The outcome of hepatitis C virus infection after liver transplantation--is it influenced by the type of immunosuppression?

Role of toll-like receptors in liver transplantation

Toll-like receptors (TLRs) are pathogen recognition receptors that orchestrate the innate immune response and the subsequent adaptive immune response. TLRs can be triggered by exogenous ligands expressed by invading pathogens or by the release of endogenous ligands, such as that occurring through cellular injury during the transplantation process. They are now recognized to play an important role in many facets of transplantation biology, including rejection and tolerance, ischemia/reperfusion injury (IRI), and infections after transplantation. The role of TLRs in liver transplantation is unique with respect to other organ transplants because the portal circulation is a continuous source of TLR2 and TLR4 ligands, and this influences TLR signaling pathways, which have a central role in transplantation immunity. This review provides a critical update on recent data outlining the important role of TLRs in liver transplantation, and there is a particular focus on emerging advances in our understanding of rejection and tolerance, IRI, and infections after transplantation and on the ways in which these events may influence the recurrence of diseases such as hepatitis C infection after liver transplantation.

Hepatitis C recurrence: the Achilles heel of liver transplantation

Hepatitis C virus (HCV) infection is the most common indication for liver transplantation worldwide; however, recurrence post transplant is almost universal and follows an accelerated course. Around 30% of patients develop aggressive HCV recurrence, leading to rapid fibrosis progression (RFP) and culminating in liver failure and either death or retransplantation. Despite many advances in our knowledge of clinical risks for HCV RFP, we are still unable to accurately predict those most at risk of adverse outcomes, and no clear consensus exists on the best approach to management. This review presents a critical overview of clinical factors shown to influence the course of HCV recurrence post transplant, with particular focus on recent data identifying the important role of metabolic factors, such as insulin resistance, in HCV recurrence. Emerging data for genetic markers of HCV recurrence and their usefulness for predicting adverse outcomes will also be explored.

Cyclosporine and tacrolimus have inhibitory effects on toll-like receptor signaling after liver transplantation

Toll-like receptors (TLRs) play a key role in transplantation biology. The effect of immunosuppression on TLR function after liver transplantation is unknown. Peripheral blood mononuclear cells (PBMCs) from 113 post-liver transplant patients and 13 healthy controls were stimulated with TLR-specific ligands [lipopolysaccharide (TLR4), pan-3-cys (P3C) (TLR2), Poly (I:C) (PIC) (TLR3), R848 (TLR7/8), and CpG (TLR9)] for 24 hours. PBMCs from 5 healthy controls were also cultured with therapeutic concentrations of cyclosporine A (CYA) and tacrolimus (TAC). Cytokine production was measured with enzyme-linked immunosorbent assays and flow cytometry. PBMCs from patients on calcineurin inhibitors after liver transplantation produced less interleukin-6 (IL-6) and tumor necrosis factor α (TNFα) in response to TLR2 stimulation (IL-6: P=0.02; TNFα: P=0.01), TLR4 stimulation (IL-6: P=0.02; TNFα: P=0.01), and TLR7/8 stimulation (IL-6: P=0.02; TNFα: P=0.02), compared with healthy controls. Both CD56(bright) and CD56(dim) natural killer (NK) cells from patients on calcineurin inhibitors also produced less interferon-γ (IFNγ) with TLR7/8 stimulation compared with healthy controls (CD56(bright) : P=0.002; CD56(dim) : P=0.004). Similar findings were demonstrated in healthy PBMCs cultured with CYA (PBMCs: TLR2, IL-6: P=0.005; TLR4, IL-6: P=0.03, TNFα: P=0.03; TLR7/8, IL-6: P=0.02, TNFα: P=0.01; CD56(dim) NK cells: TLR7/8, IFNγ: P=0.03). TAC impaired TLR4-mediated IL-6 and TNFα production by PBMCs (IL-6; P = 0.02; TNFα P = 0.009). In conclusion, patients on calcineurin inhibitors had impaired inflammatory cytokine production in response to TLR2, TLR4, and TLR7/8 stimulation compared comparison with healthy controls. Importantly, TAC and CYA appear to have different effects on TLR signaling. Impaired TLR function has important repercussions for risk of infection, graft rejection, and disease recurrence after transplantation, and the different immunosuppressive profiles of CYA and TAC may guide the choice of therapy to improve disease outcomes.

Clinical outcome of HCV-related graft cirrhosis and prognostic value of hepatic venous pressure gradient

Hepatitis C virus (HCV) allograft cirrhosis may progress rapidly requiring re-transplantation but its course is little studied. We evaluated serially biopsied patients who developed HCV-related allograft cirrhosis. We assessed outcome of graft cirrhosis in 55 out of 234 consecutive patients and predictors of decompensation and mortality, including hepatic venous pressure gradient (HVPG) in 38. Allograft cirrhosis (Ishak stage 6, 60%; stage 5, 40%) was diagnosed between 12 and 172 months (median, 52) from transplantation; subsequent follow up was 22 (1-78) months. Faster development (<or=48 months) was associated with tacrolimus and nonuse of azathioprine and prednisolone. Decompensation occurred in 22% with a probability of not developing decompensation reaching 60% at 5 years. Survival among compensated patients was 77% at 5 years, but fell rapidly after decompensation (12% at 1 year). Decompensation and mortality were independently associated with HVPG >or= 10 mmHg, Child-Pugh score >or= 7, and albumin levels <or= 32 g/dl but not with fibrosis stage 5 or 6, HCV genotype (1b, 34%) or immunosuppression used after diagnosis of cirrhosis. In conclusion, Ishak stage 5 and 6 HCV-related cirrhosis have similar prognosis after liver transplantation. An HVPG >or= 10 mmHg, in addition to liver dysfunction, gives independent prognostic information prior to decompensation, allowing early relisting before prognosis becomes extremely poor.

Intrahepatic cholestasis after liver transplantation

Biochemical cholestasis after liver transplantation is common and often has no clinical significance if biliary anastomosis strictures and leaks have been excluded. There is no agreed upon definition for severe cholestasis, but it is associated with a worse mortality. There has been little evaluation on risk factors, but these include cryoprecipitate and platelet transfusion intraoperatively, nonidentical blood group, suboptimal graft appearance, inpatient status before transplant, and bacteremia within the first month. Associated causes considered as early (<6 months) include ischemia-reperfusion injury, primary nonfunction, small-for-size graft syndrome, infection, drugs and acute cellular rejection. Late causes include hepatic artery thrombosis, chronic rejection, biliary complications, recurrent viral and cholestatic disease, and posttransplant lymphoproliferative disorder.

Liver transplantation for hepatitis C

Hepatitis C virus (HCV) infection is the leading cause of endstage liver disease in Western and Asian countries. However, after liver transplantation, HCV recurs in virtually all patients, and estimated HCV-related graft cirrhosis at 5-year follow-up is 30%. Although immunosuppression accounts for a major part of the accelerated progression of HCV in the transplant population, the best immunosuppression for recipients with HCV that could avoid such complication remains unknown at present. Combination therapy of interferon and ribavirin is thought to be the most effective for the treatment or prophylaxis of HCV infection. However, who should be treated, when treatment should be initiated, and with what agent should patients with HCV infection be treated are still unknown. The current data on HCV recurrence in patients who have received either living- or deceased-donor liver transplantation are controversial, but they are, presumably, similar. Thus, to avoid HCV recurrence in living-donor liver transplantation, we have to take approaches similar to those used for patients receiving deceased-donor liver transplantation. Based on reports from major transplant centers around the world, we consider the best strategy for liver transplantation-related HCV infection is steroid-free immunosuppression and preemptive low-dose interferon and ribavirin combination therapy. Here we describe our experience with living-donor liver transplantion for patients with hepatitis C at Osaka University. There is a need for standardizing the treatment for HCV infection. This can only be achieved through collaborative work between various liver transplant centers worldwide.

HCV clearance and treatment outcome in genotype 1 HCV-monoinfected, HIV-coinfected and liver transplanted patients on peg-IFN-alpha-2b/ribavirin

BACKGROUND/AIMS

Differences in HCV-RNA clearance during therapy might explain the lower efficacy of peg-IFN/RBV in HIV/HCV-coinfection. There are limited data on HCV-RNA clearance and treatment outcomes in liver transplanted (LT) patients.

METHODS

To assess the rates of SVR and baseline predictors of failure after 48 weeks of weight-adjusted peg-IFN-alpha-2b/RBV in 120 patients with HCV genotype 1: 61 HCV-monoinfected, 40 HIV-coinfected and 19 LT-patients. Viral clearance was evaluated in patients completing 24 weeks of therapy (n=112, 93%).

RESULTS

SVR was significantly lower in HIV-coinfection than in HCV-monoinfection or LT (18 vs. 39 vs. 42%, P<0.02). By multivariate analysis, HIV-coinfection (OR 3.048, 95% CI 1.133-8.196; P=0.027), baseline HCV-RNA over 800,000 IU/ml (OR 2.800; 95% CI 1.121-6.993, P=0.027) and higher AST values (OR 1.009; 95% CI 1.001-1.018; P=0.028) were significantly associated to failure. Despite similar baseline HCV load (5.67 vs. 5.75 vs. 5.90 log10 IU/ml), HIV-coinfection showed significantly lower HCV-RNA decreases than HCV-monoinfection at weeks 4 (P=0.015), 12 (P=0.015) and 24 (P=0.0003), and than LT at weeks 12 (P=0.003) and 24 (P=0.023). 36/60 subjects (60%) reaching EVR by week 12 obtained SVR vs. 3/60 (5%) who did not.

CONCLUSIONS

HIV-coinfection was independently associated to treatment failure, and led to a significantly slower HCV-RNA clearance.

Immunosuppression and donor age with respect to severity of HCV recurrence after liver transplantation

In HCV cirrhotic patients after liver transplantation, survival and recurrence of HCV appears to be worsening in recent years. Donor age has been suggested as a cause. However, it is not clear if early and/or late mortality is affected and whether donor age is a key factor, as opposed to changes in immunosuppression. The aim of this study was to assess impact of donor age and other factors with respect to the severity of HCV recurrence posttransplant. A consecutive series of 193 HCV cirrhotic patients were transplanted with cadaveric donors, median age 41.5 years (13-73) and median follow-up of 38 months (1-155). Donor age and other factors were examined in a univariate/multivariate model for early/late survival, as well as fibrosis (grade 4 or more, Ishak score) with regular biopsies, 370 in total, from 1 year onwards. Results of the study indicated that donor age influenced only short-term (3 months) survival, with no significant effect on survival after 3 months. Known HCC independently adversely affected survival, as did the absence of maintenance azathioprine. Severe fibrosis (stage > or = 4) in 51 patients was related to neither donor age nor year of transplantation, but it was independently associated with combined biochemical/histological hepatitis flare (OR 2.9, 95% CI 1.76-4.9) whereas maintenance steroids were protective (OR 0.4, 95% CI 0.23-0.83). In conclusion, in this cohort donor age did not influence late mortality in HCV transplanted cirrhotic patients or development of severe fibrosis, which was related to absence of maintenance steroids and a hepatitis flare. Maintenance azathioprine gave survival advantage.

Characterization of the genome and structural proteins of hepatitis C virus resolved from infected human liver

In the absence of satisfactory cell culture systems for hepatitis C virus (HCV), virtually all that is known about the proteins of the virus has been learned by the study of recombinant proteins. Characterization of virus proteins from patients with HCV has been retarded by the low virus titre in blood and limited availability of infected tissue. Here, the authors have identified a primary infection in a liver transplanted into an immunodeficient patient with chronic HCV. The patient required re-transplant and the infected liver, removed 6 weeks after the initial transplant, had a very high titre of HCV, 5 x 10(9) International Units (IU) per gram of liver. The density distribution of HCV in iodixanol gradients showed a peak at 1.04 g x ml(-1) with 73 % of virus below 1.08 g x ml(-1). Full-length HCV RNA was detected by Northern blotting and the ratio between positive- and negative-strand HCV RNA was determined as 60. HCV was partially purified by precipitation with heparin/Mn(2+) and a single species of each of the three structural proteins, core, E1 and E2, was detected by Western blotting. The molecular mass of core was 20 kDa, which corresponds to the mature form from recombinant sources. The molecular mass of glycoprotein E1 was 31 kDa before and 21 kDa after deglycosylation with PNGase F or endoglycosidase H. Glycoprotein E2 was 62 kDa before and 36 kDa after deglycosylation, but E2-P7 was not detected. This was in contrast to recombinant sources of E2 which contain E2-P7.

Treatment strategies for hepatitis C: intervention prior to liver transplant, pre-emptively or after established disease

Cirrhosis secondary to chronic hepatitis C virus (HCV) infection accounts for most liver transplants performed in the United States and European transplant centers. Given the high prevalence of HCV infection in the general population, the lack of consistently effective antiviral therapy, and the eventual progression to cirrhosis of a subset of those infected, predictions for the future are that the number of patients in need of transplantation will increase in the coming decade. In addition, viral infection recurs nearly universally leading to the development of chronic HCV in most recipients and progression to cirrhosis after a median of 9 to 12 years in a significant proportion of these recipients.

Recent advances in liver transplantation

Advances in liver transplantation continue to evolve but are hampered by continued increasing shortages in donor organs. This has resulted in a high incidence of patients dying while on the United Network for Organ Sharing waiting list. Indeed, we continue to assess ways of expanding the donor pool by using marginal donors, living donor liver transplantation, split liver transplantation, domino transplantation, and hepatic support systems to prolong survival long enough for the patient to undergo liver transplantation. Changes in the liver allocation policy to reduce the number of people dying while waiting for an organ are discussed. Implementation of the model for end-stage liver disease allocation system should help alleviate the problem of increasing deaths of patients while on the waiting list. Recurrent disease, particularly recurrent hepatitis C, continues to be a major problem, and effective therapy is needed to prevent both progression of hepatitis C and recurrence in the graft and avoid retransplantation. The use of pegylated interferon in combination with ribavirin holds promise for improving the success in overcoming recurrent hepatitis C. Finally, advances in immunosuppression have reduced the incidence of acute cellular rejection and chronic rejection. However, these therapies have been fraught with metabolic complications that are now affecting quality of life and long-term survival. Tailoring immunosuppressive regimens to the individual patient is discussed.

Impact of immunosuppressive therapy on recurrence of hepatitis C

1. Approximately 10% to 25% of hepatitis C virus-infected recipients of liver allografts will develop cirrhosis within 5 years of transplantation; this acceleration of the natural history of hepatitis C is caused in part by immunosuppression. 2. Risk factors for aggressive recurrence, graft loss, and death are treated acute cellular rejection, methylprednisolone pulse therapy, and use of OKT3. There appears to be no consistent difference between cyclosporine and tacrolimus in their effects on hepatitis C. 3. The benefit of steroid withdrawal, although commonly practiced in transplant recipients with hepatitis C, has not been proven. 4. Mycophenolate mofetil may show synergistic antiviral properties when used with interferon; however, posttransplantation use has not been associated with consistent beneficial or deleterious effects. 5. Effects of other agents, such as sirolimus or interleukin-2-receptor antibodies, have not been adequately defined. Early reports suggest that disease activity may be more aggressive when these agents are constituents of the immunosuppressive regimen.

Utilization of acidophil bodies in the diagnosis of recurrent hepatitis C infection after orthotopic liver transplantation

BACKGROUND

The distinction between acute rejection and early recurrent hepatitis C infection (RHCV) in the setting of orthotopic liver transplantation is often difficult. In liver biopsies acidophil bodies and lobular hepatitis are used to suggest a diagnosis of RHCV over rejection, however, the reliability of this practice has not been established. Because portal tract changes in RHCV and rejection often overlap, we sought to determine whether the degree of hepatocyte acidophil body formation seen on liver biopsies could be used to distinguish between these two conditions.

METHODS

Quantification of acidophil bodies was performed on liver biopsies in orthotopic liver transplant patients with RHCV (n = 10), non-hepatitis C orthotopic liver transplant patients with uncomplicated rejection episodes (n = 10) and non-transplant patients with chronic hepatitis C infection (n = 10). Hematoxylin and Eosin stained slides from all three groups were randomized and tissue segments 1.0 cm in length and of variable width (0.04-0.13 cm) were examined at 200x magnification in a blinded fashion by two pathologists in order to quantify the number of acidophil bodies/cm(2). Lobular chronic inflammation was also graded on a 0-3+ scale.

RESULTS

Liver biopsies taken at the onset of RHCV exhibited 606 +/- 101 acidophil bodies/cm(2) (mean +/- standard error of mean, range 200-1390). These counts were significantly greater (P =.0061, paired 2-tailed t-test) than the 241 +/- 53 acidophil bodies/cm(2) (range 80-514) for acute rejection, and the 194 +/- 21 acidophil bodies/cm(2) (range 100-333) for non-liver transplant chronic hepatitis C infection (P =.0013). No difference in lobular inflammation between index RHCV and rejection biopsies was detected.

CONCLUSIONS

Although there is overlap, on average there are twice as many acidophil bodies in the initial stage of RHCV when compared with acute rejection (average of 55 per linear cm in RHCV versus 21 per linear cm for rejection). Lobular inflammation was not a reliable indicator of the initial onset of RHCV.

Advancing donor liver age and rapid fibrosis progression following transplantation for hepatitis C

BACKGROUND AND AIM

Cirrhosis with liver failure due to hepatitis C virus (HCV) infection is the most common indication for liver transplantation (LT). Reinfection of the transplanted liver by HCV is inevitable, and aggressive hepatitis with accelerated progression to graft cirrhosis may be observed. Of concern, recent reports suggest that the outcome of LT for HCV may have deteriorated in recent years. Determinants of rate of progression to cirrhosis in the immunocompetent non-transplant patient are well defined, and the most powerful determinant is patient age at the time of infection. Following LT for HCV, recipient age does not affect outcome of HCV reinfection. However, the impact of donor age on graft fibrosis progression rate following LT has not been examined.

METHODS

We have examined post-transplant biopsies to assess histological activity, including fibrosis stage (scored 0-6 units, 6 representing established cirrhosis), and to calculate fibrosis progression rates in 101 post-transplant specimens from 56 HCV infected LT patients. Univariate and multivariate analyses examined the impact of parameters including recipient and donor age and sex on fibrosis progression rate, and on predicted time to cirrhosis.

RESULTS

For the cohort, median fibrosis progression rate was 0.78 units/year, and median interval from transplantation to development of cirrhosis was 7.7 years. In multivariate analysis, donor age (not recipient age) was a powerful determinant (p=0.02) of fibrosis progression rate. When the liver donor was younger than 40 years, median progression rate was 0.6 units/year and interval to cirrhosis was 10 years. When the donor was aged 50 years or more, median progression rate was 2.7 units/year and interval to cirrhosis only 2.2 years. During the observation period there has been a significant increase in donor age (p=0.01) but date of transplantation per se is not a determinant of progression rate when included in multivariate analyses.

CONCLUSIONS

Donor age has a major influence on graft outcome following transplantation for HCV. The changing organ donor profile will affect the long term results of LT for HCV. These observations have important implications for donor liver allocation.

Impact of cytomegalovirus infection, year of transplantation, and donor age on outcomes after liver transplantation for hepatitis C

Recurrence of hepatitis C virus (HCV) infection after liver transplantation (LT) is almost universal. However, variables that hasten the progression of allograft injury have not been fully defined. Cytomegalovirus (CMV) is a common infection post-LT, and its impact on the course of post-LT HCV infection remains unclear. We investigated the impact of CMV infection on patient and graft outcomes in 93 consecutive HCV-infected liver transplant recipients. Data were collected prospectively, with surveillance cultures for CMV and protocol liver biopsies. CMV infection (defined as isolation of CMV from blood and treatment with ganciclovir) occurred in 25 patients (26.9%). Graft failure (defined as cirrhosis, relisting for LT, re-LT, or death) was significantly more common in CMV-positive compared with CMV-negative patients (52% v 19.1%; P =.002). Fibrosis stage 2 or greater on the 4-month liver biopsy specimen was more common in CMV-infected patients (45% v 16.4%; P =.01). Patients who underwent LT in more recent years had an increased risk for graft failure. Donor and recipient age, CMV infection, and mycophenolate mofetil use were significantly associated with graft failure in a stepwise multivariate analysis. CMV infection occurs in approximately one quarter of HCV-infected liver transplant recipients and is an independent risk factor for graft failure in these patients. Whether CMV mediates this by inducing increased immunosuppression or directly enhancing HCV replication requires further study.

Histological recurrence and progression of hepatitis C after orthotopic liver transplantation: influence of immunosuppressive regimens

Post-orthotopic liver transplantation (OLT) recurrence of hepatitis C is virtually universal, but histological progression of disease is not. This study examines long-term clinical and liver histological features at and after OLT to elucidate factors predictive of hepatitis C recurrence and progression after OLT. A blinded retrospective review of clinical, serological, and histopathologic features of 65 patients who underwent OLT for hepatitis C and Non A Non B hepatitis was conducted. Histological findings of recurrent hepatitis C and progression (fibrosis, >or= grade 2 by last follow-up) were correlated with clinical parameters. Histological recurrence of hepatitis C was seen in 43 of 65 patients, with progression in 19 patients. Histological findings in the native liver and post-OLT biopsy specimen at the time of recurrence showed no correlation with hepatitis C recurrence and progression. Patients treated with azathioprine (AZA)-containing immunosuppressive regimens experienced less recurrence (6 of 17 v 37 of 48 patients; P < .005) and progression (1 of 17 v 18 of 48 patients; P = .014) than those without AZA as part of their immunosuppressive regimen. No difference was seen between patients treated with cyclosporine versus those administered FK506 (P > .05). Histological recurrence of hepatitis C after OLT is seen in 66% of patients with progressive disease and 29% of all patients. The grade of inflammation in the native liver at the time of OLT and time of recurrence is not predictive of progression. AZA-containing regimens reduce histological recurrence and progression of hepatitis C in post-OLT patients.

The role of different immunosuppression in the long-term histological outcome of HCV reinfection after liver transplantation for HCV cirrhosis

BACKGROUND

The effect of the type of immunosuppression on the course of posttransplant hepatitis C virus (HCV) infection is unclear. The aim of this study was to evaluate the histological outcome of posttransplant HCV infection with respect to initial immunosuppressive therapy in a cohort of 59 of 65 HCV positive transplant patients who survived at least 12 months.

METHODS

Initial immunosuppressive therapy was triple (cyclosporine or tacrolimus and azathioprine and prednisolone) in 41, double (cyclosporine and prednisolone) in 5, and single (cyclosporine or tacrolimus) in 13 patients. There was blinded histological evaluation, based on necroinflammatory activity (grading score:0-18) and fibrosis (staging score: 0-6). The median histological follow-up was 36 (12-72) months.

RESULTS

In the last liver biopsy, high necroinflammatory activity indicating chronic hepatitis (grading score > or =4) was found in 42 (71%) and severe fibrosis or cirrhosis (staging score > or =4) in 18 (30.5%) patients. High necroinflammatory activity was associated significantly with absence of pretransplant alcohol abuse (P=0.01) and relatively with occurrence of posttransplant acute lobular hepatitis C (P=0.055). Development of severe fibrosis or cirrhosis was significantly associated only with the type of initial immunosuppressive therapy. In particular, severe fibrosis or cirrhosis developed significantly more frequently in patients treated with triple or double (17/46 or 37%) than with single initial immunosuppressive therapy (1/13 or 7.7%) (adjusted for biopsy time: P=0.045).

CONCLUSIONS

Severe fibrosis or cirrhosis appears to develop in 30% of HCV transplant patients in a median of 3 years and to be associated with heavier initial immunosuppression.

A randomized double-blind comparative study of mycophenolate mofetil and azathioprine in combination with cyclosporine and corticosteroids in primary liver transplant recipients

Acute hepatic allograft rejection occurs in approximately 50% to 60% of the patients undergoing liver transplantation. In this study, we compared the rate of acute rejection in liver transplant recipients randomized in a double-blind comparative study to treatment with mycophenolate mofetil (MMF) or azathioprine (AZA), both in combination with cyclosporine and corticosteroids. Five hundred sixty-five primary liver transplant recipients were randomly assigned to treatment with MMF, 1 g twice daily intravenously followed by 1.5 g twice daily orally (n = 278), or AZA, 1.0 to 2.0 mg/kg/d intravenously followed by oral administration (n = 287), in combination with cyclosporine and corticosteroids. Patients were followed up for at least 1 year, and efficacy analysis was based on intent-to-treat methods. Acute rejection was defined according to the Banff histological criteria. The two study groups were balanced for demographic and clinical baseline characteristics. The incidence of acute rejection or graft loss was 47.7% in the AZA patients and 38.5% in the MMF patients (P <.03). The incidence of biopsy-proven and treated rejection censoring for graft loss was 40.0% in the AZA group versus 31.0% in the MMF group (P <.06). Steroid-resistant rejection requiring treatment with either OKT3 or antithymocyte globulin occurred in 8.2% of AZA patients versus 3.8% in MMF patients (P <.02). Patient and graft survival rates at 1 year posttransplantation were 85.4% in the AZA group and 85.3% in the MMF group (P = not significant). MMF was superior to AZA in preventing acute rejection in the first 6 months posttransplantation. MMF and AZA were equivalent in preventing graft loss at 1 year, and the safety profiles between the two immunosuppressive agents were similar.

Daily interferon therapy for hepatitis C virus infection in liver transplant recipients

BACKGROUND

Hepatitis C virus infection persists after liver transplantation and causes recurrent liver injury in the majority of patients. Standard dose interferon therapy has been largely unsuccessful for hepatitis C in transplant recipients.

METHODS

Twelve patients, at least 7 months posttransplant, with detectable hepatitis C virus RNA in serum and features of hepatitis C on liver biopsy were randomized to interferon-alpha2a, 3 mU daily for 12 months (n=8) or no treatment (n=4). The tolerability of daily interferon dosing in liver transplant recipients was evaluated and effects on hepatitis C virus RNA level, quasispecies evolution, and liver histology were studied.

RESULTS

Treated patients had an improvement in histological activity index at the end of therapy relative to controls (median reduction of 2 versus median increase of 1.5) (P=0.04). Four treated patients had a virological response (all bDNA negative, one qualitative polymerase chain reaction negative) compared with none of the untreated patients. Only two of six treated patients tested had evidence of quasispecies diversification on therapy. Seven of eight patients in the treatment group required dose reduction for fatigue and/or depression. They tolerated 1.5 mU of interferon-alpha2a daily. Two treated patients developed graft dysfunction, one of who had histological evidence of rejection and subsequent graft loss.

CONCLUSIONS

Low daily doses of interferon were tolerated by liver transplant recipients and provided histological benefit without associated quasispecies diversification in most cases. These findings provide a rationale to study low dose daily or pegylated interferon maintenance therapy for the management of hepatitis C posttransplant.

The influence of cytomegalovirus viraemia on the outcome of recurrent hepatitis C after liver transplantation

BACKGROUND

Several interrelated host and hepatitis C virus (HCV) associated factors have been proposed to explain the variable outcomes in HCV recurrence. Recent evidence suggests that cytomegalovirus (CMV) infection not only is co-factor in progression of HCV recurrence but may precipitate allograft rejection. We investigated whether short-term CMV viremia influences HCV recurrence, the number and grade of acute rejection episodes, and the histological course of HCV recurrence during the first year after orthotopic liver transplantation (OLT) for HCV-related cirrhosis.

METHODS

A cohort of 39 patients transplanted for cirrhosis HCV-related was analyzed. Patients were evaluated twice weekly for CMV infection by a blood polymerase chain reaction (PCR) assay. Triple therapy with cyclosporine or tacrolimus, azathioprine and prednisolone was the initial immunosuppressive regimen. Preemptive treatment with ganciclovir was started when two consecutive PCRs for CMV were positive. Liver biopsies were performed on day 7 after OLT or when indicated. A 3-day IV 1 g methilprednisolone was given to patients with moderate or severe rejection. Ishak's score was used to grade inflammation and to stage fibrosis.

RESULTS

Neither CMV viremia nor CMV disease after OLT for HCV-related cirrhosis adversely influenced the incidence and grade of acute rejection episodes nor the histological outcome of post transplant HCV recurrence, during the first year after liver transplantation.

CONCLUSION

CMV viremia as detected by PCR does not affect the progression of HCV recurrence in liver grafts.

Posttransplantation prevention and treatment of recurrent hepatitis C

Hepatitic C virus (HCV) viremia is universal after orthotopic liver transplantation (OLT) for HCV cirrhosis. 2. At 5 years post-OLT, approximately 20% of patients have cirrhosis caused by recurrent hepatitis C. 3. Progression of disease is related to immunosuppression, immune response (CD4(+) lymphocytes), HCV genotype, and HCV quasispecies homogeneity. 4. Whether a therapeutic strategy of pre-OLT or early (preemptive) antiviral therapy is better than treating a clinically important hepatitis and the duration of treatment are not known. 5. Monotherapy with recombinant interferon-alpha or ribavirin is not useful in the long term. 6. Combination therapy (interferon and ribavirin) has given better results, but long-term data are not available. 7. HCV recurrence will benefit from randomized studies.

Pathology of the liver

At the close of the 20th century, a selection of articles published in 1999 with relevance to liver pathology reflects the wealth of technological and intellectual progress made during the span of the century. Immunohistochemical staining for hepatitis B virus antigens focused attention on a correlation between cytoplasmic expression of core antigen in individuals with precore mutants and higher activity of hepatitis. Infection of ducklings with a presurface mutant strain of duck hepatitis B virus produced cytopathic liver cell damage. Fibrosing cholestatic hepatitis, originally described as an unusual form of recurrent hepatitis B after liver transplantation, has now been described in hepatitis C virus-positive patients with renal transplants. It may be related to the emergence or selection of hepatitis C virus quasispecies. In biliary tract disease, researchers investigated the canal of Hering as a possible source of hepatic stem cells, sporadic mutations in the JAGGED1 gene (involved in cell differentiation) in Alagille syndrome, and several models of nonsuppurative destructive cholangitis. Further work was accomplished on nonalcoholic steatohepatitis, including a proposal of a grading and staging system as well as its detection in workers exposed to volatile petrochemicals. Among hepatic neoplasms and proliferative disorders, epithelioid hemangioendothelioma, angiomyolipoma and Langerhans' cell histiocytosis received coverage in articles describing the diagnostic pathology in collected series of patients.

Liver transplantation

Since the first human liver transplant done in 1963, the procedure has become a routine procedure with an excellent outcome in terms both of quality and of length of survival. The development and introduction into clinical practice of a variety of immunosuppressive agents has given the clinician a bewildering array of therapeutic options but with a lack of evidence on which to select for optimal immunosuppression. Tolerance can be reliably achieved in some animal transplants but remains to be achieved in humans. One of the major challenges facing the transplant community is the shortage of donor organs: imaginative approaches to overcome this problem include more effective use of marginal donor livers, splitting livers and development of living related transplants. While advances have been made in the field of xenotransplantation, there remain many hurdles to be overcome before this approach can be introduced into human transplantation. In the meanwhile, there are difficulties in determining the optimal criteria for listing patients for transplantation and for treating some of the complications arising after transplantation such as recurrence of disease and complications of immunosuppression, e.g. renal failure, malignancy and vascular disease.