Fibrosing cholestatic hepatitis C after hematopoietic cell transplantation: report of 3 fatal cases.

Development of liver disease after hematopoietic cell transplantation is common and the causes diverse. Infection by hepatitis C virus (HCV) can be seen in patients who are chronically infected before transplant or from passage of virus from an infected donor; the normal 10-year course of hepatitis C after transplant is one of waxing and waning of serum aminotransferase enzymes, with little morbidity. In the series of 3 patients reported here, the course of hepatitis C was rapidly fatal, with the onset of jaundice at day 60 to 80 after transplant and liver histology typical of fibrosing cholestatic hepatitis (marked bile ductular proliferation, ballooned hepatocytes, and associated collagenous fibrosis centered around ductules). The bile ductular reaction pattern varied from elongated structures without a recognizable lumen to a pattern of cuboidal cells with a clear lumen. There was significant cholestasis with bile within hepatocytes and canalicular bile plugs. In situ HCV RNA hybridization studies from 1 patient showed a robust infection with high levels of HCV-infected hepatocytes and active viral replication. All 3 patients were on immunosuppressive drugs after transplant, including mycophenolate mofetil (MMF), which irreversibly inhibits inosine monophosphate dehydrogenase, on which T and B lymphocytes are dependent. We speculate that fatal fibrosing cholestatic hepatitis C in these cases was related to the immunosuppressive effects of MMF, as we had not recognized this presentation of HCV infection before the introduction of MMF.

Genetic and functional heterogeneity of the hepatitis C virus p7 ion channel during natural chronic infection.

The present study describes natural genetic heterogeneity of hepatitis C virus (HCV) p7 protein, the ion channel that plays a critical role in assembly and release of HCV, within 299 variants isolated from serum specimens of 27 chronically infected patients, 12 of whom with human immunodeficiency virus (HIV) co-infection. Liver fibrosis stage was inversely correlated with p7 synonymous substitutions (dS) (p=0.033), and indices of p7 genetic diversity were significantly higher in HIV-negative subjects compared to HIV-positive subjects (dS, p=0.005; non-synonymous substitutions (dN), p=0.002; dN/dS ratio, p=0.024; amino acid distances, p=0.007). Six p7 genes with naturally occurring unique amino acid variations were selected for in vitro study. The variants demonstrated diversified functional heterogeneity in vitro, with one variant from a subject with severe liver disease displaying hyperactive ion channel function, as well as other variants presenting altered pH-activated channel gating activities.

Hepatitis C virus induces oxidative stress, DNA damage and modulates the DNA repair enzyme NEIL1.

BACKGROUND AND AIMS: Hepatitis C virus (HCV)-induced chronic inflammation may induce oxidative stress which could compromise the repair of damaged DNA, rendering cells more susceptible to spontaneous or mutagen-induced alterations, the underlying cause of liver cirrhosis and hepatocellular carcinoma. In the current study we examined the induction of reactive oxygen species (ROS) resulting from HCV infection and evaluated its effect on the host DNA damage and repair machinery. METHODS: HCV infected human hepatoma cells were analyzed to determine (i) ROS, (ii) 8-oxoG and (iii) DNA glycosylases NEIL1, NEIL2, OGG1. Liver biopsies were analyzed for NEIL1. RESULTS: Human hepatoma cells infected with HCV JFH-1 showed 30-60-fold increases in ROS levels compared to uninfected cells. Levels of the oxidatively modified guanosine base 8-oxoguanine (8-oxoG) were significantly increased sixfold in the HCV-infected cells. Because DNA glycosylases are the enzymes that remove oxidized nucleotides, their expression in HCV-infected cells was analyzed. NEIL1 but not OGG1 or NEIL2 gene expression was impaired in HCV-infected cells. In accordance, we found reduced glycosylase (NEIL1-specific) activity in HCV-infected cells. The antioxidant N-acetyl cystein (NAC) efficiently reversed the NEIL1 repression by inhibiting ROS induction by HCV. NEIL1 expression was also partly restored when virus-infected cells were treated with interferon (IFN). HCV core and to a lesser extent NS3-4a and NS5A induced ROS, and downregulated NEIL1 expression. Liver biopsy specimens showed significant impairment of NEIL1 levels in HCV-infected patients with advanced liver disease compared to patients with no disease. CONCLUSION: Collectively, the data indicate that HCV induction of ROS and perturbation of NEIL1 expression may be mechanistically involved in progression of liver disease and suggest that antioxidant and antiviral therapies can reverse these deleterious effects of HCV in part by restoring function of the DNA repair enzyme/s.