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Background/Aims: While hepatic stellate cells (HSC) are known to be key mediators of liver fibrosis, only little is known about their functional role in the innate immune system of the liver. Methods: To address this question, murine HSC were isolated from livers of C57BL/6J mice and human HSC were isolated from liver samples obtained from resections and liver explants. HSC were stimulated with Toll-like receptor (TLR) 1–9 ligands for 20h. Supernatants were harvested and used in virus protection assays (encephalomyocarditis virus, EMCV) as well as in human and murine hepatitis C virus (HCV) replicon systems. Expression of interferon (IFN), retinoic acid-inducible gene-I (RIG-I), and interferon-stimulated genes (ISGs) was assessed by quantitative reverse transcription polymerase chain reaction. Results: While all TLRs were detectable in HSC, in murine HSC only TLR 3 and -4 agonists could induce cytokines that had an antiviral effect upon EMCV and HCV replication. IFN-β was the main cytokine mediating the antiviral activity of TLR 3-stimulated HSC whereas other cytokines of undefined nature were involved in TLR 4-mediated antiviral effects. In human HSC, only TLR 3 stimulation led to production of antiviral cytokines. The antiviral effect was related to the up-regulation of ISGs and RIG-I in target cells. Conclusions: These data demonstrate that murine and human HSC have as yet unrecognized antiviral properties when activated through the TLR-system and TLR 3/HCV in particular. This sheds new light on their role in the innate immune system of the liver and their participation in the control of HCV replication. [Copyright &y& Elsevier]

Despite continuous high-risk behavior, a subgroup among people who inject drugs (PWID) remains seronegative for hepatitis C virus (HCV) suggesting that a state of "natural resistance" to HCV Infection may exist. Homozygosity for KIR2DL3 and its ligand HLA-C1 group alleles has been associated with control of HCV infection, however, the mechanism mediating this protective effect remained unclear. Methods Peripheral NK cells from PWID (n=104) were phenotypically and functionally characterized by multicolor flow cytometry. Expression levels of the NK cell receptor ligands were analysed in liver biopsies and primary human hepatocytes. Results HCV seronegative PWID (n=34) had increased levels of KIR2DL3+NKG2A− NK cells compared to healthy controls (n=10; p<0.001) and PWID with chronic (n=38; p<0.001) or resolved infection (n=37; p<0.001). There was an inverse correlation between the frequency of KIR2DL3+ and NKG2A+ NK cells (r=−0.53; p<0.0001). Importantly, expression of HLA-E, the ligand for NKG2A, was significantly upregulated in liver biopsies of HCV infected patients (n=51) compared to HBV infected patients (n=22; p<0.01) and correlated with HCV viral load (r=0.32; p<0.0029). In functional analyses KIR2DL3−NKG2A+ NK cells but not KIR2DL3+NKG2A− NK cells were significantly inhibited by HLA-E ligation. Accordingly, interferon gamma secretion of NK cells from PWID with chronic infection but not from HCV seronegative PWID was significantly suppressed in the presence of HLA-E. Conclusions KIR2DL3+NKG2A− NK cells are not sensitive to HLA-E-mediated inhibition and may thereby control early HCV infection prior to seroconversion and result in an apparent state of "natural resistance" to HCV in PWID. [ABSTRACT FROM AUTHOR]

Background: The fully automated and closed LIAISON®XL platform was developed for reliable detection of infection markers like hepatitis B virus (HBV) surface antigen (HBsAg), hepatitis C virus (HCV) antibodies (Ab) or human immunodeficiency virus (HIV)-Ag/Ab. To date, less is known about the diagnostic performance of this system in direct comparison to the common Abbott ARCHITECT® platform. Objectives: We compared the diagnostic performance and usability of the DiaSorin LIAISON®XL with the commonly used Abbott ARCHITECT® system. Study design: The qualitative performance of the above mentioned assays was compared in about 500 sera. Quantitative tests were performed for HBsAg-positive samples from patients under therapy (n =289) and in vitro expressed mutants (n =37). For HCV-Ab, a total number of 155 selected samples from patients chronically infected with different HCV genotypes were tested. Results: The concordance between both systems was 99.4% for HBsAg, 98.81% for HCV-Ab, and 99.6% for HIV-Ab/Ag. The quantitative LIAISON®XL murex HBsAg assay detected all mutants in comparable amounts to the HBsAg wild type and yielded highly reliable HBsAg kinetics in patients treated with antiviral drugs. Dilution experiments using the 2nd International Standard for HBsAg (WHO) showed a high accuracy of this test. HCV-Ab from patients infected with genotypes 1–3 were equally detected in both systems. Interestingly, S/CO levels of HCV-Ab from patients infected with genotype 3 seem to be relatively low using both systems. Conclusions: The LIAISON®XL platform proved to be an excellent system for diagnostics of HBV, HCV, and HIV with equal performance compared to the ARCHITECT® system. [ABSTRACT FROM AUTHOR]

Background/Aims: The aim of this study was to further elucidate the role of the IFN and the Toll-like receptor (TLR) system in the control of HCV replication by non-parenchymal liver cells (NPC). Methods: Murine HCV replicon bearing MH1 cells were incubated with supernatants from TLR1-9-stimulated murine NPC (Kupffer cells (KC), liver sinusoidal endothelial cells (LSEC)) and bone marrow-derived myeloid dendritic cells (mDC). HCV replication and expression of IFN-stimulated genes (ISGs) as well as TLR1-9 mRNA were determined by real-time rtPCR. Results: IFNs (-α, -β, -γ) and TLR3 ligands only (despite the expression of TLR1-7 and TLR9 mRNA) achieved direct suppression of HCV replication by about 80-90% or 60%, respectively. Supernatants from TLR3- and 4-stimulated NPC only, however, led to potent suppression of HCV replication through IFN-β and induction of ISGs. By contrast, mDCs could be stimulated by TLR2, -3, -4, -7 and -9 to produce antiviral cytokines. Conclusions: TLR3- and TLR4-stimulated NPC are able to regulate HCV replication through production of IFN-β. This can also, at least partly explain the high level of ISG expression in HCV infected livers. These novel findings are of particular relevance for the control of HCV replication by the innate immune system of the liver. [Copyright &y& Elsevier]