Classification of Hepatitis C Virus Type 2 Isolates by Phylogenetic Analysis of Core and NS5 Regions

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Cyclovirus Vietnam DNA in immunodeficient patients

Cyclovirus Vietnam (CyCV-VN) is a CyCV detected in 2013 from cerebrospinal fluid (CSF) samples of patients with neurological disorders. Information on prevalence, pathogenesis and disease association of CyCV-VN is still very patchy

Rapid Increase in Total Torquetenovirus (TTV) Plasma Viremia Load Reveals an Apparently Transient Superinfection by a TTV of a Novel Group 2 Genotype

An apparently transient infection by a superimposed torquetenovirus (TTV) in a subject who already carried three different genotypes of the virus is described. The superinfection induced a rapid increase in the plasma TTV load and a decline in immunocomplexed virus. The superinfecting TTV was a novel group 2 genotype

Divergent evolution of hepatitis C virus in liver and peripheral blood mononuclear cells of infected patients

In infected individuals, hepatitis C virus (HCV) exists as a variably complex population of related genetic variants known as quasispecies. The quasispecies of HCV were studied previously in 10 chronically infected patients by single-strand conformation polymorphism analysis of a segment of the envelope gene E2/ NS1 containing the hypervariable region 1 and it was found that certain variants (LC variants) were present both in the liver and in peripheral brood mononuclear cells (PBMC), others (L variants) were present in the liver but not in the PBMC, and still others (C variants) showed the opposite distribution. The sequence data obtained from nine such patients are reported, indicating that, within individual subjects, L and C variants are distinct phylogenetically. Results are described on the growth of HCV in stimulated healthy donor PBMC cultures supporting the concept that genetic divergence might stem, at least in part, from virus adaptation to growth in different cell types. This information may help to understand how HCV persists and produces disease in infected patients, especially with regard to extrahepatic pathology. J. Med. Virol. 57.57-63, 1999. (C) 1999 Wiley-Liss, Inc

Low prevalence of TT virus in the cerebrospinal fluid of viremic patients with central nervous system disorders

TT virus (TTV) is a widespread infectious agent of humans identified in 1998. In infected individuals, TTV induces persistent viremia but its life cycle and pathogenic potential are still poorly understood. In the present study, the presence of TTV DNA in 32 consecutive paired serum and cerebrospinal fluid (CSF) samples from patients with neurological (mainly multiple sclerosis) disorders was investigated by means of a sensitive quantitative real-time PCR assay. Of the 24 patients who were found to carry TTV DNA in serum, 3 also had detectable TTV DNA in their CSF. Two TTV positive CSF samples had markers indicative of blood contamination or a disrupted blood-brain barrier and contained considerably lower TTV loads as compared with the corresponding serum samples, thus suggesting that the virus they contained was of plasma origin. These findings indicated that in general TTV does not permeate effectively an intact blood-brain barrier. Furthermore, the CNS does not represent a common site of TTV replication and persistence. However, at least one exception was observed: the third TTV positive CSF sample (obtained from a patient with subacute dementia of unknown origin) showed no markers suggestive of disrupted blood-brain barrier or blood contamination and had a TTV DNA concentration similar to that found in the patient's serum. In addition, the TTV isolates detected in the two body fluids were distinct genetically. The detection of TTV DNA in CSF is of considerable interest but the clinical significance remains unknown. (C) 2001 Wiley-Liss, Inc

Rapid changes in hepatitis C virus quasispecies produced by a single dose of IFN-alpha in chronically infected patients

The effects of a single dose of 3 international megaunits of interferon-alpha 2b (IFN-alpha 2b) on hepatitis C virus (HCV) load and quasispecies were examined 24 h after administration in 12 previously untreated, chronically infected patients. All patients had viremia loads appreciably reduced relative to baseline values, thus confirming that the viral load is rapidly affected by IFN-alpha 2b. Five patients also exhibited changes in plasma HCV quasispecies composition that were clearly evident by single-strand conformation polymorphism, analysis, thus indicating that one dose of IFN-alpha 2b may suffice to produce rapid perturbations in the genetic heterogeneity of circulating HCV, Prior to IFN-alpha 2b administration, 3 patients exhibited viral quasispecies differences between plasma and peripheral blood mononuclear cells (PBMC), Interestingly, in 2 such patients, the viral quasispecies found in the 24-h plasma resembled that in the pre-IFN PBMC. The latter finding raises the possibility that in these patients, the differences in quasispecies composition between pre-IFN and post-IFN plasma resulted from increased representation of lymphoid tissue-originated variants in the latter sample, possibly because of poor sensitivity to IFN-alpha 2b of HCV replication in the lymphoid compartment

Role of Hematopoietic Cells in the Maintenance of Chronic Human Torquetenovirus Plasma Viremia▿

Many aspects of the life cycle of torquetenoviruses (TTVs) are essentially unexplored. In particular, it is still a matter of speculation which cell type(s) replicates the viruses and maintains the generally high viral loads found in the blood of infected hosts. In this study, we sequentially measured the TTV loads in the plasma of four TTV-positive leukemia patients who were strongly myelosuppressed and then transplanted with haploidentical hematopoietic stem cells. The findings provide clear quantitative evidence for an extremely important role of hematopoietic cells in the maintenance of TTV viremia