The natural history of recurrent hepatitis C and what influences this

Temporal association between increased virus-specific Th17 response and spontaneous recovery from recurrent hepatitis C in a liver transplant recipient

BACKGROUND

Spontaneous clearance of hepatitis C virus (HCV) after orthotopic liver transplantation (OLT) is a rare occurrence. Here, we present detailed immunological analysis of an interferon naive OLT recipient receiving uninterrupted immunosuppression who cleared HCV spontaneously 2 years after transplantation.

METHODS

Enzyme-linked immunospot assay analysis of peripheral T-cell interferon gamma (IFN-γ), interleukin (IL)-10, and IL-17 response to HCV core and nonstructural antigen 4 and enzyme-linked immunosorbent assay (ELISA) to collagen (Col) subtypes I, II, IV, and V were performed in the index patient at the time of viral clearance and compared with an OLT cohort with persistent viremia matched for time from OLT, immunosuppression, and histology. Enzyme-linked immunospot assay and ELISA analysis were repeated on the patient 4 years after OLT. Transcription-mediated amplification assays were used to confirm viral clearance.

RESULTS

Compared with a cohort of post-OLT and nontransplanted viremic HCV patients, the index patient with HCV clearance demonstrated higher IL-17, IL-10, and lower IFN-γ response to nonstructural antigen 4 and core antigen and a higher titer of antibodies (Abs) to Col subtypes I, II, and V during clearance. On follow-up 2 years later, HCV-specific IFN-γ was increased in the index patient, with a decline in IL-17 and IL-10 response and Col I, II, and V Ab titer.

CONCLUSIONS

Virus-induced activation of Th-17 cells may contribute to HCV clearance post-OLT. Maintenance of viral suppression may be facilitated by restoration of Th1 (IFN-γ) responses. Modulation of Th17 immunity deserves further attention as a therapeutic strategy in the treatment of HCV recurrence post-OLT.

Diabetes mellitus following liver transplantation in patients with hepatitis C virus: risks and consequences

Recurrent hepatitis C virus (HCV) infection of the allograft occurs universally following liver transplantation. Longitudinal natural history studies have identified several pre- and posttransplant factors associated with more rapid fibrosis progression, including baseline host and viral factors, donor factors and posttransplant immunosuppression effects, such as metabolic syndrome. Evidence accumulated over the past two decades indicates that HCV has metabolic associations, in particular insulin resistance and diabetes mellitus. Approximately half of HCV-positive liver transplant recipients develop posttransplant diabetes mellitus (PTDM), which is associated with accelerated fibrosis progression and poorer graft and patient survival outcomes. This review summarizes the risks and consequences of insulin resistance and PTDM in HCV-positive liver transplant recipients. Risk for developing PTDM is one factor that should be considered when choosing the primary immunosuppressive regimen following liver transplantation. Comparative studies suggest that cyclosporine A-based immunosuppression may provide improved responses to antiviral therapy and reduced incidence of PTDM compared with tacrolimus-based immunosuppression. Addressing insulin resistance and PTDM in HCV-positive liver transplant recipients may have the potential to slow HCV complications and improve survival outcomes.

Liver transplantation from hepatitis B surface antigen positive donors: a safe way to expand the donor pool

BACKGROUND & AIMS

The main limitation of orthotopic liver transplantation (OLT) is the scarcity of available donor organs. A possibility to increase the organ pool is to use grafts from hepatitis B virus surface antigen (HBsAg) positive donors, but few data are currently available in this setting. We assessed the clinical, serovirological, and immunological outcomes of liver transplant from HBsAg positive donors in a single centre study.

METHODS

From 2005 to 2009 10 patients underwent OLT from HBsAg positive donors, for HBV-related disease (n=6) or HBV-unrelated disease (n=4). The median follow-up was 42 months (range 12-60). All recipients were HBcAb positive and were given antiviral prophylaxis.

RESULTS

Patients transplanted for HBV-related disease never cleared HBsAg. Two HBsAg negative patients never tested positive for HBsAg, whereas the others experienced an HBsAg appearance, followed by spontaneous production of anti-HBs, allowing HBsAg clearance. No patient ever had any sign of HBV hepatitis. HBV replication was effectively controlled by antiviral therapy. The immunologic sub-study showed that a most robust anti-HBV specific T cell response was associated with the control of HBV infection.

CONCLUSIONS

OLT from HBsAg positive donors seems to be a safe procedure in the era of highly effective antiviral therapy.

Ultrasound-based transient elastography for the detection of hepatic fibrosis in patients with recurrent hepatitis C virus after liver transplantation: a systematic review and meta-analysis

Ultrasound-based transient elastography (TE) is a promising noninvasive alternative to liver biopsy for the detection of hepatic fibrosis due to recurrent hepatitis C virus (HCV) after liver transplantation (LT). However, its overall test performance in various settings remains unknown. The aim of this study was to perform a systematic review and diagnostic accuracy meta-analysis of studies comparing ultrasound-based TE to liver biopsy for the detection of hepatic fibrosis due to a recurrent HCV infection after LT. Electronic and manual bibliographic searches (including scientific abstracts) were performed to identify potential studies. A meta-analysis was conducted to generate pooled estimates of the sensitivity values, specificity values, likelihood ratios, and diagnostic odds ratios of individual studies. The extent of the heterogeneity and the reasons for it were assessed. Six fully published studies were identified for analysis. Five studies that evaluated significant fibrosis were identified. Among these studies, the pooled estimates were 83% for sensitivity [95% confidence interval (CI) = 77%-88%], 83% for specificity (95% CI = 77%-88%), 4.95 for the positive likelihood ratio (95% CI = 3.4-7.2), 0.17 for the negative likelihood ratio (95% CI = 0.09-0.35), and 30.5 for the diagnostic odds ratio (95% CI = 12.8-72.4). For the 5 studies that assessed cirrhosis, the pooled estimates were 98% for sensitivity (95% CI = 90%-100%), 84% for specificity (95% CI = 80%-88%), 7 for the positive likelihood ratio (95% CI = 2.8-17.3), 0.06 for the negative likelihood ratio (95% CI = 0.02-0.19), and 130 for the diagnostic odds ratio (95% CI = 36.5-462.1). A diagnostic threshold (or cutoff value) bias was identified as an important cause of heterogeneity for the pooled results of both patient groups. In conclusion, ultrasound-based TE has excellent diagnostic accuracy for identifying cirrhosis due to a recurrent HCV infection after LT. The detection of significant fibrosis is more accurate for these patients versus patients whose native liver is chronically infected with HCV.

Twelve-week posttreatment follow-up to predict sustained virologic response for recurrent hepatitis C infection in liver recipients

BACKGROUND

The current standard for determining sustained virologic response (SVR) in patients treated for hepatitis C virus (HCV) infection is undetectable serum HCV-RNA 24 weeks after treatment. This study evaluates the value of HCV-RNA determination at 12 weeks posttreatment (W+12) to predict SVR in liver transplant (LT) patients treated with pegylated interferon and ribavirin for recurrent HCV infection.

METHODS

This study, performed in 2001 to 2010, included HCV-LT patients with an end-of-treatment response (undetectable serum HCV-RNA) and HCV-RNA testing at 12 and 24 weeks posttreatment (W+12/W+24). HCV-RNA was detected with a qualitative polymerase chain reaction assay (detection limit 50 IU/mL) and, when positive, measured by quantitative PCR (detection limit 600 IU/mL) up to 2006. Since 2007, a real-time PCR-based test (detection limit 15 IU/mL) has been used. The positive predictive value (PPV) was defined as the probability that SVR would occur in patients with undetectable HCV-RNA at W+12 and W+24.

RESULTS

Of 162 patients treated during the study period, 57 (35%) had end-of-treatment response and were included. Of these, 45 (79%) had SVR and 12 (21%) had virologic relapse. At W+12, HCV-RNA was undetectable in 45 (79%) patients, all of whom had SVR, yielding a PPV for SVR at W+12 of 100% (95% confidence interval, 75.8%-100%).

CONCLUSIONS

Undetectable HCV-RNA at W+12 posttreatment has a high PPV for predicting SVR. HCV-RNA testing to assess SVR at this time point seems as valid as W+24 testing and could be considered for predicting SVR in HCV-LT patients receiving treatment with pegylated interferon and ribavirin.

Treatment of hepatitis C recurrence is less successful in female than in male liver transplant recipients

It has been recently suggested that the risk of graft loss after liver transplantation (LT) may increase in female HCV patients. The aim of the study was to examine gender differences in HCV therapy tolerance and outcome in LT patients treated for HCV recurrence. A retrospective study was conducted on liver recipients with HCV recurrence, who were given antiviral therapy from 2001 to 2009 in 12 transplant centers in Italy. Sustained virological response (SVR), adherence-to-therapy, and side effects were evaluated. A multivariate logistic regression model was used after adjusting for possible confounders. The data regarding 342 treated patients were analyzed. SVR was reported in 38.8% of patients. At baseline, male and female did not differ in HCV viral load, histology, or rate of diabetes. SVR was lower in females than in males (29.5% vs. 42.1%; P=0.03). Adherence-to-therapy was also lower in females than in males 43.4% vs. 23.8%; P=0.001); anemia was the main reason for lower adherence. In a multivariate analysis in patients Genotype1, female gender (P<0.04), early virological response (P<0.0001), and adherence to therapy (P<0.0001) were independent predictors for SVR. In conclusion, female gender represents an independent negative prognostic factor for the outcome of HCV antiviral therapy after LT.

Donor graft steatosis influences immunity to hepatitis C virus and allograft outcome after liver transplantation

BACKGROUND

Hepatitis C virus (HCV) recurrence after orthotopic liver transplantation (OLT) is universal, often with accelerated allograft fibrosis. Donor liver steatosis is frequently encountered and often associated with poor early postoperative outcome. The aim of this study was to test the hypothesis that allograft steatosis alters immune responses to HCV and self-antigens promoting allograft fibrosis.

METHODS

Forty-eight HCV OLT recipients (OLTr) were enrolled and classified based on amount of allograft macrovesicular steatosis at time of OLT. Group 1: no steatosis (0%-5% steatosis, n=21), group 2: mild (5%-35%, n=16), and group 3: moderate (>35%, n=11). Cells secreting interleukin (IL)-17, IL-10, and interferon gamma (IFN-γ) in response to HCV antigens were enumerated by Enzyme Linked Immunospot Assay. Serum cytokines were measured by Luminex, antibodies to Collagen I, II, III, IV, and V by ELISA.

RESULTS

OLTr of moderate steatotic grafts had the highest incidence of advanced fibrosis in protocol 1 year post-OLT biopsy (10.8% vs. 15.8% vs. 36.6%, r=0.157, P<0.05). OLTr from groups 2 and 3 had increased HCV-specific IL-17 (P<0.05) and IL-10 (P<0.05) with reduced IFN-γ (P<0.05) secreting cells when compared with group 1. This was associated with increase in serum IL-17, IL-10, IL-1β, IL-6, IL-5, and decreased IFN-γ. In addition, there was development of antibodies to Collagen I, II, III and V in OLTr with increased steatosis (P<0.05).

CONCLUSION

The results demonstrate that allograft steatosis influences post-OLT HCV-specific immune responses leading to an IL-17 T-helper response and activation of humoral immune responses to liver-associated self-antigens that may contribute to allograft fibrosis and poor outcome.

Immunosuppression, liver injury and post-transplant HCV recurrence

Hepatitis C virus (HCV) infection is a major cause for liver transplantation worldwide. Still, HCV re-infection of the graft occurs in almost all cases. Most liver transplant recipients experience episodes of graft hepatitis associated with fibrosis progression and graft failure. Clinical management of graft hepatitis can be challenging as in addition to rejection and HCV-induced hepatitis various other factors might be involved including toxic liver injury, steatohepatitis, ischaemic bile duct lesions or infections with other pathogens. Treatment options are often contradictory for different causes of graft hepatitis, and the role of distinct immunosuppressive drugs has been discussed controversially. Corticosteroids increase the infectivity of HCV by altering expression levels of entry factors and other immunosuppressive agents may have diverse effects on HCV replication and fibrosis progression. Interferon alpha-therapy of hepatitis C shows limited efficacy and tolerability in liver transplant recipients and may also cause rejection. In this review we summarize the current knowledge on mechanisms of liver injury in post-transplant hepatitis C, discuss the pros and cons of immunosuppressive agents in this specific setting and describe potential novel approaches to prevent HCV reinfection.

Long-term outcome of hepatitis C virus infections acquired after pediatric liver transplantation

The outcomes and characterization of hepatitis C virus (HCV) infections after pediatric liver transplantation (LT) have rarely been reported. We describe our experience with HCV infections after pediatric LT. Ten of 207 children (4.8%) who underwent LT at our institution (1985-2010) developed previously undiagnosed HCV disease. Eight received a liver graft before blood product and donor screening for HCV became available. The mean age at transplantation was 8.9 ± 4.3 years, and the median time from transplantation to the diagnosis of HCV was 15.1 years (range = 0.2-19.7 years). The genotypes were 1 (n = 8), 3 (n = 1), and undetermined (n = 1). At the time of this writing, all the patients were still alive with a mean follow-up of 7.3 ± 5.5 years after the diagnosis of HCV. Five patients did not receive treatment; 2 of these patients achieved spontaneous viral clearance (SVC). Four of the 5 treated patients achieved a sustained virological response, and 3 had an early virological response (EVR). Two of these 4 patients developed chronic rejection while they were on treatment, but this was resolved with a conversion from cyclosporine A to tacrolimus. The remaining patient was continuing treatment and had achieved EVR. In conclusion, despite the limitations of our series, de novo HCV infections after pediatric LT seem to have a slow histological progression. Even with genotype 1, the patients have a good long-term prognosis and respond well to treatment. Nevertheless, chronic rejection during antiviral therapy may develop. In addition, SVC may occur in this population.

Limiting hepatitis C virus progression in liver transplant recipients using sirolimus-based immunosuppression

Hepatitis C virus (HCV) causes progressive liver fibrosis in liver transplant recipients and is the principal cause of long-term allograft failure. The antifibrotic effects of sirolimus are seen in animal models but have not been described in liver transplant recipients. We reviewed 1274 liver recipients from 2002 to 2010 and identified a cohort of HCV recipients exposed to sirolimus as primary immunosuppression (SRL Cohort) and an HCV Control Group of recipients who had never received sirolimus. Yearly protocol biopsies were done recording fibrosis stage (METAVIR score) with biopsy compliance of >80% at both year one and two. In an intent-to-treat analysis, the SRL Cohort had significantly less advanced fibrosis (stage ≥2) compared to the HCV Control Group at year one (15.3% vs. 36.2%, p < 0.0001) and year two (30.1% vs. 50.5%, p = 0.001). Because sirolimus is sometimes discontinued for side effects, the SRL Cohort was subgroup stratified for sirolimus duration, showing progressively less fibrosis with longer sirolimus duration. Multivariate analysis demonstrated sirolimus as an independent predictor of minimal fibrosis at year one, and year two. This is the first study among liver transplant recipients with recurrent HCV to describe the positive impact of sirolimus in respect of reduced fibrosis extent and rate of progression.

Polymorphisms of toll-like receptors and their pathways in viral hepatitis

Toll-like receptors (TLRs) are an important part of the innate immune response to a variety of pathogens including hepatic viral infections. Activation of TLRs stimulates a complex intracellular signalling cascade that results in production of proinflammatory cytokines and interferons important for antiviral responses as well as induction of the adaptive arm of the immune system. There is substantial evidence for an important role for TLRs and TLR-mediated signalling in the pathogenesis and outcomes of hepatitis B and C in particular, but it might also influence responses to other viral hepatitis infections. Several single nucleotide polymorphisms (SNPs) of TLRs, relevant adaptor molecules and cytokines mediated by TLR signalling have been described that alter innate immune responses and have been implicated in a variety of human diseases including viral and other infections. There is now significant evidence that a number of TLR SNPs can affect various clinical outcomes in Caucasian patients with chronic HCV. However, the role of these polymorphisms in acute and other chronic hepatitis infections, including HBV as well as in non-Caucasian populations, has not been elucidated. In addition, results for SNPs downstream of TLR activation, such as in relevant cytokines, are inconsistent and their influence requires further investigation to determine the clinical significance of genetic variations in these mediators.

What is the long-term outcome of the liver allograft?

With improved long-term survival following liver transplantation (LT), issues relating to the assessment of the liver allograft in long-term survivors are becoming increasingly relevant. Histological abnormalities are commonly present in late post-transplant biopsies, including protocol biopsies from patients who appear to be well with good graft function. Recurrent disease is the commonest recognised cause of abnormal graft histology, but may be modified by the effects of immunosuppression or interactions with other graft complications, resulting in complex or atypical changes. Other abnormalities seen in late post-transplant biopsies include rejection (which often has different appearances to those seen in the post-transplant period), de novo disease, "idiopathic" post-transplant hepatitis (IPTH) and nodular regenerative hyperplasia. In many cases graft dysfunction has more than one cause and liver biopsy may help to identify the predominant cause of graft damage. Problems exist with the terminology used to describe less well understood patterns of graft injury, but there is emerging evidence to suggest that late rejection, de novo autoimmune hepatitis and IPTH may all be part of an overlapping spectrum of immune-mediated injury occurring in the late post-transplant liver allograft. Careful clinico-pathological correlation is very important and the wording of the biopsy report should take into account therapeutic implications, particularly whether changes in immunosuppression may be indicated. This article will provide an overview of the main histological changes occurring in long-term survivors post-LT, focusing on areas where the assessment of late post-transplant biopsies is most relevant clinically.

Recurrent hepatitis C and acute allograft rejection: clinicopathologic features with emphasis on the differential diagnosis between these entities

Chronic hepatitis C virus infection is the leading etiology for liver transplantation in the United States. Recurrent hepatitis C occurs nearly universally in these patients and represents a serious posttransplantation complication. Despite the detailed characterization of the histologic features of both recurrent hepatitis C and acute cellular rejection (ACR) over the last decades, the pathologic distinction between these 2 conditions remains one of the greatest diagnostic challenges in liver pathology. An accurate diagnosis, nevertheless, plays an essential role in patient management, as different therapeutic strategies are used for these conditions. In this review, the clinicopathologic features of posttransplantation recurrent hepatitis C and ACR are discussed, with emphasis on distinguishing histopathologic features, morphologic variants, ancillary techniques, and diagnostic pitfalls.

Potent antifibrotic activity of mTOR inhibitors sirolimus and everolimus but not of cyclosporine A and tacrolimus in experimental liver fibrosis

BACKGROUND & AIMS

Recurrence of chronic hepatitis C and progressive fibrosis in liver transplants is frequent and impairs both graft and patient survival. Whether or not the choice of immunosuppression affects progression of fibrosis remains unclear. The aim of the present study was to compare the potential of the commonly used immunosuppressants to halt experimental liver fibrosis progression.

METHODS

To induce liver fibrosis, rats underwent bile duct ligation and treatment with sirolimus (2mg/kg), everolimus (3mg/kg), tacrolimus (1mg/kg), and cyclosporin A (10mg/kg) daily for 5 weeks. Fibrosis, inflammation, and portal pressure were evaluated by histology, hydroxyproline levels, morphometry, hemodynamics, and hepatic gene expression.

RESULTS

Sirolimus and everolimus decreased fibrosis up to 70%, improved portal pressure, reduced ascites, and showed potent down-regulation of pro-fibrogenic genes, paralleled by a strong increase in matrix degradation (collagenase) activity; in contrast, tacrolimus and cyclosporine A had no or even aggravating effects on liver fibrosis in rats.

CONCLUSIONS

mTOR inhibition by sirolimus and everolimus in experimental liver fibrosis associates with significantly less fibrosis progression and portal hypertension than treatment with calcineurin inhibitors tacrolimus and cyclosporine A. These data suggest that the selection of the immunosuppressant could impact the recurrence of fibrosis in liver allografts.

Transcriptome at the time of hepatitis C virus recurrence may predict the severity of fibrosis progression after liver transplantation

Allograft gene expression analysis may provide insights into the mechanisms involved in liver damage during hepatitis C virus recurrence (HCVrec) after orthotopic liver transplantation (OLT) and allow the identification of patients who have a higher risk of developing severe disease. Forty-three OLT recipients with hepatitis C virus (HCV) were evaluated. Genomewide gene expression analysis was performed with formalin-fixed, paraffin-embedded (FFPE) liver biopsy samples obtained from 21 OLT recipients with HCV at the time of clinical HCVrec, which was defined as increased alanine aminotransferase levels and detectable HCV RNA levels in serum. Patients were classified into 3 groups according to the severity of the fibrosis in the liver biopsies at 36 months post-OLT : group 1 (G1) for mild fibrosis (F0-F1), group 2 for moderate fibrosis (F2), and group 3 (G3) for severe fibrosis (F3-F4). No significant differences were observed between the groups with respect to donor age, histology during HCVrec, treated episodes of acute cellular rejection, or immunosuppression therapy. The results were validated in the remaining 22 OLT recipients with HCV using quantitative real-time polymerase chain reaction. Fifty-seven beadtypes showed significantly different expression (P < 0.001) between the groups during HCVrec. In G3, the gene expression of interleukin-28RA (IL-28RA), IL-28, and angiotensin-converting enzyme was up-regulated. Samples from G1 and G3 were used to determine whether a multigenetic classifier could be derived to predict the group class. The final model included the intercept and 9 bead types. Pairwise scatter plots of these 9 bead types revealed that G1 and G3 were well separated with respect to each gene. Our analysis has demonstrated the utility of a set of molecular markers indicating HCVrec severity early after OLT.

Immune response to extracellular matrix collagen in chronic hepatitis C-induced liver fibrosis

Hepatitis C virus (HCV) infection and its recurrence after orthotopic liver transplantation (OLT) are associated with the remodeling of extracellular matrix (ECM) components [particularly collagen (Col)], which leads to fibrosis. Our aim was to determine whether the development of antibodies (Abs) to self-antigen Col in HCV-infected patients correlates with the fibrosis stage and the peripheral cytokine response. Patients with chronic HCV infection, patients with HCV recurrence after OLT who had undergone a biopsy procedure, and healthy control subjects were enrolled. The HCV subjects (n = 70) were stratified as follows: (1) a non-OLT group without fibrosis (Scheuer stages 0-2), (2) a non-OLT group with fibrosis (Scheuer stages 3-4), (3) a post-OLT group without fibrosis (Scheuer stages 0-2), and (4) a post-OLT group with fibrosis (Scheuer stages 3-4). Serum samples were analyzed for Abs against Col1, Col2, Col4, Col5, and vimentin with enzyme-linked immunosorbent assays. Serum levels of cytokines were measured with multiplex bead immunoassays. The levels of Abs to Col1 were higher in the fibrosis groups versus the no-fibrosis groups and the controls for both non-OLT patients (P < 0.001) and post-OLT patients (P = 0.01). There were increased levels of Abs to Col2, Col4, Col5, and vimentin in the non-OLT fibrosis group (Col2, P = 0.0001; Col4, P = 0.122; Col5, P < 0.0001; vimentin, P = 0.36) and in the post-OLT fibrosis group (Col2, P = 0.006; Col4, P = 0.19; Col5, P < 0.0001; vimentin, P = 0.24) in comparison with the no-fibrosis groups. The non-OLT and post-OLT fibrosis groups demonstrated significantly higher T helper 2 (T(h) 2) and T helper 17 (T(h) 17) cytokine levels and lower T helper 1 cytokine levels in comparison with the no-fibrosis groups. Our results demonstrate that in HCV-infected patients, the levels of Abs to ECM Col1, Col2, and Col5 positively correlate with liver fibrosis, which is associated with a predominantly T(h) 2 and T(h) 17 cytokine profile.

Immune-mediated complications of the graft in interferon-treated hepatitis C positive liver transplant recipients

Hepatitis C virus (HCV) re-infection of the graft is universal and interferon based antiviral therapy remains at present the treatment of choice in HCV liver transplant recipients. Apart from the antiviral effects, interferon and ribavirin have both potent immunomodulatory properties resulting in a broad range of immune-related disorders including acute cellular rejection and chronic ductopenic rejection as well as de novo autoimmune hepatitis. Further complicating the picture, HCV infection per se is associated with a variety of autoimmune phenomena. We discuss here the immune-mediated complications and their relationship to chronic HCV and interferon based antiviral therapy.

CD28 and KIR2D receptors as sensors of the immune status in heart and liver transplantation

Viral infections and cellular acute rejection (AR) condition immunosuppressive therapy and compromise the evolution of allografts. Immune monitoring can be useful for ascertaining rejection and for differentiating allo-reaction from activation induced by infections. This work analyzes the usefulness of monitoring the expression of CD28 and KIR2D receptors in peripheral blood T lymphocytes by flow cytometry, to ascertain the immune response in heart and liver transplant recipients. In both types of transplant, the up-regulation of CD28 in CD4(+) lymphocytes in the periods of greatest AR frequency indicates an effective allo-response, whereas the post-transplantation emergence of circulating CD8(+)CD28(-) and CD8(+)CD28(-)KIR2D(+) T cells correlates with better early clinical results. Cytomegalovirus (CMV) infection, but not hepatitis C virus (HCV) or other infections, abrogated both CD28 up-regulation and CD8(+)CD28(-)KIR2D(+) T-cell expansion. Our results show that monitoring the expression of CD28 and KIR2D receptors on T lymphocytes might be considered as sensors of the immune status of heart and liver recipients.

Explanted liver inflammatory grade predicts fibrosis progression in hepatitis C recurrence

Factors present prior to liver transplantation (LT) that predict fibrosis progression in recurrent hepatitis C infection (HCV) after LT would be important to identify. This study sought to determine if histologic grade of HCV in the explant predicts fibrosis progression in recurrent HCV. The clinical and histologic data of all 159 patients undergoing their first LT for HCV at our center from 1998 to 2001 were retrospectively reviewed with follow-up through June 2008. Twenty-five cases were excluded for: non-HCV-related graft loss <90 days (19), recidivism (4), or unavailable explant or follow-up biopsies (2). A single pathologist scored (Ishak) explants in a blinded fashion. Patients were grouped by explant inflammatory grade ≤ 4 (group1) and >4 (group 2). Prospectively scored liver biopsies (protocol months 1 and 4, annually, and as indicated clinically) were reviewed for development of advanced fibrosis (bridging or cirrhosis). Cox proportional hazard regression was used to analyze the association of explant grade, donor, viral and LT factors with progression to advanced fibrosis. The groups were well-matched for patient, viral, donor, and transplant factors. Five-year advanced fibrosis-free survival in group 1 versus group 2 was 63% versus 28%, P < 0.001. Explant grade >4 was associated with increased HCV-related graft loss at 1 (6% versus 3%) and 5 (36% versus 14%) years post-LT (P = 0.003). On univariate and multivariate Cox regression analysis, predictors of advanced fibrosis were explant grade >4 (hazard ratio [HR] = 3.3, 95% confidence interval [CI] = 1.9-5.6, P < 0.001) donor age >50 (HR = 3.3, 95% CI = 1.9-5.7, P < 0.001) and viral load at LT of >158,730 IU/mL (HR = 1.8, 95% CI = 1.05-3.1, P = 0.03).

CONCLUSION

Explant histologic grade can identify patients requiring more aggressive monitoring and intervention for HCV recurrence post-LT.

Long-term, maintenance MMF monotherapy improves the fibrosis progression in liver transplant recipients with recurrent hepatitis C

Hepatitis C virus (HCV) recurrence after orthotopic liver transplantation (LT) is universal. We designed a retrospective case-control study to evaluate the effect of mycophenolate mofetil (MMF) monotherapy in patients with recurrent hepatitis C. Fifteen patients with histologically proven hepatitis C recurrence after LT were switched from calcineurin inhibitors (CNIs) to MMF monotherapy because of impairment of kidney function and/or metabolic side effects, and treated for 48 months (MMF group). Fifteen well-matched LT recipients who continued to receive CNIs therapy over the same period served as control group. Demographics, clinical data, time after LT, and baseline liver biopsies were similar in the two groups. There was no worsening of hepatic fibrosis during the study in the MMF group [2.6 ± 1.5 (baseline) Ishak Units vs. 2.7 ± 1.8 (after 48 months of MMF treatment), P = 0.6]. In contrast, a significant increase in the fibrosis score [2 ± 1.1 (baseline) vs. 3.2 ± 1.7 (after 48 months of CNI treatment), P = 0.0002] was observed in the control group. The yearly fibrosis progression rate was of 0.05 ± 0.44 in the MMF group and 0.33 ± 0.24 in the CNI group (P = 0.04). MMF monotherapy is associated with a favourable effect on hepatic fibrosis progression in HCV liver transplant recipients.

Transforming growth factor β1 polymorphisms and progression of graft fibrosis after liver transplantation for hepatitis C virus--induced liver disease

Re-infection with the hepatitis C virus (HCV) is an important development after liver transplantation (LT); it can lead to graft fibrosis. The aim of this study was to assess the role of transforming growth factor β1 (TGF-β1) polymorphisms in the development of HCV-related graft disease by evaluating protocol liver biopsies. A total of 192 patients with a recurrence of HCV infection after LT were genotyped for TGF-β1 codon 10 (C→T) and codon 25 (G→C) using the polymerase chain reaction. Histological evaluation of 614 protocol liver biopsies obtained from these patients was undertaken using the classification of Desmet and Scheuer to stage the degree of fibrosis. Mild stages of fibrosis (0-2) were compared to advanced stages of fibrosis (3-4) that developed during the period of infection with the virus. Correlations between the prevalence of TGF-β1 genotypes and the different degrees of fibrosis that developed were determined. No statistically significant differences were found for genotype distributions (codons 10 and 25) with respect to recipient age, donor sex, occurrence of acute cellular rejection, and response to antiviral therapy. However, the C allele at codon 25 was significantly less frequent in the group with advanced fibrosis (P = 0.001). Furthermore, a positive association was found between progression of fibrosis and male recipient sex (P = 0.024), donor age (P = 0.041), and viral genotype 1b (P = 0.002). In conclusion, this study, in which the evolution of hepatic fibrosis was assessed histologically in a large cohort of patients with HCV re-infection after LT, has demonstrated that the C allele at codon 25 of the TGF-β1 gene is a marker for the development of graft fibrosis.

Liver transplant pathology - messages for the non-specialist

This review, based on a presentation at the BDIAP meeting in London 2008, aims to guide histopathologists working outside transplant centres in the differential diagnosis of late post transplant liver biopsies. It focuses on the histological patterns of the late post transplant complications - autoimmune hepatitis, acute and chronic rejection, recurrent viral hepatitis, and biliary disease. Analysis of the character and distribution of inflammatory infiltrate, bile duct changes, and fibrosis by the histopathologist must then be set within the clinical context to arrive at the most appropriate diagnosis. For this reason, review of the biopsy at the transplant centre is recommended. In a broader context, the tabulation of diagnostic features in chronic inflammatory liver diseases produced by the Banff Working Group can, with the exception of rejection, usefully be applied outside the transplant setting.

Retransplantation in patients with hepatitis C recurrence after liver transplantation

Hepatitis C virus (HCV) infection recurs universally after liver transplantation (LT) and fibrosis progression is accelerated in the graft. Retransplantation (RT) is the only therapeutic option to achieve long-term survival in patients with decompensated cirrhosis after LT. Patient and graft survival rates after RT are inferior to those after primary LT. It is generally accepted that severe hepatitis C recurrence (cholestatic hepatitis) and forms with rapid fibrosis progression have a poor survival after RT. However, it is not clear whether rapid fibrosis progression in the first graft will be followed by the same rate of fibrosis progression in the second graft. The use of prognostic scores as screening tools has shown an improvement in survival in HCV-infected patients after RT, reaching similar survival rates as those obtained in non HCV-infected patients. Moreover, these scores can identify candidates with a high risk of mortality in whom the use of a new organ would be unreasonable. Prevention of severe hepatitis C recurrence could be the first step to avoid RT. Thus, antiviral treatment on the waiting list (if possible) and early identification and treatment of patients with severe hepatitis C recurrence may be a good strategy to avoid RT. In addition, active management of factors which can accelerate fibrosis progression (donor age, post-transplant diabetes, high dose of corticosteroids) might reduce the incidence of severe forms of hepatitis C recurrence.

Serological profile of pretransplantation liver patients

INTRODUCTION

A liver transplantation is the first choice of treatment for patients with hepatic insufficiency due to chronic diseases. Infections in the postoperative period represent one of the main causes of mortality in these cases. However, few articles have evaluated the predominance of certain infectious diseases and their influence on postoperative mortality.

METHODS

We retrospectively evaluated the medical records of 236 patients who underwent liver transplantation from January 1997 to January 2007. In these records we checked the serological profiles for these diseases: toxoplasmosis, syphilis, human T lymphotropic virus (HTLV) I and II infection, Chagas disease, hepatitis A, hepatitis B, hepatitis C, paracoccidioidomycosis, tuberculosis, acquired immunodeficiency syndrome, cytomegalovirus (CMV), and mononucleosis (Epstein-Barr virus [EBV]). The statistical analysis was performed by table frequencies.

RESULTS

CMV showed positivity (CMV-IgG) in 94.7% of patients, 95.8% for EBV, 33.3% for toxoplasmosis, 47.9% for hepatitis C, and 5% for hepatitis B.

CONCLUSION

Our analysis showed the importance of serological investigations and diagnostic examinations before the transplantation procedure, seeking to minimize possible reactivation of the disease after the use of immunosuppression drugs, particularly in the first 6 months after transplantation, or even to avoid a primary infection.

Hepatic lipid peroxidation and antioxidant micronutrients in hepatitis virus C liver recipients with and without disease recurrence

BACKGROUND

Hepatitis C virus (HCV) reinfection after liver transplantation is universal and progresses to cirrhosis in 10% to 30% of patients. Several risk factors are associated with progression. Oxidative stress may be involved because it has a role in the pathogenesis of HCV.

OBJECTIVE

To determine whether HCV liver recipients with disease recurrence are more oxidatively stressed than those with no recurrence.

METHODS

Measurements were performed at 12 months posttransplantation, and in a subgroup of patients at 6 months. Liver lipid peroxidation (LPO), antioxidant potential, plasma vitamin E, retinol, and vitamin C were measured. Demographic data, pretransplantation viral load, anthropometry, and 3-day food records were also obtained. Data were log-transformed; analysis was performed using the independent t test, Pearson correlation, and multivariate regression analysis.

RESULTS

Recipients of HCV livers with recurrence (n = 21) had higher liver LPO (mean [SEM] micromoles of malondialdehyde per gram of liver tissue, 1.66 [0.28]) vs those with no recurrence (n = 16; 0.88 [0.13]) (P = .02). A significant relationship was found between liver LPO and HCV recurrence, and this significance continued when accounting for pretransplantation viral load and donor age. Six patients with recurrence and 11 with no recurrence also had measurements obtained at 6 months posttransplantation. Those with recurrence at 12 months had significantly higher hepatic LPO at 6 months (1.86 [0.62]) compared with those with no recurrence (0.75 [0.14]) (P = .04).

CONCLUSIONS

Recipients of HCV livers with recurrence are more oxidatively stressed at 6 and 12 months compared with those with no recurrence. Accounting for viral load and donor age, oxidative stress was independently associated with recurrence. More research is needed to confirm this association.

Monitoring peripheral blood CD4+ adenosine triphosphate activity in recurrent hepatitis C and its correlation to fibrosis progression

The recurrence of hepatitis C virus (HCV) after orthotopic liver transplantation (OLT) is often associated with rapid fibrosis progression attributed to the state of impaired cellular immunity. At present, there are no means to predict those at risk for progression. Peripheral blood CD4+ adenosine triphosphate (ATP) release (the ImmuKnow assay) correlates with immunoreactivity and has been used to monitor global cellular immune function in transplant recipients. The aim of this study was to assess the relationship between cellular immune function measured by the ImmuKnow assay and fibrosis progression in patients with HCV recurrence after OLT. The ImmuKnow assay was prospectively performed in adult HCV patients at 4 and 12 months post-OLT. Protocol liver biopsies were performed (on day 7, in month 4, and yearly) after OLT. The first biopsy that showed fibrosis post-OLT was used to determine the time interval for developing fibrosis. Sixty-two patients met the inclusion criteria. The median follow-up time was 12 (6.5-12.1) months. Fibrosis progression was observed in 61.3% of the patients. ATP levels were lower in patients with fibrosis progression in comparison with patients without progression at 4 months (145 versus 259 ng/mL, P < 0.001) and at 12 months (152 versus 264 ng/mL, P = 0.008). ATP levels at 4 and 12 months post-OLT were found to be significantly associated with a higher hazard of progression. For each 25-unit increase in ATP levels at 4 and 12 months after transplantation, the hazard of fibrosis progression decreased by 22% (P = 0.001) and 12% (P = 0.015), respectively. In conclusion, greater suppression of cellular immunity, as measured by the ImmuKnow assay, is associated with more rapid progression of fibrosis in patients with recurrent HCV post-OLT. Post-OLT monitoring of CD4+ ATP activity may identify a subset of patients at greatest risk for early fibrosis progression.

Liver stiffness identifies two different patterns of fibrosis progression in patients with hepatitis C virus recurrence after liver transplantation

Significant liver fibrosis (F >or= 2) and portal hypertension (hepatic venous pressure gradient [HVPG] >or= 6 mmHg) at 1 year after liver transplantation (LT) identify patients with severe hepatitis C recurrence. We evaluated whether repeated liver stiffness measurements (LSM) following LT can discriminate between slow and rapid "fibrosers" (fibrosis stage F2-F4 at 1 year after LT). Eighty-four patients who had undergone LT and who were infected with hepatitis C virus (HCV) and 19 LT controls who were not infected with HCV underwent LSM at 3, 6, 9, and 12 months after LT. All HCV-infected patients underwent liver biopsy 12 months after LT (paired HVPG measurements in 74); 31 (37%) were rapid fibrosers. Median LSM (in kilopascal) at months 6, 9, and 12 were significantly higher in rapid fibrosers (9.9, 9.5, 12.1) than in slow fibrosers (6.9, 7.5, 6.6) (P < 0.01 all time points). The slope of liver stiffness progression (kPa x month) in rapid fibrosers (0.42) was significantly greater than in slow fibrosers (0.05) (P < 0.001), suggesting two different speeds of liver fibrosis progression. Figures were almost identical for patients with HVPG >or= 6 mmHg or HVPG < 6 mmHg at 1 year after LT. Multivariate analysis identified donor age, bilirubin level, and LSM as independent predictors of fibrosis progression and portal hypertension in the estimation group (n = 50) and were validated in a second group of 34 patients. The areas under the receiver operating characteristic curve that could identify rapid fibrosers and patients with portal hypertension as early as 6 months after LT were 0.83 and 0.87, respectively, in the estimation group and 0.75 and 0.80, respectively, in the validation group.

CONCLUSION

Early and repeated LSM following hepatitis C recurrence in combination with clinical variables discriminates between rapid and slow fibrosers after LT.

Evolution of hepatitis C virus in liver allografts

1. Hepatitis C virus (HCV) RNA+ liver allograft recipients invariably reinfect the liver allograft within hours after transplantation, and the majority (>70%) develop chronic hepatitis. The rate at which these patients experience progression to cirrhosis and the overall percentage are significantly increased in comparison with HCV infection in the nontransplant setting. 2. Core needle biopsy evaluation is used to establish the diagnosis of recurrent HCV, which can be difficult to distinguish from acute cellular rejection and other causes of allograft dysfunction. In the vast majority of cases, however, distinguishing recurrent HCV from other posttransplant syndromes is reliably achieved by a careful examination of hematoxylin and eosin-stained sections and correlation with clinical and serological data. 3. Recurrent HCV often coexists with other causes of liver allograft dysfunction, and the determination of the most important cause of injury and whether other causes of injury are present is important. Included are residual changes of preservation/reperfusion injury, biliary sludging/structuring, acute cellular and chronic rejection, and autoimmune hepatitis. 4. The complex interplay between immunosuppression management, viral replication, and the recipient immune system results in distinct patterns of recurrent chronic HCV in the liver allograft: (1) conventional or usual acute and chronic HCV, which resembles that seen in the general population with HCV; (2) fibrosing cholestatic hepatitis; and (3) plasma cell-rich HCV, which might represent a variant of, or overlap with, autoimmune hepatitis and rejection. 5. The variable but usually hastened histopathological progression toward cirrhosis in HCV+ allografts is similar to that seen in the nontransplant setting, but in allografts, the overall severity of lymphocytic inflammation is less, and ductular reactions, stellate cell activation, and subsinusoidal fibrosis are accentuated. Hepatic stressors and causes of an impaired ability of hepatocytes to replicate include persistently high levels of viral replication, HCV-specific CD4+ T responses, advanced donor age, high levels or rapid withdrawal of immunosuppression, and coexistent liver damage from preservation/reperfusion injury, biliary structuring, or coexistent cytomegalovirus or herpes 6 viral infection. 6. Immunological effector mechanisms involved in the rejection and control of HCV replication/HCV elimination show significant overlap. Patients with very high levels of HCV RNA rarely show significant clinically significant acute or chronic rejection, whereas their occurrence is frequently associated with very low levels or clearance of HCV RNA. Studying the evolution from recurrent HCV to acute rejection in patients treated with interferon and/or weaned from immunosuppression might provide valuable insights into the relationship between these 2 processes as well as liver allograft acceptance.

Lack of killer immunoglobulin-like receptor 2DS2 (KIR2DS2) and KIR2DL2 is associated with poor responses to therapy of recurrent hepatitis C virus in liver transplant recipients

Killer immunoglobulin-like receptors (KIRs) expressed on natural killer and natural killer T cells are involved in activation of these cells and can influence antiviral immunity in the liver. This study investigated the association between KIR genetic diversity and sustained virologic response (SVR) to Peginterferon and Ribavirin (Peg/RBV) therapy in liver transplant (LT) recipients with hepatitis C virus (HCV) recurrence. We tested KIR genotypes in 44 HCV-infected LT recipients treated with Peg/RBV for 48 weeks. Patients were categorized as having KIR genotypes A/A or B/x and analyzed for association with SVR. Fifteen of 44 (34%) patients had SVR. Only 2 of 18 (11%) who lacked KIR2DS2/KIR2DL2 achieved SVR compared to 13 of 26 (50%) who carried these two genes (odds ratio: 8.0, 95% confidence interval: 1.5-42.0, P = 0.008). The association between lack of KIR2DS2/KIR2DL2 and SVR remained significant after exclusion of 10 patients with non-genotype 1 HCV. No correlation was found with other activating or inhibitory KIR genes. Absence of KIR2DS2 and/or KIR2DL2 is associated with failure of Peg/RBV therapy in patients with recurrent HCV after LT. These findings support the role of natural killer and natural killer T cells in HCV clearance after LT and might be generalizable to treatment of HCV infection outside the setting of LT.

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.

The effect of donor race on the survival of Black Americans undergoing liver transplantation for chronic hepatitis C

The purpose of this study was to determine the effect of donor race on the outcome of black patients with chronic hepatitis C infection who undergo liver transplantation. The records for deceased donor liver transplants that occurred in the United States between January 1998 and December 2007 were obtained from the United Network for Organ Sharing. 26,212 records contained sufficient data to be included in the analysis. Of these, 11,989 (45.7%) records were for patients positive for hepatitis C virus (HCV) and 1292 (4.9%) were for patients both HCV-positive and black. Black recipients with white donors were found to have significantly worse outcomes than all other recipient-donor race combinations (P < 0.001). The crude 5-year survival rate for black recipients who had a black donor was 14% higher than the 5-year survival rate for black recipients who had a white donor. Multivariate regression analysis determined that a graft from a race-unmatched donor was an independent risk factor for graft failure (hazard ratio = 1.41, 95% confidence interval = 1.11-1.79) among HCV-positive black recipients but not among HCV-negative black recipients after adjustments for donor age, recipient age, cold ischemia time, serum creatinine, serum bilirubin, diabetes mellitus, body mass index, and donor cytomegalovirus status. The observation that race-unmatched grafts are a risk factor in HCV-positive black recipients, but not in HCV-negative black recipients, suggests an alteration of the graft-host relationship by HCV. In conclusion, our results suggest that HCV-positive black recipients who undergo liver transplantation can have increased graft survival if their donors are black, with survival rates approaching those of white liver transplant recipients.

New insights into the immunopathogenesis of chronic hepatitis C

Despite the high propensity of hepatitis C virus to establish chronic viral persistence, immune-mediated viral clearance occurs in some patients, fostering hopes that therapeutic induction of specific antiviral immune responses might be able to contribute to viral clearance in chronically infected patients. Indeed, recent clinical trials of therapeutic vaccination have provided clear proof of concept that specific immunotherapy can reduce the viral load in some patients. Further improvement of these strategies will depend on a detailed analysis of the immunopathogenesis of chronic hepatitis C. Recent advances in our understanding of the mechanisms of down-regulation of virus-specific immune responses during chronic infection, including the role of regulatory T cells and inhibitory molecules such as programmed death receptor 1, may open up new avenues for second-generation immunotherapeutic interventions.