Host susceptibility to persistent hepatitis B virus infection

Prediction Model for the Clearance of Hepatitis B Surface Antigen in Patients with Chronic Hepatitis B before Interferon Therapy: A Prospective Case-Control Study

To evaluate the prediction model comprised of patients' laboratory results and single-nucleotide polymorphism (SNP) markers of host gene for the clearance of hepatitis B surface antigen (HBsAg) in patients with chronic hepatitis B (CHB) who underwent interferon (IFN)-α therapy, this prospective case-control study enrolled 131 patients with CHB who underwent IFN-α-based regimens in our hospital between January 2015 and September 2019. Among them, 56 cases were without HBsAg clearance, while the other 75 cases had HBsAg clearance. Multivariable logistic regression analysis showed that CYP27B1 rs4646536 (odd ratio [OR] = 0.155, 95% CI: 0.030-0.807, p = 0.027), PAK4 rs9676717 (OR = 11.237, 95% CI: 1.768-71.409, p = 0.010), IL28B rs12979860 (OR = 0.059, 95% CI: 0.006-0.604, p = 0.017), baseline HBsAg (OR = 0.170, 95% CI: 0.040-0.716, p = 0.016), and HBeAg status (OR = 3.971, 95% CI: 1.138-13.859, p = 0.031) were independently associated with HBsAg clearance. The model that included rs3077, rs4646536, rs9676717, rs2850015, rs12979860, baseline HBsAg, HBeAg status, and HBV DNA had the best prediction performance for HBsAg clearance prediction, with AUC = 0.877, 80% sensitivity, and 81% specificity. In conclusion, laboratory results and gene polymorphisms before treatment might have a good predictive value for HbsAg clearance after IFN-α treatment in CHB.

The Role of Host in the Spectrum of Outcomes in Family Clusters of Hepatitis Infection: From Asymptomatic to Hepatocellular Carcinoma

Hepatitis B virus infections are prevalent worldwide, but the outcomes of infection vary greatly from host to host. In many endemic regions, vertical transmission from mother to child is most common. In this transmission setting, virus genotype and shared patient genetics make for an interesting comparison of outcome of chronic hepatitis B infection. This case series demonstrates four family clusters which display disparate outcomes among family members with hepatitis B virus infections, further stressing the role of host and non-genetic factors in the natural history of the disease. Many host factors have been theorized, from epigenetic mechanisms to the role of chronic stress, but more research is needed to better understand those at higher risk of feared complications such as hepatocellular carcinoma and cirrhosis.

Association of IRGM gene promoter polymorphisms with Hepatitis B Virus infection

BACKGROUND

In response to intracellular pathogens the autophagy gene IRGM plays an essential role in the innate immune response. Various identified IRGM gene risk loci are associated with several diseases, but so far no study is available which shows the association of IRGM with HBV infection.

METHODS

We genotyped promoter variants (rs4958842, rs4958843, and rs4958846) of IRGM in HBV infected patients (551) and healthy controls (247) for their role in HBV infection. The genotyping was done applying methods developed in our laboratory and various biochemical parameters were assessed applying commercially available kits.

RESULTS

Data analysis has shown that the mutant allele A of rs4958842 plays a role in the protection from HBV infection in various genetic models that includes allelic, co-dominant and dominant models with the respective statistical data (OR=0.61; 95%CI=0.48-0.78; p=0.0003), (OR=0.52; 95%CI=0.38-0.71; p=0.0008) and (OR=0.51; 95%CI=0.38-0.70, p=0.0004). In CHB, protective association was observed in allelic (OR=0.48; 95%CI=0.35-0.65, p=0.0004), co-dominant (OR=0.38; 95%CI=0.26-0.54, p=0.0004) and dominant models (OR=0.38; 95%CI=0.26-0.54, p=0.0002). Mutant allele C of rs49598843 was associated with the risk of CHB in co-dominant (OR=1.52; 95%CI=1.07-2.16, p=0.04) and dominant models (OR=1.41; 95%CI=1.00-2.00, p=0.04). The mutant allele C of rs4958846 decreased the risk of HBV infection in allelic (OR=0.74; 95%CI=0.59-0.92, p=0.01), dominant (OR=0.72; 95%CI=0.53-0.98, p=0.05), homozygous (OR=0.42; 95%CI=0.24-0.74, p=0.01) and recessive (OR=0.42; 95%CI=0.24-0.74, p=0.0004) models. However, in asymptomatic group it was associated with the increased chance of HBV infection. Haplotypes, ATT (OR=0.47; 95%CI=0.33-0.68, p=0.001), GTC (OR=0.68; 95%CI=0.51-0.92, p=0.01) protect while GTT (OR=2.01; 95%CI=(1.55-2.60), p<0.0001) predisposes the individuals to HBV infection. All of these p-values mentioned here were obtained after performing Bonferroni correction.

CONCLUSION

In conclusion, our findings revealed that mutant allele A of rs4958842, mutant allele C of rs4958843 and rs4958846 were associated with hepatitis B virus infection in the North Indian population.

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.

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.

Integrative analysis identifies genetic variant modulating MICA expression and altering susceptibility to persistent HBV infection

BACKGROUND & AIMS

Genome-wide association studies have identified multiple genetic signals associated with the risk of persistent hepatitis B virus (HBV) infection and HBV-related hepatocellular carcinoma. However, the majority of the associated variants may only be markers of functional variants and the underlying biological mechanisms remain elusive. We hypothesized that the functional variants with modulating transcription factor (TF) binding affinity in genome-wide association studies-identified loci may influence the risk of persistent HBV infection in Chinese people.

METHODS

A systematic bioinformatics approach was implemented to prioritize potential functional variants that may influence TF binding. A two-stage case-control study, including 1595 HBV-persistent carriers and 1590 subjects with HBV natural clearance, was conducted to examine the associations between candidate variants and susceptibility to persistent HBV infection. Biological assays were carried out to elucidate the underlying mechanism of the associated genetic variants.

RESULTS

Twelve candidate variants were identified, and rs2523454 G > A increased the risk of persistent HBV infection (dominant model: OR_combined  = 1.37, 95% CI = 1.19-1.58, P = 1.610 × 10^-5 ). Functional assays indicated that the rs2523454 A allele significantly decreased transcriptional activity compared to the G allele by influencing TF-binding affinity. In addition, expression quantitative trait loci analyses revealed that the A allele was associated with the reduced expression of MICA (P < 0.01).

CONCLUSIONS

Our findings suggest that the germline G > A variation at rs2523454 may influence TF-DNA interaction, downregulate the expression of MICA and play an important role in the development of persistent HBV infection in the Chinese population.

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.

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.

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.

Association of TERT polymorphisms with chronic hepatitis B in a Chinese Han population

In this study, we investigated the association between the polymorphisms of telomerase reverse transcriptase (TERT) gene and the risk of chronic hepatitis B (CHB) in a Chinese Han population. Four single nucleotide polymorphisms (SNPs) in TERT (rs10069690, rs2242652, rs2853677 and rs2853676) were genotyped from 224 CHB patients and 300 healthy controls using the Sequenom Mass-ARRAY platform. We used genetic model, haplotype analyses, chi-square test, logistic regression analysis to evaluate the association between SNPs and CHB risk. The relative risk was estimated by odd ratios (ORs) and 95% confidence intervals (CIs). We found that rs10069690 was significantly associated with an increased CHB risk in the dominant model (adjusted OR = 1.70, 95% CI: 1.06–2.71, P = 0.031) and additive model (adjusted OR = 1.62, 95% CI: 1.09–2.41, P = 0.018). The haplotype “TA” (rs10069690 and rs2242652) was found to be associated with an increased risk of CHB (adjusted OR = 1.58, 95% CI: 1.05–2.38, P = 0.027). Our results suggested potential genetic contributes for TERT in CHB development in a Chinese Han population. Future functional and association studies with larger sample sizes are required to confirm these findings.

Host genetic factors in predicting response status in chronic hepatitis B patients discontinuing nucleos(t)ide analogs

BACKGROUND/AIMS

The optimal duration of nucleos(t)ide analogs (NAs) therapy in chronic hepatitis B (CHB) patients remains unsatisfactory. Previous studies have confirmed the important role of host genetic factors in determining the outcome of HBV infection. This study tries to determine the role of host genetic factors in predicting response status in CHB patients discontinuing NAs according to stringent cessation criteria.

PATIENTS AND METHODS

Participating patients came from a prospective NAs- discontinuation cohort since June 1999. Six single-nucleotide polymorphisms (SNPs) were selected according to previous report. SNaPshot assay was used for DNA SNPs analyses.

RESULTS

Seventy-six CHB patients were enrolled in our study, of which 61 patients were HBeAg-positive and 15 patients were HBeAg-negative. rs1883832 in the Kozak sequence of CD40 displayed an AUROC of 0.778 in predicting response status in CHB patients with HBeAg seroconversion and a genotype of CT was associated with sustained response in this subpopulation. The diagnostic performance of combinative index (rs1883832, age, and HBsAg at discontinuation) seemed to be better than that of rs1883832, but no statistical difference was observed. rs1883832 was also evaluated as an independent factor for response status by multivariate logistic regression. For HBeAg-negative CHB patients, rs9277535 at HLA-DP presents a Spearman correlation coefficient of 0.582 (P = 0.023) with virological relapse after discontinuation of NAs.

CONCLUSIONS

rs1883832 serves as a valuable predictive factor for CHB patients with HBeAg seroconversion. rs9277535 at HLA-DP might also be a valuable predictive factor for CHB patients with HBeAg-negative, however, further verifications are recommended due to study limitations.

Cytochrome P450 Genes (CYP2E1 and CYP1A1) Variants and Susceptibility to Chronic Hepatitis B Virus Infection

Hepatitis B virus (HBV) infection is a worldwide health concern which is associated with significant morbidity and mortality. Both viral and host factors have a significant effect on infection, replication and pathogenesis of HBV. The aim of this study was to investigate the effect of CYP2E1 and CYP1A1 genetic variants on susceptibility to HBV. 143 individuals including 54 chronic HBV patients and 89 healthy controls were enrolled in the genotyping procedure. rs2031920 and rs3813867 at CYP2E1 as well as rs4646421 and rs2198843 at CYP1A1 loci were studied in all subjects using PCR-RFLP (restriction fragment length polymorphism) analysis. Both variants at CYP2E1 locus were monomorphic in all studied subjects. Genotype frequency of rs4646421 was significantly different between chronic HBV patients and healthy blood donors (P = 0.04, OR 4.31; 95% CI 1.04-17.7). Furthermore, individuals carrying at least one C allele (CC or CT genotypes) for rs4646421 seemed to have a decrease risk of hepatitis in comparison with TT genotype (P = 0.039). Our results showed a relationship between rs4646421 TT genotype (rare genotype) and the risk for developing chronic HBV infection (four times higher). Further studies are needed to examine the role of CYP1A1 polymorphism in susceptibility to chronic HBV infection.

Clinical features of treatment-naive patients with hepatitis B virus infection: A community-based survey from high- and intermediate-hepatitis B endemicity regions in Southeast China

The aim of study was to investigate the clinical features of treatment-naive patients in 2 regions with high- and intermediate-hepatitis B endemicity level in Southeast China and provide the baseline data for monitoring health or planning therapy.This study included 8207 cases of treatment-naive patients with hepatitis B virus (HBV) infection from Yuhuan (YH, high-hepatitis B endemicity region) and Shaoxing (SX, intermediate-hepatitis B endemicity region) during 2014-2015. Clinical data were collected from the patients. Blood samples were kept for detecting hepatitis B surface antigen, hepatitis B envelope antigen (HBeAg), hepatitis B envelope antibody, hepatitis B surface antibody, hepatitis B core antibody, liver function, HBV deoxyribonucleic acid, and alpha-fetoprotein. All persons underwent B ultrasound to exclude liver cirrhosis or cancer.Of all 8207 HBsAg-positive patients, 52.9% patients were in the low-replication (LR) stage and 30.3% in the HBeAg-negative chronic hepatitis B (ENH) stage; 8.8% cases were in the ENH stage with elevated alanine aminotransferase (ALT). More male than female patients were in immune clearance (IC) or ENH stages with elevated ALT (10.4% vs 4.8%, 12.1% vs 5.3%, respectively, P < .05). The percentage of patients in IC and immune tolerant (IT) stages declined with increasing age, whereas the percentages of ENH with elevated ALT stage were highest in 40 to 60 years.The percentage of patients in IT and IC stages was higher in YH than in SX (9.4% vs 3.8%, 9.9% vs 4.2%, respectively, P < .05). More patients had HBVDNA≥10 IU/mL in YH than in SX (24.6% vs 16.0%, P < .05), and more male than female patients had HBVDNA≥10 IU/mL(24.5% vs 17.9%, P < .05).Clinical features varied in treatment-naive patients with HBV infection between different genders and regions. More attention should be paid to the surveillance and therapy of patients in YH especially male patients for the prevention and prognosis of hepatitis B.

Cytokine-Mediated Immunopathogenesis of Hepatitis B Virus Infections

Hepatitis B virus (HBV) infection is a worldwide health problem, with approximately one third of populations have been infected, among which 3-5% of adults and more than 90% of children developed to chronic HBV infection. Host immune factors play essential roles in the outcome of HBV infection. Thus, ineffective immune response against HBV may result in persistent virus replications and liver necroinflammations, then lead to chronic HBV infection, liver cirrhosis, and even hepatocellular carcinoma. Cytokine balance was shown to be an important immune characteristic in the development and progression of hepatitis B, as well as in an effective antiviral immunity. Large numbers of cytokines are not only involved in the initiation and regulation of immune responses but also contributing directly or indirectly to the inhibition of virus replication. Besides, cytokines initiate downstream signaling pathway activities by binding to specific receptors expressed on the target cells and play important roles in the responses against viral infections and, therefore, might affect susceptibility to HBV and/or the natural course of the infection. Since cytokines are the primary causes of inflammation and mediates liver injury after HBV infection, we have discussed recent advances on the roles of various cytokines [including T helper type 1 cells (Th1), Th2, Th17, regulatory T cells (Treg)-related cytokines] in different phases of HBV infection and cytokine-related mechanisms for impaired viral control and liver damage during HBV infection. We then focus on experimental therapeutic applications of cytokines to gain a better understanding of this newly emerging aspect of disease pathogenesis.

Correlations between ASCC3 Gene Polymorphisms and Chronic Hepatitis B in a Chinese Han Population

We have previously identified 8 SNPs in Han Chinese HBV carriers that are associated with disease progression. Although not well studied, genetic factors may also play a significant role in developing chronic HBV disease after exposure. We extend the effect of these eight SNPs on persistent HBV infection in this study. A total of 875 unrelated Han Chinese, 493 chronic hepatitis B subjects (CHB) and 382 HBV clearance individuals (Clear), were recruited from Hubei Province from September 2007 to March 2010. SNPs were verified by using TaqMan 7900HT Sequence Detection System. By using multiple logistic regression analysis, each of the 8 SNP associations was tested using 3 different genetic models (Dominant, Recessive and Additive model), in 4 types of analyses (full sample, men, women, age stratified). A Bonferroni correction was used to account for multiple statistical tests for each SNP association (P<0.05/8 = 0.0063). A significant correlation was observed at SNP rs10485138 located in ASCC3 gene in female patients (OR, 0.445; 95% CI, 0.253–0.784; P = 0.005). Females bearing C allele infected by HBV had an increased susceptibility to CHB compared with those T allele carriers. Our results indicated that SNP rs10485138 located in ASCC3 gene was associated with persistent HBV infection in Han Chinese.

Genetic variants in five novel loci including CFB and CD40 predispose to chronic hepatitis B

Hepatitis B virus affects more than 2 billion people worldwide, 350 million of which have developed chronic hepatitis B (CHB). The genetic factors that confer CHB risk are still largely unknown. We sought to identify genetic variants for CHB susceptibility in the Chinese population. We undertook a genome-wide association study (GWAS) in 2,514 CHB cases and 1,130 normal controls from eastern China. We replicated 33 of the most promising signals and eight previously reported CHB risk loci through a two-stage validation totaling 6,600 CHB cases and 8,127 controls in four independent populations, of which two populations were recruited from eastern China, one from northern China and one from southern China. The joint analyses of 9,114 CHB cases and 9,257 controls revealed significant association of CHB risk with five novel loci. Four loci are located in the human leukocyte antigen (HLA) region at 6p21.3, including two nonsynonymous variants (rs12614 [R32W] in complement factor B [CFB], Pmeta =1.28 × 10(-34) ; and rs422951 [T320A] in NOTCH4, Pmeta  = 5.33 × 10(-16) ); one synonymous variant (rs378352 in HLA-DOA corresponding to HLA-DOA*010101, Pmeta  = 1.04 × 10(-23) ); and one noncoding variant (rs2853953 near HLA-C, Pmeta  = 5.06 × 10(-20) ). Another locus is located at 20q13.1 (rs1883832 in the Kozak sequence of CD40, Pmeta  = 2.95 × 10(-15) ). Additionally, we validated seven of eight previously reported CHB susceptibility loci (rs3130542 at HLA-C, rs1419881 at TCF19, rs652888 at EHMT2, rs2856718 at HLA-DQB1, rs7453920 at HLA-DQB2, rs3077 at HLA-DPA1, and rs9277535 at HLA-DPA2, which are all located in the HLA region, 9.84 × 10(-71)  ≤ Pmeta  ≤ 9.92 × 10(-7) ).

CONCLUSION

Our GWAS identified five novel susceptibility loci for CHB. These findings improve the understanding of CHB etiology and may provide new targets for prevention and treatment of this disease.

IL-18, TNF, and IFN-γ alleles and genotypes are associated with susceptibility to chronic hepatitis B infection and severity of liver injury

This study evaluated the association of polymorphisms in the IL-18 (-607C/A and -137C/G), IFNγ (+874 A/T), and TNF (-238 A/G and -308 A/G) genes with susceptibility to HBV infection and severity of liver injury. A total of 259 chronic HBV-infected patients followed at the University Hospital, Faculty of Medicine of Ribeirão Preto, São Paulo, Brazil, and 202 healthy individuals were studied. Four Single Nucleotide Polymorphisms (SNPs) were amplified by Polymerase Chain Reaction (PCR). Liver biopsy was performed in 212 HBV-infected patients and classified according to severity of liver fibrosis (scores 0-4) and necroinflammatory activity (HAI scores 0-18). TNF-308*A allele (P < 0.001; OR = 2.16) and TNF -308 AA genotype (P = 0.026; OR = 5.43) were associated with susceptibility to HBV infection. An association was found between severe liver fibrosis when compared to mild fibrosis and the following polymorphisms: Alleles IL-18 -137*G (P = 0.004; OR = 3.45), TNF -308*A (P < 0.001; OR = 3.39), and IFNγ +874*T (P = 0.029; OR = 1.85) and IL-18 -137 GG genotype (P = 0.009; OR = 3.70). No significant association was found between IL-18 (-607 A/C) polymorphism and severity of liver fibrosis. Alleles IL-18 -137*G (P = 0.028; OR = 2.64) and TNF-308*A (P = 0.002; OR = 3.06) and IL-18 -137 GG genotype (P = 0.011; OR = 4.20) were associated with severe necroinflammatory activity (HAI>12) when compared to mild necroinflammatory activity (HAI 1-8). The results suggest that IL-18 -137C/G, TNF-308 G/A and IFNγ +874 A/T SNPs were associated to more severe liver injury in chronic HBV infection. TNF -308*A allele and TNF -308 AA genotype could play a role in the susceptibility to HBV infection.

Interleukin 18 gene promoter polymorphisms and susceptibility to chronic hepatitis B infection: a review study

CONTEXT

The variation in clinical outcome of hepatitis B virus (HBV) infection is determined by virological, immunological and host genetic factors. Genes encoding cytokines are one of the candidates among host genetic factors. Polymorphisms in gene promoter can lead to different levels of cytokine expression and unique immune response. Being involved in the inflammatory cytokine network, interleukin-18 (IL-18) plays an important role in pathogenesis of HBV infection. The aim of this review is considering available literature on the association between IL-18 gene promoter single nucleotide polymorphisms (-137 C/G and -607 A/C) and susceptibility to chronic HBV infection.

EVIDENCE ACQUISITION

Published literature from PubMed, EMBASE, and other databases were retrieved. All studies investigating the association of IL-18 gene promoter SNPs, -137 C/G and -607 A/C, with susceptibility to chronic HBV infection were included.

RESULTS

Findings showed that the genotype -607A/A is associated with the susceptibility to chronic hepatitis B. Furthermore, allele C at position -137 is suggested to play a protective role against development of chronic HBV infection.

CONCLUSIONS

Host genetic factors play an important role in determining the outcome of HBV infection. It is suggested that IL-18 genotype -607 A/A is associated with susceptibility to chronic hepatitis B. Furthermore, the carriage of allele C at position -137 may play a protective role in the development of chronic HBV infection.

Tumour necrosis factor-alpha, interleukin-10, interferon-gamma and vitamin D receptor gene polymorphisms in patients with chronic hepatitis delta

No data exist to assess certain polymorphisms that have a potential effect on the immune response in patients with chronic hepatitis delta (CHD). The aim of this study was to investigate polymorphisms in 6 polymorphic sites: IL-10 -1082 (rs1800896), IL-10 -627 (rs1800872), IFN-γ +874 (rs62559044), TNF-α -308 (rs1800629), vitamin D receptor (VDR) FokI (rs2228570) and VDR TaqI (rs731236). The genotypes of 67 patients with CHD and 119 patients with chronic hepatitis B (CHB) were compared. In addition, 56 individuals with resolved hepatitis B virus (HBV) infection were used as a control group for patients with CHB. Polymorphisms in TNF-α, IL-10, and VDR genes were analysed using polymerase chain reaction/restriction fragment length polymorphism methods. The IFN-γ gene polymorphism was detected by allele-specific polymerase chain reaction (PCR). Patients with CDH were more likely to have advanced liver disease compared with patients with CHB (P < 0.0001). IL-10 -1082 and VDR TaqI polymorphisms showed significant differences between patients with CHD and CHB. The high secretory IL-10 -1082 genotype GG was less frequent in CHD compared with patients with CHB and resolved HBV (17.7%, 37.4% and 47.1%, respectively (P < 0.05 for CHD vs CHB and resolved HBV). The frequency of the high secretory VDR TaqI TT genotype was 86.6% in patients with CHD, 62.7% in patients with CHB and 62.5% in resolved HBV individuals (CHD vs CHB: P < 0.05). None of the polymorphisms analysed had an effect on HBV persistence. IL-10 -1082 and VDR TaqI polymorphisms may contribute to the more severe liver disease associated with CHD compared with CHB.

New loci associated with chronic hepatitis B virus infection in Han Chinese

Chronic hepatitis B virus (HBV) infection is a challenging global health problem. To identify genetic loci involved in chronic HBV infection, we designed a three-phase genome-wide association study in Han Chinese populations. The discovery phase included 951 HBV carriers (cases) and 937 individuals who had naturally cleared HBV infection (controls) and was followed by independent replications with a total of 2,248 cases and 3,051 controls and additional replications with 1,982 HBV carriers and 2,622 controls from the general population. We identified two new loci associated with chronic HBV infection: rs3130542 at 6p21.33 (near HLA-C, odds ratio (OR) = 1.33, P = 9.49 × 10(-14)) and rs4821116 at 22q11.21 (in UBE2L3, OR = 0.82, P = 1.71 × 10(-12)). Additionally, we replicated the previously identified associations of HLA-DP and HLA-DQ variants at 6p21.32 with chronic HBV infection. These findings highlight the importance of HLA-C and UBE2L3 in the clearance of HBV infection in addition to HLA-DP and HLA-DQ.

Genome-wide association study of chronic hepatitis B virus infection reveals a novel candidate risk allele on 11q22.3

BACKGROUND

Hepatitis B virus (HBV) affects millions of people worldwide. While some people are able to clear the virus following the first encounter, those who develop chronic infection manifest remarkable clinical heterogeneity that ranges from asymptomatic carrier state to cirrhosis and hepatocellular carcinoma. Despite extensive studies, little is known about genetic host factors that influence the outcome of chronic HBV infection. Thus, we conducted this study to investigate the genetic risk of developing active liver disease among chronic carriers of HBV.

METHODS

In this study, we conducted a genome-wide association study (GWAS) on a cohort of patients with chronic HBV infection.

RESULTS

One particular SNP that is 16 kb upstream of Ferredoxin 1 was found to have an association with complicated chronic HBV infection (cirrhosis and hepatocellular carcinoma) that reached GWAS significance, and was successfully validated on an independent set of samples.

CONCLUSIONS

This first GWAS in an Arab population further demonstrates the utility of this approach in elucidating the genetic risk of HBV infection-related complications and highlights the advantage of conducting GWAS in different ethnicities to achieve that goal.

Host genetic factors in hepatitis B infection, liver cancer and vaccination response: a review with a focus on Africa

The disease burden due to hepatitis B virus (HBV) infection remains significant; 350 million people are infected world-wide, and around half a million deaths each year are due to HBV-related liver disease and hepatocellular carcinoma (HCC). Infant immunisation against infection was introduced in the early 1980s, the vaccine is routinely administered across regions where the disease is endemic and has been shown to be safe and effective. However, the large number of older individuals with persistent infection means that disease will not be reduced significantly for several decades. Furthermore, failure to respond to the vaccination has been observed in about 5% of vaccinees and to date we have limited information on the durability of vaccine protection against infection. Hepatitis B infection and disease pathogenesis are known to be influenced by a number of factors including host genetics factors. This review aims to give an overview of the role of genetic variation in persistent HBV infection and the development of liver disease including HCC. Vaccine-induced immunity is, at least in part, heritable and we also discuss findings on the genetic control of responses to HBV vaccination. The epidemiology of HBV infection differs by world region, as does the genetic makeup of individuals originating from different regions. This review focuses on the situation in Africa, where hepatitis B is highly endemic.

A genome-wide association study with DNA pooling identifies the variant rs11866328 in the GRIN2A gene that affects disease progression of chronic HBV infection

Host genetics play a vital role in determining clinical outcomes of hepatitis B virus (HBV) infection. To identify novel susceptibility loci to HBV progression, we carried out a genome-wide association study with DNA pooling. This study assessed the relationship between 8 highly-ranked SNPs selected from our DNA pool and disease progression of HBV infection in two independent case-control studies. The first population included 628 asymptomatic HBV carriers (AsC) and 1729 progressed HBV carriers recruited from Hubei Province in south China. The second population was composed of 226 AsC and 215 progressed HBV carriers recruited from Shandong Province in north China. Of the 8 SNPs, variant rs11866328 (G/T), located in the glutamate receptor ionotropic N-methyl D-aspartate 2A (GRIN2A) gene, was replicated and had significant associations with disease progression of HBV infection in the DNA pooling stage both in the Hubei (OR 1.65; 95% CI 1.34,2.02; p=1.96 × 10(-6); additive model), and in the Shandong (OR 1.73; 95% CI 1.14,2.65; p=1.00×10(-2); additive model) population. Polymorphism rs11866328 in the GRIN2A gene might be a genetic variant underlying the susceptibility of HBV carriers to disease progression.

Ficolin-2 levels and FCN2 haplotypes influence hepatitis B infection outcome in Vietnamese patients

Human Ficolin-2 (L-ficolins) encoded by FCN2 gene is a soluble serum protein that plays an important role in innate immunity and is mainly expressed in the liver. Ficolin-2 serum levels and FCN2 single nucleotide polymorphisms were associated to several infectious diseases. We initially screened the complete FCN2 gene in 48 healthy individuals of Vietnamese ethnicity. We genotyped a Vietnamese cohort comprising of 423 clinically classified hepatitis B virus patients and 303 controls for functional single nucleotide polymorphisms in the promoter region (-986G>A, -602G>A, -4A>G) and in exon 8 (+6424G>T) by real-time PCR and investigated the contribution of FCN2 genotypes and haplotypes to serum Ficolin-2 levels, viral load and liver enzyme levels. Haplotypes differed significantly between patients and controls (P = 0.002) and the haplotype AGGG was found frequently in controls in comparison to patients with hepatitis B virus and hepatocellular carcinoma (P = 0.0002 and P<0.0001) conferring a protective effect. Ficolin-2 levels differed significantly between patients and controls (p<0.0001). Patients with acute hepatitis B had higher serum Ficolin-2 levels compared to other patient groups and controls.The viral load was observed to be significantly distributed among the haplotypes (P = 0.04) and the AAAG haplotype contributed to higher Ficolin-2 levels and to viral load. Four novel single nucleotide polymorphisms in introns (-941G>T, -310G>A, +2363G>A, +4882G>A) and one synonymous mutation in exon 8 (+6485G>T) was observed. Strong linkage was found between the variant -986G>A and -4A>G. The very first study on Vietnamese cohort associates both Ficolin-2 serum levels and FCN2 haplotypes to hepatitis B virus infection and subsequent disease progression.

Association of CISH -292A/T genetic variant with hepatitis B virus infection

Cytokine-inducible SRC homology 2 domain protein (CISH) is a suppressor of cytokine signaling that controls interleukin-2 signaling pathway. We investigated the single nucleotide polymorphism (SNP) -292A>T in 473 Vietnamese hepatitis B virus (HBV) carriers and 416 healthy controls. CISH variants at -292A>T were associated to HBV infection (Allelic: OR, 1.22 95% CI, 1-1.49; P = 0.04; Recessive: OR, 1.69 95% CI 1.23-2.54; P = 0.007). A gene dose effect for the risk allele -292T was observed (P = 0.04). The level of interleukin 2 and liver enzymes such as alanine transaminase, aspartate transaminase, total bilirubin, and direct bilirubin were not associated to CISH polymorphism at position -292A>T This study associated the vital role of CISH SNP -292A>T variant to hepatitis B virus infection in a Vietnamese population.

Hepatocellular carcinoma and other liver disease among Greenlanders chronically infected with hepatitis B virus: a population-based study

BACKGROUND

In Greenland, the prevalence of hepatitis B surface antigen carriers, reflecting chronic hepatitis B virus (HBV) infection, is 5%-10%. However, the incidence of cirrhosis and hepatocellular carcinoma in this population has been reported to be low. We investigated this discrepancy in a large population-based cohort study.

METHODS

In total, 8879 Greenlanders (16% of the population) were recruited for population-based surveys performed from May 5 to July 7, 1987, and from November 1 to November 21, 1998, with follow-up until March 31, 2010. HBV status was based on serological testing, supplemented by data from all available HBV registries in Greenland to determine changes in HBV status over time. Information on morbidity and mortality was obtained from the Patient Discharge Registry, the Cancer Registry, and the Central Registration System. Sex, age, ethnicity, and period-adjusted incidence rate ratios (IRRs) were estimated using Poisson regression. World standardized rates were derived from these and World Health Organization data.

RESULTS

The 650 chronically HBV-infected persons had higher rates of hepatocellular carcinoma (adjusted IRR = 8.70; 95% CI = 2.06 to 36.7), liver disease (adjusted IRR = 5.73, 95% CI = 3.52 to 9.34), and all-cause mortality (adjusted IRR = 1.47; 95% CI = 1.21 to 1.79) than the 5160 HBV-negative persons. However, the world standardized incidence rates of hepatocellular carcinoma (38.5 cancers per 100 000 person-years) and cirrhosis (24 cases per 100 000 person-years) among chronically HBV-infected persons were low compared with results from population-based studies from countries with low, intermediate, and high rates of endemic HBV infection.

CONCLUSION

The relatively low incidence of hepatocellular carcinoma and other HBV-related morbidity among chronic HBV-infected persons in Greenland suggest a more benign course of HBV among the Greenlandic Inuit than in populations in other parts of the world.

TLR7 and TLR8 gene variations and susceptibility to hepatitis C virus infection

Toll-like receptors (TLRs) play pivotal roles in the innate immune system and control inflammatory responses and adaptive immunity. We previously evaluated associations between TLR7 and TLR8 gene SNPs and susceptibility to hepatitis C virus (HCV) infection. Our results suggested that TLR7IVS2-151G and TLR8-129G alleles were present at higher frequency in males of an HCV-infected group as compared to a control group (24.1% vs. 14.4%, p = 0.028; 17.6% vs. 6.8%, p = 0.004, respectively). Based upon their recognition of single stranded viral RNA, this suggested that TLR7 and TLR8 played a significant role in anti-HCV immune responses. Here, we studied the functional effects of these polymorphisms by analyzing the mRNA expressions of TLR7 and TLR8 and cytokine production induced ex vivo by TLR7- and TLR8-specific agonists using whole blood of subjects with different genotypes. The percentage of CD14+ cells from those with an AG haplotype that expressed TLR7 and TLR8 was significantly lower, but higher in intensity compared to cells from those with GG and AC haplotypes. Cells from those with an AG haplotype produced more IFN-α and less amounts of pro-inflammatory cytokines upon stimulation. This suggests that variations in TLR7 and TLR8 genes might impair immune responses during HCV infection.

Effects of variant rs346473 in ARHGAP24 gene on disease progression of HBV infection in Han Chinese population

Host genetic, environmental and viral factors are classified as three categories that determine clinical outcomes of hepatitis B virus (HBV) infection. The objective of this study was to detect the associations between polymorphisms rs346473 and rs346482 in Rho GTPase-activating protein 24 (ARHGAP24) gene and disease progression of HBV infection in Han Chinese population. These two SNPs were found by our DNA pooling using Affymetrix Genome-Wide Human Mapping SNP6.0 Array in HBV carriers, and verified by using TaqMan 7900HT Sequence Detection System with 758 progressed HBV carriers versus 300 asymptomatic HBV carriers (AsC) in a discovery phase and 971 progressed HBV carriers versus 328 AsC in a replication phase. Multivariable logistic regression revealed that individuals with genotype TT at variant rs346473 displayed remarkable correlations with disease progression of HBV infection both in the discovery phase (OR, 2.693; 95% CI, 1.928-3.760; P=6.2×10(-9); additive model) and the replication phase (OR, 1.490; 95% CI, 1.104-2.012; P=9.0×10(-3); additive model). These two SNPs were in strong linkage disequilibrium with D'=0.99 and r (2)=0.951, and haplotype TT disclosed an increased susceptibility to HBV progression (OR, 1.980; 95% CI, 1.538-2.545; P=8.1×10(-8)). These findings suggest that polymorphism rs346473 in the ARHGAP24 gene might be a part of the genetic variants underlying the susceptibility of HBV carriers to disease progression.

Hepatitis B virus acquisition and pathogenesis in childhood: host genetic determinants

The clinical course of hepatitis B virus (HBV) infection varies from spontaneous recovery to chronic persistent infection leading to severe liver injury. Mounting evidence has recently highlighted the influence of host genotype in the complex interplay between viral and host factors. Studies in adults have suggested the existence of a genetic predisposition to HBV infection secondary to certain defects in the host response. These defects include opsonic deficiency, compromised antigen processing and presentation by human leucocyte antigen variations, attenuated T- and B-cell response, impaired cytokine and chemokine release, and production of receptors for several pertinent factors such as vitamin D and estrogen. By contrast, little is known about the genetic factors involved in the susceptibility to HBV transmission in early childhood. Herein, we review the literature regarding the association between host genetics and susceptibility to primary HBV infection, and we discuss the prospects of investigation in this field. A better understanding of HBV infection immunopathogenesis in the critical period of infancy may allow the development of optimal and innovative prevention and treatment.

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

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

Association of mannose-binding lectin polymorphisms and HBV outcome in a South Indian population

Mannose binding lectin (MBL) is an important innate immune system pattern recognition molecule. The MBL gene polymorphisms are reported to play a crucial role in outcome of hepatitis B virus (HBV) infection. In this study, we ascertained the association of MBL genotypes with HBV outcome in a South Indian population. The MBL gene polymorphisms at codons 52, 54 and 57 of exon I, and promoter polymorphisms at -221 were typed by polymerase chain reaction-sequence specific primer in spontaneously recovered and in chronic HBV group. The allele frequency of codon 52 'C' was significantly higher in chronic HBV group than in the recovered group (98.5% vs. 93.6%; P = 0.003) and codon 52 'T' was significantly higher in recovered group than in the chronic group (6.4% vs. 1.5%; P = 0.003). In multivariate analysis, after adjusting for age, sex and state of origin, codon 52 'CC' and 'CT' genotypes were significantly associated with chronicity and recovery respectively [odds ratio (OR), 0.25; 95% confidence interval (CI), 0.08-0.80, P = 0.02] in co-dominant analyzing models. This was re-affirmed in analysis performed exclusively on Tamil Nadu subjects (OR, 0.23; 95% CI, 0.06-0.93, P = 0.039). The frequency of low/none haplotype (XY/O) was significantly higher in recovered group than in chronic group (15.6% vs 7.5%) and associated with spontaneous recovery (OR, 2.28; 95% CI, 1.04-4.99, P = 0.035). Our results provide preliminary evidence that inheritance of codon 52 genotypes and XY/O haplotype associated with low MBL level substantially determine the outcome of HBV infection in a sympatrically isolated South Indian population.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Molecular characteristics and stages of chronic hepatitis B virus infection

Hepatitis B virus (HBV) is a common viral pathogen that causes a substantial health burden worldwide. Remarkable progress has been made in our understanding of the natural stages of chronic HBV infection. A dynamic balance between viral replication and host immune response is pivotal to the pathogenesis of liver disease. Knowledge of the HBV genome organization and replication cycle can unravel HBV genotypes and molecular variants, which contribute to the heterogeneity in outcome of chronic HBV infection. Most HBV infections are spontaneously resolved in immunocompetent adults, whereas they become chronic in most neonates and infants at a great risk of developing complications such as cirrhosis and hepatocellular carcinoma (HCC). Those with chronic HBV infection may present in one of the four phases of infection: immune tolerance, immune clearance [hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB)], inactive carrier state, and reactivation (HBeAg-negative CHB). Understanding the dynamic nature of chronic HBV infection is crucial in the management of HBV carriers. Long-term monitoring and optimal timing of antiviral therapy for chronic HBV infection help to prevent progression of HBV-related liver disease to its later stage, particularly in patients with higher risk markers of HCC, such as serum DNA concentration, HBeAg status, serum aminotransferase, HBV genotypes, and pre-core or core mutants.

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

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

Clinical trial: effects of adefovir dipivoxil therapy in Asian and Caucasian patients with chronic hepatitis B

BACKGROUND

Two-thirds of the 350 million people infected with chronic hepatitis B virus live in the Asia-Pacific region. AIM To compare the effects of adefovir dipivoxil therapy between Asian and Caucasian patients with chronic hepatitis B.

METHODS

The safety and efficacy of 10 mg of adefovir dipivoxil was compared to placebo in 501 Asian (n = 259) or Caucasian (n = 242) HBeAg+ and HBeAg- chronic hepatitis B virus patients treated for 48 weeks in two randomized, double-blind, placebo-controlled studies.

RESULTS

At week 48, histological improvement was observed in 60% and 56% of Caucasian and Asian patients, respectively. Change in serum hepatitis B virus DNA from baseline to week 48 for the adefovir dipivoxil-treated patients was -3.89 and -3.70 log(10) copies/mL in Caucasian and Asian patients, respectively, while 34 per cent of Caucasian patients and 39 per cent of Asian patients had undetectable serum hepatitis B virus DNA (<400 copies/mL) at week 48. The percentage of patients achieving alanine aminotransferase (ALT) normalization at week 48 was similar in both groups (Caucasian 64 per cent, Asian 63 per cent). No patients developed resistance through week 48. No differences in adverse events or grade 3 or 4 laboratory abnormalities were observed between groups.

CONCLUSIONS

There were no significant differences in treatment response between Asians and Caucasians. Adefovir dipivoxil was well tolerated and no resistance developed up to week 48 in both racial groups.

Association of interleukin-18 gene polymorphism (-607A/A genotype) with susceptibility to chronic hepatitis B virus infection

Polymorphisms in the gene promoter can lead to different levels of cytokine expression and let some individuals have unique immune responses. Therefore, the association of single nucleotide polymorphism of interleukin (IL)-18 promoter region in chronic hepatitis B virus (HBV) infection was examined. The results demonstrated the significant involvement of genotype A/A at position -607 in patients (n = 140) when compared with healthy individuals (n = 140) [OR (95% CI) = 2.62 (1.36-5.09), P(c)= 0.009]. The frequencies of -607A/A, C/A, C/C genotypes were 27.86%, 48.57% and 23.57% in chronic HBV patients and 12.80%, 59.30% and 27.90% in healthy controls, respectively. No significant association at the position -137 was found between the two groups. The frequencies of -607A/-137G haplotype homozygosity were higher in the chronic HBV patients (17.14%) than in the controls (8.57%) [OR (95% CI) = 2.21 (1-4.93), P = 0.05], although this was not statistically significant when corrected for multiple comparison (P(c)= 0.40). In conclusion, this study proposes that A/A genotype at position -607 in IL-18 gene can be used as a new genetic maker in Thai population for predicting chronic hepatitis B development.