Masashi Mizokami

Aim:  Currently, approximately 44 000 hepatitis C virus (HCV), 11 000 hepatitis B virus (HBV), and 1600 hepatitis E virus (HEV) sequences are available at the International Nucleotide Sequence Database Collaboration (INSDC, previously known as DDBJ/EMBL/GenBank), and the number of these virus sequences is growing rapidly. However, since INDSC is not specialized to hepatitis viruses, it is difficult to retrieve information of virological or clinical interests from it. Thus, it is quite worthwhile to construct a specialized database for the hepatitis virus sequences and to make it accessible to researchers worldwide.Methods:  We developed a WWW‐based database hepatitis virus database (HVDB), which contains all the HCV, HBV, and HEV sequences available at INSDC. In the HVDB, all piece sequences obtained from INSDC are arranged to the genomesequence of each virus. Also given in the database are the phylogenetic relationships of each locus on the genome among variants for each virus.Results:  Users of the database can easily retrieve entries (sequences with annotations) of the specific genotype by referring to the phylogenetic relationships or those of specific loci by referring to the genome map information. HVDB provides users with a tool for phylogenetic analysis that can be used in combination with the data retrieval tools.Conclusion:  The latest release is publicly accessible at the HVDB website: http://s2as02.genes.nig.ac.jp.

Hepatitis B virus (HBV) genotype B (HBV B) and genotype C (HBV C) are prevalent in Asia. Recently HBV B has been classified into two subtypes, HBV Ba, which is ubiquitous in Asia, and HBV Bj specific to Japan. However, little is known about etiological, virological and clinical differences among patients who have various genotypes and who developed hepatocellular carcinoma (HCC). We investigated the relation of HBV subgenotype with etiological and clinical differences of HCC patients between Taiwan and Okinawa in Japan. HBV Bj may be associated with lower incidence of HCC and older development of HCC while HBV Ba or HBV C may be associated withhigher incidence of HCC and younger development of HCC. In addition, we demonstrated the relationship of the specific mutation of HBV, T1653 mutation in the core promoter region, with development of HCC in Japanese patients with HBV C. These data suggest that great differences exist among patients with HCC who are infected with different HBV genotypes or genotype‐specific mutations.

Hepatitis B virus (HBV)‐associated nephropathy is considered as an immune‐mediated disorder which is dependent on interactions between viral, host, and environmental factors. But there are few reports that investigated the relationship between the development of HBV‐associated nephropathy and HBV genotypes and the mutations. To clarify the relationship between nephropathy and HBV genotype in Japan, six male patients with HBV‐associated nephropathy were examined. The complete genome sequences of HBV were determined directly and the specific mutations associated with the development of HBV‐associated nephropathy were examined by comparison of the alignments along with consensus sequences [HBV/A1 (Aa), A2 (Ae), B1 (Bj), B2 (Ba), C1 (Cs) and C2 (Ce)] retrieved from international database. The mean age of the six patients was 33.5 years. HBeAg was found in all patients and serum HBV–DNA levels were relatively high. Histological findings of renal tissues indicated five cases of membranous nephropathy and one membranoproliferative glomerulonephritis. HBV genotypes from the six patients were two HBV/A1, two A2 and two C2, suggesting HBV/A was predominant. G1862T mutation was observed in the two HBV/A1 patients, resulting in the pre‐core amino acid substitution with a switch from valine (Val) to phenylalanine (Phe). Only one patient had core deletions. It is concluded that HBV/A may be associated with membranous nephropathy, but little relationship between HBV gene mutations and the development of HBV‐associated nephropathy was observed. J. Med. Virol. 79:1305–1311, 2007. © Wiley‐Liss, Inc.

Of the 8 genotypes of HBV (genotypes A‐H), genotype G is unique in that it has an insertion in the core gene and two stop codons in the precore region preventing the synthesis of hepatitis B e antigen. Most individuals with genotype G are coinfected with other genotypes, typically genotype A. Mice with severe combined immunodeficiency disease carrying human hepatocytes were infected with HBV particles propagated in Huh7 cells in culture. Mice monoinfected with genotype G did not raise detectable HBV DNA in serum, although products of the core gene emerged 4 to 8 weeks after inoculation. When they were superinfected with genotype A at week 10, however, HBV DNA of genotype A developed, which was replaced almost completely by that of genotype G within 10 weeks. Such a rapid takeover was also observed in mice initially infected with genotype A or C and superinfected with genotype G. Similar viral dynamics occurred in mice simultaneously coinfected with genotypes G and A. Takeover was markedly enhanced in mice inoculated with a serum passage containing genotype G with a trace of genotype A. Coinfection of mice with genotypes G and A induced abundant cellular steatosis along with increased fibrosis in the liver, which was not detected in mice monoinfected with genotype A or G. Conclusion: Genotype G can monoinfect chimeric mice at very low levels, and its replication increases maredly when coinfected with other genotypes. Coinfection with genotype G could enhance fibrosis under immunocompromised states. (HEPATOLOGY 2007;45:929–937.)

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. Supplementary material for this article can be found on the HEPATOLOGY website (http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).

Background/Aims: It is reported that some patients with undetectable hepatitis B surface antigen (HBsAg) have serum hepatitis B virus (HBV) DNA in patients with chronic hepatitis C (HCV). The aim of this study was to elucidate the impact of occult HBV infection on the efficacy and prognosis of interferon‐α (IFN) therapy in HCV patients. Methods: One hundred and forty HCV patients without HBsAg who received IFN therapy were studied. Serum HBV DNA was quantified by real‐time detection polymerase chain reaction. Results: Of 140 patients, 11 (7.9%) were HBV DNA‐positive before IFN therapy. The serum HBV DNA levels ranged from 106 to 884 copies/ml. Four of these 11 patients showed a sustained virologic response by IFN, compared with 39 of 129 without HBV DNA (P=NS). Interestingly, two of the 11 patients developed hepatocellular carcinoma (HCC) after therapy, compared with 16 of 129 without HBV DNA (P=NS). In the serial study, serum HBV DNA was transiently undetectable during and after IFN; however, most became positive during follow‐up. Conclusions: Occult HBV infection may not have a significant impact on response to IFN therapy for chronic HCV and development of HCC after therapy. Occult HBV may be sensitive to IFN although HBV is not completely eradicated.

Nucleic acid amplification‐based methods are used for confirmation of viremia in antibody to hepatitis C virus (anti‐HCV)‐positive patients. However, this technology is labor intensive, time consuming, requires complex laboratory conditions, and expensive. The aim of this study was to evaluate the sensitivity and specificity of the HCV core antigen (HCVcAg) assay as an alternative approach for confirmation of viremia in HCV‐infected subjects with HCV genotype 1–4. Two hundred forty‐six asymptomatic HCV RNA‐ positive donors were enrolled in this study, consisting of 122 blood donors from Egypt (116 with genotype 4, 4 with genotype 1, and 2 with 1 + 4 genotypes), 109 from Japan (85 with genotype 1, and 24 with genotype 2), and 15 from Uzbekistan (all with genotype 3). A total of 234 (95.1%) of 246 RNA‐positive specimens were detected by the HCVcAg assay; the sensitivity of HCVcAg assay consisted 93.4, 100, 100, and 94.8% for genotypes 1, 2, 3, and 4, respectively in comparison with RT‐PCR assay. The specificity of the assay was confirmed in the absence of the false‐positive results among 53 anti‐HCV‐negative, but anti‐Schistosoma mansoni (anti‐Sm) positive donors from Egypt. A positive correlation between HCVcAg and HCV RNA concentration levels (r = 0.671, P < 0.05) was observed among specimens with HCV genotype 4. The mean HCVcAg level was significantly lower in specimens with genotype 4 (2,935 fmol/L) comparing to genotypes 1, 2, and 3 (5,034, 4,962, and 4,740 fmol/L, respectively). No specific mutation was found in the core‐encoding region of the studied specimens. In conclusion, HCVcAg is shown to be specific, sensitive, and informative qualitative index for HCV viremia in asymptomatic carriers. J. Med. Virol. 73:216–222, 2004.