Infection by an unenveloped DNA virus associated with non‐A to ‐G hepatitis in Japanese blood donors with or without elevated ALT levels

Itoh, Keiichi; Hirakawa, K.; Okamoto, Hiroaki; Ukita, Masato; Tanaka, Hiromu; Sawada, Natsumi; Tsuda, Fumio; Miyakawa, Yuzo; Matsui, Makoto

doi:10.1046/j.1537-2995.1999.39050522.x

Cited by 26 publications

(15 citation statements)

References 23 publications

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“…This may explain why, in several studies conducted with detection methods of limited sensitivity, TTV infection was found more frequently in patients with non-A±E hepatitis than in other individuals [Ikeda et al, 1999;Itoh et al, 1999;Orii et al, 1999]. Because these patients were not at increased risk for parenterally transmitted virus infection, the ®nding might also imply that a sustained TTV replication might be responsible for at least some liver damage and account for a proportion of unexplained chronic hepatitis.…”

Section: Discussionmentioning

confidence: 99%

TT virus levels in the plasma of infected individuals with different hepatic and extrahepatic pathology

et al. 2001

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TT virus (TTV) infection is extremely widespread in the general population. A sensitive real-time PCR assay was developed that quantitated accurately the most prevalent TTV genotypes in Italy. When used to test 217 individuals for TTV viraemia, the overall prevalence was 94%. Viraemia levels varied widely amongst individual subjects, with no major differences related to gender or age. The highest TTV titres were in haemophiliacs and in patients with non-A-E hepatitis, but they did not differ from the group with miscellaneous diseases. HIV- and HCV-infected subjects and patients with primary liver diseases had TTV loads similar to those of healthy individuals.

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Section: Discussionmentioning

confidence: 99%

TT virus levels in the plasma of infected individuals with different hepatic and extrahepatic pathology

et al. 2001

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“…However, TTV DNA detectable by N22 PCR was significantly more frequent in the donors with elevated ALT levels than in those with normal levels (22.1 vs. 15.7%, p ! 0.02) [24].…”

Section: Ttv Infection and Liver Injurymentioning

confidence: 99%

“…Primers deduced from noncoding region can detect TTV DNA, irrespective of different genotypes, with a frequency of 190% in the healthy general population in Japan [20]. By contrast, primers deduced from the N22 region in the coding region detect TTV DNA of restricted genotypes, such as genotypes 1 and 2 [5,23], with a prevalence of 10-20% in Japan [5,24] and of only 1-2% in the United States and England [6,7]. Table 2 compares TTV DNA titers of five sera (No.…”

Section: Genomic Heterogeneity Of Ttvmentioning

confidence: 99%

A Novel Unenveloped DNA Virus (TT Virus) Associated with Acute and Chronic Non-A to G Hepatitis

Okamoto¹,

Nishizawa²,

Ukita³

1999

Intervirology

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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 ∼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.

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“…Undoubtedly, the above observations rule out the notion that clinically evident liver disease is a frequent consequence of TTV infection. However, the evidence is not totally unequivocal, since data also exist that are compatible with the possibility that, in some cases, transient and mild abnormalities in liver enzyme levels are associated with TTV infection (33,34,56,61,65,68,81,88,110,126). Likewise, in several series of HCV patients, coinfection with TTV appeared to be associated with increased severity of biochemical and histological parameters of liver damage (15,22,48,56,172,175,191).…”

Section: Clinical Significancementioning

confidence: 99%

Molecular Properties, Biology, and Clinical Implications of TT Virus, a Recently Identified Widespread Infectious Agent of Humans

et al. 2001

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TT virus (TTV) was first described in 1997 by representational difference analysis of sera from non-A to non-G posttransfusion hepatitis patients and hence intensively investigated as a possible addition to the list of hepatitis-inducing viruses. The TTV genome is a covalently closed single-stranded DNA of approximately 3.8 kb with a number of characteristics typical of animal circoviruses, especially the chicken anemia virus. TTV is genetically highly heterogeneous, which has led investigators to group isolates into numerous genotypes and subtypes and has limited the sensitivity of many PCR assays used for virus detection. The most remarkable feature of TTV is the extraordinarily high prevalence of chronic viremia in apparently healthy people, up to nearly 100% in some countries. The original hypothesis that it might be an important cause of cryptogenic hepatitis has not been borne out, although the possibility that it may produce liver damage under specific circumstances has not been excluded. The virus has not yet been etiologically linked to any other human disease. Thus, TTV should be considered an orphan virus

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Infection by an unenveloped DNA virus associated with non‐A to ‐G hepatitis in Japanese blood donors with or without elevated ALT levels

Abstract: 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.

Cited by 26 publications

References 23 publications

TT virus levels in the plasma of infected individuals with different hepatic and extrahepatic pathology

TT virus levels in the plasma of infected individuals with different hepatic and extrahepatic pathology

A Novel Unenveloped DNA Virus (TT Virus) Associated with Acute and Chronic Non-A to G Hepatitis

Molecular Properties, Biology, and Clinical Implications of TT Virus, a Recently Identified Widespread Infectious Agent of Humans

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