Enhanced apoptosis in post-liver transplant hepatitis C: Effects of virus and immunosuppressants

Acute exacerbation of hepatitis C in hepatocellular carcinoma patients receiving chemotherapy

Acute hepatitis C exacerbations can occur in cancer patients carrying hepatitis C virus (HCV) when receiving systemic chemotherapy. However, clinical studies evaluating these complications remain rare due to the lack of clinically proven effective and tolerable anti-HCV treatments at late cancer stages. Furthermore, no data were available regarding hepatitis C exacerbation in advanced hepatocellular carcinoma (HCC) patients receiving chemotherapy. To address this issue, 48 patients with HCV-related advanced HCC, who underwent systemic chemotherapy using 5- fluorouracil, cisplatin, and mitoxantrone from 2008 to 2014 were analyzed. Nine patients developed acute hepatitis exacerbations defined by HCV-RNA elevation ≥10-fold and alanine transaminase (ALT) elevation ≥5-fold of the upper normal limit. Six were genotype 1b and 3 were genotype 2. Three patterns of clinical courses were observed including single episode of exacerbation (n = 5), fluctuated flares (n = 3), and delayed exacerbation (n = 1). Hepatic failure developed in five patients. Patients with acute exacerbations were less likely to have pretreatment ascites (11.1% vs. 53.8%; P = 0.028) and displayed a lower baseline ALT (44.1 ± 28.5 U/L vs. 72.6 ± 19.2 U/L; P = 0.007). Paradoxically, despite a high risk of hepatic failure, occurrence of hepatitis C exacerbation was associated with a favorable overall survival (P = 0.027; 22.8 vs. 5.4 months). In conclusion, hepatitis C exacerbation can occur in HCC patients receiving chemotherapy, leading to liver failure. However, the flare was associated with a better overall survival, possibly due to its association with a better baseline liver function. J. Med. Virol. 89:153-160, 2017. © 2016 Wiley Periodicals, Inc.

NS5B induces up-regulation of the BH3-only protein, BIK, essential for the hepatitis C virus RNA replication and viral release

Hepatitis C virus (HCV) induces cytopathic effects in the form of hepatocytes apoptosis thought to be resulted from the interaction between viral proteins and host factors. Using pathway specific PCR array, we identified 9 apoptosis-related genes that are dysregulated during HCV infection, of which the BH3-only pro-apoptotic Bcl-2 family protein, BIK, was consistently up-regulated at the mRNA and protein levels. Depletion of BIK protected host cells from HCV-induced caspase-3/7 activation but not the inhibitory effect of HCV on cell viability. Furthermore, viral RNA replication and release were significantly suppressed in BIK-depleted cells and over-expression of the RNA-dependent RNA polymerase, NS5B, was able to induce BIK expression. Immunofluorescence and co-immunoprecipitation assays showed co-localization and interaction of BIK and NS5B, suggesting that BIK may be interacting with the HCV replication complex through NS5B. These results imply that BIK is essential for HCV replication and that NS5B is able to induce BIK expression.

Histopathological evaluation of recurrent hepatitis C after liver transplantation: A review

Although the morphological features of hepatitis C virus (HCV) recurrence after orthotopic liver transplantation (OLT) have been well established in the last decades, the differential diagnosis still represents a challenge for the pathologist, especially early recurrent hepatitis C vs mild acute cellular rejection. The present review focuses on the role of the pathologist and the pathology laboratory in the management of recipients with recurrent hepatitis C, the usefulness of early and late post-OLT liver biopsies, and the potential role of ancillary techniques (immunohistochemistry and reverse transcription-polymerase chain reaction, RT-PCR). The English literature on the topic is reviewed, focusing on the histopathology, the immunohistochemistry and the use of RT-PCR on HCV-positive post-OLT biopsies. The different histopathological illustrations of early and chronic recurrent hepatitis C are presented, with special focus on the main differential diagnoses and those features with prognostic relevance (cholestasis above all). The usefulness of ancillary techniques are discussed, especially HCV RNA quantitation by RT-PCR. Finally, the usefulness of long-term protocol biopsies is addressed: their usefulness for the study of allograft disease progression is clear, but their meaning in the long term is still debated. The significance of plasma cell infiltrate in HCV-positive allografts, the prognostic weight of graft steatosis, and the impact of donor age in recurrent hepatitis C also represent additional open issues.

Multi-step regulation of interferon induction by hepatitis C virus

Acute hepatitis C virus (HCV) infection evokes several distinct innate immune responses in host, but the virus usually propagates by circumventing these responses. Although a replication intermediate double-stranded RNA is produced in infected cells, type I interferon (IFN) induction and immediate cell death are largely blocked in infected cells. In vitro studies suggested that type I and III IFNs are mainly produced in HCV-infected hepatocytes if the MAVS pathway is functional, and dysfunction of this pathway may lead to cellular permissiveness to HCV replication and production. Cellular immunity, including natural killer cell activation and antigen-specific CD8 T-cell proliferation, occurs following innate immune activation in response to HCV, but is often ineffective for eradication of HCV. Constitutive dsRNA stimulation differs in output from type I IFN therapy, which has been an authentic therapy for patients with HCV. Host innate immune responses to HCV RNA/proteins may be associated with progressive hepatic fibrosis and carcinogenesis once persistent HCV infection is established in opposition to the IFN system. Hence, innate RNA sensing exerts pivotal functions against HCV genome replication and host pathogenesis through modulation of the IFN system. Molecules participating in the RIG-I and Toll-like receptor 3 pathways are the main targets for HCV, disabling the anti-viral functions of these IFN-inducing molecules. We discuss the mechanisms that abolish type I and type III IFN production in HCV-infected cells, which may contribute to understanding the mechanism of virus persistence and resistance to the IFN therapy.