Polymorphisms in the interleukin-10, tumor necrosis factor-alpha, and transforming growth factor-beta1 genes in chronic hepatitis C patients treated with interferon and ribavirin

Cytokine (IL-10, IL-6, TNF-α and TGF-β1) Gene Polymorphisms in Chronic Hepatitis C Virus Infection among Malay Male Drug Abusers

Cytokines play an important role in modulating inflammation during viral infection, including hepatitis C virus (HCV) infection. Genetic polymorphisms of cytokines can alter the immune response against this infection. The objective of this study was to investigate the possible association between chronic hepatitis C virus infection susceptibility and cytokine gene polymorphism for interleukin-10 (IL-10) rs1800896 and rs1800871, interleukin 6 (IL-6) rs1800795, TNF-α rs1800629, and TGF-β1 rs1800471 in Malay male drug abusers. The study was conducted on 76 HCV-positive (HP) male drug abusers and 40 controls (HCV-negative male drug abusers). We found that there were significant differences in the frequencies of genotype for IL-10 rs1800871 (p = 0.0386) and at the allelic level for IL-10 rs1800896 A versus G allele (p = 0.0142) between the HP group and the control group. However, there were no significant differences in gene polymorphism in interleukin 6 rs1800795, TNF-α rs1800629 and TGF-β1 rs1800471. These findings suggest significant associations between gene polymorphism for IL-10 rs1800871, IL-10 rs1800896 (at the allelic level) and susceptibility to HCV infection among Malay male drug abusers.

IL-10 Polymorphisms and Haplotypes Predict Susceptibility to Hepatocellular Carcinoma Occurrence in Patients with Hepatitis C Virus Infection from Northeast India

Chronic hepatitis C virus (HCV) infection leads to variable outcomes, ranging from prolonged slow hepatic damage leading to cirrhosis, and hepatocellular carcinoma (HCC). Polymorphism in cytokines IL-10 and IL-12 that impact the immune response to HCV infection may play a role in determining this outcome. This study was aimed to determine if polymorphisms in IL-10 and IL-12B contribute to HCV susceptibility and the risk of developing HCC in patients from Northeast India. IL-10 - 1082, -819, -592 polymorphisms and IL-12B -1188 polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism in a total of 266 HCV-infected patients and 100 age- and sex-matched controls. In the HCV-infected subjects, 110 patients had chronic hepatitis C (CHC), 96 with liver cirrhosis, and 60 with HCC. Serum levels of IL-10 were also measured and correlated with disease severity. Haplotype analysis for IL-10 polymorphisms was carried out. Statistical data were analyzed using SPSS ver. 22.0. The frequency of IL-10 - 592 AA genotype/A allele was significantly higher in HCC patients than in CHC patients. The intermediate IL-10-producing ACC haplotype was significantly more frequent in HCC and cirrhotic patients than in CHC patients. No significant association was found for IL-10 - 819, -592 and IL-12B -1188 polymorphisms with the susceptibility to HCV infection or occurrence of HCC in HCV-infected patients. IL-10 - 592 CA polymorphism and IL-10 ACC haplotype are significant biomarkers of HCC in HCV-infected patients from Northeast India. Higher serum levels of IL-10 were also linked to higher disease severity.

Association of TGF-ß1 polymorphisms and chronic hepatitis C infection: a Meta-analysis

Background

Although several researches have reported the connection between the transforming growth factor-beta 1 (TGF-β1) gene polymorphisms and chronic hepatitis C virus (HCV) infection, the conclusions of these studies were not always consistent. Here, this paper proposed a meta-analysis to evaluate whether the TGF-ß1 gene polymorphisms, −509C/T (rs1800469), codon 10 T/C (rs1982073) and codon 25G/C (rs1800471), were associated with chronic HCV infection.

Methods

The summary odds ratios (ORs) of chronic HCV infected patients and controls with all SNPs were obtained by adaptive fixed or random effect model. A series of statistical tools were employed to guarantee the accuracy of related pooling ORs, including the Hardy-Weinberg equilibrium (HWE) test, sensitivity analysis and publication bias test.

Results

This paper analyzed 18 case-control studies in 17 articles which totally contains 2718 chronic HCV infection cases corresponding to 1964 controls. The results of the meta-analysis indicated that the −509C/T polymorphism effected an increased risk of chronic HCV infection in all gene models. More specifically by ethnicity stratification, the Egyptians shared the similar association with the above overall study. Moreover, the meta-fusion of healthy control studies showed that − 509 T allele carriers (TT + TA) had nearly 2.00 and 3.36 fold higher risk of chronic HCV infection in the total and Egyptian populations, respectively (OR = 2.004, 95% CI = 1.138–3.528, P = 0.016; OR = 3.363, 95% CI = 1.477–7.655, P = 0.004, respectively). However, our meta-analysis did not find any significant association between the codon 10 T/C or codon 25G/C polymorphisms and chronic HCV infection.

Conclusions

Our results suggested that the TGF-ß1–509C/T polymorphism may effect an increased risk of chronic HCV infection, especially in Egyptian population.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4390-8) contains supplementary material, which is available to authorized users.

Variation in the Untranslated Genome and Susceptibility to Infections

The clinical outcomes of infections are highly variable among individuals and are determined by complex host-pathogen interactions. Genome-wide association studies (GWAS) are powerful tools to unravel common genetic variations that are associated with disease risk and clinical outcomes. However, GWAS has only rarely revealed information on the exact genetic elements and their effects underlying an association because the majority of the hits are within non-coding regions. Some of the variants or the linked polymorphisms are now being discovered to have functional significance, such as regulatory elements in the promoter and enhancer regions or the microRNA binding sites in the 3′untranslated region of the protein-coding genes, which influence transcription, RNA stability, and translation of the protein-coding genes. However, only 3% of the entire transcriptome is protein-coding, signifying that non-coding RNAs represent most of the transcripts. Thus, a large portion of previously identified intergenic GWAS single nucleotide polymorphisms (SNPs) is in the non-coding RNAs. The non-coding RNAs form a large-scale regulatory network across the transcriptome, greatly expanding the complexity of gene regulation. Accumulating evidence also suggests that the “non-coding” genome regions actively regulate the highly dynamic three dimensional (3D) chromatin structures, which are critical for genome function. Epigenetic modulation like DNA methylation and histone modifications further affect chromatin accessibility and gene expression adding another layer of complexity to the functional interpretation of genetic variation associated with disease outcomes. We provide an overview of the current information on the influence of variation in these “untranslated” regions of the human genome on infectious diseases. The focus of this review is infectious disease-associated polymorphisms and gene regulatory mechanisms of pathophysiological relevance.

Viral and host factors associated with outcomes of hepatitis C virus infection (Review)

Hepatitis C virus (HCV) infection is a major health issue globally. Owing to the progress made in host genetics and HCV molecular virology, emerging data have suggested that the natural course and treatment response in patients with HCV infection are largely determined by complex host‑viral interactions. HCV genotype is the most important viral factor predicting the response to pegylated interferon‑α plus ribavirin therapy. The subtype of HCV genotype 1 is the key viral factor that predicts the efficacy of direct‑acting antiviral therapy. HCV genome heterogeneity and baseline viral load are additionally associated with the treatment response. Multiple host genetic variants localized in genes associated with the immune response have been identified as predictors of spontaneous disease course and therapy outcome in chronic HCV. However, most findings from candidate gene association studies have not been proven universal for all investigated populations and independent studies. Previous findings in independent large genome wide association studies confirmed that interferon‑λ3 gene polymorphisms are associated with spontaneous clearance and treatment responsiveness. A polymorphism of the inosine triphosphatase gene has been identified as a protective factor against ribavirin‑induced anemia and dose reductions. Another genetic variant in the patatin‑like phospholipase domain containing 3 genes is associated with hepatic steatosis and fibrosis in patients with HCV. The present review focused on the identified viral and host factors associated with outcomes of patients with HCV, and assessed the involvement of viral and host genetics in the natural history and treatment outcomes of HCV infection. This will provide novel ideas concerning personalized prevention and individualized clinical management.

IL-10 and IL-28B gene variants as predictors of sustained response to peginterferon and ribavirin therapy in chronic HCV infection

OBJECTIVES

Interleukin-10 (IL-10) plays an important role in the immunity to hepatitis C virus (HCV). Insofar as IL-10 variants are associated with altered levels of IL-10, previous studies that examined the association of IL-10 polymorphisms with the susceptibility to and progression of chronic HCV, and response to anti-viral treatment were inconsistent. We investigated the association between common IL-10 variants in the intron and the promotor region with HCV and associated features.

METHODS

Study subjects comprised 120 patients infected with HCV-1b, and treated with Peg-IFN/RBV. Genotyping of six IL-10 promoter variants in the intron region (rs1878672, rs1554286, rs1518111) and promotor region (rs1800872, rs1800871, rs1800896) were done by real-time PCR.

RESULTS

Compared to G/G, carriage of IL-10 rs1800896 (-1082A/G) A/A genotype was more frequent in patients with sustained virological response (SVR). The decline in viral load over the first 12weeks of treatment was more pronounced in rs1800896 A/A genotype carriers, compared to G/G genotype carriers, and was irrespective of the treatment dosage. Carriage of rs1800896 A/A genotype was positively associated with improvement in viral load decline, which was simultaneous, with and without carriage of the common favourable IL-28B variant. Carriage of both IL-10 rs1800896 G/G and IL-28B non-favourable genotype was associated with twice the risk of getting slow decline of viral load during treatment. Haploview analysis identified ACGCTA and CCGCTG haplotypes to be linked with excellent PegIFN/RBV cure rate, and complete HCV eradication. On the other hand, ACGCTG and CCGCTA haplotypes were associated with resistance to PegIFN/RBV treatment.

CONCLUSION

IL-10 rs1800896 variant markedly influences the clinical outcome of HCV infection, and is a determinant of the response to HCV treatment.

The Synergistic Effect of TNFα -308 G/A and TGFβ1 -509 C/T Polymorphisms on Hepatic Fibrosis Progression in Hepatitis C Virus Genotype 4 Patients

Tumor necrosis factor-alpha (TNFα) and transforming growth factor-beta (TGFβ1) cytokines are highly implicated in liver fibrosis. Polymorphisms in these cytokines affect their expression, secretion, and activity. This study aimed to evaluate the influence of TNFα -308 G/A and TGFβ1 -509 C/T polymorphism on hepatic fibrosis progression in Egyptian patients with hepatitis C virus (HCV) genotype 4. Genotyping of TNFα -308 G/A and TGFβ1 -509 C/T was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis in 122 subjects (50 healthy controls and 72 HCV patients). Also, serum TNFα and TGFβ1 levels were detected by enzyme-linked immunosorbent assay (ELISA). The genotyping results of early (F0-F1, n = 36) and late (F2-F4, n = 36) HCV fibrosis patients showed that late fibrosis patients had higher TNFα -308 AA genotype and TGFβ1 -509 TT genotype than early fibrosis patients (p = 0.016, 0.028, respectively). Moreover, the TNFα and TGFβ1 serum levels were significantly higher in HCV patients with TNFα A containing genotypes (GA+AA) (p = 0.004) and patients with TGFβ1 T containing genotypes (CT+TT) (p = 0.001), respectively. The combined unfavorable TNFα (GA/AA) and TGFβ1 (CT/TT) genotypes were highly associated with abnormal liver function parameters and were significantly higher in high activity (A2-A3) and late fibrosis (F2-F4) HCV patients (p = 0.023, 0.029). The multivariate analysis results confirmed that the combined TNFα-308 (AA) and TGFβ1 -509 (TT) unfavorable genotypes increased the risk of hepatic fibrosis progression by 6.4-fold than combined favorable genotypes (odds ratio: 6.417, 95% confidence interval [1.490-27.641], p = 0.013). In conclusion, both TNFα -308 G/A and TGFβ1 -509 C/T polymorphisms synergistically influence the hepatic fibrosis progression and can be used as potential biomarkers to predict hepatic disease progression in chronic hepatitis C patients.

Effect of interleukin-10 gene promoter polymorphisms -1082 G/A and -592 C/A on response to therapy in children and adolescents with chronic hepatitis C virus infection

BACKGROUND AND AIM

Studying predictors of response to therapy for hepatitis C virus (HCV) infection in children may help avoid the inappropriate use of currently available costly therapy associated with numerous adverse effects. We tested the hypothesis that inheritance of single nucleotide polymorphisms (SNPs) of the interleukin-10 (IL-10) promoter gene might influence response to HCV treatment.

PATIENTS AND METHODS

The impact of SNPs, -1082 G/A and -592 C/A, in the promoter region of IL-10 gene, on response to HCV therapy was assessed in a cohort of 40 children treated with a combination of pegylated interferon (Peg-IFN) α2b and ribavirin.

RESULTS

Sustained virological response was achieved in 48.7%. High viral load was associated with non-response to therapy. There was no association between histopathological degree of inflammation or fibrosis and response to therapy. There was no direct statistically significant association between polymorphisms in the IL-10 gene (-1082G/A and -592 C/A) as regards inflammation or response to therapy in children. As for the SNP -592 C/A; there was a statistically significant association with the score of fibrosis (P<0.004), concluding that the A allele was protective from moderate and severe fibrosis. Meanwhile the SNP -1082G/A did not show any association with the fibrosis score.

CONCLUSION

We could not associate response to therapy for HCV with IL-10 polymorphisms -1082 G/A and -592 C/A. For the SNP -592 C/A, the A allele protected from moderate and severe fibrosis.

Role of Some Predominant Host Immunomodulators' Single Nucleotide Polymorphisms in Severity of Hepatitis B Virus and Hepatitis C Virus Infection

Hepatitis B and C infections can be either acute or chronic. The chronic infection can culminate in liver cirrhosis and hepatocellular carcinoma. Influence of the host genetic makeup on conversion of acute to chronic infection, development of cirrhosis, and hepatocellular carcinoma is an interesting area of research. Variability in different immune system genes may account for such differences in the outcome of infection. This article discusses single nucleotide polymorphisms in different host immunomodulator genes that have been frequently reported to influence the outcome of infection and severity of disease. The genetic variability could be utilized for the prediction of disease outcome and treatment responses.

Interleukin 10 gene single nucleotide polymorphisms in Polish patients with chronic hepatitis C: Analysis of association with severity of disease and treatment outcome

It is suggested that interleukin 10 (IL-10), as a modulator of immune response, is likely to influence the elimination of hepatitis C virus (HCV), the progression of chronic hepatitis C (CHC) and the response to interferon-based therapy in CHC patients. The aim of the study was to analyze the association of single nucleotide polymorphisms (SNPs) of IL-10 gene with severity of liver disease (degree of inflammation and stage of fibrosis) and outcome of pegylated interferon alpha and ribavirin combined therapy (sustained virological response (SVR) and relapse) in 196 Polish CHC patients infected with HCV genotype 1. The analysis included IL-10 promoter SNPs: -1082(A/G) rs1800896, -819(C/T) rs1800871, -592(C/A) rs1800872 and SNP in the 3' UTR of IL-10 gene: +4529(A/G) rs3024498. Genotyping was performed using PCR-RFLP and HRM analysis. It was demonstrated that the -592C allele is associated with mild hepatic inflammation. Moreover, it was found that the -819C allele might be associated with SVR and that the ACCA haplotype and intermediate IL-10 producer ACC haplotype are associated with SVR and non-relapse. It can be concluded that IL-10 SNPs are associated with severity of disease and response to therapy and may be considered as potential prognostic and predictive markers in CHC.

Interleukin-10.rs1800896 and Interleukin-18.rs1946518 gene polymorphisms could not predict the outcome of hepatitis C virus infection in Egyptian patients treated with pegylated interferon plus ribavirin

A single-nucleotide polymorphism (SNP) in the interleukin (IL)-28B gene was used as a major predictor of the response to treatment in patients with hepatitis C virus (HCV) infection. Data examining the role of IL-10 and IL-18 gene polymorphisms among HCV genotype 4 (G4)-infected Egyptians in response to pegylated interferon (PEG-IFN) plus ribavirin (RBV) therapy are limited. This study investigated the impact of SNP at IL-10.rs1800896 (at position -1082) and IL-18.rs1946518 genes (at position -607) on the response to PEG-IFN/RBV therapy in HCV-infected Egyptians. This study was carried out on 100 HCV patients treated with PEG-IFN plus RBV and 100 healthy controls. The HCV patients included 50 treatment non-responders (NR) and 50 subjects with sustained virologic response (SVR). Genomic DNA from venous blood of subjects was extracted and IL-10.rs1800896 and IL-18.rs1946518 genotypes were determined using allele-specific amplification and SYBR Green real-time PCR. Linkage disequilibrium between the two SNPs was estimated using Haploview software. The frequency of the IL-10.rs1800896 AA, AG and GG genotypes among non-responders were 16 %, 70 % and 14 % while among SVR subjects, the frequency was 34 %, 60 % and 6 %, respectively (p=0.073). On the other hand, the frequency of the IL-18.rs1946518 AA, AC and CC genotypes among non-responders was 14 %, 50 % and 36 %, respectively, while among responders, these frequencies were 28 %, 44 % and 28 %, (p = 0.220). Both markers were in linkage equilibrium (D' = 0.23; r (2) = 0.052). SNPs in the IL-10.rs1800896 and IL-18.rs1946518 genes could not predict the outcome of HCV infection in Egyptians treated with PEG-IFN/RBV.

Tumour necrosis factor -308 and -238 promoter polymorphisms are predictors of a null virological response in the treatment of Brazilian hepatitis C patients

Certain host single nucleotide polymorphisms (SNPs) affect the likelihood of a sustained virological response (SVR) to treatment in subjects infected with hepatitis C virus (HCV). SNPs in the promoters of interleukin (IL)-10 (-1082 A/G, rs1800896), myxovirus resistance protein 1 (-123 C/A, rs17000900 and -88 G/T, rs2071430) and tumour necrosis factor (TNF) (-308 G/A, rs1800629 and -238 G/A, rs361525) genes and the outcome of PEGylated α-interferon plus ribavirin therapy were investigated. This analysis was performed in 114 Brazilian, HCV genotype 1-infected patients who had a SVR and in 85 non-responders and 64 relapsers. A significantly increased risk of having a null virological response was observed in patients carrying at least one A allele at positions -308 [odds ratios (OR) = 2.58, 95% confidence intervals (CI) = 1.44-4.63, p = 0.001] or -238 (OR = 7.33, 95% CI = 3.59-14.93, p < 0.001) in the TNF promoter. The risk of relapsing was also elevated (-308: OR = 2.87, 95% CI = 1.51-5.44, p = 0.001; -238: OR = 4.20, 95% CI = 1.93-9.10, p < 0.001). Multiple logistic regression of TNF diplotypes showed that patients with at least two copies of the A allele had an even higher risk of having a null virological response (OR = 16.43, 95% CI = 5.70-47.34, p < 0.001) or relapsing (OR = 6.71, 95% CI = 2.18-20.66, p = 0.001). No statistically significant association was found between the other SNPs under study and anti-HCV therapy response.

Association of cytokine gene polymorphisms with hepatitis C virus infection in a population from Rio de Janeiro, Brazil

Background

The host immune response is an important indicator of the outcome of hepatitis C virus (HCV) infection and disease progression. The aim of this study was to explore cytokine gene polymorphisms as a candidate for susceptibility to persistent HCV infection or HCV spontaneous clearance in a population from Rio de Janeiro, Brazil.

Methods

Genetic polymorphisms in the cytokines, tumor necrosis factor-alpha (−308), transforming growth factor-beta 1 (codons 10 and 25), interleukin-10 (IL-10; −1082 and −592), IL-6 (−174), and interferon-gamma (+874) were analyzed by polymerase chain reaction sequence-specific primers in 245 patients with chronic hepatitis C (CHC), 41 spontaneous recovery (SR) patients, and 189 healthy volunteers. Further, polymorphisms in IL-28B (rs12979860, rs12980275, and rs8099917) were assessed by real-time polymerase chain reaction in all groups.

Results

The IL-28B rs12979860 CC and rs12980275 AA genotypes were significantly associated with SR of HCV infection and response to therapy, whereas the C allele of IL-6 (−174) was associated with protection to CHC. A multivariate analysis showed that the male sex and IL-28B rs12979860 CT and TT and transforming growth factor-beta 1 (codon 10) TC genotypes were factors associated with CHC. Additionally, IL-6 (−174) C allele was increased in SR patients compared with patients with CHC.

Conclusion

IL-28B polymorphisms are associated with spontaneous clearance of HCV and response to therapy in a Brazilian population. Also, IL-6 (−174) C allele is involved in SR and decreased inflammation scores.

Polymorphisms of IL-10 gene in patients infected with HCV under antiviral treatment in southern Brazil

Interleukin-10 (IL-10) is a cytokine that plays an important role in the regulation of the immune system. Gene polymorphisms of IL-10 have been associated with the different expression levels of this cytokine. In hepatitis C virus infection, IL-10 appears to interfere with the progression of disease, viral persistence and the response to therapy. This study investigated genetic variability in the IL-10 gene promoter between patients infected with hepatitis C virus (HCV) and healthy individuals, associating the frequency of polymorphisms with different aspects of viral infection. This is a case-control study with 260 patients who were infected with HCV and 260 healthy individuals. Genotyping of the polymorphisms was performed using the technique of amplification refractory mutation system PCR (ARMS-PCR) for regions of the IL-10 gene promoter (-1082 G/A, -819 C/T, -592 C/A). The frequencies of alleles and genotypes related to polymorphisms in the IL-10 gene promoter showed a higher frequency of the G allele and genotype GG in the -1082 region between the infected group and the control group (p=0.005 and p=0.001, respectively), whereas the AA genotype was significantly more frequent in the control group. The frequencies of the haplotypes GTA and GCC were higher in the group of infected individuals, whereas the haplotype ATA was more frequent in the healthy group (p<0.006). It was also observed that the genotypes GG and AG in the region -1082 were significantly more frequent among patients infected with HCV who were in advanced stages of fibrosis and cirrhosis (p=0.042). No association was observed between polymorphisms of IL-10 and sustained virologic response (SVR).

IL-10 promoter polymorphisms influence susceptibility to aGvHD and are associated with proportions of CD4+FoxP3+ lymphocytes in blood after hematopoietic stem cell transplantation

Four hundred and ninety-five patients (390 and 105 grafted from unrelated and sibling (SIB) donors, respectively) and their donors were analyzed for the impact of interleukin-10 (IL-10) promoter genotype [rs18000896 (-1082 G/A), rs18000871 (-819 C/T) and rs18000872 (-592 C/A)] on the outcome of hematopoietic stem cell transplantation (HSCT). Patients having ACC haplotype were at a lower risk of acute graft versus host disease (aGvHD, grade > I) if transplanted from human leukocyte antigen (HLA) well-matched (10/10) unrelated donors (20/135 vs 39/117, P < 0.001, Pcorr = 0.002), which was not seen if patients were transplanted from either sibling (SIB) or poorly matched (<10/10) unrelated donors (MUD). In addition, GCC haplotype positive recipients of unrelated donor transplants tended to be more susceptible to aGvHD (68/199 vs 39/169, P = 0.019, Pcorr = 0.057). Multivariate logistic regression analysis in the MUD transplanted group showed that donor-recipient human leukocyte antigen (HLA) mismatch [odds ratio (OR) = 3.937, P = 0.001] and a lack of ACC haplotype in recipients (OR = 0.417, P = 0.013) played a significant role as independent risk factors of aGvHD grade > I. ACC carriers had higher proportions of FoxP3+ lymphocytes gated in CD4+ lymphocytes as compared with patients with other IL-10 haplotypes. It was seen at the time of hematological recovery (mean ± SEM: 3.80 ± 0.91% vs 2.06 ± 0.98%, P = 0.012) and 2 weeks later (5.32 ± 0.87% vs 2.50 ± 0.83%, P = 0.013); -592 C/A polymorphism was separately analyzed and it was found that AA homozygotes tended to have a higher incidence of aGvHD (8/15 vs 116/456, P = 0.034) and low proportions of FoxP3 CD4+ lymphocytes in blood (0.43 ± 0.22% vs 4.32 ± 0.71%, P = 0.051) measured 2 weeks after hematological recovery. Functional IL-10 polymorphism associated features influenced the risk of aGvHD with a positive effect of ACC on the pool of Treg in blood.

Haplotype analysis of interleukin-10 gene promoter polymorphisms in chronic hepatitis C infection: a case control study

High prevalence of hepatitis c virus (HCV) infection in some areas necessitates more investigations of the causative factors. Genetic factors that cause disruption in operation or secretion of interleukin 10 (IL-10), an anti-inflammatory cytokine, may play a role in the intensity of the disease. The aim of this study was to evaluate genetic variants of IL-10 gene polymorphisms in HCV patients and their relationship with HCV disease. Fifty HCV patients and the same number of healthy individuals who were referred to hepatitis clinic in Mashhad, northeast of Iran, were recruited. Genomic DNA was extracted from whole blood. Genotyping for IL-10 gene promoter polymorphisms in three positions (-1082 G>A, -819 C>T and -592 C>A) was conducted by amplification refractory mutation system-polymerase chain reaction. Haplotype analysis was performed using PHASE software. In a recessive analysis model of the -1082 position (GG vs. AA+AG), GG genotype was more common in patients (adjusted p = 0.02; OR = 4.66 [95% CI 1.31-16.35]). Also, ATA haplotype was more prevalent in HCV patients (adjusted p = 0.061; OR = 1.87 [95% CI 0.97-3.61]). Also, ATC/GCA diplotypes were more common in controls (adjusted p=0.002; adjusted OR = 0.27 [95% CI 0.11-0.63]). Although we found a possible association between IL-10 promoter polymorphisms and HCV infection, certain genotypes or diplotypes may confer a higher risk or susceptibility for developing HCV infection.

Impact of IL-10 (-1082) promoter-single nucleotide polymorphism on the outcome of hepatitis C virus genotype 4 infection

Immunoregulatory cytokines may influence the hepatitis C virus (HCV) infection outcome. This study aimed to determine the genotypic and allelic frequencies of the interleukin (IL)-10 (-1082) G/A polymorphism, and its association with chronicity or resolution of HCV genotype 4 infection in Egypt. The frequencies of different dimorphic polymorphisms based on single nucleotide substitution in chronic HCV patients (50) and resolved HCV patients (50) were: IL-10 (-1082) G/G 22 (44%) and 18 (36%), G/A 19 (38%) and 24 (48%), and A/A 9 (18%), and 8 (16%), respectively. In the sustained virologic response (SVR) (36) and spontaneously resolved subjects (14) groups, the frequencies were: IL-10 (-1082) G/G 11 (30.6%) and 7 (50%) G/A 18 (50%) and 6 (42.9%), A/A 7 (19.4%) and 1 (7.1%), respectively. An association between male gender and chronic hepatitis C outcome (P value 0.041) was found. However, no significant gender difference was found when we compared females versus males with elevated alanine transaminase (ALT) levels in the chronic HCV patient group (P value = 1).

CONCLUSION

No significant difference in the frequency of IL-10 single nucleotide polymorphism (SNP) at position 1082 was found between chronic and resolved HCV subjects.

Association of interleukin-10 polymorphisms with chronic hepatitis C virus infection in a case-control study and its effect on the response to combined pegylated interferon/ribavirin therapy

We conducted a case-control study involving 150 genotype 3 chronic hepatitis C virus (HCV) patients and 150 healthy controls to investigate the association of polymorphisms in the interleukin-10 (IL-10) gene with chronic HCV infection and the association of these polymorphic variants with the combination of pegylated interferon (Peg-IFN) and ribavirin therapy response. Our data revealed that the GG genotype of IL-10 –1082A/G exhibited significant association with genotype 3 chronic HCV infection compared to controls. Treatment response data also showed a significant increase in risk for the GG genotype of IL-10 –1082A/G in response-relapse patients or non-responder patients compared to sustained virological response patients. Further, a significant increase in risk was also revealed for the CC genotype of IL-10 –592A/C in response-relapse patients or non-responder patients compared to sustained virological response patients, suggesting a role of the GG genotype of IL-10 –1082A/G and CC genotype of IL-10 –592A/C in the treatment outcome of combined Peg-IFN/ribavirin therapy.

Association between TGFB1 915G/C polymorphism and susceptibility to chronic hepatitis C virus infection: A meta-analysis

The human transforming growth factor-β1 (TGF-β1) gene, namely TGFB1, contains several single-nucleotide polymorphisms (SNPs) and some of the polymorphic variants were shown to affect the TGF-β1 protein levels. A number of studies reported the association between 915G/C polymorphism and susceptibility to chronic hepatitis C virus (HCV) infection. However, the results were inconsistent. This meta-analysis was conducted to assess the association of TGFB1 915G/C polymorphism with susceptibility to chronic HCV infection. PubMed, ISI Web of Knowledge, ScienceDirect and Google Scholar databases were systematically searched up to August, 2013 to identify relevant studies. The pooled odds ratios (ORs) with their corresponding 95% confidence intervals (95% CIs) were calculated in 5 genetic comparison models (C vs. G, CC vs. GG, GC vs. GG, CC vs. GG+GC and CC+GC vs. GG). The Galbraith plot and subgroup analyses based on ethnicity, genotyping methods, sample size and fibrosis were performed to investigate possible sources of heterogeneity. A sensitivity analysis and assessment of publication bias were also conducted. Finally, 8 eligible case-control studies on TGFB1 915G/C polymorphism, including a total of 910 cases and 632 controls, were included in this meta-analysis. Overall, there was no evidence of any gene-disease association obtained from the subgroup analyses. Therefore, this meta-analysis demonstrated that there is no association between TGFB1 915G/C polymorphisms and susceptibility to chronic HCV infection.

IL28B and IL10R -1087 polymorphisms are protective for chronic genotype 1 HCV infection and predictors of response to interferon-based therapy in an East-Central European cohort

BACKGROUND

Previous studies have shown that single nucleotide polymorphisms (SNP) in IL28B and IL10R are associated with sustained virological response (SVR) in chronic hepatitis C patients treated with pegilated interferon plus ribavirin (P/R). The present study extends our earlier investigations on a large East-Central European cohort. The allele frequencies of IL28B and IL10R in genotype 1 HCV infection were compared with that of healthy controls for the purpose of examining the relationship between the polymorphisms and the SVR to P/R treatment.

METHODS

A total of 748 chronic HCV1 infected patients (365 male, 383 female; 18-82 years) and 105 voluntary blood donors as controls were enrolled. Four hundred and twenty HCV patients were treated with P/R for 24-72 weeks, out of them 195 (46.4%) achieved SVR. The IL28 rs12979860 SNP was determined using Custom Taqman SNP Genotyping Assays. The IL10R -1087 (also known as IL10R -1082 (rs1800896) promoter region SNP was determined by RT-PCR and restriction fragment length polymorphism analysis.

RESULTS

The IL28B CC genotype occurred with lower frequency in HCV patients than in controls (26.1% vs 51.4%, p<0.001). P/R treated patients with the IL28B CC genotype achieved higher SVR rate, as compared to patients with CT (58.6% vs 40.8%, p=0.002). The prevalence of IL10R -1087 GG genotype was lower in patients than in controls (31.8 % vs 52.2%, p<0.001). Among patients achieving SVR, the IL10R -1087 GG genotype occurred with higher frequency than the AA (32.0% vs 17.4%, p=0.013). The IL28B T allele plus IL10R A allele combination was found with higher prevalence in patients than in controls (52% vs 20.7%, p<0.001). The IL28B CC plus IL10R A allele combination occurred with higher frequency among patients with SVR than in non-responders (21.3% vs 12.8%, p=0.026). Both the IL28B CC plus IL10R GG and the IL28B CC plus IL10R A allele combinations occurred with lower frequency in patients than in controls.

CONCLUSIONS

In our HCV1 patients, both the IL28B CC and IL10R GG genotypes are associated with clearance of HCV. Moreover, distinct IL28B and IL10R allele combinations appear to be protective against chronic HCV1 infection and predictors of response to P/R therapy.

Relationship between IL-10 gene -1082A/G and -592C/A polymorphisms and the risk of hepatitis C infection: a meta-analysis

Increasing evidence suggests that interleukin-10 (IL-10) gene promoter polymorphisms may be associated with chronic hepatitis C virus (HCV) infection and HCV clearance. To more precisely estimate the association between these variants and the risk of HCV infection, we performed a meta-analysis of 26 studies describing the IL-10-1082A/G, -819C/T, -592C/A genotypes, including 4039 chronic HCV infection cases and 2902 controls. When compared with a healthy population, the -1082GG allele had a 43% increased risk of chronic HCV infection in combined populations (GG vs GA + AA: odds ratio (OR) = 1.433, 95% confidence interval (CI) = 1.052-1.952, P = 0.023). In subgroup analysis by ethnicity, a significant increased risk was associated with the -1082GG genotype in the Caucasian population (GG vs AA: OR = 1.390, 95% CI: 1.108-1.744, P = 0.004; GG vs GA + AA: OR = 1.621, 95% CI: 1.267-2.075, P = 0.000). However, no significant association was found in Asian, African or Chinese populations. Moreover, a higher distribution of -592A was found in the spontaneously recovered population (AA vs CC: OR = 0.585, 95% CI = 0.387-0.884, P = 0.011; AA + AC vs CC: OR = 0.738, 95% CI = 0.551-0.988, P = 0.041; AA vs AC + CC: OR = 0.788, 95% CI = 0.664-0.935, P = 0.006) than that in the chronic HCV infection population. In conclusion, the IL-10-1082GG allele may increase the risk of chronic HCV infection in Caucasian population, and people carrying the IL-10-592A allele are more likely to clear HCV spontaneously.

Single-nucleotide polymorphisms of IL-10 and IL-28B as predictors of the response of IFN therapy in HCV genotype 4-infected children

BACKGROUND AND AIMS

Single-nucleotide polymorphisms (SNPs) in the IL-10 gene (-1082 [rs1800896], -819 [rs3021097], and -592 [rs1800872]) and the IL-28B gene (rs12979860) in adults were shown to be associated with hepatitis C virus (HCV) clearance. The present study aimed to investigate the possible association of SNPs of IL-10 and IL-28B in predicting the treatment response of HCV genotype 4 in pediatric patients.

PATIENTS AND METHODS

A restriction fragment length polymorphism-polymerase chain reaction and real-time polymerase chain reaction techniques were used to genotype 34 pediatric patients with HCV genotype 4 for IL-10 and IL-28B SNPs, respectively. Patients received pegylated interferon-α/ribavirin for 48 weeks subdivided according to their response to treatment into responders and nonresponders; also, 20 healthy individuals served as controls.

RESULTS

A significant difference (P < 0.005) was observed in SNP of IL-28B rs12979860 frequencies between responders and nonresponders. In responders, CC genotype had greater frequency than CT and TT genotypes (60%, 30%, 10%), respectively, with C allele in its homozygous (CC) genotype more likely to respond to treatment than in its homozygous (TT) genotypes. SNPs of IL-10 at -819 (rs3021097) showed significant differences in their genotype frequencies between responders and nonresponders to therapy, and TT genotype had greater frequency in responders than CT and CC (55%, 20%, 25%), respectively. Genotypes with T allele (CT/TT) showed higher rates of response than those with no T allele (CC).

CONCLUSIONS

SNPs of the IL-28B gene at (rs12979860) CC genotype as well as the IL-10 gene SNPs at -819 (rs3021097)TT genotype can be used for predicting response to treatment before patients are prescribed the expensive pegylated interferon-α/ribavirin therapy.

Cytokines genes polymorphisms in chronic hepatitis C: impact on susceptibility to infection and response to therapy

BACKGROUND

Cytokines play a key role in the regulation of immune responses. In hepatitis C virus infection, the production of abnormal cytokine levels appears to contribute in the progression of the disease, viral persistence, and affects response to therapy. Cytokine genes polymorphisms located within the coding/regulatory regions have been shown to affect the overall expression and secretion of cytokines. The aim of the study was to evaluate the association of of IL28B rs12979860, TGF-β1-509, TNF-α 308, and IL-10-1082 polymorphisms with the susceptibility to hepatitis C virus genotype 4 infection and response to pegylated interferon-α and ribavirin therapy.

METHODS

IL28B, TGF-β1 and TNF-α genes polymorphisms were genotyped using polymerase chain reaction (PCR)-based restriction fragment length polymorphism assay while IL-10 gene polymorphism was detected by sequence specific primer-PCR in 220 healthy individuals and 440 hepatitis C infected patients (220 sustained virological response and 220 non-responder to combination therapy).

RESULTS

IL28 B CT and TT, TGF-β1 CT and TT and TNF-α AG and AA genotypes were significantly associated with susceptibility to hepatitis C infection and response to therapy. While no association was found between IL-10 gene polymorphism and susceptibility to HCV infection and response to treatment.

CONCLUSIONS

These results suggested that inheritance of IL28B CT and TT, TGF-β1 CT and TT and TNF-α AG and AA genotypes which appear to affect the cytokine production may be associated with susceptibility to HCV infection and resistance to combined antiviral therapy.

Polymorphisms in interleukin-10 and interleukin-28B genes in Egyptian patients with chronic hepatitis C virus genotype 4 and their effect on the response to pegylated interferon/ribavirin-therapy

BACKGROUND AND AIM

Recently, it has been suggested that single nucleotide polymorphisms (SNPs) in some cytokine genes may influence the production of the associated cytokines that affect the host immune response to pegylated interferon-α (Peg-IFN-α) with ribavirin (RBV) in hepatitis C virus (HCV) patients. The aim of the present study was to investigate the possible role of the SNPs of IL-10 and Il-28B and their serum levels in predicting the response to treatment of HCV-4.

METHODS

Egyptian patients were treated with Peg-IFN-α/RBV. A total of 100 HCV genotype 4-infected patients and 80 healthy control subjects were included in the present study. SNPs in the IL-10 (-592 A/C and -819 T/C) and IL-28B (rs8099917 T/G and rs12979860 C/T) genes and their serum levels were assessed. The IL-10-592-CC, IL-28-rs8099917-TT and IL-28-rs12979860-CC genotypes were significantly higher in responders than in non-responders.

RESULTS

Interestingly, the serum levels of IL-10 were significantly increased; in contrast, the serum levels of Il-28B were significantly decreased in HCV patients compared with normal patients. Polymorphisms in IL-28B are more sensitive (P < 0.001) than those in IL-10-592 (P = 0.03). However, the serum level of IL-10 is higher than that of IL-28, and this difference can serve as a prognostic marker using a receiver operator characteristic (ROC) analysis.

CONCLUSIONS

It can be concluded that SNPs in IL-28B and the serum levels of Il-10 and IL-28 may be promising predictors for HCV therapy.

Three polymorphisms in the IL-10 gene and the risk of HCV infection: a meta-analysis plus a Chinese Association Study involving 1140 subjects

The influence of an immunosuppressive cytokine, interleukin-10 (IL-10), on the outcome of hepatitis C virus (HCV) infection has been increasingly reported recently. A number of polymorphisms appear to control the level of IL-10 production. Among them, −592C/A, −819C/T and −1082G/A in the IL-10 gene are three most studied single nucleotide polymorphisms. To provide a more definitive conclusion about their association with the risk of HCV infection, a meta-analysis was performed by combining and summarizing a total of 17 studies. A biological justification for the choice of genetic model was provided. The results indicated no significant association between these IL-10 polymorphisms and the susceptibility to HCV infection [–592C/A: odds ratio (OR) 0·99, 95% confidence interval (CI) 0·78–1·25; –819C/T: OR 0·90, 95% CI 0·69–1·18; –1082G/A: OR 1·34, 95% CI 0·90–2·00]. However, this analysis did not account for the possible risk modifications by other factors, such as ethnicity and virus persistence. Therefore, the effects of ethnicity and virus persistence were investigated using Bayesian meta-regression and subgroup analysis. Finally, an extended case-control association study was conducted in a Chinese population involving 1140 subjects. Both serum level and genotype data of IL-10 −1082G/A were determined. As a result, a low prevalence of G allele was observed. Significantly higher IL-10 production was observed in HCV patients, especially patients with the GG genotype.

Hepatitis C virus spontaneous clearance: immunology and genetic variance

Hepatitis C virus (HCV) infection is one of the most common chronic viral infections in the world. Approximately 80-90% of acutely infected individuals develop persistent infection, which is a major risk for liver cirrhosis and liver cancer. However, a small portion of patients (10-20%) clear the virus. Clinical outcomes of HCV infection are determined by the interplay between the host immune response, and viral and environmental factors. In regulating immune responses, cytokines play an indispensable role that controls the underlying pathogenesis and the resulting outcome of HCV infection. Cytokines themselves are manipulated by polymorphisms in their genes. In fact, the majority of genetic variants that apparently confer a significant risk for chronic HCV infection have been localized in genes involved in cytokine synthesis and the ultimate immune response. So far, treatment strategies for HCV infection have remained controversial. Genotyping of different polymorphisms will aid clinical decision making for both current standard and personalized care. Genotyping can potentially be useful for future integration of other agents, which provides an opportunity for clinicians to personalize treatment regimens for HCV patients. This review summarizes findings of different studies on host immune responses after HCV infection and the association between cytokine gene polymorphisms and the likelihood of HCV clearance.

Differential regulation of the Let-7 family of microRNAs in CD4+ T cells alters IL-10 expression

MicroRNAs (miRNAs) are ∼22-nt small RNAs that are important regulators of mRNA turnover and translation. Recent studies have shown the importance of the miRNA pathway in HIV-1 infection, particularly in maintaining latency. Our initial in vitro studies demonstrated that HIV-1-infected HUT78 cells expressed significantly higher IL-10 levels compared with uninfected cultures. IL-10 plays an important role in the dysregulated cytotoxic T cell response to HIV-1, and in silico algorithms suggested that let-7 miRNAs target IL10 mRNA. In a time course experiment, we demonstrated that let-7 miRNAs fall rapidly following HIV-1 infection in HUT78 cells with concomitant rises in IL-10. To show a direct link between let-7 and IL-10, forced overexpression of let-7 miRNAs resulted in significantly reduced IL-10 levels, whereas inhibition of the function of these miRNAs increased IL-10. To demonstrate the relevance of these results, we focused our attention on CD4(+) T cells from uninfected healthy controls, chronic HIV-1-infected patients, and long-term nonprogressors. We characterized miRNA changes in CD4(+) T cells from these three groups and demonstrated that let-7 miRNAs were highly expressed in CD4(+) T cells from healthy controls and let-7 miRNAs were significantly decreased in chronic HIV-1 infected compared with both healthy controls and long-term nonprogressors. We describe a novel mechanism whereby IL-10 levels can be potentially modulated by changes to let-7 miRNAs. In HIV-1 infection, the decrease in let-7 miRNAs may result in an increase in IL-10 from CD4(+) T cells and provide the virus with an important survival advantage by manipulating the host immune response.

Is interleukin-10 gene polymorphism a predictive marker in HCV infection?

The clinical outcome of hepatitis C virus (HCV) infection varies between individuals - from spontaneous viral clearance and persistence without complication, to chronic hepatitis, cirrhosis and hepatocellular carcinoma. Also patterns of response to interferon-based anti-HCV therapy are different from person to person. This diversity may be affected by host genetic factors, including alterations in genes encoding cytokines. Interleukin-10, as an anti-inflammatory cytokine and immune response modulator, may influence on HCV infection susceptibility as well as spontaneous and treatment-induced HCV eradication. Moreover, it is stated that IL-10 has antifibrotic properties and play a role in progression of liver disease. This review summarized studies on interleukin-10 gene polymorphisms (mainly promoter SNPs at positions -1082(G/A), -819(C/T) and -592(C/A)), which may determine IL-10 production, regarding susceptibility to HCV infection, course of HCV-related liver disease (fibrosis, cirrhosis, hepatocellular carcinoma, ALT abnormalities), spontaneous viral elimination as well as hepatitis C treatment outcomes. Analysis of hereby summarized studies shows that it is difficult to unambiguously determine the importance of IL-10 polymorphism as a predictor of clinical outcome of hepatitis C and response to anti-HCV therapy before its beginning. Thus, future larger studies need to address these issues. Continuation of studies on interleukin-10 polymorphisms as well as identification of other candidate predictive markers in HCV infection has important practical implications and there is a chance that may contribute to reduce the scale of hepatitis C problem.

The pharmacogenetic background of hepatitis C treatment

Insufficiently treated hepatitis C virus (HCV) infection remains a major healthcare issue. Individual therapy responses vary considerably from spontaneous clearing of the virus to lethal conditions. Host genetics currently receives a major scientific and clinical interest as an important source of interindividual variability in treatment. Mainly the associations of interleukin 28B gene (IL28B) variants with decreased HCV clearance under standard therapy are considered as "state of the art" of hepatitis C pharmacogenetics. However, a search in PubMed identified 41 genes reportedly modulating the individual therapy response, e.g., genes coding for major histocompatibility complex (HLA), the tumor necrosis factor (TNF), interleukin 10 (IL10), other interferon coding genes than IL28B (e.g., IFNAR1, IFNAR2, IFNG), several components of downstream interferon signaling as well as genes modulating side effects of current anti-HCV therapeutics (e.g., SLC28A3, ITPA involved in ribavirin associated hemolytic effects or SLC6A4 and HTR1A involved in serotonin associated psychiatric side effects). Applying knowledge discovery methods from the area of data mining and machine-learning to this comprehensive set of HCV therapy modulating genes, relating the HCV genes to the world wide knowledge on genes given in the form of the Gene Ontology (GO) knowledge base, found that the relevant genes belong to the GO subcategories of "inflammatory response" and "immune response" and "response to virus". This complex approaches to the pharmacogenomics of HCV may serve to identify future candidates for a personalization of HCV therapy and structured approach to possible new therapeutic targets for the control of hepatitis C virus.

Tumor necrosis factor-alpha -308G/A polymorphism and risk of hepatocellular carcinoma in hepatitis C virus-infected patients

Tumor necrosis factor-alpha (TNF-α) is an important cytokine in generating an immune response against infection with hepatitis C virus (HCV). The functions of TNF-α may be altered by single-nucleotide polymorphisms (SNPs) in its gene structure. We hypothesized that SNPs in TNF-α may be important in determining the outcome of an HCV infection. To test this hypothesis, we investigated the role of the polymorphism -308G/A, which is located in the promoter region of the TNF-α gene, in the progression of HCV infection in Egyptian patients using a quantitative real-time polymerase chain reaction (qRT-PCR). The distribution of this polymorphism and its impact on the serum level of TNF-α was compared between 90 HCV-infected patients [45 with HCV-induced cirrhosis and 45 with HCV-related hepatocellular carcinoma (HCC)] and 45 healthy Egyptian volunteers without any history of liver disease. Our results showed that at the TNF-α -308 position, the G/G allele was most common (78.5%) in the study population, with the G/A and A/A alleles occurring less frequently (13.3% and 8.1%, respectively). Frequencies of G/G, G/A, and A/A genotypes were 87%, 7%, and 6% in patients with liver cirrhosis and were 94%, 4%, and 2% in patients with HCC, respectively. Serum levels of TNF-α were significantly higher in HCV-infected patients than in healthy controls, indicating that the TNF-α -308 polymorphism does not influence the production of TNF-α. The serum level of TNF-α was positively correlated with HCV infection. Taken together, these findings suggest that the TNF-α -308 polymorphism may not be a host genetic factor associated with the severity of HCV infection, but may be an independent risk factor for HCC.

Polymorphisms of toll-like receptors and their pathways in viral hepatitis

Toll-like receptors (TLRs) are an important part of the innate immune response to a variety of pathogens including hepatic viral infections. Activation of TLRs stimulates a complex intracellular signalling cascade that results in production of proinflammatory cytokines and interferons important for antiviral responses as well as induction of the adaptive arm of the immune system. There is substantial evidence for an important role for TLRs and TLR-mediated signalling in the pathogenesis and outcomes of hepatitis B and C in particular, but it might also influence responses to other viral hepatitis infections. Several single nucleotide polymorphisms (SNPs) of TLRs, relevant adaptor molecules and cytokines mediated by TLR signalling have been described that alter innate immune responses and have been implicated in a variety of human diseases including viral and other infections. There is now significant evidence that a number of TLR SNPs can affect various clinical outcomes in Caucasian patients with chronic HCV. However, the role of these polymorphisms in acute and other chronic hepatitis infections, including HBV as well as in non-Caucasian populations, has not been elucidated. In addition, results for SNPs downstream of TLR activation, such as in relevant cytokines, are inconsistent and their influence requires further investigation to determine the clinical significance of genetic variations in these mediators.

Genes and hepatitis C: susceptibility, fibrosis progression and response to treatment

Hepatitis C virus contact and infection show three different phenotypes: spontaneous viral clearance (SVC), chronic hepatitis C (CHC) and sustained virological response (SVR) following antiviral treatment. Many factors, including genetics, influence the evolution of these three phenotypes. We performed a literature search (PubMed) up to 31 January 2010 without language restriction to identify relevant studies on genes and hepatitis C. Additional studies were sought by reviewing the reference lists of the identified articles. Meta-analysis (using Meta-disk 1.4) was conducted to evaluate the association of single nucleotide polymorphism (SNP) in the IL28B region and SVR. The candidate gene approach showed strong relationships between human leucocyte antigen class II (DQB1(*) 0301 and DRB1(*) 1101) and SVC. A cirrhosis risk score involving 7 SNPs has been validated recently. The set of odds ratios of studies demonstrated an association between SNP (rs12987960/rs8099917) in the IL28B and SVR in CHC treated with peginterferon plus ribavirin (OR: 4.6; 95% CI: 2.9-7.3). The overall distribution of protective allele correlated with ethnic differences in SVR (Asians, Europeans, Hispanic and Afro-Americans) together with SVC, but not with fibrosis stage or viral load. These polymorphisms did not influence SVR in very-easy-to-treat patients such as genotype 2/3, rapid virological responders or patients with acute hepatitis C. While the genetic fingerprint for fibrosis progression remains elusive, IL28b polymorphism predicts SVC and SVR. However, nearly half of patients achieving SVR did not show favourable genotype. Further genetic signals are warranted to complete the puzzle of factors influencing hepatitis C.

Functional gene polymorphisms of interleukin-10 are associated with liver disease progression in Japanese patients with hepatitis C virus infection

OBJECTIVE

The inter-individual difference in response to liver injury appears to be important in the progression of liver fibrosis. Interleukin 10 (IL-10) is an anti-inflammatory cytokine, and several functional gene polymorphisms have been found. The aim of this study was to examine the possible association of IL-10 polymorphisms with the progression of liver fibrosis in hepatitis C virus (HCV)-related chronic liver disease patients.

METHODS

We examined the IL-10 -1087 A/G and -824 T/C gene polymorphisms in 184 Japanese patients with HCV-related chronic liver disease: 94 chronic hepatitis (CH) and 90 with liver cirrhosis (LC).

RESULTS

There were no significant differences in the genotype distributions or allele frequencies of IL-10 -824 T/C and -1087 A/G between the CH and LC groups. However, among the cirrhotic patients, the lower transcriptional allele, -824 T homozygotes had significantly lower serum albumin and platelet counts, and a higher Child-Pugh score than the -824 C carriers, and the lower transcriptional allele, -1087 A homozygotes had a higher ICG-R 15 compared with -1087 G carriers. Haplotype analysis of IL-10 -1087/-824 showed no significant difference between the CH and LC groups, but the combinations of AT and AC haplotypes (AT/AT, AT/AC and AC/AC) had a significantly higher ICG-R 15 than the GC carriers.

CONCLUSION

IL-10 lower transcriptional -824 T allele, -1087 A allele, and -1087/-824 haplotypes AT and AC are risk factors for the progression of liver fibrosis in HCV-related chronic liver disease.

The role of genetic markers in hepatitis C virus therapy: a major step for individualized care

It has been understood for some time that the treatment outcome of hepatitis C virus (HCV) infection is influenced by host genetic factors. Three independent genome-wide association studies have recently identified that a genetic variation in the IL28B gene [interferon-λ3 (IFN-λ3)] determines the outcome of IFN-α-based therapy in patients with genotype 1 chronic hepatitis C infection. This genetic polymorphism is also strongly associated with a higher likelihood of spontaneous clearance following acute hepatitis C infection. These results confirm the importance of specific host genetic markers in predicting outcome and treatment response. They also provide the framework and potential for a clinically relevant and meaningful pharmacogenomic approach to personalizing anti-HCV treatment.

Association of genetic variation in IL28B with hepatitis C treatment-induced viral clearance in the Chinese Han population

BACKGROUND

Genome-wide association studies have recently shown that the rs12979860 polymorphism in IL28B is associated with the response to chronic hepatitis C treatment. The aim of this study was to investigate whether rs12979860 could be used as a predictive marker for end-of-treatment response (ETR) or sustained virological response (SVR) in the Chinese Han population.

METHODS

The rs12979860 genotype was detected in 259 individuals infected with HCV by DNA sequencing. Among them, 120 patients were administered complete pegylated interferon-α and ribavirin combination therapy and 92 patients were followed for 24 weeks after the cessation of treatment and were divided into different groups according to outcomes of treatment.

RESULTS

The rs12979860 genotype CC was the primary genotype (87.64%, 227/259) and genotype TT was found in only one individual within this cohort. The patients with the rs12979860 genotype CC had higher rates of ETR (P=0.0044) and SVR (P=0.0046) than the patients with N-CC (CT or TT). In multivariate analyses, the rs12979860 genotype CC was associated with a substantial difference in rates of achieving ETR (odds ratio [OR] 8.983, 95% confidence interval [CI] 2.173-37.145; P=0.0024) and SVR (OR 24.298, 95% CI 2.27-259.90; P=0.0083).

CONCLUSIONS

This study demonstrated for the first time that the rs12979860 variation in IL28B could be a predictor of ETR and SVR in Chinese Han patients infected with HCV. The high frequency of the rs12979860 genotype CC might explain why the SVR rate is higher than that of the average global population.

Interleukin-10 gene polymorphisms in association with susceptibility to chronic hepatitis C virus infection: a meta-analysis study

A relationship between chronic hepatitis C virus (HCV) infection and interleukin-10 (IL-10) gene polymorphisms has been reported with controversial results in different studies. In an effort to solve this controversy, we quantitatively summarized ten studies on this relationship by means of meta-analysis. Our analysis included ten case-control studies with 992 cases of chronic HCV infection and 1,123 controls. Analyses were performed with STATA version 9.0. The results showed that the IL-10 -1082GG genotype significantly increased the risk for persistent HCV infection (AA vs. GG: OR = 0.680, 95% CI = 0.489-0.947, P = 0.022; AG vs. GG: OR = 0.608, 95% CI = 0.439-0.840, P = 0.003; GG vs. AG + AA: OR = 1.570, 95% CI = 1.160-2.123, P = 0.003), but no statistically significant differences were observed between cases and controls for IL-10 -819C/T and IL-10 -592C/A polymorphisms (P > 0.05). In conclusion, this meta-analysis suggested that the IL-10 -1082GG genotype was associated with increased susceptibility for chronic HCV infection.

Evolution of interferon-based therapy for chronic hepatitis C

Since 1986, interferon-alfa (IFN-α) monotherapy has been administered for patients with chronic hepatitis C (CHC). However, sustained response rate is only about 8% to 9%. Subsequent introduction of ribavirin in combination with IFN-α was a major breakthrough in the treatment of CHC. Sustained virological responses (SVRs) rate is about 30% in hepatitis C virus genotype 1 (HCV-1) patients, and is about 65% in HCV-2 or -3 patients. After 2000, pegylated interferon (PegIFN) much improved the rates of SVR. Presently, PegIFN-α-ribavirin combination therapy has been current standard of care for patients infected with HCV. In patients with HCV-1, treatment for 48 weeks is optimal, but 24 weeks of treatment is sufficient in HCV-2 or -3 infected patients. Clinical factors have been identified as predictors for the efficacy of the IFN-based therapy. The baseline factor most strongly predictive of an SVR is the presence of HCV-2 or -3 infections. Rapid virological response (RVR) is the single best predictor of an SVR to PegIFN-ribavirin therapy. If patients can't achieve a RVR but achieve a complete early virological response (cEVR), treatment with current standard of care can provide more than 90% SVR rate. HCV-1 patients who do not achieve an EVR should discontinue the therapy. Recent advances of protease inhibitor may contribute the development of a novel triple combination therapy.

Viral hepatitis: human genes that limit infection

Treatment response and susceptibility to chronic viral hepatitis C and B may be modified by host genetic factors. The majority of genetic variants that confer a significant risk have been localized in genes involved in immune response. However, many findings could not be replicated and almost none of the identified risk factors had a noticeable impact on clinical decisions. In contrast, recent findings in independent large genome wide association studies confirmed genetic variants in the interferon gamma gene locus as strong predictors of outcome with outstanding clinical relevance. This review gives an overview on significant genetic susceptibility factors for susceptibility and treatment outcome in chronic viral hepatitis C and B that have been identified by the classical candidate gene approach and genome wide studies and also highlights some recent findings on genetic factors for common adverse drug reactions.

Relationship between host genetic polymorphisms and the outcome of hepatitis C virus infection

Acute hepatitis C virus (HCV) infection can induce host innate and adaptive immune responses. Approximately 15%-25% of HCV-infected patients successfully eliminated the virus whereas the majority of these patients developed chronic liver disease, cirrhosis and hepatocellular carcinoma. Numerous studies have demonstrated that host genetic polymorphisms may lead to differences in host immune function and therefore influence the clinical outcome of HCV infection. This review briefly summarizes the relationship between host genetic polymorphisms and the outcome of HCV infection.

The most severe forms of type I autoimmune hepatitis are associated with genetically determined levels of TGF-beta1

We previously reported that paediatric (PAH) and adult (AAH) forms of type I autoimmune hepatitis (AH) have different HLA-associations and clinical outcome. In the present study we investigated the role of TGF-beta1 genetic polymorphisms in the different outcome of PAH and AAH. We found a significant increase of "high producer" 25GG genotype in PAH and 10CC in AAH. Low inflammation and low fibrosis in AAH was associated with the increase of codon 10CC (high producer) and codon 25CC (low producer) genotypes. The analysis in AAH of the two positions-haplotypes revealed that combined presence of 25GG and 10CC seems to neutralize the 10CC effect which remained in AAH having the 10CC(+)-25GG(-) haplotype. Altogether these results may explain, at least partially, the different clinical outcome of AAH and PAH.

Oct-1 is responsible for the C-33T polymorphism effect in the IL-4 promoter

IL-4 is a pleiotropic immunoregulatory cytokine secreted by Th2 subset of CD4(+) Th cells. Several transcription factors (TFs) have been determined with various degrees of certainty to bind the IL-4 promoter and to regulate its expression in human. To investigate the mechanisms responsible for phenotypic effects of the C-33T IL-4 promoter polymorphism, we performed a search of TFs binding to this promoter locus and discriminating the -33C and -33T alleles. In silico searches suggest few factors bind this region. Using an electromobility shift assay we found that Jurkat T cells contained proteins which specifically interacted with oligonucleotide probes, corresponding to the -33 region. Considerable binding differences between C and T alleles were demonstrated using competitive conditions, the proteins bound predominantly with -33C allele. We found that the transcription factor Oct-1 produced the major shifted complex. The binding of Oct-1 was not improved using activated nuclear extracts; however, we observed increases in other shifted complexes upon cell activation. We suppose that Oct-1 occupancy may compete for binding of activator proteins to closely or overlapped binding sites. Our findings suggest that the interplay between Oct-1 and unknown TFs may be responsible for the C-33T polymorphism effects.

Interleukin-10 promoter polymorphisms in hepatitis C patients with and without Schistosoma mansoni co-infection

BACKGROUND/AIM

Interleukin (IL-10) plays a major role in chronic hepatitis C virus (HCV) disease pathogenesis, in particular in Schistosoma mansoni (S. mansoni) co-infected patients. Given that interindividual variations in IL-10 production are influenced by functional polymorphisms in the IL-10 gene promoter, we determined the frequencies of common (-1082, -819 and -592) IL-10 promoter polymorphisms in chronic HCV patients with and without S. mansoni co-infection and healthy controls, and investigated their association with the degree of histological activity index (HAI) and response to interferon-ribavirin therapy.

METHODS

Genomic DNA from 99 patients and 62 healthy controls, born in the same geographical hyperendemic area, was studied by the polymerase chain reaction, followed by restriction enzyme digestion. Sera were assessed for S. mansoni antibodies.

RESULTS

The frequencies of IL-10 polymorphisms at positions -1082, -819 and -592 from the transcription start site were comparable between HCV patients and controls, as well as between HCV mono-infected and either S. mansoni co-infected patients or controls. The grade of inflammation and the stage of fibrosis showed no association with IL-10 polymorphisms. The frequencies of S. mansoni co-infection and IL-10 genotypes/haplotypes were insignificantly different between non-responders and responders to combination therapy. No effect of other factors like age, gender, HAI group scores and serum alanine aminotransferase and aspartate aminotransferase levels was observed on response to therapy in our patients.

CONCLUSION

Our findings suggest that common IL-10 (-1082, -819 and -592) genotypes/haplotypes do not influence the degree of HAI and response to combination therapy or susceptibility to HCV infection with and without S. mansoni co-infection.

An assessment of a TNF polymorphic marker for the risk of HCV infection: meta-analysis and a new clinical study design

A number of studies have investigated the association between TNF-alpha -308G/A polymorphism and the risk of HCV infection; the results of these studies are conflict, however. To provide a more definitive conclusion, a meta-analysis combining and summarizing 12 studies was performed. The Mantel-Haenszel and DerSimonian-Laird methods were employed in traditional fixed effects and random effects meta-analysis, respectively. The capability of a Bayesian approach was highlighted in the estimation of a pooled odds ratio and 95% confidence interval, as well as in the calculation of a sample size for the new study design. Heterogeneity and publication bias across the studies were also explored. The results of the meta-analysis (OR=1.179, CI=0.833-1.649) suggest no significant association between TNF-alpha -308G/A polymorphism and susceptibility to HCV infection in the combined populations. However, there was evidence indicating a possible impact of ethnicity (Asian vs. non-Asian populations) on the association evaluated here (beta(ethnicity)=0.293+/-0.271). While the power of existing Asian studies was insufficient to make a statistical statement, the sample size of a new clinical study was estimated (500 subjects with 80% statistical power) for further assessment of an association between TNF-alpha -308G/A polymorphism and risk of HCV infection in Asians.