The clinical and immunologic impact of using interferon and ribavirin in the immunosuppressed host

An escalating dose regimen of pegylated interferon and ribavirin in HCV cirrhotic patients referred for liver transplant

BACKGROUND

To lessen the severity of recurrent hepatitis C virus (HCV) postliver transplantation (post-LT) by treating HCV patients with cirrhosis, we assessed the safety and efficacy of an escalating dose pegylated interferon (PEG-IFN)/ribavirin protocol in pre-LT patients.

METHODS

Ninety patients were treated with 90 microg PEG-IFN alpha-2a and 400 mg ribavirin and advanced to 180 microg and 800 to 1200 mg, respectively, over 8 weeks.

RESULTS

Mean age was 55.3 years. Thirty-four percent of patients received prior interferon treatment, 77% had genotype 1 or 4. Mean Child's score was 6.7 and model for end-stage liver disease 11.2; 49% reached full-dose PEG-IFN and 85% ribavirin, 18% required dose reduction, 33% stopped treatment because of adverse effects, 9% had deterioration of liver function, and 7% died. Follow-up of 9.6 months showed sustained virological response in 13% of patients. The rate of serious complications was 16.3% in Child's class A, 48% in B, and 100% in C (P=0.005). Serum albumin was a significant predictor for worsening liver function (P=0.007).

CONCLUSIONS

Using an escalating dose regimen of PEG-IFN alpha-2a and ribavirin, we achieved only a 13% sustained virological response in HCV cirrhotic pre-LT patients with an accompanying 9% risk of worsening liver function and 7% risk of death.

Prevention of allograft tolerance by bacterial infection with Listeria monocytogenes

Exposure to certain viruses and parasites has been shown to prevent the induction of transplantation tolerance in mice via the generation of cross-reactive memory T cell responses or the induction of bystander activation. Bacterial infections are common in the perioperative period of solid organ allograft recipients in the clinic, and correlations between bacterial infections and acute allograft rejection have been reported. However, whether bacterial infections at the time of transplantation have any effect on the generation of transplantation tolerance remains to be established. We used the Gram-positive intracellular bacterium Listeria monocytogenes (LM) as a model pathogen because its effects on immune responses are well described. Perioperative LM infection prevented cardiac and skin allograft acceptance induced by anti-CD154 and donor-specific transfusion in mice. LM-mediated rejection was not due to the generation of cross-reactive T cells and was largely independent of signaling via MyD88, an adaptor for most TLRs, IL-1, and IL-18. Instead, transplant rejection following LM infection was dependent on the expression of the phagosome-lysing pore former listeriolysin O and on type I IFN receptor signaling. Our results indicate that bacterial exposure at the time of transplantation can antagonize tolerogenic regimens by enhancing alloantigen-specific immune responses independently of the generation of cross-reactive memory T cells.

Inflammation and repair in viral hepatitis C

Hepatitis C viral infection (HCV) results in liver damage leading to inflammation and fibrosis of the liver and increasing rates of hepatic decompensation and hepatocellular carcinoma (HCC). However, the host's immune response and viral determinants of liver disease progression are poorly understood. This review will address the determinants of liver injury in chronic HCV infection and the risk factors leading to rapid disease progression. We aim to better understand the factors that distinguish a relatively benign course of HCV from one with progression to cirrhosis. We will accomplish this task by discussion of three topics: (1) the role of cytokines in the adaptive immune response against the HCV infection; (2) the progression of fibrosis; and (3) the risk factors of co-morbidity with alcohol and human immunodeficiency virus (HIV) in HCV-infected individuals. Despite recent improvements in treating HCV infection using pegylated interferon alpha (PEGIFN-alpha) and ribavirin, about half of individuals infected with some genotypes, for example genotypes 1 and 4, will not respond to treatment or cannot be treated because of contraindications. This review will also aim to describe the importance of IFN-alpha-based therapies in HCV infection, ways of monitoring them, and associated complications.

Increased CD154 Expression in Uninfected Infants Born to HIV-Positive Mothers Exposed to Antiretroviral Prophylaxis

Although prevention of mother-to-child HIV transmission by antiretroviral drugs has been shown to be effective, the short- and long-term effects of treatment are not well known. Several reports suggest that antiretroviral drugs act not only by inhibiting viral replication, but also by improving antiviral immunity. In particular, treatment with nucleoside analogs was found to increase CD40 ligand (CD40L; CD154) levels, an inducible molecule expressed on activated T lymphocytes. The present study investigated potential immunostimulatory effects of antiretroviral treatment (ART) in uninfected HIV-exposed infants, receiving either ante- or postnatal therapy to reduce the transmission rate. To this end, we analyzed CD40L expression in unstimulated lymphocytes from peripheral blood samples of uninfected infants vertically exposed to HIV and subjected to ART. The CD45 PanLeucogating strategy was applied in flow cytometry to analyze the lymphocytes of 41 cases and 64 age-matched infants, taken as control. We found increased CD154 expression on both CD4+ and CD8+ lymphocytes in ART-treated infants, compared with the controls. CD154 was apparently functional, because the expression of CD86 on monocytes was enhanced; moreover, inhibition of the CD40-CD40L interaction produced downmodulation of CD86. From these results, we conclude that CD4+ and CD8+ lymphocytes of HIV-exposed noninfected infants, who have been exposed to antiretroviral drugs in fetal and early life, display enhanced CD154 expression and costimulatory activity.

Treatment of hepatitis C infection

HCV infection is one of the leading causes of chronic liver disease worldwide,and it results in cirrhosis, liver failure, and HCC. As a result, hepatitis C cirrhosis has become the principal indication for liver transplantation. Ironically,HCV infection can be cured with available antiviral therapies, but only a minority of infected persons has ever been treated. The current standard of therapy isa combination of PEG-IFNalpha and ribavirin, which produces high rates of SVRs(absence of detectable HCV RNA at least 24 weeks after cessation of therapy):42% to 56% in genotype 1 and 75% to 84% in genotypes 2 and 3. Recent reports indicate that the less frequent genotypes 4, 5, and 6 also are responsive to combination therapy. Recommendations for treatment of conventional and special patient populations were reviewed in detail. Newer therapeutics that are entering clinical trials provide hope that SVRs may be possible in patients who are difficult to treat and in nonresponders to current therapy.

Management of chronic Hepatitis C virus in patients with HIV

The life expectancy of HIV seropositive persons is approaching the life expectancy of those who are uninfected with HIV. Hepatitis C virus (HCV) infection has emerged as a worldwide epidemic. Given the similar transmission route between HCV and HIV, there has been an explosion in the number of individuals infected with both viruses. Because of the successful introduction of antiretroviral therapy, patients are more susceptible to new opportunistic infections such as HCV. HCV leads to a more rapid progression to end-stage liver disease in patients with HIV, and the morbidity and mortality related to HCV in co-infected patients is on the rise. Therefore, it has become imperative to treat both HIV and HCV in co-infected patients. The primary goal of HCV therapy is permanent eradication of the virus. Secondary goals include reduction in hepatic fibrosis progression, development of decompensated cirrhosis, and hepatocellular carcinoma. Early studies using standard interferon-alfa for the treatment of HCV in co-infected individuals were discouraging, as poor outcomes, high discontinuation rates, and severe adverse events were observed. The current standard of care for treatment of HCV is pegylated-interferon and ribavirin. New studies have recently demonstrated a higher sustained virologic response rate and a better adverse event profile than previously reported in co-infected patients. As a result, we recommend considering all co-infected patients for HCV therapy while watching closely for unique treatment-related toxicities. The treatment of HCV in co-infected patients should be a high priority for all providers.

Treatment of hepatitis C virus in HIV patients: a review

BACKGROUND

Survival in HIV infection has improved dramatically in the last decade due to antiretroviral therapy (ART). Due to shared routes of transmission, HCV is found in approximately 30% of HIV infected patients. HCV infection has emerged as a major issue in this population as manifest by a major increase in liver-related mortality. ART-associated hepatotoxicity has been demonstrated to occur more frequently in co-infected individuals and may be severe or fatal in some instances. Thus treatment of HCV has become a priority in HIV infected individuals.

OBJECTIVES

The main aims of this review are to summarise and illustrate the current evidence based management of anti-HCV therapy in HIV-infected patients.

METHODS

A systematic review of the literature was performed using Pubmed and Medline searches.

CONCLUSION

All HIV-infected patients should be screened for HCV infection via anti-HCV antibody and HCV RNA polymerase chain reaction. If HCV infection is present, treatment should be considered in those patients with evidence of liver inflammation and fibrosis. Recent studies have demonstrated the safety and efficacy of anti-HCV therapy in HIV-infected individuals with pegylated interferon and ribavirin combination therapy. HCV genotype is predictive of response to therapy and increasing the duration of therapy to 48 weeks has proven to be more effective in patients with genotypes 2 and 3. HCV treatment with interferon based therapy is associated with many unique side effects and toxicities in this population of which the clinician must be aware.

Effects of fish-derived lipoprotein extracts on activation markers, Fas expression and apoptosis in peripheral blood lymphocytes

Several factors may influence numbers and function of peripheral blood lymphocytes (PBLs) by different processes. We conducted this study to evaluate the effect of E-CAB-94011 and E-JUR-94013, two marine fish extracts from S. scombrus and T. trachurus, respectively, on in vitro PBLs activation and on the expression and functionality of Fas, a cell surface molecule that plays a central role in immune homeostasis and cytotoxic activity. PBLs from 24 healthy volunteers were isolated and flow cytometry was performed to measure the state of activation, Fas expression and apoptosis of PBLs. Functionality of Fas was tested by assessing apoptosis after incubation of isolated lymphocytes with agonistic anti-Fas antibodies in blood samples treated with both E-CAB-94011 and E-JUR-94013. Studies on the lymphocyte cell marker suggest a clear immune activation as measured by the increased levels of CD25, CD8, CD38, CD19 and HLA-DR in vitro expression on lymphocytes treated with both extracts. In addition, a significant reduction in the percentages of apoptotic CD19(+)CD38(+) double positive lymphocytes could be demonstrated in the treated samples with respect to controls (p<0.05). Therefore the present results indicate that both E-CAB-94011 and E-JUR-94013 in vitro are powerful immunoregulatory, increasing immune surveillance.

Living donor and split-liver transplants in hepatitis C recipients: does liver regeneration increase the risk for recurrence?

Concern exists that partial liver transplants (either a living donor [LD] or deceased donor [DD] in hepatitis C virus (HCV)-positive recipients may be associated with an increased risk for recurrence. From 1999 to 2003, at our institution, 51 HCV-positive recipients underwent liver transplants: 32 whole-liver (WL) transplants, 12 LD transplants and 7 DD split transplants. Donor characteristics differed in that WL donors were older, and LD livers had lower ischemic times. Recipient characteristics were similar except that mean MELD scores in LD recipients were lower (p < 0.05). With a mean follow-up of 28.3 months, 46 (90%) recipients are alive: three died from HCV recurrent liver disease and two from tumor recurrence. Based on 1-year protocol biopsies, the incidence of histologic recurrence in the three groups is as follows: WL, 81%; LD, 50% and DD split, 86% (p = 0.06 for LD versus WL). The mean grade of inflammation on the biopsy specimens was: WL, 1.31; LD, 0.33 and DD split, 1.2 (p = 0.002 for LD versus WL; p = 0.03 for LD versus DD split). Mean stage of fibrosis was: WL, 0.96; LD, 0.22 and DD split, 0.60 (p = 0.07 for LD versus WL). Liver regeneration does not seem to affect hepatitis C recurrence as much, perhaps, as factors such as DD status, donor age and cold ischemic time.

Hepatitis C etiology of liver disease is strongly associated with early acute rejection following liver transplantation

Although recurrent hepatitis C (HCV) occurs universally after liver transplantation (LT), its tempo and severity are variable and unpredictable. Diagnosis and treatment of early acute rejection (EAR) likely affect the course of recurrent HCV disease. We have studied a contemporary cohort of LT recipients to reexamine risk factors for EAR. We hypothesized that HCV etiology may represent a significant risk factor for EAR for many reasons. First, recurrent disease commonly causes biochemical abnormalities prompting allograft biopsy. Second, overlapping histologic features of acute rejection and recurrent HCV ambiguity may result in diagnostic ambiguity. Finally, the biology of hepatitis may precipitate an antidonor response in addition to an antiviral response. Records of 285 adult recipients undergoing primary LT for cirrhosis between January 1, 1999, and December 31, 2002, were retrospectively reviewed. EAR was defined as a biopsy-proven or an empirically treated episode within 6 months of LT. Cox proportional hazards analysis identified donor, recipient, transplant, and posttransplant characteristics associated with EAR; Kaplan-Meier analysis was used to assess rejection by etiology. HCV cirrhosis was the etiology for 51% of all LT recipients. There were 135 episodes of EAR (127 biopsy proven) in 117 recipients for an overall incidence of 41%. Patient groups with HCV and cholestatic / autoimmune disease groups exhibited the highest incidence of rejection at 49%. Recipient gender, ethnicity, etiology, LT year, and posttransplant immunosuppression levels were risk factors for EAR in univariate analysis; HCV etiology and female gender remained robust risk factors in multivariate analysis. Interferon-based therapy did not impact the incidence or timing of EAR. In conclusion, HCV etiology is strongly associated with EAR. HCV allograft reinfection may create an immunologic environment predisposed to EAR. Alternatively, the association of HCV and EAR may result from an increased frequency of allograft biopsy and may be further exacerbated by inability to accurately diagnose EAR in the setting of recurrent HCV.