岡本 宏明

A nonenveloped, single-stranded, and circular DNA virus designated TT virus (STV) has been reported in association with hepatitis of unknown etiology. TN has a wide sequence divergence (similar to 52%), by which it is classified into at least 16 genotypes separated by an evolutionary distance of >0.30. Therefore, the detection of TTV DNA by polymerase chain reaction would be influenced by primers deduced from conserved or divergent regions of the genome. Of the 30 sera from healthy individuals, up to 17% tested positive with primers deduced from coding region, much less frequently than up to 93% testing positive with primers from noncoding region. These differences were not attributable to the sensitivity of detection, because a cloned TTV DNA of genotype la was detected sensitively (up to 1 copy per test) with primers deduced from either the coding or the noncoding region of the same genotype. Sera testing positive only with noncoding region primers, or those showing higher titers with noncoding than coding region primers, contained TN DNA strains with sequence divergence of 47-53% from the TA278 isolate of genotype la within the N22 region spanning 222-231 nucleotides. Some of the sera contained two or three TTV DNA strains of distinct genotypes. These results indicate TTV strains with extremely high sequence divergence prevailing in healthy individuals and frequent mixed infection with TN strains of distinct genotypes. (C) 1999 Academic Press.

A nonenveloped and single-stranded DNA virus designated TT virus (TTV) has been reported from Japan in association with hepatitis of unknown etiology. Very recently, the prototype TTV isolate (TA278) of genotype 1 is proven to have a circular genome with 3852 nucleotides. A TTV isolate (TUS01) was recovered from a blood donor in the United States, and its entire circular nucleotide sequence of 3818 nucleotides was determined. It possessed two open reading frames coding for 761 and 156 amino acids, respectively. TUS01 shared 60.5% of the nucleotide sequence with the TA278 isolate from Japan that was longer by 35 nt. The sequence of the noncoding region of 1203 nt was conserved with a similarity of 83.4%. Sequence preservation was much lower for the two open reading frames; nucleotide and amino acid sequences were 54.8 and 37.0% similar, respectively, for one and 55.5 and 38.8% similar for the other. By comparison of a partial sequence of 222 nucleotides among 239 TTV isolates available from various countries, at least 11 genotypes with sequence divergence of >30% were recognized. TUS01 was deduced to be of genotype 11, which has not been reported before. Conserved sequences in the noncoding region could be used as primers for sensitively detecting TTV DNA by polymerase chain reaction. Divergent sequences in coding regions would be useful as primers for distinguishing various TTV genotypes. (C) 1999 Academic Press.

An unenveloped DNA virus named TT virus (TTV) has been reported in association with acute and chronic hepatitis of unknown etiology. The effect of interferon on TTV was evaluated in the patients with chronic hepatitis C who were coinfected with TTV. TTV DNA was determined by a polymerase chain reaction with heminested primers in the 96 patients with chronic hepatitis C who received interferon-alpha (516 million units in 26 weeks) and followed for 24 months thereafter. TTV DNA was detected in 31 (32%) patients before therapy. TN DNA became undetectable during interferon therapy and remained absent in 14 (45% of the 31 patients) through 24 months thereafter. The four patients with pretreatment TN DNA titer greater than or equal to 10(3)/ml did not respond. These results indicate that TTV is sensitive to interferon, and the response would be inversely correlated with pretreatment viral titers. (C) 1999 Wiley-Liss, Inc.

An ELISA was developed for serological determination of the six genotypes of hepatitis B virus (HBV) designated A, B, C, D, E, and F. Monoclonal antibodies were raised against genotype-specific epitopes in the preS2-region product, and labeled with horseradish peroxidase. Hepatitis B surface antigen (HBsAg) in sera was captured by immobilized antibodies against the common determinant, and evaluated for reactivity with genotype-specific monoclonal antibodies labeled with the enzyme. Serological genotyping was in complete accord with genotypes determined by S-gene sequences in a panel of 68 sera containing HBV/HBsAg of different;genotypes. Of 514 sera with HBsAg from Japan, 507 (98.6%) were genotyped serologically: genotype A was identified in 24 (4.7%), B in 196 (38.1%); C in 282 (54.9%); D in 2 (0.4%); and F in 3 (0.6%). There were no sera containing HBV of genotype E. Likewise, 425 of 446 (95.3%) sera with HBsAg from Brazil, China, India, Indonesia, Kenya, Korea, Nepal, Papua New Guinea, the Philippines, and Thailand were classified into A (25.6%), B (24.2%), C (33.9%), and D (11.7%) genotypes; there were no sera-with HBsAg of genotype E or F among them. Some sera unclassifiable by ELISA revealed mixed infection with HBV of distinct genotypes, or contained HBsAg deprived of genotype-specific epitopes by point mutations. The ELISA would be useful for large-scale surveys, because it allows serological detection of HBV genotypes without sequencing nucleotides. (C) 1999 Elsevier Science B.V. All rights reserved.

Recently, an unenveloped, single-stranded DNA virus named TT virus (TTV) has been reported in association with hepatitis of non-A-G etiology. Five patients with TTV viremia, who received bile drainage or cholecystectomy, were tested for TTV DNA in bile by polymerase chain reaction with heminested primers. TTV DNA was detected in bile from all patients; titers were 10-100 times higher than in serum in 4 and at a comparable level in the remaining 1 patient. TTV DNA was detected in feces, also, in 1 of the 2 patients tested. The buoyant density of TTV in bile from I tested patient (1.33-1.35 g/cm(3)) was the same as that in feces (1.32-1.35 g/cm(3)). TTV may be secreted via bile into feces in a transmissible form and would spread by a fecal-oral route for deep and wide penetration into the general population.

BACKGROUND: An unenveloped, single-stranded DNA virus named TT virus has been found in association with elevated alanine aminotransferase (ALT) levels in recipients of transfusions and has been detected frequently in patients with acute or chronic hepatitis of non-A to -G etiology in Japan. DNA of the TT virus was searched for in blood donors with or without elevated ALT levels. STUDY DESIGN AND METHODS: A total of 861 blood donors without previous transfusions and who were negative for markers of hepatitis B or C virus infection were tested. DNA of the TT virus was detected by polymerize chain reaction with hemi-nested primers. RESULTS: TT virus DNA was detected in 62 of 280 (22.1% [95% CI: 18.1-26.6]) donors with elevated ALT levels (mean +/- SD, 89.3 +/- 36.4 U/L; range, 61-301 U/L), which is significantly more frequently (p<0.02) than its detection in 91 of 581 (15.7% [95% CI: 13.2-18.4]) donors with normal ALT (less than or equal to 45 U/L). The frequency of TT virus DNA increased with age, in donors with and without elevated ALT. CONCLUSION: The detection of TT virus DNA, at a frequency higher in donors with elevated ALT than in those without, strengthens the association of TT virus with non-A to -G hepatitis.

It remains controversial if hepatitis C virus (HCV) genotypes in the same genetic group or type are different in the activity of viral replication and capacity to induce severe clinical disease. HCV genotypes and HCV RNA titers were determined in consecutive 264 patients with chronic liver disease in Yamaguchi. Japan. Genotype I/1a was detected in 3 (1%), II/1b in 192 (74%). III/2a in 46 (18%), IV/2b in 17 (6%) and co-infection with Il/1b and III/2a in 3 (1%); HCV RNA titers in the remaining three patients were too low to be genotyped. The patients with genotype III/2a were significantly older (P < 0.05) and had lower HCV RNA titers in serum than those with genotype IV/2b (P = 0.0211: odds ratio 6.47 [95% confidence interval. 1.323-31.587]). These results indicate that, even though genotypes III/2a and IV/2b belong to the same genetic group (type) 2, they would need to be distinguished clinically because the patients' age and HCV RNA titer in serum are both important factors in treating the patients with HCV infection. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.

In 1997, a novel DNA virus was isolated from the serum of a patient with posttransfusion hepatitis of unknown etiology in Japan, and it was named TT virus (TTV) after the initials of the index patient. TTV is a nonenveloped, single-stranded and circular DNA virus, and its entire sequence of similar to 3.9 kb has been determined, For being a DNA virus, TTV has a wide range of sequence divergence, allowing the classification into at least 16 genotypes separated by a sequence difference of >30% from one another, The nucleotide sequence of the noncoding region of the TTV genome is conserved, whereas that of the coding region is highly variable, TTV strains with extremely high sequence divergence are common in the same individuals, thereby indicating a mixed infection of TTV strains of different genotypes, An association is found between hepatitis of unknown etiology and the TTV genotypes which are detectable by PCR with primers deduced from the N22 region (genotype 1) in the open reading frame 1 encoding the capsid protein, It would be important to select the primers for specific detection of the TTV genotypes associated with clinical diseases, to further evaluate the capacity of TTV to induce acute and chronic liver disease as well as extrahepatic manifestations.

TT virus (TTV) is a nonenveloped, single-stranded DNA virus with little sequence homology to known viruses, and associated with elevated transaminase levels in the patients with posttransfusion hepatitis of unknown etiology. The DNA of TTV was detected, by semi-nested polymerase chain reaction, in peripheral blood mononuclear cells (PBMC) from the 30 healthy individuals with circulating virus in plasma. A sequence of 222 bases was determined on 6-10 TTV DNA clones each from plasma and 6 clones each from PBMC from eight individuals selected at random from this group, TTV can be classified into genotypes separated by an evolutionary distance > 0.30, which can be divided further into subtypes separated by that of 0.15. Three individuals possessed two different TTV variants of distinct genotypes, with predominant genotypes different between plasma and PBMC. Another possessed TTV of the same genotype in both the plasma and PBMC, but clones with a subtype not seen in plasma were observed in PBMC. A third individual had TTV variants with or without a deletion mutation, and those with the deletion mutation abounded only in PBMC. The remaining three individuals were infected with TTV with the same sequence both in plasma and PBMC. These results indicate that TTV variants with phylogenetic differences could infect the same individual, and that some variants would have a predilection for PBMC. It remains to be seen, however, if TTV replicates in PBMC or whether it has been sequestered before its evolution in the host. J. Med. Virol. 57:252-258, 1999. (C) 1999 Wiley-Liss, Inc.

Recently, a nonenveloped single-stranded DNA virus named TT virus (TTV) has been reported in association with non-A to G post-transfusion as well as sporadic acute and chronic liver disease. A method was developed for the detection of antibody to TTV (anti-TTV) by means of immune precipitation and detection of TTV DNA by the polymerase chain reaction. The test serum was incubated with TTV, recovered from feces of a carrier, and after incubation, the formed immune complexes were precipitated with goat antiserum to human IgG. TTV DNA was sought for by the polymerase chain reaction in both precipitate and supernatant. The detection of TTV DNA in the precipitate, but not in the supernatant, was considered to represent anti-TTV in the test serum. Of the 44 healthy blood donors in Japan, anti-TTV was detected in one of the six (17%) with TTV DNA and 11 of the 38 (29%) without TTV DNA. In the two patients with post-transfusion non-A. to G hepatitis, free anti-TTV developed as they cleared TTV in serum. Anti-TTV complexed with TTV in serum, detectable by precipitating sera with goat anti-human IgG and testing for TTV DNA, elicited while the patients had elevated alanine transaminase levels. The determination of anti-TTV would be useful for detecting resolved infection in surveys for exposure to TTV in the general population, and for establishing the mechanism of liver injury associated with TTV infection. (C) 1999 Published by Elsevier Science B.V. All rights reserved.

Background/Aims: An unenveloped single-stranded DNA virus (TTV) has been reported in association with elevated transaminase levels in patients with posttransfusion hepatitis and in those with acute or chronic liver disease of unknown etiology. To further evaluate the association of TTV with liver disease, TTV DNA was searched for in patients with acute or chronic liver disease of various etiologies. Methods: TTV DIVA was determined by polymerase chain reaction with hemi-nested primers in 64 patients with acute or chronic liver disease of unknown etiology and in 100 with acute or chronic liver disease positive for antibody to hepatitis C virus (HCV) as well as HCV RNA. Results: TTV DNA was detected in two of the seven (29%) patients with acute hepatitis of unknown etiology, but in none of the four patients with acute HCV-associated hepatitis. It was detected in 27 of the 57 (47%) patients with chronic liver disease of unknown etiology at a frequency significantly higher (p<0.001) than that in 17 of the 96 (18%) patients with chronic HCV-associated liver disease. By contrast, RNA of hepatitis G virus was detected in none of the patients with acute hepatitis, and only in one of the 57 (2%) patients with chronic liver disease of unknown etiology as well as in six of the 96 (6%) patients with chronic HCV-associated liver disease. Conclusions: Based on the obtained results, TTV has a role in the development of acute and chronic liver disease of unknown etiology.

This study identifies the prevalence, risk factors for GB virus C (GBV-C) and its relationship with other hepatitis viruses in a general population of Jakarta, Indonesia. A population-based sample of 995 people aged 15 and above was surveyed. Risk factors were identified by questionnaires and home visits. Serum was analyzed for seromarkers of hepatitis viruses, aspartate aminotransferase (AST), and alanine aminotransferase (ALT). The seroprevalence of GBV-C RNA (GB virus C ribonucleic acid) was 2.0%, HBsAg (hepatitis B surface antigen) was 4.1%, anti-HBs (antibody to hepatitis B surface antigen) was 17.4%, anti-HCV (antibody to hepatitis C) was 3.5% and anti-HAV (antibody to hepatitis A virus) was 87.3%. Co-infection between HCV and GBV-C was not found while co-infection between HBV and GBV-C was detected in one case. Compared to low socioeconomic status, middle socioeconomic status had almost a five times higher risk of having GBV-C RNA (adjusted OR = 5.29, 95% CI: 1.56-17.99). Transfusion and total alcohol consumption during lifetime were risk factors for GBV-C RNA (adjusted OR = 4.76, 95% CI: 1.46-15.46 and adjusted OR = 6.24, 95% CI: 1.28-30.35, respectively). In conclusion, the prevalence of GB virus C infections in Jakarta is moderate. Co-infection of GBV-C with HCV is not found, and that with HBV is very low. GBV-C transmission is associated with socioeconomic status, history of transfusion and alcohol consumption. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.

An unenveloped single-stranded DNA virus (TTV) has been reported in association with posttransfusion and acute and chronic hepatitis of unknown etiology. DNA of TTV was tested for by polymerase chain reaction with heminested primers in 127 patients with chronic liver disease and 105 healthy blood donors in Thailand. TN DNA was detected in 23 (59%) of the 39 patients without hepatitis B surface antigen or RNA of hepatitis C virus, at a frequency significantly higher than the detection in 21 (36%) of the 59 patients with HBsAg (P < 0.05) or in 38 (36%) of the 105 blood donors (P < 0.05). Among patients with chronic liver disease, TN DNA occurred in those with liver cirrhosis and hepatocellular carcinoma more frequently than in those with chronic hepatitis (35 of 65 or 54% vs. 20 of 62 or 32%, P < 0.05). There were no differences in age, sex, or markers of infection with hepatitis B, C and GBV-C/HGV viruses, indicating a mode of transmission of TTV different from those of the other hepatitis viruses. Phylogenetic analysis indicated three different genotypes of TTV with six distinct subtypes in Thailand. Based on these results, TTV would have a role in the development of chronic liver disease of unknown etiology in Thailand. J. Mad. Virol 56:234-238, 1998. (C) 1998 Wiley-Liss, Inc.

Five patients with type B or C hepatocellular carcinoma were found to be infected with a nonenveloped DNA virus (TTV) associated with posttransfusion hepatitis of non-A-G etiology. Paired feces and serum samples from these patients were tested for TTV DNA by polymerase chain reaction with seminested primers and their sequences were compared. TTV DNA was detected in sera from all of the patients, while it was detected in feces from th ree patients, including two with high viral titers in serum. When feces and serum from one patient were subjected to floatation ultracentrifugation in CsCl, TTV in feces banded at a peak density of 1.35 g/cm(3) and that in serum at 1.31-1.32 g/cm(3). TTV isolates in three pairs of feces and serum had the identical sequence of 222 base pairs. The excretion of TTV into feces indicates that TTV would be transmitted not only parenterally but also nonparenterally by a fecal-oral route. J. Med. Virol. 56:128-732, 1998. (C) 1998 Wiley-Liss, Inc.

Japanese haemophiliacs have been at high risk for infection with parenterally-transmissible viruses through the use of blood products, especially imported ones, Recently, novel transfusion-transmissible virus, GB virus C (GBV-C)/hepatitis G virus (HGV) were isolated, We investigated the origin and route of transmission of GBV-C/HGV isolates in haemophiliacs in Japan. GBV-C/HGV RNA was measured by nested reverse transcription polymerase chain reaction in 91 Japanese haemophiliacs. Phylogenetic analysis and genotypic grouping of GBV-C/HGV isolates in Japanese haemophiliacs were performed based on sequences in the 5' untranslated region, and the characteristics were compared with those of reported isolates. GBV-C/HGV infection was present in 19 of 91 haemophiliacs (20.9%). Sequence analysis showed that lj of the 19 isolates (78.9%) showed sequence similarity to a group in which mainly West African isolates have been reported, The other 4 isolates (21.1%) showed sequence similarity to Asian isolates. None of the GBV-C/HGV isolates showed sequences similar to those generally found in isolates from USA and Europe. The majority of GBV-C/HGV isolate's found in Japanese haemophiliacs who are considered to have been infected by imported blood products were similar to those detected in West Africa.

One hundred and twenty Sumo wrestlers in Japan received 20 mu g of a hepatitis B vaccine containing 20% (w/w) preS2-region product, while the other 181 received 10 mu g of the vaccine without preS2-region product, four times during 20 months. They were followed for antibody to hepatitis B surface antigen (anti-HBs) by passive hemagglutination up to 32 months after the first vaccination. The seroconversion to anti-HBs occurred more frequently in the wrestlers receiving preS2-plus vaccine than in those receiving preS2-minus vaccine at the end of observation (87% vs. 66%, P < 0.001). Among the seroconverters, anti-HBs titers were higher ill the wrestlers with FreS2-plus than preS2-minus vaccines (geometric mean hemagglutination titer (2(N)): 4.0 +/- 1.8 vs. 3.1 +/- 1.6, P < 0.001). In 27, 83 and ten wrestlers of light (less than or equal to 100 kg), middle (101-150 kg) and heavy(> 150 kg) weight who received preS2-plus vaccine, the seroconversion occurred in 96%,, 86% and 70%, respectively. In 43, 123 and 15 wrestlers of light, middle and heavy weight receiving preS2-minus vaccine, by contrast, seroconversion occurred in 81%, 60% and 67%, respectively. These results indicate that seroconversion to anti-HBs in Sumo wrestlers would be more efficient with preS2-plus than preS2-minus vaccines, and that the efficacy would be inversely correlated with the body weight. It remains to be seen whether an enhanced efficacy of the preS2-plus vaccine was due to the inclusion of preS2-region product or to the amount of S-gene product that was 1.6 times greater than in the preS2-minus vaccine. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.

We have proposed that hepatitis C virus should be classified into eleven genetic groups (types) which further divide into more than 80 genotypes (subtypes). However, only eight genetic groups (1-6, 10 and 1 1) have been defined on the basis of the full-length sequence, Hence, the entire nucleotide sequences of three HCV isolates in genetic groups 7-9 have now been determined. Phylogenetic analysis :over the full-length sequences of these three isolates, along with 30 more in the other eight genetic groups, indicated that genetic groups 6-9 and 11 have bifurcated from a common branch and groups 3 and 10 from another. In the former branch groups 7 and 11, and groups 8 and 9, are closely related. Consequently, HCV can be classified into either eleven (1-1 1) or six groups (1; 2; 3 and 10; 4; 5; 6-9 and 11), allowing a clear separation of group and genotype similarity within the NS5b region or a subregion of 1093 nt, When painwise comparison of 1093 nt in the NSSb sequence was performed on 106 HCV isolates of 36 genotypes in eleven genetic groups, they were classified into either eleven (1-11) or six (1; 2; 3 and 10; 4; 5; 6-9 and Il)genetic groups, However, group and genotype similarities were not clearly separable in either classification, The overlapping range was smaller using the classification into eleven genetic groups as compared to six genetic groups (2 .7 vs 4.7%). These results indicate that HCV might not have evolved in the two-tiered fashion, at least in a strict sense.

Markers of GB virus C (GBV-C) and hepatitis C virus (HCV) were sought in 80 patients before and after they underwent BMT in a metropolitan hospital in Tokyo between 1990 and 1996, RNA of GBV-C was detected in 14 (18%) patients before BMT. Of the 55 patients who had been transfused, 14 (25%) possessed GBV-C RNA at a frequency significantly higher than in the 25 untransfused patients who were all negative (P < 0.01). HCV RNA was detected in three of the 55 (5%) transfused patients, but in none of the 25 untransfused patients. Sera at 3 months after BMT were available for 57 patients. GBV-C RNA persisted in all 10 patients who were infected before BMT, while it was detected in five of the remaining 47 (11%) patients who were not. However, persistent and/or ongoing GBV-C infection had no appreciable influence on patient morbidity or mortality. Two of the 57 patients were positive for HCV RNA before BMT and this persisted after BMT in both. HCV RNA became positive in eight of the remaining 55 (15%) patients who were negative before BMT. Of the 14 patients who received transfusions screened by the first-generation test at BMT, seven (50%) became positive for HCV RNA, a rate significantly higher than the one of 41 (2%) patients who received transfusions screened by the second-generation test (P<0.001). These results indicate that BMT patients are at increased risk of GBV-C infection transmitted by transfusions received before and at the time of BMT, and that the risk of HCV infection has decreased after the implementation of the second-generation anti-HCV test.

An enzyme-linked immunosorbent assay (ELISA) was developed for the determination of hepatitis B virus (HBV) core protein (p21(c)) using monoclonal antibody (mAb) directed to a phosphorylated C-terminal amino acid sequence that is not present in hepatitis B e antigen (HBeAg). HBV virions in the test serum were precipitated with horse polyclonal antibody to hepatitis B surface antigen (HBsAg), dissolved with Tween 20 and NaOH, and then neutralized. HBV core protein (p21(c)), released from HBV cores by this procedure, was sandwiched between immobilized mAb C33 directed to amino acids (aa) 133-140 of the core protein, fixed on a solid support and labeled mAb T2212 that recognizes aa 165-175, only when they are phosphorylated. The method was applied for the detection of phosphorylated p21(c) in sera from symptom-free carriers and patients with chronic hepatitis. The results indicated a higher extent of phosphorylation in p21(c) of HBV cores from symptom-free carriers than hepatitis patients. (C) 1998 Elsevier Science B.V. All rights reserved.

Clinical and molecular biological characteristics were compared between patients who presented with fulminant hepatic failure following acute infection with hepatitis B virus (HBV) and those who developed hepatic failure during they carried HBV. The 11 patients with acute HBV infection had higher levels of alanine aminotransferase (mean +/- SD: 4943 +/- 2867 vs. 1157 +/- 678 IU/L, P < 0.01), more often with a single peak (91% vs. 0%, P < 0.001), and lower total bilirubin levels (15.3 +/- 4.4 vs. 28.1 +/- 14.3 mg/100 mi, P < 0.01) than the 13 patients with chronic HBV infection. Hepatitis B surface antigen was detected less often (55% vs. 100%, P < 0.05) and viral DNA polymerase less frequently (0% vs. 46%, P < 0.05) in the patients with acute than chronic HBV infection. Hepatitis B e antigen was detected in one (9%) patient with acute infection, less frequently than in six (46%) patients with chronic infection (P < 0.05). Mutations in the precore region was detected in HBV DNA clones from ten (91%) patients with acute infection and only in those from eight (62%) patients with chronic infection. All HBV DNA clones from the five (38%) patients with chronic infection that did not have precore mutations, however, possessed mutations in the core promoter. These results indicate that HBV mutants incapable of translating hepatitis B e antigen would play a major role in fulminant hepatic failure occurring after acute HBV infection. In contrast, HBV variants with core promoter mutations for reducing the transcription of hepatitis B e antigen would play an additional role in fulminant hepatic failure developing during chronic infection. (C) 1998 Wiley-Liss, Inc.

RNA of GB virus C (GBV-C) was detected in 12 of the 99 (12%) patients with chronic liver disease in India, including two of 11 (18%) with antibody to hepatitis C virus (HCV), as well as in six of the 21 (29%) patients with anti-HCV in Iran and 16 of the 54 (30%) patients with anti-HCV in Slovenia. Of the 99 patients in India, 47 were without serological markers of hepatitis B or C virus infection and four (9%) of them were positive for GBV-C RNA. Genotypes of GBV-C in the 34 samples from the three countries were invariably G2 that is prevalent in Europe and the United States. In contrast, the distribution of HCV genotypes were much different among them with 2c, 4d and 5a detected locally, in addition to I/la, II/lb and V/3a. These results indicate frequent GBV-C infection with genetic divergence much less than that of HCV in patients with chronic liver disease in India, Iran and Slovenia. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.

Efficacy of 24-week administration of recombinant interferon alfa 2a to 100 patients with chronic hepatitis B was investigated. 9 MU of Interferon was injected daily for 2 weeks followed by 22 week af 9 MU interferon thrice weekly. Among 52 HBeAg-positive patients who completed interferon therapy, e antigen became negative in 27 (52%) and ALT turned normal in 25 (48%) at 24 weeks after discontinuation of interferon. Serum HBVDNA decreased in all cases during therapy, although none of the patients persistently cleared serum HBVDNA. Of 39 HBeAgnegative patients, normalization of ALT was retained in 23 (59%) at 24 week after therapy. In this group, serum HBVDNA became negative during interferon therapy in 9 (23%) cases. Twenty four week administration of interferon seems to be an effective therapeutic approach for chronic hepatitis B, with or without serum HBe-antigen.

The prevalence of hepatitis C virus (HCV) infection and factors relating to the HCV transmission were evaluated in a community without high mortality from chronic liver disease in Niigata prefecture. A total of 2,231 subjects were examined to detect anti-HCV core antibodies by enzyme-linked immunosorbent assay with synthetic peptides CP14 and CP9. The prevalence was 1.66% (95% CI 1.17% to 2.29%) and tended to increase with age. The values were lower than those reported from districts with hepatic disease endemic. Histories of blood transfusion (relative risk (RR) 5.51 95% CI 2.90 to 10.48) and surgery with hospital admission (RR 4.43 95% CI 2.04 to 9.65) were significantly associated with the anti-HCV core antibodies positive. Multiple logistic analysis corroborated independency of these factors. Among 188 subjects who experienced surgery and/or blood transfusion after 1990, only one (0.5%) had HCV infection. By contrast, 8 (3.5%) were positive in subjects who experienced first acupuncture therapy after 1990. The acupuncture therapy in alternative medicine could be still related to the HCV transmission.

Efficacy of standard regimens (e,g., 3-6 MU for 24 weeks) of alfa-IFN therapy for chronic hepatitis C has been limited, particularly in patients with HCV/1b. To see if higher-dose longer term treatment is more effective, we tried a 9 MU 60-week regimen. HCV/1b-infected chronic hepatitis patients received 9 MU IFN alpha 2a everyday but Sunday for 2 weeks and thrice a week for next 10 weeks, and 76 patients became HCV RNA-negative while 81 remained positive. The RNA-negative patients were then randomized to receive 3 MU (group I, n=37) or 9 MU (group II, n=39) for 48 weeks. Of che RNA-positive patients, only those with normal ALT received another 9 MU 48-week treatment (group III, n=45). Sustained responders (SR) were defined as those with negative RNA and normal ALT 6 months after the therapy. SR rates based on intent-to-treat principle did not differ significantly between groups I and II (30% vs 41%), but those based on the protocol-compatible cases showed a significant difference (32% vs 56%, p=0.034). SR rate in group III was significantly lower than those in group II. Adverse effects of IFN, developed more frequently in groups II and III than in group I, were mostly reversible. In conclusion, our results encourage 9 MU 60-week IFN alpha treatment in HCV/1b-infected patients with careful attention to adverse effects, and suggest that the treatment should be discontinued if HCV RNA does not disappear within 12 weeks.

The genomic DNA of a novel virus named TT virus (TTV), associated with posttransfusion hepatitis of unknown etiology, was cloned from plasma of a blood donor with an elevated transaminase level but without serological markers of known hepatitis viruses, and its sequence of 3739 bases was determined. TTV had a density of 1.26 g/cm(3) in sucrose, which did not change after the treatment with Tween 80. The viral genome was sensitive to DNase I and Mung Bean Nuclease. Hence, TTV would be an unenveloped, single-stranded DNA virus. Two possible open reading frames in different frames were identified, capable of encoding 770 and 202 amino acids, respectively. When a partial sequence of 356 bases was compared among TTV isolates from 78 sera from blood donors and hepatitis patients, it showed considerable divergence with differences of up to 30%. Oligonucleotide primers were designed on two well-conserved regions for the detection of TTV DNA in serum and biopsied liver tissues by polymerase chain reaction. TTV DNA was detected in sera from 9 of 19 (47%) patients with fulminant hepatitis and 41 of 90 (46%) patients with chronic liver disease of unknown etiology. TTV DNA was detected in liver tissues of all the five patients tested. in titers equal or 10-100 times higher than those in the corresponding sera. These results indicate that TTV would be responsible for a part of acute and chronic liver disease of unknown etiology. (C) 1998 Elsevier Science Ireland Ltd.