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

BACKGROUND: We analyzed the results of external proficiency tests for HBsAg, anti-HCV and anti-HIV, and these tests are currently used for blood donor screening in Korea. METHODS: The external proficiency testing (EPT) data was retrospectively collected from 2001 to 2009 from the Korean Association of Quality Assurance for Clinical Laboratories, and this association includes those institutes that have blood centers. The pooled patient sera or converted sera from the plasma were used for EPT. The year 2004 data includes the Recombinant HBsAg variant (Gly/Arg 145). RESULTS: A total 806 institutes participated in this evaluation. The average discordant rate for HBsAg, anti-HCV and anti-HIV in the blood centers was 0.2%, 0.6% and 1.0%, respectively for the years 2001~2009. For the HBsAg test, the discordant rate was less than 0.5% in 2009, yet there was a much higher rate (1.6~22.2%) in 2004 when using the recombinant HBsAg variant. CONCLUSION: HBV variants or low positive antigen or antibody titers were problematic in the current clinical laboratory, and so a systematic quality assurance program should be conducted with using control materials.
Academies and Institutes ; Blood Donors ; Donor Selection ; Genotype ; Hepatitis B Surface Antigens ; Humans ; Korea ; Mass Screening ; Plasma ; Retrospective Studies ; Tissue Donors ; Torque teno virus ; Viruses

BACKGROUND: TT virus (TTV) infection is highly prevalent in general population and patients with hepatitis B virus (HBV) infection. The aim of the present study was to determine the distribution of the genotypes and genogroups of TTV in healthy and HBV-infected individuals in Korea. METHODS: Distribution of TTV genotypes and genogroups was investigated in the serum samples of 69 healthy and 59 HBV-infected individuals. PCR products of N22 region were genotyped by sequence analysis. TTV genogroups were determined by 5 different genogroup-specific PCR assays. RESULTS: Among the 20 sequenced isolates, 9 (45%) were genotype 2, 8 (40%) were genotype 1, 2 (10%) were genotype 3, and 1 (5%) was genotype 4. TTV genogroup 4 was found most frequently (52/128), followed by genogroup 3 (42/128), genogroup 1 (35/128), genogroup 5 (32/128), and genogroup 2 (1/128). Mixed infections with different genogroups were frequent. CONCLUSIONS: TTV genotype 2 and 1 are predominant genotypes. TTV genotype 3 was detected for the first time in Korea. TTV genogroups 4 and 3 were predominant genogroups. No significant difference was observed in the distribution of TTV genogroups between healthy and HBV-infected individuals.
Adult ; Amino Acid Sequence ; DNA Virus Infections/diagnosis/*virology ; Female ; Genotype ; Hepatitis B/*complications/diagnosis ; Humans ; Korea ; Male ; Middle Aged ; Molecular Sequence Data ; Phylogeny ; Polymerase Chain Reaction/methods ; Torque teno virus/classification/*genetics

BACKGROUND: TT virus (TTV) infection is highly prevalent in the general population and in the patients infected with hepatitis B virus (HBV) or hepatitis C vius (HCV). The aim of the present study was to assess the positive rates of TTV DNA using different PCR primer sets in healthy and HBV or HCV-infected individuals in Korea. METHODS: TTV DNA was investigated in serum samples of 69 healthy individuals and 59 HBV-infected and 34 HCV-infected individuals by nested PCR assays using primers from N22 region, 5'-untranslated region (UTR), and 3' UTR of viral genome. RESULTS: TTV DNA was detected in 43% of total study populations using N22 primers, in 69% using 5' UTR primers and, in 64% using 3' UTR primers. No significant difference was observed in the positive rates of TTV DNA between healthy and HBV or HCV- infected individuals. CONCLUSION: The PCR assays for TTV DNA using 5' UTR primers and 3' UTR primers exhibited higher positive rates than that of the assay using N22 primers without any significant difference between healthy and HBV or HCV-infected individuals.
3' Untranslated Regions ; 5' Untranslated Regions ; DNA ; Genome, Viral ; Hepatitis B virus ; Hepatitis B* ; Hepatitis C ; Hepatitis* ; Humans ; Korea ; Polymerase Chain Reaction* ; Torque teno virus*

BACKGROUND: TT virus (TTV), isolated initially from a Japanese patient with posttransfusion hepatitis of unknown etiology, was suggested to be a new causative agent of hepatitis. However, it has been found to infect both healthy and diseased individuals and numerous studies have raised questions about its pathogenic role in hepatitis. In order to study its prevalence and clinical impact on hepatitis, we assessed the frequency of TTV DNA. METHODS: Serum samples were obtained from 60 cases of the controls, 77 cases of chronic liver diseases, 44 cases of hemodialyzed patients, and 65 cases of transfused patients. TTV DNA was detected using nested polymerase chain reaction and alanine aminotransferase (ALT), aspartate aminotransferase (AST), and hepatitis B surface antigen (HBsAg) were measured. RESULTS: TTV DNA was detected in 41.7% of the controls, 51.9% of patients with chronic liver diseases, 68.2% of hemodialyzed patients and 61.5% of transfused patients. Comparison between patients with or without TTV revealed no significant differences in AST, ALT, and HBsAg test results. CONCLUSION: The prevalance of TTV infection in patients with chronic liver diseases was similar to that in the controls. TTV infection was not related to abnormal liver function findings and HBsAg positivity. We found no relationship between TTV infection and chronic liver diseases.
Alanine Transaminase ; Asian Continental Ancestry Group ; Aspartate Aminotransferases ; DNA ; Hepatitis ; Hepatitis B Surface Antigens ; Humans ; Liver Diseases* ; Liver* ; Polymerase Chain Reaction ; Prevalence ; Renal Dialysis* ; Torque teno virus*

Infectious agents, including viruses, bacteria and parasites, can be transmitted via human blood and blood products. Of greatest importance are viruses such as human immunodeficiency virus types 1 and 2 (HIV-1/2), hepatitis B virus (HBV), and hepatitis C virus (HCV), followed by other viruses such as cytomegalovirus (CMV) and human parvovirus B19. Viruses such as hepatitis G virus and TT virus can also be transmitted via blood products, but their pathogenicity is still unclear. Bacteria, including Treponema pallidum and Yersinia enterocolitica and parasites such as Plasmodium species can also be transmitted from donors to recipients. Furthermore, the threat of newly emerging pathogens that can affect the blood safety, such as the variant Creutzfeld-Jakob Disease, is always present. The measures to reduce the risks of transfusiontransmitted infection within the last 20 years, such as donor selection and testing donated blood for various infectious agents, have had a remarkable impact on the safety of blood supply. Nevertheless, the public expectation of absolute blood safety continues to exert pressure to eliminate the remaining risks. The recent introduction of molecular biology techniques combined with viral inactivation methods is directed to get this goal.
Bacteria ; Blood Safety ; Cytomegalovirus ; Donor Selection ; GB virus C ; Hepacivirus ; Hepatitis B virus ; HIV ; Humans ; Molecular Biology ; Parasites ; Parvovirus B19, Human ; Plasmodium ; Tissue Donors ; Torque teno virus ; Treponema pallidum ; Virulence ; Virus Inactivation ; Yersinia enterocolitica

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*

PURPOSE: Transfusion transmitted virus (TTV) is a newly discovered virus and to date the contribution of TTV to liver disease remains unclear. Little is known about the frequency of TTV infection in children in Korea. The purpose of this study was to investigate the prevalence and genotypic distribution of TTV carried by healthy children and patients with hepatitis in Korea. METHODS: Eighty eight of healthy children and three groups of patients with hepatitis-14 patients with chronic hepatitis B, 12 patients with chronic hepatitis C and 25 patients with hepatitis of unknown etiology-were tested. TTV DNA was detected by semi-nested PCR using primer sets generated from N-22 region and from 5' noncoding region (NCR) of the viral genome. PCR products derived from 8 patients with hepatitis and from 11 healthy children were sequenced and a phylogenetic tree was constructed. RESULTS: TTV was found by PCR with N22 primer in 11.3% of healthy children, 28.5% of children with hepatitis B, 25% of children with hepatitis C, 24% of children with hepatitis of unknown etiology. TTV DNA was found by PCR with 5'NCR primer in 32.9% of healthy children, 71.4% of patients with chronic hepatitis B, in 50% of patients with hepatitis C and in 48% of patients with hepatitis of unknown etiology. TLMV DNA was found in 48.9% of healthy children, 21.4% of patients with hepatitis B, 16.6% of patients with hepatitis C, 40% of patients with hepatitis of unknown etiology. Among the sequenced isolates, 10(52%) belonged to genotype 1 (G1) and others belonged to genotype 2 (G2) or genotype 3 (G3). Among the G1 sequences, 7 were grouped as G1a. CONCLUSION: TTV infection was common in healthy children and in patients with hepatitis. But, the prevalence of TTV DNA by 5'NCR primer was relatively high in patients with hepatitis B and there may be some association between TTV and hepatitis B virus infection. G1 was the major genotype of the studied population.
Child* ; DNA ; Genome, Viral ; Genotype* ; Hepatitis B ; Hepatitis B virus ; Hepatitis B, Chronic ; Hepatitis C ; Hepatitis C, Chronic ; Hepatitis* ; Humans ; Korea ; Liver Diseases ; Polymerase Chain Reaction ; Prevalence* ; Torque teno virus*

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*

Adult ; China ; epidemiology ; Circoviridae Infections ; epidemiology ; virology ; DNA, Viral ; analysis ; Female ; Genotype ; Hepatitis, Viral, Human ; virology ; Humans ; Male ; Substance Abuse, Intravenous ; virology ; Torque teno virus ; genetics ; isolation & purification