The impact of sirolimus on hepatitis C recurrence after liver transplantation

mTOR Inhibition and Clinical Transplantation: Liver

The evidence base concerning use of mammalian target of rapamycin (mTOR) inhibitor therapy after liver transplantation is evolving rapidly, clarifying their benefits and disadvantages in different clinical scenarios. The H2304 trial showed that starting everolimus at 1 month posttransplant, with reduced tacrolimus, achieves a sustained improvement in renal function versus standard tacrolimus-based therapy, with at least equivalent immunosuppressive efficacy. Randomized studies evaluating early discontinuation of calcineurin inhibitor (CNI) therapy after introduction of an mTOR inhibitor consistently demonstrated a substantial improvement in renal function versus standard CNI therapy. However, concomitant mycophenolic acid is advisable to avoid an increase in mild biopsy-proven acute rejection, and induction with an interleukin-2 receptor antagonist may also be helpful. High-quality robust data regarding prevention of posttransplant malignancies under mTOR inhibitors is lacking in liver transplantation, although there are some indications of benefit. In maintenance patients, robust data are limited regarding mTOR inhibitor initiation in response to deteriorating renal function or other indications but late conversion (>1 year) appears ineffective. Rates of mTOR inhibitor discontinuation due to adverse events are high, affecting at least a quarter of patients. In conclusion, the evidence base for use of mTOR inhibitors early posttransplant to support CNI reduction now convincingly demonstrates a renal advantage, but adequate adjunctive immunosuppression is essential to preserve efficacy.

The impact of immunosuppressant therapy on the recurrence of hepatitis C post-liver transplantation

The use of immunosuppressants to reduce the likelihood of acute graft rejections is a cornerstone in the post-transplantation management of recipients. However, these agents were always associated with increased risk of deleterious effects such as infections vulnerability and comorbidities. The objective of this review is to discuss the impact of different immunosuppression strategies used in liver transplant recipients (LTRs) on the recurrence of hepatitis C virus (HCV) infections after transplantation. Traditionally, corticosteroids were a mainstay in immunosuppressive regimens in LTRs. Several trials have suggested early tapering of corticosteroids or steroid-free immunosuppression protocols to minimize metabolic complications and other accompanied adverse events. However, there is no consistent agreement on the apparent benefit of steroid-avoidance regimens on HCV recurrence. At present, calcineurin inhibitors alone or in combination with other immunosuppressants are the standard regimen for immunosuppression in LTRs. Although the use of mycophenolate mofetil and sirolimus were sometimes associated with a significantly lower risk of liver injury as a result of HCV recurrence, they were associated with an increased risk of acute graft rejection compared to calcineurin inhibitors. Consequently, reducing the incidence of HCV recurrence in LTRs could be at the expense of other potential complications. The appropriate selection of adequate immunosuppression could diminish the associated increased risk of HCV recurrence after liver transplantation. However, further clinical studies are still pivotal to establish the appropriate/optimal immunosuppressive therapies for HCV-positive LTRs.

Is PBC a viral infectious disease?

The human betaretrovirus and the closely related mouse mammary tumor virus have been linked with the development of cholangitis and mitochondrial antibody production in patients with primary biliary cholangitis (PBC) and mouse models of autoimmune biliary disease, respectively. In vitro, betaretroviruses have been found to stimulate the expression of mitochondrial autoantigens on the cell surface of biliary epithelial cells. In vivo, both mitochondrial autoantigens and viral proteins have been shown to be co-expressed in biliary epithelium and lymphoid tissue. Notably, both mice and humans make poor antibody responses to betaretrovirus infection, whereas proinflammatory responses to viral proteins have been observed in T lymphocyte studies. Furthermore, proviral integration studies have confirmed the presence of human betaretrovirus in biliary epithelium of patients with PBC. Preliminary proof of principal studies using combination antiretroviral therapy have shown that suppression of viral expression is associated with sustained biochemical response. As the previous regimen used was poorly tolerated, further randomized controlled trials are planned to determine whether betaretrovirus infection plays an important role in the development of PBC.

Effects of the Mammalian Target of Rapamycin Inhibitor Everolimus on Hepatitis C Virus Replication In Vitro and In Vivo

BACKGROUND

The influence of immunosuppressants on hepatitis C virus (HCV) re-infection after liver transplantation, particularly mammalian target of rapamycin inhibitors, remains unclear. The aim of our study was to analyze the influence of everolimus (EVR) on HCV replication activity in the context of underlying molecular mechanisms, with focus on the pro-myelocytic leukemia protein (PML).

METHODS

HCV viral load was recorded in 40 patients with post-transplant HCV re-infection before and 8 weeks after introduction of EVR. An HCV cell culture replicon system for genotype (GT) 1b, GT2b, and GT3a was used to compare the influence of EVR on HCV replication for the respective genotypes in vitro. Fluorescence-activated cell-sorting analysis was used to test for effects on cell proliferation. PML expression was silenced with the use of small hairpin RNA constructs, and PML expression was quantified by means of quantitative real-time polymerase chain reaction.

RESULTS

In patients with HCV, the viral load of GT1a and GT1b was hardly affected by EVR, whereas the viral load was reduced in patients with GT2a (P ≤ .0001) or GT3 infection (P ≤ .05). In vitro EVR impairs HCV replication activity of GT2a and GT3a up to 60% (P ≤ .0005), whereas in GT1b cells, HCV replication activity is increased by 50% (P ≤ .005). Replicon cell viability was not impaired. HCV replication activity is impaired in the absence of PML, which can be reversed by overexpression of PML isoforms. Furthermore, in the absence of PML, the effect of EVR on HCV replication activity is nearly abrogated.

CONCLUSIONS

The mammalian target of rapamycin inhibitor EVR influences HCV replication via PML. The herein presented results suggest a genotype-dependent benefit for an EVR-based immunosuppressive regimen in patients with GT2a or GT3 re-infection after liver transplantation.

Host cell mTORC1 is required for HCV RNA replication

OBJECTIVE

Chronically HCV-infected orthotopic liver transplantation (OLT) recipients appear to have improved outcomes when their immunosuppressive regimen includes a mammalian target of rapamycin (mTOR) inhibitor. The mechanism underlying this observation is unknown.

DESIGN

We used virological assays to investigate mTOR signalling on the HCV replication cycle. Furthermore, we analysed HCV RNA levels of 42 HCV-positive transplanted patients treated with an mTOR inhibitor as part of their immunosuppressive regimen.

RESULTS

The mTOR inhibitor rapamycin was found to be a potent inhibitor for HCV RNA replication in Huh-7.5 cells as well as primary human hepatocytes. Half-maximal inhibition was observed at 0.01 µg/mL, a concentration that is in the range of serum levels seen in transplant recipients and does not affect cell proliferation. Early replication cycle steps such as cell entry and RNA translation were not affected. Knockdown of raptor, an essential component of mTORC1, but not rictor, an essential component of mTORC2, inhibited viral RNA replication. In addition, overexpression of raptor led to higher viral RNA replication, demonstrating that mTORC1, but not mTORC2, is required for HCV RNA replication. In 42 HCV-infected liver-transplanted or kidney-transplanted patients who were switched to an mTOR inhibitor, we could verify that mTOR inhibition decreased HCV RNA levels in vivo.

CONCLUSIONS

Our data identify mTORC1 as a novel HCV replication factor. These findings suggest an underlying mechanism for the observed benefits of mTOR inhibition in HCV-positive OLT recipients and potentiate further investigation of mTOR-containing regimens in HCV-positive recipients of solid organ transplants.

Role of mTOR inhibitors for the control of viral infection in solid organ transplant recipients

Appropriate post-transplant immunosuppressive regimens that avoid acute rejection, while reducing risk of viral reactivation, have been sought, but remain a chimera. Recent evidence suggesting potential regulatory and antiviral effects of mammalian target of rapamycin inhibitors (mTORi) is of great interest. Although the concept of an immunosuppressive drug with antiviral properties is not new, little effort has been made to put the evidence together to assess the management of immunosuppressive therapy in the presence of a viral infection. This review was developed to gather the evidence on antiviral activity of the mTORi against the viruses that most commonly reactivate in adult solid organ recipients: cytomegalovirus (CMV), polyomavirus, Epstein-Barr virus (EBV), human herpesvirus 8 (HHV8), and hepatitis C virus (HCV). A rapid review methodology and evaluation of quality and consistency of evidence based on the GRADE system was used. The existing literature was variable in nature, although indicating a potential advantage of mTORi in CMV, polyomavirus, and HHV8 infection, and a most doubtful relation with EBV and HCV infection. Several recommendations about the management of these infections are presented that can change certain current patterns of immunosuppression and help to improve the prognosis of the direct and indirect effects of viral infection in solid organ recipients.

A retrospective 15-year review: survival advantage after switching to sirolimus in hepatitis C virus infected liver graft recipients

BACKGROUND

The use of sirolimus-based immune suppression in liver transplantation, particularly in hepatitis C virus (HCV)-infected recipients, remains contentious. There is some evidence that sirolimus retards hepatic fibrosis, is renal sparing and may be of benefit in preventing hepatocellular carcinoma (HCC) recurrence. Sirolimus has not been adopted by many transplant centres because of persistent concerns regarding an increased risk of hepatic artery thrombosis, graft loss and death with de novo sirolimus.

AIM

To review the impact of switching to sirolimus monotherapy in HCV-infected liver recipients with respect to survival, graft loss and hepatic fibrosis.

METHODS

A retrospective review of 190 patients from a single centre undergoing first liver transplantation for HCV over 15 years. 113 patients were switched from calcineurin inhibitor (CNI)-based therapy to low-dose sirolimus monotherapy at a median of 15 months after transplantation for HCV-related fibrosis (72%), renal impairment (14%) or high-risk HCC (5%).

RESULTS

Patients switched to sirolimus had improved survival (P < 0.001) and slower progression to cirrhosis (P = 0.001). In patients with HCC (n = 91), sirolimus duration rather than strategy was an independent predictor of survival (P = 0.001) and extended time to HCC recurrence (33 vs. 16 months). Patients switched for renal dysfunction showed improvement in serum creatinine (140-108 μmol/L, P = 0.001). Those remaining on CNI-therapy were more likely to develop post-transplant diabetes (P = 0.03).

CONCLUSION

These data suggest selective switching to low-dose sirolimus monotherapy in HCV-positive liver recipients improves clinical outcome.

Fibrosis progression in maintenance liver transplant patients with hepatitis C recurrence: a randomised study of everolimus vs. calcineurin inhibitors

BACKGROUND & AIMS

Robust clinical data evaluating fibrosis progression in hepatitis C virus (HCV) liver transplant patients receiving an mTOR inhibitor vs. calcineurin inhibitor (CNI) are lacking. To evaluate fibrosis progression in maintenance liver transplant patients receiving everolimus- or CNI-based immunosuppression.

METHODS

In a randomised, multicentre, open-label study, 43 maintenance liver transplant patients with recurrent HCV infection were randomised to continue CNI-based immunosuppression or switch to everolimus.

RESULTS

For patients with biopsy data at month 12, mean Ishak-Knodell fibrosis score at baseline was 2.6 ± 0.9 (n = 14) with everolimus vs. 1.9 ± 1.1 (n = 18) with CNI (P = 0.043), and 1.9 ± 1.2 vs. 2.2 ± 1.3 at month 12. Ishak-Knodell fibrosis score decreased from baseline to month 12 by a mean of -0.7 ± 1.1 with everolimus, but increased by 0.2 ± 1.2 with CNI (P = 0.046). No acute rejection or graft losses occurred up to month 12. Estimated GFR at month 12 was 65.6 ml/min/1.73 m² with everolimus and 62.2 ml/min/1.73 m² with CNI [mean difference 3.4 ml/min/1.73 m² compared to CNI control group, 95% CI -4.9, 11.8 ml/min/1.73 m², P = 0.411 (analysis of covariance adjusting for baseline GFR)]. Adverse events occurred in 95.5% of everolimus patients and 71.4% of CNI patients (serious adverse events 31.8% and 0.0%, respectively). Adverse events led to everolimus discontinuation in five patients (22.7%).

CONCLUSIONS

This exploratory study suggests that conversion from CNI to everolimus reduces progression of liver fibrosis, and preserves renal function without jeopardising efficacy in liver transplant recipients with recurrent HCV, but is associated with a higher incidence of adverse events and serious adverse events. These preliminary findings merit examination in a larger trial.

Sirolimus reduces the risk of significant hepatic fibrosis after liver transplantation for hepatitis C virus: a single-center experience

INTRODUCTION

Hepatitis C virus (HCV) recurrence following orthotopic liver transplantation is an expected outcome in all patients transplanted for a primary diagnosis of HCV. HCV recurrence has been shown to be associated with graft fibrosis and graft loss. Recent studies suggest that sirolimus (SRL) therapy may slow or inhibit hepatic fibrosis following liver transplant in patients positive for HCV at the time of transplant.

METHODS

Among 313 patients who underwent orthotopic liver transplantation for HCV between 2000 and 2009, 251 qualified for inclusion in the study. Per protocol liver biopsies were performed on all patients at 1 year following liver transplantation and/or at the time of a clinical diagnosis of HCV recurrence. Biopsies were scored for fibrosis using the Batts-Ludwig staging system (0-4); significant fibrosis was defined as fibrosis ≥ stage 2.

RESULTS

Overall, there was no difference in overall survival or graft loss in the SRL compared with the control group. Multivariate analysis revealed SRL therapy to be associated with decreased odds of significant hepatic fibrosis at year 1 postoperatively and over the study duration.

CONCLUSIONS

This retrospective, single-center study showed sirolimus-based immunosuppression to be associated with a lower risk of significant graft fibrosis, both at year 1 and throughout the study period, following liver transplantation in HCV-infected recipients.

Management of Hepatitis C Before and After Liver Transplantation in the Era of Rapidly Evolving Therapeutic Advances

Management of hepatitis C (HCV) in liver transplantation (LT) population presents unique challenges. Suboptimal graft survival in HCV+ LT recipients is attributable to universal HCV recurrence following LT. Although eradication of HCV prior to LT is ideal for the prevention of HCV recurrence it is often limited by adverse events, particularly in patients with advanced cirrhosis. Antiviral therapy in LT candidates needs careful monitoring, and prophylaxis with HCV antibodies is ineffective. Early antiviral therapy after LT has been investigated, but no clear benefit has been demonstrated. Protocol liver biopsy is generally recommended in HCV+ LT recipients, and antiviral therapy can be considered in those with severe/progressive HCV recurrence. Sustained virological response (SVR) can be achieved in approximately 30% of LT recipients with pegylated interferon/ribavirin (PEG-IFN/RBV) with survival benefit, but adverse effects are common. Favorable patient characteristics for response to therapy include non-1 genotype, previously untreated, low baseline HCV-RNA, and donor IL28B genotype CC. Direct acting antiviral (DAA)-based triple therapy is associated with higher rates of SVR, but with similar or slightly higher rates of side effects, and immunosuppressive regimens need to be closely monitored and adjusted during the treatment period. Notably, the safety and efficacy of HCV treatment are very likely to improve with newer generation DAA. The benefit of immunosuppressive strategy on the natural history HCV recurrence has not been well elucidated. Based upon available evidence, cyclosporine A (CSA), mycophenolate mofetil (MMF), and sirolimus appear to have a neutral or small beneficial impact on HCV recurrence. Donor interleukin 28 B (IL28B) polymorphisms appear to impact the course and treatment outcomes in recurrent HCV. Retransplantation should be considered for patients with reasonable survival probability.

The Role of mTOR Inhibitors in Liver Transplantation: Reviewing the Evidence

Despite the success of liver transplantation, long-term complications remain, including de novo malignancies, metabolic syndrome, and the recurrence of hepatitis C virus (HCV) and hepatocellular carcinoma (HCC). The current mainstay of treatment, calcineurin inhibitors (CNIs), can also worsen posttransplant renal dysfunction, neurotoxicity, and diabetes. Clearly there is a need for better immunosuppressive agents that maintain similar rates of efficacy and renal function whilst minimizing adverse effects. The mammalian target of rapamycin (mTOR) inhibitors with a mechanism of action that is different from other immunosuppressive agents has the potential to address some of these issues. In this review we surveyed the literature for reports of the use of mTOR inhibitors in adult liver transplantation with respect to renal function, efficacy, safety, neurological symptoms, de novo tumors, and the recurrence of HCC and HCV. The results of our review indicate that mTOR inhibitors are associated with efficacy comparable to CNIs while having benefits on renal function in liver transplantation. We also consider newer dosing schedules that may limit side effects. Finally, we discuss evidence that mTOR inhibitors may have benefits in the oncology setting and in relation to HCV-related allograft fibrosis, metabolic syndrome, and neurotoxicity.

Growing experience with mTOR inhibitors in pediatric solid organ transplantation

Controlled trials of mTOR inhibitors in children following solid organ transplantation are scarce, although evidence from prospective single-arm studies is growing. Everolimus with reduced CNI therapy has been shown to be efficacious and safe in de novo pediatric kidney transplant patients in prospective trials. Prospective and retrospective data in children converted from CNI therapy to mTOR inhibition following kidney, liver, or heart transplantation suggest preservation of immunosuppressive efficacy. Good renal function has been maintained when mTOR inhibitors are used de novo in children following kidney transplantation or after conversion to mTOR inhibition with CNI minimization. mTOR inhibition with reduced CNI exposure is associated with a low risk for developing infection in children. Growth and development do not appear to be impaired during low-dose mTOR inhibition, but more studies are required. No firm conclusions can be drawn as to whether mTOR inhibitors should be discontinued in children requiring surgical intervention or whether mTOR inhibition delays progression of hepatic fibrosis after pediatric liver transplantation. In conclusion, current evidence suggests that use of mTOR inhibitors in children undergoing solid organ transplantation is efficacious and safe, but a number of issues remain unresolved and further studies are required.

Immunosuppression in HCV-positive liver-transplant recipients

PURPOSE OF REVIEW

The purpose of this review is to evaluate the historical and recent literature as it pertains to current immunosuppression regimens in hepatitis C virus (HCV)-positive (+) liver-transplant recipients.

RECENT FINDINGS

Recent findings suggest that there are unique differences between HCV transplant recipients and non-HCV transplant recipients, not only in the graft's inflammatory response, but also to the treatments used to prevent and combat rejection.

SUMMARY

HCV (+) transplant recipients present unique challenges. Over the years, there has been progress but there is clearly no consensus regarding the optimal immunosuppressive medications or drug regimens; however, there continues to be advancements in the management of patients with HCV. Though current studies do not provide clear evidence as to optimal immunosuppression, they do identify questions ideally addressed by large, randomized controlled trials.

Genetic variants of STAT-4 affect the development of graft fibrosis after liver transplantation for HCV-induced liver disease

BACKGROUND

Hepatitis C virus (HCV) reinfection after liver transplantation may lead to recirrhosis and seems to be influenced by genetic factors. The aim of our study was to evaluate the role of STAT-4-polymorphisms in the development of HCV-related graft disease based on protocol biopsies.

METHODS

One hundred sixty transplant patients with HCV recurrence were genotyped for STAT-4 (rs7574865) by polymerase chain reaction. Fibrosis stages were determined based on Desmet and Scheuer classification. SPSS was used for the statistical analysis of genotype distribution and of time to the development of advanced fibrosis among the genotypes.

RESULTS

During a comparable observation period of 86.2 months (P=0.654), 65 patients (46.5%) developed advanced fibrosis. Advanced fibrosis was observed significantly more frequent in patients (n=34) with at least one T-allele (53.1 vs. 32.3%; P=0.013) compared with homozygotes for G-allele (n=31). Significant differences in the duration of advanced fibrosis development were detected between patients with at least one T-allele compared with G-allele (34.4 vs. 49.0 months; P=0.022). No impact was observed regarding the outcome of interferon-based antiviral treatment (P=0.297) and the occurrence of acute cellular rejection (P=0.365).

CONCLUSION

Present results indicate a possible impact of genetic confounders in the recipient on graft fibrogenesis, thus explaining significantly different graft behavior observed after transplantation for HCV-associated liver disease. STAT-4-T-allele is identified as fibrogenic factor and seems to have a negative impact on HCV-induced fibrosis development.

Living-donor liver transplantation and hepatitis C

Hepatitis-C-virus- (HCV-) related end-stage cirrhosis is the primary indication for liver transplantation in many countries. Unfortunately, however, HCV is not eliminated by transplantation and graft reinfection is universal, resulting in fibrosis, cirrhosis, and finally graft decompression. In areas with low deceased-donor organ availability like Japan, living-donor liver transplantation (LDLT) is similarly indicated for HCV cirrhosis as deceased-donor liver transplantation (DDLT) in Western countries and accepted as an established treatment for HCV-cirrhosis, and the results are equivalent to those of DDLT. To prevent graft failure due to recurrent hepatitis C, antiviral treatment with pegylated-interferon and ribavirin is currently considered the most promising regimen with a sustained viral response rate of around 30% to 35%, although the survival benefit of this regimen remains to be investigated. In contrast to DDLT, many Japanese LDLT centers have reported modified treatment regimens as best efforts to secure first graft, such as aggressive preemptive antiviral treatment, escalation of dosages, and elongation of treatment duration.

Meeting report of the International Liver Transplantation Society's 18th annual international congress: Hilton San Francisco Hotel, San Francisco, CA, May 16-19, 2012

From May 16-19, 2012, the International Liver Transplantation Society held its annual congress in San Francisco, CA. More than 1300 registrants attended the meeting, which included a premeeting conference entitled Balancing Risk in Liver Transplantation, focused topic sessions, and a variety of oral and poster presentations. This report is not all-inclusive and focuses on specific research abstracts on key topics in liver transplantation. As always, the new data herein are presented in the context of the published literature to further enhance knowledge in the field.

Effect of maintenance immunosuppressive drugs on virus pathobiology: evidence and potential mechanisms

Recent evidence suggesting a potential anti-CMV effect of mTORis is of great interest to the transplant community. However, the concept of an immunosuppressant with antiviral properties is not new, with many accounts of the antiviral properties of several agents over the years. Despite these reports, to date, there has been little effort to collate the evidence into a fuller picture. This manuscript was developed to gather the evidence of antiviral activity of the agents that comprise a typical immunosuppressive regimen against viruses that commonly reactivate following transplant (HHV1 and 2, VZV, EBV, CMV and HHV6, 7, and 8, HCV, HBV, BKV, HIV, HPV, and parvovirus). Appropriate immunosuppressive regimens posttransplant that avoid acute rejection while reducing risk of viral reactivation are also reviewed. The existing literature was disparate in nature, although indicating a possible stimulatory effect of tacrolimus on BKV, potentiation of viral reactivation by steroids, and a potential advantage of mammalian target of rapamycin (mTOR) inhibition in several viral infections, including BKV, HPV, and several herpesviruses.

Impact of sirolimus and tacrolimus on mortality and graft loss in liver transplant recipients with or without hepatitis C virus: an analysis of the Scientific Registry of Transplant Recipients Database

By analyzing 26,414 patients [12,589 with hepatitis C virus (HCV)] in the Scientific Registry of Transplant Recipients Database, we sought to determine comparative risk factors (including primary immunosuppression) predictive of death and graft loss among patients with HCV and patients without HCV. Immunosuppression was examined at the baseline and as a time-dependent variable, and the results were stratified by the transplant center and were adjusted for variables well known to affect patient and graft survival. A multivariate analysis of patient mortality demonstrated that recipient age, donor age, hepatocellular carcinoma, diabetes, and creatinine were significantly associated with increased 3-year mortality for both groups. Tacrolimus-based immunosuppression was associated with superior survival in both groups. In contrast, the use of sirolimus was strongly associated with increased mortality in the HCV group, and cyclosporine was associated with increased mortality in the non-HCV group. Adjusting for known and unknown factors predictive of posttransplant outcomes, a propensity analysis confirmed the association of sirolimus use with an increased risk of death in HCV patients as well as the association of tacrolimus use with a decreased risk of death in all patients. In conclusion, this study suggests a novel association between sirolimus use and an increased risk of death and graft loss after liver transplantation in HCV patients that is not seen in patients without HCV. This study confirms the association of tacrolimus with superior outcomes. Sirolimus should be used sparingly in recipients with HCV infections.

Hepatitis C virus infection in the immunocompromised host: a complex scenario with variable clinical impact

The relationship between Hepatitis C Virus (HCV) infection and immunosuppression is complex and multifaceted. Although HCV-related hepatocytolysis is classically interpreted as secondary to the attack by cytotoxic T lymphocytes against infected cells, the liver disease is usually exacerbated and more rapidly evolutive in immunosuppressed patients. This generally occurs during the immunosuppression state, and not at the reconstitution of the host response after immunosuppressive therapy discontinuation. The field of immunosuppression and HCV infection is complicated both by the different outcome observed in different situations and/or by contrasting data obtained in the same conditions, with several still unanswered questions, such as the opportunity to modify treatment schedules in the setting of post-transplant follow-up. The complexity of this field is further complicated by the intrinsic tendency of HCV infection in itself to lead to disorders of the immune system. This review will briefly outline the current knowledge about the pathogenesis of both hepatic and extrahepatic HCV-related disorders and the principal available data concerning HCV infection in a condition of impairment of the immune system. Attention will be especially focused on some conditions - liver or kidney transplantation, the use of biologic drugs and cancer chemotherapy - for which more abundant and interesting data exist.

[Liver transplantation: personalized immunosuppression in patients with hepatitis C virus infection and hepatocellular carcinoma]

Transplantation has become the treatment of choice in end-stage liver disease, with 5-year survival rates of around 68-74% in European and North-American registries (www.unos.org, www.eltr.org, www.ont.es). These results are largely due to the development of powerful immunosuppressive agents, mainly calcineurin inhibitors. However, these immunosuppressive drugs are not free of adverse effects, especially nephrotoxicity. Moreover, two of the most frequent indications for transplantation, cirrhosis due to hepatitis C virus and hepatocellular carcinoma, can recur in the transplanted graft. Whether specific immunosuppression could be less harmful in these conditions is the subject of debate. With the greater use of suboptimal donors and of expanded criteria for liver transplantation in patients with hepatocellular carcinoma, aggressive recurrences can be expected to increase. The present review attempts to elucidate whether there is an immunosuppression strategy that could minimize the risk of aggressive tumoral recurrence or recurrence of hepatitis C.

Spanish society of liver transplantation (SETH) consensus recommendations on hepatitis C virus and liver transplantation

In November 2010, the Spanish Society of Liver Transplantation (Sociedad Española de Trasplante Hepático, SETH) held a consensus conference. One of the topics of debate was liver transplantation in patients with hepatitis C. This document reviews (i) the natural history of post-transplant hepatitis C, (ii) factors associated with post-transplant prognosis in patients with hepatitis C, (iii) the role of immunosuppression in the evolution of recurrent hepatitis C and response to antiviral therapy, (iv) antiviral therapy, both before and after transplantation, (v) follow-up of patients with recurrent hepatitis C and (vi) the role of retransplantation.

Virus-drug interactions--molecular insight into immunosuppression and HCV

Liver transplantation is an effective treatment for end-stage liver disease that is attributable to chronic HCV infection. However, long-term outcomes are compromised by universal virological recurrence in the graft. Reinfection that occurs after transplantation has increased resistance to current interferon-based antiviral therapy and often leads to accelerated development of cirrhosis. Important risk factors for severe HCV recurrence are linked to immunosuppression. Owing to the lack of good randomized, controlled trials, the optimal choice of immunosuppressants is still debated. By contrast, much progress has been made in the understanding of HCV biology and the antiviral action of interferons. These new insights have greatly expanded our knowledge of the molecular interplay between HCV and immunosuppressive drugs. In this article, we explore the effect of different immunosuppressants on the complex cellular events involved in HCV infection and interferon signalling. Potential implications for clinical practice and future drug development are discussed.

Everolimus in clinical practice in long-term liver transplantation: an observational study

INTRODUCTION

Everolimus, a mammalian target of rapamycin (mTOR) inhibitor, has been used in acute and chronic treatment of kidney and heart transplants. There is scarce information regarding its use in liver transplant recipients, although everolimus may be a useful alternative for selected cases.

OBJECTIVE

The objective of this study was to study the clinical, biochemical, and pathological features of patients to whom everolimus was added based upon defined clinical profiles.

STUDY DESIGN

This study was prospective observational ongoing study to evaluate the effectiveness and safety of everolimus alone or in combination with low doses of a calcineurin inhibitor (CNI). Chronic liver transplant recipients without contraindications to everolimus were defined based upon 7 profiles of complications. The initial everolimus dose (0.25 mg every 12 hours) was overlapped during conversion, measuring blood levels and evaluating clinical tolerance. Routine monitoring was performed to obtain immunosuppressant blood levels near the lower limit of the therapeutic range.

RESULTS

The 35 patients' including 17 men and 18 women, had an overall mean age of 61 ± 10 years with a mean follow-up of 34 months. The everolimus treatment lasted 20 months (range, 6-60). The indication for everolimus conversion were as follows: renal insufficiency (45.7%), no response to hepatitis C virus (HCV) treatment (42.9%), autoimmune hepatitis associated with interferon (8.5%), de novo autoimmune hepatitis (25.5%), de novo tumor (37.1%), neurotoxicity (14.3%), or side effects to rapamycin treatment (5.7%). Patients may have presented more than one indication. Effectiveness was assessed based upon improved liver (48.6%) or renal function (31.25% with renal insufficiency) or withdrawal of prednisone (100% of 10 patients receiving prednisone). CNI was withdrawn from 48.6% of patients due to de novo tumors or neurotoxicity. The side effect were as follows: anemia, leukopenia, or thrombocytopenia (11.4%) or dyslipidemia (27.3%). The survival rate was 94.3%.

CONCLUSIONS

Administration of everolimus to chronic liver transplants enhanced therapeutic options in the long term recipients when applied for predefined clinical indications and administrated with dose adjustments based on serial monitoring of exposure.

Effectiveness and safety of everolimus in the treatment of autoimmune hepatitis related to anti-hepatitis C virus therapy after liver transplant: three case reports

Treatment of recurrent hepatitis C after liver transplantation is indicated in selected cases. During the combined treatment with pegylated interferon and ribavirin, some patients develop immune-mediated liver dysfunction similar to the previously described "de novo" autoimmune hepatitis. Herein we have presented three liver transplant patients who during or after combined antiviral treatment were diagnosed as autoimmune hepatitis related to interferon based on their clinical, biochemical, and liver histology features. There were two women and one man, of ages 49, 52, and 49 years who were transplanted due to cirrhosis related to hepatitis C virus genotype 1. In two patients, elevated liver enzymes occurred during antiviral therapy and in the third, after the therapy. The diagnosis of autoimmune hepatitis was reached after excluding other possible causes. One patient had a sustained viral response; and two cases were nonresponders. Antinuclear antibodies were present in two subjects and antinuclear antibodies and anti-smooth muscle antibodies in the other case. First-line treatment of autoimmune hepatitis with prednisone and azathioprine stabilized clinical and biochemical parameters'. In order to avoid the long-term use of prednisone, everolimus was introduced in the three patients. Interestingly, hepatitis C did not progress and clinical, biochemical, as well as histological parameters stabilized. In one patient, the liver fibrosis stage as assessed by histology showed improvement. However, one subject experienced repeated cerebral hemorrhage and died. Although this is heterogeneous population with partially known characteristics, with a difficult differential diagnosis, the objectives of preserving liver function and avoiding recurrent progressive hepatitis C seemed to be achieved by adding everolimus. In addition, we totally stopped prednisone therapy. In conclusion, treatment with everolimus in combination with cyclosporine achieved a partial remission in two liver transplan cases of autoimmune hepatitis related to interferon therapy.

Liver transplantation and hepatitis C

Hepatitis-C-virus- (HCV-) related end-stage cirrhosis is the primary indication for liver transplantation in many countries. Unfortunately, however, HCV is not eliminated by transplantation and graft reinfection is universal, resulting in fibrosis, cirrhosis, and finally graft decompensation. The use of poor quality organs, particularly from older donors, has a highly negative impact on the severity of recurrence and patient/graft survival. Although immunosuppressive regimens have a considerable impact on the outcome, the optimal regimen after liver transplantation for HCV-infected patients remains unclear. Disease progression monitoring with protocol biopsy and new noninvasive methods is essential for predicting patient/graft outcome and starting antiviral treatment with the appropriate timing. Antiviral treatment with pegylated interferon and ribavirin is currently considered the most promising regimen with a sustained viral response rate of around 30% to 35%, although the survival benefit of this regimen remains to be investigated. Living-donor liver transplantation is now widely accepted as an established treatment for HCV cirrhosis and the results are equivalent to those of deceased donor liver transplantation.

The use of sirolimus should be restricted in liver transplantation

Sirolimus and mTOR inhibitors are important additions to the therapeutic armamentarium to prevent allograft rejection, but their role in liver transplantation is evolving. De novo use of Sirolimus in the early post-transplant period has undoubtedly been influenced by the high incidence of hepatic artery thrombosis and decreased patient and graft survival leading to a black box warning. The jury remains undecided on the role of conversion from CNIs to mTOR inhibitors in those developing renal insufficiency and it must be noted that a second warning was issued by the FDA because of decreased survival in those conversion studies. Finally, the anti-atherogenic, antiviral, and anti-neoplastic effects associated with Sirolimus, which might favor their use in certain liver transplant patients, need further evaluation before firm recommendations can be made.

m-TOR inhibitors: what role in liver transplantation?

The development of calcineurin inhibitors (CNIs) led to marked improvements in patient and graft survival after liver transplantation (LTx). We have been left, however, with a dependence on immunosuppressive agents with nephrotoxicity, neurotoxicity, adverse impacts on cardiac risk profile, and risk for malignancy. These challenges need to be met against a dominance of hepatitis C virus (HCV) and hepatocellular carcinoma (HCC) as indications for liver transplant. Unmet needs for immunosuppression (IS) in LTx include: (1) Effective drugs that avoid CNIs toxicities. (2) Agents without adverse impact on HCV recurrence. (3) Compounds that minimize risk of HCC recurrence. New immunosuppressives will need to address the above needs while supporting patient and graft survival equivalent to those achievable with CNIs, ideally without important new toxicities. Two new classes of agents are currently in advanced clinical development: belatacept, and the mammalian target of rapamycin inhibitors (m-TORi). This manuscript will review evidence for a role for m-TORi in LTx in a range of clinical scenarios including patients with CNI nephrotoxicity or neurotoxicity, patients at risk of (or with) HCV recurrence, and patients at risk of HCC recurrence.

Hot topic in hepatitis C virus research: the type of immunosuppression does not matter

1. The natural history of recurrent hepatitis C virus (HCV) is highly variable. Old donor age is a factor that has consistently been shown to affect disease progression. 2. Overall, immunosuppression determines the progression of HCV-related disease; however, the type of immunosuppressive agent used for induction or maintenance is not a key factor. 3. Steroid boluses should be avoided; they are associated with increased viremia, fibrosis progression, and reduced survival. 4. Antiviral therapy, particularly if it is successful, is associated with improved outcomes for liver transplant recipients with HCV. 5. There are no convincing data for modifying the type of immunosuppression before antiviral therapy is started.

Evolving concepts in the selection of immunosuppression regimen for liver transplant recipients

The introduction of calcineurin inhibitor (CNI) based immunosuppression has revolutionized the field of liver transplantation by dramatically reducing the incidence of acute cellular rejection and prolonging patient and allograft survival. However, the introduction of CNIs has also come at the price of increased patient morbidity, particularly with regard to the well-known nephrotoxic effects of the medications. In an effort to minimize the adverse effects, immunosuppression regimen have evolved to include the use of various induction agents and purine synthesis inhibitors to limit the dose of CNI necessary to achieve low acute cellular rejection rates. Careful assessments of risks and benefits are needed as these newer agents have their own side effect profiles. In addition, the impact of newer immunosuppression regimen on hepatitis C (HCV) recurrence has not been completely elucidated. This review will provide an overview of the most common immunosuppression regimen used in liver transplantation and discuss their impact on acute cellular rejection, patient and allograft survival, and HCV recurrence.