High prevalance of TT virus infection in Japanese patients with liver diseases and in blood donors

BACKGROUND/AIMS

Although a novel DNA virus, TT virus (TTV), has been isolated from a patient with cryptogenic post-transfusion hepatitis, its pathogenic role remains unclear. To elucidate its prevalence and clinical impact in patients with liver diseases, the presence of TTV DNA was assessed in patients with liver diseases and blood donors (BDs) in Japan using two primer sets, one conventional and the other new and highly sensitive.

METHODS

We studied 261 samples, 72 with chronic hepatitis associated hepatitis C virus (HCV-CH), 57 with hepatocellular carcinoma associated HCV (HCV-HCC), 12 with HCC without either HCV or hepatitis B virus (NBNC-HCC), and 120 of BDs.

RESULTS

Using two primer sets, TTV DNA was detected in 68 (94.4%), 53 (93.0%), 12 (100%), and 98 (81.7%) HCV-CH, HCV-HCC, NBNC-HCC, and BDs, respectively. The prevalence was not significantly different between HCV-CH and HCV-HCC, or between HCV-HCC and NBNC-HCC. Comparison between patients with and without TTV revealed no significant differences in backgrounds or biochemical findings. Histopathological findings in patients with HCV-CH, and number, maximum diameter, and histological differentiation of HCC also did not demonstrate any relation to TTV infection. TTV strains can be divided into five groups using phylogenetic analysis, but no disease-specific group appears to exist.

CONCLUSIONS

Our data suggest that: 1) TTV is very prevalent among patients with liver diseases and even among BDs in Japan, 2) TTV infection does not impact on liver damage with HCV infection, and 3) TTV infection also does not affect the development or progression of HCC.

TT virus infection among IVDUs in south western China

To elucidate the prevalence and clinical implications of infection with the newly described TT virus (TTV) among intravenous drug users (IVDUs) in Yunnan, southwest China, serum samples from 158 IVDUs (129 M, 29 F; mean age 26.1 +/- 5.5 years) were examined for TTV DNA by semi-nested polymerase chain reaction (PCR) using primers derived from the open reading frame (ORFI) of TTV DNA. The seroprevalence of viral markers of HIV, HBV, HCV and GB virus C/hepatitis G virus (GBV-C) infection was also examined. A molecular evolutionary analysis was performed. Thirty one (20%) of the IVDUs were positive for TTV DNA, and 34 (22%), 6 (4%), 98 (62%), 76 (48%), 136 (86%) and 65 (41%) were positive for anti-HIV, HBsAg, anti-HBs, anti-HBc, anti-HCV and GBV-C RNA, respectively. When all the subjects were classified according to TTV DNA positivity, no significant differences were observed in demographic, biochemical or virological characteristics between the 2 groups. TTV infection was in all cases associated with co-infection with 1 or more of the other aforementioned viruses. There were no significant differences in the various combinations of co-infection between TTV positive and negative groups. Phylogenetic analysis revealed that the TTV isolates obtained in the study could be grouped mainly into TTV genotype 1, and that some of the isolates belonged to subgroups other than those previously described. These results indicate that: 1) TTV infection is prevalent among IVDUs in China; 2) TTV probably has minor liver pathogenicity; and 3) new subgroups of genotype 1 and 2 exist in China.

Mutation patterns for two flaviviruses: hepatitis C virus and GB virus C/hepatitis G virus

We studied the mutation patterns of hepatitis C virus (HCV) and GB virus C/hepatitis G virus (HGV). Although the mutation patterns of the two viruses were similar to each other, they were quite different from that of HIV. In particular, the similarity of the patterns between HCV or HGV and human nuclear pseudogenes was statistically significant whereas there was no similarity between HIV and human nuclear pseudogenes. This finding suggests that the mutation patterns of HCV and HGV are similar to the patterns of spontaneous substitution mutations of human genes, implying that nucleotide analogues which are effective against HCV and HGV may have a side effect on the normal cells of humans.

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.

Amino acid substitutions in NS5A region of GB virus C and response to interferon therapy

GB virus C (GBV-C) is related to hepatitis C virus (HCV) and has a similar genomic structure. Some predictors for the efficacy of interferon (IFN) therapy on HCV have been reported: genotype, viral load, IFN dose, and the amino acid substitutions in the NS5A region, designated as the interferon sensitivity determining region (ISDR). To evaluate the correlation between the amino acid substitutions in the GBV-C NS5A region and the response to IFN therapy, single-strand conformation polymorphism (SSCP) analysis was performed in the 12 concomitantly GBV-C-and HCV-infected patients who received IFN therapy at three time points: before, end-point, and after the IFN therapy. The region in the GBV-C NS5A studied includes the amino acids that exhibit some homology to the ISDR and the various substitutions. By SSCP analysis, amplicons were separated into 1-4 bands, which indicated the existence of heterogeneity in each host. However, the deduced amino acid sequences in these bands exhibited no characteristic differences among these strains irrespective of response to IFN therapy. Of the 32 strains separated by SSCP, 7 strains were responders, and 25 were nonresponders. The mean amino acid substitution, compared with the consensus sequence of nonresponders, was 1.00+/-0.93 among responders, and 1.40+/-0.85 among non-responders (P= NS). No correlation between the amino acid sequence in the GBV-C NS5A region and response to IFN therapy was found, indicating that the GBV-C NS5A region dose not act as the ISDR.

Amino acid substitutions in NS5A region of GB virus C and response to interferon therapy

GB virus C (GBV-C) is related to hepatitis C virus (HCV) and has a similar genomic structure. Some predictors for the efficacy of interferon (IFN) therapy on HCV have been reported: genotype, viral load, IFN dose, and the amino acid substitutions in the NS5A region, designated as the interferon sensitivity determining region (ISDR). To evaluate the correlation between the amino acid substitutions in the GBV-C NS5A region and the response to IFN therapy, single-strand conformation polymorphism (SSCP) analysis was performed in the 12 concomitantly GBV-C-and HCV-infected patients who received IFN therapy at three time points: before, end-point, and after the IFN therapy. The region in the GBV-C NS5A studied includes the amino acids that exhibit some homology to the ISDR and the various substitutions. By SSCP analysis, amplicons were separated into 1-4 bands, which indicated the existence of heterogeneity in each host. However, the deduced amino acid sequences in these bands exhibited no characteristic differences among these strains irrespective of response to IFN therapy. Of the 32 strains separated by SSCP, 7 strains were responders, and 25 were nonresponders. The mean amino acid substitution, compared with the consensus sequence of nonresponders, was 1.00+/-0.93 among responders, and 1.40+/-0.85 among non-responders (P= NS). No correlation between the amino acid sequence in the GBV-C NS5A region and response to IFN therapy was found, indicating that the GBV-C NS5A region dose not act as the ISDR.

TT virus infection among blood donors and patients with non-B, non-C liver diseases in Korea

BACKGROUND/AIMS

A novel virus, designated the TT virus (TTV), was isolated from the serum of a patient with posttransfusion hepatitis of unknown etiology, in Japan. Subsequently, TTV was suggested to be a causative agent in a proportion of cases with cryptogenic hepatitis in Japan. This study aimed to elucidate the significance of TTV infection in cases with cryptogenic liver disease in Korea, a neighbor of Japan.

METHODS

The prevalence of TTV infection was studied in 120 patients with liver diseases, including 85 patients diagnosed as having non-B, non-C liver diseases. As controls, 220 blood donors were also examined. TTV DNA was detected by polymerase chain reaction, and the sequence was analyzed by phylogenetic analysis.

RESULTS

Fourteen (14.0%) of 100 accepted blood donors, 23 (19.2%) of 120 rejected blood donors, and 15 (17.6%) of 85 patients with non-B, non-C liver diseases were positive for TTV DNA. The prevalences of TTV infection among these groups were not significantly different. Phylogenetic analysis suggested the existence of four major genotypes of TTV The proportions of each genotype among patients with non-B, non-C liver diseases were not different from those among accepted blood donors.

CONCLUSIONS

TTV exists in Korea, but the prevalence among patients with non-B, non-C liver diseases was almost the same as that among blood donors. TTV may not be the main causative agent of cryptogenic liver disease in Korea. The relationship between non-B, non-C liver diseases and TTV genotype remains unclear, although TTV can be classified into four genotypes.

A new genotype of TT virus (TTV) infection among Colombian native Indians

Serum TTV DNA was assayed in 140 native Indians and 40 members of the general population in Colombia to determine the prevalence of TT virus (TTV) infection among Colombian native Indians. Of the 140 native Indians, 23 (16.4%) were positive for TTV DNA, compared to 4 (10.0%) of 40 from the general population (P = not significant). The prevalence of TTV DNA among native Indians was much higher than that of HBsAg and anti-HCV. Comparison of subjects with and without TTV DNA revealed no significant differences in all characteristics between the two groups. A phylogenetic tree, using the open reading frame 1 sequence (222 bp), indicated that the virus could be classified into four different genotypes, including three previously reported ones. The results show that TTV infection is common in Colombian native Indians without liver disease and also indicate the existence of a novel genotype of TTV.

GB virus C/hepatitis G virus infection among patients with hepatocellular carcinoma in the inshore area of the Yangtze River, China

To investigate the association between GB virus C/hepatitis G virus (GBV-C/HGV) infection and the development of hepatocellular carcinoma (HCC) in H city, in the inshore area of the Yangtze River, where high prevalence of HCC has been reported, we determined hepatitis B virus (HBV) and hepatitis C virus (HCV) markers, GBV-C/HGV-RNA and GBV-C/HGV E2 antibody (anti-HG E2) among 114 HCC patients and the same number of age- and sex-matched controls. There were no significant differences in the clinical and demographic characteristics between them, except for serum alanine aminotransferase level and history of liver diseases. There was a significant difference of hepatitis B virus surface antigen (HBsAg) prevalence between the HCC patients (75.4%) and the controls (20.2%; P<0.01). Hepatitis C virus antibody was detected in 4.4% of the HCC patients, compared with 1.7% of the controls. GB virus-C/HGV-RNA and anti-HG E2 were detected in 14.9 and 1.7% of the HCC patients, respectively, compared with 7.0 and 1.7% of the controls, respectively. Nucleotide sequences and molecular evolutionary analysis showed the strains of GBV-C/HGV-RNA were classified into genotype 2 and 3 (HG and ASIA type). An effect analysis showed an odds ratio (OR) for developing HCC from GBV-C/HGV infection among HBsAg-positive subjects was 14.9, with a 95% CI of 4.9-45.4. HBsAg infection alone was 13.83 (95% CI 7.4-25.9) and GBV-C/HGV infection alone, 3.74 (95% CI 1.1-13.1), respectively. These data indicate that HBV infection is considered to be one of the major risk factors in patients with HCC and although GBV-C/HGV infection was observed in both the HCC and the control groups, it might not play an important role in the development of HCC in this area.

New genotypes of TT virus (TTV) and a genotyping assay based on restriction fragment length polymorphism

A phylogenetic analysis, using the open reading frame I sequence of 93 TT viruses (TTV) obtained from various geographical areas, indicated that the virus could be classified into six different genotypes including three hitherto unreported genotypes. The high reliability of the six clusters was confirmed by bootstrap analysis. On the basis of these sequence data, a new simple genotyping assay based on a restriction fragment length polymorphism of TTV was developed. Using the enzymes NdeI and PstI, followed by cleavage with NlaIII or MseI, it was possible to distinguish between the six TTV genotypes. This system will provide the framework for future detailed epidemiological and clinical investigations.

GB virus C/hepatitis G virus infection among Colombian native Indians

To elucidate the prevalence of GB virus C/hepatitis G virus (GBV-C/HGV) infection in Colombian native Indians, serum GBV-C/HGV RNA was assayed in 163 native Indians and 67 members of the general population in Colombia. The native Indians (males:females = 40:123) and the members of the general population (males:females = 20:47) were tested by reverse transcription-semi-nested polymerase chain reaction. Of the 163 native Indians, 10 (6.1%) were positive for GBV-C/HGV RNA, compared with one (1.5%) of 67 from the general population. All Indians were negative for hepatitis B surface antigen and antibody to hepatitis C virus. Of 10 Indians with GBV-C/HGV RNA, the genotype of nine subjects was the Asian type. These data indicated that 1) the prevalence of GBV-C/HGV RNA in Colombian native Indians is high, and 2) GBV-C/HGV was probably brought from Asia and inherited for generations in some native Indian groups.

African origin of GB virus C/hepatitis G virus

Ninety-four GB virus C/hepatitis G virus (GBV-C/ HGV) RNA-positive serum samples were obtained from all over the world. We found that all 15 GBV-C/HGV isolates from the Pygmies and the Bantu in the Central African region had a 12-amino acid indel (i.e. insertion or deletion) in the non-structural protein (NS) 5A region. Phylogenetic analyses of the NS5A region, using GBV-A as an outgroup, showed that these 15 isolates had diverged from the common ancestor much earlier than the remaining isolates, indicating an African origin of GBV-C/HGV.

Genotype of GB virus C/hepatitis G virus by molecular evolutionary analysis

GB virus C/hepatitis G virus is a newly described virus. Classification of GB virus C/hepatitis G virus into genotypes has not been established. We analyzed nucleotide sequences within the 5' untranslated region of GB virus C/hepatitis G virus isolates and segregated these isolates into genotypes. Twenty serum samples with GB virus C/hepatitis G virus RNA from Australia, Cameroon, the Congo, Japan, Mongolia, and Bangladesh were studied. Reverse transcription and polymerase chain reaction were used to obtain GB virus C/hepatitis G virus RNA. After nucleotide sequences from the 5' untranslated region were determined, 68 nucleotide sequences, including 48 previously reported sequences, were analyzed by molecular evolutionary methods. The phylogenetic tree of the 5' untranslated region showed that all strains could be divided into three major genotypes, GB type (type 1), HG type (type 2), and Asian type (type 3). Bootstrap analysis indicated that the strains could be divided into three major genotypes but could not be further subdivided. Moreover, frequency histograms of pairwise distances between nucleotide sequences demonstrated only one peak. These result indicated that GB virus C/hepatitis G virus can be classified into three major genotypes, GB type (type 1), HG type (type 2), and Asian type (type 3), and should not be divided into minor subtypes.

Interferon-alpha therapy in patients dually infected with hepatitis C virus and GB virus C/hepatitis G virus--virological response of HGV and pretreatment HGV viremia level

BACKGROUND/AIMS

The response to interferon-alpha (IFN) therapy of recently isolated GB virus C and hepatitis G virus (HGV) is still unclear. To investigate the biochemical and virological response to IFN therapy in patients with chronic hepatitis C virus (HCV) infection concomitantly infected with HGV, 196 patients with HCV who had received IFN therapy were retrospectively studied.

METHODS

HGV and HCV RNA were detected by reverse transcription nested polymerase chain reaction (RT-PCR). Serum HGV RNA levels were quantified by competitive RT-PCR. The HGV genotype was detected by restriction fragment length polymorphism analysis using the PCR products.

RESULTS

Of 196 patients, 16 (8.2%) were positive for both HCV and HGV RNA before IFN therapy. There were no significant clinical and virological differences between the patients with dual infection and those with only HCV infection. During the therapy, a decrease or loss of serum HGV RNA level was observed in these patients. Six months after cessation of the therapy, five of 16 patients became negative for HGV RNA by RT-PCR. The pretreatment HGV RNA level of the patients who lost HGV RNA after cessation of IFN was low (median=10(3) copies/ml), compared to the level (median=10(7) copies/ml, p<0.01) in the patients with positive HGV RNA after the therapy. The HGV genotype of these 16 patients was the same type.

CONCLUSIONS

These data suggest that: 1) there is no significant difference in response to IFN therapy between patients with dual and single infection; 2) HGV shows sensitivity to IFN therapy; and 3) in the patients who show a low pretreatment HGV RNA level, serum HGV RNA becomes undetectable by RT-PCR after cessation of IFN therapy.

Effect of interferon-alpha and ribavirin therapy on serum GB virus C/hepatitis G virus (GBV-C/HGV) RNA levels in patients chronically infected with hepatitis C virus and GBV-C/HGV

GB virus C/hepatitis G virus (GBV-C/HGV) is a newly described virus associated with hepatitis in humans, and GBV-C/HGV coinfection is common in patients chronically infected with hepatitis C virus (HCV). To determine the clinical impact of GBV-C/HGV infection in such patients and the effect of interferon-alpha and ribavirin therapy on serum GBV-C/HGV RNA levels, GBV-C/HGV RNA was detected and quantitated in serum samples from 62 chronically infected HCV patients by a combination of a qualitative nested reverse transcription-polymerase chain reaction and a newly developed quantitative branched DNA assay: 10 patients were positive for serum GBV-C/HGV RNA. There were no differences in the clinical, biochemical, and histologic features of the patients with GBV-C/HGV-HCV coinfection compared with those with HCV infection alone. Interferon-alpha treatment caused a marked but usually transient reduction in serum GBV-C/HGV RNA, and ribavirin had, at most, a modest antiviral effect.

Three different GB virus C/hepatitis G virus genotypes. Phylogenetic analysis and a genotyping assay based on restriction fragment length polymorphism

The 5'-untranslated region (5'-UTR) sequences of 33 GB virus C/hepatitis G virus (GBV-C/HGV) obtained from different geographic areas were determined through reverse-transcription polymerase chain reaction and dideoxy chain termination sequencing, the alignment of sequences, the estimation of the number of nucleotide substitution per site, and construction of phylogenetic trees. The 5'-UTR of GBV-HGV was found to be heterogeneous, with 70.9-99.5% homology. Three distinct phylogenetic branches were observed consistently in all phylogenetic trees. GBV-C is the prototype for one, HGV for another, and there is a new branch which consisted of GBV-C/HGV isolates from Asia. Genotype-specific restriction sites for the restriction enzymes, ScrFI and BsmFI, were identified, and a simple restriction fragment polymorphism analysis was developed for genotyping. These data provide evidence that GBV-C/HGV consists of three different genotypes. Our simple genotyping assay will also provide a tool for epidemiological studies of GBV-C/HGV infection.

High prevalence of GB virus C/hepatitis G virus infection among the Jewish population in Uzbekistan

Although a new virus, GB virus C/hepatitis G virus (GBV-C/HGV), has been isolated from patients with hepatitis by two different research groups, its prevalence in the world and pathogenesis are still unknown. In this study, 92 samples from the Jewish population of Uzbekistan were investigated for the prevalence of GBV-C/HGV. GBV-C/HGV RNA was detected by reverse transcription polymerase chain reaction (RT-PCR) using specific primers derived from the 5'-untranslated region (5'-UTR). Sequences were analyzed by a molecular evolutionary method. Of 92 samples, GBV-C/HGV RNA was detected in ten (10.9%), HCV RNA was present in two (2.2%), and HBsAg in eight (8.7%). HTLV-I and HIV infection was not detected. Single GBV-C/HGV infection was detected in eight (80%), and co-infection with HBV or HCV was detected in only two of the GBV-C/HGV infections. Alanine aminotransferase (ALT) levels were elevated in three (3.3%), but none with single GBV-C/HGV infection had an elevated ALT level. Nine people (90%) with GBV-C/HGV infection were distributed under the mean age of the population (P < 0.05). Molecular evolutionary analysis showed all GBV-C/HGV strains in this study were related to the HGV derived from the US. These results indicate that (1) GBV-C/HGV infection is highly prevalent among the Jewish population in Uzbekistan; (2) single GBV-C/HGV infections without persistent hepatitis are common; and (3) GBV-C/HGV infection is present among the younger generation.

Interferon-alpha therapy for individuals with normal serum alanine aminotransferase levels before treatment

While interferon (IFN) therapy is approved for patients with chronic hepatitis C infection, the effectiveness of IFN therapy for anti-hepatitis C virus (HCV)-positive individuals with normal ALT levels remains poorly understood. Twenty-five individuals (M:F = 9:16; age = 51.8 +/- 15.1 years) who showed a normal alanine aminotransferase (ALT) level (< 30 IU/L) at least 6 months before treatment and were positive for both anti-HCV and serum HCV-RNA by reverse transcription polymerase chain reaction (RT-PCR) were studied. Of these, 16 received IFN therapy for 24 weeks (780 million units total IFN-alpha 2b) and nine were followed for 12 months as controls. The serum HCV-RNA level was determined by bDNA assay and HCV genotype was detected by enzyme immunoassay. All were shown to have chronic hepatitis by liver biopsy. Six (37.5%) of 16 individuals lost serum HCV-RNA by RT-PCR 6 months after cessation of therapy (complete response; CR), while the remaining individuals were defined as non-responders (NR). Of the six individuals in the CR group, five had HCV type 2 infection, compared with none of 10 individuals in the NR group (P < 0.01). There was a trend towards a lower pretreatment viraemia level in the CR group than in the NR group. These data suggest that IFN therapy for individuals with HCV type 2 infection and normal ALT levels was effective.

Constrained evolution with respect to gene overlap of hepatitis B virus

With the aim of elucidating the evolution of a hepadnavirus family, we constructed molecular phylogenetic trees for 27 strains of hepatitis B virus (HBV) using both the unweighted pair-grouping and neighbor-joining methods. All five gene regions, P, C, S, X, and preS, were used to construct the phylogenetic trees. Using the phylogenetic trees obtained, we classified these strains into five major groups in which the strains were closely related to each other. Our classification reinforced our previous view that genetic classification is not always compatible with conventional classification determined by serological subtypes. Moreover, constraints on the evolutionary process of HBV were analyzed for amino-acid-altering (nonsynonymous) and silent (synonymous) substitutions, because two-thirds of the open reading frame (ORF), P, contains alternating overlapping ORFs. In our unique analysis of this interesting gene structure of HBV, the most frequent synonymous substitutions were observed in the nonoverlapped parts of the P and C genes. On the other hand, the number of synonymous substitutions per nucleotide site for the S gene was quite low and appeared a strongly constrained evolution. Because the P gene overlaps the S gene in a different frame, the low rate of synonymous substitution for the S gene can be explained by the evolutionary constraints which are imposed on the overlapping gene region. In other words, synonymous substitutions in the S gene can cause amino acid changes in its overlapping region in a different frame. Thus, the evolution of HBV is constrained evolutionarily by the overlapping genes. We propose calling this mode of viral evolution "constrained evolution." The evolution of HBV represents a typical constrained evolution.

New hepatitis C virus (HCV) genotyping system that allows for identification of HCV genotypes 1a, 1b, 2a, 2b, 3a, 3b, 4, 5a, and 6a

Recent studies have focused on whether different hepatitis C virus (HCV) genotypes are associated with different profiles of pathogenicity, infectivity, and response to antiviral therapy. The establishment of a simple and precise genotyping system for HCV is essential to address these issues. A new genotyping system based on PCR of the core region with genotype-specific PCR primers for the determination of HCV genotypes 1a, 1b, 2a, 2b, 3a, 3b, 4, 5a, and 6a was developed. A total of 607 samples (379 from Japan, 63 from the United States, 53 from Korea, 35 from Taiwan, 32 from China, 20 from Hong Kong, 15 from Australia, 6 from Egypt, 3 from Bangladesh, and 1 from South Africa) were tested by both the assay of Okamoto et al. (H. Okamoto, Y. Sugiyama, S. Okada, K. Kurai, Y. Akahane, Y. Sugai, T. Tanaka, K. Sato, F. Tsuda, Y. Miyamura, and M. Mayumi, J. Gen. Virol. 73:673-679, 1992) and this new genotyping system. Comparison of the results showed concordant results for 539 samples (88.8%). Of the 68 samples with discordant results, the nucleotide sequences of the HCV isolates were determined in 23, and their genotypes were determined by molecular evolutionary analysis. In all 23 samples, the assignment of genotype by our new genotyping system was correct. This genotyping system may be useful for large-scale determination of HCV genotypes in clinical studies.

GB virus C/hepatitis G virus infection in southern China

The prevalence of GB virus C/hepatitis G virus (GBV-C/HGV) infection among intravenous drug users (IVDUs), patients with liver diseases, and blood donors in Nanning, southern China was studied. GBV-C/HGV RNA was detected by reverse transcription polymerase chain reaction with primers derived from the 5'-untranslated region. GBV-C/HGV RNA was detected in 64 of 85 IVDUs, 20 of 80 persons with liver disease, and 1 of 50 blood donors. Among IVDUs, GBV-C/HGV infection was associated with antibodies to hepatis C virus (HCV) and with hepatitis B surface antigen (HBsAg). Eleven nucleotide sequences were determined and analyzed by molecular evolutionary analysis. In a phylogenetic tree, the isolates were grouped in three clusters with GBV-C and HGV grouped in two clusters. These data indicate that GBV-C/HGV infection is common in China among IVDUs but uncommon among persons with liver disease without HBsAg or anti-HCV and that there is a new group of GBV-C/HGV.

GB virus C/hepatitis G virus infection among Japanese patients with chronic liver diseases and blood donors

Recently, a novel hepatitis virus, GB virus C/hepatitis G virus (GBV-C/HGV), has been isolated. To elucidate the seroprevalence of chronic GBV-C/HGV infection in Japan and the phylogenetic relationship between Japanese strains and the strains previously reported, serum GBV-C/HGV RNA was detected by reverse transcription polymerase chain reaction (RT-PCR) in 203 patients with chronic liver diseases and 200 samples of voluntary blood donors. RT-PCR was performed with primers derived from the 5'-untranslated region which were conserved between GBV-C and HGV and distant from other flaviviruses including hepatitis C virus (HCV). The nucleotide sequences were determined by the dideoxy chain termination method. The phylogenetic analysis was performed by the neighbor-joining method. In 10 (4.7%) of 203 patients with chronic liver diseases and in 1 (0.5%) of 200 blood donor samples, serum GBV-C/HGV RNA was detected. Of 10 patients, 9 patients were positive for anti-HCV and negative for HBsAg, and 1 patient was positive for HBsAg and negative for anti-HCV. The phylogenetic analysis indicated that there were three major groups which were group 1 (GBV-C), group 2 (HGV), and group 3 (a group of Japanese strains). These data indicated that (1) there was a low prevalence of GBV-C/HGV infection in Japanese patients with chronic liver diseases, (2) a high proportion of patients with GBV-C/HGV infection had chronic HCV infection however, and (3) there were at least three groups in strains of GBV-C/HGV.

Quantification of serum hepatitis C virus core protein level in patients chronically infected with different hepatitis C virus genotypes

BACKGROUND/AIM

A novel fluorescent enzyme immunoassay (FEIA) for the detection and quantification of serum hepatitis C virus (HCV) core protein was developed. The aim of this study was to evaluate the relation among serum HCV core protein level, HCV RNA level, and HCV genotype in patients with chronic HCV infection.

PATIENTS AND METHODS

Serum HCV core protein, HCV RNA, HCV genotype were determined in 175 patients using the FEIA, branched DNA assay (Quantiplex HCV RNA ver 1.0), and serologically defined genotyping assay, respectively. For the specificity, all 13 patients seronegative for anti-HCV were negative for serum core antigen and HCV RNA by FEIA and bDNA, respectively.

RESULTS

FEIA assay seems to be more sensitive than bDNA for patients with HCV type 2 infection (detection: 83.4% v 63.4%, p < 0.01). There was a good overall correlation between the FEIA and bDNA results. However, when the patients were stratified into their HCV types, a correlation was observed in HCV type 1 but not in type 2 infection. Patients with HCV type 2 infection had a lower serum HCV core protein level (median 56 RFI) compared with type 1 infection (median 149 RFI, p < 0.01). Thirty seven patients subsequently received interferon alpha therapy, patients who showed a complete and sustained response had a lower pretreatment serum HCV core protein level compared with patients who had a relapse and nonresponders (36 v 338 RFI, p < 0.01).

CONCLUSIONS

This study showed that FEIA (1) is a good assay for the detection and quantification of serum HCV core protein level, (2) is also very sensitive in detecting HCV core protein in patients with HCV type 2 infection, and (3) may have a role as a predictor of subsequent response to interferon therapy.

Possible prediction of adverse reactions to pyrimidine chemotherapy from urinary pyrimidine levels and a case of asymptomatic adult dihydropyrimidinuria

Deficiency of dihydropyrimidine dehydrogenase or dihydropyrimidinase, enzymes that catalyze the breakdown of pyrimidine chemotherapy agents such as 5-fluorouracil, may cause serious adverse reactions to these agents. We attempted to establish the reference range for urinary pyrimidines in adults to detect individuals with abnormal pyrimidine metabolism. We analyzed urinary pyrimidine levels in 1133 adults to establish a reference range for persons ages 20 years or older. Urinary dihydrouracil and uracil levels were determined by high-performance liquid chromatography with column switching. The reference range obtained was found to be 0-59.3 micromol/g creatinine for dihydrouracil and 0-129.8 micromol/g creatinine for uracil. In addition, an asymptomatic man with suspected dihydropyrimidinase deficiency was detected on the basis of dihydropyrimidinuria. Although only three cases of this disease have been found worldwide, including one infant reported previously by our group, it may not be so rare as has been thought. In this man, a 10 mg/kg oral uracil loading test yielded a peak blood dihydrouracil level of 192.1 micromol/liter and a peak uracil level of 67.8 micromol/liter. Eight h after loading, the uracil level was still 11.1 micromol/liter, about 17 times that in healthy subjects. Additional research on dihydropyrimininase deficiency may help to prevent adverse reactions to pyrimidine chemotherapy agents in susceptible individuals.

Case report: development of hepatocellular carcinoma in a patient with chronic hepatitis C infection after a complete and sustained response to interferon-alpha

A 60-year-old man with a chronic hepatitis C virus (HCV) infection and histological features of chronic active hepatitis was treated with interferon-alpha (IFN). He successfully responded to IFN with normalization of serum ALT and disappearance of serum HCV-RNA. His liver biochemistry profile remained normal and serum HCV-RNA was not detected throughout the entire follow-up period. One year later, a small hepatocellular carcinoma (HCC) was detected by routine ultrasonographic screening. Laparotomy revealed a small tumour with no metastasis and the non-tumorous liver demonstrated macronodular cirrhosis. Although no space-occupying lesions were detected by frequent radiological examinations prior to IFN therapy, the small size of the tumour suggested de novo development of HCC. Patients with chronic HCV infection, including those who have complete responses to IFN and lack clinical and histological evidence of cirrhosis, should be followed up for the potential development of HCC.