Comprehensive phenotyping of regulatory T cells after liver transplantation.

Regulatory T cells (Tregs) play an important role in controlling alloreactivity after solid organ transplantation, but they may also impair antiviral immunity. We hypothesized that the Treg frequency and the Treg phenotype are altered in hepatitis C virus (HCV)-infected recipients of liver transplantation (LT) with possible prognostic implications. Tregs from 141 individuals, including healthy individuals, LT recipients with or without persistent HCV infections, and nontransplant patients with chronic HCV, were studied. A comprehensive phenotypic analysis was performed with multicolor flow cytometry, which included standard Treg markers [CD4(+), CD25(hi), CD127(-), and FoxP3(+) in addition to HLA DR, CCR7, CD45RA, CD62L, CD49d, CD39, ICOS and LAP-TGFß stainings. Healthy individuals and LT patients displayed similar Treg frequencies and largely comparable Treg phenotypes, which were stable over time after transplantation. In contrast, Tregs with a CD45RA(-) CCR7(-) effector phenotype were enriched in LT recipients with chronic HCV versus HCV-negative transplant patients. HCV infection, rather than LT, altered the expression of functional markers on Tregs. A principal component analysis revealed distinct Treg phenotypes in HCV-infected LT recipients with rejection and patients with recurrent graft HCV. In conclusion, Treg phenotypes are altered in HCV-infected LT patients. An investigation of Tregs may possibly help to distinguish recurrent HCV from graft rejection. Further functional studies are needed to define the role of Tregs in determining the balance between antiviral and allogenic immunity.

Interferon-alpha-induced TRAIL on natural killer cells is associated with control of hepatitis C virus infection.

BACKGROUND & AIMS: Pegylated interferon-alpha (PEG-IFNalpha), in combination with ribavirin, controls hepatitis C virus (HCV) infection in approximately 50% of patients by mechanisms that are not completely understood. Beside a direct antiviral effect, different immunomodulatory effects have been discussed. Natural killer (NK) cells might be associated with control of HCV infection. We examined the effects of IFNalpha on human NK cells and its relevance to HCV infection. METHODS: We performed gene expression profiling studies of NK cells following stimulation of peripheral blood mononuclear cells with IFNalpha. We evaluated IFNalpha-induced tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) expression using flow cytometry analyses of NK cells isolated from patients with acute or chronic hepatitis C that had received PEG-IFNalpha therapy. RESULTS: TRAIL was among the most up-regulated genes after IFNalpha stimulation of NK cells from healthy controls. After in vitro stimulation with IFNalpha, CD56(dim) NK cells from patients who had responded to PEG-IFNalpha therapy expressed higher levels of TRAIL than cells from patients with chronic hepatitis C. TRAIL expression, ex vivo, was inversely correlated with HCV-RNA levels during the early phase of PEG-IFNalpha therapy. In patients with acute hepatitis C, TRAIL expression on CD56(bright) NK cells increased significantly compared with cells from controls. In in vitro studies, IFNalpha-stimulated NK cells eliminated HCV-replicating hepatoma cells by a TRAIL-mediated mechanism. CONCLUSIONS: IFNalpha-induced expression of TRAIL on NK cells is associated with control of HCV infection; these observations might account for the second-phase decline in HCV-RNA levels during PEG-IFNalpha therapy.

Hepatitis E virus infection as a cause of graft hepatitis in liver transplant recipients.

Hepatitis E virus (HEV) infection induces self-limiting liver disease in immunocompetent individuals. Cases of chronic hepatitis E have recently been identified in organ transplant recipients. We questioned if chronic hepatitis E plays a role in graft hepatitis after liver transplantation in a low endemic area. Two hundred twenty-six liver transplant recipients, 129 nontransplanted patients with chronic liver disease, and 108 healthy controls were tested for HEV antibodies. HEV RNA was investigated in all sera from transplanted patients. HEV antibodies were detected in 1 healthy control (1%), 4 patients with chronic liver disease (3%), and 10 liver transplant recipients (4%). Three liver transplant patients also tested positive for HEV RNA. Two of them developed persistent viremia with HEV genotype 3. The patients were anti-HEV immunoglobulin G-negative and HEV RNA-negative before transplantation and had an episode of acute hepatitis 5 or 7 months after transplantation, which led to advanced liver fibrosis after 22 months in 1 patient. Seroconversion to anti-HEV occurred not before 4 months after the first detection of HEV RNA. The possibility of reverse zoonotic transmission was experimentally confirmed by the infection of 5 pigs with a patient's serum. The pigs showed histological inflammation in the liver, and HEV RNA was detectable in different organs, including muscle. In conclusion, the prevalence of HEV infection in Central European liver transplant recipients is low; however, chronic hepatitis E may occur and needs to be considered in the differential diagnosis of graft hepatitis. The diagnosis of HEV infection should be based on HEV RNA determination in immunosuppressed patients. We suggest that immunocompromised individuals should avoid eating uncooked meat and contact with possibly HEV-infected animals.

Comparison of low-dose pegylated interferon versus standard high-dose pegylated interferon in combination with ribavirin in patients with chronic hepatitis C with genotype 3: an Indian experience.

BACKGROUND AND AIMS: In chronic hepatitis C virus (HCV) infection with genotype 3, therapy with pegylated interferon (peg-IFN) alfa-2b in a dose of 1.5 mug/kg/week and ribavirin (800-1000 mg/day) is recommended for 24 weeks. Reduced doses of peg-IFN may increase compliance and decrease cost and adverse events. This study aimed to assess the safety and efficacy of two different regimens of peg-IFN alfa-2b, in combination with ribavirin, in genotype 3 patients. METHODS: A total of 103 liver biopsy-proven chronic HCV patients with genotype 3, having alanine aminotransferase levels >1.2 x ULN and positive HCV-RNA were randomized into two groups: group I (n = 76; age, 43.1 +/- 11.4 years; male/female, 67/9) received peg-IFN 1.0 mug/kg/week + ribavirin 10.6 mg/kg/day, while group II (n = 27; age, 37.3 +/- 11.6 years; male/female, 21/6) received peg-IFN 1.5 microg/kg/week + ribavirin 10.6 mg/kg/day. Patients in both groups were treated for 24 weeks. End of treatment viral response (ETVR) and sustained viral response (SVR) after a 6-month follow-up period were assessed. RESULTS: In both groups I and II, one patient was lost to follow-up, while one patient in group II withdrew due to side-effects. ETVR was seen in 72/76 (94.7%) of patients in the low dose group and 24/27 (88.9%) of patients in the high dose group (P = 0.375). SVR was seen in 60/76 (78.9%) of patients in the low dose group and 25/27 (92.6%) of patients in the high dose group (P = 0.145). Age (Pearson correlation coefficient = 0.263; P = 0.008) and fibrosis (correlation coefficient, 0.263; P = 0.008) showed a significant correlation with the SVR. CONCLUSION: In patients with genotype 3, peg-IFN at 1.0 microg/kg/week with ribavirin is as effective as peg-IFN at 1.5 mug/kg/week with ribavirin.