Donor-recipient sharing of HLA class II alleles predicts earlier recurrence and accelerated progression of hepatitis C following liver transplantation

Increased Surgical Complications but Improved Overall Survival with Adult Living Donor Compared to Deceased Donor Liver Transplantation: A Systematic Review and Meta-Analysis

Background

Living donor liver transplantation (LDLT) provides an alternative to deceased donor liver transplantation (DDLT) for patients with end-stage liver disease in the circumstance of scarcity of deceased grafts. However, the outcomes of LDLT remain controversial.

Method

A systematic review and meta-analysis were performed to compare the outcomes of LDLT with DDLT. Twelve outcomes were assessed.

Results

Thirty-nine studies involving 38563 patients were included. LDLT was comparable in red blood cell transfusion, perioperative mortality, length of hospital stay, retransplantation rate, hepatitis C virus recurrence rate, and hepatocellular carcinoma recurrence rate with DDLT. Cold ischemia time was shorter and duration of recipient operation was longer in LDLT. Postoperative intra-abdominal bleeding rate occurred less frequently in LDLT recipients (odds ratio (OR) = 0.64, 95%confidence interval (CI) = 0.46 − 0.88, P = 0.006), but this did not decrease the perioperative mortality. LDLT was associated with significantly higher biliary (OR = 2.23, 95%CI = 1.59 − 3.13, P < 0.00001) and vascular (OR = 2.00, 95%CI = 1.31 − 3.07, P = 0.001) complication rates and better overall survival (OS) (1 year: OR = 1.32, 95%CI = 1.01 − 1.72, P = 0.04; 3 years: OR = 1.39, 95%CI = 1.14 − 1.69, P = 0.0010; and 5 years: OR = 1.33, 95%CI = 1.04 − 1.70, P = 0.02). According to subgroup analysis, biliary complication rate and OS improved dramatically as experience increased, while vascular complication rate could not be improved because it was mainly caused by the difference of the donor type itself.

Conclusions

LDLT remains a valuable option for patients in need of liver transplantation for it provides an excellent alternative to DDLT without compromising recipient outcomes. Further refinement in biliary and vascular reconstruction techniques and the accumulation of liver transplantation centers' experience are the key factors in expanding the application of LDLT.

Role of Human Leukocyte Antigen Compatibility in Graft Outcomes After Living Donor Liver Transplantation

PURPOSE

The influence of human leukocyte antigen (HLA) mismatch on liver transplantation has been widely studied, but is still controversial. The aim of this large single-center study was to analyze the role of HLA compatibility between donor and recipient in the graft outcomes of living donor liver transplantation (LDLT).

MATERIALS AND METHODS

A total of 925 recipients who had undergone LDLT between March 2001 and April 2012 were retrospectively analyzed. HLA typing was performed using a standard complement-dependent cytotoxicity technique. The degree and type of HLA-A, HLA-B, and HLA-DR mismatch were assessed. We also investigated the posttransplantation laboratory data, incidence of rejection, recurrence of hepatitis B virus (HBV), and graft survival as outcome parameters.

RESULTS

The type of HLA-A, HLA-B, and HLA-DR mismatch had no effect on rejection episodes, whereas the beneficial effect of a much lower degree (0-2) of HLA mismatch was notable. Recipients with 2 HLA-B mismatches or recipients with a higher degree of mismatch were associated with elevated bilirubin level, a higher recurrence rate of HBV, and inferior graft survival. A complete mismatch of 2 at the DR locus also decreased graft survival in LDLT recipients.

CONCLUSIONS

This study confirmed that the degree of HLA mismatch, as well as the locus-specific type of HLA mismatch, namely B and DR, play a major role in graft outcomes after LDLT. To obtain an improved graft outcome, HLA compatibility should be considered in the setting of LDLT, which provides sufficient time to select a more favorable donor-recipient combination.

Impact of alloimmune T cell responses on hepatitis C virus replication in liver transplant recipients

We investigated the influence of alloimmune T cell responses on hepatitis C virus (HCV) replication in HCV-infected patients after liver transplantation (LT). To monitor the immune-status in 27 HCV-infected LT recipients, we routinely performed mixed lymphocyte reaction (MLR) assays within 4 weeks after LT. HCV RNA titers in most patients fluctuated in inverse proportion to the stimulation index (SI) of anti-donor reactive T cells early after LT. Two weeks after LT, recipients with high HCV RNA titers (>1000 KIU/mL) displayed a significantly lower SI for anti-donor reactive T cells than recipients with low HCV RNA titers did (<1000 KIU/mL). An in vitro transwell assay mimicking the anatomical features of the interaction between HCV-infected hepatocytes and alloreactive T cells in allograft livers demonstrated that interferon (IFN)-γ was necessary to suppress HCV replication. This study proves the significant impact of alloimmune T cell responses on HCV replication in HCV-infected LT recipients.

Living donor vs. deceased donor liver transplantation for patients with hepatitis C virus-related diseases

BACKGROUND & AIMS

Living donor liver transplantation (LDLT) provides a timely alternative to deceased donor liver transplantation (DDLT) for patients with hepatitis C virus-related (HCV-related) diseases in the circumstances of severe organ dearth. However, the patient and graft outcomes, and recurrence of HCV after LDLT remain controversial. Here we sought to compare the post-transplant outcomes after LDLT and DDLT.

METHODS

A systematic review and meta-analysis were performed. PubMed/MEDLINE, EMBASE, and the Cochrane database were searched for eligible literatures. The major end points were patient survival, graft survival, recurrence rate, and acute rejection. The pooled odds ratio (OR) was calculated using random-effects model to synthesize the results. Heterogeneity and publication bias were quantitatively evaluated.

RESULTS

Fourteen studies with a total of 2024 participants were included in this analysis. We found comparable patient survival between groups (1-year: OR, 0.78, 95% CI, 0.48-1.26, p=0.31; 2-year: OR, 0.71, 95% CI, 0.41-1.23, p=0.23; 3-year: OR, 0.79, 95% CI, 0.5-1.12, p=0.18; 4-year: OR, 0.92, 95% CI, 0.43-1.95, p=0.83; 5-year: OR, 1.06, 95% CI, 0.53-2.14, p=0.86, respectively). Although 1- and 3-year graft survivals were inferior in LDLT, 2-, 4- and 5-year graft survivals were similar. HCV recurrence rates and acute rejection rates were equivalent.

CONCLUSIONS

LDLT was equivalent to DDLT in terms of patient survival, long-term graft survival, HCV recurrence, and acute rejection rates, with potentially lower short-term patient and graft survival.

HLA tissue typing has no effect on the outcome of patients undergoing a living-donor liver transplant: a single-center experience in Egypt

OBJECTIVES

To analyze the effect of human leukocyte antigen tissue typing on outcome of live-donor liver transplant.

MATERIALS AND METHODS

Fifty recipients underwent live-donor liver transplant in the Dar Al-Fouad Hospital in Egypt and were retrospectively evaluated. Patients were classified into 2 groups: those with human leukocyte antigen +ve, and those with human leukocyte antigen -ve and donors. Hepatitis C virus-related end-stage liver disease was the main indication for transplant. Demographic data, preoperative laboratory data, results of human leukocyte antigen tissue typing, Child score, model for end-stage liver disease score, graft/recipient weight-ratio, ischemia times, surgical complications, postoperative laboratory data, liver biopsy, immunosuppression, and pulse steroids were collected. Graft and patient survivals were studied using Kaplan-Meier curves.

RESULTS

The mean model end-stage liver disease score was 18 ± 3.61 in group 1 and 17.73 ± 3.72 in group 2, with no significant difference. Graft/recipient weight ratio, ischemia times, and postoperative complications showed P = NS. Cyclosporine and tacrolimus were used in 5/9, 8/41, and 4/9 in group 1, and 32/41 in group 2 (P = NS). Rejection and pulse steroids were reported in 3/9 and 12/41 of group 1, and 3/12 and 11/41 of group 2 (P = NS). Hepatitis C virus-recurrence was diagnosed in 5/9 of patients (55%) and 8/41 of patients (29.5%) in groups 1 and 2 (P < .05). No statistical difference was found regarding mortality; 5-year patient and graft survival was 35/50 (70% in group 1 [human leukocyte antigen +ve]), 7/9 (77.8%), and 28/41 in group 2 (68.3%) (human leukocyte antigen -ve).

CONCLUSIONS

Positive human leukocyte antigen typing before live-donor liver transplant has no effect on the incidence of postoperative complications, rejection episodes, and patient or graft survival. Recipients with positive human leukocyte antigen typing may have increased risk of hepatitis C virus-recurrence after live-donor liver transplant.

Hepatitis C recurrence after liver transplantation: has the human leukocyte antigen mismatching at individual loci a role?

BACKGROUND AND AIM

The objective of this 11-year cohort retrospective study conducted in adult patients with chronic hepatitis C virus (HCV) who underwent liver transplantation (LT) was to identify whether human leukocyte antigen (HLA) mismatching is associated with the recurrence of HCV and with the time to recurrence of HCV.

METHODS

Among the 181 patients (74% men; mean age: 54 years, range 25-71) who underwent a LT between 1995 and 2006 in the study center, 163 had relevant data in their medical chart documenting HCV recurrence, and 107 (65.64%) reported a histological evidence of HCV recurrence.

RESULTS

Survival was 78% at 5 years. There was no significant relationship between the total score of HLA-mismatches and the recurrence of HCV. Similarly, there was no significant relationship between the total score of HLA mismatches and the time to recurrence of HCV. For the analyses at each individual locus, a significant relationship between the individual scores of HLA-mismatches and the recurrence of HCV were observed. Out of the 40 patients who experienced a rejection, the rate of recurrence was not different according to the severity of the rejection (75% mild, 64% moderate and 64% for severe rejection).

CONCLUSIONS

In conclusion, this large study did not demonstrate any relationship between the total score of HLA mismatches and HCV-recurrence. Contrarily a significant relationship between the individual scores of HLA mismatches (HLA-A3, HLA-B35, HLA-DR3, HLA-DR7, HLA-DQ2, HLA-DQ2-0) and the recurrence of HCV were observed.

Approach to recurrent hepatitis C following liver transplantation

Hepatitis C-associated liver failure is the most common indication for liver transplantation. Histologic evidence of recurrence is apparent in approximately 50% of hepatitis C virus (HCV)-infected recipients in the first postoperative year. Approximately 10% of HCV-infected recipients will die or lose their allograft due to hepatitis C-associated allograft failure. HCV-infected recipients who undergo retransplantation have 5-year patient and graft survival rates that are broadly similar to those for transplant recipients who are not HCV infected. Although the choice of calcineurin inhibitor, mycophenolate mofetil, or both has not been clearly shown to affect histologic recurrence of hepatitis C, higher cumulative exposure to corticosteroids is associated with increased mortality and more severe histologic recurrence. In contrast to treatment of non-HCV-infected recipients, treatment of HCV-infected transplant recipients for acute cellular rejection is associated with attenuated patient survival. Steroid-resistant rejection with or without the use of T-cell-depleting therapies is associated with a greater than fivefold increased risk of mortality in HCV-infected liver transplant recipients. Pegylated interferon with or without ribavirin should be considered for treatment of recipients with histologically apparent recurrence of hepatitis C before total bilirubin exceeds 3 mg/dL. The role of hepatitis C immunoglobulin and new immunosuppressive agents in the management of hepatitis C after transplant continues to evolve.

Effect of nonviral factors on hepatitis C recurrence after liver transplantation

OBJECTIVE

Hepatitis C (HCV) is now the most common indication for orthotopic liver transplantation (OLT). While graft reinfection remains universal, progression to graft cirrhosis is highly variable. This study examined donor, recipient, and operative variables to identify factors that affect recurrence of HCV post-OLT to facilitate graft-recipient matching.

METHODS

Retrospective review of 307 patients who underwent OLT for HCV over a 10-year period at our center. Recurrence of HCV was identified by the presence of biochemical graft dysfunction and concurrent liver biopsy showing diagnostic pathologic features. Time to recurrence was the endpoint for statistical analysis. Five donor, 6 recipient, and 2 operative variables that may affect recurrence were analyzed by univariate comparison and Cox proportional hazard regression models.

RESULTS

Recurrence-free survival in the 307 study patients was 69% and 34% at 1 and 5 years, respectively. Four predictive variables related to either donor or recipient characteristics were identified. Advanced donor age, prolonged donor hospitalization, increasing recipient age, and elevated recipient MELD scores were found to increase the relative risk of HCV recurrence. Examination of HLA disparity between donors and recipients demonstrated no correlation between class I or class II mismatches and recurrence-free survival.

CONCLUSIONS

We have identified donor and recipient characteristics that significantly predict hepatitis C recurrence following liver transplantation. These factors are identifiable before transplant and, if considered when matching donors to HCV recipients, may decrease the incidence of HCV recurrence after OLT. A change in the current national liver allocation system would be needed to realize the full value of this benefit.

Influence of donor/recipient HLA-matching on outcome and recurrence of hepatitis C after liver transplantation

The aim of this study was to analyze the effect of human leukocyte antigen (HLA) matching on outcome, severity of recurrent hepatitis C and risk of rejection in hepatitis C positive patients after liver transplantation (LT). In a retrospective analysis, 165 liver transplants in patients positive for hepatitis C virus (HCV) with complete donor/recipient HLA typing were reviewed for recurrence of HCV and outcome. Follow-up ranged from 1 to 158 months (median, 74.5 months). Immunosuppression consisted of either cyclosporine-A- or tacrolimus-based quadruple induction therapy including or an interleukin 2-receptor antagonist. Protocol liver biopsies were performed after 1, 3, 5, 7, and 10 years and staged according to the Scheuer scoring system. The overall 1-, 5-, and 10-year graft survival figures were 81.8%, 69.11 and 62%, respectively. There was no correlation in the study population between number of HLA mismatches and graft survival. The number of rejection episodes increased significantly in patients with more HLA mismatches (P < 0.05). In contrast to this, the fibrosis progression was significantly faster in patients with 0-5 HLA mismatches compared to patients with a complete HLA mismatch. In conclusion, HLA matching did not influence graft survival in patients after LT for end-stage HCV infection, however, despite less rejection episodes, the fibrosis progression increased in patients with less HLA mismatches within the first year after LT.

HLA-DRB1 donor-recipient mismatch affects the outcome of hepatitis C disease recurrence after liver transplantation

BACKGROUND & AIMS

This study extends our previously reported observations that various immunological factors are associated with the occurrence of histologically proven recurrent hepatitis C. The two specific issues investigated were to confirm the associations of MHC alleles and donor/recipient mismatch with the occurrence of recurrent hepatitis C in an independent cohort of newly transplanted patients and to look for immunologic and nonimmunologic variables affecting the severity of the recurrent disease.

METHODS

Two separate cohorts of consecutive patients were studied: a look-back cohort (LC) of 120 patients and a cohort for studying the disease progression (CSDP) of 190 patients. Protocol liver biopsies were obtained at least 1, 3, 5, 7, and 10 years after liver transplantation (LT).

RESULTS

A fully mismatched donor/recipient pair at the DRB1 locus was confirmed to be associated with both the recurrence of histologic hepatitis in the LC (59% vs 23%, P = .0002) and its progression beyond stage 3 in the CSPD (71.4% vs 39.3%, P = .0003). Relevant immunologic and nonimmunologic variables were included into a multivariate Cox proportional model and three variables, namely, donor age, full HLA-DRB1 donor-recipient mismatch, and HLA B14, resulted in independent risk factors for the development of severe fibrosis.

CONCLUSION

This study provides evidence that DRB1 donor-recipient mismatch affects both the occurrence and progression of recurrent hepatitis C disease. This information is clinically relevant as it may help to better allocate organs and to recognize patients at risk for progression so that specific interventions can be implemented.

Factors differentially correlated with the outcome of liver transplantation in hcv+ and HCV- recipients

BACKGROUND

Survival following liver transplantation for hepatitis C virus (HCV) is significantly poorer than for liver transplants performed for other causes of chronic liver disease. The factors responsible for the inferior outcome in HCV+ recipients, and whether they differ from factors associated with survival in HCV- recipients, are unknown.

METHODS

The UNOS database was analyzed to identify factors associated with outcome in HCV+ and HCV- recipients. Kaplan-Meier graft and patient survival and Cox proportional hazards analysis were conducted on 13,026 liver transplants to identify the variables that were differentially associated with outcome survival in HCV- and HCV+ recipients.

RESULTS

Of the 13,026 recipients, 7386 (56.7%) were HCV- and 5640 were HCV+. In HCV- and HCV+ recipient populations, five-year patient survival rates were 83.5% vs. 74.6% (P<0.00001) and five-year graft survival rates 80.6% vs. 69.9% (P<0.00001), respectively. In a multivariate regression model, donor age and recipient creatinine were observed to be significant covariates in both groups, while donor race, cold ischemia time (CIT), female to male transplants, and recipient albumin were independent predictors of survival of HCV- recipients. In the HCV+ cohort, recipient race, warm ischemia time (WIT), and diabetes also independently predicted graft survival.

CONCLUSIONS

A number of parameters are differentially correlated with outcome in HCV- and HCV+ recipients of orthotopic liver transplantation. These findings may not only have practical implications in the selection and management of liver transplant patients, but also may shed new insight into the biology of HCV infection posttransplant.

Retransplantation for recurrent hepatitis C: positive aspects

1. The prevalence of retransplantation for hepatitis C (HCV) patients is stable (around 40%). 2. Survival models to predict outcome of retransplantation do not show that HCV is an independent variable with poor outcomes. 3. Using Model for End-Stage Liver Disease (MELD) scores from the United Network for Organ Sharing (UNOS) database from 1996-2002, retransplantation for HCV had similar outcomes to other causes of retransplantation. 4. Poorer outcomes were noted for retransplantation with MELD scores greater than 25. 5. Minimal survival thresholds need to be developed for retransplantation for all causes of retransplantation.

Living donor liver transplantation in patients with hepatitis C

1. Hepatitis C virus (HCV) is the most common indication for living donor liver transplantation (LDLT). 2. Preliminary evidence suggests that HCV may occur earlier and may be more severe in LDLT recipients. However, current data is inconclusive relative to the impact of recurrent HCV on patient and graft survival in LDLT recipients. 3. Potential mechanisms for differences in severity of HCV in LDLT recipients are discussed. 4. LDLT remains a viable treatment option for selected patients with HCV.

Natural history of hepatitis C and outcomes following liver transplantation

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

Living donor liver transplantation and hepatitis C

Preliminary results indicate that living donor liver transplantation patients infected with hepatitis C virus (HCV) develop earlier and more severe recurrence than their cadaveric counterparts. The mechanisms underlying this observation are unknown, but could include hepatic regeneration, differences in living donor liver transplantation recipient demographics, immune homology between donor and recipients, or other factors not previously considered. The optimum clinical approach is to only consider living donor liver transplantation in HCV-infected recipients as a life-saving procedure and to attempt to eradicate HCV before transplantation to prevent recurrent infection.

Outcome of liver transplantation for patients infected by hepatitis C, including those infected by genotype 4

Predictors of hepatitis C virus (HCV)-related liver disease posttransplantation are still unclear. The impact of HCV genotype on outcome of transplantation has been studied, but conclusions are not in agreement. The role of HCV genotype 4 on the result of liver transplantation requires further study. The aim of this study is to examine the outcome of liver transplantation for patients with HCV genotype-4 infection. The study group included 128 patients who underwent transplantation for HCV infection: 28 patients, genotype 1; 11 patients, genotype 2; 19 patients, genotype 3; and 32 patients, genotype 4. For 64 of 128 patients, genotype was known and an assessable histological specimen was available. Median interval from transplantation to biopsy was 1.92 years (range, 0.24 to 11.48 years). Twenty-six percent of HCV genotype-4 patients developed either severe fibrosis or cirrhosis versus 6.7% in the genotype non-4 group (P =.04). A statistically significant greater fibrosis progression rate was observed in genotype-4 than genotype non-4 patients. In univariate and multivariate analysis, rapid liver fibrosis was associated with the presence of HCV genotype-4 infection. In addition, donor and recipient age and graft warm ischemic time also were associated with rate of fibrosis progression. Five-year cumulative rates for the development of cirrhosis or severe liver fibrosis were 84% in genotype-4 and 24% in genotype non-4 patients (P =.02). Five-year survival rates for patients with genotypes 1, 2/3, and 4 were 72%, 80%, and 79%, respectively (P =.8). In conclusion, 5-year survival for patients who underwent transplantation for HCV genotype-4 infection was similar to that of genotype non-4 patients; however, more severe fibrosis and rapid fibrosis progression was observed after transplantation in patients with genotype-4 infection.

Immunosuppression in hepatitis B virus and hepatitis C virus transplants: special considerations

The management of the immunosuppression treatment must take account its consequences on viral replication. Such treatment operates on the emerging balance between the recurrence of the virus on the graft and the immune response of the host. Randomized and prospective trials are currently ongoing with the purpose of determining the opportunity and relevance of each immunosuppressive agent in the treatment. In HBV patients, good control of HBV reinfection by prophylactic strategies using HBIG, lamivudine, or both have decreased the impact of immunosuppression on HBV recurrence. In contrast, HCV recurrence is now a major problem. The mechanisms of viral recurrence need to be deepened thus requiring new studies. The absence of in vitro and in vivo systems to study HCV reinfection is a lack in the comprehension of the relation between HCV and immunosuppression. It will allow adapting the effectiveness of the immunosuppression treatment. The treatment's primary target is to avoid graft rejection, and its secondary objective is to limit the risk of viral recurrence.

The utility of marginal donors in liver transplantation

The shortage of organs has led centers to expand their criteria for the acceptance of marginal donors. The combination of multiple marginal factors seems to be additive on graft injury. In this review, the utility of various marginal donors in patients requiring liver transplantation will be described, including older donors, steatotic livers, non-heart-beating donors, donors with viral hepatitis, and donors with malignancies. The pathophysiology of the marginal donor will be discussed, along with strategies for minimizing the ischemia reperfusion injury experienced by these organs. Finally, new strategies for improving the function of the marginal/expanded donor liver will be reviewed.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Effects of immunosuppression and organ transplantation on the natural history and immunopathogenesis of hepatitis C virus infection

The hepatitis C virus (HCV) is recognized as the leading cause for parenterally transmitted hepatitis. It is characterized by a high propensity to chronicity. Several efforts have been directed towards understanding the natural history of chronic HCV infection and the immunopathogenic pathways involved in mediating liver injury in the non-immunosuppressed and immunosuppressed states. In the non-immunosuppressed setting, liver damage seems to be largely immune mediated. In contrast, in the non-immunosuppressed state, there are several other factors that may modify the natural course of the infection and play a role in mediating liver injury. In this review we will address the natural history, virological and immunological aspects of HCV infection. Also, the role played by immunosuppression and organ transplantation in modifying the course of the infection and the pathogenesis of liver injury will be discussed.

Hepatitis C-induced hepatic allograft injury is associated with a pretransplantation elevated viral replication rate

Hepatitis C virus (HCV) allograft infection after liver transplantation follows a variable but accelerated course compared with the nontransplantation population. Predictors of outcome and mechanisms of reinfection remain elusive. The accelerated HCV-induced allograft injury associated with a 10- to 20-fold increase in serum viral quantity posttransplantation was hypothesized to be the result of elevated intrahepatic viral replication rates. Patients (N = 23) with HCV-induced end-stage liver disease who underwent liver transplantation between October 1995 and December 1998 were prospectively studied. HCV-induced allograft injury was defined by posttransplantation persistent biochemical hepatitis or allograft fibrosis not explained by other diagnoses. Liver biopsies (N = 92) were obtained by protocol and when clinically indicated. Negative-strand HCV RNA (putative intermediate for replication) was detected by a strand-specific reverse-transcription polymerase chain reaction (RT-PCR) assay and semiquantatively compared with constitutively expressed 18S rRNA. Recipients with increased pretransplantation replication were at increased risk for the development of posttransplantation biochemical hepatitis (P =.03), an increased rate of allograft fibrosis (P =.006), and increased mortality rate (40.0% vs. 0.0%; P =.02). There was no correlation with quantities of genomic HCV RNA in the serum with relative intrahepatic viral replication either before or after liver transplantation. The relative rate of HCV replication within the allograft was not elevated in the posttransplantation period compared with that seen within the explanted liver. Accelerated allograft injury caused by HCV may be predicted by viral replication rates within the explanted liver. The stable intrahepatic replication rate after transplantation suggests that elevated serum viral loads are the result of decreased viral clearance, possibly secondary to immunosuppressive therapy.

Influence of immunogenetic background on the outcome of recurrent hepatitis C after liver transplantation

In immunocompetent patients, specific human leukocyte antigen (HLA) class II alleles have been associated with the severity of hepatitis C virus (HCV)-related disease, in particular, HLA-DRB1*11 has been found to exert a protective effect. The authors have analyzed the role of HLA class I and II alleles in determining the frequency, timing, and progression of histologically proven recurrent hepatitis C in 89 patients who underwent a liver transplant for HCV-related cirrhosis. In addition, the influence of HLA mismatch between donor and recipient, HCV genotype, and use of steroid pulses was also evaluated. Median patient follow up was 35 months (range 4-119). HLA-DRB1 typing was performed by genomic analysis in all cases. Liver biopsies were obtained routinely and at least at yearly intervals. Histologically proven recurrent hepatitis was observed in 46 patients (52%), 10 patients progressing to stage 5-6 fibrosis in most cases within 2 years after transplant. By univariate analysis, 3 variables, HLA-B14, HLA-DRB1*04, and HLA-DRB1 donor/recipient mismatch, showed a significant effect on time to recurrent hepatitis C disease. These parameters were included in a multivariate regression model along with HCV genotype, treatment with steroid pulses and DRB1*11. HLA-B14, HLA-DRB1*04, and HLA-DRB1 donor/recipient mismatch were confirmed to provide a significant and independent contribution to the risk of hepatitic disease recurrence. As for the severity of the disease, none of the 10 patients with stage 5-6 hepatitis carried the HLA-DRB1*11 allele, in line with what was observed in nontransplant subjects. Our results suggest that in posttransplant recurrent hepatitis C, immunogenetic factors are relevant in determining HCV infection outcome.

Recurrent hepatitis C after liver transplantation: clinical and therapeutical issues

Hepatitis C virus (HCV) reinfection after liver transplantation is almost constant, assessed by the persistence of HCV RNA in 90% of cases. Acute hepatitis appeared in 75% of patients at a median of 4 months' post-transplantation. The 5-year actuarial rate of acute and chronic hepatitis on the graft is 75% and 60%, respectively. The rate of HCV cirrhosis on the graft is variable from 8 to 25% at 5 years. After transplantation, HCV viraemia is dramatically increased and correlates with the occurrence of acute hepatitis on the graft. Intrahepatic levels of HCV are high at the time of acute hepatitis, and decrease with constitution of chronic graft hepatitis lesions, implying an immunological response to the viral infection. A relationship between genotype 1b and the prevalence of HCV hepatitis on the graft has been suggested in European but not American series. The influence of the age of the recipient, quasispecies, viral compartmentalization, immunosuppressive treatment, and of HLA matching is being evaluated. The 5-year patient survival is around 65-80%. However, the occurrence of cirrhosis with a risk of graft failure may decrease the 10 and 15-year patient survival. Attempts to give prophylactic post-transplant antiviral treatment are under evaluation. Antiviral treatment of post-transplant graft lesions with combination therapy interferon-ribavirin gave promising results but indications and duration of treatment should be evaluated. In conclusion, HCV reinfection is frequent, but medium-term survival is good. However, the long-term graft and patient survival remains unknown, and efficient prevention and treatment of HCV graft is mandatory.

Increased late hepatic artery thrombosis rate and decreased graft survival after liver transplants with zero cross-reactive group mismatches

The use of broad-specificity cross-reactive groups (CREGs) at the A and B HLA loci has been proposed as a means to improve both access and outcome for renal transplantation but has not yet been studied for liver transplantation. We retrospectively analyzed our results for all adult liver transplantations performed at our center between 1989 and 1996 for which HLA typing and complete 3-year follow-up data were available. Two hundred eight transplantations were studied, with a mean follow-up of 66 +/- 2 months (range, 36 to 110 months); A and B loci were converted to CREGs by the method of Rodey. Thirteen percent of the patients with 0 CREG mismatches had hepatic artery thrombosis versus 2% for those with 1 or more mismatches (odds ratio, 6.7; 95% confidence interval, 2.6 to 17.3 by univariate analysis; odds ratio, 3.5; 95% confidence interval, 1.1 to 11.7 by logistic regression analysis). These events occurred significantly later in the 0-CREG mismatch group (21 +/- 7 v 4 +/- 2 months posttransplantation; P =.04 by Student's t-test). Graft survival rates were significantly lower for patients with 0 CREG mismatches (56% v 68% at end of study; P =.05 by Cox-Mantel test). The number of CREG mismatches had no effect on the frequency of rejection, steroid-resistant rejection, or infectious complications, including cytomegalovirus. Neither total nor individual A, B, or DR HLA matching had an effect on outcome. There appears to be little evidence that intentional CREG matching would improve outcomes for liver transplantation and, under some circumstances, could be deleterious.

Recurrence of hepatitis C virus infection after liver transplantation

In patients transplanted for HCV cirrhosis, reinfection by the virus is constant. Medium-term survival is good but long-term occurrence of cirrhosis is likely to impair the long-term prognosis of these patients. Patients should be informed before transplantation of the spontaneous risk of HCV recurrence and of its consequences. As for hepatitis B in the last decade, new antiviral therapies and immunosuppressive approaches will certainly change the course of HCV after transplantation.