Molecular detection of TT virus and SEN virus infections in hemodialysed patients and blood donors in south of Iran.

Background: SEN virus (SEN-V) and TT virus (TTV) have been classified in the circoviridae family. Both are single-stranded, non-enveloped DNA viruses of about 3800 nucleotides. Patients on maintenance hemodialysis (HD) have a high risk of blood-borne viral infections. SEN-V and TTV has been reported from a number of HD units from various countries throughout the world. Materials and Methods: A total of 377 blood samples obtained from 150 healthy donors and 227 HD patients were collected at the HD center. SEN-V and TTV DNA was determined by polymerase chain reaction (PCR) in all samples. Results: TTV was detected in 109 (48.01%) of 227 hemodialysed patients and 14 (9.33%) of 150 voluntary blood donors (significant, P < 0.05). The PCR results for SEN-V-D/H DNA showed that 65 (28.63%) were positive for SEN-V-D and 33 (14.53%) were positive for SEN-V-H. 9.69% of 227 patients were positive for SEN-V-D/H co-infection. In the control group, SEN-V-D was detected in 14 (9.33%) and SEN-V-H was detected in 15 (10%) of the 150 (100%) blood donors. Conclusion: These findings show that the prevalence of SEN-V-D/H and TTV is higher than healthy blood donors. Also, these results indicate that the prevalence of SEN-V and TTV infections in our region is similar with that in other countries.

TT Virus Detection Using Different PCR Primer Sets in Healthy and Infected Individuals with Hepatitis B or C Viruses / 대한임상미생물학회지

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.

Distribution of TT Virus Genotypes and Genogroups in 69 Healthy and 59 Hepatitis B Virus Infected Korean Individuals / 대한진단검사의학회지

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.

TT Virus (TTV) Infection in General Population, Chronic Liver Diseases, Hemodialysis, and Transfused Patients / 대한임상미생물학회지

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.

Transfusion-transmitted Virus and TTV-like Mini Virus Infection in Blood Products / 대한진단검사의학회지

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.

Clinical Characteristics of Non-B, Non-C Hepatocellular Carcinoma and Detection of HBV, HCV and TTV Viremia / 대한간학회지

BACKGROUND/AIMS: About 15% of Korean hepatocellular carcinoma (HCC) are negative both of Hepatitis B surface antigen (HBsAg) and anti-hepatitis C virus (anti-HCV) in their sera. They can be classified as a non-B, non-C hepatocellular carcinoma group (NBNC group). The aims of our study were, firstly, to describe the clinical characteristics of Korean NBNC HCC and compare them with those of HBsAg-positive HCC (HBV group) and anti-HCV-positive HCC (HCV group). Secondly we wanted to assess the frequency of viremia of HBV, HCV and transfusion-transmitted virus (TTV) in NBNC HCC patients. METHODS: We prospectively collected clinical data and sera from 113 NBNC HCC patients and performed PCR for HBV DNA, HCV RNA and TTV DNA. We also collected clinical data from 125 HBsAg-positive HCC patients and 61 anti-HCV-positive HCC patients during a similar period. RESULTS: The mean age of the NBNC HCC group was 59 years, in-between that of the HBV and the HCV groups. A History of heavy alcohol drinking was found in 48% of the NBNC HCC group. This was significantly higher than that of the HBV group, but similar to that of the HCV group. Serum alphaFP level in the NBNC HCC group was more frequently in the normal range compared to that in the HBV and HCV groups. The detection rates of HBV DNA, HCV RNA and TTV DNA in the NBNC HCC group were 17%, 13%, and 67% respectively. CONCLUSIONS: The NBNC HCC patients seemed to comprise a heterogeneous group of various etiologies and clinical presentations. About one third of these patients displayed evidence of viremia of HBV or HCV.

Tissue tropism of TT virus in experimentally infected Rhesus monkey / 中华传染病杂志

Objective To study tissue tropism of TT virus in experimentally infected Rhesus monkey. Methods Various tissues were collected from 5 experimentally infected monkeys during the viremic period. Total DNA was extracted from tissues of 5 experimentally infected Rhesus monkeys. A dot hybridization was done with virus double DNA strand probe or single antisense strand probe. Results The double strand probe was hybridized with DNA of liver, bone marrow, spleen, stomach, small intestine and colon. The single strand antisense probe was hybridized only with DNA of liver, small intestine and bone marrow of all 5 monkeys, but not with that of other tissues.Conclusions As the viral genome is of negative polarity, the plus stranded fragment identified in our study might be a replicative intermediate, and is only demonstrated in liver, small intestine, and bone marrow by dot blot hybridization with single stranded antisense probe. It suggests that TT virus might be, tropism of liver, small intestine, and bone marrow, and replicate in tissue mentioned.

Prevalence of TT virus (TTV) infection in patients with liver diseases in Korea / 대한내과학회지

BACKGROUND: TT virus (TTV), an unenveloped single-stranded DNA virus, has been reported in patients with non A-G posttransfusion hepatitis in Japan. Since it has been distributed globally afterward, it was suggested to be a possible causative agent in a proportion of cases with cryptogenic acute and chronic hepatitis. Therefore, we investigated the prevalence and clinical significance of TTV infection in Korean patients with acute and chronic liver diseases. METHODS: TTV DNA was determined by polymerase chain reaction with semi-nested primers in sera of 94 patients with liver diseases: 38 with non-ABC liver diseases, 33 with HBV infection and 23 with HCV infection. RESULTS: TTV DNA was detected in 7.9% of non-ABC group, 6.1% of HBV group and 13.0% of HCV group. The positive rates of TTV DNA among three groups were not different statistically. The prevalences of TTV in acute and chronic liver disease were not different. For our study, six out of eight patients with positive TTV DNA had a past history of transfusion. CONCLUSION: Although TTV infection exists in Korea, it seems unlikely that the virus is responsible for liver diseases of unknown etiology.

STUDY OF TT VIRUS IN EXPERIMENTALLY INFECTED RHESUS MONKEY / 解放军医学杂志

To study tissue distribution of TTV in experimentally infected Rhesus monkey and if the TT virus is hepatotropic. Total DNA was extracted from tissues of 5 experimentally infected Rhesus monkeys. TTV was detected by PCR,and dot hybridization was done with virus double DNA strand probe or single antisense strand probe. The double strand probe was hybridized with DNA of liver, bone marrow, and spleen, stomach, small intestine, colon. and sera. In the above tissues , the virus was also positive as shown by PCR. The single strand antisense probe was only hybridized with DNA of liver, bone marrow,and small intestine of all 5 monkeys, but not with that of other tissues. It suggested that TTV could infect many tissues of Rhesus monkey. Only the liver ,bone marrow, and small intestine presented the virus positive single strand, which might be a replicative intermediate of the virus. It suggests that TT virus replicates in liver , bone marrow, and small intestine,and it might be hepatotropic.