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Torque teno virus*

This study assessed the prevalence of TT virus and GBV-C/HGV in some groups: non A-E hepatitis patients, blood donors and HCV infection group. HGV RNA was detected by RT-nested PCR and TTV DNA was determined by semi-nested PCR. The result showed that 4% TTV DNA positive was found in 75 non A-non E hepatitis patients. The positive rates of TTV DNA were increased among blood donors and HCV infection group. All of non A – non E hepatitis patients and bolld donors were HGV RNA negative but the rate of GBV-C/HGV RNA positive was very high in HCV infection group. The itiopathogenetic role of TTV and GBV-C/HGV in chronic hepatitis of non A-non E wasf still undefined
Hepatitis ; Torque teno virus

DNA, Viral ; chemistry ; Humans ; Polymerase Chain Reaction ; Sequence Analysis, DNA ; Torque teno virus ; classification ; genetics

BACKGROUND: The TT virus (TTV) is a recently discovered, single-stranded circular DNA virus in the serum of the patients with post-transfusion hepatitis and it is thought to be one of the causative agents of cryptogenic hepatitis. In this study, we evaluated the prevalence and clinical significance of TTV viremia in general populations and patients on hemodialysis. METHODS: Sera of 115 general populations and 69 patients on hemodialysis were examined for TTV viremia by semi-nested polymerase chain reaction using primers deduced from the N22 region. RESULTS: The TTV was detected in 26.1% (18 of 69) of the patients on hemodialysis and was not different from the 20.9% (24 of 115) prevalence in general populations. Two patients on hemodialysis that revealed biochemical evidence of acute hepatitis were the sole TTV infection without other hepatitis virus infection but the mean alanine aminotransferase level was not significantly different according to the TTV viremia. The TTV was persistently detected in the sera of eight of thirteen patients (61.5%) 12 month later without any evidence of hepatitis. CONCLUSIONS: TTV is widespread in general populations and shows similar prevalence in patients on hemodialysis. Viral persistence and nonparenteral transmission may be possible. The relationship between the TTV viremia and hepatitis was not proved.
Alanine Transaminase ; DNA, Circular ; Hepatitis ; Hepatitis Viruses ; Humans ; Polymerase Chain Reaction ; Prevalence* ; Renal Dialysis* ; Torque teno virus* ; Viremia*

PURPOSE: Transfusion-transmitted virus(TTV) is an newly described nonenveloped human virus, with a circular, negative stranded DNA genome. Although a high prevalence of TTV infection in the normal population has been demonstrated, there is a still possibility of association with hepatitis according to the genotype of TTV. The aim of this study is to investigate the prevalence of TTV infection in Korean children. METHODS: Nested polymerase chain reaction(PCR) using priner sets generated from the noncoding region(NCR) of the viral genome was done in 105 children without liver disease, aged 0-15 years. We performed a second set of PCR using N22 primer in 88 children after the first set of PCR. RESULTS: The TTV DNA was detectable in 36(34%) of 105 children without hepatitis by 5'NCR primer. The prevalence of TTV varied with age:<1 y,16%(4/25); 1-3 y, 44%(15/31); 4-6 y, 31%(5/ 16); 7-9 y, 25%(3/12); 10-15 y, 14%(3/21). By using N22 primers, the prevalence of TTV DNA in children without hepatitis was 11.3%(11/88):<1 y 8%(2/25); 1-3 y, 13.7%(4/29); 4-6 y, 6.2%(1/16); 7-9 y, 33.3%(2/6); 10-14 y, 8.2%(1/12). CONCLUSION: Our result showed a high prevalence of TTV infection, varying with age, in Korean children. Further evaluation of genotypes of TTV in patients with hepatitis and normal children is needed.
Child* ; DNA ; Genome ; Genome, Viral ; Genotype ; Hepatitis ; Humans ; Liver Diseases ; Polymerase Chain Reaction ; Prevalence* ; Torque teno virus*

BACKGROUND: Transfusion-transmitted virus (TTV) and TTV-like mini virus (TLMV) are small DNA virus with single-stranded, closed circular, antisense genome infecting man. TTV and TLMV are trans-missible by transfusion. However there had been a few study about TTV prevalence and no study about prevalence in blood donors in Korea. There has been no study about the TTV and TLMV infection in blood products in Korea. The aim of this study was to gain the prevalence of two viruses in blood products. METHODS: A total of 150 plasma samples from blood products (each 50 units of Red blood cell, whole blood, and platelet concentrate) were tested. The samples are obtained from the segments of the blood products. TTV DNA was detected using polymerase chain reaction (PCR) with two sets of primers (A set and B set) and TLMV DNA was detected using nested PCR with primer set C. RESULTS: TTV DNA was detected in 85.3% (128/150) of blood products. TLMV DNA was detected in 41.3% (62/150) of blood products. Either TTV or TLMV was detected in a total of 140 blood products (92.3%) and both TTV and TLMV were detected in 50 products (33.3%). CONCLUSIONS: The blood products are frequently infected with TTV and (or) TLMV in Korea and they can be transmissible by blood products with high probability.
Blood Donors ; Blood Platelets ; DNA ; DNA Viruses ; Erythrocytes ; Genome ; Humans ; Korea ; Plasma ; Polymerase Chain Reaction ; Prevalence ; Torque teno virus*

BACKGROUND: Transfusion-transmitted virus (TTV) is a small DNA virus with single-stranded, closed circular, antisense genome infecting humans. The TTV has been classified into five major genomic groups 1-5. There have been a few studies on TTV prevalence in blood donors and blood products in Korea. However there have been no reports on the TTV genomic groups in Korea. The aim of this study was to gain information on TTV genomic groups in blood products in Korea. METHODS: A total of 50 plasma samples from blood products (25 units each of red blood cell and whole blood) were tested. The samples are obtained from the segments of the blood products. TTV DNA was detected using polymerase chain reaction (PCR) with two sets of universal primers (A set and B set), and TTV genomic groups were determined using PCR with group specific primer sets. RESULTS: TTV DNA was detected in 96% (48/50) of the blood products: the TTV genomic group 3 was found the most frequently (52%, 26/50), followed by group 4 (46%, 23/50), group 1 (20%, 10/50), group 5 (10%, 5/20), and group 2 (2%, 1/50). There were seven blood products (14%) infected with TTVs but their genomic groups were not identified with group specific primer sets. Among the blood products, 44% (22/50) were infected with a unique TTV genomic group; 38% (19/50) were coinfected with TTV from 2 (28%, 14/50) or 3 (10%, 5/50) genomic groups. CONCLUSIONS: Blood products are frequently infected with TTV and all five known genomic groups are detected in Korea.
Blood Donors ; DNA ; DNA Viruses ; Erythrocytes ; Genome ; Humans ; Korea ; Plasma ; Polymerase Chain Reaction ; Prevalence ; Torque teno virus*

OBJECTIVETo establish a simple, sensitive, specific and less-costly method for detecting genotypes of TT virus (TTV).

METHODSTTV DNA was tested by nested polymerase chain reaction (nPCR) in sera from 180 patients with different types of viral hepatitis and 96 normal individuals in Beijing. TTV genotypes were determined in 40 sera collected from TTV DNA positive patients by heteroduplex mobility assay (HMA) and through sequencing.

RESULTSThe positive rates of TTV DNA in viral hepatitis patients and normal individuals were 22.2% (40/180) and 19.8% (19/96), respectively (chi(2) = 0.220, P = 0.639). TTV DNA positive rates of patients with hepatitis A, B, C, E and non-A to E were 20.0% (6/30), 16.7% (5/30), 23.3% (7/30), 36.7% (11/30) and 18.3% (11/60), respectively. Of 40 TTV DNA positive patients, 20 (50.0%) were TTV G1, 7 (17.5%) TTV G2, 10 (25.0%) coinfected with different genotypes of TTV, and 3 untyped by HMA. Twenty G1 and 7 G2 detected by HMA were confirmed by sequence analysis. Of 10 patients coinfected with different genotypes of TTV, 5 were G1 and G2, 2 G1 and G3, 1 G1 and G4, 1 G1 and G3, and 1 with G1, G2 and G3 coinfections.

CONCLUSIONHMA was recognized as simple, sensitive, specific and less-costly, thus could be used for genotyping of TTV.

DNA, Viral ; analysis ; Genotype ; Hepatitis, Viral, Human ; virology ; Heteroduplex Analysis ; methods ; Humans ; Phylogeny ; Torque teno virus ; classification ; genetics

BACKGROUND: Although a marked proportion of thalassemic patients acquire Torque teno virus (TTV) through blood transfusion, its clinical importance is unclear. This study was designed to investigate the clinical importance of TTV infection in thalassemic patients with and without hepatitis C virus (HCV) co-infection in Iran. METHODS: In this case-control study, 107 thalassemic patients on chronic transfusion and 107 healthy individuals were selected. According to HCV and TTV infection status (detected by semi-nested PCR), patients were categorized into 4 groups: TTV and HCV negative, TTV positive, HCV positive, and TTV and HCV positive. Blood ferritin, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels in these 4 groups were assessed. RESULTS: Approximately half of the thalassemic patients (50.5%) and 27.1% of controls had TTV infection. Thalassemic patients had a greater chance of TTV infection compared to the control group with a sex-adjusted OR of 4.13 (95% CI=2.28-8.13). The increased levels of ALT, AST, and ferritin in the TTV and HCV-infected group were not significantly different from those in the TTV and HCV negative group. Co-infection with TTV and HCV did not significantly increase ALT, AST, and ferritin levels compared to infection with TTV alone. CONCLUSION: Although common in thalassemic patients, TTV infection appears to have a negligible role in increasing the severity of liver disease, even when co-infection with HCV occurs.
Alanine Transaminase ; Aspartate Aminotransferases ; Blood Transfusion ; Case-Control Studies ; Coinfection ; Ferritins ; Hepacivirus ; Hepatitis ; Hepatitis C ; Humans ; Liver Diseases ; Thalassemia ; Torque ; Torque teno virus

OBJECTIVETo determine whether the transfusion-transmitted virus (TTV) is hepatotropic.

METHODSTotal DNA was extracted from various tissues of 5 experimentally infected Rhesus monkeys during the viremic period. A dot hybridization was done with viral double stranded DNA probes or single antisense probes.

RESULTSThe double-stranded probe was hybridized with DNA from the liver, bone marrow, spleen,stomach, small intestine and colon. The single-stranded antisense probe was hybridized with DNA from the liver, small intestine and bone marrow of all 5 monkeys, but not with that from other tissues.

CONCLUSIONSAs the viral genome was of negative polarity, the plus-stranded fragment identified in our study might be a replicative intermediate, and was only demonstrated in the liver, small intestine, and bone marrow by dot blot hybridization with single-stranded antisense probes. It is suggested that the TTV replicates in the liver, bone marrow and small intestine, and TTV might be hepatotropic.

Animals ; Bone Marrow ; virology ; DNA Virus Infections ; virology ; DNA, Viral ; analysis ; Intestine, Small ; virology ; Liver ; virology ; Macaca mulatta ; Torque teno virus ; genetics ; isolation & purification ; physiology ; Virus Replication