Influence of immunosuppression on patient survival after liver transplantation for hepatitis C

Hepatic stellate cell activation in liver transplant patients with hepatitis C recurrence and in non-transplanted patients with chronic hepatitis C

The pathogenic mechanisms of accelerated graft fibrosis in hepatitis C recurrence after liver transplantation (LT) are not well established. The aim of the study was to assess whether a greater activation of hepatic stellate cells (HSC), the major collagen-producing cells in the liver, can occur in these patients as compared to non-LT patients with chronic hepatitis C. We determined the amount of activated HSC by computer-based morphometric analysis of alpha-smooth muscle actin (alphaSMA)-positive cells and the hepatic TGFbeta(1) expression by immunohistochemistry in 46 LT patients with hepatitis C recurrence, 35 non-LT patients with chronic hepatitis C, and 16 controls. Hepatic alphaSMA and TGFbeta(1) expression was higher in LT patients with hepatitis C recurrence than in controls and was correlated with fibrosis stage and progression rate. No significant difference in alphaSMA and TGFbeta(1) expression was observed between LT and non-LT patients with hepatitis C, with the exception of a higher transforming growth factor beta-1 (TGFbeta(1)) expression in non-LT patients in the early stages of fibrosis. LT patients receiving cyclosporine (CsA) or tacrolimus (FK) had a similar fibrosis progression rate and alphaSMA and TGFbeta(1) expression. In conclusion, the accelerated fibrosis observed in LT patients with hepatitis C recurrence does not seem to be related to a greater amount of activated HSC and TGFbeta(1) expression in the grafts of these patients as compared to non-LT patients with chronic hepatitis C. In LT patients, the amount of activated HSC and TGFbeta(1) expression correlated with fibrosis stage and progression, without any apparent influence of the type of calcineurin inhibitor administered.

Management of Recurrent Hepatitis C in Liver Transplant Recipients

Recurrent HCV infection is universal in liver transplant recipients who are viremic pretransplant. The rate of histologic disease progression after transplantation is more rapid, and the risk of cirrhosis by 5 to 10 years is about 30%. Several donor, recipient, and viral factors have been associated with worse post-transplant outcomes in recipients with recurrent hepatitis C. Whether or not HCV-infected recipients of live donor grafts have worse out-comes compared with deceased donor graft recipients is controversial. To maximize the long-term survival of recipients with HCV infection, eradication of infection is the ultimate goal. Treatment of recurrent HCV after liver transplantation can be undertaken at several different time points: (1) prophylactically, at the time of transplantation; (2) pre-emptively, in the early post-transplant period; and (3) after established recurrent histologic disease is present. Prophylactic therapy for HCV infection has no established role at present, but studies are ongoing. Preemptive therapy using IFN and RBV has resulted in variable SVR rates (9%-43%) and is generally poorly tolerated, especially if the patient has advanced liver disease pretransplantation. Treatment of established recurrent HCV disease with combination PEGIFN and RBV is associated with a SVR in about 30% to 35% of patients overall but is limited by high rates of dose reduction or drug discontinuation. In conclusion, successful HCV eradication in the post-transplant setting is difficult with current treatment options, but it is possible. Determination of the optimal doses of antiviral drugs in transplant patients and improvements in drug tolerability may be important first steps in achieving enhanced response rates. There is a need for new drugs in this population that have greater efficacy and a better safety profile.

Review article: hepatitis C virus and calcineurin inhibition after renal transplantation

The impact of hepatitis C virus on patient and graft survival after renal transplantation remains controversial. However, recent studies have given emphasis on the detrimental role of hepatitis C on long-term patient and graft survival after renal transplantation. Various mechanisms can promote the lower survival in hepatitis C virus-positive recipients, i.e. post-transplant diabetes mellitus, liver disease and infections. Novel evidence has been accumulated showing the inhibitory activity of ciclosporin on the hepatitis C virus replication rate in human hepatocytes; ciclosporin has been shown in vitro to suppress hepatitis C virus replication as effectively as interferon alpha. This effect has not been seen with tacrolimus and is separate from its immunosuppressive activity. Data from patients with normal kidney function or after bone marrow transplantation show that ciclosporin inhibits hepatitis C virus replication. It appears that the progression of liver fibrosis is slower in hepatitis C virus-positive liver transplant recipients treated with ciclosporin than tacrolimus. In contrast, the clinical outcome of hepatitis C in hepatitis C virus-positive patients after liver transplantation treated with ciclosporin vs. tacrolimus has given mixed results. No information after renal transplantation is available. Various parameters can promote the worsening of hepatitis C after renal transplantation but choice of calcineurin inhibition is one of the few risk factors that can potentially be modified by the physician. Prospective, comparative trials of ciclosporin and tacrolimus with large size and adequate follow-up after renal transplantation are in progress.

Treatment of recurrent hepatitis C after liver transplantation

Chronic hepatitis C virus (HCV) infection is the most common indication for liver transplantation in the United States and Europe, and more than 20,000 patients worldwide have undergone transplantation for complications of chronic hepatitis C. In North America, HCV accounts for 15% to 50% of the liver transplants performed in United States transplant programs. To maximize the long-term survival of liver transplant recipients who have HCV infection, eradication of infection is the ultimate goal. Pretransplant antiviral therapy with the goal of achieving viral eradication before transplantation is a consideration in some patients, especially those who have mildly decompensated liver disease. This article focuses on the management of liver transplant recipients who have HCV infection at the time of transplantation. Prophylactic and preemptive therapies, as well as treatment of established recurrent disease, are the strategies reviewed.

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.

Calcineurin inhibition and disease recurrence in the hepatitis C virus-positive liver transplant recipient

Development of hepatitis C virus (HCV)-related disease following liver transplantation is more aggressive than in non-transplant individuals, and accounts for approximately 10% of liver allograft failures. HCV disease progression appears to have accelerated in recent years, possibly due to the aging donor population and/or changing immunosuppression regimens, and survival among HCV-negative patients is falling. Various risk factors have been proposed for HCV disease recurrence, but choice of calcineurin inhibitor is one of the few that can potentially be modified by the physician. Cyclosporine (CsA) has been shown in vitro to suppress HCV replication as effectively as interferon alpha (IFN-alpha), an effect that is separate from the immunosuppressive activity of CsA. Data from bone marrow patients and non-transplant patient populations confirm that CsA inhibits HCV replication. This anti-HCV effect is not seen with tacrolimus. Histologically, there is evidence that progression of fibrosis in HCV-positive liver transplant patients may be slower with CsA than tacrolimus. The clinical implications of the anti-HCV effect of CsA require evaluation versus tacrolimus in a large-scale multicenter study.

Polymorphisms in cytokines and growth factor genes and their association with acute rejection and recurrence of hepatitis C virus disease in liver transplantation

Acute rejection (AR) and recurrence of hepatitis C virus (HCV) infection are complications after liver transplantation (LTx). Genetic factors play a role in cytokine production as a consequence of polymorphisms within cytokine genes. Our goal was to identify genetic factors that might be associated with AR and recurrence of HCV in liver transplant recipients (LTxRs). We studied 77 Caucasian LTxRs and 100 Caucasian healthy individuals. We studied single-nucleotide polymorphisms (SNPs) in tumor necrosis factor-alpha[TNF-alpha, interleukin-6 (IL-6), IL-10, transforming growth factor-beta1, and angiotensin-converting enzyme genes by SNaPSHOT trade mark Multiplex assay. SNPs were classified as high producers (HP), intermediate producers (IP), or low producers (LP), and their association with AR and recurrence of HCV were studied. The frequency of TNF-alpha IP and HP genotypes was significantly higher in LTxRs with AR in comparison to patients without AR (TNF-alpha HP -238: 63 vs 20%, p < 0.001; TNF-alpha HP -308: 47.4 vs 20%, p = 0.02). The frequency of IL-6 IP and HP genotypes was higher in patients with AR episodes, but the difference was not statistically significant (p = 0.14). However, when we analyzed the simultaneous presence of pro-inflammatory genotypes in the same patient, we found a significant difference between patients with and without AR, respectively (42.1 vs 14.6%, p = 0.012). Moreover, the frequency of the IL-10 LP genotype was higher in LTx patients with AR (p = 0.001) compared to patients without AR. There was an association between pro-inflammatory genotypes and HCV recurrence. Our data suggest that cytokine gene polymorphisms might play a role in AR and HCV recurrence in LTxRs.

Inhibitors of Calcineurin

Before the early 1980s, patient and allograft survival for solid organ transplant recipients was dismal. By 1983, the first calcineurin blocker, cyclosporine (Sandimmun), had been introduced, and outcomes were dramatically improved. However, cyclosporine macroemulsion had suboptimal pharmacokinetics, significant drug interactions, and several adverse effects, including nephrotoxicity, neurotoxicity, hyperlipidemia, and hypertension. Recent advances with cyclosporine include the introduction of modified dosage formulations: Neoral, a microemulsion, and several generic microemulsion products. The potent second-generation calcineurin blocker tacrolimus (Prograf) was introduced in 1994 and has become the drug of choice for several types of transplant recipients. Although tacrolimus has improved pharmacokinetics and therapeutic drugmonitoring parameters, it has adverse effects such as nephrotoxicity, neurotoxicity, and diabetes. Thus, current immunosuppressive regimens implementing calcineurin blockers often involve additional immunosuppressive agents to “spare” the use of these agents, minimizing their adverse effects. This article reviews the mechanisms of action, pharmacokinetics, clinical use, therapeutic drug monitoring, drug interactions, adverse effects, and dosing of cyclosporine and tacrolimus in solid organ transplant recipients.

Hepatitis C virus therapy, hepatocyte drug metabolism, and risk for acute cellular rejection

We recently reported on a series of patients who experienced acute cellular rejection (ACR) during the treatment of hepatitis C virus (HCV) infection in our posttransplantation cohort. Our hypothesis is that HCV clearance improves hepatic microsomal function, which in turn results in lower trough cyclosporine (CyA) and tacrolimus (TAC) levels, predisposing the patient to ACR. Records of all patients receiving transplants for HCV infection at our center from 1993 to June 2002 were reviewed. Two hundred three patients were identified. Thirty-seven patients (18%) were treated with interferon-based therapies in combination with ribavirin. Twelve patients were selected for analysis because they became HCV RNA negative during therapy, and 18 patients with no antiviral response were selected as controls (7 other patients had incomplete data or had switched from one immunosuppression [IS] therapy to the other). Baseline IS levels were compared with the first available level after documented negative HCV RNA results in the study group and the last on-treatment IS level in the control group. We also compared frequency and percentage of change in IS levels during therapy. Mean decline in CyA trough levels in the study group was from 187.28 ng/mL at baseline to 118.14 ng/mL immediately after becoming HCV RNA negative (-36.92%; P =.018). Mean decline in TAC levels was from 7.34 ng/mL at baseline to 5.02 ng/mL immediately after becoming HCV RNA negative (-29.17%; P =.044). Overall, 6 of 12 patients who cleared HCV RNA during therapy experienced ACR; 1 patient died as a result of ACR. Using percentage of decrease from baseline IS level, we combined results for patients administered CyA and TAC and found a significant decrease from baseline IS levels in responders (-31.8% after HCV RNA clearance on treatment; P =.0001). Nonresponders experienced a 0.98% decline in IS levels while on treatment, and the difference was significant compared with the change in the responder group (P =.006). A greater proportion of antiviral therapy responders also experienced trough IS levels 20% less than baseline than nonresponder controls during therapy (P =.0006). In conclusion, IS levels decreased significantly in patients responding favorably to anti-HCV therapy. This decrease in IS levels may have a key role in predisposing these patients to ACR.