mechanisms potentially involved in shaping HCV outcome after transplantation. It is possible that relative antiviral control by innate and adaptive immune responses (to maintain HCV replication below a certain threshold) prevents direct cytopathic injury and induction of oxidative stress and apoptosis of cells. Additional phenomena that may contribute to induction of apoptosis (eg, genetic polymorphisms within the donor organ. CMV coinfection, and ischemic-preservation injury) may augment the initial cascade of liver injury. Recruitment to the allograft of nonspecific cells may decrease viral replication by way of noncytolytic mechanisms or augment viral replication (eg, Th2 phenotype) and direct cytopathic injury. The immune response is likely insufficiently vigorous to keep viral replication under control, but may maintain chronic liver injury. The liver transplant model is unique in that distinct phenotypic outcomes can be observed over a short period of time. A consideration of the temporal evolution of different mechanisms is also important, because mechanisms that initially predominate may become less important over time, and conversely, as suggested with the inverse correlation between viral load at 5 years and allograft fibrosis, new immune responses may emerge that modify the host-virus interaction. Prospective characterization of the immunoregulatory and virologic mechanisms involved in the liver transplantation model hopefully will help unravel the causal basis of reported associations, lead to the development of highly specific therapeutic strategies, and ultimately diminish the rate of graft loss from recurrent disease.

Evolution of hepatitis C viral quasispecies after liver transplantation

BACKGROUND & AIMS

To determine whether HCV quasispecies diversity correlated positively with liver disease progression after orthotopic liver transplantation (OLT).

METHODS

We studied 11 patients undergoing OLT for HCV-related cirrhosis with recurrent hepatitis C in 2 groups according to the stage of hepatic fibrosis on follow-up. The mild group had stage 1 or 2 fibrosis; the severe group, stage 3 or 4 fibrosis. HCV quasispecies diversity was assessed by cloning and sequencing in pretransplantation and posttransplantation serum samples.

RESULTS

In the mild fibrosis group, intrasample hypervariable region 1 (HVR1) genetic distance and nonsynonymous substitutions increased after OLT, whereas in the severe fibrosis group, these parameters decreased in follow-up. In contrast, intrasample diversity progressed similarly in both groups in the adjacent sequences flanking HVR1. There was an inverse correlation between the stage of hepatic fibrosis and amino acid complexity after OLT. Among all patients, the estimated rate of amino acid change was greater initially and became more constant after 36 months.

CONCLUSIONS

After OLT, a more complex HCV HVR1 quasispecies population was associated with mild disease recurrence. Among those patients with severe recurrent hepatitis C, HCV appeared to be under greater immune pressure. The greatest change in viral amino acid sequences occurred in the first 36 months after OLT.

Pathogenesis of hepatitis C virus recurrence in the liver allograft

1. Hepatitis C virus (HCV) infection in the allograft occurs in the setting of greater viral burden than in nontransplantation patients. 2. Infection of the allograft occurs early (within days and possibly during the intraoperative reperfusion phase). 3. Viral burden plateaus at 1 month posttransplantation and (in the absence of cholestatic HCV) peaks at the time of acute hepatitis (1 to 4 months). 4. Acute hepatitis is associated with immune cell infiltration and hepatocyte apoptosis. 5. Cholestatic HCV seems to be a disease of direct HCV cytopathic injury in the setting of extreme virus levels, an intrahepatic T helper subtype 2 cell (T(H)2)-like response, and lack of a specific HCV-directed response. 6. Chronic hepatitic HCV seems to behave at the molecular and/or cellular level in a similar fashion to the nontransplantation setting, with activation of T(H)1 inflammatory, profibrotic, and proapoptotic pathways. This process operates at a greater viral burden than pretransplantation and leads to more progressive disease. 7. More studies are required to examine and distinguish allograft rejection in the setting of HCV infection from HCV infection alone.

A longitudinal analysis of T-cell epitope-coding regions of hepatitis C virus after liver transplantation

BACKGROUND

Hepatitis C virus (HCV)-related liver failure is the single leading indication for orthotopic liver transplantation (OLT) worldwide. The mechanisms that underlie the observed differences in natural history of HCV recurrence remain poorly understood. We have previously demonstrated that differential T-cell responses correlate with histologic severity after OLT. We hypothesized that amino acid substitutions within critical T-cell epitopes could lead to increased severity of HCV disease.

METHODS

We determined the peptide sequences from sequential serum-derived viral RNA by reverse transcription and direct polymerase chain reaction sequence analysis from 32 HCV genotype 1-infected patients with well-characterized outcomes after liver transplantation. Serum samples were analyzed for HCV sequence the day of OLT and at least one time point post-OLT. To construct evolutionary relationships among the different patient samples, phylogenetic analyses of core and NS3 sequences were performed using a matrix fed into a neighbor-joining tree algorithm.

RESULTS

The phylogenetic analyses revealed remarkable conservation within a given individual and no significant differences when comparing patients with severe versus mild recurrence. Accordingly, the synonymous mutation rate was consistently greater than the nonsynonymous substitution rate. The nine epitopic regions analyzed were also preserved so that, with the exception of one patient with mild recurrence, none of the patients demonstrated a shift in viral peptide sequence.

CONCLUSIONS

HCV core and NS3 viral peptide sequences are identical before and after OLT in most patients, suggesting that the prevalent sequence is preserved in most cases, and viral variants are competent to establish infection after OLT. Although these results do not support viral mutation as a dominant pathogenic mechanism after OLT, other viral regions need to be analyzed.

Intrahepatic cytokine profiles associated with posttransplantation hepatitis C virus-related liver injury

Recurrent chronic hepatitis, cholestatic hepatitis, and acute rejection in conjunction with hepatitis C virus (HCV) recurrence are well-recognized clinical sequelae of reinfection of the hepatic allograft with HCV. The aim of this study is to characterize intrahepatic cytokine responses associated with reinfection of the allograft with HCV in these settings. Intrahepatic messenger RNA expression of T helper cell subtype 1 (TH1) cytokines interleukin-2 (IL-2), interferon-gamma, and tumor necrosis factor-alpha and TH2 cytokines IL-4 and IL-10 was measured by real-time polymerase chain reaction system using TaqMan probes in 53 liver specimens from six groups of patients. These were: (1) recurrent chronic hepatitis C (CH-I; n = 15), (2) cholestatic hepatitis (n = 6), (3) acute rejection associated with HCV recurrence (AR-HCV; n = 12), (4) acute rejection in non-HCV-infected allografts (AR non-HCV; n = 5), (5) patients with chronic hepatitis C who did not undergo transplantation (CH-C; n = 10), and (6) non-diseased liver tissue (n = 6). Intrahepatic viral loads were measured using an Amplicor monitor assay (Roche Diagnostic Systems, Branchburg, NJ). The CH-I and CH-C groups had similar TH1 intrahepatic cytokine profiles. Compared with the CH-I group, the cholestatic group expressed increased levels of the TH2 cytokines IL-10 (P =.024) and IL-4 (P =.0024). The AR-HCV group also expressed more TH2 cytokines IL-10 (P =.014) and IL-4 (P =.034) compared with the CH-I group. Both the AR-HCV and AR non-HCV groups showed similar intrahepatic cytokine profiles. Intrahepatic viral loads were highest in the cholestatic group compared with the AR-HCV, CH-I, and CH-C groups (P =.0007). In conclusion, a novel observation is that the cholestatic group showed upregulation of the TH2 cytokines IL-10 and IL-4, in addition to high viral loads. In this setting, the TH2 immune response may favor viral replication and graft damage.

Impact of the recurrence of hepatitis C virus infection after liver transplantation on the long-term viability of the graft

BACKGROUND

The impact of hepatitis C virus (HCV) infection recurrence after orthotopic liver transplantation (OLT) on graft viability is still not accurately defined. Our study aims to evaluate the magnitude and rate of progression of HCV-induced liver damage after OLT in a single institution cohort of 122 HCV-infected recipients.

METHODS

All patients transplanted at our institution between 1988 and 1996 with positive serum HCV antibodies before OLT, minimum postoperative survival of 6 months, and without hepatitis B virus coinfection or severe non-HCV-related graft complications were retrospectively included in the study.

RESULTS

HCV infection recurrence was almost universal, and genotype 1b was observed in 87% of the cases. After a median histological follow-up of 43 months (range: 7-96), evidences of HCV-induced histological damage were found in 94% of the cases. The actuarial rates of severe graft damage (including cirrhosis, fibrosing cholestatic hepatitis, and submassive liver necrosis) were 15%, 33%, and 44% at 3, 5, and 7 years, respectively, and among these patients, 52% developed decompensated liver disease during the follow-up and 36% lost their grafts. The biochemical severity at the onset of the recurrent hepatitis and the development of cholestasis or cytomegalovirus disease were independent predictors of severe HCV-related graft damage. No differences were found in graft and patient survival when positive-HCV OLT recipients were compared with a coetaneous cohort of 215 non-HCV OLT recipients.

CONCLUSIONS

HCV infection recurrence leads to severe liver damage and subsequently to clinical decompensation in a significant proportion of OLT recipients. Some clinical and biochemical characteristics can predict the severity of HCV-induced graft damage.

Hepatitis C virus and liver transplantation

Advances in immunosuppressive therapy, operative techniques, and perioperative management have resulted in long-term patient survival rates approaching 90% following liver transplantation for chronic viral hepatitis. The increasing number of referrals for liver transplantation reflects the impact of chronic HCV infection as a cause of end-stage liver disease. Unlike hepatitis B, there is still no effective treatment in preventing recurrent hepatitis C after liver transplantation. The spectrum of allograft injury related to universal HCV infection recurrence ranges from no evidence of histologic injury to mild inflammation to severe disease with allograft failure in small proportion of patients. Various factors may explain these differing outcomes, including degree of pretransplantation viremia, HLA compatibility, presence of more pathogenic HCV genotypes, integrity of cellular immune response, and type of immunosuppression. Fortunately, patient survival does not seem to be affected short-term; the long-term outcome of liver transplantation for chronic hepatitis C is unclear but is likely to be decreased. Combination therapy with interferon plus ribavirin seems to be a promising treatment strategy for posttransplantation recurrent hepatitis C, and the use of pegylated interferon plus ribavirin may improve these results. Patients with moderate to severe allograft hepatitis are appropriate candidates for combination antiviral therapy. Histopathologically documented recurrent hepatitis C in liver transplant recipients is associated with impaired quality of life, inferior physical condition, and a higher incidence of depression compared with patients who did not have HCV and in those without HCV recurrence. In conclusion, it is possible that the continued improvements in antiviral therapy against HCV infection may ultimately decrease the number of patients needing liver transplantation. Suitable candidates with chronic HCV infection thus warrant treatment with pegylated interferon plus ribavirin combination therapy in the hope of decreasing disease progression. Recent studies, which require confirmation, suggest that nonresponders to standard antiviral therapy may benefit from maintenance therapy. The donor pool for patients with chronic hepatitis C and decompensated cirrhosis can be improved by using HCV-positive donors and by increasing utilization of newer surgical techniques, including adult-to-adult living-donor liver transplantation and split-liver transplantation.