Mark D. Berzsenyi

Differential expression of the CXCR3 ligands in chronic hepatitis C virus (HCV) infection and their modulation by HCV in vitro

ABSTRACT To investigate chemokine expression networks in chronic hepatitis C virus (HCV) infection, we used microarray analysis to determine chemokine expression in human infection and in chimpanzees experimentally infected with HCV. The CXCR3 chemokine family was highly expressed in both human and chimpanzee infection. CXCL10 was the only CXCR3 chemokine elevated in the serum, suggesting that it may neutralize any CXCR3 chemokine gradient established between the periphery and liver by CXCL11 and CXCL9. Thus, CXCR3 chemokines may not be responsible for recruitment of T lymphocytes but may play a role in positioning these cells within the liver. The importance of the CXCR3 chemokines, in particular CXCL11, was highlighted by replicating HCV (JFH-1) to selectively upregulate its expression in response to gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α). This selective upregulation was confirmed at the transcriptional level by using the CXCL11 promoter driving the luciferase reporter gene. This synergistic increase in expression was not a result of HCV protein expression but the nonspecific innate response to double-stranded RNA (dsRNA), as both in vitro-transcribed HCV RNA and the dsRNA analogue poly(I:C) increased CXCL11 expression and promoter activity. Furthermore, we show that CXCL11 is an IRF3 (interferon regulatory factor 3) response gene whose expression is selectively enhanced by IFN-γ and TNF-α. In conclusion, the CXCR3 chemokines are the most significantly expressed chemokines in chronic hepatitis C and most likely play a role in positioning T cells in the liver. Furthermore, HCV can selectively increase CXCL11 expression in response to IFN-γ and TNF-α stimulation that may play a role in the pathogenesis of HCV-related liver disease.

Chronic hepatitis C virus infection: genotyping and its clinical role

Chronic hepatitis C virus (HCV) infection is a worldwide public health problem with a global prevalence of 2%. A high proportion of those infected are at risk of developing cirrhosis and hepatocellular carcinoma and modeling data predicts that the burden of disease could soon increase substantially. The liver disease associated with chronic infection has led investigators to look for correlates between viral properties and disease progression, severity of disease and the response to antiviral therapy. HCV has been classified into six genotypes but genotype does not appear to influence disease presentation or severity of disease. However, genotype has been identified as a major predictor of response to interferon-based antiviral therapy. Antiviral regimens have been optimized for infections with HCV genotypes 1-4, although treatment strategies for genotypes 5 and 6 have yet to be developed. The molecular basis for the differences in response of HCV genotypes has yet to be determined.

Hepatic TLR2 & TLR4 expression correlates with hepatic inflammation and TNF-α in HCV & HCV/HIV infection.

Summary.  Signalling activated by Toll‐like receptors (TLRs) can result in the production of tumour necrosis factor alpha (TNF‐α) which is implicated in hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infection. No study has examined or compared hepatic expression of TLRs in both HCV and HCV/HIV. Liver and peripheral blood mononuclear cells (PBMCs) were obtained from HCV & HCV/HIV‐infected patients and PBMCs from HIV‐infected patients. Liver RNA was analysed by microarray and reverse transcription quantitative PCR (RT‐qPCR). PBMCs were analysed by flow cytometry. Associations with hepatic histology and infection type were sought. Forty‐six HCV, 20 HIV and 27 HCV/HIV‐infected patients were recruited. Increasing Metavir inflammatory activity score was associated with increased hepatic TLR mRNA by RT‐qPCR: TLR2 (P ≤ 0.001), TLR4 (P = 0.008) and TNF‐α (P ≤ 0.001). A high degree of correlation was seen between hepatic mRNA expression of TNF‐αvs TLR2 (r2 = 0.66, P < 0.0001) and TLR4 (r2 = 0.60, P < 0.0001). No differences in TLR gene or protein expression was observed between HCV, HCV/HIV‐ or HIV‐infected groups. Hepatic TLR2, TLR4 and TNF‐α mRNA are associated with hepatic inflammation in both HCV and HCV/HIV infection. High correlation between TNF‐α and TLR2/TLR4 suggests a role for the innate immune response in TNF‐α production. Activation of the innate immune response appears to be independent of infection type.

GB virus C genotype 2 predominance in a hepatitis C virus/HIV infected population associated with reduced liver disease.

Background and Aim:  GB virus C (GBV‐C) infection in hepatitis C virus (HCV)/HIV co‐infection is associated with a significant reduction in the severity of HCV‐related liver disease. The role of GBV‐C genotype in this association is unknown. It has been suggested that GBV‐C genotype may influence CD4 positive T‐cell counts in HCV/HIV co‐infected patients. The aim of the present study was to identify the GBV‐C genotype in a HCV/HIV co‐infected population and determine if the GBV‐C genotype contributes to a reduction in HCV‐related liver disease.

Down-regulation of intra-hepatic T-cell signaling associated with GB virus C in a HCV/HIV co-infected group with reduced liver disease

BACKGROUND & AIMS Studies have shown that GB virus C (GBV-C) infection leads to reduced liver disease in hepatitis C virus (HCV)/human immunodeficiency virus (HIV) co-infection. Considering that the underlying mechanism(s) are unknown, we aim to identify differential gene and protein expression associated with GBV-C in HCV/HIV co-infection that may be responsible for reduced liver disease. METHODS Liver, peripheral blood mononuclear cells (PBMCs), and plasma samples were collected from 43 HCV/HIV patients. Plasma was tested for GBV-C RNA by RT-PCR with NS5B gene primers. A microarray was performed on the liver and RT-qPCRs on the liver/PBMC samples. Hepatic protein expression was measured by immunohistochemistry. RESULTS Sixteen out of 43 patients had GBV-C RNA. GBV-C was associated with reduced hepatic fibrosis (p=0.005) and inflammation (p=0.007). The microarray analysis of the liver samples (n=10) showed down-regulation of genes critical to intra-hepatic T-cell signaling associated with GBV-C. Quantitative RT-PCR of the liver samples (n=13) confirmed the down-regulation of lymphocyte-specific protein tyrosine kinase (LCK) (p=0.02) and docking protein 2 (DOK2) (p=0.04). No differences in the expression levels of these genes were observed in PBMCs (n=22) according to the GBV-C status. The hepatic expression of the LCK protein, measured by immunohistochemistry (n=36), was decreased in CD3-positive T-cells within portal tracts associated with GBV-C (p=0.003). This remained significant in multivariate analysis controlling for hepatic fibrosis and inflammation (p=0.027). No differences were observed in plasma cytokine concentrations (n=25) or ex-vivo peripheral T-cell responses (n=13) versus GBV-C status. CONCLUSIONS GBV-C infection is associated with down-regulation of critical genes involved in intra-hepatic T-cell signaling in HCV/HIV co-infection. This may be relevant to the pathogenesis of reduced HCV-related liver disease in HIV co-infection.

What Is the Role of GB Virus C Infection in Hepatitis C Virus/HIV Coinfection?

Much has been published over the past 10 years regarding the influence of GB virus C (GBV-C) on HIV infection. Several studies have reported that coinfection with HIV and GBV-C leads to a more favorable outcome in patients with a delay in the development of AIDS compared with the outcome in patients infected with HIV alone. This has led some groups to look for the putative mechanism of this beneficial effect and alterations in the cellular immune response have been implicated. However there is still considerable controversy regarding this interaction because not all studies have shown a beneficial effect of GBV-C infection on the progression of HIV disease. By contrast there is no debate that GBV-C plays little role if any in hepatitis C virus (HCV) infection with no effect on the progression of HCV-related liver disease or on the effectiveness of interferon (IFN)--based therapy. Similarly there is no dispute that the course of liver disease is accelerated in patients with HCV/HIV coinfection. Indeed HCV related liver disease has been a significant cause of morbidity and mortality in HIV infected patients during the era of highly active antiretroviral therapy (HAART). This has stimulated increased interest in HCV therapy in HCV/HIV-coinfected subjects particularly given that HCV clearance rates of >40% are possible with combination pegylated (PEG)--IFN and ribavirin therapy. (excerpt)

Viral response guided therapy for hepatitis C in the approaching era of direct acting anti‐viral agents

azathioprine • Educate the patient and remind their General Practitioner about the interaction when prescribing azathioprine • Dose reduce azathioprine to 1/4 of the original dose when co-prescribing allopurinol and monitor the blood count frequently • Only co-prescribe azathioprine and allopurinol to improve azathioprine efficacy if thiopurine metabolites can be monitored. • Monitor blood count at least weekly for the first four weeks of co-prescription.

Spontaneous fungal peritonitis in a hemochromatotic patient with cirrhosis on long-term prophylactic antibiotics

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