Torque Teno Virus plasma DNA load: a novel prognostic biomarker in CAR-T therapy

Torque Teno Virus (TTV) is a single-stranded circular DNA virus which has been identified as a surrogate marker of immune competence in transplantation. In this study we investigated the dynamics of plasma TTV DNAemia in 79 adult patients undergoing chimeric antigen receptor T-cell (CAR-T) therapy for relapsed or refractory large B-cell lymphoma, also evaluating the impact of TTV on immunotoxicities, response and survival outcomes. After lymphodepleting therapy, TTV DNA load was found to decrease slightly until reaching nadir around day 10, after which it increased steadily until reaching maximum load around day 90. TTV DNA load < 4.05 log10 copies/ml at immune effector cell-associated neurotoxicity syndrome (ICANS) onset identified patients at risk of progressing to severe forms of ICANS (OR 16.68, P = 0.048). Finally, patients who experienced falling or stable TTV DNA load between lymphodepletion and CAR-T infusion had better progression-free survival than those with ascending TTV DNA load (HR 0.31, P = 0.006). These findings suggest that TTV monitoring could serve as a surrogate marker of immune competence, enabling predictions of CAR-T efficacy and toxicity. This could pave the way for the development of TTV-guided therapeutic strategies that modulate clinical patient management based on plasma TTV load, similar to suggested strategies in solid organ transplant recipients.

Quantification of Torque Teno Virus Load to Monitor Short-term Changes in Immunosuppressive Therapy in Kidney Transplant Recipients

BACKGROUND

Quantification of torque teno virus (TTV) has been proposed as a surrogate parameter to monitor immunocompetence in kidney transplant recipients (KTRs) early after transplantation. However, its use in monitoring short-term changes of immunosuppression in KTRs late after transplantation requires further investigation.

METHODS

In this post hoc analysis, we quantified TTV load in sera of 76 KTRs, with 43 pausing mycophenolic acid (MPA) 1 wk before to 4 wk after COVID-19 vaccination to increase vaccine response. TTV load was quantified before, 4 wk, and 3 mo postvaccination. Results were compared to 33 KTRs with continued standard immunosuppressive therapy and with 18 hemodialysis as well as 18 healthy control subjects.

RESULTS

TTV load before vaccination was with a median (interquartile range) of 1.39 × 10 4 copies/milliliter (c/mL) (9.17 × 10 1 -2.66 × 10 5 c/mL) highest in KTRs compared to 1.73 × 10 3 c/mL (1.07 × 10 3 -1.31 × 10 4 c/mL) in hemodialysis patients and 1.53 × 10 2 c/mL (6.38-1.29 × 10 3 c/mL) in healthy controls. In KTRs with MPA withdrawal, TTV load decreased significantly from a median (interquartile range) of 1.11 × 10 4 c/mL (4.75 × 10 2 -1.92 × 10 5 c/mL) to 5.24 × 10 3 c/mL (6.92 × 10 2 -6.91 × 10 4 c/mL) 4-5 wk after initiation of MPA withdrawal ( P = 0.003). In patients with MPA withdrawal, TTV load was significantly inversely correlated with COVID-19 or SARS-CoV-2-specific antibodies 4 wk and 3 mo postvaccination ( P = 0.009 and P = 0.004).

CONCLUSIONS

TTV load reflects changes in immunosuppressive therapy even late after transplantation, supporting its use to monitor immunocompetence in KTRs.

Natural recombination of the torque teno canis virus within the ORF1, -2, and -3 genes and the untranslated region

The torque teno canis virus (TTCaV) was first reported in 2001 and it shares similarities with the known Torque teno virus (TTV) in terms of genomic organization and putative transcriptional features. It is a single-stranded DNA virus characterized by high rates of recombination and nucleotide substitution, like RNA viruses. Studies reported recombination events in torque teno virus; however, there is limited reporting of TTCaV reorganization events. This study screened fecal samples from domestic dogs in Henan Province. There was a positivity rate of 16.5% (19/115) for TTCaV. Four nearly complete TTCaV genomes, namely Canine/HeNan/4, 5, 6, and 13/2019, were obtained from the 19 positive fecal samples, whose genome sequence was obtained using gap-filling PCR. Sequence analysis revealed two unique amino acid mutation sites in the TTCaV strains, K278Q (compared with the first isolate Cf-TTV10 in Japan) and V/L268I (compared with the TTCaV strain from southern China). Subsequently, 17 near full-length TTCaV genome sequences were subjected to phylogenetic and recombination detection program analyzes. We obtained evidence supporting recombination events in the Chinese TTCaV strains. These findings suggest that mutation and recombination occurred in the three individual gene segments (ORF1, ORF2, ORF3) and the untranslated region, an area of major recombination in the Chinese TTCaV strain GX265 genome. Interestingly, the TTCaV strain (Canine/HeNan/6/2019) was a major parent involved in the genetic recombination of the GX265 strain. This study provides insights into the genetic variability and evolution of TTCaV.

The Time-Dependent Association of Torque Teno Virus Load with the Level of SARS-CoV-2 S1 IgG Antibodies Following COVID-19 Vaccination in Kidney Transplant Recipients

Kidney transplant recipients (KTR) show an impaired humoral immune response to COVID-19 vaccination due to their immunocompromised status. Torque teno virus (TTV) is a possible marker of immune function. This marker may be helpful in predicting the immune response after COVID-19 vaccination in order to decide which vaccination strategy should be applied. We therefore investigated whether TTV load is associated with the humoral response after COVID-19 vaccination. Of the KTR who participated in two prospective vaccination studies and received two to four doses of the mRNA-1273 COVID-19 vaccine, 122 were included. TTV load was measured prior to vaccination, and S1 IgG antibody levels were measured 28 days after vaccination. TTV load was independently inversely associated with S1 IgG antibodies after COVID-19 vaccination (B: -2.19 (95% CI: -3.6--0.8), p = 0.002). Interestingly, we found a significant interaction between TTV load and time after transplantation (p = 0.005). When patients were longer after transplantation, TTV load was less predictive for S1 IgG antibody response after vaccination compared to patients that were shorter after transplantation. Our data suggest that TTV load is a good marker in predicting COVID-19 vaccination antibody response and may be helpful in selecting a strategy shortly after transplantation. However, this marker should be handled with caution longer after transplantation.

Immune monitoring of prevalent kidney transplant recipients using Torque Teno Virus: Protocol for a single-centre prospective cohort study

INTRODUCTION

Kidney transplant recipients (KTRs) suffer from immunosuppression-related adverse events (iRAEs), such as infections and malignancy from chronic immunosuppression, but are also at risk of graft loss from rejection with underimmunosuppression. Biomarkers that predict both iRAEs and rejection while allowing individualisation of immunosuppression exposure are lacking. Although plasma viral DNA levels of torque teno virus (TTV), a widely prevalent, non-pathogenic virus, have been shown to predict both iRAE and rejection in newly transplanted KTRs within the first year after transplant, its role for prevalent KTRs on stable immunosuppression is less clear.This study aims to determine the prognostic value of TTV levels for severe infections (defined as infections requiring hospitalisation) in prevalent KTRs on stable immunosuppression for at least 3 months and compare it against that of other commonly available biomarkers. The study also aims to explore the relationship between TTV levels and factors affecting the 'net state of immunosuppression' as well as other clinical outcomes.

METHODS AND ANALYSIS

This is a single-centre, prospective, observational cohort study of 172 KTRs on stable immunosuppression for more than 3 months. TTV levels will be measured using the TTV R-GENE kit upon recruitment when study subjects are admitted and when kidney allograft biopsies are performed. Subjects will be monitored for iRAEs and rejection for at least 12 months. The relationship between TTV load and clinical outcomes such as severe infections will be analysed and compared against that from other common biomarkers and previously published predictive scores.

ETHICS AND DISSEMINATION

The study was approved by the SingHealth Centralised Institutional Review Board (2023/2170). The results will be presented at conferences and submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05836636.

TTV viral load as a predictor of antibody response to SARS COV-2 vaccination

The measure of torquetenovirus (TTV) viremia is widely recognized as an optimal biomarker of an individual immune status. In the context of COVID-19, the predictive role of TTV load with regard to vaccine response has also been demonstrated, suggesting other intriguing applications for this widespread anellovirus.

Transfusion transmitted virus and dengue virus among healthy blood donors: A prevalence report from Jordan

Transfusion transmitted virus (TTV) is thought to contribute to non-A non-E hepatitis and other diseases. Dengue virus (DENV) is a serious mosquito-borne pathogen. Reports on TTV and DENV in Jordan and the Middle East and North Africa region are limited. Herein, the prevalence of TTV antigen and anti-DENV IgG antibodies among apparently healthy blood donors from Northern Jordan and the Northern Agwar region of Jordan was investigated using an enzyme-linked immunosorbent assay. Chi-square test and binary logistic regression were used to correlate positivity with possible infection risk factors (age, sex, residence location, and occupation). One hundred ninety apparently healthy blood donors were included in the study (age 18 - 54 years). TTV antigen was detected in 17.9% of the samples. Lower antigen positivity was observed among Agwar residents than non-residents (7.1% vs 24.5%; chi-square test P < 0.001), which was confirmed by regression analysis (odds ratio 0.262 [95% confidence interval 0.086-0.805]; P = 0.019). Antigen positivity did not differ by age, sex, or occupation. Seropositivity for anti-DENV IgG was 17.9%. Seropositivity did not differ by age, sex, or occupation. Higher seropositivity was observed among Agwar residents than non-residents (36.1% vs 9.4%; chi-square test P < 0.001), which was confirmed by regression analysis (odds ratio 5.420 [95% confidence interval 2.377-12.359]; P < 0.001). Overall, low TTV antigen prevalence and DENV seroprevalence were found among blood donors from Northern Jordan and the Northern Agwar region of Jordan.

Efficacy of Different Testing Scenarios in Reducing Transfusion-Transmitted Hepatitis B Virus (TT-HBV) Infection Risk

The efficacy of different screening scenarios in reducing hepatitis B virus (HBV) transmission risk as compared to the risk without screening was modeled in 9,337,110 donations from four geographical regions that had been subjected to hepatitis B surface antigen (HBsAg) and individual donation nucleic acid amplification testing (ID-NAT). We used the Weusten models for estimating infectivity risk for Red Blood Cell (RBC) transfusions in eight HBV infection stages and then evaluated multiple screening strategies based on minipool (MP) and ID-NAT options of different sensitivity for their efficacy in reducing this risk. The efficacy in reducing HBV transmission risk by screening scenarios across the regions varied between 81% (HBsAg only) and 99.2% (ID-NAT and anti-HBc). Highly sensitive ID-NAT alone achieved a slightly higher risk reduction (97.6−99.0%) than minipool of 6 donations (MP6)-NAT in combination with HBsAg and anti-HBc (96.3−98.7%). In ID-NAT screened lapsed and repeat donors, the additional risk removed by HBsAg testing was minimal (<0.1%). The modeling outcomes in this and two previous reports using this multi-regional database suggest that one could consider an ID-NAT alone testing scenario as an alternative to MP-NAT and serology-based testing algorithms and restrict serologic testing to first-time donors only.

Phylogenetic analysis of torque teno virus in Romania: possible evidence of distinct geographical distribution

Torque teno virus (TTV) is highly prevalent, but little is known about its circulation in humans. Here, we investigated the geographical distribution and phylogeny of TTV in Romania. A fragment of TTV untranslated region B was sequenced in samples from volunteers across the country. Additional sequences from dialyzed patients were also included in the study. Phylogenetic analysis showed that more than 80% of Romanian sequences clustered with isolates assigned to the species Torque teno virus 1 and Torque teno virus 3 (former genogroup 1), and this analysis discriminated between isolates from the North-East and West regions. Further studies assessing the pathogenic potential of TTV isolates should employ analysis based on genomic regions with phylogenetic resolution below the species level.

Obesity is associated with a higher Torque Teno viral load compared to leanness

INTRODUCTION

Obesity affects a rising proportion of the population and is an important risk factor for unfavorable outcomes in viral disease including severe acute respiratory syndrome coronavirus 2- associated diseases. Torque Teno virus (TTV) is a ubiquitous and apathogenic virus which reflects the immune function of its host. The aim of this study was to investigate the association between obesity and TTV load - an indirect marker of compromised viral immune response.

METHODS

TTV was quantified by TTV R-GENE^® PCR in a total of 89 participants of which 30 were lean (BMI <25 kg/m²) and 59 were obese (BMI >30 kg/m²). For 38 subjects, follow-up was available after bariatric surgery.

RESULTS

TTV load was higher in individuals with obesity (median 2.39, IQR: 1.69-3.33 vs. 1.88, IQR 1.08-2.43 log10 copies/mL; p = 0.027). Multivariable linear modeling revealed an independent association between TTV load and obesity. TTV was positively correlated with waist-to-hip ratio and inversely with 25OH vitamin D levels. Interleukin 6 and fasting insulin resistance were confounders of the association between TTV and obesity, while age was an effect modifier. TTV load increased by 87% (95% CI 2-243%) in the year following bariatric surgery.

DISCUSSION

A higher TTV load in obese individuals may reflect compromised immune function and thus might serve for risk stratification of unfavorable outcomes during infectious disease, including coronavirus disease 2019, in this population. Our data warrant further analysis of TTV-based risk assessment in obese individuals in the context of infectious disease-associated outcomes.

Transfusion-Transmitted Hepatitis A Virus, France, 2018

We report a transfusion-transmitted hepatitis A virus infection in an immunocompromised patient in France, detected shortly after a transfusion of pathogen-reduced pooled platelets. This case raises questions about the efficacy of donor screening methods. Additional safety measures, such as routine donation screening, should be considered.

Kinetics of Torque Teno virus DNA in stools may predict occurrence of acute intestinal graft versus host disease early after allogeneic hematopoietic stem cell transplantation

Torque Teno virus (TTV) DNA load in blood may act as a marker of immune competence after allogeneic hematopoietic stem cell transplant recipients (allo-HSCT). Conflicting data have been reported as to the value of this biomarker for anticipating acute Graft versus host disease (aGvHD) occurrence. Here, we hypothesized that quantitation of TTV DNA load in stool specimens early after allo-HSCT could be used to identify patients at high risk of acute intestinal graft versus host disease (aIGvHD). In this prospective two-center study, we recruited a total of 83 nonconsecutive adult patients undergoing allo-HSCT. The study period comprised the first 120 days after allo-HSCT. TTV DNA was quantitated in paired stool samples collected at a median of 2 days prior to cell infusion and at a median of 14 days after allo-HSCT by real-time PCR. Thirty-seven patients developed aGVHD, of whom 25 had aIGVHD (diagnosed at a median of 42 days after allo-HSCT). Median TTV DNA load values in posttransplant stools specimens were comparable (P = .34) in patients with or without subsequent aIGvHD; nevertheless, a falling trajectory (decrease in TTV DNA load >0.5 log₁₀ copies/0.1 g) in paired pretransplant and posttransplant specimens was independently associated with the occurrence of aIGvHD (OR, 5.2; 95% CI, 1.3-21.3; P = .02). Notably, displaying a rising trajectory had a negative predictive value of 87.5% for aIGvHD. In summary, in this hypothesis-generating study, we suggest that the decrease in TTV DNA load from baseline in stool specimens may identify patients at risk of aIGVHD.

Prevalence of emerging torque teno virus (TTV) in drinking water, natural waters and wastewater networks (DWNWWS): A systematic review and meta-analysis of the viral pollution marker of faecal and anthropocentric contaminations

The emerging torque teno virus (TTV) has been identified as a biohazard marker of anthropocentric pollution and contamination in drinking water, natural water and wastewater systems (DWNWWS). Therefore, this study aimed at assessing prevalence of TTV in DWNWWS. The study systematically identified and meta-analyzed published studies on TTV prevalence in DWNWWS hosted in Dimensions, Google Scholar, PubMed, Web of Science, and Scopus databases using a random-effects model and mixed-effects meta-regression model for sensitivity analysis. Furthermore, the meta-analysis was stratified to estimate water type-specific TTV prevalence. The study found a total of 58 articles, of which 13 articles subdivided into 31 studies with 374 TTV positive cases and 862 total sample sizes were systematically reviewed and meta-analyzed. The pooled prevalence of TTV in DWNWWS was 37.18% (95%CI: 23.76-55.55%). Prevalence of TTV was significantly different across water types and it was 56.67% (95%CI: 36.94-75.46%) in wastewater, 26.72% (95%CI: 6.87-52.56%) in river water, and 17.17% (95%CI: 0.54-45.39%) in drinking water. TTV incidence in seawater and groundwater was 0% and 25.0% respectively. Funnel plots constructed and associated statistics of rank correlation test and Egger's regression test in this study, show lack of publication bias in the pooled prevalence of TTV in DWNWWS. Although, sample type (QM(df = 1) = 6.9656, p = 0.0083) and concentration methods (QM(df = 1) = 3.8055, p = 0.0511) significantly moderated and accounted for 15.39% and 6.00% of heterogeneity in the prevalence of TTV in DWNWWS respectively. In conclusion, research focus/monitoring activities on TTV is generally inadequate and potential risk of TTV in DWNWWS is underappreciated in most nations; the analyzed studies were from 7 countries (USA, Japan, Italy, Iran, Germany, Egypt, and Brazil). Finally, inefficient concentration method severely influences the prevalence of TTV in DWNWWS and could give rise to underestimation of TTV and mar TTV-based source-tracking of anthropogenic pollutions.

Detection of dengue, chikungunya, and Zika RNA in blood donors from Southeast Asia

BACKGROUND

Chikungunya (CHIKV), dengue (DENV), and Zika (ZIKV) viruses are of concern due to the potential of transfusion transmission in blood, especially in regions such as Southeast Asia where the viruses are endemic. The recent availability of nucleic acid testing (NAT) to screen blood donations on an automated platform provides the opportunity to detect potentially infectious units in asymptomatic donors.

STUDY DESIGN AND METHODS

Three thousand blood donations from Vietnam and 6000 from Thailand were screened with a real-time polymerase chain reaction (PCR) test (cobas CHIKV/DENV, Roche Diagnostics, Indianapolis, IN) and equal numbers on cobas Zika (Roche Diagnostics). Reactive samples were tested by alternative NAT with resolution of discordant results by heminested PCR. Throughput of simultaneous testing of the two assays on the cobas 8800 system (Roche Diagnostics) was evaluated.

RESULTS

In Vietnam, 9 of 3045 samples were reactive for DENV and all were confirmed, for a prevalence (with 95% confidence interval [CI]) of 0.296% (0.135-0.560). In Thailand, 2 of 6000 samples were reactive for CHIKV, 4 of 6000 for DENV, and 1 of 6005 for ZIKV, and all confirmed. The prevalence of CHIKV is 0.033% (0.004-0.120), DENV 0.067% (0.018-0.171), and ZIKV 0.017% (0.000-0.093). The overall specificity for the cobas CHIKV/DENV and cobas Zika tests was 100% (99.959-100). For the simultaneous assay testing, 960 test results were available in 7 hours and 53 minutes.

CONCLUSION

Detection of CHIKV, DENV, and ZIKV RNA in donor samples in Vietnam and Thailand indicate the presence of the virus in asymptomatic blood donors. The cobas 6800/8800 systems (Roche Molecular Systems, Pleasanton, CA) enable screening blood donations in endemic areas for these viruses together or separately.

[TTV, what is it and what do we know in Mexico?]

The aim of this editorial is to present a brief description of the Torque teno virus’ epidemiology and establish the actuality of their study in México. Also, we mentioned the studies made in México and Yucatán, specifically in the Center of Regional Research “Dr. Hideyo Noguchi” of the Autonomous University of Yucatán.

Men having sex with men in Surakarta, Indonesia: demographics, behavioral characteristics and prevalence of blood borne pathogens

The objectives of this study were to investigate the prevalence of human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), human T-lymphotropic virus types 1 and 2 (HTLV-1/2), Torque teno virus (TTV) and Toxoplasma gondii (T. gondii) infection among men who have sex with men (MSM) in Surakarta, Indonesia, and the risk factors and sexual behavior associated with these infections. A cross sectional study was performed from October 2009 to October 2011 among 143 MSM by face-to-face interviews to complete an interviewer-administered questionnaire. Subjects were tested for ,HIV, HBV, HCV, HDV, HTLV-1/2 and toxoplasma infection using serology and for TTV using molecular detection. The seropositive rates for anti-HIV, HBsAg, anti-HCV, anti-HDV, anti-HTLV-1/2, IgM anti-T. gondii, IgG anti-T, gondii and TTV DNA were 9.1%, 9.8%, 28.0%, 0.7%, 0.7%, 1.4%, 30.8%, and 26.6%, respectively. Risk factors associated with HIV infection were a history of injecting drug use (IDU) [adjusted OR (aOR) 6.0; 95% CI: 1.10-33.01] and a receptive role in sexual activity (aOR 8.1; 95% CI: 1.30-50.04) [corrected]. Having a tattoo (aOR 3.2; 95% CI: 1.28-7.98) and practicing both anal and vaginal sex without a condom (aOR 2.3; 95% CI: 1.06-4.92) were associated with toxoplasma infection. A history of IDU (aOR 32; 95% CI: 5.93-177.93) was associated with TTV infection. The subjects examined in this study were found to be infected with HIV, HBV, HCV, HDV, HTLV-1/2, TTV, and T. gondii. These infections were associated with high-risk behavior.

SEN virus infection in Egyptian patients undergoing maintenance hemodialysis: prevalence and clinical importance

BACKGROUND AND PURPOSE

SEN virus (SENV) is assumed to be responsible for post-transfusion non-A to -E hepatitis. Phylogenetic analysis of SENV has shown 9 different strains. Two strains, SENV-H and SENV-D, were described as possible candidates for post-transfusion hepatitis. This study examined the prevalence of SENV infection and its clinical importance for patients undergoing hemodialysis.

METHODS

Serum samples were obtained from 63 long-term hemodialysis patients, and examined for SENV-H and SENV-D viremia by polymerase chain reaction. Serum samples were also obtained from 20 patients with chronic kidney diseases (CKD) who were not undergoing hemodialysis and from 20 apparently healthy blood donors to act as controls. For SENV screening, a primer pair was used for the conserved ORF1 region among all SENV genotypes from A to I.

RESULTS

SENV infection was significantly more frequent among hemodialysis patients (33/63; 52.4%) and those with CKD (10/20; 50.0%) than among the control participants (2/20; 10.0%) [p = 0.003]. Twenty three of 33 hemodialysis patients had SENV-H or -D, 61% of whom were positive for SENV-H only, 4% were positive for SENV-D only, and 36% were positive for both SENV-H and SENV-D. SENV infection was not associated with age, sex, amount or duration of hemodialysis, or liver function test results. Elevated alanine aminotransferase was significantly associated with HCV viremia, but not with SENV infection.

CONCLUSIONS

Egyptian hemodialysis patients and those with CKD are at higher risk for SENV transmission. SENV-H is more prevalent than SENV-D.

SEN virus infection in Egyptian patients with chronic hepatitis C and patients undergoing hemodialysis

The SEN virus has been tentatively linked to transfusion-associated non-A to E hepatitis. The aim of the present study was to 1) determine the prevalence of SEN virus among Egyptian patients with hepatitis C virus (HCV)-related chronic liver disease and patients undergoing hemodialysis and 2) demonstrate the clinical effect of SEN virus infection on coexistent hepatitis C in terms of severity and probability of developing hepatocellular carcinoma. Polymerase chain reaction was used to detect SEN virus-D and SEN virus-H DNA in serum samples of 74 patients with HCV-related chronic liver disease, 45 uremic patients undergoing maintenance hemodialysis, and 28 healthy controls. SEN virus-D/H DNA was detected in 13.5% of patients with chronic liver disease, 11.1% of patients undergoing hemodialysis, and 7.1% of healthy controls, with no significant differences between patients and the control group. Clinical and biochemical measures did not significantly differ between SEN virus-infected and noninfected patients in the chronic liver disease group or the hemodialysis group. The rate of SEN virus infection was significantly higher in patients with chronic liver disease and hepatocellular carcinoma (33.3%) than in those with chronic liver disease only (8.5%) (P < .05). In conclusion, SEN virus does not seem to be a common infection in Egyptian patients. It has no apparent influence on the severity of coexistent HCV-related chronic liver disease but could be a risk factor for hepatocellular carcinoma in such patients. Further studies are needed to define the etiopathogenic role of SEN virus infection in the development of hepatocellular carcinoma.

[Risk factors of TT virus infection in children up to 3 years]

Significant frequency of TT virus (TTV) infections and its unclear pathogenetic role are purposes for which investigators are interested in theme of spread of the virus. It is considered parenteral way of TTV spread, oral-fecal, droplets, vertical, by breastfeeding and other ways.

THE AIM OF THE STUDY

To estimate the risk of TTV infection by various ways and to asses the risk factors of infection.

MATERIAL AND METHODS

To the analysis were enrolled 55 patients, in 27 (49%) of them we confirmed TTV infection (polymerase chain reaction method with two primers sets). We analyzed frequency of infections dependence on risk factors vertical, parenteral, and enteral infections.

RESULTS

Disturbances in pregnancy or delivery were not connect to frequency of TTV infections. We're not confirming this frequency dependence on number of past hospitalizations but it was dependence between frequency of TTV infections and chronic diseases and mental-physical retardation of children (p=0.077; p=0.01). It was not confirming significant differences in depend on dwelling place. Children from worse social conditions were infected more often (p=0.05). It was not significant dependence between frequency of TTV infections and breastfeeding. It was confirmed that in children of parents with chronic diseases and children with brothers and sisters with chronic diseases are infected more often (for mothers p=0.054; fathers p=0.04, brothers or sisters p=0.062).

CONCLUSIONS

TTV infections are more frequent in infants and young children exposed to often contacts with medical environment, children from poor social conditions and with chronic diseases in near family.

TT virus infection in patients on peritoneal dialysis in Taiwan

Many studies have reported the prevalence of transfusion-transmitted virus (TTV) infection in hemodialysis patients, but few reports studied the prevalence of TTV infection in peritoneal dialysis patients. In this study, we determined the prevalence of TTV in a peritoneal dialysis population in Taiwan and related its prevalence with history of blood transfusion, serum hepatitis B surface antigen (HBsAg), antibody to hepatitis C virus (anti-HCV), and serum aminotransferases (AST and ALT) levels. Serum samples from 47 peritoneal dialysis patients and a control group of 43 patients at health examination were studied for TTV viremia by using polymerase chain reaction. The rate of blood transfusion exposure (p < 0.0001), female gender (p = 0.001), younger age (p = 0.0014), and serum AST level (p = 0.012) were significantly higher in peritoneal dialysis patients. The prevalence of TTV viremia was not significantly different between peritoneal dialysis patients and the control group (23.4% vs. 37.2%). TTV infection was not associated with evident liver diseases in peritoneal dialysis patients, and the infection rate was not different between automated peritoneal dialysis (APD) and continuous ambulatory peritoneal dialysis (CAPD) patients. There was no statistically significant association between TTV infection and age, gender, transfusion history, duration of peritoneal dialysis, AST level, ALT level, HBsAg, or anti-HCV seropositivity in peritoneal dialysis patients. Our results suggest that TTV infection is not associated with evident liver diseases, and there is no difference between TTV infection in healthy individuals and peritoneal dialysis patients. TTV transmission probably occurs via routes unrelated to peritoneal dialysis.

SEN virus co-infection among HCV-RNA-positive mothers, risk of transmission to the offspring and outcome of child infection during a 1-year follow-up

SEN is a newly discovered blood-transmissible virus. Among its variants, SENV-D and -H are most often associated with non-A, -E hepatitis. Very little is known about the risk of vertical transmission of the virus. By using polymerase chain reaction with specific primers for SENV-D and -H, we investigated the prevalence of SENV-H and -D infection, the transmission rate of SENV infection and clinical features of SENV-infected children in 89 hepatitis C virus (HCV)-positive human immunodeficiency virus type 1-negative mothers. SENV infection was found in 36 (40%) mothers, and SENV-D was more frequent than SENV-H infection (34/36, 94%vs 5/36, 14%, P < 0.01). No difference in SENV infection rates was found between injection drug user (IDU) mothers (17/51, 33%) and mothers with no risk for bloodborne infection (19/38, 50%, P = ns). SENV-H infection was found only in IDU mothers and mothers with HCV genotype1b. Both SENV-D and -H can be transmitted to the offspring with an overall rate of 47%. Vertical transmission of HCV does not facilitate SENV infection of the offspring. Among 17 SENV-infected children, none was co-infected with HCV. Maternal HCV genotype or viral load does not interfere with mother-to-infant transmission of SENV. Persistence of SENV infection was demonstrated in 100% of infected children after 1-year follow-up, but none had clinical evidence of liver disease.

Prevalence and determinants of SENV viremia among adolescents in an endemic area of chronic liver diseases

BACKGROUND

SENV is a potential causative agent responsible for chronic liver diseases (CLDs) that are precipitated in early life. SENV prevalence in adolescents is unknown and its transmission route is uncertain.

METHODS

We randomly selected 824 serum samples from a cohort of 2383 adolescents aged 15-17 years who resided in Hualien County, an endemic area of liver diseases. Serum SENV genotype-D and genotype-H DNA were assayed by seminested polymerase chain reaction.

RESULTS

The positive rates for SENV-D and SENV-H DNA were 25.1% and 30.6%, respectively. Amis adolescents had a significantly higher rate of SENV-D viremia than Han Chinese adolescents (31.0%vs 22.2%; P = 0.025). Adolescents residing in rural or mountainous areas had significantly higher rates of SENV-H viremia than those residing in urban areas. There was no difference in the positive rates of SENV-D and SENV-H DNA among adolescents with or without hepatitis B virus (HBV) or hepatitis C virus (HCV) infection or history of hospitalization, surgery or blood transfusion. In multivariate analyses, males and adolescents residing in rural or mountainous areas had significantly higher risks of SENV-H viremia. As compared with those residing in urban areas, the multivariate-adjusted odds ratio (OR) for rural and mountainous areas were 1.49 (95% confidence interval [CI], 1.08-2.07) and 2.16 (95% CI, 1.32-3.53), respectively.

CONCLUSION

SENV-D and SENV-H infection were frequent among adolescents in eastern Taiwan. SENV was unlikely to be transmitted via the parenteral route and factors associated with level of urbanization were probably the major determinants of SENV infection.

Molecular detection of transfusion transmitted virus coinfection with some hepatotropic viruses

CONTEXT

A novel human DNA virus was isolated from the serum of a patient with posttransfusion hepatitis; it was named transfusion transmitted virus (TTV).

OBJECTIVE

To ascertain the influence of TTV (detected by polymerase chain reaction amplification of a conserved region of the viral genome) coinfection in individuals infected with hepatitis viruses (A, B, and C) and to investigate the putative role played by TTV in hepatic dysfunction in individuals with acute non-A-E hepatitis.

DESIGN

Sixty-two patients with viral hepatitis were included in the study in addition to 18 blood donors. Viral study of 4 hepatotropic viruses (A, B, C, and E) was carried out. Study for TTV DNA was performed by nested polymerase chain reaction.

RESULTS

The prevalence of TTV was not statistically different between hepatitis patients and blood donors, and it was not correlated to the levels of the hepatic aspartate aminotransferase and alanine aminotransferase between individuals evidencing dual infection with hepatitis B and C viruses and healthy blood donors. However, in the group of patients with viral hepatitis of unknown etiology (non-A-E), those evidencing TTV viremia had statistically significant lower levels of alanine aminotransferase (P = .03) and aspartate aminotransferase (P = .04) than those who were TTV negative.

CONCLUSIONS

We can conclude that TTV is a frequent virus isolated from patients with various types of viral hepatitis, from cases of hepatitis without obvious viral agent, and from the healthy population. TTV has no effect on biochemical markers of associated viral hepatitis. It may be associated with a mild form of non-A-E hepatitis.

Transfusion transmitted virus in screened United Arab Emirates blood donors

OBJECTIVE

To investigate the rate of infection caused by Torque teno virus (TTV) in United Arab Emirates (UAEs) healthy population as a pilot study in detecting TTV DNA in 100 healthy blood donors.

METHODS

We randomly choose a total of 100 healthy blood donors who attended Zayed Military Hospital, Abu Dhabi, UAE from January 20 to May 30, 2005. We carried out a real-time polymerase chain reaction (PCR) test to detect TTV DNA.

RESULTS

Real-time for TTV was positive in 75 (75%) donors. Eight (73%) non-UAE donors were TTV positive while 67 (75%) were UAEs. Among these donors, 72 (77%) were males and 3 (50%) were females.

CONCLUSION

Our results demonstrated a high prevalence of TTV in UAE.

Prevalence, epidemiological aspects and clinical importance of TT virus infection in Slovakia

The aim of the study was to assess the prevalence, clinical impact and importance of different risk factors of transmission of TTV infection in Slovakia using two PCR methods. Sera of 426 adult persons were examined. TTV DNA was identified by PCR using primers from N22 and untranslated region (UTR) respectively. The established prevalence of TTV tested with N22 and UTR primers according to patients groups was: acute hepatitis of unknown etiology 4 resp. 28 of 37, acute hepatitis B 3 resp. 29 of 38, chronic hepatitis B 11 resp. 41 of 44, chronic hepatitis C 10 resp. 93 of 102, hemodialysis patients 13 resp. 72 of 72, health care workers 0 resp. 27 of 33, control group 8 resp. 83 of 100. Using N22 primers, TTV infection occurred more frequently in chronic hepatitis B group compared with health care workers, if UTR primers were used the group of hemodialysis patients differed significantly from both acute hepatitis groups, health care workers and controls (p < 0.05). From possible risk factors hemodialysis and transfusion count showed notable differences. Bilirubin and aminotransferase levels did not differ between TTV positive and negative groups. No pathogenetic role of TT virus in liver injury was confirmed.

Prevalence of transfusion-transmitted virus infection in patients on maintenance hemodialysis from New Delhi, India

Transfusion-transmitted virus (TTV) has been reported from a number of hemodialysis (HD) units from various countries throughout the world. TTV has been associated with liver diseases, viral hepatitis B, and C. Clinical details and information regarding TTV prevalence from India are insufficient. The prevalence and clinical significance of TTV infection were studied in New Delhi, India in HD patients. Serum samples were derived from 75 patients on maintenance HD, and 75 age- and sex-matched voluntary blood donors were examined for TTV viremia by nested polymerase chain reaction (PCR) using primers derived from UTR (A) region of the TTV genome. The prevalence of TTV DNA in patients on HD (83%) was significantly (p<0.05) higher than in blood donors (43%). Clinical background including the mean age, sex, mean duration of HD, and mean alanine aminotransferase (ALT) levels did not differ significantly between TTV DNA-positive and -negative HD patients. Fifty-four (72%) TTV-positive HD patients and 7 (56%) TTV-negative HD patients had blood transfusion histories (p>0.05). Among TTV-positive patients, Hepatitis B virus (HBV) co-infection was present in 14.2% cases while hepatitis C virus (HCV) co-infection was absent. Persistent elevation of ALT levels was observed in 7(9.3%) HD patients; 3 (43%) of them were TTV positive and 4 (57%) were TTV negative (p>0.05). All 3 TTV-positive patients with elevated ALT levels were co-infected with HBV. Patients with TTV infection alone showed normal ALT levels. Prevalence of TTV infection is high in North Indian patients on maintenance HD. Also, none of the exclusively TTV DNA-positive patients had clinical or biochemical signs of liver disease. TTV seems to spread through parenteral routes. More often, TTV seems to be associated with parenterally transmitted virus HBV, indicating a parenteral mode of TTV transmission. The pathogenicity of TTV remains unclear from the present study.

Presence of TT virus infection in chronic hepatitis patients from a hospital in New Delhi, India

BACKGROUND & OBJECTIVE

The recent discovery of a novel parenterally transmitted, unenveloped, single-stranded DNA virus called TT virus (TTV) in chronic hepatitis patients with unclear pathogenesis throughout the world led us to investigate, its presence in chronic hepatitis patients attending a hospital in New Delhi, India, and to evaluate its role in liver disease.

METHODS

TT virus DNA was investigated in serum samples of 70 patients with various types of chronic hepatitis, and 100 healthy subjects from New Delhi, India by nested PCR using the primers that belonged to UTR (A) region of the genome.

RESULTS

TTV DNA was detected in 6 of 23 patients (26%) with type B chronic hepatitis, 3 of 20 patients (15%) with type C chronic hepatitis, and 12 of 100 subjects (12%) from healthy control group with normal liver function profile tests. None of the 27 non-B, non-C chronic hepatitis patients had TTV DNA positivity. The prevalence of TTV was significantly higher in type-B chronic hepatitis patients as compared to normal subjects (P< 0.05) but comparable to type C chronic hepatitis patients. The clinical course and biochemical profiles of type B, or type C chronic hepatitis patients co-infected with TTV did not differ significantly from those without TTV infection.

INTERPRETATION & CONCLUSION

Interestingly, in chronic hepatitis patients, TTV was always associated with either hepatitis B or C virus indicating a likely parenteral route of transmission. All TTV-positive subjects in healthy control group showed normal clinical and biochemical profiles. Thus, the presence of TTV infection is unlikely to influence the course of chronic hepatitis related to hepatitis B virus (HBV) or hepatitis C virus (HCV) or cause liver diseases in healthy subjects.

SEN virus has an adverse effect on the survival of HIV-positive patients

BACKGROUND

Patients infected with HIV are often coinfected with other viruses.

OBJECTIVE

To investigate the effect of SEN virus (SENV) strains D and H on mortality in HIV-positive patients.

METHODS

A total of 217 HIV-positive patients were analysed retrospectively after first presentation and blood sampling (January 1997 to July 1997) and the effect of coinfection with SENV-D and SENV-H on survival was examined. Analysis periods were the time from blood sampling to the end of follow-up, and the time from diagnosis of HIV infection to the end of study follow-up. SENV-H DNA was measured quantitatively. Prevalences of SENV-D and SENV-H were compared with those in 112 healthy blood donors.

RESULTS

SENV prevalence was significantly higher in HIV-positive patients than in controls (56/217 and 12/112, respectively; P < 0.001). SENV positivity had no influence on survival, but a significant negative influence of SENV-H on survival was observed when SENV-H DNA was > 530 copies/ml, which was the mean SENV-H DNA level found in HIV-negative controls. This adverse effect was found for both studied time periods in a Kaplan-Meier analyses. A multivariate Cox regression analysis, including CD4 cell count, Centers for Disease Control and Prevention stage, age, sex, HIV RNA, highly active antiretroviral therapy and hepatitis C virus status, revealed that a high SENV DNA level was an independent risk factor or indicator for adverse disease outcome.

CONCLUSION

SENV infection is common in HIV-positive patients. High SENV-H DNA levels were predictive for poor survival in HIV-positive patients.

SEN virus: epidemiology and characteristics of a transfusion-transmitted virus

SEN virus (SEN-V) is a blood-borne, single-stranded, nonenveloped DNA virus. Although its prevalence varies by geographic region, it has been detected in as many as 30 percent of postoperative transfusion recipients, compared to 3 percent of postoperative patients who did not receive transfusions. A significant association has been observed between transfusion volume and the occurrence of SEN-V infection. Transmission by transfusion also has been confirmed by the detection of greater than 99 percent homology between SEN-V in donor and recipient sera. Concurrent infections with SEN-V and hepatitis B virus, hepatitis C virus, or human immunodeficiency virus type 1 have been documented, and these observations probably reflect the blood-borne transmission of these viruses as well as SEN-V. Although SEN-V was discovered as part of a search for causes of posttransfusion hepatitis, there is no firm evidence so far that SEN-V infection either causes hepatitis or worsens the course of coexistent liver disease. Nevertheless, SEN-V appears to be transmitted by transfusion, and further studies may reveal more about its role in the future.

Transfusion-transmitted virus is not present in factor IX concentrates commonly used to treat haemophilia B

Transfusion-transmitted virus (TTV) is a potential cause of post-transfusion hepatitis in patients with haemophilia. Plasma-derived clotting factor concentrates currently undergo processes that are effective in removal and inactivation of viruses such as HIV, hepatitis B and C; however, their effectiveness with respect to TTV is unknown. To determine if TTV DNA is present in plasma-derived concentrates of factor IX, we tested 14 lots of Mononine and compared the results with BeneFix. Nucleic acid isolation, followed by a two-round polymerase chain reaction (PCR) and agarose gel analysis indicated that all 17 lots were negative for TTV. Although TTV may be considered an emerging pathogen, no evidence of the virus was detected in the commercially available plasma-derived concentrate of FIX most commonly used to treat haemophilia B.

TT virus among blood donors in Alexandria

TTV is a non enveloped, single-stranded, circular- DNA virus that has been assigned to the Family Circiniviridae. The primary mode of TTV transmission was proposed to be transfusion (and hence its name). Little is known about the clinical significance and the natural history of TTV infection. Hence, responsibility of the virus for specific liver disease is still debated. In our study, we tested ninety five blood donors attending Kom EL-Decka regional blood bank in Alexandria for the presence of TTV DNA in their sera by PCR technique. The same samples were tested for ALT and AST levels by colorimetric technique and for HBsAg and anti-HCV by the ELISA technique. Out of the 95 blood donors, 46 (48.4%) had TTV DNA in their sera. None of the 95 blood donors included in this study was positive for HBsAg, while 22 (23.2%) were anti-HCV positive. Out of the 22 anti-HCV positive blood donors, 13 (59.1%) were TTV DNA positive, while out of the 73 anti-HCV negative blood donors, 33 (45.2%) had TTV DNA in their sera. There was no statistically significant difference between the prevalence of TTV DNA and anti-HCV in blood donors. No biochemical evidence of liver disease potentially linked to the TTV infection was observed in our blood donors who were TTV DNA positive. Furthermore, the occurrence of elevated serum AST and ALT was most often linked to HCV rather than TTV.

Co-infections with hepatitis G and TT virus in patients with chronic hepatitis C in Hungary

The significance of co-infections with novel hepatitis viruses Hepatitis G (GBV-C, HGV) and TT virus (TTV) in chronic hepatitis C is not clear. We determined the prevalence of HGV RNA and TTV DNA in chronic hepatitis C patients and in asymptomatic hepatitis C virus (HCV) carriers, and assessed the influence of these agents on the course of HCV infection. Seventy-seven patients with chronic hepatitis C--50 of them treated with interferon (IFN)--and 33 HCV carriers with normal alanine aminotransferase have been investigated. Previous HBV infection was detected by testing serum HBsAg and aHBc. HGV RNA and TTV DNA were detected by PCR. In the healthy population, the prevalence of anti-HCV was 0.3%, HGV RNA 8.0% and TTV DNA 18.5%. In chronic hepatitis C HGV RNA occurred in 9.09% and TTV DNA in 40.25% of cases. In IFN-treated patients with sustained remission, the frequency of TTV was 20% vs. 45.7% found in non-responders. Among asymptomatic HCV-carriers, the prevalence of HGV RNA was 9.09% and TTV DNA 75.7%. Neither HGV RNA nor TTV DNA had apparent effect on the HCV infection. TTV was detected with the lowest frequency in persons with sustained remission due to IFN, suggesting antiviral effect of IFN on TTV.

TT virus infection in acute and chronic liver diseases and in patients regularly receiving blood products in Belgium

BACKGROUND

TT viruses are single-stranded DNA viruses, suggested to be involved in non A-E hepatitis. We studied the prevalence of TTV infection in acute or chronic hepatitis in Belgium in comparison with that in blood donors and in patients regularly receiving blood products.

METHODS

TTV-DNA was detected by PCR using the primer set of Takahashi et al (1998) or a nested-PCR specific for genotype-2, because it had been reported that this subtype might be more pathogenic (Tagger et al. 1999).

RESULTS

TTV-DNA was present in 49% of 128 patients with chronic hepatitis C, in 54% of 54 with chronic hepatitis B and in 54% of 24 with acute liver failure. This prevalence is similar to the 47% in 127 patients with clotting disorders, or the 64% in 103 undergoing chronic haemodialysis, but lower than the 29.7% found in 340 healthy blood donors. Significant differences in clinical or biochemical characteristics between TTV- positive or TTV-negative patients could not be substantiated. The genotype-2 subgroup comprised 3.9%, but they also did not differ from non genotype-2 patients.

CONCLUSIONS

The prevalence of TTV infection was higher in patients than in healthy blood donors. Its clinical significance remains questionable since clinical and biochemical characteristics were not different between TTV positive and TTV negative patients. The higher prevalence of TTV in patients might be related to parenteral transmission, but the relatively high prevalence in healthy blood donors points to an additional presumably faeco-oral infection. The presence of TTV in animals suggests that infection might also originate from food. Long term follow-up will have to define whether co-infection with TTV eventually alters the natural history of chronic hepatitis.

Response of TT virus to IFN plus ribavirin treatment in patients with chronic hepatitis C

AIM: TT virus (TTV) is a newly described DNA virus related to postransfusion hepatitis that produces persistent viremia in the absence of clinical manifestations. PEG-IFN plus ribavirin have been useful in the treatment of chronic hepatitis C infection. This study investigated the responses of TT virus (TTV) and hepatitis C virus (HCV) to PEG-IFN plus ribavirin therapy.

METHODS: Fifteen patients infected with HCV were treated with PEG-IFN(0.5 μg/body weight/week) and ribavirin (1000 mg-1200 mg/daily) for 48 weeks. Blood samples were drawn at the beginning and the end of the therapy. Serum TTV DNA and HCV RNA were quantified by real time PCR.

RESULTS: At the beginning of treatment, TTV infection was detected in 10/15 (66.6%) of HCV-infected patients. Loss of serum TTV DNA at the end of therapy occurred in 6/10 (60%) patients. Out of these 6 patients, 4 (67%) became positive for TTV DNA after 6 months of therapy. Regarding HCV viremia, 11/15 (73%) patients were negative for serum HCV RNA after 48 weeks of therapy, 7/11 (64%) of these cases also became negative for TTV DNA following the combined treatment. In the 3/4 (75%) patients who were positive for HCV RNA at the end of therapy, TTV DNA was detected as well. Sustained HCV response at 6 months after treatment was 53% (8/15).

CONCLUSION: No TTV sustained response can be achieved in any patient after PEG-IFN plus ribavirin administration.

TT virus-positive hepatocellular carcinoma arising from non-cirrhotic liver in an elderly man

A 43-mm hepatic tumor was incidentally detected by computed tomography in a 72-year-old man. Liver function test results were normal. Serum hepatitis B, C and G viruses were negative, while serum TT virus was positive. Autoantibodies were negative. The patient had no history of alcohol consumption. The tumor was found to be a moderately differentiated hepatocellular carcinoma (HCC) from a resected specimen. Neither lobular inflammation nor fibrosis was observed in the surrounding liver. Intrahepatic hepatitis B virus was not detected. This is a case of non-B, non-C HCC positive for only TT virus arising from a non-cirrhotic liver.

Prevalence of transfusion transmitted virus infection and its effect on renal graft survival in renal transplant recipients

OBJECTIVE

Little is known about the prevalence of transfusion transmitted virus (TTV) infection in renal transplant recipients (RTxs) and its effects on allograft survival. We investigated the prevalence of TTV and its effects on liver injury and graft survival in RTxs.

MATERIAL AND METHODS

The study was performed in 33 consecutive RTxs (8 females, 25 males) and 100 blood donors (35 females, 65 males). A nested polymerase chain reaction was used to detect TTV DNA in serum. Serum creatinine and alanine aminotransferase (ALT) levels and 24-h protein excretion were determined in both TTV-positive and-negative patients. The total number of blood transfusions, the duration of hemodialysis and the total duration after transplantation were recorded in RTxs. In addition, hepatitis B surface antigen (HbsAg), anti-hepatitis C virus (HCV) and hepatitis G virus DNA antibodies were determined in all patients.

RESULTS

TTV DNA was detected in 51.5% of RTxs and in 7% of the control group and this difference was statistically significant (p < 0.01). In the RTx group, 64.7% of TTV-positive and 56.2% of TTV-negative patients had undergone a previous blood transfusion. However, the blood transfusion replacement rate, total duration of dialysis therapy and posttransplant period did not differ between these two groups. Five (15.1%) patients in the RTx group had abnormal liver function tests (ALT >40 IU/l). Of these patients, 2 were anti-HCV-positive, 1 was HBsAg-positive and anti-HCV- plus TTV DNA-positive and the serologic tests of the remaining 2 patients were all negative. Among the TTV-positive patients, 2 (11.7%) were anti-HCV-positive, 1 (5.8%) was HBsAg-positive and 3 (17.6%) were HGV DNA-positive. The baseline serum creatinine levels did not differ significantly between the TTV-positive and-negative patients, being 1.5 +/- 0.6 and 1.4 +/- 0.6 mg/dl, respectively ( p > 0.05). Two of the TTV-positive patients and 1 of the TTV-negative patients had proteinuria. A 1-year follow-up of TTV-positive and-negative patients demonstrated neither acute nor chronic graft rejection.

CONCLUSION

In RTxs, TTV infection was more prevalent than in the normal population. In our patients the virus did not have an important effect on renal graft rejection and did not cause liver injury. However, the question of whether TTV infection may affect graft survival requires further long-term investigation in larger groups.

No effect of transfusion transmitted virus viremia on the distribution and activation of peripheral lymphocytes in hemodialyzed patients

AIM

We aimed to examine the distribution and activation of peripheral T cells in TTV positive (n = 32) and negative (n = 17) hemodialyzed patients. The control group (n = 20) consisted of healthy blood donors.

METHOD

TTV-DNA was detected by seminested PCR. CD3, CD4, CD8, CD19, CD56, CD3/HLA-DR, CD3/CD69 and the Th1/Th2 ratio of T cells were analyzed by flow cytometry. Circulating IFN-gamma, IL-2, IL-4, IL-6, IL-10, IL-13, TNF-alpha, TGF-beta levels were measured by ELISA in the sera.

RESULTS

There was no difference between the CD3, CD4, CD8 and CD19 values of HD subjects. In addition, the expression of both activation markers, HLA-DR and CD69, was significantly elevated in the TTV-positive and -negative HD groups compared to the controls, but not showing any difference from each other. The measurements of intracellular cytokines showed the enhanced occurrence of INF-gamma + CD4 T cells, and decreased appearance of IL-4 + CD4 lymphocytes in the HD groups without any significant difference between the TTV virus positive and negative patients. In addition, HD also elevated the expression of IL-10 in CD4 and CD8 (Th2) cells. There were only two significant changes in the levels of circulating cytokines: (a) IL-2 increased; (b) IL-13 decreased in both groups of HD patients compared to the controls, independently of TTV positivity or negativity.

CONCLUSIONS

We assume that transfusion-transmitted virus does not cause any specific change in the distribution and activation of lymphocytes in the peripheral blood of hemodialyzed patients. Hemodialysis itself, however, results in a significant activation of peripheral T cells with the domination of increased production of Th1 type cytokines, IFN-gamma, IL-2, in contrast to the decreased synthesis of Th2 type cytokines, IL-4 and IL-13. Furthermore, the increased expression of IL-10 in the CD4 and CD8 cells of HD patients can be the sign of a contraregulatory Th2 activation as an answer on the Th1 effect.

Investigation of TT virus in the etiology of pediatric acute lymphoblastic leukemia

Infectious agents have been implicated in the pathogenesis of pediatric acute lymphoblastic leukemia (ALL). A novel human DNA virus, TT virus (TTV), has been identified in children possessing characteristics as an etiologic agent, making the virus a potential candidate. Analysis of specimens from children with ALL was performed to determine if an association exists. Archived specimens (79 peripheral blood mononuclear cells, PBMC/bone marrow cells, BMC, and 125 cerebrospinal fluid, CSF) obtained at diagnosis and during therapy from 28 pediatric patients were tested for TTV. All of the diagnostic BMC/PBMC were negative for TTV, but 7 patients had follow-up specimens that converted to TTV positivity. TTV was not detected in any CSF. The absence of TTV at diagnosis suggests TTV is unlikely to be causally associated with ALL in the cases analyzed. However, the data support TTV transmission through blood products and suggest that the CNS is not a sanctuary site for TTV.

New prevalence estimate of TT virus (TTV) infection in low- and high-risk population from São Paulo, Brazil

The prevalence of TT virus (TTV) infection was investigated by Polymerase Chain Reaction (PCR) in low- (blood donors and healthy children/adolescents) and high-risk (hemophiliacs) groups from São Paulo, Brazil. Primers based on the untranslated region (UTR) of the viral genome proved to be much more ubiquitous, leading to much higher frequencies for both groups (>or= 81%) than the earlier N22-PCR directed to the open reading frame 1 (blood donors, 5.5%, and hemophiliacs, 42.3%). The UTR-PCR also revealed an interesting profile for healthy children/adolescents: very high prevalence at the early years and significant decrease in male teenagers. The N22-PCR, in turn, demonstrated higher frequency in hemophiliacs treated with fresh blood products (58%), than in those treated with virus-inactivated clotting factors (9.4%) and blood donors (5.5%).

Investigation of transfusion transmitted viruses in cases clinically suspected of posttransfusion hepatitis with undetermined ethiology

Transfusion transmitted viruses (TTV) were investigated in cardiac surgery cases who were previously transfused with blood and/or blood products and were suspected of having posttransfusion hepatitis (PTH) based on the results of physical examination, clinical findings, biochemical blood test results and in a smaller number, on radiological results. They were identified as having non-A-C hepatitis based on serological or molecular test methods. In this study, out of 90 cases suspected for PTH and non-A-C, 78 (86.7%) were male, 12 (13.3%) were female and their ages were between 17 and 67. Ninety healthy blood donors, who donated blood for the first time and had never had a transfusion, were selected as the control group. They had alanine aminotransferase (ALT) levels < 40 U, were seronegative for hepatitis B virus (HBV) and hepatitis C virus (HCV). Seventy-seven were immune, and 13 were seronegative for hepatitis A virus (HAV). In this study, TTV-deoxyribonucleic acid (DNA) investigation was performed by the polymerase chain reaction (PCR) method suggested by Takahashi et al. with 5' GCT ACG TCA CTA ACC ACG TG 3' (T801) and 5' CTG CGG TGT GTA AAC TCA CC 3' (T935) primers. TTV-DNA was found to be positive in 21 (23.3%) of the patient group and 4 (4.4%) of the control group (p < 0.05). In the patients determined to be TTV-DNA positive, the admission time following transfusion was a minimum of 3, and a maximum of 15 (average 7) weeks. The average ALT levels detected at the time of admission did not show a difference between TTV-DNA positive and negative cases (p > 0.05). However the ALT levels had a tendency to rise and reached their highest level nine weeks after transfusion in the TTV-DNA positive cases, although in two cases the ALT levels decreased to normal value after the 13th week. During the 24 month follow up of the TTV-DNA positives all cases except one were positive at the end of this period. The results of this study are the same as those reported in the literature suggesting that TTV-DNA, excluding the main viral agents which are known to cause PTH, can be determined in transfused PTH or non-transfused asymptomatic patients in varying ratios. In order to define the epidemiological properties and hepatic-extrahepatic pathologies more clearly we have looked for evidence of the viral agent, which probably contaminates both by transfusion and non-transfusion routes. It is suggested that, in addition to the case groups in this study, new clinical studies are necessary including transfused but non-PTH patients.

Prevalence of TT virus in a CAPD population

TT virus (TTV) has recently been identified in patients with post-transfusion non-A, non-G hepatitis. It is reported to be common in patients with a variety of liver diseases and with history of transfusion. Its pathogenesis in chronic liver diseases remains unclear. In this study, we have determined the prevalence of TTV in a continuous ambulatory peritoneal dialysis (CAPD) population and related its prevalence with history of previous hemodialysis, transfusion, HCV positivity and serum alanine amino-transferase (ALT) levels. TTV was detected in 44% of 63 CAPD patients and 30% of 43 healthy controls (p = 0.15). Frequency of TTV was similar in previously hemodialysed and never hemodialysed (8/14, 57% vs. 20/40, 41%, p = 0.15) and previously transfused and non-transfused (7/19, 37% vs. 15/44, 34%) CAPD patients. Prevalence of TTV was also similar in HCV(+) and HCV(-) patients. Serum ALT levels were 19 +/- 16 and 20 +/- 12 U/l in TTV(+) and TTV(-) patients, respectively. These results indicate that prevalence of TTV in a CAPD population is similar to healthy controls, and other routes of transmission in addition to parenteral routes might be involved in the transmission of TTV.

Coinfection of TT virus and response to interferon therapy in patients with chronic hepatitis B or C

AIM

To investigate the serum positive percentage of TT virus (TTV) in patients with chronic hepatitis B or C and the response of the coinfected TTV to interferon (IFN) during IFN therapy for chronic hepatitis B and C.

METHODS

We retrospectively studied the serum samples of 70 patients with chronic hepatitis who had received IFN-alpha therapy from January 1997 to June 2000, which included 40 cases of hepatitis B and 30 hepatitis C. All the patients had been followed up for at least 6 months after the end of IFN therapy. The serum TTV DNA was detected using the polymerase chain reaction (PCR) before and every month during the course of IFN treatment.

RESULTS

TTV infection was detected in 15% (6/40) of the chronic hepatitis B group and 30% (9/30) of the chronic hepatitis C group. Loss of serum TTV DNA during IFN therapy occurred in 3 of 6 patients (50%) and 6 of 9 (67%) of hepatitis B and C groups, respectively. Seronegativity of TTV was found all during the first month of IFN therapy in the 9 patients. There was no correlation between the seroconversion of TTV and the biochemical changes of the patients.

CONCLUSION

TTV is not infrequently coinfected in patients with chronic hepatitis B and C in Taiwan, and more than half of the TTV infections are IFN-sensitive. However, the loss of serum TTV DNA does not affect the clinical course of the patients with chronic hepatitis B or C.

Infectious hepatitis C, hepatitis G, and TT virus: review and implications for dentists

In the past 10 years, hepatitis C and G viruses have been identified, and in the last two years a further parenterally transmitted agent, termed TT virus (TTV), has been discovered. These viruses have a worldwide distribution and frequently cause chronic infection. The purpose of this article was to promote an understanding of these viral agents and their relevance in dental practice. Infected patients may develop a chronic carrier state without clinical disease or may develop liver disease, and may have related oral conditions. Dental providers will see a growing number of patients with HCV/HGV and possibly TTV infection. All of these patients require appropriate infection control measures during dental treatment.

[Relationship between TT virus infection and hepatocellular carcinoma]

OBJECTIVE

To clarify the relationship between TT virus (TTV) infection and the development of hepatocellular carcinoma (HCC).

METHODS

TTV was examined in sera of 112 patients with HCC and 95 patients with chronic liver disease (CLD) without HCC. 30 patients without liver disease were examined as control. TTV DNA was detected by the second generation of TTV PCR primers (NG059, NG061 and NG063) after extraction of DNA from 50 microliters serum. The relationship between TTV infection and clinical features of each group patients was analyzed.

RESULTS

TTV DNA was detected in 17.86% (20/112) of HCC patients, and this prevalence in HCC patients was not significantly higher than that of TTV DNA in CLD patients (15.78%, 15/95). There were no significant differences in age, gender, tumor factors (size, TNM classification and markers) and other hepatitis virus markers between TTV-positive and TTV-negative in HCC and CLD patients, except history of blood transfusion [(80.00% vs 35.87% (P < 0.05) in HCC patients and 73.33% vs 27.50% (P < 0.05) in CLD patients)] and ALT [(93 +/- 27) IU/L vs (68 +/- 31) IU/L (P < 0.05) in HCC patients]. It seemed that TTV did not do any harm to the liver function of patients who infected with HBV or HCV, except for elevating ALT level in such a kind of HCC patients.

CONCLUSION

Although TTV could do harm to the liver function of HCC patients, it does not contribute to the development of HCC from CLD.