Prevalence Of TT Virus Infection Research Articles

Study of the Associations Between TT Virus Single and Mixed Infections With Leukemia.

Background:The pathogenic association of Transfusion Transmitted Virus or Torque teno Virus (TT Virus) single and mixed infections with leukemia was under evaluation in these years but confront with controversies. This hypothesis is based on the higher prevalence of TT Virus infection in patients with leukemia compared with controls.Objectives:The aim of this study was to determine the frequency of TT Virus, Cytomegalovirus (CMV), Hepatitis B Virus (HBV), and Hepatitis C Virus (HCV) infections in patients with leukemia and healthy controls.Patients and Methods:In this cross sectional study, 95 patients with leukemia and 100 healthy controls who were admitted to the Namazi Hospital affiliated to the Shiraz University of Medical Sciences, Shiraz, Iran, were enrolled between years 2012 and 2013. Blood samples treated with EDTA were collected from each patient with leukemia and controls. The existence of TT Virus infection was analyzed using the semi-nested PCR method. The immunological prevalence of HBV and HCV infections were evaluated using HBs-Ag and HCV-Ab ELISA based protocols, respectively. Active CMV infection was also evaluated using an immunofluorescence method. Also risk factors of leukemia and viral infections were statistically analyzed in patients with leukemia.Results:The TT Virus infection was significantly found in 40 of 95 (42.1%) and 12 of 100 (12%) patients with leukemia and controls, respectively. The HBs-Ag and HCV-Ab were detected in 27 of 95 (28.4%) and 18 of 69 (26.1%) patients with leukemia but were not found in the controls. Active CMV infection was also found in 11 of 69 (16%) patients and none of the controls. Significant co-infection of TT Virus was found with HBV (15 of 40; 37.5%), HCV (14 of 40; 35%) and CMV (7 of 40; 17.5%) in patients with leukemia.Conclusions:Confirmation of the significantly higher frequency of TT Virus, HBV, HCV and CMV single infection and their co-infection in patients with leukemia compared with healthy controls, emphasizes the determinative role of TT Virus pathogenesis in clinical outcomes observed in patients with leukemia, which requires extensive evaluation by further studies.

Prevalence of TT virus infection in Italian-dialysis patients

A novel DNA virus, transfusion-transmitted virus (TTV) is identified from the serum of a patient from acute hepatitis non-A-E. Few reports have been published on patients with renal disease. Patients on dialysis were at high risk of blood-borne viral infections and little is known about the prevalence of this virus in dialysis patients. In order to verify the prevalence of infection from TTV in these patients, we have examined the incidence of TTV in Italian patients with dialysis. Serum samples of 85 patients and 65 healthy individuals were examined. In order to evidence the presence of the TTV virus, a method of the seminested polymerase chain reaction (PCR) with TTV-specific primers derives from the N22 region deIl'ORF-1 of the virus has been used and products were analyzed by agarose-gel electrophoresis. All serum samples were also analyzed to markers HBV and HCV. The prevalence of TTV DNA in dialysis patients [35/85 (41.7%)] was significantly higher than in healthy population [7/65 (10.7%)]. Among TTV positive dialysis patients, HCV coinfection was present in six cases. The positivity rate for TTV-DNA tends to increase with age. Transfusion-transmitted virus had a high prevalence in Italian-dialysis patients. In our study the virus did not have an important clinical effect on patients; but remains the possibility that it may aggravate liver disease caused by HCV. However, the question of whether TTV infection might have a possible effect on dialysis patients requires further investigation in larger groups.

Prevalence of TT Virus Infection in Voluntary Blood Donors and Patients on Maintenance Hemodialysis in Tabriz, Iran

Prevalence of TT Virus Infection in Voluntary Blood Donors and Patients on Maintenance Hemodialysis in Tabriz, Iran

Clinical significance of T.T. virus infection in maintenance hemodialysis patients of an endemic area for hepatitis C infection

Clinical significance of TTV infection was analyzed in Egyptian hemodialysis (HD) patients. Forty-seven Egyptian patients on maintenance HD and 50 age-matched volunteer blood donors were investigated. TT virus (TTV) DNA detection and genotyping were performed using a semi-nested polymerase chain reaction with specific primers. The prevalence of TTV DNA in patients on HD (66%) was significantly ( P<0.001) higher than in blood donors (24%) with genotype 1b predominance (89%) in both. Clinical background including mean age, sex, history of blood transfusion, and positive markers for either hepatitis B virus (HBV) or hepatitis C virus (HCV) did not differ between TTV DNA positive and negative HD patients. However, the mean duration of HD was significantly ( P=0.032) shorter in the TTV positive patients (28±19 months) than in the negative ones (45±34 months). Mean alanine aminotransferase level in patients with HCV infection alone (41±24 IU/l) did not differ from that in patients with both co-infection (33±28 IU/l), but was significantly higher than that in patients with TTV infection alone (26±10 IU/l). Occurrence of chronic hepatic changes in patients with TTV infection alone (7%) was significantly less common than those with HCV infection alone (100%, P<0.001) or those with both co-infection (100%, P<0.001). Serum level of HCV core protein was similar between patients with HCV infection alone and those with co-infection with TTV. In conclusion, the prevalence of TTV infection is high in Egyptian patients on regular HD, especially with shorter duration on HD. No clinical significance of TTV virus could be elicited in HD Egyptian patients; neither it showed any clinical impact as a co-infection with HCV.

Lack of transmission of TT virus through immunoglobulins.

A high prevalence of TT virus (TTV) infection has been found in patients who received blood or blood components. Viral DNA was demonstrated in commercial preparations of FVIII and F IX, but very few data have been reported on immunoglobulins. The risk of TTV infection associated with intramuscular or IV immunoglobulin administration is unclear. The prevalence of TTV infection in a group of patients undergoing lifelong therapy because of congenital immunodeficiency has been evaluated in a long term follow-up (median, 6 years). Seventeen patients with congenital immunodeficiency receiving monthly administration of IVIG were included in the study. TTV DNA was repeatedly evaluated by PCR in serum samples from each patient during the follow-up. Research of antibodies against TTV was not applicable, as the patients studied were unable to produce antibodies. The presence of TTV was also evaluated in 15 IVIG lots. The total amount of immunoglobulin administered was 18,773 g. TTV infection was not found in any patients included in the study. None of the 15 immunoglobulin preparations analyzed was found positive for TTV DNA. Despite the high prevalence of TTV in blood donors, commercial immunoglobulins are safe and unable to transmit TTV.

TT virus infection in patients with primary hypogammaglobulinaemia: natural history and relationship to liver disease in the immunocompromised host.

TT virus (TTV) is a recently discovered human DNA virus with worldwide distribution, but with no clear disease association. The possibility of an enhanced TTV virulence in patients with immunodeficiencies has not yet been investigated but is of particular interest because other viruses have been demonstrated to cause severe and rapid liver disease in such patients. Here we analysed the characteristics of TTV infection in a large cohort of patients with primary hypogammaglobulinaemia (PHG) and whether TTV has a role in the frequently observed cryptogenic liver disease in these patients. 83 Norwegian patients with PHG (serum immunoglobulin G < 2 g/L), receiving substitution treatment with immunoglobulins, were followed regularly for median 10.2 years (range 2-30). TTV DNA was sought in serum samples and three immunoglobulin preparations by polymerase chain reaction; TTV DNA quantitation, DNA sequencing and phylogenetic analysis were performed in selected samples. TTV DNA was detected in 27 of 83 (32.5%) patients and was not associated with a particular type of PHG. The prevalence of TTV infection was dependent on intravenous immunoglobulin administration, duration of therapy and patient's age. TTV DNA was found in two of three currently used immunoglobulin preparations. In the longitudinal study, whether TTV was cleared or newly acquired had no impact on liver function tests and no particular TTV strain was found in patients with more severe liver disease. TTV infection is common in patients with PHG. Treatment with immunoglobulins has a role in the transmission of TTV in these patients. However, we found no evidence of TTV-induced liver disease in this group of immunocompromised patients.

TT Virus Infection in Patients with Primary Hypogammaglobulinaemia: Natural History and Relationship to Liver Disease in the Immunocompromised Host

Background: TT virus (TTV) is a recently discovered human DNA virus with worldwide distribution, but with no clear disease association. The possibility of an enhanced TTV virulence in patients with immunodeficiencies has not yet been investigated but is of particular interest because other viruses have been demonstrated to cause severe and rapid liver disease in such patients. Here we analysed the characteristics of TTV infection in a large cohort of patients with primary hypogammaglobulinaemia (PHG) and whether TTV has a role in the frequently observed cryptogenic liver disease in these patients. Methods: 83 Norwegian patients with PHG (serum immunoglobulin G < 2 g/L), receiving substitution treatment with immunoglobulins, were followed regularly for median 10.2 years (range 2-30). TTV DNA was sought in serum samples and three immunoglobulin preparations by polymerase chain reaction; TTV DNA quantitation, DNA sequencing and phylogenetic analysis were performed in selected samples. Results: TTV DNA was detected in 27 of 83 (32.5%) patients and was not associated with a particular type of PHG. The prevalence of TTV infection was dependent on intravenous immunoglobulin administration, duration of therapy and patient's age. TTV DNA was found in two of three currently used immunoglobulin preparations. In the longitudinal study, whether TTV was cleared or newly acquired had no impact on liver function tests and no particular TTV strain was found in patients with more severe liver disease. Conclusions: TTV infection is common in patients with PHG. Treatment with immunoglobulins has a role in the transmission of TTV in these patients. However, we found no evidence of TTV-induced liver disease in this group of immunocompromised patients.

High prevalence of TT virus infection in French blood donors revealed by the use of three PCR systems.

The purpose of this study was to determine the prevalence of TT virus (TTV) infection in voluntary blood donors in Southeastern France. The sera of 289 blood donors were tested for the presence of TTV DNA by two PCR systems detecting genes located in the 5' UTR (primer set A [Set A]) and the open reading frame (ORF2) (primer set B [Set B]) of the viral genome. A randomized sample of 40 blood donors was also tested by a nested-PCR system in the ORF1 by use of primer set C (Set C). Donors were questioned for possible risk factors for virus transmission. In the entire population studied, 30.8 percent of blood donors tested positive with both Sets A and B, and 70.6 percent with at least one set. In the sample tested with three sets of primers, 27.5 percent of blood donors were positive in testing with all PCR systems and 80 percent with at least one system. The specificity of TTV DNA amplification was confirmed by sequencing 10 PCR products obtained with each set of primers. Statistical analysis revealed that the prevalence of TTV reactivity increased with age. The high prevalence of TTV reactivity and the absence of a pathologic condition or risk factors obviously associated with the infection in blood donors suggest that there is no need for systematic detection of TTV infection before blood donation. Further studies are required to determine if TTV isolates can be responsible for a pathologic condition in humans after blood transfusion.

Prevalence of TT virus infection in blood donors with elevated ALT in the absence of known hepatitis markers.

Recently a novel DNA virus (TT virus) has been identified in Japan and shown to be associated with elevated aminotransferase levels after blood transfusion. The exact role of TTV in the pathogenesis of liver disease is yet to be established. Our aim was to determine the prevalence and role of TTV in the pathogenesis of elevated transaminases in healthy blood donors in the absence of markers for viral hepatitis A-C. Stored sera were collected from 99 healthy blood donors with elevated alanine amino transferase (ALT) values that were discovered at the time of blood donation. A total of 146 samples were obtained from healthy donors with normal ALT values who were used as controls. None of the patients or controls had a history of blood transfusion or had clinical signs of acute or chronic hepatitis. Serological markers for hepatitis A, hepatitis B, and hepatitis C viruses were negative. TTV DNA was amplified and detected using polymerase chain reaction followed by gel electrophoresis. Five of 99 (5%) samples obtained from donors with elevated ALT had TTV DNA detected by PCR, as compared to one of 146 (0.7%) of those with normal ALT (p = 0.006). Among those with elevated ALT, mean ALT values in patients with TTV (296 +/- 305 U/L) were higher than in patients without TTV (95 +/- 37 U/L), but the difference was not statistically significant (p = 0.08). The two samples with highest ALT values (both >450 U/L) were among the five samples with detectable TTV DNA in serum. Although TTV is not likely to explain the majority of elevated ALT cases in otherwise healthy blood donors, TTV infection may potentially be associated with some cases. Based on these findings, we propose that the role of TTV in the pathogenesis of acute and chronic liver diseases merits further investigation.

Prevalence of TT virus infection in blood donors with elevated ALT in the absence of known hepatitis markers

OBJECTIVE: Recently a novel DNA virus (TT virus) has been identified in Japan and shown to be associated with elevated aminotransferase levels after blood transfusion. The exact role of TTV in the pathogenesis of liver disease is yet to be established. Our aim was to determine the prevalence and role of TTV in the pathogenesis of elevated transaminases in healthy blood donors in the absence of markers for viral hepatitis A-C. METHODS: Stored sera were collected from 99 healthy blood donors with elevated alanine amino transferase (ALT) values that were discovered at the time of blood donation. A total of 146 samples were obtained from healthy donors with normal ALT values who were used as controls. None of the patients or controls had a history of blood transfusion or had clinical signs of acute or chronic hepatitis. Serological markers for hepatitis A, hepatitis B, and hepatitis C viruses were negative. TTV DNA was amplified and detected using polymerase chain reaction followed by gel electrophoresis. RESULTS: Five of 99 (5%) samples obtained from donors with elevated ALT had TTV DNA detected by PCR, as compared to one of 146 (0.7%) of those with normal ALT ( p = 0.006). Among those with elevated ALT, mean ALT values in patients with TTV (296 ± 305 U/L) were higher than in patients without TTV (95 ± 37 U/L), but the difference was not statistically significant ( p = 0.08). The two samples with highest ALT values (both >450 U/L) were among the five samples with detectable TTV DNA in serum. CONCLUSIONS: Although TTV is not likely to explain the majority of elevated ALT cases in otherwise healthy blood donors, TTV infection may potentially be associated with some cases. Based on these findings, we propose that the role of TTV in the pathogenesis of acute and chronic liver diseases merits further investigation.

TT virus infection in hemodialysis patients

OBJECTIVE: Recently, TT virus (TTV), associated with posttransfusion hepatitis, was discovered. Prevalence of TTV infection in maintenance hemodialysis (HD) units and its pathogenicity to liver was investigated. METHODS: A total of 115 patients on HD were assessed for presence of serum TTV. DNA was purified from sera, and nested polymerase chain reaction was done for the detection of TTV DNA. RESULTS: TTV was detected in 59 patients on HD (51.3%), as compared with healthy blood donors (15 of 91 [16.5%], p < 0.0001). Serum HCV RNA and HBs antigen were positive in 16 and three patients, respectively. The prevalence rate of TTV was already 58.3% in the patients on HD for only 1 yr, and did not change according to the duration of HD until 15 yr on HD. TTV was positive in 51.2% (43 of 84) of the patients with history of blood transfusion, and in 51.6% (16 of 31) of those without it. In HCV-negative patients, alanine aminotransferase (ALT) levels of TTV-positive patients were similar to those of TTV-negative patients. Contrarily, in HCV-positive patients, ALT levels were more frequently ≥15 IU/L in TTV-positive patients (14 of 18) than in TTV-negative patients (five of 15) ( p < 0.05). CONCLUSIONS: TTV infection is remarkably prevalent in patients on HD and in healthy blood donors. It is suggested that TTV generally does not cause liver disease by itself, but there remains the possibility that TTV may aggravate liver disease caused by HCV.

TT virus infection in hemodialysis patients.

Recently, TT virus (TTV), associated with posttransfusion hepatitis, was discovered. Prevalence of TTV infection in maintenance hemodialysis (HD) units and its pathogenicity to liver was investigated. A total of 115 patients on HD were assessed for presence of serum TTV. DNA was purified from sera, and nested polymerase chain reaction was done for the detection of TTV DNA. TTV was detected in 59 patients on HD (51.3%), as compared with healthy blood donors (15 of 91 [16.5%], p < 0.0001). Serum HCV RNA and HBs antigen were positive in 16 and three patients, respectively. The prevalence rate of TTV was already 58.3% in the patients on HD for only 1 yr, and did not change according to the duration of HD until 15 yr on HD. TTV was positive in 51.2% (43 of 84) of the patients with history of blood transfusion, and in 51.6% (16 of 31) of those without it. In HCV-negative patients, alanine aminotransferase (ALT) levels of TTV-positive patients were similar to those of TTV-negative patients. Contrarily, in HCV-positive patients, ALT levels were more frequently > or =15 IU/L in TTV-positive patients (14 of 18) than in TTV-negative patients (five of 15) (p < 0.05). TTV infection is remarkably prevalent in patients on HD and in healthy blood donors. It is suggested that TTV generally does not cause liver disease by itself, but there remains the possibility that TTV may aggravate liver disease caused by HCV.

Low risk of TT virus (TTV) infection in medical workers

The rate of infection with TT virus (TTV), a novel single-strand DNA virus was evaluated and the clinical and laboratory features in affected Japanese medical workers were analysed. TTV DNA was measured in 356 medical workers and in 150 age-matched controls using a semi-nested polymerase chain reaction. TTV DNA was detected in 62 of 356 medical workers (17·4%). There were no differences in the prevalence of TTV infection between medical workers and controls (18·9%) and in the characteristics of medical workers with TTV infection and medical workers without it, except that the mean age of patients with TTV infection was higher than that of patients without TTV. The medical workers were drawn from three groups: medical doctors, nurses and clinical laboratory technicians. There was no statistically significant difference between the rate of TTV infection in the three groups. These findings suggest that the risk of TTV infection in medical workers is low and not related to liver dysfunction.

High prevalence of TT virus infection in healthy children and adults and in patients with liver disease in Taiwan.

A newly identified DNA virus, named TT virus (TTV), was found to be related to transfusion-associated hepatitis. We conducted the following experiments to evaluate its pathogenic role in liver disease and potential modes of transmission. We used PCR to detect TTV DNA in serum. The rates of TTV viremia in 13 patients with idiopathic acute hepatitis, 14 patients with idiopathic fulminant hepatitis, 22 patients with chronic hepatitis, and 19 patients with cirrhosis of the liver were 46, 64, 55, and 63%, respectively, and were not significantly different from those in 50 healthy control subjects (53%). PCR products derived from seven patients with liver disease and three healthy controls were cloned and then subjected to phylogenetic analyses, which failed to link a virulent strain of TTV to severe liver disease. TTV infection was further assessed in an additional 148 subjects with normal liver biochemical tests, including 30 newborns (sera collected from the umbilical cord), 23 infants, 16 preschool children, 21 individuals of an age prior to that of sexual experience (aged 6 to 15 years), 15 young adults (aged under 30 years), and 43 individuals older than 30 years. The rates of TTV viremia were 0, 17, 25, 33, 47, and 54%, respectively. These findings suggest that TTV is transmitted mainly via nonparenteral daily contact and frequently occurs very early in life and that TTV infection does not have a significant effect on liver disease.

Prevalence of TT virus infection in US blood donors and populations at risk for acquiring parenterally transmitted viruses.

Two overlapping sets of TT virus (TTV)-specific polymerase chain reaction primers were used to test for presence of TTV, which was found in approximately 10% of US volunteer blood donors, 13% of commercial blood donors, and 17% of intravenous drug abusers. The rate of TTV infection among US non-A, non-B, non-C, non-D, non-E hepatitis patients was only 2%. Among commercial blood donors and intravenous drug abusers, only 1%-3% of the TTV-positive individuals were coinfected with GB virus C (GBV-C), a parenterally transmitted virus. This suggests that GBV-C and TTV may have different routes of transmission. Comparison of the sensitivities of 2 TTV polymerase chain reaction (PCR) primer sets showed that the majority of samples were detected with only 1 of the 2 sets. Therefore, previous studies in which only a single PCR primer pair was used may have significantly underestimated the true prevalence of TTV.

High prevalence of TT virus infection in Brazilian blood donors

A recent report has described the molecular cloning and characterization of a novel, single-stranded DNA virus, named TT virus (TTV), which was present in the sera of Japanese patients with posttransfusion hepatitis of unknown etiology [Okamoto et al. (1998) Hepatology Research 10:1–16]. Using a nested polymerase chain reaction assay, sera from Brazilian patients with acute non A-C hepatitis and blood donors were examined for the presence of TTV DNA sequences. Thirty-seven of 52 (71%) patients with acute non A-C hepatitis and 45 of 72 (62%) blood donors were found to have TTV sequences in their sera. Such a high proportion in blood donors indicated that TTV infection is common in the general Brazilian population. Partial nucleotide sequences (326 bases in open reading frame 1) from seven isolates were determined. By phylogenetic analysis, four TTV strains were classified into the genomic subgroup G1a described previously. The three others belonged to subgroup G1b. Sequence homologies between strains belonging to a same subgroup were 92.9–99.1%, whereas homologies of 85.9–90.2% were calculated between isolates from different subgroups. J. Med. Virol. 57:259–263, 1999. © 1999 Wiley-Liss, Inc.

High prevalence of TT virus infection in Brazilian blood donors

A recent report has described the molecular cloning and characterization of a novel, single-stranded DNA virus, named TT virus (TTV), which was present in the sera of Japanese patients with posttransfusion hepatitis of unknown etiology [Okamoto et al. (1998) Hepatology Research 10:1-16]. Using a nested polymerase chain reaction assay, sera from Brazilian patients with acute non A-C hepatitis and blood donors were examined for the presence of TTV DNA sequences. Thirty-seven of 52 (71%) patients with acute non A-C hepatitis and 45 of 72 (62%) blood donors were found to have TTV sequences in their sera. Such a high proportion in blood donors indicated that TTV infection is common in the general Brazilian population. Partial nucleotide sequences (326 bases in open reading frame 1) from seven isolates were determined. By phylogenetic analysis, four TTV strains were classified into the genomic subgroup G1a described previously. The three others belonged to subgroup G1b. Sequence homologies between strains belonging to a same subgroup were 92.9-99.1%, whereas homologies of 85.9-90.2% were calculated between isolates from different subgroups.

TT virus infection in an area of high-endemicity for hepatitis C

TT virus (TTV) was recently identified as a candidate for a new hepatitis virus. In the present study, the clinical features and transmission routes of TTV infection were analyzed in an area highly endemic for hepatitis C virus (HCV) infection, and compared to those in an area not endemic. A total of 400 inhabitants were selected randomly from those who were medically screened for liver disease in 1993; 200 were from the high-endemicity area, and the other 200 were from the control area. TTV DNA in serum was tested by a semi-nested polymerase chain reaction. The prevalence of TTV DNA was 58% (116/200) in the high-endemicity area, and was significantly ( P=0.0083) higher than that in the control area (43%, 85/200). Age specific prevalence of TTV DNA was significantly ( P=0.0007) higher in individuals over 60 years old (68.8%) than in those under 60 (45.1%) in the high-endemicity area, but was similar among the age groups in the control area. TTV infection was not associated with neither HCV and hepatitis G virus (HGV) infections nor histories of surgical operation, blood transfusion and folk remedies in both areas. In the high-endemicity area, the prevalence of TTV DNA was significantly ( P=0.0311) lower in individuals with any HCV markers (25%) than in those without it (39%). The elevation of liver enzymes in serum was dependent on HCV viremia but not on TTV viremia. In conclusion, the prevalence of TTV infection was as high as 58% in the high-endemicity area for HCV infection. The infection pattern for TTV was different from that of HCV and HGV. TTV infection showed a reciprocal association with HCV infection, and had limited pathogenetic effect on hepatitis.