The Torque Teno Virus Titer in Saliva Reflects the Level of Circulating CD4+ T Lymphocytes and HIV in Individuals Undergoing Antiretroviral Maintenance Therapy

IntroductionTorque teno virus (TTV) is a non-pathogenic virus present in body fluids. Its titer in the circulation increases in association with immune suppression, such as in HIV-infected individuals. We evaluated if the TTV titer in saliva from HIV-positive individuals undergoing antiretroviral therapy (ART) was related to the circulating CD4+ T lymphocyte concentration and the HIV titer.MethodsSaliva was collected from 276 asymptomatic individuals undergoing ART, and an additional 48 individuals positive for AIDS-associated Kaposi's Sarcoma (AIDS-KS). The salivary TTV titer was measured by gene amplification analysis. The circulating CD4+ T lymphocyte and HIV levels were obtained by chart review.ResultsTTV was detectable in saliva from 80% of the asymptomatic subjects and 87% of those with AIDS-KS. In the asymptomatic group the median log10 TTV titer/ml was 3.3 in 200 males vs. 2.4 in 76 females (p < 0.0001). TTV titer/ml was 3.7 when HIV was acquired by intravenous drug usage, 3.2 when by sexual acquisition and 2.4 when blood transfusion acquired. The salivary TTV titer was inversely correlated with the circulating CD4+ T lymphocyte level (p < 0.0001) and positively correlated with the circulating HIV concentration (p = 0.0005). The median salivary TTV titer and circulating HIV titer were higher, and the CD4+ count was lower, in individuals positive for AIDS-KS than in the asymptomatic subjects (p < 0.0001).ConclusionThe TTV titer in saliva is a potential biomarker for monitoring immune status in individuals undergoing ART.

Torque Teno Virus in Nasopharyngeal Aspirate of Children With Respiratory Infections

Torque teno virus (TTV) is responsible for persistent infections and is considered a marker of immune function. The role of TTV as a facilitator of respiratory infections(RIs) is unknown. We aimed to estimate the prevalence of TTV in the nasopharyngeal aspirate (NPA) of hospitalized children with RIs and correlate them with outcomes and immune response. NPA was taken for testing 16 respiratory viruses by RT-polymerase chain reaction (PCR), TTV PCR, and immunological study.Sixty hospitalized children with an RI and 3 healthy control infants were included. A total of 51/60 patients had a positive common respiratory viral (CRV) identification. A total of 24/63 (38.1%) children were TTV+ and had other CRVs in 95.8% of cases vs 74.4% in TTV- (p=0.029). TTV+ patients tended to be older, have fever, and need PICU admission more often than TTV- patients. Abnormal chest X-ray was more frequent in the TTV+ patients, OR 2.6(95% CI:1.3-5.2).The genetic expression of filaggrin (involved in epithelial barrier integrity) was lower in TTV+ patients; however, levels of filaggrin in the NPA were increased.In summary, TTV infection is common in children with RI and could be associated with pneumonia, greater severity, and alteration in filaggrin gene expression and protein release.

Phylogenetic and molecular evolutionary analysis of SENV DNA isolated from Iraqi Hepatitis Patients

SEN Virus (SENV) is a newly discovered group of transmissible, hepatotropic, single-stranded, circular, non-enveloped DNA viruses that are distantly linked to the widely distributed Torque Teno Virus (TTV) family. This research aimed to use nucleotide sequencing to identify the genetic alterations of SEN-V and to investigate the similarities between isolates. Seven DNA samples of SENV, which were previously extracted from blood of post transfusion hepatitis, were used to identify the genetic variation of SEN-V by nucleotide sequencing. According to the current analysis results, specific primer pairs were used to detect SENV DNA sequences isolated from Iraqi patients with hepatitis; however, those specific primers can also detect two new variants of SENV that are closely related to the Torque Teno Virus. In addition, four SENV isolates showed several substitution mutations, and one of them revealed the replacement of Proline (P) at position 11 with Serine (S). Only one local isolate of SENV was 100% identical to the Iranian isolate (GenBank acc. no. GQ452051.1) from thalassemia.

Detection and genetic characterization of the novel torque teno virus group 6 in Taiwanese general population

Torque teno virus (TTV) is one of the most common human viruses and can infect an individual with multiple genotypes chronically and persistently. TTV group 6 is a recently discovered phylogenetic group first isolated from eastern Taiwan indigenes, but whether the TTV group 6 was also prevalent in the general population still unknown. One hundred and three randomly collected blood samples from general population and 66 TTV positive DNA samples extracted from Taiwan indigenes were included. A group-6-specific PCR was developed for re-screen over TTV positive samples. Two TTV group 6 positive samples from general population were cloned and sequenced for identifying mix-infected TTVs and confirming their classification by maximum-likelihood and Bayesian inference phylogeny. TTV group 6 can be detected in 4.5% (4/89) and 7.6% (5/66) of TTV positive samples from Taiwanese general population and eastern Taiwan indigenes, respectively. Sample VC09 was mix-infected with TTV groups 3 and 6. Sample VC99 was mix-infected with TTV groups 3, 4 and 6. A highly diverse triple overlapping region was observed, which may represent a unique phenomenon of TTV. The group-6-specific PCR can successfully detect TTV group 6. TTV group 6 may be prevalent worldwide regardless of the geographic region and/or ethnic groups.