Biliary excretion of TT virus (TTV)

A novel DNA virus (TT virus; TTV) was isolated from a patient with post-transfusion hepatitis of unknown etiology. If TTV replicates in the liver, TTV may appear in the bile. In the present study, to clarify whether fecal-oral infection occur via biliary excretion, the presence of TTV DNA was assessed in paired serum and bile samples collected from 28 patients with obstructive jaundice without parenchymal liver disease. TTV DNA was detected by polymerase chain reaction (PCR) using semi-nested primers, and quantified by Real Time Detection PCR (RTD-PCR). The nucleotide sequence of isolates TTV DNAs was also determined and the sequences were compared between serum and bile samples. Among 28 patients, 7 were positive for TTV DNA in both samples, and 3 and 2 were positive in serum and bile respectively. Of 7 patients positive for TTV DNA in both samples, the TTV DNA titer was higher in serum of 4 patients and in bile of 1 patient. Among 7 patients positive for TTV DNA in serum and bile, 6 had the same sequence in both samples. Multiple distinct types of TTV DNA clones were isolated from serum in 2 patients and from bile in 4 patients. In conclusion, TTV DNA is detected frequently in bile from patients with obstructive jaundice, suggesting a fecal-oral route of infection and high prevalence of asymptomatic TTV carriers. TTV DNA was detected only in serum from some patients, suggesting that replication of TTV may occur in other organs as well as in the liver.     

GB virus C/hepatitis G virus and TT virus infections among high risk renal transplant recipients in India.

BACKGROUND: GB virus C/hepatitis G virus (GBV-C/HGV) and TT virus (TTV) have been widely reported in patients with high parenteral risk such as haemodialysis and renal transplant recipients. The occurrence of these agents in association with hepatitis B virus (HBV) and hepatitis C virus (HCV), in Indian renal transplant recipients, is yet unreported. STUDY DESIGN: Molecular and serological markers of GBV-C/HGV and TTV were examined in addition to those for HBV, HCV and hepatitis D virus (HDV) in a selected group of seventy renal transplant recipients. HGV RNA detection was achieved using primers specific for the 5'NCR and NS5a regions of the genome. Anti-GBV-C/HGV antibody was detected using the mu plate anti-HG env kit (Roche, Germany). TTV DNA PCR was performed using primers specific for the coding region (method A) of the genome. In 50% of patients, TTV DNA was also tested for using primers specific for the non-coding region (method B). Host related factors such as age, alanine aminotransferase (ALT) levels, number of transfusions, haemodialysis sessions, and months following transplantation were also studied. RESULTS: Exposure rates to GBV-C/HGV, TTV (method A), HBV, HCV and HDV were 58.6, 32.9, 52.9, 54.3 and 2.9%, respectively. 'Active' infection as measured by viraemia and/or virus-specific antigenaemia for GBV-C/HGV, TTV, HBV and HCV was 52.9, 32.9, 15.7 and 52.9%, respectively. The majority of GBV-C/HGV and TTV infections were seen as co-infections with other hepatitis viruses. Single infection with GBV-C/HGV and TTV was seen in ten (14.2%) and eight (11.4%) patients, and was not associated with ALT elevation when compared to uninfected blood donors. Using univariate analysis, GBV-C/HGV RNA was significantly associated with > or =20 haemodialysis sessions. TTV DNA occurrence was not associated with any risk factors. CONCLUSIONS: There is a high occurrence of GBV-C/HGV and TTV in this select group of renal transplant recipients in India. These viruses mostly occurred in the context of co-infections with other hepatitis viruses. Long term effects of multiple hepatotropic viral infections need to be carefully documented in such transplant populations.     

High prevalence of TT virus (TTV) and TTV-like minivirus in cervical swabs

Genomes of TT virus (TTV) and TTV-like minivirus DNA were detected in 80% and 61% of cervical swabs from healthy women, respectively, regardless of concurrent human papillomavirus infection. These results show that the potential exists for sexual transmission of TTV and related viruses.     

Effect of immune modulation on TT virus (TTV) and TTV-like-mini-virus (TLMV) viremia

The present study was designed to investigate how two chronically replicating viruses, TT virus (TTV) and TTV-like mini virus (TLMV), interact with host defence systems. Successive serum samples from three groups of subjects, undergoing modifications of their antiviral defence, were tested by real-time PCR to measure changes in viral titers, and by sequence analyses to indicate whether increases in viremia could be attributed to infection with an unfamiliar strain: 1) in patients receiving immunosuppressants subsequent to kidney transplantation, viral titers tended to increase; 2) in soldiers undergoing extreme training known to cause immunosuppression, insignificant increases in titers were observed; and 3) interferon treatment of patients with hepatitis C virus caused a temporary decrease in TTV and TLMV titers. Increases in viremia were associated only occasionally with the appearance of novel strains. The above results add to knowledge on how these viruses are influenced by the host.     

TT virus (TTV) genotyping in blood donors and multiple transfused patients in Brazil

TT virus (TTV) is widely distributed in the general population. The objective of the present study was to investigate the prevalence and distribution of TTV genotypes among blood donor candidates and multiple transfused patients in the Southeast region of the state of São Paulo, Brazil. TTV-DNA detection by amplification of a segment of the ORF-1 region, presented a prevalence of 11.9% in 270 serum samples from blood donors, of 46.2% in 18 samples from patients with coagulopathies, and of 31.8% in 15 samples from patients with hemoglobinopathies. When specific primers for the non-coding (UTR) region of the TTV genome were used the prevalences were 50.5%, 95.0%, and 82.0% for blood donors, patients with coagulopathies and patients with hemoglobinopathies, respectively. Positive samples from 49 individuals were sequenced and partial segments of 230 base pairs referring to the ORF-1 region of the TTV genome were used for the determination of their genotypes with the aid of phylogenetic analysis. The most frequent genotype was 1 (74.0%), followed by genotype 2 (26.0%). These data indicate a high prevalence of this virus in the populations of blood donors and transfused patients, providing further evidence for the role of transfusions as an efficient pathway in the transmission chain.     

A new genotype of TT virus (TTV) infection among Colombian native Indians

Serum TTV DNA was assayed in 140 native Indians and 40 members of the general population in Colombia to determine the prevalence of TT virus (TTV) infection among Colombian native Indians. Of the 140 native Indians, 23 (16.4%) were positive for TTV DNA, compared to 4 (10.0%) of 40 from the general population (P = not significant). The prevalence of TTV DNA among native Indians was much higher than that of HBsAg and anti-HCV. Comparison of subjects with and without TTV DNA revealed no significant differences in all characteristics between the two groups. A phylogenetic tree, using the open reading frame 1 sequence (222 bp), indicated that the virus could be classified into four different genotypes, including three previously reported ones. The results show that TTV infection is common in Colombian native Indians without liver disease and also indicate the existence of a novel genotype of TTV.     

The prevalence of TT virus (TTV) infection and its relationship to hepatitis in children

TT virus (TTV) is a newly discovered virus from a patient with post-transfusion hepatitis. We investigated the frequency and pathogenesis of TTV infection in children. A semi-nested PCR assay was used to amplify TTV-DNA in serum samples from 254 ambulatory children without liver disease, 20 with hepatitis of unknown etiology, and 18 transfusion recipients or hemophiliacs. In positive samples, TTV-DNA was quantified by real-time quantitative PCR using a fluorescent probe. We detected TTV-DNA in 20% of children with hepatitis of unknown etiology, which was not statistically different from the 23% prevalence in ambulatory children. In transfusion recipients or hemophiliacs, the frequency was higher (50%) than that in ambulatory children (P = 0.01). Among ambulatory children, TTV-DNA was frequently detected in children with acute gastroenteritis (36%). TTV-DNA was detected in 10% of the infants under 6 months old, and 20% of the children from 7 to 12  months old. The prevalence was constant after the age of 1 year; however, the copy number of TTV-DNA was significantly higher in children under 1 year of age (mean: 10^5.4 versus 10^3.8 copies/ml, P= 0.008). Finally, TTV-DNA was quantified serially in three children with chronic hepatitis who were positive for TTV-DNA. The presence or amount of TTV-DNA was unrelated to the serum alanine aminotransferase level. These results indicate that TTV infection is common in children. The larger quantity of TTV-DNA in infants and the high prevalence of TTV in children of all ages suggest that TTV may be transmitted in early childhood. Its relationship to hepatitis is doubtful in children. Received: 8 April 1999     

B19 virus infection in renal transplant recipients.

BACKGROUND: B19 virus infection with persistent anaemia has been reported in organ transplant recipients. Detection of B19 virus DNA in serum is the best direct marker of active infection. OBJECTIVE: The present study evaluated the incidence and clinical role of active B19 virus infection in renal transplant recipients presenting with anaemia. STUDY DESIGN: Forty-eight such recipients were investigated by nested PCR on serum samples. The controls were 21 recipients without anaemia. Active HCMV infection was also investigated as a marker of high immunosuppression. RESULTS AND CONCLUSIONS: In 11/48 (23%) patients B19 virus DNA was demonstrated in serum versus only 1/21 (5%) of the controls. Ten of these 11 patients had already been seropositive at transplantation and active infection occurred in eight of them during the first 3 months after transplantation. The remaining patient experienced a primary infection 9 months after transplantation. Eight (73%) of these 11 patients displayed a concomitant HCMV infection and four (36%) showed increasing serum creatinine levels but none developed glomerulopathy; 3/11 (27%) recovered spontaneously from anaemia whereas 8/11 (73%) needed therapy. In conclusion, the relatively high occurrence (23%) of B19 virus infection in patients presenting with anaemia, suggests that it should be considered in the differential diagnosis of persistent anaemia in renal transplant recipients. Presence of the viral DNA should be assessed early from transplantation and the viral load should be monitored to follow persistent infection and better understand the relation between active infection and occurrence of anaemia, and to assess the efficacy of IVIG therapy and/or immunosuppression reduction in clearing the virus.     

TT virus (TTV) loads associated with different peripheral blood cell types and evidence for TTV replication in activated mononuclear cells

TT virus (TTV) loads associated with the peripheral blood cells of seven patients known to carry the virus in plasma were investigated by real-time PCR. Whereas red cells/platelets were uniformly negative, six and four patients yielded positive peripheral blood mononuclear cells (PBMCs) and polymorphonuclear leukocytes, respectively, but viral titres were generally low. Fractionation of PBMCs into monocyte- and B, T4, and T8 lymphocyte-enriched subpopulations showed no pattern in the viral loads that might suggest the preferential association of TTV to one or more specific cell types. TTV-negative PBMCs absorbed measurable amounts of virus when incubated with infected plasma at 4 degrees C. Furthermore, cultures of TTV-negative phytohaemagglutinin-stimulated PBMCs exposed in vitro to virus-positive plasma and faecal extracts released considerable levels of infectious TTV into the supernatant fluid and the same was true for TTV-positive stimulated PBMCs. These results indicate that, whereas freshly harvested resting PBMCs seem to produce little, if any TTV, stimulated PBMCs actively replicate the virus.     

Detection of TT virus DNA in patients with liver disease and recipients of liver transplant

TT virus (TTV) is transfusion-transmissible but its involvement in post-transfusion hepatitis is uncertain. To investigate the potential association of TTV with liver diseases, the prevalence of TTV DNA was tested by semi-nested PCR in 113 carriers of hepatitis C virus (HCV), 10 patients with acute liver failure, 11 patients with cryptogenic cirrhosis and 200 control blood donors. Thirty-seven of these patients underwent liver transplantation and were tested pre- and post-transplantation. TTV DNA was semi-quantified in serial samples from seven patients with unexplained post-transplant hepatitis. TTV genotyping was performed on samples from 28 patients by sequence analysis. The prevalence of TTV DNA in blood donors was 1.5% and 17% in HCV infected haemophiliacs. In patients with acute or chronic liver disease or hepatitis, 6 to 27% prevalence was observed. After liver transplantation, the prevalence of TTV DNA increased from 16 to 46% (P < 0.01). In patients who developed unexplained hepatitis post-transplantation, TTV viraemia did not parallel ALT levels. TTV DNA either increased in titre or became detectable shortly after transplantation, suggesting that either TTV was transfusion-transmitted, or, more likely, that immunosuppression caused a recurrence of low level or undetectable TTV viraemia. TTV had considerable genomic diversity in the N22 region, corresponding to at least 4 genotypes. Genotype 2 was found in 14/28 patients.     

Apoptosis and hepatitis C virus infection in renal transplant recipients

Hepatocellular injury in renal transplant recipients with hepatitis C virus (HCV) infection remains unclear. The suppressed immune response, in combination with increased viremia levels, provides a unique setting for the study of a potential HCV-induced apoptotic process.Liver biopsy specimens from 59 HCV-infected renal transplant recipients were examined histologically. DNA fragmentation was detected by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-nick end labeling assay, and the CD8 T-cell count was assessed immunohistochemically.A low apoptotic index (0-2.5) was observed in 31 cases, a moderate index (2.6-5) in 16, and a high index (>5) in 12. Apoptotic cell death correlated significantly with viremia because it was demonstrated by higher HCV-RNA levels in cases with a high number of apoptotic cells (odds ratio, 2.96; 95% confidence interval, 1.0-8.5; P = .04). No correlation was found between the apoptotic index and hepatitis necroinflammatory activity, CD8 cell count, fibrosis stage, immunosuppressive therapy, or genotype.In HCV-infected renal transplant recipients, apoptotic cell death seems to be associated with high viral load, thus providing indications of viral interference in the pathogenetic process.     

The entire nucleotide sequences of two distinct TT virus (TTV) isolates (TJN01 and TJN02) remotely related to the original TTV isolates

Summary.  TT virus (TTV) has a wide range of sequence divergence by which it is classified into at least 16 genotypes. A TTV isolate of genotype 12 (TJN01) and another of genotype 13 (TJN02) were sequenced in the entire genome, and compared with the reported TTV isolates. TJN01 and TJN02 had genomic lengths of 3787 and 3794 nucleotides (nt), respectively, which were shorter by 66 and 59 nt than the prototype TTV isolate of genotype 1 (TA278). TJN01 and TJN02 shared the nucleotide sequence with TA278 merely in 53.9% and 55.2%, respectively. They possessed two major open reading frames (ORFs) and the noncoding region with a GC-rich region forming stem-loop structures, which are characteristic of TTV. However, their amino acid sequences in ORF1 were similar to that of TA278 in only 35.4 and 34.0%, respectively; TJN01 was 45.4% similar to TJN02. Comparison with TTV isolates of the same genotype identified hypervariable regions in ORF1 of TJN01 and TJN02, as in the prototype TTV of genotype 1. However, quasispecies were barely observed in them. Furthermore, sequences of hypervariable regions scarcely changed during 2–5.5 years in both TJN01 and TJN02. These results indicate that TTV of genotypes 12 and 13 are much different from the prototype TTV of genotype 1. Received January 24, 2000 Accepted March 22, 2000     

中国和日本部分地区TT病毒的检出率及基因亚型 …

目的 比较中国及日本部分地区ＴＴ病毒（ＴＴＶ）感染情况及基因亚型分布特征。方法 采用半巢式－聚合酶链反应（Ｓｅｍｉ－ｎｅｓｔｅｄ ＰＣＲ）检测中国和日本部分慢性丙型肝炎患者及正常人血标本中的ＴＴＶ感染情况,并对阳性产物片段直接进行序列分析。结果 发现中国部分正常人群ＴＴＶ感染率为６４％;慢性丙型肝炎患者ＴＴＶ感染率中国国为６８％,日本为４９．１％,基因亚型分布中国ＴＴＶ Ｇ２ａ＋２ｂ亚型占６０％,     

Genotypic distribution of TT virus (TTV) in a Czech population: evidence for sexual transmission of the virus.

BACKGROUND: TTV is a new DNA virus distinguished by its high degree of strain heterogeneity. The geographic clustering of viral genotypes suggests frequent community transmission. While no specific human disease has yet been linked to it, a transmission mechanism that facilitates strain diversity may eventually select for a strain that will become pathogenic. OBJECTIVE: This study was performed to examine the prevalence, genotypic distribution, and mode of transmission of TTV in detail. STUDY DESIGN: Three groups of study subjects were recruited between October 1998 and January 2000 in Prague, Czech Republic. Group 1 included 152 injection drug users with liver disease; group 2 included 102 persons with liver disease who denied ever using injection drugs; group 3 included 111 prospective blood donors. TTV DNA was detected from blood by a semi-nested PCR assay, and a selected set of PCR products was genotyped by direct sequencing. Factors associated with TTV prevalence in groups 1 and 2 subjects were compared. RESULTS: TTV was detected in 15.8, 13.7, and 13.5% of Groups 1, 2, and 3 subjects, respectively (P>0.05). The most common genotype was 2 (54%), followed by 1 (13%). The prevalence of TTV viremia was nearly three times higher in persons with a present or past history of hepatitis B compared to those without (P<0.05). TTV prevalence increased proportionately with the number of lifetime sex partners in both groups (P<0.05); it was highest (32%) among non-users of injection drugs who had five or more lifetime sex partners. CONCLUSION: TTV prevalence in the Czech population is similar among blood donors, persons with liver disease, as well as in a high-risk population of injection drug users. TTV appears to be sexually transmitted.     

Detection of TT DNA virus (TTV) in blood donors and patients with hepatitis of unclear etiology]

A new human infective agent: TT virus (TTV) has been recently identified. The polymerase chain reaction detected TTV DNA in the sera of 5 (31.3%) out of 16 children with acute hepatitis, 5 (17.2%) out of 29 children and 3 (14.3%) out of 21 adults with liver diseases of unknown etiology, and 18 (13.2%) out of 136 free-of-charge blood donors. These results indicate a high prevalence of TTV infection in Russia and absence of an obvious correlation between this infection and nonA, nonB, nonC hepatitis in examined patients. Phylogenetic analysis of amplified fragments of viral DNA from 3 patients selected at random showed that the isolated strains belong to subtype 1a, most prevalent in the world.     

Cytomegalovirus infection in renal transplant recipients

Cytomegalovirus (CMV) belongs to the family of human herpes viruses. It is also known as the human herpes virus 5 (HHV-5). In immunocompromised host it becomes significant pathogen, causing the spectrum of different symptoms and affecting different tissues and organs. Epidemiologic forms of CMV infection include primary infection, reactivation or secondary infection, and superinfection or reinfection. CMV infection has direct and indirect effects. Direct effects occur at the time of highest viraemia with severe clinical presentation. To the contrast, indirect effects occur at the time of asymptomatic viraemia as the consequence of immunologic response. Indirect effects are mediated by cytokines, chemokines and growth factors. Diagnosis of CMV infection is based on virus detection in body fluids and tissues. There are several diagnostic methods for detection of CMV, and their use is primarily determined by the possibilities of the specific transplantation center. Regarding the risk of CMV infection, several categories of renal transplant recipients may be identified. The main factor for estimation of risk for development of CMV infection is donor and recipient serological status. The highest risk is associated with combination of CMV seropositive donor and CMV seronegative recipient (D+/R-). CMV infection was often fatal before introduction of potent antiviral drugs in therapeutic protocols. Contemporary treatment has significantly decreased mortality rate from the CMV infection. Several drugs are used for prevention and treatment of CMV infection: hyper immune gamma globulin, gancyclovir, valgancyclovir, valacyclovir and acyclovir, depending on the kind of treatment (prophylaxis or preemptive treatment). In the case of CMV disease, the best results may currently be achieved with the combination of hyper immune gamma globulin and intravenous gancyclovir.     

Cardiovascular pathology in renal transplant recipients

Various cardiovascular complications are among the major causes of mortality in renal transplant recipients. The authors examined the cardiovascular findings from necropsy of 18 renal transplant patients. All but three of the patients showed one or more pathological abnormalities. Five patients exhibited severe coronary arteriosclerosis with acute myocardial infarction with a history of myocardial infarction noted in four patients. In addition, one patient showed moderate and two showed mild coronary arteriosclerosis. Also prevalent were left ventricular (LV) hypertrophy (10/18), right ventricular (RV) hypertrophy (7/18), LV dilatation (4/18), RV dilatation (8/18), left atrial dilatation (3/18), and right atrial dilatation (6/18). Valvular abnormalities consisted of dilatations of mitral ring (1/18), pulmonic valve (2/18), and tricuspid valve (3/18). Pericarditis was found in two patients and aortic atherosclerosis in ten patients. Findings on routine chest roentgenograms and electrocardiograms did not always correspond with the anatomical findings noted on necropsy examination. The results demonstrate a marked increase in the incidence of various cardiac abnormalities in renal transplant recipients.     

Cutaneous complications in renal transplant recipients

Systematic review of the histologic characteristics of skin lesions biopsied and/or resected in a group of 580 renal transplant recipients collected over a 16-year period showed a total of 170 specimens from 120 patients. In this group there were 41 benign tumors, 22 infections, 35 inflammatory dermatoses, and 13 miscellaneous lesions. Fifty-nine lesions were malignant, and half of these were squamous cell carcinomas (SCCs). None were lethal or metastasized, although deeply invasive local recurrences and multiple lesions were common. Comparison with SCCs from a control group showed no clearcut differences with respect to level of invasion, grade, pattern, or presence of actinic change. Most of these lesions were found in sun-exposed areas, were associated with actinic changes, and with actinic keratoses. Problems in differentiating SCC from keratoacanthoma and the clinical implications of these difficulties are discussed in conjunction with a review of the literature.