Liver transplantation with hepatitis C virus-infected graft: interaction between donor and recipient viral strains

Viruses, cancer and non-self recognition

Virus-host interactions form an essential part of every aspect of life, and this review is aimed at looking at the balance between the host and persistent viruses with a focus on the immune system. The virus-host interaction is like a cat-and-mouse game and viruses have developed ingenious mechanisms to manipulate cellular pathways, most notably the major histocompatibility (MHC) class I pathway, to reside within infected cell while evading detection and destruction by the immune system. However, some of the signals sensing and responding to viral infection are derived from viruses and the fact that certain viruses can prevent the infection of others, highlights a more complex coexistence between the host and the viral microbiota. Viral immune evasion strategies also illustrate that processes whereby cells detect and present non-self genetic material to the immune system are interlinked with other cellular pathways. Immune evasion is a target also for cancer cells and a more detailed look at the interfaces between viral factors and components of the MHC class I peptide-loading complex indicates that these interfaces are also targets for cancer mutations. In terms of the immune checkpoint, however, viral and cancer strategies appear different.

Successful Kidney Transplantation in a Recipient Coinfected with Hepatitis C Genotype 2 and HIV from a Donor Infected with Hepatitis C Genotype 1 in the Direct-Acting Antiviral Era

Despite significant advances in transplantation of HIV-infected individuals, little is known about HIV coinfected patients with hepatitis C virus (HCV) genotypes other than genotype 1, especially when receiving HCV-infected organs with a different genotype. We describe the first case of kidney transplantation in a man coinfected with hepatitis C and HIV in our state. To our knowledge, this is also the first report of an HIV/HCV/HBV tri-infected patient with non-1 (2a) HCV genotype who received an HCV-infected kidney graft with the discordant genotype (1a), to which he converted after transplant. Our case study highlights the following: (1) transplant centers need to monitor wait times for an HCV-infected organ and regularly assess the risk of delaying HCV antiviral treatment for HCV-infected transplant candidates in anticipation of the transplant from an HCV-infected donor; (2) closer monitoring of tacrolimus levels during the early phases of anti-HCV protease inhibitor introduction and discontinuation may be indicated; (3) donor genotype transmission can occur; (4) HIV/HCV coinfected transplant candidates require a holistic approach with emphasis on the cardiovascular risk profile and low threshold for cardiac catheterization as part of their pretransplant evaluation.

Hepatitis C genotype change after transplantation utilizing hepatitis C positive donor organs

A shortage in organs for transplantation has led to the increased use of hepatitis C (HCV) infected donor organs for solid organ transplant recipients infected with HCV. However, the donor HCV genotype is not routinely checked or known prior to transplant. Here, we report 4 cases of genotype conversion after transplantation in patients receiving HCV infected donor organs. This change in genotype may potentially impact HCV progression as well as treatment choice for these patients.

Management of Chronic Hepatitis C in End-stage Renal Disease

Treatment for chronic viral hepatitis C has advanced dramatically to current standard of care all-oral direct-acting antiviral regimens with relatively short treatment duration and high efficacy. Patients with comorbid end-stage renal disease have constituted a "special patient population" with data and treatment options lagging behind that of the broader population of patients with chronic hepatitis C until recently. Herein we review the current evidence base for direct-acting antiviral therapy in this population. We provide a suggested algorithm for the evaluation of such patients for therapy. We highlight special considerations in regards to the choice of regimen, duration, and timing in regards to potential kidney transplantation.

The American Society of Transplantation Consensus Conference on the Use of Hepatitis C Viremic Donors in Solid Organ Transplantation

The availability of direct-acting antiviral agents for the treatment of hepatitis C virus (HCV) infection has resulted in a profound shift in the approach to the management of this infection. These changes have affected the practice of solid organ transplantation by altering the framework by which patients with end-stage organ disease are managed and receive organ transplants. The high level of safety and efficacy of these medications in patients with chronic HCV infection provides the opportunity to explore their use in the setting of transplanting organs from HCV-viremic patients into non-HCV-viremic recipients. Because these organs are frequently discarded and typically come from younger donors, this approach has the potential to save lives on the solid organ transplant waitlist. Therefore, an urgent need exists for prospective research protocols that study the risk versus benefit of using organs for hepatitis C-infected donors. In response to this rapidly changing practice and the need for scientific study and consensus, the American Society of Transplantation convened a meeting of experts to review current data and develop the framework for the study of using HCV viremic organs in solid organ transplantation.

Pros and Cons: Usage of organs from donors infected with hepatitis C virus - Revision in the direct-acting antiviral era

Should organs from hepatitis C antibody positive donors (HCVD+) be used for transplantation? Organ shortage forces transplant teams to use donors with extended criteria. The decision to transplant a HCVD+ graft is a balance between the risk of transmission of a virus that could lead to end-stage liver diseases and the benefit of access to transplantation, specifically in patients with life-threatening disease. The other issue is the impact of HCV-related liver fibrosis in the donor graft on the long-term outcome in the recipient. Thus, the use of HCVD+ demonstrated a shorter meantime on the waiting list in kidney transplantation. When a HCVD+ graft is transplanted, the risk of HCV transmission depends on; 1) the quality of screening of the donor; 2) the presence of viral replication in the donor at the time of transplantation and the ability to detect it; and 3) the HCV status of the recipient but also the type of transplanted organ. In liver transplantation, the use of HCVD+ graft is usually restricted to recipients with a chronic HCV infection. Several reports showed some competition between HCV donor and recipient strain without deleterious impact on graft and patient survival. Controversies are still pending regarding the quality of the graft and the progression of fibrosis. The recent approval of direct-acting antiviral agents (DAA) dramatically changes the landscape of HCV infection treatment. After transplantation, combinations of DAA show high efficacy and good safety profile. In the near future, extensive use of DAA should reduce the number of HCVD+ with a positive HCV RNA, limiting the risk of transmission but also the number of patients on waiting lists for a disease related to HCV.

Quasispecies dynamics in hepatitis C liver transplant recipients receiving grafts from hepatitis C virus infected donors

The allocation of liver grafts from hepatitis C virus (HCV)-positive donors in HCV-infected liver transplant (LT) recipients leads to infection with two different viral populations. In a previous study, we examined quasispecies dynamics during reinfection by clonal sequencing, which did not allow an accurate characterization of coexistence and competition events. To overcome this limitation, here we used deep-sequencing analysis of a fragment of the HCV NS5B gene in six HCV-infected LT recipients who received HCV-infected grafts. Successive expansions and contractions of quasispecies complexity were observed, evolving in all cases towards a more homogeneous population. The population that became dominant was the one displaying the highest mutant spectrum complexity. In four patients, coexistence of minority mutants, derived from the donor or the recipient, were detected. In conclusion, our study shows that, during reinfection with a different HCV strain in LT recipients, the viral population with the highest diversity always becomes dominant.

Next-Generation Sequencing of 5' Untranslated Region of Hepatitis C Virus in Search of Minor Viral Variant in a Patient Who Revealed New Genotype While on Antiviral Treatment

The role of mixed infections with different hepatitis C virus (HCV) genotypes in viral persistence, treatment effects, and tissue tropism is unclear. Next-generation sequencing (NGS), which is suitable for analysis of large, genetically diverse populations offers unparalleled advantages for the study of mixed infections. The aim of the study was to determine, using two different deep sequencing strategies (pyrosequencing - 454 Life Sciences/Roche and reversible terminator sequencing-by-synthesis by Illumina), the origin of a novel HCV genotype transiently detectable during antiviral therapy (pre-existing minor population vs. de novo superinfection). Secondly, we compared 5' untranslated region (5'-UTR) variants obtained by the two NGS approaches. 5' UTR amplification products from 9 samples collected from genotype 1b infected patient before, during, and after treatment (4 serum and 5 peripheral blood mononuclear cell - PBMC - samples) were subjected to the next-generation sequencing. The sequencing revealed the presence of two (454/Roche) and one (Illumina) genotype 4 variants in PBMC at Week 16. None of these variants were present either in the preceding or following samples as revealed by both platforms. 454/Roche sequencing detected 24 different 5'-UTR variants: 8 were present in serum and PBMC, 4 only in serum and 12 only in PBMC. Illumina sequencing detected 11 different 5'-UTR variants: 5 in serum and PBMC, 4 only in serum and 2 only in PBMC. Six variants were identical for both sequencing platforms. The difference in variants number was primarily due to variability in two 5'-UTR homopolymeric regions. In conclusion, longitudinal analysis of HCV variants, employing two independent deep sequencing methods, suggests that the transient presence of a different genotype strain in PBMC was a result of superinfection and not a selection of pre-existing minor variant.

Force for ancient and recent life: viral and stem-loop RNA consortia promote life

Lytic viruses were thought to kill the most numerous host (i.e., kill the winner). But persisting viruses/defectives can also protect against viruses, especially in a ubiquitous virosphere. In 1991, Yarmolinsky et al. discovered the addiction modules of P1 phage, in which opposing toxic and protective functions stabilize persistence. Subsequently, I proposed that lytic and persisting cryptic virus also provide addiction modules that promote group identity. In eukaryotes (and the RNA world), a distinct RNA virus-host relationship exists. Retrovirurses/retroposons are major contributors to eukaryotic genomes. Eukaryotic complexity appears to be mostly mediated by regulatory complexity involving noncoding retroposon-derived RNA. RNA viruses evolve via quasispecies, which contain cooperating, minority, and even opposing RNA types. Quasispecies can also demonstrate group preclusion (e.g., hepatitis C). Stem-loop RNA domains are found in long terminal repeats (and viral RNA) and mediate viral regulation/identity. Thus, stem-loop RNAs may be ancestral regulators. I consider the RNA (ribozyme) world scenario from the perspective of addiction modules and cooperating quasispecies (i.e., subfunctional agents that establish group identity). Such an RNA collective resembles a "gang" but requires the simultaneous emergence of endonuclease, ligase, cooperative catalysis, group identity, and history markers (RNA). I call such a collective a gangen (pathway to gang) needed for life to emerge.

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.

Living donor liver transplantation from a donor previously treated with interferon for hepatitis C virus: a case report

Introduction

Selecting a marginal donor in liver transplantation (LT) remains controversial but is necessary because of the small number of available donors.

Case presentation

A 46-year-old Japanese woman was a candidate to donate her liver to her brother, who had decompensated liver cirrhosis of unknown origin. Eight years before the donation, she had a mild liver dysfunction that was diagnosed as a hepatitis C virus (HCV) infection (serotype 2). She had received anti-viral therapy with interferon α-2b three times weekly for 24 weeks and had a sustained viral response (SVR). A biopsy of her liver before the donation showed normal findings without any active hepatitis, and her serum was negative for HCV-RNA. Only 67 patients have undergone LT from a cadaveric donor in Japan. The family in this case decided to have living donor LT. A careful selection for the liver graft donation was made; however, since she was the only candidate, we approved her as a living donor. She was discharged nine days after the liver donation. Her liver function recovered immediately. A computed tomography scan showed sufficient liver regeneration one year later. Her brother also had good liver function after LT and had no HCV infection 48 months after surgery and no de novo malignancy. Neither of the siblings has developed an HCV infection.

Conclusions

A patient with SVR status after interferon therapy might be considered a candidate for living donor LT but only if there are no other possibilities of LT for the recipient. A careful follow-up of the donor after donation is needed. The recipient also must have a very close follow-up because it is difficult to predict what might happen to the graft with post-transplant immunosuppression.

Long-term follow-up and outcome of liver transplantation from anti-hepatitis C virus-positive donors: a European multicentric case-control study

BACKGROUND

The growing prevalence of hepatitis C virus (HCV) infection in the general population has resulted in an increased frequency of potential organ donors that carry the virus. Given the significant disparity between organ supply and demand for transplantation, it becomes essential to consider whether livers from anti-HCV-positive donors may be considered suitable for transplantation.

METHODS

Based on a multicenter European database, 694 patients with HCV-related cirrhosis underwent liver transplantation and 11% of them received the graft from anti-HCV-positive donors. Of this group, we selected 63 patients (study group) and, after a 1:1 case-control approach, compared them with 63 patients that received an anti-HCV-negative donor graft (control group). Only grafts with preperfusion liver biopsy results with a fibrosis score of not more than 1 were used for transplantation.

RESULTS

Patients who received anti-HCV-positive grafts had a cumulative survival rate of 83.6% and 61.7% at 1 and 5 years, respectively, vs. 95.1% and 68.2% for the control group. In comparing overall patient and graft survival, there was no statistically significant difference between the two groups (P=0.22 and 0.11). Recurrence of hepatitis C tended to be more rapid in the group of patients who received anti-HCV-positive grafts, although it did not reach statistical significance (P=0.07).

CONCLUSIONS

We do not recommend the indiscriminate use of anti-HCV-positive donors, especially if HCV-RNA positive, as the use of this kind of graft could be linked to an advanced stage of fibrosis, the main risk factor we observed for earlier hepatitis C recurrence.

HCV selection and HVR1 evolution in a chimpanzee chronically infected with HCV-1 over 12 years

AIM

To study hepatitis C virus (HCV) selection and hypervariable region-1 (HVR1) evolution in a chimpanzee chronically infected with HCV-1 over 12 years after inoculation with a human factor VIII concentrate contaminated with HCV.

METHODS

From the inoculum, the earliest chimpanzee plasma and 12 annual plasma samples, HCV fragments including HVR1 were amplified followed by cloning and sequencing.

RESULTS

Five HCV subtypes - 1a, 1b, 2a, 2b, 3a - and multiple 1a strains were identified in the inoculum. Two 1a strains were found in the earliest chimpanzee sample, while a single HCV-1 strain was detected in the 12 annual samples. None of the chimpanzee sequences were identical to those found in the inoculum. Over 12 years, HVR1 patterns changed irregularly, but a few patterns showed identical nucleotide or amino acid sequences. In the last three years, the variety of HVR1 patterns decreased, while the proportion of major patterns increased. These corresponded to a higher virus load and a lower number of amino acid substitutions. Simultaneously, the HVR1 sequences became more similar to the consensus sequence of the 1a subtype.

CONCLUSION

HCV selection was observed from the inoculum to the inoculated chimpanzee and from the early acute hepatitis to the persistent chronic infection. The selection occurred at three levels: among subtypes after transmission, among isolates during acute hepatitis and among quasispecies in chronic infection.

Progression of fibrosis during chronic hepatitis C is associated with rapid virus evolution

Hepatic fibrosis is the primary mediator of disease due to chronic infection with hepatitis C virus (HCV). HCV exists as a quasispecies in each infected individual, and longitudinal viral sequence changes may reveal viral dynamics and the selection pressures applied by the host immune system. Thus, we hypothesized that patterns of sequence change might reveal the immunopathogenesis of fibrosis progression. We tested this hypothesis by studying individuals enrolled in a prospective study of chronic HCV-related hepatic fibrosis with little or no fibrosis at first biopsy (stage 0 or 1) and a second planned liver biopsy sample obtained 4 years later. Serum was obtained from five individuals with fast progression (FP; defined as a >2-stage change between visits) and 10 carefully matched individuals with slow progression (SP; defined as a <2-stage change between visits). We sequenced multiple cloned hemigenomic cDNAs from each person spanning six genes (core through NS3). Phylogenetic analysis revealed temporal shifts in phylogenetic clustering over time, suggesting frequent quasispecies replacement rather than simple diversification. In addition, mixed infections were detected in three subjects, with coexistence in two subjects (one FP, one SP) of subtypes 1a and 1b throughout the 4-year biopsy interval. Subjects with FP had a higher rate of evolution than subjects with SP, with a preponderance of synonymous changes, suggesting purifying selection, except in hypervariable region 1, where positive selection pressure is frequently detected. Thus, in a small but carefully matched cohort we found evidence for rapid neutral evolution of HCV in persons with rapid progression of hepatic fibrosis, suggesting higher turnover of infected cells.

Should antihepatitis B virus core positive or antihepatitis C virus core positive subjects be accepted as organ donors for liver transplantation?

Since the introduction of liver transplantation as a routine surgical procedure for the treatment of end-stage liver disease, there has been an increasing gap between the number of available grafts and the number of patients on the waiting list. This has led transplant centers to expand the donor pool by different means. One of them has been the introduction of living donor liver transplantation. Other strategies include using less than optimal allografts from deceased donors, the so-called marginal donors, which include the use of grafts from older subjects, livers with moderate amounts of steatosis, or from donors with markers of past or current infection with hepatitis viruses who have absent or minimal liver biochemical or histologic injury. In this review, we will focus on the current use of allografts from donors with antihepatitis B core antibody and/or antibodies against hepatitis C virus in cadaveric and living donor liver transplantation.

Clinical and therapeutic implications of hepatitis C virus compartmentalization

BACKGROUND & AIMS

Blood mononuclear cells (BMCs) frequently are infected by hepatitis C virus (HCV) variants that are not found in plasma. The influence of this compartmentalization on the natural and therapeutic outcome of hepatitis C is unknown.

METHODS

We studied 119 patients with previously untreated chronic HCV infection. Sixty-five of these patients started first-line treatment with pegylated interferon-alfa and ribavirin after enrollment in the study. The internal ribosomal entry site (IRES) of HCV RNA was amplified and compared between plasma and BMCs by means of single-strand conformational polymorphism (SSCP) analysis, line-probe assay, and cloning sequencing.

RESULTS

The IRES SSCP patterns differed between plasma and BMCs in 54 (48%) of 113 assessable patients. Twenty-seven (24%) of these patients were co-infected by 2 HCV types or subtypes, only 1 of which was detectable in BMCs (n = 25) or in plasma (n = 2). SSCP-defined compartmentalization was more frequent in former drug users than in others (35/56 [60%] vs 19/56 [34%]; P < .01), and less frequent in patients with genotype 1 HCV in plasma (26/73 [24%] vs 28/40 [65%]; P < .01). The only variables that were independently predictive of a sustained virologic response were SSCP-defined compartmentalization (25/31 vs 10/32; P = .0001) and genotype 2 or 3 infection of BMCs (22/31 vs 8/34; P = .002).

CONCLUSIONS

A significant proportion of patients with hepatitis C are co-infected by 2 or more HCV variants with distinct IRES sequences and distinct cellular tropism. This compartmentalization is a strong independent predictor of treatment efficacy.

Selective transmission of hepatitis C virus genotypes and quasispecies in humans and experimentally infected chimpanzees

This study determined whether selective transmission of hepatitis C virus (HCV) species occurred among human and chimpanzee recipients of contaminated blood products or plasma containing multiple genotypes, subgenotypes and quasispecies. Commercially prepared factor VIII concentrate (lot DO56), produced prior to HCV testing and inactivation, was subsequently found by direct cloning to contain the following subgenotypes: 1a and 1b (73 % of clones), 2a (13 % of clones), 2b (11 % of clones) and 3a (4 % of clones). A patient transfused with factor VIII concentrate DO56 was diagnosed with clinical non-A, non-B hepatitis and subsequently found to be infected with HCV subgenotype 1b. Among five chimpanzees inoculated experimentally with the same factor VIII concentrate, two were infected only with HCV subgenotype 1a and three were infected with approximately equivalent clonal proportions of subgenotypes 1a and 1b. HCV hypervariable region 1 (HVR1) quasispecies analysis of the DO56 factor VIII concentrate and a serum specimen from the single chimpanzee that developed a chronic HCV infection following inoculation with DO56 showed 0-56 % nucleotide variation. However, specimens from chimpanzees infected in the second to fourth passages of the DO56 inoculum had 0-8 % HVR1 quasispecies nucleotide variation. The high HVR1 quasispecies variation in the factor VIII concentrate and its first passage in chimpanzees indicates the presence of multiple HCV isolates, whereas the low variation in the second to fourth chimpanzee passages suggests transmission of a single HCV isolate. These findings strongly suggest selective transmission of HCV isolates during experimental chimpanzee infection and among humans exposed to multiple HCV species.

Heart transplantation using donors positive for hepatitis

From May 1994 to September 2003, 177 hearts were procured for heart transplantation (HTx) from donors ranging in age from 1 year 2 months to 66 years 5 months (mean = 30 years). All donors and recipients received serologic tests for hepatitis B surface antigen (HBsAg) and antibody (anti-HBs), and hepatitis C virus antibody (anti-HCV). Thirty-two donors were HBsAg-positive and another four were anti-HCV-positive. Two HBsAg-positive donors were transplanted to patients with no previous evidence of hepatitis. After HTx, one received hepatitis B immunoglobulin prophylaxis and no hepatitis was noted during a 5 years follow-up. The other seroconverted at 4 months after HTx, requiring lamivudine treatment. Another four HBsAg-positive donors were transplanted to HBsAg-positive recipients. All four recipients had hepatitis flare-ups requiring lamivudine treatment. The other 26 HBsAg-positive donors were transplanted to anti-HBs-positive recipients. None suffered from hepatitis. Among the four patients receiving anti-HCV-positive hearts, seroconversion was noted in one recipient at 26 months. This patient never had clinical hepatitis before he died of allograft rejection at 3 years after HTx. The other three recipients remain anti-HCV negative during follow-up of 80, 50, and 46 months. It was concluded the hepatitis B- or C-positive donors could be used as heart donors for status 1 patients. Donors with positive HBsAg may be transplanted to anti-HBs-positive recipients with no HBV infection.

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.