Cytokine gene polymorphisms in patients infected with hepatitis B virus

Polymorphisms of tumor necrosis factor-alpha and hepatocellular carcinoma risk: a HuGE systematic review and meta-analysis

BACKGROUND

Studies investigating the associations between tumor necrosis factor-alpha (TNFA) polymorphisms and hepatocellular carcinoma (HCC) risk report conflicting results. We conducted a meta-analysis to assess the association between TNFA gene TNFA-308(G/A), TNFA-238(G/A), TNFA-863(C/A), TNFA-857(C/T), TNFA-1031 (T/C) polymorphisms and HCC susceptibility.

METHODS

Two investigators independently searched the Medline, Embase, CNKI, and Chinese Biomedicine Database. Summary odds ratios (ORs) and 95% confidence intervals (95% CIs) for TNFA polymorphisms and HCC were calculated in a fixed-effects model (the Mantel-Haenszel method) and a random-effects model (the DerSimonian and Laird method) when appropriate.

RESULTS

This meta-analysis included 17 case-control studies, which included 2,357 HCC cases and 3,161 controls. Overall, the variant genotypes AA/AG of -308G/A were associated with a significantly increased HCC risk, when compared with GG genotype (AA vs. GG, OR=1.97, 95%CI=1.01-3.83; AG vs. GG, OR=1.88, 95%CI=1.23-2.88; AA/AG vs. GG, OR=1.80, 95%CI=1.19-2.72). When stratifying for ethnicity, significantly elevated HCC risk was found among Asians. Moreover, similar results were observed between TNFA-238G/A, TNFA-863C/A polymorphisms and HCC risk among Asians (for -238G/A, AG vs. GG OR=1.63, 95%CI=1.17-2.26, AA/AG vs. GG OR=1.61, 95%CI=1.16-2.24; for -863 C/A, AC vs. CC OR=1.72, 95%CI=1.03-2.88, AA/AC vs. CC OR=1.71, 95%CI=1.02-2.86), while no associations were observed between TNFA-857C/T, TNFA-1031T/C polymorphisms and HCC susceptibility.

CONCLUSIONS

This meta-analysis shows that TNFA-308G/A, TNFA-238G/A and TNFA-863C/A polymorphisms may be associated with HCC among Asians. TNFA-857C/T and TNFA-1031T/C polymorphisms were not detected to be related to the risk for HCC.

A genome-wide association study of chronic hepatitis B identified novel risk locus in a Japanese population

Hepatitis B virus (HBV) infection is a major health issue worldwide which may lead to hepatic dysfunction, liver cirrhosis and hepatocellular carcinoma. To identify host genetic factors that are associated with chronic hepatitis B (CHB) susceptibility, we previously conducted a two-stage genome-wide association study (GWAS) and identified the association of HLA-DP variants with CHB in Asians; however, only 179 cases and 934 controls were genotyped using genome-wide single nucleotide polymorphism (SNP) arrays. Here, we performed a second GWAS of 519 747 SNPs in 458 Japanese CHB cases and 2056 controls. After adjustment with the previously identified variants in the HLA-DP locus (rs9277535), we detected strong associations at 16 loci with P-value of <5 × 10(-5). We analyzed these loci in three independent Japanese cohorts (2209 CHB cases and 4440 controls) and found significant association of two SNPs (rs2856718 and rs7453920) within the HLA-DQ locus (overall P-value of 5.98 × 10(-28) and 3.99 × 10(-37)). Association of CHB with SNPs rs2856718 and rs7453920 remains significant even after stratification with rs3077 and rs9277535, indicating independent effect of HLA-DQ variants on CHB susceptibility (P-value of 1.52 × 10(-21)- 2.38 × 10(-30)). Subsequent analyses revealed DQA1*0102-DQB1*0604 and DQA1*0101-DQB1*0501 [odds ratios (OR) =0.16, and 0.39, respectively] as protective haplotypes and DQA1*0102-DQB1*0303 and DQA1*0301-DQB1*0601 (OR = 19.03 and 5.02, respectively) as risk haplotypes. These findings indicated that variants in antigen-binding regions of HLA-DP and HLA-DQ contribute to the risk of persistent HBV infection.

Single nucleotide polymorphism at exon 7 splice acceptor site of OAS1 gene determines response of hepatitis C virus patients to interferon therapy

BACKGROUND AND AIM

Response to interferon therapy and disease progression in hepatitis C virus (HCV) infected patients differs among individuals, suggesting a possibility of a contribution of host genetic factors. 2'-5'-oligoadenylate synthetase 1 (OAS1), an important component of the innate immune system with a proven antiviral function, may therefore have a relationship with the response to interferon therapy and clinical course of HCV disease. Our aim was to determine the frequency of single nucleotide polymorphism (SNP) at exon 7 splice acceptor site (SAS) of the OAS1 gene in relation to the interferon response and status of HCV infection.

METHODS

A 203 bp fragment containing exon 7 SAS was amplified in 70 HCV chronic patients and 50 healthy controls. SNP was examined using restriction fragment length polymorphism (RFLP) genotyping method. Correlations of SNP genotypes with response to interferon and clinical status of patients were statistically analyzed.

RESULTS

There was an increasing trend of response from AA to AG to GG genotypes (P = 0.007). Genotype AA was associated with non-response to interferon and higher degree of liver fibrosis (P = 0.05). Multivariate analysis showed this SNP as independent and a significant determinant of the outcome of interferon therapy (odds ratio 4.913 [95% confidence interval 1.365-8.2], P = 0.006).

CONCLUSIONS

This is the first study to show a significant association between the functional SNP at exon 7 SAS of OAS1 gene and the viral response to interferon in chronic HCV patients. Patients with AA genotype were associated with progressive HCV disease and viral resistance to interferon therapy. This OAS SNP is a potential bio-marker to predict IFN response in chronic hepatitis C patients.

Tumor necrosis factor alpha 308 G/A polymorphism and hepatocellular carcinoma risk in a Chinese population

BACKGROUND

The genetic basis of susceptibility to hepatocellular carcinoma (HCC) is poorly understood. Tumor necrosis factor alpha (TNF-α) is a cytokine that may act as an endogenous tumor promoter. The association between TNF-α 308 G/A polymorphism and HCC risk remains unclear.

AIM

The aim of this study was to investigate the association between TNF-α 308 G/A polymorphism and HCC risk in a Chinese population.

METHODS

The study population consisted of 88 patients with documented HCC and 88 healthy controls. The gene polymorphism of TNF-α was analyzed by polymerase chain reaction-restriction fragment length polymorphism assay.

RESULTS

HCC patients had a significantly lower frequency GG (odds ratio=0.36; 95% confidence interval=0.13, 0.94; p=0.04) and G allele (odds ratio=0.58; 95% confidence interval=0.37, 0.90; p=0.01) than healthy controls. When stratifying for tumor size and cirrhosis, no statistically significant results were found.

CONCLUSION

This study suggested that TNF-α -308GG and G allele were associated with a modest decrease in the risk of HCC in Chinese population.

Molecular genetics of HBV infection

HBV has evolved a unique life cycle that results in the production of enormous viral loads during active replication without actually killing the infected cells directly. Two of the key events in the viral life cycle of HBV involve firstly the generation of a covalently closed circular (ccc)DNA transcriptional template, either from input genomic DNA or newly replicated capsid-associated DNA, and secondly, reverse transcription of the viral pregenomic (pg)RNA to form progeny HBV DNA genomes. New data are emerging regarding the epigenetic control of cccDNA, which might represent another key factor involved in the pathogenesis and natural history of the disease. Because HBV uses reverse transcription to copy its genome, mutant viral genomes emerge frequently. Particular selection pressures, both endogenous (host immune clearance) and exogenous (vaccines and antiviral drugs), readily select out these escape mutants. The particular viral mutations or combination of mutations that directly affect the clinical outcome of infection are not known; however, four major 'pathways' of antiviral drug resistance-associated substitutions have now been identified. Further studies are clearly needed to identify the pathogenetic basis and clinical sequelae arising from the selection of these particular mutants. In the clinical context of antiviral drug resistance, treating physicians need to adopt therapeutic strategies that effectively control viral replication. Finally, the role of host genetics in influencing the outcome of HBV disease in the context of natural history and therapy is beginning to aid understanding in pathogenesis and, when this knowledge is linked to pathogen-specific databases, this should translate into more individualized patient care.

Strong influence of human leukocyte antigen (HLA)-DP gene variants on development of persistent chronic hepatitis B virus carriers in the Han Chinese population

Chronic hepatitis B virus (HBV) infection is a major health issue, especially in Asia. A recent genome-wide association study (GWAS) implicated genetic variants in the human leukocyte antigen (HLA)-DP locus associated with chronic hepatitis B in Japanese and Thai populations. To confirm whether the polymorphisms at the HLA-DP genes are associated with persistent chronic HBV infection in Han Chinese, we conducted an independent case-control study using 521 persistent chronic HBV carriers and 819 controls that included 571 persons with HBV natural clearance and 248 never HBV-infected (healthy) individuals. Eleven single nucleotide polymorphisms (SNPs) in a region including HLA-DPA and HLA-DPB and an adjacent SNP in strong linkage disequilibrium (LD) with a neighboring HLA-DR13 locus were genotyped using the TaqMan SNP genotyping assay. Eleven variants at HLA-DP showed a strong association with persistent chronic HBV carrier status (P = 1.82 × 10(-12) to 0.01). We also stratified the analysis by HBV clearance status to test the association between these polymorphisms and HBV natural clearance; similar results were obtained (P = 2.70 × 10(-11) to 0.003). Included SNPs define highly structured haplotypes that were also strongly associated with HBV chronic infection (block 1: odds ratio [OR] = 0.54, P = 8.73 × 10(-7) ; block 2: OR = 1.98, P = 1.37 × 10(-10) ). These results further confirm that genetic variants in the HLA-DP locus are strongly associated with persistent HBV infection in the Han Chinese population.

The impact of biologic response modifiers on hepatitis B virus infection

INTRODUCTION

The biologic response modifiers are a diverse group of medications that have emerged over the last decade. They target pro-inflammatory cytokines or cell surface molecules that drive illnesses such as rheumatoid arthritis. Despite the greater control afforded they have also ushered in a new spectrum of side effects. As the same immunologic machinery that helps control infections such as HBV contributes to the pathogenesis of rheumatologic diseases, persistence or reactivation of the virus remains an evolving concern.

AREAS COVERED

A systemic literature review was performed using the PubMed and Medline databases (1996 to January 2010) searching for the index term 'Hepatitis B' combined with the terms 'tumor necrosis factor', 'B cell', 'rituximab', 'IL-1', 'anakinra', 'IL-6', 'tocilizumab', 'CTLA-4', and 'abatacept'. All relevant articles in English were reviewed and secondary references of interest were also retrieved. This paper addresses the role of the various cytokines and cluster of differentiation molecules in controlling HBVinfection and the currently known effect that the biologic response modifiers have on viral control by the host immune response.

EXPERT OPINION

The risk of HBV reactivation is greatest in HBsAg positive patients. These patients should start antiviral therapy one week before receiving a biologic response modifier. The risk of HBV reactivation in HBsAg negative patients appears very low but when HBsAb titers are low use of rituximab or TNF-α antagonists may increase the risk of reactivation.

A meta-analysis of the relation of polymorphism at sites -1082 and -592 of the IL-10 gene promoter with susceptibility and clearance to persistent hepatitis B virus infection in the Chinese population

BACKGROUND

Up to now, many publications about the Chinese population have evaluated the correlation between interleukin-10 (IL-10) -1082 and -592 polymorphisms and persistent hepatitis B virus (HBV) infection. However, the results remain inconclusive. In order to resolve this conflict, a meta-analysis was performed.

METHODS

Seven studies were included and dichotomous data are presented as the odds ratio (OR) with a 95% confidence interval (CI).

RESULTS

The results of our study suggest that carriers of the IL-10 -592A allele were more likely to clear HBV spontaneously in the Chinese pooled population (A vs. C: OR = 0.799, 95% CI = 0.678-0.941, P = 0.007; AC vs. AA: OR = 1.343, 95% CI = 1.017-1.684, P = 0.011; AA vs. AC + CC: OR = 0.736, 95% CI = 0.594-0.912; AA + AC vs. CC: OR = 0.588, 95% CI = 0.408-0.848, P = 0.004) and the IL-10 -1082A allele was associated with significantly reduced persistent HBV infection risk in Chinese (A vs. G: OR = 0.701, 95% CI = 0.494-0.996, P = 0.047; AA vs. GG + GA: OR = 0.684, 95% CI = 0.476-0.982, P = 0.040).

CONCLUSIONS

Persistent HBV infection susceptibility is associated with the gene polymorphism IL-10 -1082GA in the Chinese population and the clearance of HBV is associated with the gene polymorphism IL-10 -592CA in the Chinese population.

Epidermal growth factor +61 G/A polymorphism and the risk of hepatocellular carcinoma in a Chinese population

BACKGROUND

Chronic hepatitis B virus (HBV) infection is a risk factor of hepatocellular carcinoma (HCC) in China. Epidermal growth factor (EGF) plays an important role in tumorigenesis. The association between EGF +61 G/A polymorphism and the risk of HCC is still controversial and ambiguous.

AIM

The objective of this study was to investigate the association between EGF +61 G/A polymorphism and the risk of HCC in a Chinese population.

METHODS

A hospital-based case-control study was designed in a Chinese population. EGF +61 G/A polymorphisms were determined in 120 chronic HBV-infected HCC patients, 120 chronic HBV-infected cirrhotic patients, and 120 healthy controls. The genotype frequency of this polymorphism was determined by using a polymerase chain reaction-restriction fragment length polymorphism assay.

RESULTS

EGF +61 GG (odds ratio=2.76, 95% confidence interval=1.03, 7.38; p=0.04) and G allele frequencies (odds ratio=1.59, 95% confidence interval=1.08, 2.34; p=0.02) in the HCC group were higher than those in the cirrhosis group. EGF +61 A and G allele frequencies in healthy subjects were 28.8% and 71.2%. No relationship between EGF +61 G/A gene polymorphism and HCC risk was found among our recruited HCC patients and healthy controls.

CONCLUSION

This study suggests that EGF +61 GG genotype is associated with a higher risk of chronic HBV-infected HCC in the Chinese population.

The TNF-α, IL-1B and IL-10 polymorphisms and risk for hepatocellular carcinoma: a meta-analysis

OBJECTIVE

TNF-α-308 G/A, TNF-α-238 G/A, IL-1B-31 T/C, IL-1B-511 C/T, and IL-10-1082 G/A polymorphisms have been reported to influence the risk for hepatocellular carcinoma (HCC) in many studies; however, the results still remains controversial and ambiguous. The aim of this study was to determine more precise estimations for the relationship between TNF-α, IL-1B, and IL-10 polymorphisms and the risk for HCC by meta-analysis.

METHODS

Electronic searches for all publications were conducted on associations between these variants and HCC in several databases through September 2010. Odds ratios (OR) with 95% confidence intervals (95% CI) were calculated to estimate the strength of this association in a random-effect model. Twenty studies were identified, involving 2,763 HCC patients and 4,152 controls.

RESULTS

This meta-analysis showed significant association between TNF-α-308 polymorphism and HCC (AA + GA vs. GG: OR = 1.74, 95% CI = 1.12-2.72). In Caucasian and Asian subgroups, OR values (95% CI) were 1.49 (0.58-3.82) and 1.84 (1.06-3.20), respectively. While the ORs for TNF-α-238 G/A, IL-1B-31 T/C, -511 C/T and IL-10-1082 G/A polymorphisms and HCC were 1.37 (0.95-2.00), 1.24 (0.99-1.55), 1.12 (0.66-1.88) and 0.91 (0.74-1.12), respectively. The sensitivity analysis further strengthened the overall strong positive correlations. No publication bias was observed in this study.

CONCLUSIONS

TNF-α-308 G/A polymorphism is assumed to confer a higher risk for HCC, especially in Asian population. TNF-α-238 G/A, IL-1B-31 T/C, -511 C/T, and IL-10-1082 G/A polymorphisms were not detected to be related to the risk for HCC.

Interleukin 6 promoter polymorphisms influence the outcome of chronic hepatitis C

Host genetic variation may affect the outcome of chronic viral hepatitides, favoring viral clearance and/or modulating the inflammatory response to persistent infection. Our aims were to assess whether interleukin 6 (IL-6) promoter polymorphisms are associated with chronic hepatitis C virus (HCV) infection and to clarify the role of IL-6 haplotypes in facilitating progressive disease. The study included 424 Italian patients (233 males, median age 53 years) affected by HCV chronic infection. IL6 -1363, -597, -572, -174, and +2954 polymorphic loci were assayed by means of restriction fragment length polymorphism. Three hundred forty-four healthy Italian blood donors (245 males, median age 50 years) served as controls. Comparing patients and controls analysis of molecular variance was highly significant (p < 0.0001); at a locus by locus approach, the frequencies of minor alleles in the -1363 (p < 0.02), -597 (p < 0.02), and -174 (p < 0.01) polymorphisms were confirmed to be less represented in patients than in controls. Carrying the wild-type G allele at the -597 and -174 loci identified an unfavorable haplotype; carrying the minor allele in one/both loci identified an indifferent/favorable haplotype. Male patients carrying two unfavorable haplotypes had the highest adjusted mean ± standard error Ishak staging score (3.56 ± 0.19), while females carrying one or no unfavorable haplotypes had the lowest (2.69 ± 0.21); the remaining patients had an intermediate value (3.12 ± 0.13, p < 0.01). In conclusion, IL-6 promoter polymorphisms influence the development of chronic HCV infection. With the permissive effect of male gender, haplotypes represented by the wild-type allele for -597 and -174 loci appear to favor a worse evolution of the disease.

Tumour necrosis factor-alpha polymorphisms and hepatocellular carcinoma: a meta-analysis

The genetic basis of susceptibility to hepatocellular carcinoma (HCC) is poorly understood. To summarize the quantitative association between polymorphisms of the tumour necrosis factor-alpha (TNFA) gene and HCC, a meta-analysis of relevant studies was performed. Ten case-control studies involving 1421 HCC cases were identified from the Medline, Embase and Current Contents databases. Combined results based on all studies showed that patients with HCC had a significantly lower frequency of the TNFA gene polymorphism -308GG than healthy controls. When stratifying for race, results were similar among Asians and Caucasians. When comparing with hepatitis B virus infection cases, no statistical association was found. This meta-analysis suggests that TNFA -308GG gene polymorphism is associated with a modest decrease in the risk of HCC.

Persistent effect of IFNAR-1 genetic polymorphism on the long-term pathogenesis of chronic HBV infection

Genetic polymorphism of IFNAR-1 plays a large role in determining the clearance or chronicity after hepatitis B virus (HBV) exposure. However, it is not clear whether type I interferon receptor-1 (IFNAR-1) variations continuously exert their effects to influence the final outcomes following HBV chronicity, including acute-on-chronic hepatitis B liver failure (ACLF-HBV), chronic hepatitis B (CHB), liver cirrhosis (LC), and hepatocellular carcinoma (HCC). Here we report that these four potential outcomes of chronic HBV infection are strongly associated with IFNAR-1 polymorphisms through a hospital-based case-control study of 663 cases. ACLF-HBV and HCC were each compared with CHB+LC. In comparison with the G/G genotype, the C/G and C/C genotypes at both single-nucleotide polymorphism (SNP) sites (rs1012335 and rs2257167) showed significant susceptibility to ACLF-HBV (the highest odds ratio [OR] reached 2.374; 95% CI = 1.488, 3.788; p < 0.001 for the C/G genotype at rs2257167), as well as HCC (OR = 2.475; 95% CI = 1.435, 4.426; p < 0.001 for the C/C genotype at rs1012335). The C allele at both loci was a susceptibility allele for ACLF-HBV and HCC, with the highest ORs reaching 1.653 (95% CI = 1.233, 2.216; p < 0.01 at rs1012335) in the ACLF-HBV group, and 1.659 (95% CI = 1.274, 2.159; p < 0.01 at rs1012335) in the HCC group. A strongly linked disequilibrium was also found within these two alleles (p < 0.001). Our research indicates that genetic polymorphisms of IFNAR-1 not only contribute to the determination of clearance or chronicity in the early stages of HBV exposure, but they also persistently influence pathogenesis over the long-term process of chronic HBV infection.

Association between hepatitis B viral burden in chronic infection and a functional single nucleotide polymorphism of the PDCD1 gene

BACKGROUND

PD-1, encoded by PDCD1, is highly expressed on virus-specific T cells and plays critical roles in modulating anti-virus immune responses in chronic viral infection. It is unknown, however, whether polymorphisms of the PDCD1 are associated with viral clearance during chronic viral infections.

METHODOLOGY AND PRINCIPAL FINDINGS

Here, we used the polymerase chain reaction-restriction fragment length polymorphism method to genotype two single nucleotide polymorphisms (SNPs) of PDCD1 in 502 patients with chronic hepatitis B virus (HBV) infection and 359 healthy controls to determine the association between PDCD1 genotypes and serum viral load as well as the risk of chronic infection. Our results showed that although neither the P7209(C/T) SNP site nor the P8737(A/G) site was associated with the risk of chronic HBV infection, the P7209 (T) allele in intron 4 is significantly associated with lower viral burden in the blood. Using a luciferase reporter assay, we demonstrated that the P7209 (T) allele creates a negative cis-element for gene transcription.

CONCLUSIONS AND SIGNIFICANCE

Our data provide the first evidence that PDCD1 polymorphisms is a genetic factor in pathogenesis of chronic viral infection and reveal the functional significance of the P7209 SNP of the PDCD1.

Use of tumor necrosis factor alpha inhibitors in hepatitis B surface antigen-positive patients: a literature review and potential mechanisms of action

As a class, tumor necrosis factor (TNF)-alpha inhibitors have provided clinicians significant control over chronic inflammatory diseases. With their widespread use has come the emergence of new side effects such as the reactivation of latent infections. One such infection that may reactivate is the hepatitis B virus (HBV). It is currently unknown if HBV reactivation is a class effect or attributable to a particular TNF-alpha inhibitor. To answer this question, a comprehensive literature review to identify trends in related cases was performed. A systemic literature review was performed using the PubMed and Medline databases (1996 to January 2010) searching for the index term "Hepatitis B" combined with the terms "tumor necrosis factor," "TNF-alpha inhibitors," "etanercept," "adalimumab," "certolizumab," and "golimumab." All relevant articles in English were reviewed, and secondary references of interest were also retrieved. Thirty-five cases with hepatitis B surface antigen (HBsAg) positivity known prior to initiation of TNF-alpha inhibitors were identified. Infliximab was used in 17 cases, etanercept in 12 cases, and adalimumab in 6 cases. All six cases of clinically symptomatic hepatitis were associated with infliximab therapy. Infliximab was associated with the most cases of greater than 2-fold increase in alanine aminotransferase (six of nine cases) and greater than 1,000-fold increase in HBV DNA load (three of four). The two deaths reported occurred with infliximab therapy. Potential mechanisms of action for the reported observations include differences in molecular design, route of administration, and potency in clearing TNF-alpha. In patients with a positive HBsAg prior to starting a TNF-alpha inhibitor, infliximab has the most reported cases associated with HBV reactivation. While such reactivation may be due to a variety of reasons, clinicians prescribing TNF-alpha inhibitors to HBsAg-positive patients should consider prophylactic antiviral therapy and close monitoring for any clinical or serological evidence of hepatitis.

Relationship between IL-10 gene promoter polymorphisms and outcome of hepatitis B virus infection

AIM: To investigate the relationship between interleukin-10 (IL-10) gene promoter polymorphisms at positions -1082 and -819 and the outcome of hepatitis B virus (HBV) infection.

METHODS: TaqMan SNP genotyping and sequencing assays were employed to determine the distribution of genotypes and alleles of the IL-10 gene at positions -1082 and -819 in 187 healthy control subjects, 94 self-limited HBV patients, 130 patients with chronic hepatitis B, 119 patients with HBV-induced liver cirrhosis and 170 patients with HBV-related hepatocellular carcinoma (HCC).

RESULTS: Of the 700 subjects, 82.29% had the AA genotype, 16.00% had the AG genotype, and 1.71% had the GG genotype in the IL-10 gene promoter at position -1082. The frequencies of A and T alleles were 90.29% and 9.71%, respectively. The TT, TC and CC genotypes in the IL-10 gene promoter at position -819 accounted for 41.43%, 48.14%, and 10.43%, respectively. The frequencies of T and C alleles were 65.64% and 34.36%, respectively. There were no significant differences in genotype or allele distribution at the two positions among different groups. IL-10-1082 AG genotype and G allele decreased the risk of chronic hepatitis B and cirrhosis. IL-10-819 TC genotype was associated with a decreased risk of HCC. IL-10-819 CC genotype and C allele decreased the risk of chronic hepatitis B, cirrhosis and HCC. AC haplotype decreased the risk of cirrhosis and HCC, while GC haplotype decreased the risk of chronic hepatitis B and cirrhosis. The frequency of IL-10-819 C was significantly higher in patients with HBV DNA levels < 103 copies/mL than those with HBV DNA levels ≥ 10³ copies/mL (P = 0.025). No significant differences were noted in genotypes or allele frequencies among HCC or cirrhosis subjects with different grades of Child-Pugh classification, different levels of alpha-fetoprotein or different HBsAg status.

CONCLUSION: IL-10-1082 AG genotype and G allele, IL-10-819 TC and CC genotype and C allele, as well as IL-10-1082/-819 AC and GC haplotypes may play a protective role in the disease progression after HBV infection. IL-10-819 C allele may contribute to virus elimination in HBV-infected patients.

Association of candidate susceptible loci with chronic infection with hepatitis B virus in a Chinese population

A number of genetic loci have been proposed to be associated with persistent hepatitis B virus (HBV) infection. This study aimed to evaluate the association and interaction of susceptible genes with HBV persistence in a Chinese population. A total of 17 polymorphisms in 9 candidate genes were studied in 361 Chinese chronic hepatitis B patients and 304 patients who recovered spontaneously. Distributions of susceptible polymorphisms were examined in healthy Chinese and Caucasian populations. Gene-gene interactions were tested by the multifactor dimensionality reduction (MDR) method. The TNF -308 G/G genotype and G allele, IL-10RB codon 47 A allele, and MCP-1 -2518 G/G genotype and G allele were more frequent in patients than controls (P < 0.01, after multiple corrections Pc < 0.05), while the frequencies of TNF -308 A/G genotype and IL-10 -592 A/A genotype were significantly higher in controls than in the patient group (Pc < 0.05). The frequencies of the risk allele MCP-1 -2518 G and CTLA4 6230 G were much higher in Chinese than in the Caucasian groups (P < 0.001). An interaction between CCR5 -2459, TNFA -863, IL-10RB codon 47, and MCP-1 -2518 was detected by MDR (P = 0.001). The results indicate that genetic determinants may affect the outcome of HBV infection in both independent and synergic manners. J. Med. Virol. 82:371-378, 2010. (c) 2010 Wiley-Liss, Inc.

Tumor necrosis factor-alpha-308A allele may have a protective effect for chronic hepatitis B virus infection in Mongoloid populations

OBJECTIVES

Previous studies on the tumor necrosis factor-alpha (TNF-alpha)-308 gene promoter polymorphism in chronic hepatitis B virus (HBV) infection have reported conflicting results.

METHODS

We carried out a meta-analysis of 21 studies in relation to the TNF-alpha-308 gene promoter, involving a total of 4230 chronic HBV infection cases and 2905 controls.

RESULTS

The overall meta-analysis indicated that -308A heterozygotes (GA) had a significant 27% decreased risk of developing chronic hepatitis B (CHB) (odds ratio (OR) 0.73; 95% confidence interval (CI) 0.57-0.93; p=0.012). For -308A allele homozygotes (AA) and carriers (GA+AA), the pooled odd ratios both indicated a significantly decreased risk of CHB (OR 0.28; 95% CI 0.19-0.43; p=0.0001; and OR 0.70; 95% CI 0.55-0.89; p=0.004, respectively). In subgroup analyses by ethnicity, a significantly decreased risk was associated with -308 variant genotypes (GA and AA) in Mongoloid populations in all genetic models. However, no significant associations were found in Caucasoids. Moreover, in the subgroup analyses by control group, significantly decreased risk was associated with -308 variant genotypes (GA and AA) in the group of spontaneously recovered cases in all genetic models; however, no significant associations were found in the group of healthy cases.

CONCLUSIONS

The TNF-alpha-308A allele is a protective factor for chronic HBV infection, especially in Mongoloids.

Association study of IFNAR2 and IL10RB genes with the susceptibility and interferon response in HBV infection

A recent genome-wide association study discovered that two polymorphisms, interferon (IFN) alpha receptor 2 (IFNAR-2) F8S and interleukin 10 receptor (IL10RB) K47E, were associated with susceptibility to hepatitis B virus (HBV) infection in Africa. Here, we reevaluate the effects of the two polymorphisms on HBV susceptibility in the Chinese Han population, and extended the study to look at their association with IFN response in chronic hepatitis B (CHB). We included 341 patients with CHB and 341 unrelated controls presenting with asymptotic HBV self-limited infection, who were well matched in age and sex. In the CHB group, 101 patients had been treated with peg-IFN-alpha-2a for 48 weeks and followed up for 24 weeks to determine the clinical response, resulting 34 individuals with sustained virological response (SVR) and 67 individuals with nonsustained response (NR). Subgroups in the CHB group were divided according to the viral loads, HBeAg and maternal HBsAg status. The association with the susceptibility to HBV infection was only observed for IL10RB K47E when we compared the individuals with persistent HBV infection through nonmaternal transmission to the controls with asymptomatic self-limited HBV infection. Further, we found that the IFNAR2-8SS genotype was associated with HBeAg negative patients (OR = 0.316, 95% CI: 0.121-0.825, P = 0.019) and that the IFNAR2-8F allele was associated with the risk to high viral loads (OR = 1.667, 95% CI: 1.148-2.420, P = 0.007). In addition, the IFNAR2-8FF genotype predisposed to higher MxA gene induction and correlated with sustained IFN response (OR = 0.348, 95% CI: 0.129-0.935, P = 0.036). Haplotype analysis based on polymorphisms of three single-nucleotide polymorphisms, MxA - 88 G/T, IFNAR-2 F8S and IL10RB K47E showed that the haplotype distribution was significantly different between the SVR and NR groups (P = 0.040). This study suggests that IFNAR2 may play an important role in determining IFN response and clinical phenotypes of HBV infection in the Chinese Han population.

Association of interferon-gamma +874A polymorphism with the risk of developing cervical cancer in north-Indian population

OBJECTIVE

Interferon gamma (IFN-gamma) is a pro-inflammatory cytokine playing a pivotal role in both innate and adaptive immune responses. A single nucleotide polymorphism located in the first intron of the human IFN-gamma gene can influence the secretion of cytokine. Therefore, we aimed to investigate the association of IFN-gamma T/A gene polymorphism with the risk of cervical cancer.

DESIGN

Case-control study.

SETTING

Uttar Pradesh State in India.

SAMPLE

Two hundred cases with histologically proven cancer of the cervix and healthy controls (n = 230), age and ethnicity matched were recruited in this study.

METHODS

Genotyping was performed for bi-allelic +874 (T/A) polymorphism of IFN-gamma by amplification refractory mutation system method.

MAIN OUTCOME MEASURES

Low producer IFN-gamma +874 AA genotype was associated with high risk for cervical cancer, which further modulated the increased risk in tobacco users.

RESULTS

IFN-gamma AA genotype which is low producer of IFN-gamma was associated with increased risk of cervical cancer (OR = 2.43, P = 0.003). Allele A was at 1.54-fold increased risk of cervical cancer (OR=1.54, P = 0.002). The AA genotype showed statistically significant risk with high stage (III + IV) of cervical cancer (OR = 4.99, P = 0.001). In tobacco users, AA genotype showed significantly increased susceptibility to cervical cancer (OR = 5.08, P = 0.010).

CONCLUSION

Variation in IFN-gamma +874 AA genotype because of ethnicity in north-Indian population may represent an important susceptibility biomarker for cervical cancer risk as well as other diseases and should be explored further.

A regulatory polymorphism in interferon-gamma receptor 1 promoter is associated with the susceptibility to chronic hepatitis B virus infection

The antiviral cascade triggered by interferon-gamma (IFN-gamma) represents a vital event for eradicating hepatitis B virus (HBV) in experimental animals. IFN-gamma signaling is mediated through the ligand binding to IFN-gamma receptor 1 (IFNGR1). Control of IFNGR1 expression level is one of the mechanisms by which cells modulate the potency of IFN-gamma signaling. In this study, we comprehensively investigated the single nucleotide polymorphisms (SNPs) in IFNGR1 gene and correlated their occurrence to susceptibility to HBV infection in a Chinese population. A total of 983 participants, including 361 chronic hepatitis B patients, 256 individuals who had spontaneously recovered from HBV infection, and 366 healthy control subjects, were enrolled in the study. Polymerase chain reaction-restriction fragment length polymorphism was used to identify seven SNPs (-611A/G, -56C/T, 40G/A, 95C/T, 130A/G, 20685A/G, 21227T/C) in IFNGR1 gene. We found that -56C and -56T allele were associated with viral clearance and viral persistence, respectively (P = 0.014). In a reporter-driven assay, we validated that the promoter variant with -56C exhibited a higher transcription level than that with -56T in HepG2 cells in a cell-type-specific pattern. We conclude that a functional -56C/T SNP in IFNGR1 promoter is associated with the clinical outcome of HBV infection in this Chinese population.

Genetic polymorphisms in the cytokine genes and risk of hepatocellular carcinoma in low-risk non-Asians of USA

Polymorphisms in cytokine genes responsible for inflammatory and immune responses are associated with risk of hepatocellular carcinoma (HCC) in high-risk Chinese population. Similar data in low-risk populations are lacking. A population-based case-control study of HCC was conducted including 120 HCC patients and 230 matched control subjects of non-Asian residents in Los Angeles County, California. Genetic variants in the interferon gamma (IFNgamma), tumor necrosis factor-alpha (TNFalpha), interleukin-2 (IL-2), IL-4, IL-6, IL-10, IL-12 and IL-18 genes were determined by Taqman assays. The logistic regression method was used to analyze the data. For T helper (Th) 1 genes (IFNgamma, IL-6 and IL-12), relative to the putative high-activity genotypes, individual low-activity genotypes were associated with statistically non-significant increases in HCC risk. The odds ratio (OR) was 1.53 [95% confidence interval (CI) = 0.53-4.39] for three versus zero low-activity genotypes. For Th2 cytokines (IL-4 and IL-10), low- versus high-activity genotypes were associated with statistically non-significant decreases in HCC risk. The OR was 0.64 (95% CI = 0.27-1.55) for two versus zero low-activity genotypes. When the Th1 and Th2 genotypes were examined simultaneously, the highest level of risk was observed in individuals jointly possessing the highest number of low-activity Th1 genotypes and the lowest number of low-activity Th2 genotypes. There was a roughly doubling of risk between these two extreme genetic profiles, which did not reach statistical significance (OR = 1.98, 95% CI = 0.50-7.84, P = 0.08). In contrast to high-risk Chinese, Th1 and Th2 genotypes did not impact in a major way on risk of HCC in USA non-Asians.

A561C and G98T polymorphisms and plasma soluble levels of E-selectin in patients with chronic HBV infection

AIM: To investigate the association between A561C polymorphism in the exon 2 and the G98T polymorphism in the exon 4 of E-selectin gene and disease progression in a HBV-infected Chinese Han population, and also to determine the plasma soluble E-selectin levels in these people.

METHODS: Polymorphisms (Pst I for A561C and Hph I for G98T) of E-selectin gene were analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 367 HBV carriers and 281 healthy controls. The plasma soluble E-selectin levels were measured using specific enzyme-linked immunosorbent assay (ELISA).

RESULTS: There was significant difference in frequencies of A/C+C/C genotype and C allele in E-selectin A561C polymorphism between patients with liver cirrhosis (LC) and controls (P = 0.006 and P = 0.002). The relative risk of LC with A/C+C/C genotype was 2.45 times of those with A/A genotype (OR = 2.45, 95%CI: 1.28-4.72). There was no difference in genotype and allele distribution for E-selectin G98T polymorphism between each group and controls. But in patients with LC, the frequency of G/T+T/T genotype was of significant difference between Child' class A and class B plus C after the Child-Pugh classification (P = 0.034), the relative risk of Child-pugh B or C with G/T+T/T genotype was 3.07 times of those with G/G genotype (OR = 3.07, 95%CI: 1.05-8.97). Plasma levels of soluble E-selectin were significantly increased in HBV carriers with chronic hepatitis (CH) and LC compared with controls (P < 0.01). In the subgroup of LC, levels of soluble E-selectin were significantly decreased from Child' class A to class C (P < 0.05). In each group, people with C allele showed higher soluble E-selectin levels than those with A allele (P < 0.05).

CONCLUSION: E-selectin A561C polymorphism may be associated with liver cirrhosis in patients with chronic HBV infection and affect the plasma soluble levels, and the G98T polymorphism may be related to fibrotic severity.

A genome-wide association study identifies variants in the HLA-DP locus associated with chronic hepatitis B in Asians

Chronic hepatitis B is a serious infectious liver disease that often progresses to liver cirrhosis and hepatocellular carcinoma; however, clinical outcomes after viral exposure vary enormously among individuals. Through a two-stage genome-wide association study using 786 Japanese chronic hepatitis B cases and 2,201 controls, we identified a significant association of chronic hepatitis B with 11 SNPs in a region including HLA-DPA1 and HLA-DPB1. We validated these associations by genotyping two SNPs from the region in three additional Japanese and Thai cohorts consisting of 1,300 cases and 2,100 controls (combined P = 6.34 x 10(-39) and 2.31 x 10(-38), OR = 0.57 and 0.56, respectively). Subsequent analyses revealed risk haplotypes (HLA-DPA1(*)0202-DPB1(*)0501 and HLA-DPA1(*)0202-DPB1(*)0301, OR = 1.45 and 2.31, respectively) and protective haplotypes (HLA-DPA1(*)0103-DPB1(*)0402 and HLA-DPA1(*)0103-DPB1(*)0401, OR = 0.52 and 0.57, respectively). Our findings show that genetic variants in the HLA-DP locus are strongly associated with risk of persistent infection with hepatitis B virus.

Systematic -omics analysis of HBV-associated liver diseases

Hepatitis B virus (HBV) infection causes acute and chronic liver diseases and increases the risk of developing hepatocellular carcinoma (HCC). However, the pathogenesis of HBV infection and carcinogenesis of HBV-associated HCC are still elusive. In this review, systematic -omics studies made in the scales of genomics, transcriptomics and proteomics were discussed. The susceptibility to HBV infection and the course of disease progress are greatly different among individuals. Using population- or/and family-based approaches, relevant genes have been mapped or identified to be associated with host immune responses to HBV antigens and susceptibility to HCC. Comprehensive transcriptomic analyses have shown that the HBV-induced hepatocarcinogenesis may involve the whole course from signal transduction, transcription, translation to protein degradation, which differs in some measure from HCV-induced hepatocarcinogenesis, and that exogenous transcription factor HBX and endogenous NF-kappaB are likely two key points of the course. By the means of proteomics, dozens of important dysregulated proteins (including isoforms or fragments) were identified from carcinogenesis mechanism analysis and biomarker validation. Of them, the alteration of heat shock proteins and impairment of methylation cycle were found to be associated with clinical HBV-associated HCC. As a whole, the systematic -omics analysis of HBV-associated liver diseases has offered multi-scale pathological information in the process from HBV infection to HCC onset.

Polymorphisms of microsomal triglyceride transfer protein in different hepatitis B virus-infected patients

AIM: To identify the two polymorphisms of microsomal triglyceride transfer protein (MTP) gene in the Chinese population and to explore their correlation with both hepatitis B virus (HBV) self-limited infection and persistent infection.

METHODS: A total of 316 subjects with self-limited HBV infection and 316 patients with persistent HBV infection (195 subjects without familial history), matched with age and sex, from the Chinese Han population were enrolled in this study. Polymorphisms of MTP at the promoter region -493 and at H297Q were determined by the allele specific polymerase chain reaction (PCR).

RESULTS: The ratio of males to females was 2.13:1 for each group and the average age in the self-limited and chronic infection groups was 38.36 and 38.28 years, respectively. None of the allelic distributions deviated significantly from that predicted by the Hardy-Weinberg equilibrium. There was a linkage disequilibrium between H297Q and -493G/T (D’ = 0.77). As the χ² test was used, the genotype distribution of MTP-493G/T demonstrated a significant difference between the self-limited infection group and the entire chronic group or the chronic patients with no family history (χ² = 8.543, P = 0.015 and χ² = 7.199, P = 0.019). The allele distribution at the MTP-493 position also demonstrated a significant difference between the study groups without family history (χ² = 6.212, P = 0.013). The T allele emerged as a possible protective factor which may influence the outcomes of HBV infection (OR: 0.59; 95% CI: 0.389-0.897).

CONCLUSION: The polymorphism of the MTP gene, T allele at -493, may be involved in determining the HBV infection outcomes, of which the mechanism needs to be further investigated.

Association of cytokine gene polymorphisms and liver fibrosis in chronic hepatitis B

BACKGROUND AND AIM

As liver fibrosis is the result of persistent necroinflammation in the liver, pro-inflammatory cytokines secreted in response to cell injury have a central role in the pathogenesis of liver fibrosis. We aimed to investigate the association of cytokine gene polymorphism and liver fibrosis among Chinese patients with chronic hepatitis B.

METHODS

Polymorphisms at interleukin-10 (IL-10-627, -1117), interleukin-1-beta (IL-1beta-511, -31, -3964), interleukin-1 receptor antagonist (IL-1RN), and tumor necrosis factor-alpha (TNF-alpha-308, -238) among Chinese chronic hepatitis B patients were determined. Severe liver fibrosis was defined as Ishak fibrosis score = 4 (of 6).

RESULTS

Fifty-nine of 273 (22%) patients had severe fibrosis. The distribution of genotypes for IL-10-627 was CC (11%), CA (41%), and AA (48%). The CC genotype at IL-10-627 was protective against severe fibrosis (odds ratio (OR) 0.11; 95% CI 0.014-0.82; P = 0.032). After adjusted for baseline variables, the adjusted OR of CC genotypes at IL-10-627 for severe fibrosis was 0.063 (95% CI 0.06-0.64; P = 0.063). Other gene polymorphisms at IL-1beta, IL-1RN, TNF-alpha, and IL-10 had no significant association with severe fibrosis. Weak linkage disequilibrium was observed between IL-10-627 and IL-10-1117 with linkage disequilibrium coefficient of 0.12 (P < 0.001). The distribution of haplotypes of IL-10-1117 and IL-10-627 was A-A (69%), A-C (26%), and G-C (5%). High and intermediate IL-10 production (A-C and G-C) haplotypes were protective against severe fibrosis (OR 0.62; 95% CI 0.39-0.99; P = 0.046).

CONCLUSIONS

High production genotype and haplotypes of IL-10 were associated with less severe liver fibrosis in chronic hepatitis B in Chinese.

Association of TGF-beta1 codon 25 (G915C) polymorphism with hepatitis C virus infection

Cytokines play a key role in the regulation of immune responses. In hepatitis C virus infection (HCV), the production of abnormal cytokine levels appears to contribute to the progression of the disease, viral persistence, and affects response to therapy. Cytokine genes are polymorphic at specific sites, and certain polymorphisms located within coding/regulatory regions have been shown to affect the overall expression and secretion of cytokines. The aim of the present study was to identify potential markers of cytokines genes associated with the susceptibility to HCV infection. The cohort was composed of 128 individuals infected by HCV and 94 healthy controls. Genotyping was carried out by PCR-SSP. The distributions of the following polymorphisms were compared in these groups: TNF-alpha (-308G/A [rs1800629]), TGF-beta1 (codon 10 T/C [rs1982073], codon 25 G/C [rs1800471]), IL-10 (-1082 A/G [rs 1800896]; -819T/C [rs1800871]; -592A/C [rs 1800872]), IL-6 (-174G/C [rs1800795]), and IFN-gamma (+874T/A [rs2430561]). This study demonstrated a statistically significant difference in the frequency of TGF-beta1 codon 25 polymorphism between healthy subjects and those infected with HCV. No associations were observed between polymorphisms of TNF-alpha, IFN-gamma, IL-10, TGF-beta1 codon 10, and IL-6 and HCV infection. These findings suggest that TGF-beta1 codon 25 polymorphism could be a host genetic factor associated with susceptibility to HCV infection.

Matrix metalloproteinase-3 genotypes influence recovery from hepatitis B virus infection

The reasons for the viral persistence of hepatitis B virus (HBV) infection are unknown, but are probably related to host immune factors. Several matrix metalloproteinases (MMPs) can regulate an inflammatory response. The aim of this study was to assess the effects of the single nucleotide polymorphisms (SNPs) of MMP-3 and -9 genes on the susceptibility to persistent HBV infection. We studied 489 Korean patients with HBV infection (144 inactive carriers, 182 chronic hepatitis, and 163 liver cirrhosis) and 174 healthy individuals who had recovered from HBV infection. MMP-3 gene SNPs were identified at two polymorphic sites (codon 45 [E45K] and codon 96 [D96D]) and MMP-9 gene SNPs at three polymorphic sites (codon 279 [R279Q], codon 607 [G607G], and codon 668 [Q668R]) in study subjects. The frequency of T allele at third position of codon 96 in the MMP-3 gene was higher in HBV persistence patients when analyzed by co-dominant model (age- and sex-adjusted OR=1.242, 95% CI= 1.001-1.540, p=0.049). In conclusion the T allele at the third position of codon 96 in the MMP-3 gene might be associated with persistent HBV infection.

Use of tumor necrosis factor-alpha inhibitors in patients with chronic hepatitis B infection

OBJECTIVE

Tumor necrosis factor-alpha (TNF-alpha) inhibitors have emerged as a potent treatment for rheumatoid arthritis (RA), but not without significant risks. In chronic hepatitis B viral infection TNF-alpha is readily produced, and viral clearance is dependent on the amount bioavailable. Limited data suggest that TNF-alpha inhibitors may facilitate uncontrolled hepatitis B viral replication. The purpose of this article was to provide a detailed review of the role of TNF-alpha in controlling hepatitis B viral infection and the clinical impact blockade might have on viral control.

METHODS

We describe a patient with chronic hepatitis B viral infection and RA treated with etanercept. We then review case reports, expert opinion, and manufacturer recommendations regarding hepatitis B viral infection, TNF-alpha, and TNF-alpha inhibitors.

RESULTS

To date, 13 patients with chronic hepatitis B infection treated with TNF-alpha inhibitors have been reported: 11 with infliximab and 2 with etanercept. Some patients received antiviral therapy for hepatitis B (specifically lamivudine) before, during, or after TNF-alpha inhibitors were started. Clinically apparent reactivation of hepatitis B virus typically occurred 1 month after the 3rd dose of infliximab. Etanercept was not associated with a similar reactivation. The difference between infliximab and etanercept in viral reactivation may be linked to the pharmacologic difference of each medication.

CONCLUSIONS

TNF-alpha inhibitors in general should be used cautiously in chronic hepatitis B viral infection. But if necessary, when deciding which agent to use, the clinician should consider the mechanism by which the body clears TNF-alpha.

Association of cytokine genetic polymorphism with hepatitis B infection evolution in adult patients

The infection by the hepatitis B virus (HBV) has different forms of evolution, ranging from self-limited infection to chronic hepatic disease. The objective of this study was to evaluate the influence of cytokine genetic polymorphisms in the disease evolution. The patients were divided into two groups, one with chronic HBV (n = 30), and the other with self-limited infection (n = 41). The genotyping for TNF (-308), TGFB1 (+869, +915), IL-10 (1082, -819, and -592), IL-6 (-174), and IFNG (+874) was accomplished by the PCR-SSP (polymerase chain reaction with sequence specific primers technique using the One Lambda kit. Although no statistically significant differences were found between the groups, the combination of TNF -308GG and IFNG +874TA was found in a lower frequency in chronic patients than in individuals with self-limited infection (26.7 versus 46.3%; P = 0.079; OR = 0.40; IC95% = 0.14-1.11). In chronic patients with histological alterations it was not observed the genotype TGFB1+869 C/C, against 24.4% in the self limited infection group (100 versus 75.6%; P = 0.096; OR = 7.67; IC95% = 0.42-141.63). Further studies in other populations, and evaluation of a greater number of individuals could contribute for a better understanding of the cytokine genetic polymorphism influence in HBV infection evolution.

Influences of MxA gene -88 G/T and IFN-gamma +874 A/T on the natural history of hepatitis B virus infection in an endemic area

The influence of human genetics on the natural history of hepatitis B virus (HBV) infection may be diminished in endemic areas because infection at a young age predisposes to chronic HBV infection. The present study aimed to address this issue through the determination of the influences of single nucleotide polymorphisms (SNPs) of myxovirus resistence-1 (MxA) -88 G/T and interferon (IFN)-gamma +874 A/T on the natural history of HBV infection in endemic regions. One hundred adult patients with self-limiting HBV infection (positive for both anti-HBs and anti-HBc) and 340 adult patients with persistent HBV infection were recruited from southern China, an endemic area with an HBsAg carrier rate of 17.8%. SNPs of MxA -88 G/T and interferon (IFN)-gamma +874 A/T were typed using a protocol based on competitively differentiated polymerase chain reaction. A highly significant difference in the distribution of MxA -88 G/T was observed between those with persistent and self-limiting HBV infections. The latter displayed a lower frequency of the GG genotype (41.0% vs. 52.9%, P = 0.036) and a higher frequency of the TT genotype (16.0% vs. 2.4%, P = 0.000), compared to patients with persistent infection. These differences were not gender- or age-specific. However, a significant distribution difference of IFN-gamma +874 A/T was not observed. Between two groups of patients, respectively, the distribution frequencies of the AA genotype (65.0% vs. 72.8%, P = 0.139) and the TT genotype (2.0% vs. 1.2%, P = 0.894) were found. These results suggest that MxA gene -88 G/T and IFN-gamma +874 A/T behave differently in endemic HBV infections. Further study is necessary to clarify the influences of human genetics on endemic HBV infections.

Single nucleotide polymorphisms and functional analysis of class II transactivator (CIITA) promoter IV in persistent HBV infection

BACKGROUND/AIMS

CIITA plays a pivotal role in immune response, and the outcome of HBV infection is influenced by immune response. The aims of this study were to analyze the effect of CIITA promoter IV polymorphisms on its activity, and their association with persistent HBV infection.

METHODS

The polymorphisms in promoter IV (C-1350T and G-944C) were analyzed by tetra-primer amplification refractory mutation system polymerase chain reaction (ARMS-PCR), and four haplotypes were assigned in 1420 HBV infected subjects. The functional analysis on haplotypes of promoter IV was studied using pGL3-basic and pGL3-promoter vectors.

RESULTS

There were significantly decreased-TG and increased-CC haplotype frequencies in persistent HBV infected subjects (34.8% and 41.3%), compared with spontaneously recovered subjects (46.5% and 36.2%). There were significantly higher CC/CC and lower TG/TG genotype frequencies in persistent infected subjects (20.3% and 11.1%) than in spontaneously recovered subjects (10.9% and 23.1%). The mean relative luciferase activity of promoter IV were the highest in TG haplotype (0.558+/-0.023), and the lowest in CC haplotype (0.302+/-0.016).

CONCLUSIONS

The polymorphisms of CIITA promoter IV are associated with persistent HBV infection. The CC haplotype with the lowest activity of promoter and CC/CC genotype are responsible for persistent HBV infection.

Association of HLA-DRB1*13 and TNF-alpha gene polymorphisms with clearance of chronic hepatitis B infection and risk of hepatocellular carcinoma in Thai population

Considerable evidence suggests that host genetic factor play an important role in the pathogenesis and clinical outcome of chronic hepatitis B virus (HBV) infection in several ethic groups. Association study was performed included 150 chronic HBV patients, 100 resolved hepatitis B and 150 healthy individuals with similar ethic background. Interestingly, human leucocyte antigen (HLA)-DR13 show a strong association with the clearance of HBV [odds ratio (OR) = 0.04, 95% confidence interval (CI) = 0.00-0.26, corrected P-value (P(c)) = 0.0008] similar to reports from several ethic groups. TNF-alpha promoter polymorphisms (-863, -308 and -238) were also analysed. Only -863 C allele was found to be significantly decreased in chronic HBV patients compared with healthy control (P(c) = 0.03, OR = 0.54, 95% CI = 0.35-0.84 respectively). This -863C allele was not in linkage disequilibrium with HLA-DR13 suggesting that other genetic markers linked with -863C might influence clearance of chronic HBV infection in Thai. When stratified chronic HBV patients into patients without hepatocellular carcinoma (HCC) and with HCC, the -863 A allele was significantly increased in the HCC group compared to healthy control (P(c) = 0.003, OR = 2.61, 95% CI = 1.49-4.60). Haplotype analysis (-863/-308/-238) revealed that the homozygosity of the haplotype (CGG/CGG) was a protective marker for HCC (OR = 0.37, 95% CI = 0.17-0.79, P(c) = 0.02). One can propose that carriers of -863A genotype are associated with increased levels of TNF-alpha in the liver in response to HBV infection and induce hapatocyte damage that may finally lead to HCC development. Additional study is needed to validate these finding and to further explore the genetic pathogenesis of HBV infection.

Association of TNF-alpha -308 polymorphism with the outcome of hepatitis B virus infection in Turkey

BACKGROUND AND AIM

Cytokines play important roles in the regulation of immune response. The aim of the study was to investigate the association of the cytokine gene polymorphisms with persistence of hepatitis B virus (HBV) infection and the development of end-stage liver disease (ESLD) due to HBV infection.

METHODS

The study involved 27 patients with end-stage liver disease due to HBV infection, 23 HBV carriers and 60 healthy controls. All genotyping (TNF-alpha, TGF-beta, IL-10, IFN-gamma) experiments were performed using sequence specific primers (PCR-SSP) by using commercial kit according to manufacturers' instructions.

RESULTS

The frequencies of TNF-alpha -308 G/G and TGF-beta1 codon 10-25 T/C-G/G polymorphisms were significantly higher in HBV-infected individuals (patients+carriers) when compared with those of healthy controls (p: 0.02 and p: 0.004, respectively). The frequency of TNF-alpha -308 G/G polymorphism was significantly higher in the patients than those of the healthy controls (p: 0.02), whereas the frequency of TGF-beta1 codon 10-25 T/T-G/G polymorphism was lower (p: 0.028). On the other hand, TNF-alpha -308 G/G and TGF-beta codon 10-25 T/C-G/G polymorphisms were significantly more common in HBV carriers than the control group (p: 0.017 and p: 0.018, respectively). In addition, TNF-alpha -308 G allele frequency was significantly more common in HBV-infected individuals (patients+carriers) than those of healthy controls (p: 0.0007). TNF-alpha -308 G allele frequency was also found to be higher in patients or carriers when compared with those of healthy controls (p: 0.01 and p: 0.01, respectively). Statistically significant differences were still kept after Bonferroni correction of the p-values for only TNF-alpha -308 G allele frequency in patients or carriers (Pc).

CONCLUSION

Our study suggests that TNF-alpha gene polymorphism in patients infected with HBV would result in relatively inefficient inhibition of HBV and development of ESLD, and therefore, may be valuable predictor determinants for the development of ESLD in patients with chronic HBV infection.

Cytokine gene polymorphisms in acquired bone marrow failure

Some acquired aplastic anemia (AA) results from immune-mediated destruction of hematopoietic stem cells. Cytokine gene polymorphisms are implicated in controlling cytokine production and increasing the susceptibility to some autoimmune diseases. We characterized the IL-6/-174, TNF-alpha/-308, IL-10/-1082, IFN-gamma/+874, TGFbeta1/-509 single nucleotide polymorphisms (SNP's) and the IL1-RA second intron variable number tandem repeat (VNTR) alleles in 73 patients with AA and compared the frequency of genotypes to established control populations. We found that some patients with acquired AA have polymorphisms which are linked to high production of proinflammatory cytokines, particularly TNF-alpha and IFN-gamma.

RANTES, MCP-1, CCR2, CCR5, CXCR1 and CXCR4 gene polymorphisms are not associated with the outcome of hepatitis B virus infection: results from a large scale single ethnic population

Recovery from hepatitis B virus (HBV) infection depends on the cellular immune responses. Chemokines and their receptors play significant roles in immune defense. This study was undertaken to investigate the association between HBV infection and single nucleotide polymorphisms (SNPs) of genes for the chemokines and their receptors. Between March 2002 and February 2004, a total of 957 single ethnic Korean patients were enrolled into two different groups; "HBV clearance group" (n=350), who have recovered from HBV infection, and "HBV persistence group" (n=607), who were repeatedly HBsAg-positive. The HBV persistence group was subdivided into "inactive carrier" and "HBV progression group (chronic hepatitis and cirrhosis)". We assessed polymorphisms in regulated and normal T-cell expressed and secreted (RANTES) at position -403, monocyte chemoattractant protein-1 (MCP-1) at position -2518, CCR2 V64I, CCR5 -2459, CXCR1 S276T and CXCR4 I138I using single primer extension assay. Genotype distributions of the "HBV clearance versus persistence group" and "inactive carrier versus HBV progression group" were compared. On the basis of unconditional logistic regression analysis with adjustment for age and sex, no statistically significant association with susceptibility to persistent HBV infection was observed with RANTES -403, MCP-1 -2518, CCR2 V64I, CCR5 -2459, CXCR1 S276T, and CXCR4 I138I polymorphisms. In addition, no association of analyzed SNPs with HBV disease progression was found.

Advance in genetic factors influencing hepatitis B virus infection

Hepatitis B virus (HBV) infection is a major global health problem. A complex combination of environment and virus, especially host genetic factors, play a critical role in determining both susceptibility to HBV persistence and different clinical outcomes after HBV infection. In this review, we summarized the main relevant genes such as human leukocyte antigen (HLA), tumor necrosis factor (TNF), interleukins (ILs), interferons (IFNs), etc. However, in order to identify all the relevant polymorphisms that affect the outcome of HBV infection, alternative strategies such as genome-wide association studies with large sample sizes are required to define the majority of the related genes.

A comparative review of HLA associations with hepatitis B and C viral infections across global populations

Hepatitis B (HBV) and hepatitis C (HCV) viral infection or co-infection leads to risk of development of chronic infection, cirrhosis and hepatocellular carcinoma (HCC). Immigration and globalization have added to the challenges of public health concerns regarding chronic HBV and HCV infections worldwide. The aim of this study is to review existing global literature across ethnic populations on HBV and HCV related human leukocyte antigen (HLA) associations in relation to susceptibility, viral persistence and treatment. Extensive literature search was conducted to explore the HLA associations in HBV and HCV infections reported across global populations over the past decade to understand the knowledge status, weaknesses and strengths of this information in different ethnic populations. HLA DR13 is consistently associated with HBV clearance globally. HLADRB1*11/*12 alleles and DQB1*0301 are associated with HBV persistence but with HCV clearance worldwide. Consistent association of DRB1*03 and *07 is observed with HCV susceptibility and non-responsiveness to HBV vaccination across the population. HLA DR13 is protective for vertical HBV and HCV transmission in Chinese and Italian neonates, but different alleles are associated with their susceptibility in these populations. HLA class I molecule interactions with Killer cell immunoglobulin like receptors (KIR) of natural killer (NK) cells modulate HCV infection outcome via regulating immune regulatory cells and molecules. HLA associations with HBV vaccination, interferon therapy in HBV and HCV, and with extra hepatic manifestations of viral hepatitis are also discussed. Systematic studies in compliance with global regulatory standards are required to identify the HLA specific viral epitope, stage specific T cell populations interacting with different HLA alleles during disease progression and viral clearance of chronic HBV or HCV infections among different ethnic populations. These studies would facilitate stage specific therapeutic strategies for clearance of HBV and HCV infections or co-infections across global populations and aid in identification of HBV-HCV combined vaccine. HLA associations of chronic HBV or HCV development with confounding host factors including alcohol, drug abuse, insulin resistance, age and gender are lacking and warrant detailed investigation across global populations.

Polymorphisms of type I interferon receptor 1 promoter and their effects on chronic hepatitis B virus infection

BACKGROUND/AIMS

Exposure to HBV leads to a distinct clinical course which is partially pertained to host genetic variability. We aimed to study polymorphisms of type I interferon receptor 1 (IFNAR1) promoter and their potential effects on chronic HBV infection.

METHODS

Polymorphisms of IFNAR1 promoter were identified in 320 chronic hepatitis B patients, 148 spontaneously recovered individuals, 148 healthy Chinese donors and 114 Caucasians. Their functional capability in driving reporter gene expression was analyzed.

RESULTS

Four polymorphic alleles were identified at loci -568, -408, -77 and -3. Association analysis revealed that carriers of alleles -568G, -408C and their related haplotype I were less susceptible to chronic HBV infection whereas those of alleles -568C, -408T and related haplotype III were significantly associated with higher risk to chronic hepatitis B (P<0.01). In a reporter-driven system, the promoter variants with alleles -408C and -3C could drive higher expression of the reporter gene than those with alleles -408T and -3T (P<0.01). Interestingly, an allele with 9 GT repeats at -77 that was rarely found in Chinese but prevalent in Caucasian exhibited the highest transcriptional ability.

CONCLUSIONS

Our results showed that polymorphisms of IFNAR1 promoter may affect, at least in part, the outcomes of HBV infection.

Serum neopterin levels in patients with replicative and nonreplicative HBV carriers

Background

Infection by hepatitis B virus (HBV) causes complicated biochemical, immunological and histological changes in host immune response against the virus which can be specific or non-specific. Recent attention has focused on neopterin as a marker for the activation of cell mediated immunity. The aim of this study was to define the pattern of neopterin levels in replicative and nonreplicative HBV carriers.

Methods

Thirty HBV replicative carriers and 25 nonreplicative HBV carriers and 30 healthy adult patients were included this study. Hepatitis markers were determined by commercial kit based on chemilumminesans assay. HBV DNA was quantified by hybrid capture system. Serum neopterin levels were measured by the method of competitive enzyme-linked immunosorbent assay. Results were expressed as mean ± SD and ranges.

Results

In the nonreplicative group, except for one patient, all the patients' HBeAg were negative and anti-HBe were positive. That particular patient was HBeAg positive and anti-HBe negative. In the replicative group, 23 out of 30 patients have positive HBeAg and negative anti-HBe; 7 out of 30 patients have negative HBeAg and positive anti-HBe. Serum neopterin concentrations were 14.5 ± 10.0 (4.2–41) nmol/L in replicative HBV carriers, 8.9 ± 4.3 (2.1–22) nmol/L in nonreplicative HBV carriers and 7.1 ± 2.2 (4.0–12) nmol/L in the control group. Serum neopterin levels and the rates of abnormal serum neopterin levels in the replicative group were higher than the control group (P < 0.01 and P < 0.05). In the nonreplicative group, serum neopterin levels were not different from those of the control. There was a difference between replicative and nonreplicative groups in the respect of neopterin levels.

Conclusion

In the hepatitis B infected carriers, elevated neopterin levels may be an indicator of the presence of replication.

Association of interferon-gamma gene haplotype in the Chinese population with hepatitis B virus infection

In general, cytokines encoded by different genes of human genome might strongly influence host cell-mediated immune responses, which play an important role in the clearance of virus by the infected host. Interferon gamma (IFN-gamma) produced by T lymphocytes and natural killer cells plays an essential role in affecting cellular immune responses. A functional study demonstrated that two single nucleotide polymorphisms located in the IFN-gamma gene intron (at positions +874 and +2109) were involved in its transcriptional regulation. The aim of this study was to evaluate whether IFN-gamma gene polymorphisms or its haplotypes might be associated with predisposition to hepatitis B virus (HBV) infection in the Chinese population. The study included 181 cases with HBV infection and 272 gender, age-matched healthy controls. All genotyping were identified by polymerase chain reaction in association with the measurement of amplification refractory mutation system. A significant difference was observed between case and control groups. The frequency of +874A allele was significantly higher in patients than in controls (OR = 2.25, 95%CI = 1.69-2.99, P < 0.0001). However, no significant difference was found in the allelic frequencies of IFN-gamma +2109A/G between cases and controls (P > 0.05). By haplotype analysis, the frequency of haplotype AG (+874A and +2109G) revealed a significant difference in the cases in comparison to controls (P < 0.0001). Multiple logistic regression analysis showed that individuals possessing haplotype AG had an increased likelihood of HBV infection (OR = 8.14, 95%CI = 4.98-13.30). Our results suggest that haplotype AG containing +874A and +2109G may be a crucial risk factor of genetic susceptibility to HBV infection in the Chinese population.

A promoter polymorphism in the interferon alpha-2 gene is associated with the clinical presentation of hepatitis B

Cytokine gene polymorphisms influence the severity of infectious diseases of viral and parasitic origin. Interferon alpha (IFN-alpha) is known to be involved in the defence against hepatitis B. The promoter of the IFN-alpha-2 gene was investigated for mutations in 344 hepatitis B virus (HBV)-infected Vietnamese patients and 293 uninfected Vietnamese. We found a deletion in the promoter, which was present significantly more frequently in HBV-infected patients than in control individuals; 20% of the healthy, whereas 35% of the HBV-infected cohort carries this deletion (P<0.001). Reporter gene assays showed that a construct with the deletion had a lower level of transcription in comparison to the wild type (P=0.011). These findings indicate that the deletion in the promoter of the IFN-alpha-2 gene reduces the transcription of this gene in vitro. This reduction could explain the individually different interferon levels in humans and could also be one cause of susceptibility to hepatitis B.

The role of cytokines in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a frequent malignancy worldwide with a high rate of metastasis. The hepatitis B and C viruses are considered major etiological factors associated with the development of HCC, particularly as a result of their induction of chronic inflammation. There is increasing evidence that the inflammatory process is inherently associated with many different cancer types, including HCC. Specifically, this review aims to cover evidence for the potential roles of cytokines, an important component of the immune system, in promoting HCC carcinogenesis and progression. A global summary of cytokine levels, functions, polymorphisms, and therapies with regard to HCC is presented. In particular, the role of proinflammatory Th1 and anti-inflammatory Th2 cytokine imbalances in the microenvironment of HCC patients with metastasis and the possible clinical significance of these findings are addressed. Overall, multiple studies, spanning many decades, have begun to elucidate the important role of cytokines in HCC.

Cytokine gene polymorphisms can alter the effect of Bacillus Calmette-Guérin (BCG) immunotherapy

Various types of cancer are more frequent in men than women, and bladder cancer is one of the most common of these. Intravesical instillation of Bacillus Calmette-Guérin (BCG) after transurethral resection is the most effective treatment for superficial bladder cancers. The main aim of this study was to investigate for possible links between cytokine gene polymorphisms and different outcomes after BCG immunotherapy. Sixty patients who had been diagnosed with transitional cell cancer were investigated. All genotyping experiments were performed using polymerase chain reaction sequence-specific primers and a commercially available kit. The genes investigated were those that code for interleukin (IL)-1alpha, IL-1beta, IL-1R, IL-1RA, IL-4RA, IL-2, IL-4, IL-6, IL-10, IL-12, interferon-gamma (IFN-gamma), transforming growth factor-beta (TGF-beta), and tumor necrosis factor-alpha (TNF-alpha). Analyses of the data identified TGF-beta codon 25 GG (92.85% vs. 64.44%, p=0.04, OR=7.17), IL-4 -1098 GG (16.6% vs. 0.0%, p=0.05, OR=18.33), IL-10 -1082 GG (28.5% vs. 6.8%, p=0.05, OR=5.47), and IL-10 -1082 GCC/GCC (28.57% vs. 4.5%, p=0.025, OR=8.4) polymorphisms as risk factors for progression of bladder cancer.

Polymorphisms of interleukin-1R receptor antagonist genes in patients with chronic hepatitis B in Iran

AIM: To investigate the relationships between polymorphisms of interleukin-1R receptor antagonist genes and susceptibility to chronic hepatitis B in Iran population.

METHODS: Genomic DNA was extracted from the peripheral blood of 80 patients with chronic hepatitis B (57 males, 23 females) aged 12-77 years (mean 36.1 ± 13.8 years) and 147 normal controls (96 males, 51 females) aged 6-75 years (mean 41 ± 18.7 years) who referred to a liver clinic of Tehran and then subjected to polymerase chain reaction (PCR) amplification. PCR products were resolved on a 3% agarose gel and stained with ethidium bromide.

RESULTS: Only three of the five kinds of polymorphism (2/2, 2/4, and 4/4) were found in this study. The frequencies of 2/2, 2/4, and 4/4 were 12.5%, 17.5%, 70% respectively in chronic hepatitis B patients and 6.8%, 24.5%, and 68.7% respectively in controls. IL-1 R allele 2 was detected in 30% of chronic hepatitis B patients and in 31.3% of controls, while IL-1 R allele 4 was detected in 87.5% of chronic hepatitis B patients and in 93.2% of controls. The frequency of IL-1R alleles 2 and 4 was detected in 21.25% and 78.75% of the patients and 19.04% and 80.96% of the controls, respectively.

CONCLUSION: Our results suggest that the carriage of IL-1R receptor antagonist alleles 2, 4, 6 may not play any role in the development of HBV infection. Large population-based studies are needed to investigate the role of IL-1 polymorphisms in the pathogenesis of developing chronic hepatitis B.