Genome-wide association study confirming association of HLA-DP with protection against chronic hepatitis B and viral clearance in Japanese and Korean

High-resolution African HLA resource uncovers HLA-DRB1 expression effects underlying vaccine response

How human genetic variation contributes to vaccine effectiveness in infants is unclear, and data are limited on these relationships in populations with African ancestries. We undertook genetic analyses of vaccine antibody responses in infants from Uganda (n = 1391), Burkina Faso (n = 353) and South Africa (n = 755), identifying associations between human leukocyte antigen (HLA) and antibody response for five of eight tested antigens spanning pertussis, diphtheria and hepatitis B vaccines. In addition, through HLA typing 1,702 individuals from 11 populations of African ancestry derived predominantly from the 1000 Genomes Project, we constructed an imputation resource, fine-mapping class II HLA-DR and DQ associations explaining up to 10% of antibody response variance in our infant cohorts. We observed differences in the genetic architecture of pertussis antibody response between the cohorts with African ancestries and an independent cohort with European ancestry, but found no in silico evidence of differences in HLA peptide binding affinity or breadth. Using immune cell expression quantitative trait loci datasets derived from African-ancestry samples from the 1000 Genomes Project, we found evidence of differential HLA-DRB1 expression correlating with inferred protection from pertussis following vaccination. This work suggests that HLA-DRB1 expression may play a role in vaccine response and should be considered alongside peptide selection to improve vaccine design.

Molecular Analysis of HLA Genes in Romanian Patients with Chronic Hepatitis B Virus Infection

Hepatitis B, a persistent inflammatory liver condition, stands as a significant global health issue. In Romania, the prevalence of chronic hepatitis B virus (CHB) infection ranks among the highest in the European Union. The HLA genotype significantly impacts hepatitis B virus infection progression, indicating that certain HLA variants can affect the infection's outcome. The primary goal of the present work is to identify HLA alleles and specific amino acid residues linked to hepatitis B within the Romanian population. The study enrolled 247 patients with chronic hepatitis B; HLA typing was performed using next-generation sequencing. This study's main findings include the identification of certain HLA alleles, such as DQB1*06:03:01, DRB1*13:01:01, DQB1*06:02:01, DQA1*01:03:01, DRB5*01:01:01, and DRB1*15:01:01, which exhibit a significant protective effect against HBV. Additionally, the amino acid residue alanine at DQB1_38 is associated with a protective role, while valine presence may signal an increased risk of hepatitis B. The present findings are important in addressing the urgent need for improved methods of diagnosing and managing CHB, particularly when considering the disease's presence in diverse population groups and geographical regions.

The effect of HLA-DP gene polymorphisms in Plasmodium Vivax-induced malaria susceptibility

Plasmodium vivax is the second most common Plasmodium parasite causing clinically serious symptoms and death from malaria. It is an important cause of morbidity and mortality, especially in Asia, the Middle East, and South America. Human leukocyte antigen molecules are responsible for presenting foreign antigens to T cells. Polymorphisms in HLA genes affect antigen presentation. HLA alleles involved in the presentation of P. vivax antigens affect the antibody response. The present study aimed to reveal the relationship of rs3077 and rs9277535 polymorphisms in HLA-DP genes with malaria caused by P. vivax for the first time in the worldwide. In the present research, rs3077 and rs9277535 polymorphisms were investigated in a case-control study of 124 patients with P. vivax-induced malaria and 211 healthy persons by using a real-time polymerase chain reaction (RT-PCR). The results showed that the G alleles of rs3077 and rs9277535 polymorphisms were detected as protective alleles, while the A alleles of both polymorphisms increase the risk of susceptibility to malaria disease. The results of the present study showed that both polymorphisms have a major effect on the susceptibility to malaria caused by P. vivax. We recommend that this study should be conducted in a different population with a larger sample size to confirm our results.

Identification of 13 Novel Loci in a Genome-Wide Association Study on Taiwanese with Hepatocellular Carcinoma

Liver cancer is caused by complex interactions among genetic factors, viral infection, alcohol abuse, and metabolic diseases. We conducted a genome-wide association study and polygenic risk score (PRS) model in Taiwan, employing a nonspecific etiology approach, to identify genetic risk factors for hepatocellular carcinoma (HCC). Our analysis of 2836 HCC cases and 134,549 controls revealed 13 novel associated loci such as the FAM66C gene, noncoding genes, liver-fibrosis-related genes, metabolism-related genes, and HCC-related pathway genes. We incorporated the results from the UK Biobank and Japanese database into our study for meta-analysis to validate our findings. We also identified specific subtypes of the major histocompatibility complex that influence both viral infection and HCC progression. Using this data, we developed a PRS to predict HCC risk in the general population, patients with HCC, and HCC-affected families. The PRS demonstrated higher risk scores in families with multiple HCCs and other cancer cases. This study presents a novel approach to HCC risk analysis, identifies seven new genes associated with HCC development, and introduces a reproducible PRS model for risk assessment.

An HBV susceptibility variant of KNG1 modulates the therapeutic effects of interferons α and λ1 in HBV infection by promoting MAVS lysosomal degradation

BACKGROUND

Hepatitis B virus (HBV) infection is one of the main causes of hepatocellular carcinoma (HCC). The relationship between HBV infection and the host genome as well as their underlying mechanisms remain largely unknown.

METHODS

In this study, we performed a whole-genome exon sequencing analysis of 300 sib-pairs of Chinese HBV-infected families with the goal of identifying variants and genes involved in HBV infection. A site-direct mutant plasmid was used to investigate the function of SNP rs76438938 in KNG1. The functional and mechanical studies of KNG1 were conducted with in vitro liver cell lines and a hydrodynamic injection model in vivo. The impact of KNG1 on HBV infection therapy was determined in hepatocytes treated with IFN-α/λ1.

FINDINGS

Our whole-exon association study of 300 families with hepatitis B infection found that SNP rs76438938 in KNG1 significantly increased the risk for HBV infection, and the rs76438938-T allele was found to promote HBV replication by increasing the stability of KNG1 mRNA. By competitively binding HSP90A with MAVS, KNG1 can inhibit the expression of types I and III IFNs by promoting MAVS lysosomal degradation. Such suppression of IFN expression and promotion of HBV replication by Kng1 were further demonstrated with an animal model in vivo. Lastly, we showed that the rs76438938-C allele can improve the therapeutic effect of IFN-α and -λ1 in HBV infection.

INTERPRETATION

This study identified a SNP, rs76438938, in a newly discovered host gene, KNG1, for its involvement in HBV infection and treatment effect through modulating the cellular antiviral process.

FUNDING

This study was supported in part by the Independent Task of State Key Laboratory for Diagnosis and Treatment of Infectious Diseases of the First Affiliated Hospital of Zhejiang University, the China Precision Medicine Initiative (2016YFC0906300), and the Research Center for Air Pollution and Health of Zhejiang University.

Common Genetic Variants of Response to Hepatitis B Vaccines Correlate with Risks of Chronic Infection of Hepatitis B Virus: A Community-Based Case-Control Study

Hepatitis B (HB) vaccination effectively reduces the risks of chronic infection with the hepatitis B virus (HBV). It is unknown whether there is a common genetic determinant for response to the HB vaccine and susceptibility to chronic HBV infection. This case-control study, which included 193 chronic HBV carriers and 495 non-carriers, aimed to explore the effects of the most significant single nucleotide polymorphisms (SNPs) in response to the HB vaccine on the risks of chronic HBV infection. Out of 13 tested SNPs, the genotype distributions of four SNPs at the human leukocyte antigen (HLA) class II region, including rs34039593, rs614348, rs7770370, and rs9277535, were significantly different between HBV carriers and non-carriers. The age-sex-adjusted odds ratios (OR) of chronic HBV infection for rs34039593 TG, rs614348 TC, rs7770370 AA, and rs9277535 AA genotypes were 0.51 (95% confidence interval [CI], 0.33-0.79; p = 0.0028), 0.49 (95% CI, 0.32-0.75; p = 6.5 × 10^-4), 0.33 (95% CI, 0.18-0.63; p = 7.4 × 10^-4), and 0.31 (95% CI, 0.14-0.70; p = 0.0043), respectively. Multivariable analyses showed that rs614348 TC and rs7770370 AA genotypes were significantly independent protectors against chronic HBV infection. The multivariable-adjusted ORs for subjects with none, either one, or both of the protective genotypes were 1.00 (referent), 0.47 (95% CI: 0.32-0.71; p = 3.0 × 10^-4), and 0.16 (95% CI: 0.05-0.54; p = 0.0032), respectively. Among eight HBeAg-positive carriers, only one of them carried a protective genotype. This study shows that response to the HB vaccine and susceptibility to chronic HBV infection share common genetic determinants and indicates that HLA class II members are the main responsible host genetic factors.

Polymorphisms within DIO2 and GADD45A genes increase the risk of liver disease progression in chronic hepatitis b carriers

The study enrolled 284 patients with chronic hepatitis B virus infection. Participants included people with mild fibrotic lesions (32.5%), moderate to severe fibrotic lesions (27.5%), cirrhotic lesions (22%), hepatocellular carcinoma (HCC) in 5%, and people with no fibrotic lesions in 13%. Eleven SNPs within DIO2, PPARG, ATF3, AKT, GADD45A, and TBX21 were genotyped by mass spectrometry. The rs225014 TT (DIO2) and rs10865710 CC (PPARG) genotypes were independently associated with susceptibility to advanced liver fibrosis. However, cirrhosis was more prevalent in individuals with the GADD45A rs532446 TT and ATF3 rs11119982 TT genotypes. In addition, the rs225014 CC variant of DIO2 was more frequently found in patients with a diagnosis of HCC. These findings suggest that the above SNPs may play a role in HBV-induced liver damage in a Caucasian 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.

Impact of Sarcopenia and Myosteatosis in Non-Cirrhotic Stages of Liver Diseases: Similarities and Differences across Aetiologies and Possible Therapeutic Strategies

Sarcopenia is defined as a loss of muscle strength, mass and function and it is a predictor of mortality. Sarcopenia is not only a geriatric disease, but it is related to several chronic conditions, including liver diseases in both its early and advanced stages. Despite the increasing number of studies exploring the role of sarcopenia in the early stages of chronic liver disease (CLD), its prevalence and the relationship between these two clinical entities are still controversial. Myosteatosis is characterized by fat accumulation in the muscles and it is related to advanced liver disease, although its role in the early stages is still under researched. Therefore, in this narrative review, we firstly aimed to evaluate the prevalence and the pathogenetic mechanisms underlying sarcopenia and myosteatosis in the early stage of CLD across different aetiologies (mainly non-alcoholic fatty liver disease, alcohol-related liver disease and viral hepatitis). Secondly, due to the increasing prevalence of sarcopenia worldwide, we aimed to revise the current and the future therapeutic approaches for the management of sarcopenia in CLD.

Hepatitis B virus persistent infection-related single nucleotide polymorphisms in HLA regions are associated with viral load in hepatoma families

BACKGROUND

Genome-wide association studies from Asia indicate that HLA-DP and HLA-DQ loci are important in persistent hepatitis B virus (HBV) infections. One of the key elements for HBV-related carcinogenesis is persistent viral replication and inflammation.

AIM

To examine genetic and nongenetic factors with persistent HBV infection and viral load in families with hepatocellular carcinoma (HCC).

METHODS

The HCC families included 301 hepatitis B surface antigen (HBsAg) carriers and 424 noncarriers born before the nationwide vaccination program was initiated in 1984. Five HBV-related single nucleotide polymorphisms (SNPs) — rs477515, rs9272105, rs9276370, rs7756516, and rs9277535 — were genotyped. Factors associated with persistent HBV infection and viral load were analyzed by a generalized estimating equation.

RESULTS

In the first-stage persistent HBV study, all SNPs except rs9272105 were associated with persistent infection. A significantly higher area under the reciprocal operating characteristic curve for nongenetic factors vs genetic factors (P < 0.001) suggests that the former play a major role in persistent HBV infection. In the second-stage viral load study, we added 8 HBsAg carriers born after 1984. The 309 HBsAg carriers were divided into low (n = 162) and high viral load (n = 147) groups with an HBV DNA cutoff of 10⁵ cps/mL. Sex, relationship to the index case, rs477515, rs9272105, and rs7756516 were associated with viral load. Based on the receiver operating characteristic curve analysis, genetic and nongenetic factors affected viral load equally in the HCC family cohort (P = 0.3117).

CONCLUSION

In these east Asian adults, the mechanism of persistent HBV infection-related SNPs was a prolonged viral replication phase.

MS-Based HLA-II Peptidomics Combined With Multiomics Will Aid the Development of Future Immunotherapies

Immunotherapies have emerged to treat diseases by selectively modulating a patient's immune response. Although the roles of T and B cells in adaptive immunity have been well studied, it remains difficult to select targets for immunotherapeutic strategies. Because human leukocyte antigen class II (HLA-II) peptides activate CD4+ T cells and regulate B cell activation, proliferation, and differentiation, these peptide antigens represent a class of potential immunotherapy targets and biomarkers. To better understand the molecular basis of how HLA-II antigen presentation is involved in disease progression and treatment, systematic HLA-II peptidomics combined with multiomic analyses of diverse cell types in healthy and diseased states is required. For this reason, MS-based innovations that facilitate investigations into the interplay between disease pathologies and the presentation of HLA-II peptides to CD4+ T cells will aid in the development of patient-focused immunotherapies.

Genome-wide copy number variation analysis of hepatitis B infection in a Japanese population

Genome-wide association studies have been performed to identify common genetic variants associated with hepatitis B (HB). However, little is known about copy number variations (CNVs) in HB. In this study, we performed a genome-wide CNV analysis between 1830 healthy controls and 1031 patients with HB infection after quality control. Using signal calling by the Axiom Analysis Suite and CNV detection by PennCNV software, we obtained a total of 4494 CNVs across all individuals. The genes with CNVs that were found only in the HB patients were associated with the immune system, such as antigen processing. A gene-level CNV association test revealed statistically significant CNVs in the contactin 6 (CNTN6) gene. Moreover, we also performed gene-level CNV association tests in disease subgroups, including hepatocellular carcinoma patients, liver cirrhosis patients, and HBV carriers, including asymptomatic carriers and patients with HBV-derived chronic hepatitis. Our findings from germline cells suggested that patient-specific CNVs may be inherent genetic risk factors for HB.

The risk of contracting the hepatitis B virus may be linked to the number of copies of certain genes in an individual’s genome. A Japanese team led by Masataka Kikuchi, Osaka University, and Akihiro Nakaya, University of Tokyo, looked for repeated segments of the genome, known as copy number variants (CNVs), that differed between people with hepatitis B infections and those without. Studying around 3000 individuals of Japanese descent, the researchers identified several rare CNVs associated with immune function in hepatitis-affected individuals. They also found a common CNV in a gene called CNTN6 that the hepatitis B virus often uses to integrate itself into the genome of liver cells, a process that can lead to cancer. The findings underscore the importance of CNVs as inherited risk factors for hepatitis B and other viral infections.

Genome-wide association study identifies new loci associated with risk of HBV infection and disease progression

BACKGROUND

Recent studies have identified susceptibility genes of HBV clearance, chronic hepatitis B, liver cirrhosis, hepatocellular carcinoma, and showed the host genetic factors play an important role in these HBV-related outcomes.

METHODS

Collected samples from different outcomes of HBV infection and performed genotyping by Affymetrix 500 k SNP Array. GCTA tool, PLINK, and Bonferroni method were applied for analysis of genotyping and disease progression. ANOVA was used to evaluate the significance of the association between biomarkers and genotypes in healthy controls. PoMo, FST, Vcftools and Rehh package were used for building the racial tree and population analysis. FST statistics accesses 0.15 was used as a threshold to detect the signature of selection.

RESULTS

There are 1031 participants passed quality control from 1104 participants, including 275 HBV clearance, 92 asymptomatic persistence infection (ASPI), 93 chronic hepatitis B (CHB), 188 HBV-related decompensated cirrhosis (DC), 214 HBV-related hepatocellular carcinoma (HCC) and 169 healthy controls (HC). In the case-control study, one novel locus significantly associated with CHB (SNP: rs1264473, Gene: GRHL2, P = 1.57 × 10-6) and HCC (SNP: rs2833856, Gene: EVA1C, P = 1.62 × 10-6; SNP: rs4661093, Gene: ETV3, P = 2.26 × 10-6). In the trend study across progressive stages post HBV infection, one novel locus (SNP: rs1537862, Gene: LACE1, P = 1.85 × 10-6), and three MHC loci (HLA-DRB1, HLA-DPB1, HLA-DPA2) showed significant increased progressive risk from ASPI to CHB. Underlying the evolutionary study of HBV-related genes in public database, the derived allele of two HBV clearance related loci, rs3077 and rs9277542, are under strong selection in European population.

CONCLUSIONS

In this study, we identified several novel candidate genes associated with individual HBV infectious outcomes, progressive stages, and liver enzymes. Two SNPs that show selective significance (HLA-DPA1, HLA-DPB1) in non-East Asian (European, American, South Asian) versus East Asian, indicating that host genetic factors contribute to the ethnic disparities of susceptibility of HBV infection. Taken together, these findings provided a new insight into the role of host genetic factors in HBV related outcomes and progression.

A non-synonymous variant rs12614 of complement factor B associated with risk of chronic hepatitis B in a Korean population

Background

Hepatitis B is known to cause several forms of liver diseases including chronic hepatitis B (CHB), and hepatocellular carcinoma. Previous genome-wide association study of CHB risk has demonstrated that rs12614 of complement factor B (CFB) was significantly associated with CHB risk. In this study, fine-mapping study of previously reported GWAS single nucleotide polymorphism (SNP; CFB rs12614) was performed to validate genetic effect of rs12614 on CHB susceptibility and identify possible additional causal variants around rs12614 in a Korean population. This association study was conducted in order to identify genetic effects of CFB single nucleotide polymorphisms (SNPs) and to identify additional independent CHB susceptible causal markers within a Korean population.

Methods

A total of 10 CFB genetic polymorphisms were selected and genotyped in 1716 study subjects comprised of 955 CHB patients and 761 population controls.

Results

A non-synonymous variant, rs12614 (Arg32Trp) in exon2 of CFB, had significant associations with risk of CHB (odds ratio = 0.43, P = 5.91 × 10^− 10). Additional linkage disequilibrium and conditional analysis confirmed that rs12614 had independent genetic effect on CHB susceptibility with previously identified CHB markers. The genetic risk scores (GRSs) were calculated and the CHB patients had higher GRSs than the population controls. Moreover, OR was found to increase significantly with cumulative GRS.

Conclusions

rs12614 showed significant genetic effect on CHB risk within the Korean population. As such rs12614 may be used as a possible causal genetic variant for CHB susceptibility.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12881-020-01177-w.

Genetic association study of interferon lambda 3, CD27, and human leukocyte antigen-DPB1 with dengue severity in Thailand

BACKGROUND

Dengue patients develop different disease severity ranging from mild (dengue fever [DF]) to severe forms (dengue hemorrhagic fever [DHF] and the fatal dengue shock syndrome [DSS]). Host genetics are considered to be one factor responsible for the severity of dengue outcomes. To identify genes associated with dengue severity that have not been studied yet, we performed genetic association analyses of interferon lambda 3 (IFNL3), CD27, and human leukocyte antigen-DPB1 (HLA-DPB1) genes in Thai dengue patients.

METHODS

A case-control association study was performed in 877 children (age ≤ 15 years) with dengue infection (DF, n = 386; DHF, n = 416; DSS, n = 75). A candidate single nucleotide polymorphism of each of IFNL3, CD27, and HLA-DPB1 was selected to be analyzed. Genotyping was performed by TaqMan real-time PCR assay, and the association with dengue severity was examined.

RESULTS

The rs9277534 variant of HLA-DPB1 was weakly associated with DHF. The genotype GG and G allele conferred protection against DHF (p = 0.04, odds ratio 0.74 for GG genotype, p = 0.03, odds ratio 0.79 for G allele). The association became borderline significant after adjusting for confounders (p = 0.05, odds ratio 0.82). No association was detected for IFNL3 or CD27.

CONCLUSIONS

The present study demonstrated the weak association of the rs9277534 variant of HLA-DPB1 with protection against DHF. This variant is in the 3' untranslated region and affects HLA-DPB1 surface protein expression. Our finding suggests that HLA-DPB1 may be involved in DHF pathogenesis.

Human genetic susceptibility to hepatitis B virus infection

Hepatitis B virus (HBV) infection is still a serious health threat worldwide. The outcomes of HBV infection consist of spontaneous HBV clearance and chronic HBV infection. Multiple factors contribute to the disparity of HBV infection outcomes, including host factors, viral factors and environmental factors. The present review comprehends the current researches mainly focusing on the relationships between genetic determinants, including single nucleotide polymorphisms (SNPs) and haplotypes, and susceptibility of HBV infection, namely chronic (persistent) HBV infection and HBV clearance. A number of determinants in the chromosomes, including mutations in human leukocyte antigens (HLAs), cytokines genes, toll-like receptors (TLRs), and other genes are related to the human susceptibility to HBV infection. Among the above variants, some of those in HLAs have been studied and replicated in multiple-ethnic populations and came to consistent conclusions, while some others are novel and need to be evaluated further.

Suppression of complement component 2 expression by hepatitis B virus contributes to the viral persistence in chronic hepatitis B patients

Previously, we identified rare missense mutations of complement component 2 (C2) to be associated with chronic hepatitis B (CHB) by exome sequencing. However, up to now, little is known about the role of C2 in CHB. In the present study, we aimed to perform preliminary exploration about the underlying role of C2 in CHB. Serum samples from 113 CHB patients and 30 healthy controls, and liver biopsy samples from 5 CHB patients and 3 healthy controls were obtained from the Third Affiliated Hospital of Sun Yat-sen University between January 2018 and January 2020. HepG2.2.15 and HepG2-NTCP cells infected with HBV were used to examine the influence of HBV infection on C2 expression. IFN-treated HepG2.2.15 cells were used to assess the effect of IFN on C2 expression. C2-overexpressing or C2-silencing HepG2.2.15 cells were constructed to evaluate the effect of C2 on HBV infection. Western blot and RT-qPCR were used to measure C2 expression in biopsy samples. HBeAg and HBsAg in culture medium and C2 of serum samples were measured by ELISA. HBV-DNA was measured by RT-qPCR. GSE84044, GSE54747 and GSE27555 were downloaded from GEO. C2 expression in liver tissue and serum was significantly lower in CHB patients compared to healthy controls, and significantly higher C2 expression was found in CHB patients with lower ALT, AST, Scheuer grade and stages compared to CHB patients with higher ALT, AST, Scheuer grades and Scheuer stage. Besides, HBV infection could decrease C2 expression by increasing expression of Sp1 and reducing expression of HDAC4. Moreover, C2 could enhance the anti-virus effect of IFN on HepG2.2.15 cells and also inhibit HBV replication in HepG2.2.15 cells by inhibition of p38-MAPK signalling pathway. In conclusion, HBV may promote viral persistence in CHB patients by inhibiting C2 expression.

Large-scale genome-wide association study identifies HLA class II variants associated with chronic HBV infection: a study from Taiwan Biobank

BACKGROUND

Chronic hepatitis B virus (HBV) infection is a great health burden with geographical variations.

AIMS

To explore genetic variants associated with chronic HBV infection.

METHODS

The study included 15 352 participants seropositive for HBV core antibodies in Taiwan Biobank. Among them, 2591 (16.9%) seropositive for HBV surface antigen (HBsAg) were defined as having chronic HBV infection. All participants were examined for whole-genome genotyping by Axiom-Taiwan Biobank Array. The human leucocyte antigen (HLA) imputation was performed after identification of the variants within the region. Logistic regressions were used to estimate odds ratios (ORs) with 95% confidence intervals. Correlations of different HLA allele frequencies with HBsAg seroprevalence were evaluated across worldwide populations by Pearson correlation coefficients. Epitope prediction was performed for HLA alleles using NetMHCIIpan method.

RESULTS

Located within a cluster of 450 single nucleotide polymorphisms in HLA class II, rs7770370 (P = 2.73 × 10^-35 ) was significantly associated with HBV chronicity (P_corrected  < 8.6 × 10^-8 ). Imputation analyses showed that HLA-DPA1*02:02 and HLA-DPB1*05:01 were associated with chronic HBV, with adjusted ORs of 1.43 (1.09-1.89) and 1.61 (1.29-2.01). These allele frequencies were positively correlated with global HBsAg seroprevalence, with R of 0.75 and 0.62 respectively (P < 0.05). HLA-DRB1*13:02, HLA-DQA1* 01:02 and HLA-DQB1*06:09 associated with HBV chronicity negatively, with adjusted ORs of 0.31 (0.17-0.58), 0.70 (0.56-0.87) and 0.33 (0.18-0.63). These HLA alleles had various binding affinities to the predicted epitopes derived from HBV nucleocapsid protein.

CONCLUSIONS

HLA class II variants are relevant for chronicity after HBV acquisition.

Factors associated with clearance of hepatitis B virus surface antigen in patients infected with human immunodeficiency virus

Owing to similar routes of transmission, hepatitis B virus (HBV) and human immunodeficiency virus (HIV) coinfection commonly occurs. Compared with patients infected with only HBV, coinfected patients develop persistent HBV infection followed by advanced liver diseases. However, the characteristics of HIV-infected patients who can achieve the clearance of HBV surface antigen (HBsAg) have not been clarified. In this study, we retrospectively examined patients coinfected with HBV and HIV and determined the host factors associated with HBsAg clearance.Among HIV-infected patients who visited our hospital between 1994 and 2017, we examined medical records of those who were seropositive for HBsAg at least once. Among them, patients who cleared HBsAg afterward were regarded as "cured," while those who remained HBsAg-seropositive until 2017 were "chronic."HBsAg seropositivity was found in 57 patients, and among them, 27 male patients were cured whereas 18 were chronic. The cured patients were significantly younger and had higher CD4 cell and platelet counts than the chronic patients. In addition, the cured patients had higher levels of transaminases after the detection of HBsAg. Multivariate analysis revealed age as an independent factor. Analyses of the patients infected with genotype A also showed that the cured patients had significantly higher CD4 cell counts.Considering that the CD4 cell and platelet counts were higher in the cured patients, immunological and liver functions were closely associated with HBsAg clearance. Higher levels of transaminases in the cured patients may also reflect the immunological function leading to HBsAg clearance.

Genetic variants in class II transactivator are associated with chronic hepatitis B virus infection in the Han Chinese population

Class II transactivator (CIITA) is a master regulator of MHC gene expression and plays a role in inducing the expression of other immune system genes, including IL-4, IL-10 and Fas ligand, as well as more than 60 other immunologically significant genes. We used CIITA as a candidate gene to analyse whether any single-nucleotide polymorphisms (SNPs) are associated with chronic hepatitis B virus (HBV) infection. In total, 773 patients with chronic HBV infection were enrolled in this hospital-based case-control study. The patients were divided into groups according to their clinical characteristics: 596 patients had chronic hepatitis B (CHB), and 177 patients had hepatocellular carcinoma (HCC). A total of 313 patients with self-limited HBV infection were selected as the control group. CIITA gene variants were screened using Haploview 4.2 software; improved multiplex ligation detection reaction technology was then used for genotype detection, and HaploReg v4.1 was employed to predict the functions of 15 variants. The results showed that SNPs in introns in the CIITA gene, namely, rs13333382 (TT + TA vs. AA: p = .003, odds ratio (OR) = 0.65, 95% confidence interval (CI) = 0.49-0.87) and rs4780335 (CC + CG vs. GG: p = 9.40 × 10^-5 , OR = 0.55, 95% CI = 0.41-0.74), were positively associated with self-limited HBV infection in the dominant genetic model. Additionally, SNP rs1139564 (TT + TC vs. CC: p = .002, OR = 1.61, 95% CI = 1.19-2.16) in the 3' untranslated region may increase the risk of CHB. According to in silico analysis, all three statistically significant variants act as transcription factor binding motifs. However, we did not find that these 15 mutations are associated with HCC risk. Therefore, we believe that CIITA is a susceptibility gene for CHB rather than for HCC.

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.

HLA-DQB1/DRB1 Alleles Associate with Traditional Chinese Medicine Syndrome of Chronic Hepatitis B: A Potential Predictor of Progression

Background and Aims

Traditional Chinese medicine (TCM) has been widely applied in chronic hepatitis B (CHB) supplementary treatment in China. Kidney yang deficiency syndrome (KYDS), one of the most common TCM syndromes of CHB, is more likely to progress to liver cirrhosis or hepatocellular carcinoma than other syndromes. Polymorphisms in the human leucocyte antigen- (HLA-) DQB1 and -DRB1 genes were reported to be associated with hepatitis B virus infection outcomes. Here, we investigated whether HLA-DQB1 and HLA-DRB1 are associated with the classification of CHB TCM syndromes.

Methods

We genotyped HLA-DQB1 and HLA-DRB1 alleles in a total of 105 subjects, including 74 CHB patients (28 KYDS and 46 non-KYDS) and 31 healthy individuals from Sichuan Province of Southwest China, by polymerase chain reaction sequence-based typing (PCR-SBT). Moreover, a meta-analysis was carried out for further verification.

Results

The proportion of patients with high HBV DNA load (≥2000 IU/ml) in the KYDS group is higher than that in the non-KYDS group (60.70% [17/28] vs. 28.30% [13/46]); P=0.01). The frequencies of HLA-DQB1∗02:01 (P=0.04) and HLA-DRB1∗03:01 (P=0.04) in the KYDS group were significantly increased compared to the non-KYDS group. The gene test and meta-analysis showed that HLA-DRB1∗08:03 confers susceptibility to CHB (odds ratio = 1.57).

Conclusion

We found an association between HLA-DRB1/DQB1 polymorphisms and KYDS of CHB. Moreover, KYDS patients of CHB are characteristic with high HBV DNA loads. These findings help to reveal the biological mechanism of KYDS in high risk of CHB progression and suggest a potential prognostic value for disease outcome evaluation.

GWAS identifying HLA-DPB1 gene variants associated with responsiveness to hepatitis B virus vaccination in Koreans: Independent association of HLA-DPB1*04:02 possessing rs1042169 G - rs9277355 C - rs9277356 A

Recently, HLA class II loci, including HLA-DPB1, have been reported to be associated with interindividual variance in the hepatitis B (HB) vaccine response. In this study, we investigated significant single nucleotide polymorphisms (SNPs) for anti-HBs antibody levels in 6867 healthy Koreans using a genome-wide association study (GWAS). In GWAS, the top 20 SNPs that showed significant association with anti-HBs levels (P < 1.0 × 10^-29 ) all resided in HLA-DPB1. Utilizing PCR sequencing, we verified the relationship of the top 3 most significant SNPs (rs1042169, rs9277355 and rs9277356) from the GWAS and genotypes of HLA-DPB1 with the HB vaccine response in Korean infants who received a scheduled vaccination. The DPB1*04:02 allele has G, C and A nucleotides for the 3SNP sites, and was significantly more frequent in responders than in nonresponders (10.9% vs 1.0%, P_c  = 0.018). DPB1*05:01 was significantly more frequent in nonresponders than in responders (49.0% vs 31.1%, P_c  = 0.018). In multivariate logistic regression, DPB1*04:02 showed a significant association with both vaccine response (P = 0.037, OR = 8.465) and high-titre response (P = 0.027, OR = 9.860). The haplotypes rs1042169 G - rs9277355 C - rs9277356 A showed a significant association with a high-titre response only (P = 0.002, OR = 2.941). In conclusion, DPB1*04:02 possessing rs1042169 G - rs9277355 C - rs9277356 A is an independent predictor of the HB vaccine response in Koreans.

Response to hepatitis B vaccination is co-determined by HLA-DPA1 and -DPB1

BACKGROUND AND AIMS

No report explored the combined effects of HLA-DPA1 and -DPB1 with long-term response to hepatitis B (HB) vaccination (HBVac). The specific aims of the study were to assess the combined effects and relative contributions of DPA1 and DPB1 genes.

METHODS

The cases were 152 adolescents who had undetectable (<1.0 mIU/mL) post-booster anti-HBs titers and the controls were adolescents who had residual anti-HBs ≥ 10 mIU/mL at aged 16 years (n = 207) or had detectable (≥1.0 mIU/mL) anti-HBs titers after booster HBVac (n = 481). HLA-DPA1 and -DPB1 genotypes were determined by sequence-based typing.

RESULTS

HLA-DPA1*01:03:01 was correlated with lower ORs of undetectable anti-HBs titers, while -DPA1*02:02:02 and -DPB1*05:01:01 were correlated with higher ORs. The ORs for HLA-DPA1*01:03:01-DPB1*05:01:01 and DPA1*02:02:02-DPB1*protective combinatory types were significantly less than 1.0. As compared with subjects who had no protective allele, the adjusted ORs (95% CI) were 0.545 (0.328-0.906), 0.350 (0.174-0.702), and 0.122 (0.058-0.257), for subjects who had protective alleles on DPA1only, DPB1 only, and both genes, respectively. Analyses of amino acid polymorphisms showed that subjects who carried Arg81-Pro158-Val191-Pro259α + Met234β and Gln62-Arg82α + Met234β combinations had 4.3-to-4.6 folds of risks.

CONCLUSION

Both DPA1 and DPB1 genes contribute to the persistence of immunological response to primary infantile HBVac. The effects of HLA-DP risk alleles were dominated by the protective alleles and there were significant gene-gene interactions. Our findings provide evidences for the design of more potent HB vaccine.

Genetic variation in FCER1A predicts peginterferon alfa-2a-induced hepatitis B surface antigen clearance in East Asian patients with chronic hepatitis B

In a multicentre, genome-wide association study to identify host genetic factors associated with treatment response in adult chronic hepatitis B patients, genotype data were obtained by microarray analysis from 1669 patients who received peginterferon alfa-2a for ≥ 24 weeks with/without a nucleos(t)ide analog. Treatment response was assessed at least 24 weeks post-treatment, using serological and/or virological endpoints. Thirty-six single-marker analyses and a gene-by-gene analysis were conducted. No single nucleotide polymorphisms (SNPs) achieved genome-wide significance (P < 5 × 10^-8 ) in single-marker analyses, but suggestive associations (P < 1 × 10^-5 ) were identified for 116 SNPs. In gene-by-gene analyses, one gene, FCER1A (rs7549785), reached genome-wide significance (P = 2.65 × 10^-8 ) in East Asian patients for hepatitis B surface antigen (HBsAg) clearance, with a moderate effect size (odds ratio = 4.74). Eleven of 44 carriers (25%) of the A allele at rs7549785 achieved HBsAg clearance compared with 69/1051 (7%) noncarriers. FCER1A encodes the alpha subunit of the immunoglobulin E receptor. In a post hoc analysis of a homogenous patient subset, the strongest intragenic association was for rs7712322 (POLR3G, P = 7.21 × 10^-7 ). POLR3G encodes the G subunit of the polymerase (RNA) III enzyme, involved in sensing and limiting infection by intracellular bacteria and DNA viruses, and as a DNA sensor in innate immune responses. FCER1A (rs7549785) and possibly POLR3G (rs7712322) are shown to be associated with peginterferon alfa-2a response in adult patients with chronic hepatitis B. Independent confirmation of these findings is warranted (clinicaltrials.gov number NCT01855997).

Host Genetic Determinants of Hepatitis B Virus Infection

Chronic hepatitis B virus (HBV) infection is still a major health problem worldwide. Recently, a great number of genetic studies based on single nucleotide polymorphisms (SNPs) and genome-wide association studies have been performed to search for host determinants of the development of chronic HBV infection, clinical outcomes, therapeutic efficacy, and responses to hepatitis B vaccines, with a focus on human leukocyte antigens (HLA), cytokine genes, and toll-like receptors. In addition to SNPs, gene insertions/deletions and copy number variants are associated with infection. However, conflicting results have been obtained. In the present review, we summarize the current state of research on host genetic factors and chronic HBV infection, its clinical type, therapies, and hepatitis B vaccine responses and classify published results according to their reliability. The potential roles of host genetic determinants of chronic HBV infection identified in these studies and their clinical significance are discussed. In particular, HLAs were relevant for HBV infection and pathogenesis. Finally, we highlight the need for additional studies with large sample sizes, well-matched study designs, appropriate statistical methods, and validation in multiple populations to improve the treatment of HBV infection.

A Functional Variant in Ubiquitin Conjugating Enzyme E2 L3 Contributes to Hepatitis B Virus Infection and Maintains Covalently Closed Circular DNA Stability by Inducing Degradation of Apolipoprotein B mRNA Editing Enzyme Catalytic Subunit 3A

Hepatitis B virus (HBV) infection is a common infectious disease, in which nuclear covalently closed circular DNA (cccDNA) plays a key role in viral persistence, viral reactivation after treatment withdrawal, and drug resistance. A recent genome-wide association study has identified that the ubiquitin conjugating enzyme E2 L3 (UBE2L3) gene is associated with increased susceptibility to chronic HBV (CHB) infection in adults. However, the association between UBE2L3 and children with CHB and the underlying mechanism remain unclear. In this study, we performed two-stage case-control studies including adults and independent children in the Chinese Han population. The rs59391722 allele in the promoter of the UBE2L3 gene was significantly associated with HBV infection in both adults and children, and it increased the promoter activity of UBE2L3. Serum UBE2L3 protein levels were positively correlated with HBV viral load and hepatitis B e antigen (HBeAg) levels in children with CHB. In an HBV infection cell model, UBE2L3 knockdown significantly reduced total HBV RNAs, 3.5-kb RNA, as well as cccDNA in HBV-infected HepG2-Na+ /taurocholate cotransporting polypeptide cells and human primary hepatocytes. A mechanistic study found that UBE2L3 maintained cccDNA stability by inducing proteasome-dependent degradation of apolipoprotein B mRNA editing enzyme catalytic subunit 3A, which is responsible for the degradation of HBV cccDNA. Moreover, interferon-α (IFN-α) treatment markedly decreased UBE2L3 expression, while UBE2L3 silencing reinforced the antiviral activity of IFN-α on HBV RNAs, cccDNA, and DNA. rs59391722 in UBE2L3 was correlated with HBV DNA suppression and HBeAg loss in response to IFN-α treatment of children with CHB. Conclusion: These findings highlight a host gene, UBE2L3, contributing to the susceptibility to persistent HBV infection; UBE2L3 may be involved in IFN-mediated viral suppression and serve as a potential target in the prevention and treatment of HBV infection.

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.

Genetic Factors That Affect Spontaneous Clearance of Hepatitis C or B Virus, Response to Treatment, and Disease Progression

Hepatitis C virus (HCV) and hepatitis B virus (HBV) infections can lead to cirrhosis, end-stage liver disease, and hepatocellular carcinoma. Over the past decade, studies of individuals infected with these viruses have established genetic associations with the probability of developing a chronic infection, risk of disease progression, and likelihood of treatment response. We review genetic and genomic methods that have been used to study risk of HBV and HCV infection and patient outcomes. For example, genome-wide association studies have linked a region containing the interferon lambda genes to spontaneous and treatment-induced clearance of HCV. We review the genetic variants associated with HCV and HBV infection, and how these variants affect specific expression or activities of their products. Further studies of these variants could provide insights into risk factors for and mechanisms of chronic infection and disease progression, as well as new strategies for treatment.

Interleukin-6 gene variants are associated with reduced risk of chronicity in hepatitis B virus infection in a Malaysian population

Interleukin-6 (IL-6) is a cytokine with a critical role in regulating the immune response to infectious disease. Studies have indicated that polymorphisms in the IL-6 gene may be linked to hepatitis B virus (HBV) infection. The purpose of the present study was to examine the association among IL-6 SNPs and haplotypes with HBV infection risk in a Malaysian population. A total of 1,246 Malaysian subjects with and without chronic hepatitis B were recruited for this study. Three IL-6 polymorphisms (rs2069837, rs1800796 and rs2066992) were genotyped using a Sequenom MassARRAY^® platform. The results suggested that GC and CC genotypes of rs1800796 as well as GT and TT genotypes of rs2066992 were associated with protection against HBV infection (P<0.001). Furthermore, haplotypes GG and CT exhibited a significant association with protection against HBV (P=0.003 and =0.005, respectively); and haplotypes GG and CT exhibited a significant association with clearance of HBV infection (P=0.035 and =0.037, respectively). The present study indicates that two IL-6 SNPs (rs1800796 and rs2066992) are associated with clearance of chronic HBV or protection against HBV infection at allelic, genotypic and haplotypic levels.

Genetic association of complement component 2 variants with chronic hepatitis B in a Korean population

BACKGROUND & AIMS

Numerous single nucleotide polymorphisms associated with an increased risk of liver diseases, chronic hepatitis B and chronic hepatitis B-related hepatocellular carcinoma have been identified. In this study, we scrutinized the genetic effects of C2 variants, which were conflicting in previous results, on the risk of chronic hepatitis B in a Korean population.

METHODS

We genotyped 22 common C2 genetic variants of 977 chronic hepatitis B cases including 302 chronic hepatitis B-related hepatocellular carcinoma cases and 785 population controls. Statistical analysis was performed to examine the effects of genotype on the risk of chronic hepatitis B and chronic hepatitis B-related hepatocellular carcinoma.

RESULTS

Logistic regression analyses showed that six C2 single nucleotide polymorphisms had significant associations with the risk of chronic hepatitis B and chronic hepatitis B-related hepatocellular carcinoma among the Korean subjects. Stepwise analysis revealed that causal markers (rs9267665 and rs10947223) were identified among the C2 variants (stepwise P = 3.32 × 10^-9 and 2.04 × 10^-5 respectively). In further conditional analysis with previous chronic hepatitis B-associated loci, these two single nucleotide polymorphisms were independently associated with the risk of chronic hepatitis B. In addition, we investigated the ability of genetic risk scores combining 12 multi-chronic hepatitis B loci to predict the risk of chronic hepatitis B. Individuals with higher genetic risk scores showed increased risk for chronic hepatitis B.

CONCLUSIONS

Our results suggested that the C2 gene might be a susceptibility locus for chronic hepatitis B in Korean populations. The cumulative genetic effects may contribute to future etiological explanations for chronic hepatitis B.

Key HLA-DRB1-DQB1 haplotypes and role of the BTNL2 gene for response to a hepatitis B vaccine

Approximately 5-10% of individuals who are vaccinated with a hepatitis B (HB) vaccine designed based on the hepatitis B virus (HBV) genotype C fail to acquire protective levels of antibodies. Here, host genetic factors behind low immune response to this HB vaccine were investigated by a genome-wide association study (GWAS) and Human Leukocyte Antigen (HLA) association tests. The GWAS and HLA association tests were carried out using a total of 1,193 Japanese individuals including 107 low responders, 351 intermediate responders, and 735 high responders. Classical HLA class II alleles were statistically imputed using the genome-wide SNP typing data. The GWAS identified independent associations of HLA-DRB1-DQB1, HLA-DPB1 and BTNL2 genes with immune response to a HB vaccine designed based on the HBV genotype C. Five HLA-DRB1-DQB1 haplotypes and two DPB1 alleles showed significant associations with response to the HB vaccine in a comparison of three groups of 1,193 HB vaccinated individuals. When frequencies of DRB1-DQB1 haplotypes and DPB1 alleles were compared between low immune responders and HBV patients, significant associations were identified for three DRB1-DQB1 haplotypes, and no association was identified for any of the DPB1 alleles. In contrast, no association was identified for DRB1-DQB1 haplotypes and DPB1 alleles in a comparison between high immune responders and healthy individuals. Conclusion: The findings in this study clearly show the importance of HLA-DR-DQ (i.e., recognition of a vaccine related HB surface antigen (HBsAg) by specific DR-DQ haplotypes) and BTNL2 molecules (i.e., high immune response to HB vaccine) for response to a HB vaccine designed based on the HBV genotype C. (Hepatology 2018).

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.

A cis-eQTL of HLA-DPB1 Affects Susceptibility to Type 1 Autoimmune Hepatitis

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease characterized by an autoimmune reaction to hepatocytes. A single nucleotide polymorphism in the 3′ untranslated region of HLA-DPB1, rs9277534, is associated with HLA-DPB1 expression. rs9277534 has been linked to hepatitis B virus recovery/persistence and the risk of graft-versus-host disease with HLA-DPB1 mismatching transplantation of hematopoietic cells, but its role along with that of HLA-DP expression in AIH have not been fully clarified. We genotyped rs9277534 in 146 Japanese patients with AIH and 326 healthy subjects. HLA-DPB1 expression was determined by quantitative PCR. HLA-DPB1 expression was significantly higher for rs9277534G than for rs9277534A (P < 0.05). rs9277534 genotype was in strong linkage disequilibrium with the HLA-DPB1 allele (pairwise D′ = 0.82–1.00). Although HLA-DP alleles were not significantly associated with AIH, the frequency of the rs9277534G allele was significantly higher in AIH patients compared with healthy subjects (P = 0.002, odds ratio [OR] = 1.56). Logistic regression analysis revealed that the HLA-DRB1*04:05 allele (P < 0.001, OR = 4.61) and rs9277534 (P = 0.004, OR = 1.67) were independently associated with AIH susceptibility. rs9277534G in the HLA-DP gene is an eQTL that affects gene expression and may contribute to AIH susceptibility.

Human leukocyte antigen gene polymorphisms are associated with systemic inflammation in hepatitis B virus-related hepatocellular carcinoma

Background

Systemic inflammation (SI) is associated with tumor progression and overall survival (OS) in patients with hepatocellular carcinoma (HCC). The presence of some single nucleotide polymorphisms (SNPs) in the human leukocyte antigen (HLA) region can influence the prognosis of patients with hepatitis B virus (HBV)-related HCC, although the mechanism remains unknown. This study aimed to analyze the correlations between HLA gene polymorphisms and SI.

Patients and methods

This study included 330 patients with HCC. The clinical parameters were reviewed, and five SNPs, namely rs2647073, rs3997872, rs3077, rs7453920, and rs7768538, were genotyped using the MassARRAY system.

Results

The rs3997872, rs7453920, and rs7768538 genotypes were found to be significantly associated with OS (P<0.05). The rs7453920 genotype was significantly associated with the neutrophil/lymphocyte ratio (NLR; P=0.001), which was used as an SI index with a threshold determined by receiver operating characteristic analysis. An elevated NLR was also an independent predictor of OS according to univariate and multivariate analyses (P<0.001).

Conclusion

Our data show that HLA gene polymorphisms are associated with SI in patients with HBV-related HCC, and the absence of minor allele A (rs7453920) promotes SI and shortens OS.

Identification of novel susceptibility loci associated with hepatitis B surface antigen seroclearance in chronic hepatitis B

BACKGROUND/AIMS

The seroclearance of hepatitis B virus (HBV) surface antigen (HBsAg) is regarded as a functional cure of chronic hepatitis B (CHB) although it occurs rarely. Recently, several genome-wide association studies (GWASs) revealed various genetic alterations related to the clinical course of HBV infection. However, all of these studies focused on the progression of HBV infection to chronicity and had limited application because of the heterogeneity of HBV genotypes. In the present study, we aimed to determine susceptibility genetic markers for seroclearance of HBsAg in CHB patients with a homogenous viral genotype.

METHODS

One hundred patients with CHB who had experienced HBsAg seroclearance before 60 years of age and another 100 with CHB showing high serum levels of HBsAg even after 60 years of age were enrolled. Extreme-phenotype GWAS was conducted using blood samples of participants.

RESULTS

We identified three single nucleotide polymorphisms, rs7944135 (P = 4.17 × 10-6, odds ratio [OR] = 4.16, 95% confidence interval [CI] = 2.27-7.63) at 11q12.1, rs171941 (P = 3.52×10-6, OR = 3.69, 95% CI = 2.13-6.42) at 5q14.1, and rs6462008 (P = 3.40×10-6, OR = 0.34, 95% CI = 0.22-0.54) at 7p15.2 as novel susceptibility loci associated with HBsAg seroclearance in patients with CHB. The flanking genes at these loci including MPEG1, DTX4, MTX3, and HOXA13 were suggested to have functional significance. In addition, through functional analysis, CXCL13 was also presumed to be related.

CONCLUSIONS

To the best of our knowledge, this study is the first GWAS regarding the seroclearance of HBsAg in CHB patients. We identify new susceptibility loci for cure of CHB, providing new insights into its pathophysiology.

Genetic polymorphism and decreased expression of HLA class II DP genes are associated with HBV reactivation in patients treated with immunomodulatory agents

Hepatitis B virus (HBV) reactivation can be triggered by immunosuppressive chemotherapy. HLA class II molecules may play a role in HBV reactivation. Genetic polymorphism and mRNA expression of HLA class II were examined in patients with latent HBV infection treated with immunosuppressive therapies. Subjects with resolved HBV infection who had undergone treatment with immunosuppressive chemotherapies were retrospectively enrolled (n = 42) and divided into reactivated (n = 9) and non-reactivated groups (n = 33). Patients were genotyped for 17 single nucleotide polymorphisms (SNPs) within HLA class II DPA1, and DPB1, and mRNA expression levels of HLA class II genes were assessed. The frequency of the AA genotype of rs872956, a SNP in HLA-DPB1, was significantly higher in the reactivated group than in the non-reactivated group (55.6% vs 12.1%, P < 0.05). The frequencies of the T allele and non-AA genotypes (AT/TT) of rs3116996 (located in DPB1) were significantly higher in the reactivated group (T allele frequency: 16.7% vs 0.0% [P < 0.01], non-AA genotype frequency: 22.2% vs 0.0% [P < 0.05]). Multivariate logistic regression identified the AA genotype of rs872956 as an independent protective factor against HBV reactivation (odds ratio [OR] = 18.1, 95% confidence interval [CI] = 2.6-126.7, P < 0.01). mRNA expression of HLA-DPB1 was lower in the HBV reactivated group than in the non-reactivated group (median 276.1 ± 165.6/β-actin vs 371.4 ± 407.5/β-actin [P < 0.05]). These results suggest the involvement of HLA class II molecules in HBV reactivation after treatment with immunomodulatory agents.

Virological and Clinical Characteristics of Hepatitis B Virus Genotype A

Hepatitis B virus (HBV) infection is one of the most prevalent chronic viral infections in humans. The overall prevalence of hepatitis B surface antigen (HBsAg) is reported to be 3.6%; however, it varies depending upon the geographic area. HBV is classified into ten genotypes (A through J) on the basis of an intergroup genomic divergence of > 8%. Specifically, HBV genotype A exhibits several unique virological and clinical characteristics and can be further classified into seven subtypes. Among them, subtype A2 or Ae (A2/[e]) is occasionally responsible for nosocomial infection and among homosexual males. Regarding virological factors, the G1896A precore mutation is rarely observed in genotype A as it would disrupt an essential stem-loop structure in the ε signal essential for pregenomic RNA packaging. HBV genotype A also harbors a 6-nucleotide C-terminal insertion in the hepatitis B-e antigen (HBeAg) precursor, resulting in a variable-length HBeAg protein product observed in serum of positive patients. These molecular traits likely contribute to the specific clinical presentation of genotype A-infected patients, such as mild acute hepatitis B (AHB), longer persistence of HBsAg positivity in AHB, and increased chronicity after AHB in adults. However, genotype A shows a better response to interferon than other genotypes in chronic hepatitis B patients. Here, we review the virological and clinical characteristics of HBV genotype A that will be useful in elucidating the association among persistent viral infection, host genetic factors, and treatment in future studies.

Advances in the genome-wide association study of chronic hepatitis B susceptibility in Asian population

Chronic hepatitis B (CHB) is the most common chronic liver disease resulting from viral infection and has become a serious threat to human health. Each year, about 1.2 million people in the world die from diseases caused by chronic infection of hepatitis B virus. The genetic polymorphism is significantly associated with the susceptibility to chronic hepatitis B. Genome-wide association study was recently developed and has become an important tool to detect susceptibility genes of CHB. To date, a number of CHB-associated susceptibility loci and regions have been identified by scientists over the world. To clearly understand the role of susceptibility loci in the occurrence of CHB is important for the early diagnosis and prevention of CHB.

Single nucleotide polymorphisms in ZNF208 are associated with increased risk for HBV in Chinese people

Single nucleotide polymorphisms (SNPs) in ZNF208 may be associated with susceptibility to Hepatitis B virus (HBV). In the current study, we analyzed the association between ZNF208 SNPs and risk of HBV in 242 HBV patients and 300 healthy subjects from the Xi'an area of Chinese Han Population. Of the five SNPs examined, rs2188971 (OR: 1.36, 95% CI: 1.04-1.76, P = 0.022), rs8103163 (OR: 1.40, 95% CI: 1.08-1.82, P = 0.010) and rs7248488 (OR: 1.38, 95% CI: 1.07-1.79, P = 0.014) were correlated with HBV susceptibility based on Chi-square tests. After the P-values were adjusted by Bonferroni correction, there only rs8103163 (P = 0.050) was slightly with increased HBV risk. Additionally, haplotype A_rs2188972T_rs2188971A_rs8103163A_rs7248488 (OR = 1.42; 95% C I, 1.10-1.85; P = 0.008) was found to increase susceptibility of suffering from HBV. These findings suggest that ZNF208 polymorphisms may contribute to the development of HBV.

Quantitative assessment of HLA-DQ gene polymorphisms with the development of hepatitis B virus infection, clearance, liver cirrhosis, and hepatocellular carcinoma

Hepatitis B is one of the most common infectious diseases, which leads to public health problems in the world, especially in Asian counties. In recent years, extensive human genetic association studies have been carried out to identify susceptible genes and genetic polymorphisms to understand the genetic contributions to the disease progression of HBV infection. HLA-DQ gene variations have been reported to be associated with HBV infection/clearance, disease progression and the development of hepatitis B-related complications, including liver cirrhosis (LC) and hepatocellular carcinoma (HCC). However, the results are either inconclusive or controversial. Therefore, to derive a more precise estimation of the association, a meta-analysis was performed. Our data revealed that the HLA-DQ alleles rs2856718-G, rs7453920-A and rs9275319-G were significantly associated with decreased risk of HBV infection and HBV natural clearance. Logistic regression analyses showed that HLA-DQ alleles rs9275572-A significantly increased HBV infection clearance, and decreased HBV natural clearance. However, rs2856718-G and rs9275572-A were not associated with development of cirrhosis. The HLA-DQ polymorphisms (rs2856718 and rs9275572) were associated with a decreased HBV-related HCC risk in all genetic models, but rs9272105-A increased the risk of HBV-related HCC. In addition, no significant association was observed between HLA-DQ rs9275319-G polymorphism and HBV-related HCC. These stratified analyses were limited due to relatively modest size of correlational studies. In future, further investigation on a large population and different ethnicities are warranted. Our findings contribute to the personalized care and prognosis in hepatitis B.

A global perspective on hepatitis B-related single nucleotide polymorphisms and evolution during human migration

Genome-wide association studies have indicated that human leukocyte antigen (HLA)-DP and HLA-DQ play roles in persistent hepatitis B virus (HBV) infection in Asia. To understand the evolution of HBV-related single nucleotide polymorphisms (SNPs) and to correlate these SNPs with chronic HBV infection among different populations, we conducted a global perspective study on hepatitis-related SNPs. We selected 12 HBV-related SNPs on the HLA locus and two HBV and three hepatitis C virus immune-related SNPs for analysis. Five nasopharyngeal carcinoma-related SNPs served as controls. All SNP data worldwide from 26 populations were downloaded from 1,000 genomes. We found a dramatic difference in the allele frequency in most of the HBV- and HLA-related SNPs in East Asia compared to the other continents. A sharp change in allele frequency in 8 of 12 SNPs was found between Bengali populations in Bangladesh and Chinese Dai populations in Xishuangbanna, China (P < 0.001); these areas represent the junction of South and East Asia. For the immune-related SNPs, significant changes were found after leaving Africa. Most of these genes shifted from higher expression genotypes in Africa to lower expression genotypes in either Europe or South Asia (P < 0.001). During this two-stage adaptation, immunity adjusted toward a weak immune response, which could have been a survival strategy during human migration to East Asia. The prevalence of chronic HBV infection in Africa is as high as in Asia; however, the HBV-related SNP genotypes are not present in Africa, and so the genetic mechanism of chronic HBV infection in Africa needs further exploration. Conclusion: Two stages of genetic changes toward a weak immune response occurred when humans migrated out of Africa. These changes could be a survival strategy for avoiding cytokine storms and surviving in new environments. (Hepatology Communications 2017;1:1005-1013).

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.

Genetic susceptibility to infectious diseases: Current status and future perspectives from genome-wide approaches

Genome-wide association studies (GWASs) have been widely applied to identify genetic factors that affect complex diseases or traits. Presently, the GWAS Catalog includes > 2800 human studies. Of these, only a minority have investigated the susceptibility to infectious diseases or the response to therapies for the treatment or prevention of infections. Despite their limited application in the field, GWASs have provided valuable insights by pinpointing associations to both innate and adaptive immune response loci, as well as novel unexpected risk factors for infection susceptibility. Herein, we discuss some issues and caveats of GWASs for infectious diseases, we review the most recent findings ensuing from these studies, and we provide a brief summary of selected GWASs for infections in non-human mammals. We conclude that, although the general trend in the field of complex traits is to shift from GWAS to next-generation sequencing, important knowledge on infectious disease-related traits can be still gained by GWASs, especially for those conditions that have never been investigated using this approach. We suggest that future studies will benefit from the leveraging of information from the host's and pathogen's genomes, as well as from the exploration of models that incorporate heterogeneity across populations and phenotypes. Interactions within HLA genes or among HLA variants and polymorphisms located outside the major histocompatibility complex may also play an important role in shaping the susceptibility and response to invading pathogens.

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Relatively few GWASs for infectious diseases were performed.

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Phenotype heterogeneity and case/control misclassification can affect GWAS power.

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Adaptive and innate immunity loci were identified in several infectious disease GWASs.

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Unexpected loci (e.g., lncRNAs) were also associated with infection susceptibility.

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GWASs should integrate host and pathogen diversity and use complex association models.

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.

A human PSMB11 variant affects thymoproteasome processing and CD8+ T cell production

The Psmb11-encoded β5t subunit of the thymoproteasome, which is specifically expressed in cortical thymic epithelial cells (cTECs), is essential for the optimal positive selection of functionally competent CD8+ T cells in mice. Here, we report that a human genomic PSMB11 variation, which is detectable at an appreciable allele frequency in human populations, alters the β5t amino acid sequence that affects the processing of catalytically active β5t proteins. The introduction of this variation in the mouse genome revealed that the heterozygotes showed reduced β5t expression in cTECs and the homozygotes further exhibited reduction in the cellularity of CD8+ T cells. No severe health problems were noticed in many heterozygous and 5 homozygous human individuals. Long-term analysis of health status, particularly in the homozygotes, is expected to improve our understanding of the role of the thymoproteasome-dependent positive selection of CD8+ T cells in humans.

Adaptive evolution of proteins in hepatitis B virus during divergence of genotypes

Hepatitis B virus (HBV) is classified into several genotypes, correlated with different geographic distributions, clinical outcomes and susceptible human populations. It is crucial to investigate the evolutionary significance behind the diversification of HBV genotypes, because it improves our understanding of their pathological differences and pathogen-host interactions. Here, we performed comprehensive analysis of HBV genome sequences collected from public database. With a stringent criteria, we generated a dataset of 2992 HBV genomes from eight major genotypes. In particular, we applied a specified classification of non-synonymous and synonymous variants in overlapping regions, to distinguish joint and independent gene evolutions. We confirmed the presence of selective constraints over non-synonymous variants in consideration of overlapping regions. We then performed the McDonald-Kreitman test and revealed adaptive evolutions of non-synonymous variants during genotypic differentiation. Remarkably, we identified strong positive selection that drove the differentiation of PreS1 domain, which is an essential regulator involved in viral transmission. Our study presents novel evidences for the adaptive evolution of HBV genotypes, which suggests that these viruses evolve directionally for maintenance or improvement of successful infections.

Identification of novel variants in HLA class II region related to HLA DPB1 expression and disease progression in patients with chronic hepatitis C

Recent genome-wide studies have demonstrated that HLA class II gene may play an important role in viral hepatitis. We studied genetic polymorphism and RNA expression of HLA class II genes in HCV-related liver diseases. The study was performed in groups consisting of 24 patients with HCV-related liver disease (12 of persistent normal ALT: PNALT group and 12 of advanced liver disease: ALD group) and 26 patients without HCV infection (control group). In PBMC samples, RNA expression of HLA class II genes (HLA-DPA1, DPB1, DQA1, DQB1, and DRB1) was analyzed by real-time RT-PCR. Furthermore, 22 single nucleotide polymorphisms (SNPs) in HLA class II gene and two SNPs in IL28B gene were genotyped by genetic analyzer (GENECUBE®). In expression analysis, only DPB1 level was significantly different. Mean expression level of DPB1gene in control group was 160.0, PNALT group 233.8, and ALD group 465.0 (P < 0.01). Of 24 SNPs, allele frequencies were statistically different in two SNPs (rs2071025 and rs3116996) between PNALT groups and ALD group (P < 0.01). In rs2071025, TT genotype was frequently detected in ALD group and expression level was significantly higher than the other genotypes (449.2 vs 312.9, P < 0.01). In rs3116996, TA or TT (non AA) genotype was frequently detected in ALD group and expression level was significantly higher than genotype AA (457.1 vs 220.9, P < 0.01). Genotyping and expression analysis in HLA class II gene revealed that two SNPs of HLA-DPB1 (rs2071025 and rs3116996) were significantly correlated to RNA expression and progression of HCV-related liver diseases.

The MHC locus and genetic susceptibility to autoimmune and infectious diseases

In the past 50 years, variants in the major histocompatibility complex (MHC) locus, also known as the human leukocyte antigen (HLA), have been reported as major risk factors for complex diseases. Recent advances, including large genetic screens, imputation, and analyses of non-additive and epistatic effects, have contributed to a better understanding of the shared and specific roles of MHC variants in different diseases. We review these advances and discuss the relationships between MHC variants involved in autoimmune and infectious diseases. Further work in this area will help to distinguish between alternative hypotheses for the role of pathogens in autoimmune disease development.

The MHC locus and genetic susceptibility to autoimmune and infectious diseases

In the past 50 years, variants in the major histocompatibility complex (MHC) locus, also known as the human leukocyte antigen (HLA), have been reported as major risk factors for complex diseases. Recent advances, including large genetic screens, imputation, and analyses of non-additive and epistatic effects, have contributed to a better understanding of the shared and specific roles of MHC variants in different diseases. We review these advances and discuss the relationships between MHC variants involved in autoimmune and infectious diseases. Further work in this area will help to distinguish between alternative hypotheses for the role of pathogens in autoimmune disease development.