Genetic association of human leukocyte antigens with chronicity or resolution of hepatitis B infection in thai population

Genome-Wide Association Study for Chronic Hepatitis B Infection in the Thai Population

To identify novel host genetic variants that predispose to hepatitis B virus (HBV) persistence, we performed the first genome-wide association study in the Thai population involving 318 cases of chronic hepatitis B and 309 healthy controls after quality control measures. We detected the genome-wide significant association of the HLA class II region (HLA-DPA1/DPB1, rs7770370, p-value = 7.71 × 10⁻¹⁰, OR = 0.49) with HBV chronicity. Subsequent HLA allele imputation revealed HLA-DPA1*01:03 (Pc = 1.21 × 10⁻⁶, OR = 0.53), HLA-DPB1*02:01 (Pc = 2.17 × 10⁻³, OR = 0.50), and HLA-DQB1*06:09 (Pc = 2.17 × 10⁻², OR = 0.07) as protective alleles, and HLA-DPA1*02:02 (Pc = 6.32 × 10⁻⁵, OR = 1.63), HLA-DPB1*05:01 (Pc = 1.13 × 10⁻⁴, OR = 1.72), HLA-DPB1*13:01 (Pc = 4.68 × 10⁻², OR = 1.60), and HLA-DQB1*03:03 (Pc = 1.11 × 10⁻³, OR = 1.84) as risk alleles for HBV persistence. We also detected suggestive associations in the PLSCR1 (rs35766154), PDLIM5 (rs62321986), SGPL1 (rs144998273), and MGST1 (rs1828682) loci. Among single-nucleotide polymorphisms in the PLSCR1 locus, rs1061307 was identified as the primary functional variant by in silico/in vitro functional analysis. In addition to replicating the association of the HLA class II region, we detected novel candidate loci that provide new insights into the pathophysiology of chronic hepatitis B.

Genetic polymorphisms of the HLA-DP and HLA-DQ genes could influence Hepatitis B virus infection in Yunnan population

Hepatitis B, caused by hepatitis B virus (HBV) infection, is one of the epidemic and infectious hepatitis diseases. The sigle-nucleotide polymorphisms were identified to associate with HBV infection in East Asian population by genome-wide association study (GWAS), but no study in Yunnan HBV population was reported. We recruited 493 HBV patients and 460 general controls to genotype 7 GWAS SNPs, and then, the association study was performed between these SNPs and biochemical features of HBV patients. The results showed that genotype and allele frequencies of SNPs in the HLA-DP (rs3077, 9277535, and 3128917) and HLA-DQ (rs2856718 and 7453920) genes were associated with HBV infection. Significantly different genotyping frequencies were investigated among three HBV subgroups. Genotype AA of rs3130542 (HLA-C) showed significantly higher frequency in subgroup #1 patients than the other two subgroups (#1 vs. #2, p = .02; #1 vs. #3, p = .03). Meanwhile, genotype frequencies of rs3077, rs9277535, and 3128917 (HLA-DP) were significantly different between patients in subgroup #2 and #3. The indirect bilirubin level was significantly lower in patients with genotype CT of rs3077 than patients with genotype CC (p = .009) or TT (p = .016), and it also showed lower level in patients with genotype GT of rs3128917 than patients with genotype GG (p = .015). The direct bilirubin level was higher in patients with genotype TT of rs4821116 (UBE2L3) than patients with genotype CT (p = .010). In summary, we identified the association between GWAS SNPs and HBV infection or biochemical features in Yunnan HBV population.

Assessment of HLADP gene rs3128917 and rs9380343 polymorphisms in chronic HBV infection

BACKGROUND/AIMS

About 400 million people worldwide have been exposed to Hepatitis B (HBV) infection. A range of 10%-15% of chronic HBV carriers may present with various liver diseases including cirrhosis and hepatic cancer. The chronicity or clearance of HBV infection is dependent on viral and genetic variables. Genome-wide association studies (GWAS) have reported that the variants of human leukocyte antigen (HLA), rs3128917 and rs9380343, are significantly related to persistent HBV infection. HLA molecules are responsible for introducing various antigens into the immune system. These variants might affect antigen presentation by influencing HLA mRNA expression, therefore, antigen presentation may not be performed properly. This study aims to assess the relationship of HLA gene variants to chronic HBV infection.

MATERIALS AND METHODS

HLA variants were explored in 238 chronic HBV patients and in 238 individuals with spontaneous clearance of HBV using PCR-RFLP assay.

RESULTS

The allele and genotype of rs9380343 polymorphism were associated with persistent HBV infection risk (allele: p=0.038, genotype: p=0.029), but rs3128917 polymorphism was not significant. Additionally, rs9380343 polymorphism was also related to increased risk of HBV infection in males (p<0.05).

CONCLUSION

The current study is the first report demonstrating the HLA rs9380343 polymorphism as a genetic risk factor for chronicity of HBV infection. Further independent studies are required to confirm the current findings using a larger sample size in different populations.

Circulating tumor DNA/circulating tumor cells and the applicability in different causes induced hepatocellular carcinoma

In 2015, liquid biopsy was rated one of the top 10 breakthrough technologies of the year by MIT Technology Review. Liquid biopsy is a type of in vitro diagnostic method involving a noninvasive blood test. It is also a breakthrough technology used to detect tumors and cancers and assist in therapeutic strategies. The most widely used markers are circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA). Primary carcinoma of the liver is a malignancy of hepatocytes or intrahepatic biliary epithelial cells. The most common type of liver cancer is hepatocellular carcinoma (HCC), the causes of which mainly include infection with hepatitis B virus (HBV) and/or hepatitis C virus (HCV), alcohol abuse, aflatoxicosis, and nonalcoholic fatty liver disease/ nonalcoholic steatohepatitis. As there are few typical clinical characteristics during the early stage of the disease, early diagnosis of HCC is very challenging. However, CTCs and ctDNA carry tumor-specific information. Therefore, the detection and analysis of CTCs and ctDNA can provide evidence for the early diagnosis of HCC and guide treatment. Furthermore, several studies have indicated that different inducers of HCC cause different DNA mutations, and accordingly, detection of specific mutations in ctDNA will facilitate the determination of the HCC type and help physicians provide distinctive therapies.

Association of HLA-DPA1 and HLA-DPB1 polymorphisms with spontaneous HBsAg seroclearance in Caucasians

BACKGROUND & AIMS

Acute hepatitis B virus (HBV) infections may clear spontaneously or become chronic and run through different phases. The single nucleotide polymorphisms (SNPs) rs3077, rs9277535 and rs9277534 within the human leucocyte antigen (HLA)-DP gene have been found to be associated with HBV susceptibility and persistence in Asians. However, evidence for the influence of these variants in Caucasians has been limited so far. The aim of our study was to investigate the impact of these polymorphisms on the outcome of HBV infections in a large Caucasian population.

METHODS

In this case-control study, we retrospectively analysed 1111 Caucasian individuals, including 618 with chronic HBV infections (CHB), 239 with spontaneous HBsAg seroclearance (SC) and 254 healthy controls (HC). The rs3077, rs9277535 and rs9277534 SNPs were genotyped by a polymerase chain reaction from blood samples and melting curve analysis.

RESULTS

A significant difference in the allele distributions was observed only for the rs3077 SNP between the HC and the CHB group as well as between the SC and CHB groups. The rs3077-C allele was associated with a lower probability for spontaneous HBsAg seroclearance in comparison with the rs3077-T allele (OR 0.704, 95% CI 0.509-0.974; P = 0.033). No association of the three SNPs with the stages of chronic HBV infection was found.

CONCLUSION

This is the first study demonstrating an association of the rs3077-T allele with spontaneous HBsAg seroclearance in Caucasians. Further studies are needed to elucidate the role of HLA-DP variants in disease pathogenesis and their potential role for individualized disease management.

Host genetic factors affecting hepatitis B infection outcomes: Insights from genome-wide association studies

The clinical outcome of Hepatitis B Virus (HBV) infection depends on the success or failure of the immune responses to HBV, and varies widely among individuals, ranging from asymptomatic self-limited infection, inactive carrier state, chronic hepatitis, cirrhosis, hepatocellular carcinoma, to liver failure. Genome-wide association studies (GWAS) identified key genetic factors influencing the pathogenesis of HBV-related traits. In this review, we discuss GWAS for persistence of HBV infection, antibody response to hepatitis B vaccine, and HBV-related advanced liver diseases. HBV persistence is associated with multiple genes with diverse roles in immune mechanisms. The strongest associations are found within the classical human leukocyte antigen (HLA) genes, highlighting the central role of antigen presentation in the immune response to HBV. Associated variants affect both epitope binding specificities and expression levels of HLA molecules. Several other susceptibility genes regulate the magnitude of adaptive immune responses, determining immunity vs tolerance. HBV persistence and nonresponse to vaccine share the same risk variants, implying overlapping genetic bases. On the other hand, the risk variants for HBV-related advanced liver diseases are largely different, suggesting different host-virus dynamics in acute vs chronic HBV infections. The findings of these GWAS are likely to pave the way for developing more effective preventive and therapeutic interventions by personalizing the management of HBV infection.

Genome-wide association pathway analysis to identify candidate single nucleotide polymorphisms and molecular pathways associated with TP53 expression status in HBV-related hepatocellular carcinoma

Background

The aim of this investigation was to identify candidate single nucleotide polymorphisms (SNPs) and molecular pathways associated with tumor protein p53 (TP53) expression status in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC), clarify their potential mechanisms, and generate SNP-to-gene to pathway hypothesis.

Materials and methods

Identify candidate Causal SNPs and Pathways (ICSNPathway) was used to perform pathway analysis based on the results of our previous genome-wide association study of TP53 expression status in 387 HBV-related HCC patients.

Results

Through the ICSNPathway analysis, we identified 18 candidate SNPs and 10 candidate pathways that are associated with TP53 expression status in HBV-related HCC. The strongest mechanism involved the modulation of major histocompatibility complex, class II, DP beta 1 (human leukocyte antigen [HLA]-DPB1-rs1042153), major histocompatibility complex, class II, DQ beta 1 (HLA-DQB1-rs1130399, HLA-DQB1-rs1049056, HLA-DQB1-rs1049059, and HLA-DQB1-rs1049060), and major histocompatibility complex, class II, DR beta 1 (HLA-DRB1-rs35445101). SNPs consequently affected regulatory roles in all the candidate pathways except hematopoietic cell lineage pathways. Association analysis using the GSE14520 data set, Gene Multiple Association Network Integration Algorithm, and Search Tool for the Retrieval of Interacting Genes/Proteins suggests that all genes of the candidate SNPs were associated with TP53. Survival analysis showed that the collagen type VI alpha 3 chain (COL6A3) rs111231885 and COL6A3-rs113155945 and COL6A3 block 4 CC haplotypes with TP53 negative status may have protective effects in HBV-related HCC patients after hepatectomy.

Conclusion

Our pathway analysis identified 18 candidate SNPs and 10 candidate pathways that were associated with TP53 expression status in HBV-related HCC. Among these candidate SNPs, the genetic variation of COL6A3 may be a potential prognostic biomarker of HBV-related HCC.

Identification of additional EHMT2 variant associated with the risk of chronic hepatitis B by GWAS follow-up study

Chronic hepatitis B (CHB) is a precursor to liver cirrhosis and hepatocellular carcinoma, caused by a Hepatitis B viral infection. Genome-wide association studies (GWASs) have been conducted to find genes associated with CHB risk. In previous GWAS, EHMT2 was identified as one of the susceptibility genes for CHB. To further characterize this association and discover possible causal variants, we conducted an additional association study. A total of 11 EHMT2 single-nucleotide polymorphisms (SNP) were selected and genotyped in 3902 subjects (1046 CHB patients and 2856 controls). An additional eight imputed SNPs were also included in further analysis. As a result, rs35875104 showed a strong association with the CHB, along with the previously reported genetic marker for CHB risk, rs652888 (odds ratio (OR) = 0.53, P = 2.20 × 10^-8 at rs35875104 and OR = 1.58, P = 9.90 × 10^-12 at rs652888). In addition, linkage disequilibrium and conditional analysis identified one SNP (rs35875104) as a novel genetic marker for CHB susceptibility. The GRSs (genetic risk scores) were calculated to visualize the combined genetic effects of all known CHB-associated loci, including EHMT2 rs35875104, which was additionally identified in this study. The findings from the present study may be useful for further understanding of the genetic etiology of CHB.

Comprehensive investigation of cytokine- and immune-related gene variants in HBV-associated hepatocellular carcinoma patients

Host genotype may be closely related to the different outcomes of Hepatitis B virus (HBV) infection. To identify the association of variants and HBV infection, we comprehensively investigated the cytokine- and immune-related gene mutations in patients with HBV associated hepatocellular carcinoma (HBV-HCC). Fifty-three HBV-HCC patients, 53 self-healing cases (SH) with HBV infection history and 53 healthy controls (HCs) were recruited, the whole exon region of 404 genes were sequenced at >900× depth. Comprehensive variants and gene levels were compared between HCC and HC, and HCC and SH. Thirty-nine variants (adjusted P<0.0001, Fisher's exact test) and 11 genes (adjusted P<0.0001, optimal unified approach for rare variant association test (SKAT-O) gene level test) were strongly associated with HBV-HCC. Thirty-four variants were from eight human leukocyte antigen (HLA) genes that were previously reported to be associated with HBV-HCC. The novelties of our study are: five variants (rs579876, rs579877, rs368692979, NM_145007:c.*131_*130delTG, NM_139165:exon5:c.623-2->TT) from three genes (REAT1E, NOD-like receptor (NLR) protein 11 (NLRP11), hydroxy-carboxylic acid receptor 2 (HCAR2)) were found strongly associated with HBV-HCC. We found 39 different variants in 11 genes that were significantly related to HBV-HCC. Five of them were new findings. Our data implied that chronic hepatitis B patients who carry these variants are at a high risk of developing HCC.

Role of HLA-DP and HLA-DQ on the clearance of hepatitis B virus and the risk of chronic infection in a multiethnic population

BACKGROUND & AIMS

HBV infection exhibits geographical variation in its distribution in South America. While HBV rates are low in central Argentina, the north-western region exhibits intermediate HBV rates. Unfortunately, the reasons that could explain this difference are still unknown.

METHODS

A total of 1440 Argentines were recruited and grouped into HBV patients, HBV-resolved individuals and healthy controls. Genetic ancestry was assessed by analysis of biparental lineages and ancestry autosomal typing. SNPs of HLA-DPA1 (rs3077), HLA-DPB1 (rs9277542), HLA-DQB1 (rs2856718) and HLA-DQB2 (rs7453920) were determined, and HBV genotyping was performed by phylogenetic analysis in HBV patients.

RESULTS

Native American ancestry prevailed in the north-western region when compared with central Argentina (P<.0001). However, no differences were observed among the three groups of each region. The distribution of HBV genotypes revealed significant differences (P<.0001). Three SNPs (rs3077, rs9277542 and rs7453920) showed a significant association with protection against chronic HBV and viral clearance in both regions. The remaining SNP showed a significant association with susceptibility to chronic HBV. The frequency rates of rs3077-T, related to protection against chronic HBV and viral clearance, were lower in north-western Argentina when compared with central Argentina. The same uneven frequency rates were observed for SNP rs9277542.

CONCLUSIONS

This is the first study addressing the associations between the HLA-DP and HLA-DQ loci and the protection against chronic HBV and viral clearance in a multiethnic South American population. The uneven distribution of HLA-DP and HLA-DQ supports the HBV epidemiological differences observed in these two regions of Argentina with dissimilar ancestry genetic background.

Correlation of HLA-DP/DQ polymorphisms with transplant etiologies and prognosis in liver transplant recipients

Previous study has identified that the genetic variants in the human leukocyte antigen (HLA)-DP/DQ region were strongly associated with hepatitis B virus (HBV) infection. But their roles in liver function recovery after hepatic transplantation were still obscure. This study aimed to investigate whether HLA-DP/DQ polymorphisms were associated with post-transplant etiologies and prognosis in Chinese liver transplant recipients.A total of 144 liver transplant recipients were enrolled, which were divided into 2 groups according to the transplant etiology: HBV-related disease and non-HBV-related disease. HBV-related disease includes 3 subgroups: liver cirrhosis, hepatocellular carcinoma, and progressive HBV hepatitis. Three single-nucleotide polymorphisms HLA-DP (rs3077 and rs9277535) and HLA-DQ (rs7453920) were studied in all recipients by high-resolution melting curve analysis. Liver function indices (albumin, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma-glutamyltranspeptidase, direct bilirubin, total bilirubin) and coagulation indices (prothrombin time, platelet, international normalized ratio, fibrinogen) were routinely tested. After transplant, 10 recipients who were positive for HBsAg or with elevation in HBV virus load were regarded as HBV recurrence.No significant association of HLA-DP/DQ polymorphisms with HBV recurrence or transplant etiology was observed (P < .05). Recipients with HLA-DQ (rs7453920) AG and AA genotype had lower direct bilirubin levels than GG genotype individuals, especially on the 14th day after surgery (17.80 vs. 5.35, P  =  .038). Patients with A alleles displayed earlier liver function recovery than patients with G alleles (7 vs. 6 months). No significant correlation was shown in HLA-DP rs3077 and rs9277535 with HBV infection or liver function recovery (P < .05).Our study concluded that HLA-DP (rs3077 and rs9277535) and HLA-DQ (rs7453920) were not significantly associated with HBV recurrence or HBV susceptibility, but HLA-DQ rs7453920 was related to prognosis of liver transplant recipients. HLA-DQ rs7453920 A might be used as an indicator of earlier recovery and better prognosis after transplantation.

Effect of HLA-DPA1 alleles on chronic hepatitis B prognosis and treatment response

OBJECTIVE

Chronic hepatitis B (CHB) is a major health problem. The outcome of hepatitis B virus (HBV) infection is associated with variations in HLA-DPA1 alleles. The aim of this study was to investigate possible associations of HLA-DPA1 alleles with treatment response and with hepatitis B virus e antigen (HBeAg) seroconversion.

METHODS

Eight different HLA-DPA1 alleles from 246 CHB patients were genotyped by polymerase chain reaction with sequence-specific primers at high resolution to investigate the association of HLA-DPA1 alleles with treatment response, development of cirrhosis, HBeAg seroconversion, and disease reoccurrence upon HBeAg loss.

RESULTS

There was no significant association between HLA-DPA1 alleles and treatment response, development of cirrhosis, or HBeAg seroconversion. However, HLA-DPA1*04:01 allele was significantly more frequently found in patients who redeveloped disease upon HBeAg seroconversion (100% vs 36.8%: p=0.037; Fisher's exact test).

CONCLUSION

HLA-DPA1*04:01 allele may be a risk factor for reoccurrence of CHB after HBeAg seroconversion.

Current hepatitis B virus infection situation in Indonesia and its genetic diversity

Indonesia has a moderate to high endemicity of hepatitis B virus (HBV) infection. The risk for chronic HBV infection is highest among those infected during infancy. Since 1997, hepatitis B (HepB) vaccination of newborns has been fully integrated into the National Immunization Program. Although HBV infection has been reduced by the universal newborn HepB immunization program, it continues to occur in Indonesia. The low birth dose coverage and the presence of vaccine escape mutants might contribute to this endemicity among children. Although limited information is available for an analysis of occult HBV infection (OBI), several variations and substitutions in the pre-S/S region have been detected in Indonesian HBV strains. Additionally, persistent infection and disease progression of chronic hepatitis B are related to not only viral factors but also the host genome. Indonesia is one of the most ethnically heterogeneous nations, with Javanese and Sundanese as the two highest ethnic groups. This multi-ethnicity makes genomic research in Indonesia difficult. In this article, we focused on and reviewed the following aspects: the current hepatitis B immunization program and its efficacy, OBI, HBV infection among high-risk patients, such as hemodialysis patients, and research regarding the host genome in Indonesia.

Host Genetic Variants in HLA Loci Influence Risk for Hepatitis B Virus Infection in Children

BACKGROUND

Hepatitis B virus (HBV) infection is a serious public health problem in China and worldwide. Mother-to-child transmission is one of HBV's main transmission routes in highly endemic regions. Genome-wide association studies (GWAS) identify single nucleotide polymorphisms (SNPs) at HLA loci as associated with HBV infection. However, the mechanisms of HBV perinatal transmission and breakthrough in children have not yet been clearly defined.

OBJECTIVES

We aimed to explore the association between SNPs at HLA loci and HBV infection and breakthrough in children.

METHODS

A total of 274 HBV-infected children and 353 controls were selected among children aged between 6 months and 12 years in China. Seven SNPs at HLA-DP and HLA-DQ loci were genotyped to analyze their association with HBV infection in children.

RESULTS

Alleles G in both HLA-DPA1 rs3077 and HLA-DPB1 rs9277535 were found to be significantly associated with HBV infection in children with odds ratios (OR) of 1.309 (95% CI 1.046 to 1.639) and 1.411 (95% CI 1.125 to 1.771), respectively. In addition, overdominant analysis found that the rs2281388 (HLA-DPB1) GA genotype and the rs9366816 (HLA-DPB2) TC genotype were related to HBV infection (rs2281388, OR = 1.422, 95% CI: 1.032-1.961; rs9366816, OR = 1.444, 95% CI: 1.045-1.994). Furthermore, this study highlighted that rs9277535 was also significantly associated with HBV breakthrough infection in children whose mothers were positive for hepatitis B surface antigen (HBsAg).

CONCLUSIONS

Our study confirmed that genetic variants in HLA-DPA1 and HLA-DPB1 loci have significant associations with HBV infection, especially with HBV breakthrough in children. This study provides insight into HBV infection in children and is valuable for the targeted management of, and control strategies for, this disease.

A randomized clinical trial of peginterferon alpha-2b with or without entecavir in patients with HBeAg-negative chronic hepatitis B: Role of host and viral factors associated with treatment response

Combining peginterferon (PEG-IFN) and a potent nucleoside/nucleotide analogue might improve treatment response in patients with chronic hepatitis B (CHB). The aims of this study were to compare the efficacy of PEG-IFN alpha-2b with or without entecavir in HBeAg-negative CHB and to investigate predictors of response. A total of 126 treatment-naïve patients were randomly assigned to receive monotherapy (n = 63) or combination therapy (n = 63) for 48 weeks. Virological response (VR) was defined as HBV DNA level <2000 IU/mL at week 96. Baseline factors including polymorphisms in the IFNL3 (rs12979860) and HLA-DPA1 (rs3077) genes and on-treatment viral kinetics were determined. At week 48, rates of undetectable HBV DNA were lower in the monotherapy than combination groups, but rates of HBsAg clearance and decline were comparable. At week 96, there was no difference between the corresponding groups regarding virological response (41.3% vs 38.1%, P = 0.856), HBsAg clearance (9.5% vs 4.8%, P = 0.491) and HBsAg decline. Baseline HBsAg level [odds ratio (OR): 3.14 (1.34-7.69), P = 0.012] and rs3077 polymorphism [OR: 2.78 (1.27-6.11), P = 0.011] were independent predictors of response. Patients carried GG genotype of rs3077 with low baseline HBV (<1000 IU/mL) had high probability of achieving VR (76.5%) and HBsAg clearance (29.4%). None of the patients without decrease in HBsAg combined with <2 log10 HBV DNA decline at week 12 achieved a virological response. In conclusion, the combination therapy lead to greater on-treatment HBV DNA suppression but did not improve virological response and HBsAg clearance/decline over monotherapy. Host and viral factors could help optimize decision-making at baseline and during PEG-IFN-based therapy.

Protective effects of HLA-DPA1/DPB1 variants against Hepatitis B virus infection in an Indonesian population

Human leukocyte antigen (HLA) DPA1/DPB1 variants have been reported to influence Hepatitis B virus (HBV) infection. HLA-DPA1/DPB1 plays a pivotal role in antigen presentation to CD4(+) helper T cells and influences the outcome of HBV infection. To investigate the influence of HLA-DP variants on the outcome of HBV infection in an Indonesian population where it has the third-highest prevalence of HBV infection worldwide, we performed a case-control study of 686 participants, including patients with HBV-related advanced or nonadvanced liver disease, patients with spontaneously resolved HBV, and healthy controls. Single-nucleotide polymorphisms in HLA-DPA1 (rs3077) and HLA-DPB1 (rs3135021, rs9277535, and rs228388) were genotyped using real-time TaqMan® genotyping assays. Because rs2281388 deviated from Hardy-Weinberg equilibrium, it was excluded from subsequent analyses. The results of logistic regression analyses showed that the HLA-DPB1 rs9277535 variants were associated with a reduced risk of persistent HBV infection (odds ratio [OR] 0.70, 95% confidence interval [95% CI] 0.52-0.96, P=0.026, additive genetic model; OR 0.60, 95% CI 0.38-0.96, P=0.033, dominant genetic model). The HLA-DPA1 rs3077 variant was associated with a protective effect increasing the spontaneously resolved HBV infection (OR 0.64, 95% CI 0.41-0.98, P=0.039, dominant genetic model). By contrast, the HLA-DPB1 rs3135021 variant was not associated with the outcome of HBV infection, including susceptibility, spontaneously resolved, or disease progression. Combinations of haplotype markers were also associated with HBV susceptibility (CA for rs3077-rs9277535, OR 0.57, 95% CI 0.36-0.92, P=0.021; GA for rs3135021-rs9277535, OR 0.56, 95% CI 0.36-0.86, P=0.0087). In conclusion, these findings confirm that HLA-DPA1/DPB1 variants were associated with the outcomes of HBV infection in an Indonesian population.

Quantitative assessment of common genetic variations in HLA-DP with hepatitis B virus infection, clearance and hepatocellular carcinoma development

Hepatitis B virus (HBV) infection is the predominant risk factor for chronic hepatitis B (CHB), liver cirrhosis (LC) and hepatocellular carcinoma (HCC). Recently, genome-wide association studies have identified human leukocyte antigen (HLA)-DP polymorphisms (rs3077 and rs9277535) as a new chronic HBV infection susceptibility locus. Since then, the relationship between HLA-DP polymorphisms and various outcomes of HBV infection has been reported. However, the results have been inconclusive. To derive a more precise estimation of the relationship between HLA-DP polymorphisms and various outcomes of HBV infection, a meta-analysis of 62,050 subjects from 29 case-control studies was performed. We found that rs3077 and rs9277535 in HLA-DP significantly decreased HBV infection risks and increased HBV clearance possibility in a dose-dependent manner. In the subgroup analysis by ethnicity, study design and sample size, significant associations were found for these polymorphisms in almost all comparisons. Meanwhile, haplotype analyses of the two polymorphisms revealed a significant association between the combination of these alleles and HBV infection outcomes. However, no significant results were observed in HCC development. Our results further confirm that genetic variants in the HLA-DP locus are strongly associated with reduced HBV infection and increased the likelihood of spontaneous viral clearance.

Association of interferon-gamma inducible protein 10 polymorphism with treatment response to pegylated interferon in HBeAg-positive chronic hepatitis B

BACKGROUND

Interferon-gamma inducible protein 10 (IP-10) plays an important role in the clinical outcome of chronic hepatitis B (CHB). This study aimed to investigate the association between single nucleotide polymorphisms (SNPs) G-201A of the IP-10 gene and treatment response to pegylated interferon (PEG-IFN) in patients with hepatitis B e antigen (HBeAg)-positive CHB.

METHODS

We retrospectively analysed data of patients with HBeAg-positive CHB treated with PEG-IFN for 48 weeks. Virological response (VR) was defined as HBeAg clearance and HBV DNA <2,000 IU/ml at 24 weeks post-treatment. The SNPs G-201A, IFNL3 (rs12979860) and HLA-DPA1 (rs3077) were assessed.

RESULTS

Among 107 patients, VR was achieved in 45 (42.1%) patients. Hepatitis B surface antigen (HBsAg) clearance and decline (<100 IU/ml) were observed in 10 (9.3%) and 22 (20.6%) patients, respectively. The distribution of GG, GA and AA genotypes of G-201A was 76.6%, 19.6% and 3.7%, respectively. Patients with GG genotype, compared to those with non-GG genotype, achieved higher VR rate (48.8% versus 19.2%; P=0.011), decreased HBsAg (25.6% versus 4.0%; P=0.019), and demonstrated a trend in HBsAg clearance (11.0% versus 4%; P=0.294). Patients with GG genotype had more rapid HBsAg decline and higher baseline serum IP-10 levels than those with non-GG genotype (432.2 ±339.0 versus 257.3 ±145.7 pg/ml; P=0.028). SNPs rs12979860 and rs3077 were not associated with VR. Logistic regression analysis suggested that SNP G-201A was an independent predictor of VR (odds ratio 3.81, 95% CI 1.31, 11.12; P=0.014).

CONCLUSIONS

Data from this study demonstrated for the first time that IP-10 polymorphism is independently associated with treatment response to PEG-IFN in patients with HBeAg-positive CHB.

Human Leukocyte Antigen Class II Alleles Are Associated with Hepatitis C Virus Natural Susceptibility in the Chinese Population

Human leukocyte antigen (HLA) class II molecule influences host antigen presentation and anti-viral immune response. The aim of this study was to investigate whether single nucleotide polymorphisms (SNPs) within HLA class II gene were associated with different clinical outcomes of hepatitis C virus (HCV) infection. Three HLA class II SNPs (rs3077, rs2395309 and rs2856718) were genotyped by TaqMan assay among Chinese population, including 350 persistent HCV infection patients, 194 spontaneous viral clearance subjects and 973 HCV-uninfected control subjects. After logistic regression analysis, the results indicated that the rs2856718 TC genotype was significantly associated with the protective effect of the HCV natural susceptibility (adjusted OR: 0.712, 95% CI: 0.554–0.914) when compared with reference TT genotype, and this remained significant after false discovery rate (FDR) correction (p = 0.024). Moreover, the protective effect of rs2856718 was observed in dominant genetic models (adjusted OR: 0.726, 95% CI: 0.574–0.920), and this remained significant after FDR correction (p = 0.024). In stratified analysis, a significant decreased risk was found in rs2856718C allele in the male subgroup (adjusted OR: 0.778, 95% CI: 0.627–0.966) and hemodialysis subgroup (adjusted OR: 0.713, 95% CI: 0.552–0.921). Our results indicated that the genetic variations of rs2856718 within the HLA-DQ gene are associated with the natural susceptibility to HCV infection among the Chinese population.

Is mother-to-infant transmission the most important factor for persistent HBV infection?

Of the infants born to hepatitis B surface antigen (HBsAg)-positive mothers globally, 42.1% who did not receive hepatitis B virus (HBV) passive-active immunoprophylaxis and 2.9% of infants who received the immunoprophylaxis acquired HBV infection perinatally. Moreover, perinatal infection occurred in 84.2% (18.8%-100%) and 8.7% (0.0-21.0%) of infants born to hepatitis B e-antigen (HBeAg)-positive mothers who did not and did receive immunoprophylaxis, respectively; by contrast, the infection rates were 6.7% (0.0-15.4%) and 0.4% (0.0-2.5%) for infants born to HBeAg-negative-carrier mothers, respectively. The chronicity rates of HBV infection acquired perinatally were 28.2% (17.4%-33.9%) in infants born to HBeAg-negative mothers and 64.5% (53.5%-100%) in infants born to HBeAg-positive mothers. HBV mother-to-child transmission was more frequent in East Asia relative to other areas. In addition to differences in the endemic HBV genotype, the interchange of allelic dominance in genetic polymorphisms in HLA class II and NF-κB between the Chinese and European populations may explain why chronic HBV infection frequently affects the Chinese. The risk of progressing into chronic infection was inversely related to the age of children at the time of horizontal transmission. To further diminish HBV chronic infection, it is necessary to enforce antiviral treatment after the 28th week of gestation for HBeAg-positive mothers and to improve the health habits of carrier mothers and household sanitary conditions.

HLA-DPB1 Variant Effect on Hepatitis B Virus Clearance and Liver Cirrhosis Development Among Southwest Chinese Population

BACKGROUND

Previous studies have shown that genetic variants in HLA-DP genes affect disease progression in hepatitis B virus (HBV) infection.

OBJECTIVES

We aimed to evaluate possible association between HLA-DPB1 rs9277534 polymorphism and different clinical complications of hepatitis B virus (HBV) infection.

MATERIALS AND METHODS

Snapshot assay was used to investigate the association of rs9277534 polymorphism in 342 patients with persistent HBV infection and 342 age and gender-matched HBV spontaneous clearance controls. Patients were categorized into asymptomatic HBV carriers (AsC, n = 104), chronic hepatitis B (CHB, n = 116), and liver cirrhosis (LC, n = 122) subgroups.

RESULTS

There was a significantly higher proportion of the rs9277534 minor allele A in HBV spontaneous clearance control than that in HBV persistent infection group (OR = 0.58, 95%CI = 0.46-0.73, P < 0.0001). Genotypic analysis showed that GA and AA genotypes were associated with HBV spontaneous clearance (GA: OR = 0.56, 95%CI = 0.40-0.79, P = 0.019; AA: OR = 0.24, 95%CI = 0.14-0.44, P < 0.0001). A significant difference was found between AsC and LC groups in the distribution of AA genotype (OR = 9.32, 95%CI = 1.293-67.14, P = 0.027).

CONCLUSIONS

Variant at rs9277534 could affect both the spontaneous clearance of HBV infection and progression from asymptomatic HBV carriers to HBV-related liver cirrhosis in Southwest Han Chinese population.