Hans Dieter Nischalke

A Polymorphism Near IL28B Is Associated With Spontaneous Clearance of Acute Hepatitis C Virus and Jaundice

BACKGROUND & AIMS A single nucleotide polymorphism (SNP) upstream of the IL28B gene has been associated with response of patients with chronic hepatitis C to therapy with pegylated interferon and ribavirin and also with spontaneous clearance of acute hepatitis C in a heterogeneous population. We analyzed the association between IL28B and the clinical presentation of acute hepatitis C virus (HCV) infection in a homogeneous population. METHODS We analyzed the SNP rs12979860 in 190 women from the German anti-D cohort (infected with HCV genotype 1b via contaminated rhesus prophylaxis) and its association with spontaneous clearance. Clinical data were available in 136 women with acute infection who were also evaluated for IL28B genotype. Based on results of a TaqMan polymerase chain reaction assay, the rs12979860 SNP genotypes studied were C/C, C/T, or T/T. RESULTS Spontaneous clearance was more common in patients with the C/C genotype (43/67; 64%) compared with C/T (22/90; 24%) or T/T (2/33; 6%) (P < .001). Jaundice during acute infection was more common among patients with C/C genotype (32.7%) than non-C/C patients (with C/T or T/T) (16.1%; P = .032). In C/C patients, jaundice during acute infection was not associated with an increased chance of spontaneous clearance (56.3%) compared with those without jaundice (60.6%). In contrast, in non-C/C patients, jaundice was associated with a higher likelihood of spontaneous clearance (42.9%) compared with those without jaundice (13.7%). CONCLUSIONS The SNP rs12979860 upstream of IL28B is associated with spontaneous clearance of HCV. Women with the C/T or T/T genotype who did not develop jaundice had a lower chance of spontaneous clearance of HCV infection.

The HLA-A2 Restricted T Cell Epitope HCV Core35–44 Stabilizes HLA-E Expression and Inhibits Cytolysis Mediated by Natural Killer Cells

Impaired activity of natural killer cells has been proposed as a mechanism contributing to viral persistence in hepatitis C virus (HCV) infection. Natural cytotoxicity is regulated by interactions of HLA-E with inhibitory CD94/NKG2A receptors on natural killer (NK) cells. Here, we studied whether HCV core encodes peptides that bind to HLA-E and inhibit natural cytotoxicity. We analyzed 30 HCV core-derived peptides. Peptide-induced stabilization of HLA-E expression was measured flow cytometrically after incubating HLA-E-transfected cells with peptides. NK cell function was studied with a (51)chromium-release-assay. Intrahepatic HLA-E expression was analyzed by an indirect immunoperoxidase technique and flow cytometry of isolated cells using a HLA-E-specific antibody. We identified peptide aa35-44, a well-characterized HLA-A2 restricted T cell epitope, as a peptide stabilizing HLA-E expression and thereby inhibiting NK cell-mediated lysis. Blocking experiments confirmed that this inhibitory effect of peptide aa35-44 on natural cytotoxicity was mediated via interactions between CD94/NKG2A receptors and enhanced HLA-E expression. In line with these in vitro data we found enhanced intrahepatic HLA-E expression on antigen-presenting cells in HCV-infected patients. Our data indicate the existence of T cell epitopes that can be recognized by HLA-A2 and HLA-E. This dual recognition may contribute to viral persistence in hepatitis C.

Association between the PNPLA3 (rs738409 C>G) variant and hepatocellular carcinoma: Evidence from a meta-analysis of individual participant data.

The incidence of hepatocellular carcinoma (HCC) is increasing in Western countries. Although several clinical factors have been identified, many individuals never develop HCC, suggesting a genetic susceptibility. However, to date, only a few single‐nucleotide polymorphisms have been reproducibly shown to be linked to HCC onset. A variant (rs738409 C>G, encoding for p.I148M) in the PNPLA3 gene is associated with liver damage in chronic liver diseases. Interestingly, several studies have reported that the minor rs738409[G] allele is more represented in HCC cases in chronic hepatitis C (CHC) and alcoholic liver disease (ALD). However, a significant association with HCC related to CHC has not been consistently observed, and the strength of the association between rs738409 and HCC remains unclear. We performed a meta‐analysis of individual participant data including 2,503 European patients with cirrhosis to assess the association between rs738409 and HCC, particularly in ALD and CHC. We found that rs738409 was strongly associated with overall HCC (odds ratio [OR] per G allele, additive model = 1.77; 95% confidence interval [CI]: 1.42‐2.19; P = 2.78 × 10−7). This association was more pronounced in ALD (OR = 2.20; 95% CI: 1.80‐2.67; P = 4.71 × 10−15) than in CHC patients (OR = 1.55; 95% CI: 1.03‐2.34; P = 3.52 × 10−2). After adjustment for age, sex, and body mass index, the variant remained strongly associated with HCC. Conclusion: Overall, these results suggest that rs738409 exerts a marked influence on hepatocarcinogenesis in patients with cirrhosis of European descent and provide a strong argument for performing further mechanistic studies to better understand the role of PNPLA3 in HCC development. (Hepatology 2014;59:2170–2177)

Interferon-lambda serum levels in hepatitis C

BACKGROUND & AIMS Dendritic cells (DCs) trigger adaptive immune responses and are an important source of antiviral cytokines. In hepatitis C virus (HCV) infection DC function is markedly impaired. Thus far, studies have focused on types I and II interferon (IFN). We studied IFN-lambda1 (IL-29) and IFN-lambda2/3 (IL-28A/B) serum levels in patients with different outcomes of HCV infection. METHODS IFN-lambdas were measured by ELISAs detecting IL-29 or IL-28A and IL-28B, respectively. Results were stratified with respect to the recently discovered rs12979860 T/C polymorphism upstream of the IL-28B gene. RESULTS In general IL-29 serum levels exceeded IL-28A/B at least twofold, with IL-29 and IL-28A/B levels being significantly higher in carriers of the rs12979860 C allele than in TT homozygous individuals (p<0.02). IL-29 levels were substantially lower in patients with chronic hepatitis C than in healthy controls (p=0.005) and patients with spontaneously resolved hepatitis (p=0.001). Patients with acute hepatitis C showed IL-29 levels intermediate between chronic hepatitis C and normal controls; and IL-29 serum levels were higher in patients who spontaneously resolved hepatitis C than in those who became chronic. In vitro HCV proteins NS3 and E2 directly inhibited IL-29 production in poly I:C-stimulated purified DCs. CONCLUSIONS Our data suggest that HCV proteins modify IFN-lambda production in DCs. Carriers of the rs12979860 C allele associated with resolution of HCV infection exhibited increased IFN-lambda levels. Moreover, high IFN-lambda levels predisposed to spontaneous resolution of HCV infection. Thus, IFN-lambdas seem to play an important role in the control of hepatitis C.

Oxidative damage is increased in human liver tissue adjacent to hepatocellular carcinoma

Accumulation of genetic alterations in hepatocarcinogenesis is closely associated with chronic inflammatory liver disease. 8‐oxo‐2′‐deoxyguanosine (8‐oxo‐dG), the major promutagenic DNA adduct caused by reactive oxygen species (ROS), leads to G:C → T:A transversions. These lesions can be enzymatically repaired mainly by human MutT homolog 1 (hMTH1), human 8‐oxo‐guanine DNA glycosylase (hOGG1) and human MutY homolog (hMYH). The aim of this study was to evaluate the extent of oxidative damage and its dependence on the cellular antioxidative capacity and the expression of specific DNA repair enzymes in tumor (tu) and corresponding adjacent nontumor (ntu) liver tissue of 23 patients with histologically confirmed hepatocellular carcinoma. 8‐oxo‐dG levels, as detected by high‐pressure liquid chromatography with electrochemical detection, were significantly (P = .003) elevated in ntu tissue (median, 129 fmol/μg DNA) as compared to tu tissue (median, 52 fmol/μg DNA), and were closely associated with inflammatory infiltration. In ntu tissue, the hepatic iron concentration and malondialdehyde levels were significantly (P = .001) higher as compared to tu tissue. Glutathione content, glutathione peroxidase activity and manganese superoxide dismutase messenger RNA (mRNA) expression did not show statistical differences between ntu and tu tissue. Real‐time reverse transcription polymerase chain reaction revealed in tu tissue significantly (P = .014) higher hMTH1 mRNA expression compared to ntu tissue. In contrast, hMYH mRNA expression was significantly (P < .05) higher in ntu tissue. No difference in hOGG1 mRNA expression was seen between tu and ntu. In conclusion, these data suggest that ROS generated by chronic inflammation contribute to human hepatocarcinogenesis. The role of DNA repair enzymes appears to be of reactive rather than causative manner. (HEPATOLOGY 2004;39:1663–1672.)

The PNPLA3 rs738409 148M/M Genotype Is a Risk Factor for Liver Cancer in Alcoholic Cirrhosis but Shows No or Weak Association in Hepatitis C Cirrhosis

Background An isoleucine>methionine mutation at position 148 in the PNPLA3 gene (p.I148M, rs738409) has recently been identified as a susceptibility factor for liver damage in steatohepatitis. Here, we studied whether the PNPLA3 rs738409 polymorphism also affects predisposition to hepatocellular carcinoma (HCC). Methods We compared distributions of PNPLA3 genotypes in 80 and 81 Caucasian patients with alcoholic and hepatitis C virus (HCV)-associated HCC to 80 and 81 age- and sex-matched patients with alcohol-related and HCV-related cirrhosis without HCC, respectively. PNPLA3 genotypes in 190 healthy individuals from the same population served as reference. Potential confounders obesity, diabetes, HCV genotype and HBV co-infection were controlled by univariate and multivariate logistic regression with forward variable selection. Results PNPLA3 genotypes were in Hardy-Weinberg equilibrium for all study groups. The frequency of the 148M allele was significantly (p<0.001) increased in alcoholic cirrhosis with (53.7%) and without HCC (36.2%) but was not different between healthy controls (22.9%) and patients with cirrhosis (25.3%; p = 0.545) and HCC (30.2%; p = 0.071) due to hepatitis C. HCC risk was highest in 148M/M homozygous patients with alcoholic liver disease (odds ratio (OR) 16.8 versus healthy controls; 95% confidence interval (CI) 6.68–42.43, p<0.001). Finally, multivariate regression confirmed 148M/M homozygosity (OR 2.8; 95%-CI: 1.24–6.42; p = 0.013) as HCC risk factor in alcoholic cirrhosis. In HCV-related cirrhosis only HCV genotype 1 was confirmed as a HCC risk factor (OR 4.2; 95%-CI: 1.50–11.52; p = 0.006). Conclusion The PNPLA3 148M variant is a prominent risk factor for HCC in patients with alcoholic cirrhosis, while its effects are negligible in patients with cirrhosis due to HCV. This polymorphism provides an useful tool to identify individuals with particularly high HCC risk in patients with alcoholic liver disease that should be taken into account in future HCC prevention studies.

A genome-wide association study confirms PNPLA3 and identifies TM6SF2 and MBOAT7 as risk loci for alcohol-related cirrhosis

Alcohol misuse is the leading cause of cirrhosis and the second most common indication for liver transplantation in the Western world. We performed a genome-wide association study for alcohol-related cirrhosis in individuals of European descent (712 cases and 1,426 controls) with subsequent validation in two independent European cohorts (1,148 cases and 922 controls). We identified variants in the MBOAT7 (P = 1.03 × 10−9) and TM6SF2 (P = 7.89 × 10−10) genes as new risk loci and confirmed rs738409 in PNPLA3 as an important risk locus for alcohol-related cirrhosis (P = 1.54 × 10−48) at a genome-wide level of significance. These three loci have a role in lipid processing, suggesting that lipid turnover is important in the pathogenesis of alcohol-related cirrhosis.

Hepatitis C virus E2 and CD81 interaction may be associated with altered trafficking of dendritic cells in chronic hepatitis C

Dendritic cells (DC) are crucially involved in the induction of immune responses; however, reports on DC functions in chronic hepatitis C are controversial. Function of DC includes proper cell trafficking between sites of infection and lympho‐cellular compartments. Thus, we analyzed DC compartmentalization and changes in DC migration in hepatitis C virus (HCV)‐infected patients. We found significantly lower numbers of circulating BDCA1+ and BDCA2+ DC in HCV(+) patients (n = 20) than in healthy controls (n = 12) (P < .05). Analyzing liver samples from HCV(+) patients (n = 15), HCV(−) controls (n = 15), and disease controls (n = 10), we demonstrated chronic hepatitis C to be associated with intrahepatic DC enrichment (P < .05). In vitro studies indicated that HCV E2‐induced secretion of RANTES efficiently attracts CCR5(+) immature DC. Incubation of DC with sera derived from HCV(+) patients made DC unresponsive to CCL21, the chemokine recruiting DC to lymphoid tissues for T cell priming. Unlike attraction of CCR5+ DCs via RANTES, direct inhibition of DC migration in response to CCL21 was specific for patients with chronic hepatitis C and could be attributed to interaction of HCV E2 with CD81 on DC. In conclusion, migration of DC is markedly affected by interaction of HCV E2 with CD81. Failure of DC to recirculate to lymphoid tissue may be critically involved in impaired T cell priming during HCV infection. (HEPATOLOGY 2006;44:945–954.)

Genetic variation in IL28B and treatment-induced clearance of hepatitis C virus in HIV-positive patients with acute and chronic hepatitis C.

Recently, a IL28B (rs 12979860) gene polymorphism was identified as a predictor for response to hepatitis C virus-specific treatment in human immunodeficiency virus (HIV)-uninfected and -infected patients with chronic hepatitis C. In an analysis of HIV-infected patients with acute hepatitis C, we found that the IL28B genotype was associated with serum levels of hepatitis C virus RNA, g-GT, and CD4 cell count. In contrast to HIV-infected patients with chronic hepatitis C, the IL28B genotype was not significantly associated with treatment response rates in patients with acute hepatitis C. Thus, effects of the IL28B single-nucleotide polymorphism may differ in HIV-infected patients with chronic and acute hepatitis C.

Induction of Interleukin-6 by Hepatitis C Virus Core Protein in Hepatitis C–Associated Mixed Cryoglobulinemia and B-Cell Non–Hodgkin's Lymphoma

Purpose: Chronic hepatitis C carries the risk to develop mixed cryoglobulinemia (MC) and B-cell non–Hodgkins lymphoma (B-NHL), possibly because viral antigens stimulate the hosts inflammatory response via extracellular pattern recognition receptors (PRR). To clarify this issue, we studied whether recognition of hepatitis C virus (HCV) proteins by PRR is involved in the pathogenesis of HCV-associated MC or B-NHL. Experimental Design: Peripheral blood mononuclear cells of patients with HCV-associated B-NHL (n = 12), MC (n = 14), uncomplicated hepatitis C (n = 12), and healthy volunteers (n = 12) were incubated with the recombinant HCV proteins E2, core, and NS3 to study induction of cytokine production, stimulation of B-cell proliferation, and immunoglobulin secretion. In addition, serum levels of interleukin-6 (IL-6) were measured by ELISA. Results: HCV core was the only studied protein, which induced production of IL-6 and IL-8 in CD14+ cells. IL-6 induction was mediated via Toll-like receptor 2 (TLR2) and lead to increased B-cell proliferation in vitro. TLR2 expression on monocytes and IL-6 serum concentrations were increased in all groups of HCV-infected patients compared with healthy controls and were highest in MC (P < 0.05). Conclusions: Increased secretion of IL-6 via stimulation of TLR2 by HCV core protein may play a role in the pathogenesis of hepatitis C–associated MC and B-NHL.