Genome-wide association of IL28B with response to pegylated interferon-alpha and ribavirin therapy for chronic hepatitis C

The recommended treatment for patients with chronic hepatitis C, pegylated interferon-alpha (PEG-IFN-alpha) plus ribavirin (RBV), does not provide sustained virologic response (SVR) in all patients. We report a genome-wide association study (GWAS) to null virological response (NVR) in the treatment of patients with hepatitis C virus (HCV) genotype 1 within a Japanese population. We found two SNPs near the gene IL28B on chromosome 19 to be strongly associated with NVR (rs12980275, P = 1.93 x 10(-13), and rs8099917, 3.11 x 10(-15)). We replicated these associations in an independent cohort (combined P values, 2.84 x 10(-27) (OR = 17.7; 95% CI = 10.0-31.3) and 2.68 x 10(-32) (OR = 27.1; 95% CI = 14.6-50.3), respectively). Compared to NVR, these SNPs were also associated with SVR (rs12980275, P = 3.99 x 10(-24), and rs8099917, P = 1.11 x 10(-27)). In further fine mapping of the region, seven SNPs (rs8105790, rs11881222, rs8103142, rs28416813, rs4803219, rs8099917 and rs7248668) located in the IL28B region showed the most significant associations (P = 5.52 x 10(-28)-2.68 x 10(-32); OR = 22.3-27.1). Real-time quantitative PCR assays in peripheral blood mononuclear cells showed lower IL28B expression levels in individuals carrying the minor alleles (P = 0.015).

Independent risk factors and predictive score for the development of hepatocellular carcinoma in chronic hepatitis B

BACKGROUND/AIMS

To determine whether gender, age, hepatitis B virus genotype, core promoter and precore mutations, HBeAg/ anti-HBe status, HBV DNA, ALT levels and cirrhosis on presentation were independent risk factors and derive a novel risk score for the development of HCC.

METHODS

CHB patients (820) were followed up (mean duration 76.8 months) for the occurrence of HCC.

RESULTS

The 5- and 10-year prevalence of HCC were 4.4% and 6.3%, respectively. Cox regression analysis showed that male gender (p = 0.025, RR 2.98), increasing age (p < 0.001, RR 1.07), higher HBV DNA levels (p = 0.02, RR 1.28), core promoter mutations (p = 0.007, RR 3.66), and presence of cirrhosis (p < 0.001, RR 7.31) were independent risks for the development of HCC. A risk score was derived and validated with sensitivity > 84% and specificity > 76% to predict the 5- and 10- year risks for the development of HCC. The AUC for the 5- and 10-year prediction were 0.88 and 0.89, respectively.

CONCLUSIONS

The risk score, based on age, gender, HBV DNA levels, core promoter mutations and cirrhosis, can estimate the chance of development of HCC in 5 and 10 years after presentation. It can be used to identify high-risk CHB patients for treatment and screening of HCC.

Hepatic ISG expression is associated with genetic variation in interleukin 28B and the outcome of IFN therapy for chronic hepatitis C

BACKGROUND & AIMS

Multiple viral and host factors are related to the treatment response to pegylated-interferon and ribavirin combination therapy; however, the clinical relevance and relationship of these factors have not yet been fully evaluated.

METHODS

We studied 168 patients with chronic hepatitis C who received pegylated-interferon and ribavirin combination therapy. Gene expression profiles in the livers of 91 patients were analyzed using an Affymetrix genechip (Affymetrix, Santa Clara, CA). The expression of interferon-stimulated genes (ISGs) was evaluated in all samples by real-time polymerase chain reaction. Genetic variation in interleukin 28B (IL28B; rs8099917) was determined in 91 patients.

RESULTS

Gene expression profiling of the liver differentiated patients into 2 groups: patients with up-regulated ISGs and patients with down-regulated ISGs. A high proportion of patients with no response to treatment was found in the up-regulated ISGs group (P=.002). Multivariate logistic regression analysis showed that ISGs (<3.5) (odds ratio [OR], 16.2; P<.001), fibrosis stage (F1-F2) (OR, 4.18; P=.003), and ISDR mutation (>or=2) (OR, 5.09; P=.003) were strongly associated with the viral response. The IL28B polymorphism of 91 patients showed that 66% were major homozygotes (TT), 30% were heterozygotes (TG), and 4% were minor homozygotes (GG). Interestingly, hepatic ISGs were associated with the IL28B polymorphism (OR, 18.1; P<.001), and its expression was significantly higher in patients with the minor genotype (TG or GG) than in those with the major genotype (TT).

CONCLUSIONS

The expression of hepatic ISGs is strongly associated with treatment response and genetic variation of IL28B. The differential role of host and viral factors as predicting factors may also be present.

The RNA sensor RIG-I dually functions as an innate sensor and direct antiviral factor for hepatitis B virus

Host innate recognition triggers key immune responses for viral elimination. The sensing mechanism of hepatitis B virus (HBV), a DNA virus, and the subsequent downstream signaling events remain to be fully clarified. Here we found that type III but not type I interferons are predominantly induced in human primary hepatocytes in response to HBV infection, through retinoic acid-inducible gene-I (RIG-I)-mediated sensing of the 5'-ε region of HBV pregenomic RNA. In addition, RIG-I could also counteract the interaction of HBV polymerase (P protein) with the 5'-ε region in an RNA-binding dependent manner, which consistently suppressed viral replication. Liposome-mediated delivery and vector-based expression of this ε region-derived RNA in liver abolished the HBV replication in human hepatocyte-chimeric mice. These findings identify an innate-recognition mechanism by which RIG-I dually functions as an HBV sensor activating innate signaling and to counteract viral polymerase in human hepatocytes.

A genetic variant of hepatitis B virus divergent from known human and ape genotypes isolated from a Japanese patient and provisionally assigned to new genotype J

Hepatitis B virus (HBV) of a novel genotype (J) was recovered from an 88-year-old Japanese patient with hepatocellular carcinoma who had a history of residing in Borneo during the World War II. It was divergent from eight human (A to H) and four ape (chimpanzee, gorilla, gibbon, and orangutan) HBV genotypes, as well as from a recently proposed ninth human genotype I, by 9.9 to 16.5% of the entire genomic sequence and did not have evidence of recombination with any of the nine human genotypes and four nonhuman genotypes. Based on a comparison of the entire nucleotide sequence against 1,440 HBV isolates reported, HBV/J was nearest to the gibbon and orangutan genotypes (mean divergences of 10.9 and 10.7%, respectively). Based on a comparison of four open reading frames, HBV/J was closer to gibbon/orangutan genotypes than to human genotypes in the P and large S genes and closest to Australian aboriginal strains (HBV/C4) and orangutan-derived strains in the S gene, whereas it was closer to human than ape genotypes in the C gene. HBV/J shared a deletion of 33 nucleotides at the start of preS1 region with C4 and gibbon genotypes, had an S-gene sequence similar to that of C4, and expressed the ayw subtype. Efficient infection, replication, and antigen expression by HBV/J were experimentally established in two chimeric mice with the liver repopulated for human hepatocytes. The HBV DNA sequence recovered from infected mice was identical to that in the inoculum. Since HBV/J is positioned phylogenetically in between human and ape genotypes, it may help to trace the origin of HBV and merits further epidemiological surveys.

A serum "sweet-doughnut" protein facilitates fibrosis evaluation and therapy assessment in patients with viral hepatitis

Although liver fibrosis reflects disease severity in chronic hepatitis patients, there has been no simple and accurate system to evaluate the therapeutic effect based on fibrosis. We developed a glycan-based immunoassay, FastLec-Hepa, to fill this unmet need. FastLec-Hepa automatically detects unique fibrosis-related glyco-alteration in serum hyperglycosylated Mac-2 binding protein within 20 min. The serum FastLec-Hepa counts increased with advancing fibrosis and illustrated significant differences in medians between all fibrosis stages. FastLec-Hepa is sufficiently sensitive and quantitative to evaluate the effects of PEG-interferon-α/ribavirin therapy in a short post-therapeutic interval. The obtained fibrosis progression is equivalent to -0.30 stages/year in patients with sustained virological response, and 0.01 stages/year in relapse/nonresponders. Furthermore, long-term follow-up of the severely affected patients found hepatocellular carcinoma developed in patients after therapy whose FastLec-Hepa counts remained above a designated cutoff value. FastLec-Hepa is the only assay currently available for clinically beneficial therapy evaluation through quantitation of disease severity.

A comparison of the molecular clock of hepatitis C virus in the United States and Japan predicts that hepatocellular carcinoma incidence in the United States will increase over the next two decades

The prevalence of hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) is considerably lower in the U.S. than in Japan. To elucidate this difference, we determined the time origin of the HCV epidemic in each country by using molecularly clocked long-term serial samples obtained from HCV carriers of genotypes 1a and 1b. The molecular clock estimated that HCV genotype 1 first appeared in Japan in around 1882, whereas emergence in the U.S. was delayed until around 1910. In addition, by statistical analysis using coalescent theory, the major spread time for HCV infection in Japan occurred in the 1930s, whereas widespread dissemination of HCV in the U.S. occurred in the 1960s. These estimates of viral spread time are consistent with epidemiologic observations and predict that the burden of HCC in the U.S. will increase in the next two to three decades, possibly to equal that currently experienced in Japan.

Influence of hepatitis B virus genotypes on the intra- and extracellular expression of viral DNA and antigens

Various genotypes of the hepatitis B virus (HBV) induce liver disease of distinct severity, but the underlying virological differences are not well defined. Huh7 cells were transfected with plasmids carrying 1.24-fold the HBV genome of different genotypes/subgenotypes (2 strains each for Aa/A1, Ae/A2, Ba/B2 and D; 3 each for Bj/B1 and C). HBV DNA levels in cell lysates, determined by Southern hybridization, were the highest for C followed by Bj/Ba and D/Ae (P < .01), and the lowest for Aa (P < .01), whereas in culture media, they were the highest for Bj, distantly followed by Ba/C/D and further by Ae/Aa (P < .01). The intracellular expression of core protein was more than 3-fold lower for Ae/Aa than the others. Hepatitis B e antigen (HBeAg) was excreted in a trend similar to that of HBV DNA with smaller differences. Secretion of hepatitis B surface antigen (HBsAg) was most abundant for Ae followed by Aa, Ba, Bj/C and remotely by D, which was consistent with mRNA levels. Cellular stress determined by the reporter assay for Grp78 promoter was higher for C and Ba than the other genotypes/subgenotypes (P < .01). Severe combined immunodeficiency mice transgenic for urokinase-type plasminogen activator (uPA/SCID), with the liver replaced for human hepatocytes, were inoculated with virions passed in mouse and recovered from culture supernatants. HBV DNA levels in their sera were higher for C than Ae by 2 logs during 4-7 weeks after inoculation. In conclusion, virological differences among HBV genotypes were demonstrated both in vitro and in vivo. These differences may influence HBV infections with distinct genotypes in clinical and epidemiological settings.

Influence of genotypes and precore mutations on fulminant or chronic outcome of acute hepatitis B virus infection

The outcome of acute hepatitis B virus (HBV) infection is variable, influenced by host and viral factors. From 1982 through 2004, 301 patients with acute HBV infection entered a multi-center cross-sectional study in Japan. Patients with fulminant hepatitis (n = 40) were older (44.7 +/- 16.3 vs. 36.0 +/- 14.3 years, P < .0017), less predominantly male (43% vs. 71%, P = .0005), less positive for hepatitis B e antigen (HBeAg) (23% vs. 60%, P < .0001), less infected with subgenotype Ae (0% vs. 13%, P < .05), and more frequently with Bj (30% vs. 4%, P < .0001) than those with acute self-limited hepatitis (n = 261). Precore (G1896A) and core-promoter (A1762T/G1764A) mutations were more frequent in patients with fulminant than acute self-limited hepatitis (53% vs. 9% and 50% vs. 17%, P < .0001 for both). HBV infection persisted in only three (1%) patients, and they represented 2 of the 23 infected with Ae and 1 of the 187 with the other subgenotypes (9% vs. 0.5%, P = .032); none of them received antiviral therapy. In multivariate analysis, age 34 years or older, Bj, HBeAg-negative, total bilirubin 10.0 mg/dL or greater, and G1896A mutation were independently associated with the fulminant outcome. In in vitro transfection experiments, the replication of Bj clone was markedly enhanced by introducing either G1896A or A1762T/G1764A mutation. In conclusion, persistence of HBV was rare (1%) and associated with Ae, whereas fulminant hepatitis was frequent (13%) and associated with Bj and lack of HBeAg as well as high replication due to precore mutation in patients with acute HBV infection.

Cyclosporin A and its analogs inhibit hepatitis B virus entry into cultured hepatocytes through targeting a membrane transporter, sodium taurocholate cotransporting polypeptide (NTCP)

Chronic hepatitis B virus (HBV) infection is a major public health problem worldwide. Although nucleos(t)ide analogs inhibiting viral reverse transcriptase are clinically available as anti-HBV agents, emergence of drug-resistant viruses highlights the need for new anti-HBV agents interfering with other targets. Here we report that cyclosporin A (CsA) can inhibit HBV entry into cultured hepatocytes. The anti-HBV effect of CsA was independent of binding to cyclophilin and calcineurin. Rather, blockade of HBV infection correlated with the ability to inhibit the transporter activity of sodium taurocholate cotransporting polypeptide (NTCP). We also found that HBV infection-susceptible cells, differentiated HepaRG cells and primary human hepatocytes expressed NTCP, while nonsusceptible cell lines did not. A series of compounds targeting NTCP could inhibit HBV infection. CsA inhibited the binding between NTCP and large envelope protein in vitro. Evaluation of CsA analogs identified a compound with higher anti-HBV potency, having a median inhibitory concentration <0.2 μM.

CONCLUSION

This study provides a proof of concept for the novel strategy to identify anti-HBV agents by targeting the candidate HBV receptor, NTCP, using CsA as a structural platform.

Hepatitis B virus genotype assignment using restriction fragment length polymorphism patterns

Hepatitis B virus (HBV) is classified into genotypes A-F, which is important for clinical and etiological investigations. To establish a simple genotyping method, 68 full-genomic sequences and 106 S gene sequences were analyzed by the molecular evolutionary method. HBV genotyping with the S gene sequence is consistent with genetic analysis using the full-genomic sequence. After alignment of the S sequences, genotype specific regions are identified and digested by the restriction enzymes, HphI, NciI, AlwI, EarI, and NlaIV. This HBV genotyping system using restriction fragment length polymorphism (RFLP) was confirmed to be correct when the PCR products of the S gene in 23 isolates collected from various countries were digested with this method. A restriction site for EarI in genotype B was absent in spite of its presence in all the other genotypes and genotype C has no restriction site for AlwI. Only genotype E is digested with NciI, while only genotype F has a restriction site for HphI. Genotype A can be distinguished by a single restriction enzyme site for NlaIV, while genotype D digestion with this enzyme results in two products that migrates at 265 and 186 bp. This simple and accurate HBV genotyping system using RFLP is considered to be useful for research on HBV.

Epidermal growth factor receptor is a host-entry cofactor triggering hepatitis B virus internalization

Sodium taurocholate cotransporting polypeptide (NTCP) is a host cell receptor required for hepatitis B virus (HBV) entry. However, the susceptibility of NTCP-expressing cells to HBV is diverse depending on the culture condition. Stimulation with epidermal growth factor (EGF) was found to potentiate cell susceptibility to HBV infection. Here, we show that EGF receptor (EGFR) plays a critical role in HBV virion internalization. In EGFR-knockdown cells, HBV or its preS1-specific fluorescence peptide attached to the cell surface, but its internalization was attenuated. PreS1 internalization and HBV infection could be rescued by complementation with functional EGFR. Interestingly, the HBV/preS1-NTCP complex at the cell surface was internalized concomitant with the endocytotic relocalization of EGFR. Molecular interaction between NTCP and EGFR was documented by immunoprecipitation assay. Upon dissociation from functional EGFR, NTCP no longer functioned to support viral infection, as demonstrated by either (i) the introduction of NTCP point mutation that disrupted its interaction with EGFR, (ii) the detrimental effect of decoy peptide interrupting the NTCP-EGFR interaction, or (iii) the pharmacological inactivation of EGFR. Together, these data support the crucial role of EGFR in mediating HBV-NTCP internalization into susceptible cells. EGFR thus provides a yet unidentified missing link from the cell-surface HBV-NTCP attachment to the viral invasion beyond the host cell membrane.

Geographical and genetic diversity of the human hepatitis B virus

Hepatitis B virus (HBV) is one of the most widely distributed viruses that infect humankind. Distinct clinical and virological characteristics of the HBV-infection have been reported in different geographical parts of the world and are increasingly associated with genetic diversity of the infecting virus. HBV is classified into genotypes and subgenotypes that are associated with ethnicity and geography. The genetic diversity of HBV in its various aspects has been the subject of extensive investigations during the last few decades. Since molecular epidemiology research tools have become widely available, the number of new publications in this field has grown exponentially. This review summarises the recent publications on the geographical distribution of genetic variants of HBV, and proposes updated criteria for the identification of new genotypes and subgenotypes of the virus.

Alterations of DNA methylation and histone modifications contribute to gene silencing in hepatocellular carcinomas

AIM

The aim of the present study was to examine DNA methylation and histone modification changes in hepatocellular carcinomas (HCC).

METHODS

DNA methylation in the P16, RASSF1a, progesterone receptor (PGR) and estrogen receptor alpha (ERalpha) promoters was determined by quantitative bisulfite-pyrosequencing technique in HCC patients. Histone H3-lysine (K) 4, H3-K9 and H3-K27 modifications in all these four genes were examined by chromatin immunoprecipitation (ChIP) assay in HCC cell lines. Expression of two DNA methyltransferases (DNMT1 and DNMT3b) and three histone methyltransferases (SUV39H1, G9a and EZH2) in HCC patients was measured by real-time polymerase chain reaction.

RESULTS

Aberrant DNA methylation was detected in all the HCC. Patients with DNA methylation in the RASSF1a, PGR andERalpha promoters in cancers also had substantial DNA methylation in their non-cancerous liver tissues, whereas DNA methylation in the P16 promoter was cancer specific. Epigenetic states in HCC cell lines showed that silencing of P16 and RASSF1a depended on DNA methylation and histone H3-K9 methylation. However, silencing of the PGR and ERalpha genes was more closely related to H3-K27 methylation rather than DNA methylation. Consistent with the alteration of histone status, higher expression of G9a and EZH2 was found in HCC than in non-cancerous liver tissues (P < 0.01).

CONCLUSION

These data suggest that multiple epigenetic silencing mechanisms are inappropriately active in HCC cells.

Reactivation of hepatitis B virus following systemic chemotherapy for malignant lymphoma

Reactivation of hepatitis B virus (HBV) has been reported not only in HBsAg-positive patients undergoing systemic chemotherapy, but also in a proportion of HBsAg-negative patients with HBc antibody and/or HBs antibody. Recently, rituximab-plus-steroid combination chemotherapy (R-CHOP, etc.) has been identified as a risk factor for HBV reactivation in HBsAg-negative patients with malignant lymphoma. Prophylaxis with antiviral drugs is essential for preventing HBV reactivation in HBsAg-positive patients, but there is little evidence on which to base the choice of drug or appropriate duration of prophylaxis. There are also few clinical data on HBsAg-negative patients and no established standard of care for such patients with HBV reactivation. Based on the limited number of previous reports, preemptive therapy, guided by serial HBV-DNA monitoring, is a reasonable strategy to prevent HBV reactivation in HBsAg-negative patients. However, clinical evidence alone is insufficient for determining optimal frequency of HBV-DNA monitoring during and after chemotherapy, or for determining when to stop preemptive therapy for HBV reactivation. Thus, well-designed clinical trials should be carried out to investigate the efficacy and safety of such preemptive therapy. Additionally, assessment of viral factors such as HBV genotypes and gene mutations may assist in the development of strategies to prevent the occurrence of severe hepatitis. In this review, we summarize the characteristics of HBV reactivation after systemic chemotherapy including rituximab, and propose a management strategy for malignant lymphoma patients suffering from HBV reactivation.

A new subtype (subgenotype) Ac (A3) of hepatitis B virus and recombination between genotypes A and E in Cameroon

Blood samples (n=544) from two different populations (Pygmies and Bantus) in Cameroon, West Africa, were analysed. Serological tests indicated that the anti-hepatitis C virus (HCV) prevalence in Bantus (20.3 %) was higher than that in Pygmies (2.3 %, P<0.0001), whereas the distribution of hepatitis B virus (HBV) serological markers was equally high in both populations: in total, 9.4, 17.3 and 86.8 % for HBsAg, anti-HBs and anti-HBc, respectively. HBV genotype A (HBV/A) and HBV/E were predominant (43.5 % each) in both populations, and HBV/D was found in a minority (13 %). The preS/S region was sequenced in nine cases (five HBV/A and four HBV/E) and the complete genome in six cases (four HBV/A and two HBV/E). Subsequent phylogenetic analysis revealed that the HBV/A strains were distinct from the subtypes (subgenotypes) described previously, Ae (A2) and Aa (A1), and in the preS/S region they clustered with previously reported sequences from Cameroon. Based on the nucleotide difference from Aa (A1) and Ae (A2), more than 4 % in the complete genome, the Cameroonian strains were suggested to represent a new subtype (subgenotype), designated HBV/Ac (A3). A high (3.9 %) nucleotide divergence in HBV/Ac (A3) strains suggested that the subtype (subgenotype) has a long natural history in the population of Cameroon. One of the HBV/Ac (A3) strains was found to be a recombinant with an HBV/E-specific sequence in the polymerase reverse transcriptase domain. Further cohort studies will be required to assess detailed epidemiological, virological and clinical characteristics of HBV/Ac (A3), as well as its recombinant form.

Risk for hepatocellular carcinoma with respect to hepatitis B virus genotypes B/C, specific mutations of enhancer II/core promoter/precore regions and HBV DNA levels

BACKGROUND/AIM

To examine the risks for hepatocellular carcinoma (HCC) with respect to hepatitis B virus (HBV) genotypes, specific viral mutations (MT), serum HBV DNA levels, and cirrhosis.

METHODS

HBV genotypes, 1653/1753/core promoter (CP)/precore MT and HBV DNA levels were determined in 248 HBV patients with HCC and 248 HBV controls.

RESULTS

Genotype C, CP-MT, T1653, HBV DNA levels >or=4 log(10) copies/ml and cirrhosis had a higher risk for HCC compared to patients with genotype B (p = 0.001, OR 1.9), CP wild-type (WT) (p<0.001, OR 4.1), C1653 (p = 0.028, OR 2.4), HBV DNA <4 log(10) copies/ml (p = 0.003, OR 2.1) and without cirrhosis (p<0.001, OR 4.0) respectively. Multivariate analysis showed that CP-MT, T1653, HBV DNA >or=4 log(10) copies/ml and cirrhosis were independent factors for HCC (all p<0.05). A receiver operating characteristics curve showed no cut-off HBV DNA level associated with minimal chance of HCC. Patients with CP-MT and cirrhosis had a 22.2-fold increased risk of HCC compared to patients with CP-WT and without cirrhosis. Patients with CP-MT and HBV DNA levels >or=4 log(10) copies/ml had a 7.2-fold increased risk of HCC compared to patients with CP-WT and HBV DNA levels <4 log(10) copies/ml. Patients with CP-MT and T1653 had a 9.9-fold increased risk of HCC compared to patients with wild-type for both regions.

CONCLUSIONS

CP-MT, T1653, HBV DNA levels >or=4 log(10) copies/ml and cirrhosis are independent factors for development of HCC. The risks increased substantially in patients having these factors in combination.

A case-control study for differences among hepatitis B virus infections of genotypes A (subtypes Aa and Ae) and D

There are two subtypes of hepatitis B virus genotype A (HBV/A) and they are provisionally designated Aa ("a" standing for Africa/Asia) and Ae ("e" for Europe). In a case-control study, 78 HBV/Aa, 78HBV/Ae, and 78HBV/D carriers from several countries were compared. The prevalence of HBe antigen (HBeAg) in serum was significantly lower in carriers of HBV/Aa than in carriers of HBV/Ae (31% vs. 49%; P = .033), with a difference more obvious in the carriers aged 30 years or younger (34% vs. 67%; P = .029). HBV DNA levels in the carriers of HBV/Aa (median, 3.46 log copies/mL; 95% CI, 2.93-3.95) were significantly lower than those of carriers of HBV/Ae (6.09 log copies/mL; 95% CI, 4.24-7.64) or of carriers of HBV/D (5.48 log copies/mL; 95% CI, 4.06-7.02), regardless of the HBeAg status (P < .001). The most specific and frequent substitutions in 54 HBV/Aa isolates were double substitutions for T1809 (100%) and T1812 (96%) immediately upstream of the precore initiation codon, which would interfere with the translation of HBeAg in HBV/Aa infections. They were not detected in 57 HBV/Ae or 61 HBV/D isolates examined. The double mutation in the core promoter (T1762/A1764) was more frequent in both HBV/Aa (50%) and HBV/Ae (44%) than in HBV/D isolates (25%; P < .01), whereas the precore mutation (A1896) occurred in HBV/D isolates only (48%; P < .0001). In conclusion, the clearance of HBeAg from serum may occur by different mechanisms in HBV/Aa, HBV/Ae, and HBV/D infections, which may influence clinical manifestations in the Western countries where both genotypes A and D are prevalent.

Interleukin-1 and tumor necrosis factor-α trigger restriction of hepatitis B virus infection via a cytidine deaminase activation-induced cytidine deaminase (AID)

Virus infection is restricted by intracellular immune responses in host cells, and this is typically modulated by stimulation of cytokines. The cytokines and host factors that determine the host cell restriction against hepatitis B virus (HBV) infection are not well understood. We screened 36 cytokines and chemokines to determine which were able to reduce the susceptibility of HepaRG cells to HBV infection. Here, we found that pretreatment with IL-1β and TNFα remarkably reduced the host cell susceptibility to HBV infection. This effect was mediated by activation of the NF-κB signaling pathway. A cytidine deaminase, activation-induced cytidine deaminase (AID), was up-regulated by both IL-1β and TNFα in a variety of hepatocyte cell lines and primary human hepatocytes. Another deaminase APOBEC3G was not induced by these proinflammatory cytokines. Knockdown of AID expression impaired the anti-HBV effect of IL-1β, and overexpression of AID antagonized HBV infection, suggesting that AID was one of the responsible factors for the anti-HBV activity of IL-1/TNFα. Although AID induced hypermutation of HBV DNA, this activity was dispensable for the anti-HBV activity. The antiviral effect of IL-1/TNFα was also observed on different HBV genotypes but not on hepatitis C virus. These results demonstrate that proinflammatory cytokines IL-1/TNFα trigger a novel antiviral mechanism involving AID to regulate host cell permissiveness to HBV infection.

Consumption of n-3 fatty acids and fish reduces risk of hepatocellular carcinoma

BACKGROUND & AIMS

Fish is a rich source of n-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA). Although consumption of fish and n-3 PUFA has been reported to protect against the development of some types of cancer, little is known about its association with hepatocellular carcinoma (HCC).

METHODS

We investigated the association between fish and n-3 PUFA consumption and HCC incidence (n = 398) in a population-based prospective cohort study of 90,296 Japanese subjects (aged, 45-74 y). Hazard ratios and 95% confidence intervals (CIs) for the highest vs the lowest quintile were estimated from multivariable adjusted Cox proportional hazards regression models. We also conducted subanalyses of subjects with known hepatitis B virus (HBV) or hepatitis C virus (HCV) status, and of subjects who were anti-HCV and/or hepatitis B surface antigen positive. All tests of statistical significance were 2-sided.

RESULTS

Among all subjects, consumption of n-3 PUFA-rich fish and individual n-3 PUFAs was associated inversely with HCC, in a dose-dependent manner. Hazard ratios for the highest vs lowest quintiles were 0.64 (95% CI, 0.42-0.96) for n-3 PUFA-rich fish, 0.56 (95% CI, 0.36-0.85) for EPA, 0.64 (95% CI, 0.41-0.98) for DPA, and 0.56 (95% CI, 0.35-0.87) for DHA. These inverse associations were similar irrespective of HCV or HBV status.

CONCLUSIONS

Consumption of n-3 PUFA-rich fish or n-3 PUFAs, particularly EPA, DPA, and DHA, appears to protect against the development of HCC, even among subjects with HBV and/or HCV infection.

Hepatitis B virus core-related antigens as markers for monitoring chronic hepatitis B infection

A sensitive chemiluminescence enzyme immunoassay has been developed for hepatitis B virus (HBV) core-related antigen (HBcrAg) detection. We aimed to investigate the usefulness of HBcrAg measurement for monitoring chronic hepatitis B disease. HBcrAg levels were measured by a chemiluminescence enzyme immunoassay in 54 untreated patients and 39 patients treated with either entecavir or lamivudine. The HBcrAg concentration correlated positively with the levels of serum HBV DNA (r = 0.820), intrahepatic total HBV DNA (r = 0.700), and covalently closed circular DNA (cccDNA) (r = 0.664; for all, P values were <0.001). A higher HBcrAg concentration was associated with a greater proportion of hepatitis B core antigen immunostaining. Although the differences were not statistically significant, patients with higher Knodell necroinflammation and fibrosis scores tended to have higher serum HBcrAg concentration levels. In the treated patients, the logarithmic reduction in HBcrAg at week 48 correlated positively with the logarithmic reduction of serum HBV DNA, intrahepatic total HBV DNA, and cccDNA. Of the 31 patients with undetectable serum HBV DNA (<300 copies/ml) at the end of treatment, 20 (65%) still had detectable HBcrAg. A greater reduction in posttreatment HBcrAg concentration was associated with histological improvement and a decrease in hepatitis B core antigen immunostaining. HBcrAg concentrations of <40,000 kU/ml at baseline and <200 kU/ml at week 24 were associated with a higher chance of having undetectable HBV DNA at week 48. In conclusion, serum HBcrAg levels correlated with HBV virological markers and reflected the chronic hepatitis B disease activity in the liver.

Gut Dysbiosis Associated With Hepatitis C Virus Infection

BACKGROUND

Little is known about the effect of hepatitis C virus (HCV) infection on gut microbiota and the relationship between alteration of gut microbiota and chronic hepatitis C (CHC) progression. We performed a comparative study of gut microbiota composition between CHC patients and healthy individuals.

METHODS

Fecal samples from 166 CHC patients were compared with those from 23 healthy individuals; the gut microbiota community was analyzed using 16S ribosomal RNA gene sequencing. CHC patients were diagnosed with persistently normal serum alanine aminotransferase without evidence of liver cirrhosis (LC) (PNALT, n = 18), chronic hepatitis (CH, n = 84), LC (n = 40), and hepatocellular carcinoma in LC (n = 24).

RESULTS

Compared with healthy individuals, bacterial diversity was lower in persons with HCV infection, with a decrease in the order Clostridiales and an increase in Streptococcus and Lactobacillus. Microbiota dysbiosis already appeared in the PNALT stage with the transient increase in Bacteroides and Enterobacteriaceae. Predicted metagenomics of microbial communities showed an increase in the urease gene mainly encoded by viridans streptococci during CHC progression, consistent with a significantly higher fecal pH in CH and LC patients than in healthy individuals or those in the PNALT stage.

CONCLUSIONS

HCV infection is associated with gut dysbiosis, even in patients with mild liver disease. Additionally, overgrowth of viridans streptococci can account for hyperammonemia in CH and LC. Further studies would help to propose a novel treatment strategy because the gut microbiome can be therapeutically altered, potentially reducing the complications of chronic liver disease.

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

Hepatitis B virus (HBV) infection can lead to serious liver diseases, including liver cirrhosis (LC) and hepatocellular carcinoma (HCC); however, about 85-90% of infected individuals become inactive carriers with sustained biochemical remission and very low risk of LC or HCC. To identify host genetic factors contributing to HBV clearance, we conducted genome-wide association studies (GWAS) and replication analysis using samples from HBV carriers and spontaneously HBV-resolved Japanese and Korean individuals. Association analysis in the Japanese and Korean data identified the HLA-DPA1 and HLA-DPB1 genes with P(meta) = 1.89×10⁻¹² for rs3077 and P(meta) = 9.69×10⁻¹⁰ for rs9277542. We also found that the HLA-DPA1 and HLA-DPB1 genes were significantly associated with protective effects against chronic hepatitis B (CHB) in Japanese, Korean and other Asian populations, including Chinese and Thai individuals (P(meta) = 4.40×10⁻¹⁹ for rs3077 and P(meta) = 1.28×10⁻¹⁵ for rs9277542). These results suggest that the associations between the HLA-DP locus and the protective effects against persistent HBV infection and with clearance of HBV were replicated widely in East Asian populations; however, there are no reports of GWAS in Caucasian or African populations. Based on the GWAS in this study, there were no significant SNPs associated with HCC development. To clarify the pathogenesis of CHB and the mechanisms of HBV clearance, further studies are necessary, including functional analyses of the HLA-DP molecule.

Molecular evolution of hepatitis B virus over 25 years

Determining the longitudinal molecular evolution of hepatitis B virus (HBV) is difficult due to HBV's genomic complexity and the need to study paired samples collected over long periods of time. In this study, serial samples were collected from eight hepatitis B virus e antigen-negative asymptomatic carriers of HBV genotype B in 1979 and 2004, thus providing a 25-year period to document the long-term molecular evolution of HBV. The rate, nature, and distribution of mutations that emerged over 25 years were determined by phylogenetic and linear regression analysis of full-length HBV genome sequences. Nucleotide hypervariability was observed within the polymerase and pre-S/S overlap region and within the core gene. The calculated mean number of nucleotide substitutions/site/year (7.9 x 10(-5)) was slightly higher than published estimates (1.5 x 10(-5) to 5 x 10(-5)). Nucleotide changes in the quasispecies population did not significantly alter the molecular evolutionary rate, based on linear regression analysis of evolutionary distances among serial clone pre-S region sequences. Therefore, the directly amplified or dominant sequence was sufficient to estimate the putative molecular evolutionary rate for these long-term serial samples. On average, the ratio of synonymous (dS) to nonsynonymous (dN) substitutions was highest for the polymerase-coding region and lowest for the core-coding region. The low dS/dN ratios observed within the core suggest that selection occurs within this gene region, possibly as an immune evasion strategy. The results of this study suggest that HBV sequence divergence may occur more rapidly than previously estimated, in a host immune phase-dependent manner.