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

Development of antiviral drugs for COVID-19 in 2025: unmet needs and future challenges

INTRODUCTION

The success in the coronavirus infectious disease 2019 (COVID-19) pandemic containment largely originated from vaccine- and infection-elicited immunity, with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection only marginally mitigated by the availability of antiviral drugs. The current lack of effective antiviral prophylactic and therapeutic agents in immunocompromised patients highlights the need for a radical change in the design of both drug manufacturing and clinical trials.

AREAS COVERED

In this review, the authors summarize their suggestions for manufacturers, by reviewing classes of small molecule antivirals and passive immunotherapies and highlighting their limitations and unexploited potential.

EXPERT OPINION

Molecular and serological testing of patients can improve appropriateness. Efficacy of antivirals can be improved by combining different therapeutic classes while preserving economical sustainability. Respiratory delivery should be better investigated in clinical trials.

Torquetenovirus detection in exosomes enriched vesicles circulating in human plasma samples

BACKGROUND

Torquetenovirus (TTV) belongs to Anelloviridae family, infects nearly all people indefinitely without causing overt disease establishing a fine and successful interaction with the host. Increasing evidence have shown some human viruses exploit extracellular vesicles thereby helping viral persistence in the host. Here, the presence of TTV in extracellular vesicles circulating in human plasma was investigated.

METHODS

TTV DNA was quantified in plasma-derived exosomes from 122 samples collected from 97 diseased patients and 25 healthy donors. Exosomes enriched vesicles (EEVs) were extracted from plasma and characterized by Nanoparticle tracking analysis, by western blot for presence of tetraspanin CD63, CD81 and annexin II protein and, finally, by electron microscopy (EM). Presence and quantitation of TTV DNA were assessed with an universal single step real-time TaqMan PCR assay.

RESULTS

Preliminary investigation showed that the human plasma extracted extracellular vesicles exhibited a main size of 70 nm, had concentration of 2.5 × 10⁹/ml, and scored positive for tetraspanin CD63, CD81 and annexin II, typical characteristic of the exosomes vesicles. EEVs extracted from pooled plasma with TTV DNA viremia of 9.7 × 10⁴ copies/ml showed to contain 6.3 × 10² TTV copies/ml, corresponding to 0.65% of total viral load. Important, TTV yield changed significantly following freezing/thawing, detergents and DNAse treatment of plasma before EEVs extraction. EEVs purified by sucrose-density gradient centrifugation and analysis of gradient fraction positive for exosomes marker CD63 harbored 10² TTV copies/ml. Moreover, EM evidenced the presence of TTV-like particles in EEVs. Successive investigation of plasma EEVs from 122 subjects (37 HIV-positive, 20 HCV infected, 20 HBV infected, 20 kidney transplant recipients, and 25 healthy) reported TTV DNA detection in 42 (34%) of the viremic samples (37 were from diseased patients and 5 from healthy people) at a mean level of 4.8 × 10³ copies/ml. The examination of EEVs selected samples reported the presence of TTV genogroup 1, 3, 4 and 5, with genogroup 3 highly observed.

CONCLUSIONS

Collectively, although these observations should be confirmed by further studies, circulation of TTV particles in EEVs opens new avenues and mechanistic insights on the molecular strategies adopted by anelloviruses to persist in the host.

Detection and molecular characterization of Torque Teno Virus (TTV) in Uruguay

Torque Teno Virus (TTV), member of Anelloviridae family, is considered a worldwide distributed emergent virus and is currently classified into seven genogroups. Interestingly, the pathogenicity of TTV remains unclear. However, it has been constantly associated to hepatitis cases of unknown etiology (HUE) as well as extensively studied in concurrent infections with Hepatitis B Virus (HBV), Hepatitis C Virus (HCV) and Human Immunodeficiency Virus type 1 (HIV-1). In South America, TTV epidemiological data is scant, involving some studies from Brazil, Venezuela, Colombia and Bolivia. The aim of this work was to investigate for the first time in Uruguay the presence of TTV by a nested-PCR system in 85 human serum samples infected with HBV and/or HCV and/or HIV-1 and in HUE cases. Overall, our results reported a TTV infection rate of 79% (67/85). Furthermore, the molecular characterization of Uruguayan strains revealed that one of them clustered in genogroup 1, while the remaining ones formed separate clusters closely related to genogroup 3, which should be confirmed by complete genome sequencing. Further investigation about TTV circulation in Uruguayan population is needed in order to provide additional information about the genetic variability and TTV epidemiology in South America.

Human anelloviruses and the central nervous system

Torque teno virus and related anelloviruses are a recent addition to the list of agents that cause chronic productive infections and high levels of plasma viraemia in humans. Many aspects of the natural history and pathogenesis of these under many respects surprising viruses are still poorly understood. In this review, we briefly outline the general properties of anelloviruses, examine what is currently known about the interactions they establish with the central nervous system (CNS), and discuss the possible pathological consequences.

High frequency of SEN virus infection in thalassemic patients and healthy blood donors in Iran

Background

SEN virus is a blood-borne, circular ssDNA virus and possessing nine genotypes (A to I). Among nine genotypes, SENV-D and SENV-H genotypes have the strong link with patients with unknown (none-A to E) hepatitis infections. Infection with blood-borne viruses is the second important cause of death in thalassemic patients. The aim of this study was to determine the frequency of SENV-D and SENV-H genotypes viremia by performing nested-PCR in 120 and 100 sera from healthy blood donors and thalassemic patients in Guilan Province, North of Iran respectively. Also, to explicate a possible role of SEN virus in liver disease and established changes in blood factors, the serum aminotransferases (ALT and AST) and some of the blood factors were measured.

Results

Frequency of SENV-D, SENV (SENV-H or SENV-D) and co-infection (both SENV-D and SENV-H) viremia was significantly higher among thalassemic patients than healthy individuals. Frequency of SENV-H viremia was significantly higher than SENV-D among healthy individuals. In comparison to SENV-D negative patients, the mean of mean corpuscular hemoglobin was significantly higher in SENV-D positive and co-infection cases (P < 0.05). The means of AST and ALT were significantly higher in thalassemic patients than healthy blood donors, but there were not any significant differences in the means of the liver levels between SENV-positive and -negative individuals in healthy blood donors and thalassemic patients. High nucleotide homology observed among PCR amplicon's sequences in healthy blood donors and thalassemic patients.

Conclusions

The high rate of co-infection shows that different genotypes of SENV have no negative effects on each other. The high frequency of SENV infection among thalassemic patients suggests blood transfusion as main route of transmission. High frequency of SENV infection in healthy individuals indicates that other routes rather than blood transfusion also are important. Frequency of 90.8% of SENV infection among healthy blood donors as well as high nucleotide homology of sequenced amplicons between two groups can probably suggest that healthy blood donors infected by SENV act partly as a source of SENV transmission to the thalassemic patients. In conclusion, SENV-D isolate in Guilan Province may be having a pathogenic agent for thalassemic patients.

Immunobiology of the Torque teno viruses and other anelloviruses

Many features of the Torque teno virus and the other anelloviruses (AVs) that have been identified after this virus was discovered in 1997 remain elusive. The immunobiology of the AVs is no exception. However, evidence is progressively accumulating that at least some AVs have an interesting interplay with cells and soluble factors known to contribute to the homeostasis of innate and adaptive immunity. Evidence is also accumulating that this interplay can have a significant impact on how effectively an infected host can deal with superimposed infectious and non-infectious noxae. This review article discusses the scanty information available on these aspects and highlights the ones that would be more urgent to precisely understand in order to get an adequate assessment of how important for human health these extremely ubiquitous and pervasive viruses really are.

Prevalence and impact of GBV-C, SEN-V and HBV occult infections in HIV-HCV co-infected patients on HCV therapy

BACKGROUND/AIMS

It has been suggested that, in HIV-HCV co-infected patients, co-infections with other viruses may affect the response to HCV therapy. We aimed to assess the prevalence of GBV-C, SEN-V and occult HBV infections, their impact on HCV and HIV infections and on the response to HCV therapy in HIV-HCV co-infected patients.

METHODS

Three-hundred and sixty eight patients were tested before starting interferon-ribavirin for the presence of occult hepatitis B DNA, GBV-C RNA and SEN-V DNA by using real time PCR. Clinical, immunological, virological, histological characteristics and response to HCV therapy were compared according to the presence or not of each viral co-infection.

RESULTS

HBV DNA, GBV-C RNA and SEN-V DNA were found in 5 (1.4%, CI95%: 0.2-2.4%), 104 (29.9%, CI95%: 25.1-34.7%) and 209 patients (57.9%, CI95%: 52.8-63.0%), respectively. GBV-C positive patients had significantly higher CD4 count at baseline, during and after HCV therapy, even after stratification on antiretroviral treatment. No other significant difference was observed according to the presence or not of GBV-C or SEN-V co-infection, in particular regarding virological responses to HCV combination therapy.

CONCLUSIONS

There is no reason to withhold HCV therapy in HIV infected patients who have access to HAART, because of occult HBV, GBV-C or SEN-V co-infections.