Impact of IL28B genetic variation on HCV-induced liver fibrosis, inflammation, and steatosis: a meta-analysis

The impact of single-nucleotide polymorphisms on liver stiffness and controlled attenuation parameter in patients treated with direct-acting antiviral drugs for hepatitis C infection

Single-nucleotide polymorphisms (SNPs) of patatin-like phospholipase domain-containing 3 (PNPLA3), tolloid-like protein 1 (TLL1) and interleukin-28 (IL28) have been identified as susceptibility factors for liver steatosis, inflammation and fibrosis in patients with hepatitis C virus (HCV) infection. Here, whether these polymorphisms affected predispositions to changes in liver stiffness (LS) and controlled attenuation parameter (CAP) following direct-acting antiviral (DAA) therapy was assessed. The changes in LS and steatosis in 77 HCV-infected patients receiving DAA therapy were compared with PNPLA3, TLL1 and IL28 genotypes, using CAP, FibroScan and Virtual Touch tissue quantification (VTTQ) before treatment and 12 weeks after the end of the treatment. VTTQ results showed that LS significantly decreased in PNPLA3 CC (P=0.035), TLL1 AA (P=0.011) and IL28B TT (P=0.005) genotypes; no significant differences were observed in PNPLA3 CG/GG, TLL1 AT/TT and IL28B TG/GG. FibroScan results showed that LS significantly decreased in TLL1 AA (P=0.028) and IL28B TT (P=0.032), with no significant difference in PNPLA3 CC. No significant differences were observed in PNPLA3 CG/GG, TLL1 AT/TT and IL28B TG/GG groups. CAP was significantly increased in PNPLA3 CG/GG (P=0.039 and P<0.05) and IL28B TT (P=0.014); no significant difference was observed in PNPLA3 CC and all genotypes of TLL1 and IL28B TG/GG. Therefore, these results indicated that SNPs could predict changes in LS and steatosis after DAA therapy.

Interferon-λ rs12979860 genotype association with liver fibrosis in chronic hepatitis C (CHC) patients in the Pakistani population

Risk and progression of liver fibrosis and cirrhosis in chronic hepatitis C (CHC) patients is significantly influenced by host genetic factors in a polygenic manner. The rs12979860 genetic polymorphism in the interferon-λ3-interferon-λ4 (IFNL3-IFNL4) region has been found to be a major determinant of hepatic inflammatory and fibrotic progression in CHC patients of mainly Caucasian origin; however, it is not known if this association applies to other ethnicities, including Pakistani CHC patients. Here, we genotyped IFNL3-IFNL4 rs12979860 genetic variants in a sample set of 502 Pakistani patients with CHC and used logistic regression analysis to determine its association with the risk and progression of HCV-related fibrosis and cirrhosis. We demonstrate that the rs12979860 major (CC) genotype, despite not determining the risk of stage-specific hepatic fibrosis independently, is associated with a marginally significant risk of liver cirrhosis (OR: 1.64, p = 0.049) after an adjustment for age, gender, body mass index, HCV viral load, and liver enzymes. In a subgroup of CHC patients with sustained ALT levels of <60 IU/L, a more pronounced impact of the IFNL3-IFNL4 rs12979860 major (CC) genotype on advanced liver fibrosis (OR: 4.99, p = 0.017) and cirrhosis (OR: 3.34, p = 0.005) was seen. The present study suggests that IFNL3-IFNL4 rs12979860 polymorphism may also be a significant predictor of hepatic fibrosis and cirrhosis in Pakistani CHC patients, especially in those with normal or near-normal liver enzyme levels.

PNPLA3 and HLA-DQB1 polymorphisms are associated with hepatocellular carcinoma after hepatitis C virus eradication

BACKGROUND

Even though both interferon (IFN)-based and direct-acting antiviral (DAA) therapies against hepatitis C virus (HCV) reduce the risk of hepatocellular carcinoma (HCC), post-sustained virological response (SVR) patients remain at elevated risk of HCC.

METHODS

A total of 4620 patients who achieved SVR were enrolled in this retrospective cohort study. After excluding patients who had a history of HCC or developed HCC within 1 year and whose follow-up period was less than 1 year and who were positive for HBsAg, we investigated the association between clinical characteristics and HCC development after SVR in the remaining 3771 patients.

RESULTS

Median observation period was 41 months. We confirmed known risk factors. In addition, we found that PNPLA3 and HLA-DQB1 polymorphisms were associated with HCC after SVR. Finally, we propose an estimation model for the incidence of HCC after SVR. Based on gender, FIB-4 index, AFP, and PNPLA3 polymorphism, about 18% of all patients were classified as having high risk, with a cumulative incidence rate (CIR) at 5 years of 16.5%. Another 17% were classified as having moderate risk with a CIR of 7.6%. The remaining 65% showed a CIR of 0.5%. The effect of PNPLA3 polymorphism might be more pronounced in patients with lower body mass index (BMI) and without diabetes mellitus compared to those with higher BMI and diabetes mellitus.

CONCLUSIONS

We demonstrated that PNPLA3 and HLA-DQB1 polymorphisms were associated with HCC after SVR. These findings might be useful to inform risk stratification for HCC surveillance after SVR.

Human genetics of HCV infection phenotypes in the era of direct-acting antivirals

The recent introduction of direct-acting antivirals (DAAs) has revolutionized hepatitis C virus (HCV) therapy by improving virus eradication rates to over 90% in most patient groups. However, the impact of DAAs on global disease burden is currently limited, and a large number of chronically infected individuals remain at risk of developing liver complications, such as liver cirrhosis and hepatocellular carcinoma (HCC). The identification of patients at risk of liver complications and a greater understanding of the biological mechanisms involved in HCV disease progression might improve disease control. Recent genome-wide association and exome sequencing studies have identified several host genetic variants influencing the progression of liver fibrosis and the development of HCC associated with HCV infection and are reviewed here. Interestingly, some of the genetic variants associated with those HCV-associated liver complications were also associated with the clinical course of non-viral chronic hepatitis. Future challenges include the incorporation of this genetic information into clinical risk models for personalized disease management and the study of emerging phenotypes such as liver fibrosis regression and HCC development after HCV eradication.

Hepatic steatosis in chronic hepatitis B: a study of metabolic and genetic factors

Hepatic steatosis is a common finding in liver biopsy and may co-exist with chronic hepatitis B (CHB) infection. The aims of this study were to determine the prevalence of steatosis in CHB patients among Filipinos; determine the factors related to the presence of steatosis among individuals with and without CHB infection; and to investigate the possible association between steatosis and polymorphism in interleukin 28B (IL28B) gene. The presence of steatosis was correlated with clinical, biochemical and histological parameters. Peripheral blood samples of CHB patients with steatosis, CHB patients without steatosis and normal controls were genotyped for IL28B rs8099917 T>G using the TaqMan assay. Of the 46 CHB patients, 41% (19/46) had steatosis. Body mass index (BMI), fasting blood sugar (FBS), lipid profile and alanine transaminase levels were observed to be significantly different between CHB patients with steatosis and normal controls. The serum FBS of CHB patients with steatosis was significantly higher than patients without steatosis. High density lipoprotein cholesterol of patients without steatosis was significantly higher than patients with steatosis. Although not statistically significant, BMI, triglycerides, low density lipoprotein cholesterol and histology activity index in CHB patients with steatosis were found to be higher than those without steatosis. There was no significant association between the stage of fibrosis and severity of steatosis. In conclusion, the prevalence of hepatic steatosis among Filipino patients with CHB is 41%. Steatosis in CHB patients was associated with metabolic factors such as diabetes and dyslipidemia. IL28B rs8099917 T>G polymorphism is not associated with steatosis.

Data Mining and Machine Learning Algorithms Using IL28B Genotype and Biochemical Markers Best Predicted Advanced Liver Fibrosis in Chronic Hepatitis C

IL28B single nucleotide polymorphism (rs12979860) is an etiology-independent predictor of hepatitis C virus (HCV)-related hepatic fibrosis. Data mining is a method of predictive analysis which can explore tremendous volumes of information from health records to discover hidden patterns and relationships. The current study aims to evaluate and compare the prediction accuracy of scoring system like aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis-4 (FIB-4) index versus data mining for the prediction of HCV-related advanced fibrosis. This retrospective study included 427 patients with chronic hepatitis C. We used data mining analysis to construct a decision tree by reduced error (REP) technique, followed by Auto-WEKA tool to select the best classifier out of 39 algorithms to predict advanced fibrosis. APRI and FIB-4 had sensitivity-specificity parameters of 0.523-0.831 and 0.415-0.917, respectively. REPTree algorithm was able to predict advanced fibrosis with sensitivity of 0.749, specificity of 0.729, and receiver operating characteristic (ROC) area of 0.796. Out of the 16 attributes, IL28B genotype was selected by the REPTree as the best predictor for advanced fibrosis. Using Auto-WEKA, the multilayer perceptron (MLP) neural model was selected as the best predictive algorithm with sensitivity of 0.825, specificity of 0.811, and ROC area of 0.880. Thus, MLP is better than APRI, FIB-4, and REPTree for predicting advanced fibrosis for patients with chronic hepatitis C.

Triplex High-Resolution Melting Assay for the Simultaneous Assessment of IFNL3 rs12979860, ABCB11 rs2287622, and RNF7 rs16851720 Genotypes in Chronic Hepatitis C Patients

Chronic hepatitis C (CHC) is a leading cause of liver disease. Despite the improved efficacy of new antivirals, their high costs preclude their adoption in resource-limited settings, where CHC prevalence is highest. We developed a triplex high-resolution melting assay for the simultaneous assessment of three genetic polymorphisms related to the response to treatment and development of advanced fibrosis in CHC: IFNL3 rs12979860, ABCB11 rs2287622, and RNF7 rs16851720. We validated the assay in clinical samples from 130 CHC patients treated with classic therapy. The assay showed excellent reproducibility and 100% accuracy, sensitivity, and specificity against the gold standard Sanger sequencing. When added to routine examination data, genotype information significantly improved their performance for prediction of advanced liver fibrosis and sustained virological response (P = 0.041 and P = 0.011, respectively). Correspondingly, the full models had area under the receiver operating characteristic curve values of 0.842 (95% CI, 0.773-0.911) and 0.921 (95% CI, 0.870-0.972) and integrated discrimination improvements of 7.5% (95% CI, 2.5%-12.5%; P = 0.003) and 11.5% (95% CI, 5.8%-17.2%; P < 0.001), respectively. This is the first report on a diagnostic test for simultaneous genotyping of IFNL3, ABCB11, and RNF7 in CHC patients. Reliable and inexpensive, the assay should provide useful information for the clinical management of CHC, like identification of patients at risk of rapid disease progression or with high chances of response to classic therapy.

Association of IFNL3 Genotype with Hepatic Steatosis in Chronic Hepatitis C Patients Treated with Peginterferon and Ribavirin Combination Therapy

BACKGROUND

Genetic variation near the interferon lambda 3 (IFNL3) is known to be associated with response to pegylated interferon (pegIFN) and ribavirin combination therapy in patients with chronic hepatitis C virus (HCV) infection which is often accompanied by hepatic steatosis.

AIMS

We examined whether this genetic variation is associated with host lipids and treatment response.

METHODS

A total of 101 Japanese patients who had underwent liver biopsy before treatment with pegIFN and ribavirin for HCV genotype 1b infection were retrospectively analyzed for association between IFNL3 genotypes (rs8099917) and clinical factors including histopathological features of the liver. The presence of >5% steatosis in the liver specimen was defined as hepatic steatosis.

RESULTS

Forty patients (40%) had liver steatosis before therapy. Patients with IFNL3 minor genotype (non-TT) showed lower low-density lipoprotein cholesterol level (p=0.0045), higher γ-glutamyl transpeptidase level (p=0.0003) and higher prevalence of hepatic steatosis (p=0.0002). Advanced fibrosis [odds ratio (OR) 4.63, p=0.03] and IFNL3 major genotype (OR 0.13, p=0.001) were 2 independent factors for determining the presence of hepatic steatosis. Among the factors associated with sustained virological response, IFNL3 genotype was the most significant predictor, as per multivariate analysis.

CONCLUSIONS

Our results confirmed that IFNL3 genotype is associated with hepatic steatosis as well as IFN response.

Immunogenetic studies of the hepatitis C virus infection in an era of pan-genotype antiviral therapies - Effective treatment is coming

What are the factors that influence human hepatitis C virus (HCV) infection, hepatitis status establishment, and disease progression? Firstly, one has to consider the genetic background of the host and HCV genotypes. The immunogenetic host profile will reflect how each infected individual deals with infection. Secondly, there are environmental factors that drive susceptibility or resistance to certain viral strains. These will dictate (I) the susceptibility to infection; (II) whether or not an infected person will promote viral clearance; (III) the immune response and the response profile to therapy; and (IV) whether and how long it would take to the development of HCV-associated diseases, as well as their severity. Looking at this scenario, this review addresses clinical aspects of HCV infection, following by an update of molecular and cellular features of the immune response against the virus. The evasion mechanisms used by HCV are presented, considering the potential role of exosomes in infection. Genetic factors influencing HCV infection and pathogenesis are the main topics of the article. Shortly, HLAs, MBLs, TLRs, ILs, and IFNLs genes have relevant roles in the susceptibility to HCV infection. In addition, ILs, IFNLs, as well as TLRs genes are important modulators of HCV-associated diseases. The viral aspects that influence HCV infection are presented, followed by a discussion about evolutionary aspects of host and HCV interaction. HCV and HIV infections are close related. Thus, we also present a discussion about HIV/HCV co-infection, focusing on cellular and molecular aspects of this interaction. Pharmacogenetics and treatment of HCV infection are the last topics of this review. The understanding of how the host genetics interacts with viral and environmental factors is crucial for the development of new strategies to prevent HCV infection, even in an era of potential development of pan-genotypic antivirals.

Interferon-related genetic markers of necroinflammatory activity in chronic hepatitis C

INTRODUCTION

Chronic hepatitis C (CHC) is a major cause of liver disease worldwide which often leads to progressive liver inflammation, fibrosis, cirrhosis and hepatocellular carcinoma (HCC). CHC displays heterogeneous progression depending on a broad set of factors, some of them intrinsic to each individual such as the patient's genetic profile. This study aims to evaluate the contribution of certain genetic variants of crucial interferon alpha and lambda signaling pathways to the hepatic necroinflammatory activity (NIA) grade of CHC patients.

METHODS

NIA was evaluated in 119 CHC patients by METAVIR scale and classified as low (NIA = 0-2, n = 80) or high grade (NIA = 3, n = 39). In a candidate gene approach, 64 SNPs located in 30 different genes related to interferon pathways (IL-28B, IFNAR1-2, JAK-STAT and OAS1-3, among others) were genotyped using the Illumina GoldenGate® Genotyping Assay. Statistical association was determined by logistic regression and expressed as OR and 95% CI. Those SNPs significantly associated were further adjusted by other covariates.

RESULTS

Seven SNPs located in IL-28B (rs12979860), JAK1 (rs11576173 and rs1497056), TYK2 (rs280519), OAS1 (rs2057778), SOCS1 (rs33932899) and RNASEL (rs3738579) genes were significantly related to severe NIA grade (p<0.05). Regarding to clinical variables, elevated NIA was notably associated with aspartate aminotransferase (AST) serum levels >40 IU/L (p<0.05) but not with other clinical factors. Multivariate logistic regression analysis of these factors reflected that AST (>40 IU/L), TYK2 rs280519 (G allele) and RNASEL rs3738579 (G allele) were factors independently associated with elevated NIA (p<0.05). AST concentration showed a moderate AUC value (AUC = 0.63), similar to TYK2 (rs280519) and RNASEL (rs3738579) SNPs (AUC = 0.61, both) in the ROC_AUC analysis. Interestingly, the model including all significant variables reached a considerable predictive value (AUC = 0.74).

CONCLUSION

The identified genetic variants in interferon signaling pathways may constitute useful prognostic markers of CHC progression. Further validation in larger cohorts of patients is needed.

Interferon lambda polymorphisms associate with body iron indices and hepatic expression of interferon-responsive long non-coding RNA in chronic hepatitis C

Single nucleotide polymorphisms (SNPs) within DNA region containing interferon lambda 3 (IFNL3) and IFNL4 genes are prognostic factors of treatment response in chronic hepatitis C (CHC). Iron overload, frequently diagnosed in CHC, is associated with unfavorable disease course and a risk of carcinogenesis. Its etiology and relationship with the immune response in CHC are not fully explained. Our aim was to determine whether IFNL polymorphisms in CHC patients associate with body iron indices, and whether they are linked with hepatic expression of genes involved in iron homeostasis and IFN signaling. For 192 CHC patients, four SNPs within IFNL3-IFNL4 region (rs12979860, rs368234815, rs8099917, rs12980275) were genotyped. In 185 liver biopsies, histopathological analyses were performed. Expression of five mRNAs and three long non-coding RNAs (lncRNAs) was determined with qRT-PCR in 105 liver samples. Rs12979860 TT or rs8099917 GG genotypes as well as markers of serum and hepatocyte iron overload associated with higher activity of gamma-glutamyl transpeptidase and liver steatosis. The presence of two minor alleles in any of the tested SNPs predisposed to abnormally high serum iron concentration and correlated with higher hepatic expression of lncRNA NRIR. On the other hand, homozygosity in any major allele associated with higher viral load. Patients bearing rs12979860 CC genotype had lower hepatic expression of hepcidin (HAMP; P = 0.03). HAMP mRNA level positively correlated with serum iron indices and degree of hepatocyte iron deposits. IFNL polymorphisms influence regulatory pathways of cellular response to IFN and affect body iron balance in chronic hepatitis C virus infection.

The association of nonalcoholic fatty liver disease with genetic polymorphisms: a multicenter study

INTRODUCTION

Growing evidence suggests that multiple factors, such as insulin resistance, nutritional factors, gut microbiota, and hormones released from the adipose tissue, act together on genetically predisposed individuals. We aimed to investigate whether various single-nucleotide polymorphisms (SNPs) play a role in the development of nonalcoholic fatty liver disease (NAFLD) and severity of liver damage in the Anatolian population.

METHODS

Two hundred and sixteen patients with biopsy-proven NAFLD and 150 control participants, aged 18-70 years, were consecutively enrolled in this multicenter study. Blood samples were genotyped for the PNPLA3 (rs738409), IL28B (rs12979860, rs12980275, rs8099917), PPAR-α 227 ALA, PPAR-γ pro 12 ALA, SOD2 C47T, and LOX-1 IVS4-14 polymorphisms using the custom-made LightSNiP assays on a LightCycler 480 II instrument.

RESULTS

Genotypic distributions of PNPLA3 rs738409 SNPs were different between NAFLD and control participants, but not for other SNPs. The PNPLA3 rs738409 GG polymorphism was associated with a 27-fold increased risk of development of NAFLD (odds ratio=27.8, 95% confidence interval: 3.5-218.4; P=0.002). Patients with the PNPLA3 GG genotype had higher nonalcoholic fatty liver disease activity score levels compared with patients with the PNPLA3 CC genotype (P<0.005). NAFLD patients without fibrosis had a higher frequency of IL28B rs12979860 TT and rs12980275 GG genotypes compared with NAFLD patients with fibrosis (P<0.005).

CONCLUSION

The present study proposes that polymorphisms in the PNPLA3 gene have highly predictive value in the development of NAFLD and are independently associated with the severity of liver histology in patients with NAFLD. The results of this study suggest that IL28B rs12979860 TT or rs12980275 GG may play an important protective role against the development of advanced fibrosis and even cirrhosis.

Significance of genetic polymorphisms in patients with nonalcoholic fatty liver disease

Because of recent advances in genetic research such as genome-wide association studies, the underlying genetic mechanisms of nonalcoholic fatty liver disease (NAFLD) pathophysiology have been elucidated. Here, we present a review of the current literature on the impact of genetic polymorphisms in patients with NAFLD. These genetic polymorphisms, which regulate lipid metabolism, glucose metabolism, and the renin-angiotensin system, are involved in NAFLD onset, steatosis, inflammation, fibrosis, and hepatocellular carcinoma (HCC). Among these genetic polymorphisms, many studies and meta-analyses have demonstrated that position 148 (rs738409 C/G) of the patatin-like phospholipase domain-containing protein (PNPLA3) is a genetic factor associated with NAFLD pathophysiological features, such as hepatic fat level, hepatic inflammation, fibrosis, and HCC. However, the impact of genetic polymorphisms on NAFLD pathophysiology appears to differ among ethnic groups. Therefore, further studies with larger sample sizes are needed for each ethnic group.

Hepatic IFNL4 expression is associated with non-response to interferon-based therapy through the regulation of basal interferon-stimulated gene expression in chronic hepatitis C patients

Single nucleotide polymorphisms (SNPs) within or near interferon lambda 4 (IFNL4) gene located upstream of IFNL3 are associated with response to anti-HCV therapy both in interferon (IFN)-based and IFN-free regimens. IFNL4 encodes IFNλ4, a newly discovered type III IFN, and its expression is controlled by rs368234815-TT/ΔG, which is in strong linkage disequilibrium (LD) with other tag SNPs within or near IFNL4 such as rs12979860 and rs8099917. Intrahepatic expression levels of IFN-stimulated genes (ISGs) affect the responsiveness to IFNα and are also associated with IFNL4 genotype. However, IFNL4 expressions and its role in intrinsic antiviral innate immunity remain unclear. This study evaluated the effect of IFNL4 on intrahepatic ISG expression and investigated its relationship with treatment outcomes in liver samples obtained from 49 chronic hepatitis C patients treated with pegylated (PEG)-IFN/ribavirin therapy. IFNL4 mRNA was detected in 11 of 22 patients with IFNL4-unfavorable SNPs but not in patients with favorable genotypes. IFNL4 expression was associated with non-response to PEG-IFN/ribavirin therapy. Intrahepatic expression of antiviral ISGs (ISG15 and MX1) was significantly higher in IFNL4-unfavorable patients with detectable IFNL4 mRNA than in patients with undetectable IFNL4 mRNA, whereas the expression of suppressive ISGs (RNF125, SOCS1, SOCS3, and RNF11) was lower in patients with detectable IFNL4 mRNA. In summary, intrahepatic expression of IFNL4 was associated with increased antiviral ISG expression and decreased suppressive ISG expression at baseline, resulting in poor responsiveness to IFNα-based therapy in HCV infection.

The macrophage activation marker CD163 is associated with IL28B genotype and hepatic inflammation in chronic hepatitis C virus infected patients

Recent data highlighted the association of the macrophage activation marker CD163 with histological inflammation and fibrosis in chronic hepatitis C virus (HCV) infection. The aim of this study was to investigate the influence of successful antiviral treatment and IL28B genotypes on macrophage activation reflected by CD163 levels in HCV infected patients. In a retrospective cohort study, serum sCD163 levels were correlated with results of liver histopathology, IL28B genotyping and clinical parameters in 329 patients with HCV infection, 15 healthy controls and in 161 patients who achieved a sustained virologic response after antiviral treatment. sCD163 levels were significantly higher in patients with chronic HCV infection in comparison to healthy controls (5202 vs 896 ng/mL, P < 0.001). In the multivariate logistic regression analyses, sCD163 was independently associated with histologically determined inflammation (P = 0.043) but not with fibrosis (P = 0.091). sCD163 dropped significantly after successful antiviral treatment in comparison to baseline values (5202 vs 3093 ng/mL, P < 0.001). In the univariate analyses, sCD163 was significantly associated with IL28B genotype (C/C vs C/T+T/T) with higher values in the C/C group (6098 vs 4812 ng/mL, P = 0.003). In the multivariate logistic regression model, sCD163 levels were significantly associated with IL28B genotype (P = 0.003) and sustained virologic response (SVR) (P < 0.001). Our data support the association of activated liver macrophages with hepatic necroinflammation in chronic HCV infection as sCD163 levels drop rapidly after SVR. The irresponsiveness of IL28B minor genotypes to interferon might be related to a lower level of macrophage activation in these patients.

TM6SF2 rs58542926 is not associated with steatosis and fibrosis in large cohort of patients with genotype 1 chronic hepatitis C

BACKGROUND & AIMS

We tested the putative association of the rs58542926 variant of TM6SF2, a recently described genetic determinant of nonalcoholic fatty liver disease, with steatosis and fibrosis in genotype 1(G1) chronic hepatitis C(CHC) patients.

METHODS

A total of 694 consecutively biopsied Caucasian G1 CHC patients were genotyped for TM6SF2 rs58542926, IL28B rs12979860 and PNPLA3 rs738409. Steatosis was classified as absent (<5%), mild-moderate(5-29%) and severe(≥30%), Fibrosis was considered severe if=F3-F4.

RESULTS

Carriers of TM6SF2 rs58542926 (6.3% of patients) exhibited lower serum levels of cholesterol (P = 0.04) and triglycerides (P = 0.01), but a similar distribution of steatosis severity (P = 0.63), compared to noncarriers. Prevalence and severity of steatosis were reduced in IL28B C allele carriers (P = 0.005) and elevated in PNPLA3 G allele carriers (P < 0.001). After adjustment for age, gender, body mass index and homoeostasis model assessment score, steatosis severity was independently associated with IL28B rs12979860 (odds ratio [OR] 0.69, 95% confidence interval [CI] 0.55-0.86, P = 0.001) and PNPLA3 rs738409 (OR 1.84, 95% CI 1.46-2.83, P < 0.001), but not TM6SF2 rs58542926 (OR 1.48, 95% CI 0.82-2.69, P = 0.19). Variants of TM6SF2 (30.9% vs. 25%, P = 0.40), IL28B and PNPLA3 were not directly associated with fibrosis severity, although variants of IL28B and PNPLA3 promoted steatosis (OR 1.36, 95% CI 1.06-1.75, P = 0.01) that in turn is associated with severe fibrosis.

CONCLUSIONS

In G1 CHC patients, TM6SF2 rs58542926 does not affect the histological severity of liver damage. However, IL28B rs12979860 and PNPLA3 rs738409 modify steatosis.

DEPDC5 variants increase fibrosis progression in Europeans with chronic hepatitis C virus infection

Chronic hepatitis C virus (HCV) infection may progress to cirrhosis and hepatocellular carcinoma (HCC). Recently, two genetic variants, DEPDC5 rs1012068 and MICA rs2596542, were associated with the onset of HCC in Asian subjects with chronic HCV infection. The aim of the present study was to analyze whether DEPDC5 and MICA genetic variants were associated with liver disease progression in European subjects with chronic HCV infection. In a Northern Italian discovery cohort (n = 477), neither DEPDC5 rs1012068 nor MICA rs2596542 were associated with HCC (n = 150). However, DEPDC5 rs1012068 was independently associated with cirrhosis (n = 300; P = 0.049). The association of rs1012068 with moderate to severe fibrosis was confirmed in an independent cross-sectional German cohort (n = 415; P = 0.006). Furthermore, DEPDC5 rs1012068 predicted faster fibrosis progression in a prospective cohort (n = 247; P = 0.027). Next, we examined the distribution of nonsynonymous DEPDC5 variants in the overall cross-sectional cohort (n = 912). The presence of at least one variant increased the risk of moderate/severe fibrosis by 54% (P = 0.040). To understand the molecular mechanism underlying the genetic association of DEPDC5 variants with fibrosis progression, we performed in vitro studies on immortalized hepatic stellate cells (LX-2). In these cells, down-regulation of DEPDC5 resulted in increased expression of β-catenin and production of its target matrix metallopeptidase 2 (MMP2), a secreted enzyme involved in fibrosis progression.

CONCLUSION

DEPDC5 variants increase fibrosis progression in European subjects with chronic HCV infection. Our findings suggest that DEPDC5 down-regulation may contribute to HCV-related fibrosis by increasing MMP2 synthesis through the β-catenin pathway.

Relationship between IL28B gene rs8099917 polymorphism and SVR in Turkish patients with hepatitis C virus genotype 1

BACKGROUND AND OBJECTIVE

The hepatitis C virus (HCV) which infects 3% of the world's population is a global challenge. Recently, genome-wide association studies (GWAS) have identified that the IL28B gene rs8099917 polymorphism was associated with the response to the pegylated-interferon alpha/ribavirin (PegIFNα/RBV) combination therapy in patients infected with HCV genotype 1. IL28B gene rs8099917 polymorphism should be determined before beginning treatment of HCV-infected patients to predict an individual's response. The aims of this study were to analyze the correlation between IL28B gene rs8099917 (T/G) polymorphism and PegIFNα/RBV therapy outcome in the Turkish population.

METHODS

Genotypes of the IL28B gene rs8099917 (T/G) single nucleotide polymorphism (SNP) were determined in 308 patients with HCV infection by using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. One group consisted of 148 patients with a sustained virological response (SVR), whereas the second group consisted of 160 nonresponders (non-SVR).

RESULTS

Allele and genotype associations of IL28B gene rs8099917 polymorphism with a sustained virological response were observed in comparisons between the SVR and non-SVR groups (P<0.001). In addition, the characteristics of the subjects did not differ between these two groups except for age and fibrosis stage (P<0.05). Additionally, neither SVR nor rs80999917 genotypes were associated by HCV RNA levels.

CONCLUSIONS

In conclusion, the rs8099917 polymorphism was thus found strongly associated with a sustained virological response to therapy in Turkish patients infected with HCV genotype 1. Consequently, we suggest determining IL28B gene rs8099917 polymorphism of patients with HCV genotype 1 before onset of treatment.

Impact of OAS1 Exon 7 rs10774671 Genetic Variation on Liver Fibrosis Progression in Egyptian HCV Genotype 4 Patients

The aim of this study was to assess the impact of genetic variants of oligoadenylate synthetase 1 (OAS1) single-nucleotide polymorphism (SNP) rs10774671 at the exon 7 splice acceptor site on liver fibrosis progression and hepatitis C virus (HCV) outcome in Egyptian HCV genotype 4 patients. In this study, 195 subjects were enrolled; 60 controls and 135 chronic HCV genotype 4 patients with different fibrosis grades. All subjects were genotyped for OAS1 SNP rs10774671 polymorphism by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. There was an increasing trend of liver fibrosis progression as 52.9% GG, 73.6% GA, and 83.3% AA genotypes were detected in late fibrosis patients (p = 0.025). The AA genotype was higher in the late fibrosis group than in the early fibrosis group (83.3% vs. 16.7%) (p = 0.001). The A allele was significantly affecting the liver fibrosis progression rate, more than the G allele (p = 0.001). The multivariate analysis showed that the OAS1 GA and AA genotypes were independent factors associated with liver progression (p = 0.009, odds ratio [OR] 3.467, 95% confidence interval [CI] 1.273-7.584). In addition, the A allele was associated with liver fibrosis progression (p = 0.014, OR 2.525, 95% CI 1.157-4.545). The polymorphism at OAS1 exon 7 rs3741981 might be a potential genetic marker and can be useful in the assessment of liver fibrosis progression and disease outcome in HCV-infected patients.

Duplex High-Resolution Melting Assay for the Simultaneous Genotyping of IL28B rs12979860 and PNPLA3 rs738409 Polymorphisms in Chronic Hepatitis C Patients

Chronic hepatitis C (CHC) is a major burden for public health worldwide. Although newer direct-acting antivirals show good efficacy, their cost precludes their wide adoption in resource-limited regions. Thus, strategies are being developed to help identify patients with high susceptibility to response to classic PEG-interferon + ribavirin therapy. IL28B polymorphism rs12979860 C/T is an important predictor for an efficient response to interferon-based therapy. A genetic variant in adiponutrin (PNPLA3) gene, rs738409 C/G, is associated with steatosis, severity, and progression of liver fibrosis in CHC patients, and predicts treatment outcome in difficult-to-cure HCV-infected patients with advanced fibrosis. We developed a rapid and inexpensive assay based on duplex high-resolution melting (HRM) for the simultaneous genotyping of these two polymorphisms. The assay validation was performed on synthetic DNA templates and 132 clinical samples from CHC patients. When compared with allele-specific PCR and sequencing, our assay showed 100% (95% CI: 0.9724-1) accuracy, with 100% sensitivity and specificity. Our assay was robust against concentration and quality of DNA samples, melting curve normalization intervals, HRM analysis algorithm, and sequence variations near the targeted SNPs (single nucleotide polymorphism). This duplex assay should provide useful information for patient-oriented management and clinical decision-making in CHC.

Genetic Variants in Interleukin-28B Are Associated with Diabetes and Diabetes-Related Complications in Patients with Chronic Hepatitis C Virus Infection

BACKGROUND

Few studies have shown that host interleukin-28B (IL28B) genetic polymorphisms are associated with insulin resistance in patients with chronic hepatitis C virus (HCV) infection. However, the clinical relevance of this relationship is unclear.

AIMS

We examined the association between IL28B genotype for rs12980275 and risk of type 2 diabetes and diabetes-related complications.

METHODS

We used a cross-sectional study of prospectively recruited male veterans with chronic HCV. We employed logistic regression analysis and adjusted for patients' age, race, body mass index, and hepatic fibrosis.

RESULTS

A total of 528 participants were recruited (mean age 59.1 years; 38.5 % African-American; 40.3 % advanced fibrosis). Of these, 36.1 % were homozygous for favorable AA allele for rs12980275, 49.0 % were heterozygous (AG), and 14.0 % were homozygous for the unfavorable allele (GG). Prevalence of diabetes was significantly lower in patients with both favorable alleles (AA) than that with at least one unfavorable IL28B G allele (21.1 vs. 30.2 %, p = 0.02). Similarly, patients who were homozygous for the favorable alleles had lower prevalence of diabetes-related complications than patients with any unfavorable IL28B allele (5.7 vs. 12.2 %, p = 0.01). This association did not change after adjusting for sociodemographic characteristics, body mass index, and stage of hepatic fibrosis (adjusted ORdiabetes 0.56, 95 % CI 0.35-0.89; ORdiabetes-related complications 0.47, 95 % CI 0.23-0.96).

CONCLUSIONS

Patients who have favorable AA IL28B alleles have a lower prevalence of diabetes and related complications compared with patients with unfavorable IL28B rs12980275 genotype. IL28B genotype information may be used to counsel HCV patients regarding their individualized risk of diabetes and diabetes-related complications.

Impact of rs12979860 polymorphism on liver morphology in chronic HCV infection

AIM OF THE STUDY

To determine distribution of rs12979860 genotypes, their correlations with viral load as well as inflammatory activity and stage of liver fibrosis in patients infected with HCV genotype 1.

MATERIAL AND METHODS

The study included 132 patients infected with HCV genotype 1b. Serum viral loads were obtained with the PCR method. Rs12979860 polymorphisms were determined by sequencing of PCR products. Liver biopsy was performed in all patients.

RESULTS

CT, TT and CC alleles of rs12979860 polymorphism were detected in 58%, 20% and 22% of patients respectively. The highest viral load was observed in the TT and the lowest in the CC group (72.0 × 10⁶ IU/ml vs. 2.1 × 10⁶ IU/ml, p < 0.005). A significant correlation was demonstrated between patient's age and inflammatory activity as well as degree of liver fibrosis. No association was found between liver histopathology and HCV viral load or rs12979860 genotypes.

CONCLUSIONS

There is an association between HCV viral load and rs12979860 polymorphism. Inflammatory activity and stage of liver fibrosis depend on age, but there is no relationship with rs12979860 genotypes and HCV viral load.

Innate and adaptive genetic pathways in HCV infection

Infection with hepatitis C virus (HCV) leads to a wide spectrum of clinical manifestations. This heterogeneity is underpinned by the host immune response and the genetic factors that govern it. Polymorphisms affecting both the innate and adaptive immunity determine the outcome of exposure. However the innate immune system appears to play a greater role in determining treatment-associated responses. Overall the effects of IFNL3/4 appear dominant over other polymorphic genes. Understanding how host genetics determines the disease phenotype has not been as intensively studied. This review summarizes our current understanding of innate and adaptive immunogenetic factors in the outcome of HCV infection. It focuses on how they relate to resolution and the progression of HCV-related liver disease, in the context of current and future treatment regimes.

Interferon-λ rs12979860 genotype and liver fibrosis in viral and non-viral chronic liver disease

Tissue fibrosis is a core pathologic process that contributes to mortality in ~45% of the population and is likely to be influenced by the host genetic architecture. Here we demonstrate, using liver disease as a model, that a single-nucleotide polymorphism (rs12979860) in the intronic region of interferon-λ4 (IFNL4) is a strong predictor of fibrosis in an aetiology-independent manner. In a cohort of 4,172 patients, including 3,129 with chronic hepatitis C (CHC), 555 with chronic hepatitis B (CHB) and 488 with non-alcoholic fatty liver disease (NAFLD), those with rs12979860CC have greater hepatic inflammation and fibrosis. In CHC, those with rs12979860CC also have greater stage-constant and stage-specific fibrosis progression rates (P<0.0001 for all). The impact of rs12979860 genotypes on fibrosis is maximal in young females, especially those with HCV genotype 3. These findings establish rs12979860 genotype as a strong aetiology-independent predictor of tissue inflammation and fibrosis.

Tissue fibrosis is a major contributor to mortality in the developed world. Here, the authors identify a genetic variant in the intronic region of interferon-λ4 that is a strong predictor of hepatic inflammation and fibrosis, independent of liver disease aetiology