Inter-genotypic recombinant hepatitis C virus strains in Japan noted by discrepancies between immunoassay and sequencing.

Genetic recombination plays a significant role in the survival and evolution of hepatitis C virus (HCV), but methodological limitations have hindered the exploration of genetic recombination. HCV serotypes were evaluated in 104 patients with chronic hepatitis C when they initially presented in hospitals. Subsequently, HCV genotypes were analyzed using primers for core gene and NS5B gene. Near-complete nucleotide sequences of eight HCV isolates from two suspected patients with 2b/1b recombinant HCV were analyzed by amplification of nine overlapping regions of HCV-specific oligonucleotide primers at different time points: (i) at the first admission; (ii) before and (iii) after interferon therapy; and (iv) after development of hepatocellular carcinoma. The nucleotide sequence of eight HCV isolates obtained was 9,321-9,471 nucleotides in length, comprising a single ORF (polyprotein of 3,014 amino acids.) and segregated into discordant genotypes of 2b and 1b HCV with a recombination junction in NS2. This study highlights the need for more precise characterization of HCV in clinical samples where there is a discrepancy between immunoassays and sequencing. It also demonstrates the circulation of novel inter-genotypic recombinant HCV in Japan, because the cross over point of 2b/1b recombinant HCV in eight clinical isolates of these two patients differed from previously reported HCV recombinant from the Philippines and Japan.

B-cell-activating factor affects the occurrence of thyroid autoimmunity in chronic hepatitis C patients treated with interferon alpha.

Chronic hepatitis C (CHC) patients frequently suffer from thyroid disorders during interferon therapy. However, the mechanism remains unclear. In this study, we investigated the association between serum B-cell-activating factor belonging to the TNF family (BAFF) levels and the presence of antithyroid peroxidase antibody (anti-TPO) in CHC patients treated with pegylated interferon alpha and ribavirin combination therapy. Six months after the therapy, anti-TPO antibody was detected in 10 (males, 1; females, 9) of 50 patients. The mean age of these patients was higher than that of the anti-TPO-negative patients (61 yr versus 55 yr). Before treatment, the serum BAFF levels of the anti-TPO-positive patients were higher than those of the anti-TPO-negative patients. After starting therapy, the serum BAFF levels of both the anti-TPO-positive and -negative patient groups were elevated. Our findings suggest that the serum BAFF concentration before therapy can predict the risk of thyroid autoimmunity in elderly female patients with CHC.

High prevalence of antibodies to hepatitis A and E viruses and viremia of hepatitis B, C, and D viruses among apparently healthy populations in Mongolia.

The prevalence of infection with hepatitis A virus (HAV), HBV, HCV, HDV, and HEV was evaluated in 249 apparently healthy individuals, including 122 inhabitants in Ulaanbaatar, the capital city of Mongolia, and 127 age- and sex-matched members of nomadic tribes who lived around the capital city. Overall, hepatitis B surface antigen (HBsAg) was detected in 24 subjects (10%), of whom 22 (92%) had detectable HBV DNA. Surprisingly, HDV RNA was detectable in 20 (83%) of the 24 HBsAg-positive subjects. HCV-associated antibodies were detected in 41 (16%) and HCV RNA was detected in 36 (14%) subjects, none of whom was coinfected with HBV, indicating that HBV/HCV carriers account for one-fourth of this population. Antibodies to HAV and HEV were detected in 249 (100%) and 28 (11%) subjects, respectively. Of 22 HBV DNA-positive subjects, genotype D was detected in 21 subjects and genotype F was detected in 1 subject. All 20 HDV isolates recovered from HDV RNA-positive subjects segregated into genotype I, but these differed by 2.1 to 11.4% from each other in the 522- to 526-nucleotide sequence. Of 36 HCV RNA-positive samples, 35 (97%) were genotype 1b and 1 was genotype 2a. Reflecting an extremely high prevalence of hepatitis virus infections, there were no appreciable differences in the prevalence of hepatitis virus markers between the two studied populations with distinct living place and lifestyle. A nationwide epidemiological survey of hepatitis viruses should be conducted in an effort to prevent de novo infection with hepatitis viruses in Mongolia.

Full-length sequences of six hepatitis E virus isolates of genotypes III and IV from patients with sporadic acute or fulminant hepatitis in Japan.

OBJECTIVE: Ranges of variation and conservation in sequence need to be defined for detecting and genotyping hepatitis E virus (HEV). METHODS: Six HEV isolates from Japanese patients were sequenced over the entire genome and compared phylogenetically along with 16 reported HEV isolates, including two from pigs. RESULTS: Three of the six HEV isolates were of genotype III, and the remaining three were of genotype IV. Local clusterings of Japanese HEV isolates were observed in the phylogenetic analyses, including a swine HEV isolate reported previously (swJ570). All six HEV isolates possessed three open reading frames (ORFs). The ORF3 in the three isolates of genotype III were in a different reading frame, while that in the three isolates of genotype IV were in the same reading frame as ORF1. A stretch of 46-96 nucleotides was identified, point mutations and deletions in which were specific for the four genotypes (I-IV). A polymerase chain reaction method was developed with 9 nested universal primers, deduced from conserved regions in the 5'-terminal sequences of the 22 HEV genomes. CONCLUSIONS: Conserved and genotype-specific variation in HEV sequences, identified in the comparison of 22 full-length genomes, would be useful in designing primers for sensitive detection and specific genotyping of HEV RNA.

Lack of epidemiological evidence for a role of resolved hepatitis B virus infection in hepatocarcinogenesis in patients infected with hepatitis C virus in Japan.

OBJECTIVE: The role of resolved hepatitis B virus (HBV) infection in promoting hepatocellular carcinoma (HCC) in patients infected with hepatitis C virus (HCV) in Japan was evaluated by epidemiological surveys. METHODS: Antibody to hepatitis B core (anti-HBc) was determined in age-matched blood donors, and the frequency was compared with that in patients with HCV-associated HCC in Japan. RESULTS: Anti-HBc was detected significantly more frequently in the blood donors with than without antibody to HCV (anti-HCV; 76/135 or 56.3% vs. 65/255 or 25.5%, p < 0.001). In the patients with HCV-associated HCC, anti-HBc was detected in 109 of 202 (54.0%), which was comparable to the frequency in anti-HCV-positive blood donors (56.3%). Among the blood donors with anti-HCV, the prevalence of anti-HBc was no different between those with and without HCV RNA in serum (40/77 or 51.9% vs. 36/58 or 62.1%). CONCLUSIONS: The individuals of an age with high cancer frequency (>or=40 years) in Japan would have been exposed to HBV frequently (>50%), whether or not they have developed HCV-associated HCC. Despite repeated assertions in the literature, no epidemiological evidence was obtained for a role of past HBV infection in hepatocarcinogenesis in patients infected with HCV in Japan.

Natural histories of hepatitis C virus infection in men and women simulated by the Markov model.

The Markov model was introduced to simulate natural histories of hepatitis C virus (HCV) infection in men and women. The data set was constructed on 942 HCV carriers who were examined at least once a year without receiving antiviral therapies. Based on 2,251 patient-year data, the probabilities of transition between any two of the four clinical states, i.e., asymptomatic carrier state, chronic hepatitis, liver cirrhosis and hepatocellular carcinoma in 1 year were calculated. Hepatocellular carcinoma was defined as the absorbing state from where no transitions occur. Probability matrices thus obtained on six each subsets of HCV infection (asymptomatic carrier state, chronic hepatitis and liver cirrhosis in men and women) in their forties, fifties, and sixties, were used to simulate long-term outcomes of HCV infection. Male asymptomatic carriers aged 40 years were expected to retain the asymptomatic carrier state in 2.6%, evolve into chronic hepatitis in 48.4%, liver cirrhosis in 14.6% and hepatocellular carcinoma in 34.4% after 30 years when they reached 70 years of age, in contrast to 1.9%, 45.3%, 32.8% and 20.0%, respectively, of female asymptomatic carriers. Likewise, male patients with chronic hepatitis aged 40 years were expected to remain with chronic hepatitis in 43.8%, evolve into liver cirrhosis in 15.0% and hepatocellular carcinoma in 41.1%, contrasting with 38.9%, 32.7% and 22.0%, respectively, of female patients during 30 years. The Markov model could simulate the outcomes of 153 HCV carriers identified among blood donors after 5 years. The Markov simulation would help in assessing the long-term outcome of HCV infection and making decisions in the management of HCV carriers toward prevention of hepatocellular carcinoma.

Precore and core promoter mutations, hepatitis B virus DNA levels and progressive liver injury in chronic hepatitis B.

BACKGROUND/AIMS: To elucidate the viral factors responsible for progressive liver injury in chronic hepatitis B. METHODS: We analyzed 179 persistently infected patients (21 asymptomatic carriers, 126 with chronic hepatitis and 32 with cirrhosis) with genotype C hepatitis B virus (HBV). HBeAg/anti-HBe, levels of HBV DNA, mutations in the basic core promoter (BCP) region at nucleotides 1762/1764 and mutation in the precore (preC) region at nucleotide 1896 were determined. Serial samples from 18 patients also were analyzed. RESULTS: HBeAg/anti-HBe and HBV DNA levels per se were not related to liver fibrosis. The frequency of BCP mutations increased with progression of liver fibrosis. Although the preC mutation was detected more often among the LC group, the role of this mutation in progression of fibrosis seems less than that of the BCP mutations. Sequential analysis showed that (1) rapidly progressing cases were positive continuously for double mutations in the BCP with a wild-type precore sequence, and (2) asymptomatic cases with anti-HBe acquired the preC mutation during their clinical course. CONCLUSIONS: Double mutations in the BCP region at nucleotide 1762/1764 are closely related to progression of chronic liver disease. Acquisition of mutation in the preC region at nucleotide 1896 may contribute to inactivation of chronic liver disease.

Genetic heterogeneity of hepatitis E virus recovered from Japanese patients with acute sporadic hepatitis.

The recent discovery of a presumably Japan-indigenous hepatitis E virus (HEV) strain (JRA1) spurred analysis of additional isolates from 7 cases of acute sporadic hepatitis E infection. Comparison of a 326-nucleotide region from open-reading frame 1 indicated that 1, 3, and 3 isolates segregated to genotypes I, III, and IV, respectively. Six patients had not traveled abroad recently. One patient had traveled to Hawaii 1 month before becoming ill, and the nucleotide sequence of the HEV isolate infecting her resembled those of US isolates (89%-91% nucleotide identity). However, the isolate was even more homologous to 2 other Japanese isolates (95%-97% nucleotide identity), suggesting that it is more likely a domestic, rather than an imported, strain. Three genotype IV isolates from Japan also had a higher homology to each other (100% amino acid identity) than to 2 Chinese isolates (97%-98% amino acid identity). These findings suggest that HEV strains of at least 3 different genotypes have already made inroads and are spreading in Japan.