Torque Teno Virus Load Is Associated With Centers for Disease Control and Prevention Stage and CD4+ Cell Count in People Living With Human Immunodeficiency Virus but Seems Unrelated to AIDS-Defining Events and Human Pegivirus Load.

BACKGROUND: Torque teno virus (TTV) is part of the human virome. TTV load was related to the immune status in patients after organ transplantation. We hypothesize that TTV load could be an additional marker for immune function in people living with HIV (PLWH). METHODS: In this analysis, serum samples of PLWH from the RESINA multicenter cohort were reanalyzed for TTV. Investigated clinical and epidemiological parameters included human pegivirus load, patient age and sex, HIV load, CD4+ T-cell count (Centers for Disease Control and Prevention [CDC] stage 1, 2, or 3), and CDC clinical stage (1993 CDC classification system; stage A, B, or C) before initiation of antiretroviral therapy. Regression analysis was used to detect possible associations among parameters. RESULTS: Our analysis confirmed TTV as a strong predictor of CD4+ T-cell count and CDC class 3. This relationship was used to propose a first classification of TTV load with regard to clinical stage. We found no association with clinical CDC stages A-C. The human pegivirus load was inversely correlated with HIV load but not TTV load. CONCLUSIONS: TTV load was associated with immunodeficiency in PLWH. Neither TTV nor HIV load were predictive for the clinical categories of HIV infection.

Acute Promyelocytic Leukemia With Torque Teno Mini Virus::RARA Fusion: An Approach to Screening and Diagnosis.

Acute promyelocytic leukemia (APL) with variant RARA translocation is linked to over 15 partner genes. Recent publications encompassing 6 cases have expanded the spectrum of RARA partners to torque teno mini virus (TTMV). This entity is likely underrecognized due to the lack of clinician and pathologist familiarity, inability to detect the fusion using routine testing modalities, and informatic challenges in its recognition within next-generation sequencing (NGS) data. We describe a clinicopathologic approach and provide the necessary tools to screen and diagnose APL with TTMV::RARA using existing clinical DNA- or RNA-based NGS assays, which led to the identification of 4 cases, all without other known cytogenetic/molecular drivers. One was identified prospectively and 3 retrospectively, including 2 from custom automated screening of multiple data sets (50,257 cases of hematopoietic malignancy, including 4809 acute myeloid leukemia/myeloid sarcoma/APL cases). Two cases presented as myeloid sarcoma, including 1 with multiple relapses after acute myeloid leukemia-type chemotherapy and hematopoietic stem cell transplant. Two cases presented as leukemia, had a poor response to induction chemotherapy, but achieved remission upon reinduction (including all-trans retinoic acid in 1 case) and subsequent hematopoietic stem cell transplant. Neoplastic cells demonstrated features of APL including frequent azurophilic granules and dim/absent CD34 and HLA-DR expression. RARA rearrangement was not detected by karyotype or fluorescent in situ hybridization. Custom analysis of NGS fusion panel data identified TTMV::RARA rearrangements and, in the prospectively identified case, facilitated monitoring in sequential bone marrow samples. APL with TTMV::RARA is a rare leukemia with a high rate of treatment failure in described cases. The diagnosis should be considered in leukemias with features of APL that lack detectable RARA fusions and other drivers, and may be confirmed by appropriate NGS tests with custom informatics. Incorporation of all-trans retinoic acid may have a role in treatment but requires accurate recognition of the fusion for appropriate classification as APL.

The mysterious anelloviruses: investigating its role in human diseases.

Anelloviruses (AVs) that infect the human population are members of the Anelloviridae family. They are widely distributed in human populations worldwide. Torque teno virus (TTV) was the first virus of this family to be identified and is estimated to be found in the serum of 80-90% of the human population. Sometime after the identification of TTV, Torque teno mini virus (TTMV) and Torque teno midi virus (TTMDV) were also identified and classified in this family. Since identifying these viruses, have been detected in various types of biological fluids of the human body, including blood and urine, as well as vital organs such as the liver and kidney. They can be transmitted from person to person through blood transfusions, fecal-oral contact, and possibly sexual intercourse. Recent studies on these newly introduced viruses show that although they are not directly related to human disease, they may be indirectly involved in initiating or exacerbating some human population-related diseases and viral infections. Among these diseases, we can mention various types of cancers, immune system diseases, viral infections, hepatitis, and AIDS. Also, they likely use the microRNAs (miRNAs) they encode to fulfill this cooperative role. Also, in recent years, the role of proliferation and their viral load, especially TTV, has been highlighted to indicate the immune system status of immunocompromised people or people who undergo organ transplants. Here, we review the possible role of these viruses in diseases that target humans and highlight them as important viruses that require further study. This review can provide new insights to researchers.

The kinetics of Torque Teno virus plasma load following calcineurin inhibitor dose change in kidney transplant recipients.

Torque Teno virus (TTV) is nonpathogenic, highly prevalent, and reflects the immune status of its host. Thus, TTV plasma load was suggested for the guidance of immunosuppression post solid organ transplantation. The present study was designed to determine the kinetics of TTV following changes in calcineurin inhibitor (CNI) dose. A total of 48 adult recipients of a kidney graft transplanted at the Medical University of Vienna between 2018 and 2019 with isolated changes in CNI dose were selected from the prospective TTV-POET trial. TTV plasma load was quantified by in-house PCR. At Day 30 following CNI dose adaptation (median 33% of daily dose) no changes in TTV load were noted. However, at Day 60, following CNI dose reduction a lower TTV load of 6.4 log10 c/mL (median; interquartile range [IQR] 4.9-8.1) compared with the baseline of 7.1 log10 c/mL (IQR 5.3-8.9) was noted (p = 0.001); there was also a trend toward a higher TTV load following CNI increase (6.6 log10 c/mL, IQR 4.1-9.7 vs. 5.2 log10 c/mL, IQR 4.5-6.8; p = 0.09). The data suggested that TTV load changes become noticeable only 2 months after CNI dose adaptation, which might be the ideal time point for TTV load monitoring.

High Torque teno virus load and outcome of patients undergoing allogeneic hematopoietic cell transplantation.

Quantification of Torque teno virus (TTV) load emerged as a marker of immunosuppression. Associations of TTV load with complications and survival after allogeneic hematopoietic cell transplantation (allo-HCT) were controversial in published studies. In this prospective study, we aimed to identify factors influencing TTV load after allo-HCT and to determine whether the TTV load is associated with complications or outcomes. Seventy allo-HCT recipients were included. TTV DNA load was quantified in 469 plasma samples of 70 patients from Day (D) 15 before D120 after transplantation. The influence of transplant characteristics on TTV load and the associations of TTV load with viral infections, acute graft versus host disease, mortality, and relapse were analyzed. More than 80% of patients were TTV DNA positive from D30 after transplantation onwards. Median TTV load increased between D30 and D60 post-transplantation. Patients with lymphoid malignancies had higher TTV load than those with myeloid malignancies. Myeloablative conditioning was associated with higher TTV loads. Patients with no measurable residual disease at transplant had higher TTV loads. High TTV load at D90 post-transplantation was associated with lower overall survival and at D120 post-transplantation was associated with higher relapse rate. In conclusion, TTV load at time points later than D90 after allo-HCT may be useful to assess prognosis.

Longitudinal monitoring of Torque Teno virus DNAemia in kidney transplant recipients correlates with long-term complications of inadequate immunosuppression.

Optimization of individual immunosuppression, which reduces the risks of both graft loss and patients' death, is considered the best approach to improve long-term outcomes of renal transplantation. Torque Teno Virus (TTV) DNAemia has emerged as a potential biomarker reflecting the depth of therapeutic immunosuppression during the initial year post-transplantation. However, its efficacy in long-term monitoring remains uncertain. In a cohort study involving 34 stable kidney transplant recipients and 124 healthy volunteers, we established lower and upper TTV DNAemia thresholds (3.75-5.1 log10 cp/mL) correlating with T-cell activatability, antibody response against flu vaccine, and risk for subsequent serious infections or cancer over 50 months. Validation in an independent cohort of 92 recipients confirmed that maintaining TTV DNAemia within this range in >50% of follow-up time points was associated with reduced risks of complications due to inadequate immunosuppression, including de novo DSA, biopsy-proven antibody-mediated rejection, graft loss, infections, or cancer. Multivariate analysis highlighted "in-target" TTV DNAemia as the sole independent variable significantly linked to decreased risk for long-term complications due to inadequate immunosuppression (odds ratio [OR]: 0.27 [0.09-0.77]; p = 0.019). Our data suggest that the longitudinal monitoring of TTV DNAemia in kidney transplant recipients could help preventing the long-term complications due to inadequate immunosuppression.

Attenuation of Torque teno viral load over time in kidney transplantation recipients treated with calcineurin inhibitors is mitigated after conversion to belatacept.

Torque Teno Virus (TTV) is a non-pathogenic anellovirus, highly prevalent in healthy populations. Variations in its viral load have been associated with states of diminished immunity, as occurs after organ transplantation. It is hypothesized that TTV-load might be used as a diagnostic tool to guide prescription and dosing of immunosuppressive drugs. Not much is known about the effects of combined immunosuppressive drugs on TTV replication in renal transplantation. Belatacept was introduced to counter side-effects of calcineurin inhibitors (CNI). It was never widely adopted, mainly because its association with increased risk of rejection. To investigate the differential effects of a regimen based on calcineurin inhibitors versus belatacept on TTV-loads, we measured TTV-levels in 105 patients from two randomized controlled trials in kidney transplant recipients (KTRs). We observed that time after transplantation was inversely related to TTV-levels of patients that remained on a CNI-containing regime, whereas this decline over time was diminished after conversion to belatacept. In addition, a correlation with tacrolimus-trough levels and age were found. Our study is the first report on the impact of conversion from CNI to belatacept on TTV-levels in KTR. In conclusion, the time-related decline in TTV-levels is mitigated after conversion from CNI to belatacept.

TTV and CMV viral load dynamics: Which emerges first during immunosuppression?

Novel biomarkers reflecting the degree of immunosuppression in transplant patients are required to ensure eventual personalized equilibrium between rejection and infection risks. With the above aim, Torque Teno Virus (TTV) viremia was precisely examined in a large cohort of transplanted immunocompromised patients (192 hematological and 60 solid organ transplant recipients) being monitored for Cytomegalovirus reactivation. TTV load was measured in 2612 plasma samples from 448 patients. The results revealed a significant increase in TTV viral load approximately 14 days following CMV reactivation/infection in solid organ transplant (SOT) patients. No recognizable difference in TTV load was noted among hematological patients during the entire timeframe analyzed. Furthermore, a temporal gap of approximately 30 days was noted between the viral load peaks reached by the two viruses, with Cytomegalovirus (CMV) preceding TTV. It was not possible to establish a correlation between CMV reactivation/infection and TTV viremia in hematological patients. On the other hand, the SOT patient cohort allowed us to analyze viral kinetics and draw intriguing conclusions. Taken together, the data suggest, to our knowledge for the first time, that CMV infection itself could potentially cause an increase in TTV load in the peripheral blood of patients undergoing immunosuppressive therapy.

Torque teno virus load as marker of rejection and infection in solid organ transplantation - A systematic review and meta-analysis.

Balancing immunosuppression to prevent rejection in solid organ transplant (SOT) recipients remains challenging. Torque teno virus (TTV), a commensal non-pathogenic virus, has been proposed as marker of functional immunity: higher loads correspond to over-immunosuppression, and lower loads to under-immunosuppression. This review offers an overview of the current evidence of the association between TTV-load and infection and rejection after SOT. A systematic literature search strategy, deposited in the PROSPERO registry, resulted in 548 records. After screening, 23 original and peer-reviewed articles were assessed investigating the association between TTV-load, infection and/or rejection in SOT. The Quality in Prognostic Studies (QUIPS)-tool was used to assess the risk of bias. Meta-analysis with random-effects was performed on results with similar outcomes and exposure measures. Most of the included studies involved retrospective cohorts in which the TTV-load was measured longitudinally, within the first 2 years post-transplantation. Infection outcomes differed between studies and included viral, bacterial, parasitic and fungal infections. Rejection was defined by biopsy confirmation or initiation of rejection treatment. Twelve out of 16 studies reported an association between high TTV-load and infections, whereas 13 out of 15 reported an association between low TTV-load and rejection. Meta-analysis showed an increased risk of infection (OR: 1.16, 95% CI: 1.03-1.32; HR: 1.05, 95% CI: 0.97-1.14) and a decreased risk of rejection (OR: 0.90, 95% CI: 0.87-0.94; HR: 0.74, 95% CI: 0.71-0.76) per 1 log TTV-load increase. The qualitative assessment showed varying risks of bias in the included studies. This systematic review and meta-analysis indicates that blood TTV-load measured within the first 2 years after SOT is associated with the risk of infection or allograft rejection, although substantial risk of bias in the studies included warrant cautious interpretation. The results in this review provide a rationale for larger, prospective, studies into TTV as marker of infection and rejection after SOT.

Torque Teno Virus Loads as a Marker of Immunosuppression in Pediatric Kidney Transplant Recipients.

BACKGROUND: Long-term renal function and survival after kidney transplantation rely on appropriate immunosuppressive treatment to prevent the risk of rejection. New biomarkers are needed to accurately assess the degree of immunosuppression in renal transplant recipients in order to avoid organ rejection and the development of opportunistic infections. Highly prevalent in humans, torque teno virus (TTV), which belongs to the family Anelloviridae, is a small, nonenveloped, single-stranded DNA virus which has not been linked with any specific human illness, but which constitutes a major component of the human virome. Host antiviral responses allow TTV levels to be controlled; however, viral persistence remains, explaining the high prevalence in human populations, including healthy individuals. Important confounders of TTV load include time since transplantation, age, gender, obesity, and smoking status. AIMS: TTV-based guidance of immunosuppressive drug dosing could help with risk stratification, reducing the risk of infection, graft rejection and oncologic disease on an individual level, enabling long-term patient and graft survival. METHODS: Original studies were accessed by a systematic search from electronic databases including PubMed, ScienceDirect and Wiley Online Library. RESULTS: The presented data mainly derive from adult transplant recipients showing an association between TTV plasma levels and the immune status of the host: High-TTV load and high immunosuppression are associated with a risk of infection, and low-TTV load and low immunosuppression indicate a risk of rejection. However, there is minimal information on pediatric transplant recipients with further research required in this cohort. To date, it has been demonstrated that longer posttransplant times are significantly associated with lower TTV levels in children with renal transplant. Meanwhile, an association between lower TTV loads and increased risk of graft reject during the first year of transplantation was also reported. More recently, Eibensteiner et al. revealed a robust, independent association between TTV plasma load and the onset of Cytomegalovirus and BK virus infections. CONCLUSION: Data from randomized controlled trials are still missing, even in adults, but a multicenter randomized controlled trial for TTV-guided immunosuppression in adult kidney recipients (TTVguideIT) began in 2022. There is, therefore, great promise for TTV levels to be used as a biomarker that could potentially improve both graft and patient survival in transplantation.

Torque Teno Virus: A Promising Biomarker in Kidney Transplant Recipients.

Torque Teno Virus (TTV) is a ubiquitous component of the human virome, not associated with any disease. As its load increases when the immune system is compromised, such as in kidney transplant (KT) recipients, TTV load monitoring has been proposed as a method to assess immunosuppression. In this prospective study, TTV load was measured in plasma and urine samples from 42 KT recipients, immediately before KT and in the first 150 days after it. Data obtained suggest that TTV could be a relevant marker for evaluating immune status and could be used as a guide to predict the onset of infectious complications in the follow-up of KT recipients. Since we observed no differences considering distance from transplantation, while we found a changing trend in days before viral infections, we suggest to consider changes over time in the same subjects, irrespective of time distance from transplantation.

Diversity and Long-Term Dynamics of Human Blood Anelloviruses.

Anelloviruses (AVs) are commensal members of the human blood virome. Even though it was estimated that over 90% of the human population carries AVs, the dynamics of the AV virome ("anellome") are unknown. We investigated the dynamics of blood anellomes in two healthy people followed up for more than 30 years. Both subjects were positive for AVs in the majority of samples. Alphatorquevirus (torque teno virus [TTV]) was the most common genus in both subjects, followed by Betatorquevirus (torque teno minivirus [TTMV]) and Gammatorquevirus (torque teno midivirus [TTMDV]). Almost five times more lineages were found in subject 1 than in subject 2, and the anellomes differed phylogenetically. Both anellomes remained compositionally stable, and 9 out of 64 AV lineages were detected in over half of the time points. We confirmed the long-term and short-term persistence of 13 lineages by specific quantitative PCR (qPCR). AV lineages were detected in blood for over 30 years. Noticeable differences in anellome richness were found between the tested subjects, but both anellomes remained compositionally stable over time. These findings demonstrate that the human blood anellome is personal and that AV infection is chronic and potentially commensal. IMPORTANCE Knowledge of the persistence of AVs in humans is crucial to our understanding of the nature of AV infection (chronic or acute) and the role of AV in the host. We therefore investigated the dynamics of anellovirus infection in two healthy people followed up for 30 years. Our findings suggest that the human blood anellovirus virome (anellome) remains stable and personal for decades.

Assessment of the potential value of plasma Torque Teno virus DNA load monitoring to predict cytomegalovirus DNAemia in patients with hematological malignancies treated with small molecule inhibitors: A proof-of-concept study.

It is unknown whether Torque Teno virus (TTV) DNA load monitoring could anticipate the development of infectious events in hematological patients undergoing treatment with small molecular targeting agents. We characterized the kinetics of plasma TTV DNA in patients treated with ibrutinib or ruxolitinib and assessed whether TTV DNA load monitoring could predict the occurrence of Cytomegalovirus (CMV) DNAemia or the magnitude of CMV-specific T-cell responses. Multicenter, retrospective, observational study, recruiting 20 patients treated with ibrutinib and 21 with ruxolitinib. Plasma TTV and CMV DNA loads were quantified by real-time PCR at baseline and days +15, +30, +45, +60, +75, +90, +120, +150, and +180 after treatment inception. Enumeration of CMV-specific interferon-γ (IFN-γ)-producing CD8+ and CD4+ T-cells in whole blood was performed by flow cytometry. Median TTV DNA load in ibrutinib-treated patients increased significantly (p = 0.025) from baseline (median: 5.76 log10 copies/mL) to day +120 (median: 7.83 log10 copies/mL). A moderate inverse correlation (Rho = -0.46; p < 0.001) was found between TTV DNA load and absolute lymphocyte count. In ruxolitinib-treated patients, TTV DNA load quantified at baseline was not significantly different from that measured after treatment inception (p ≥ 0.12). TTV DNA load was not predictive of the subsequent occurrence of CMV DNAemia in either patient group. No correlation was observed between TTV DNA loads and CMV-specific IFN-γ-producing CD8+ and CD4+ T-cell counts in either patient group. The data did not support the hypothesis that TTV DNA load monitoring in hematological patients treated with ibrutinib or ruxolitinib could be useful to predict either the occurrence of CMV DNAemia or the level of CMV-specific T-cell reconstitution; nevertheless, due to the small sample size, further studies involving larger cohorts are warranted to elucidate this issue.

Monitoring of plasma Torque teno virus, total Anelloviridae and Human Pegivirus 1 viral load for the prediction of infectious events and acute graft versus host disease in the allogeneic hematopoietic stem cell transplantation setting.

Anelloviridae and Human Pegivirus 1 (HPgV-1) blood burden have been postulated to behave as surrogate markers for immunosuppression in transplant recipients. Here, we assessed the potential utility plasma Torque teno virus (TTV), total Anelloviridae (TAV), and HPgV-1 load monitoring for the identification of allogeneic hematopoietic stem cell transplantation recipients (allo-HSCT) at increased risk of infectious events or acute graft versus host disease (aGvHD). In this single-center, observational study, plasma TTV DNA, TAV DNA, and HPgV-1 RNA loads were monitored in 75 nonconsecutive allo-HSCT recipients (median age, 54 years). Monitoring was conducted before at baseline or by days +30, +60, +90, +120, and +180 after transplantation. Pneumonia due to different viruses or Pneumocystis jirovecii, BK polyomavirus-associated haemorrhagic cystitis (BKPyV-HC), and Cytomegalovirus DNAemia were the infectious events considered in the current study. Kinetics of plasma TTV, TAV DNA, and HPgV-1 RNA load was comparable, with though and peak levels measured by days +30 and day +90 (+120 for HPgV-1). Forty patients (53%) developed one or more infectious events during the first 180 days after allo-HSCT, whereas 29 patients (39%) had aGvHD (grade II-IV in 18). Neither, TTV, TAV, nor HPgV-1 loads were predictive of overall infection or CMV DNAemia. A TTV DNA load cut-off ≥4.40 log10 (pretransplant) and ≥4.58 log10 (baseline) copies/mL predicted the occurrence of BKPyV-HC (sensitivity ≥89%, negative predictive value, ≥96%). TTV DNA loads ≥3.38 log10 by day +30 anticipated the occurrence of aGvHD (sensitivity, 90%; negative predictive value, 97%). Pretransplant HPgV-1 loads were significantly lower (p = 0.03) in patients who had aGvHD than in those who did not. Monitoring of TTV DNA or HPgV-1 RNA plasma levels either before or early after transplantation may be ancillary to identify allo-HSCT recipients at increased risk of BKPyV-HC or aGvHD.

Torque-teno virus for the prediction of graft rejection and infection disease after kidney transplantation: A systematic review and meta-analysis.

Torque teno virus (TTV) is a promising novel marker for quantifying the immune function in solid organ recipients, whose diagnostic accuracy of acute rejection (AR) and infection after kidney transplantation (KT) has not been evaluated. We performed a systematic review and meta-analysis to evaluate the diagnostic accuracy of TTV for discriminating AR and infection after KT. Eleven studies were included in the meta-analysis. Seven studies focused on the diagnostic accuracy of TTV for AR, and the pooled analysis indicated patients who developed AR had a significant lower TTV viral DNA load (log10 copies/mL, MD: -0.74, p < 0.01). The pooled sensitivity, specificity, and area under the receiver operating characteristics curve for TTV in AR differentiation were 0.61 (0.36-0.82), 0.81 (0.64-0.91), and 0.79 (0.75-0.82), respectively. The overall diagnostic odds ratio (DOR) was 6.74 (2.60-17.50), positive likelihood ratio (PLR) was 3.22 (1.75-5.95), and negative likelihood ratio (NLR) was 0.48 (0.27-0.84), respectively. Similarly, seven studies investigated the infection discrimination and found that patients who subsequently developed posttransplant infection had higher plasma TTV DNA loads (log10 copies/mL, MD: 0.65; p < 0.01) than those remaiing infection-free. Pooled sensitivity, specificity, and area under the receiver operating characteristics curve for TTV in infection differentiation were 0.72 (0.39-0.91), 0.57 (0.30-0.80), and 0.68 (0.64-0.72), respectively. The overall DOR was 3.28 (95% confidence interval [CI]: 2.08-5.17), the pooled PLR and NLR were 1.65 (95% CI: 1.25-2.18) and 0.50 (95% CI: 0.29-0.86), respectively. TTV might be a modest indicator for risk stratification of AR after KT, but it is a poor to discriminate posttransplant infection.

Torque teno virus (TTV): A gentle spy virus of immune status, predictive marker of seroconversion to COVID-19 vaccine in kidney and lung transplant recipients.

To date, no comprehensive marker to monitor the immune status of patients is available. Given that Torque teno virus (TTV), a known human virome component, has previously been identified as a marker of immunocompetence, it was retrospectively investigated whether TTV viral load may also represent a marker of ability to develop antibody in response to COVID-19-BNT162B2 vaccine in solid organ transplant recipients (SOT). Specifically, 273 samples from 146 kidney and 26 lung transplant recipients after successive doses of vaccine were analyzed. An inverse correlation was observed within the TTV copy number and anti-Spike IgG antibody titer with a progressive decrease in viremia the further away from the transplant date. Analyzing the data obtained after the second dose, a significant difference in TTV copy number between responsive and nonresponsive patients was observed, considering a 5 log10 TTV copies/mL threshold to discriminate between the two groups. Moreover, for 86 patients followed in their response to the second and third vaccination doses a 6 log10 TTV copies/mL threshold was used to predict responsivity to the booster dose. Although further investigation is necessary, possibly extending the analysis to other patient categories, this study suggests that TTV can be used as a good marker of vaccine response in transplant patients.

Torque teno virus viral load predicts SARS-CoV-2 vaccine response in kidney transplant recipients.

Transplant recipients display poor responses to SARS-CoV-2 mRNA vaccines. In this retrospective study, we investigate torque teno virus (TTV) viral load (VL), a ubiquitous virus reflecting global immune response levels, as a predictive factor of vaccine response in kidney transplant recipients (KTR). Four hundred and fifty-nine KTR having received two SARS-CoV-2 mRNA vaccine doses were enrolled, and 241 of them subsequently received a third vaccine dose. Antireceptor-binding domain (RBD) IgG response was assessed after each vaccine dose and TTV VL was measured in pre-vaccine samples. Prevaccine TTV VL > 6.2 log10 copies (cp)/mL was independently associated with nonresponse to two doses (odds ratio (OR) = 6.17, 95% confidence interval (CI95) = 2.42-15.78) as well as to three doses (OR = 3.62, 95% CI95 = 1.55-8.49). In nonresponders to the second dose, high TTV VL in prevaccine samples or measured before the third dose were equally predictive of lower seroconversion rates and antibody titers. High TTV VL before and during SARS-CoV-2 vaccination schedules are predictive of poor vaccine response in KTR. This biomarker should be further evaluated regarding other vaccine responses.

Respiratory torque teno virus load at emergency department visit predicts intensive care unit admission of SARS-CoV-2 infected patients.

Accurate prediction of COVID-19 severity remains a challenge. Torque teno virus (TTV), recognized as a surrogate marker of functional immunity in solid organ transplant recipients, holds the potential for assessing infection outcomes. We investigated whether quantifying TTV in nasopharyngeal samples upon emergency department (ED) admission could serve as an early predictor of COVID-19 severity. Retrospective single-center study in the ED of Saint-Louis Hospital in Paris, France. TTV DNA was quantified in nasopharyngeal swab samples collected for SARS-CoV-2 testing. Among 295 SARS-CoV-2 infected patients, 92 returned home, 160 were admitted to medical wards, and 43 to the intensive care unit (ICU). Elevated TTV loads were observed in ICU patients (median: 3.02 log copies/mL, interquartile range [IQR]: 2.215-3.825), exceeding those in discharged (2.215, [0; 2.962]) or hospitalized patients (2.24, [0; 3.29]) (p = 0.006). Multivariate analysis identified diabetes, obesity, hepatitis, fever, dyspnea, oxygen requirement, and TTV load as predictors of ICU admission. A 2.91 log10 copies/mL TTV threshold independently predicted ICU admission. Nasopharyngeal TTV quantification in SARS-CoV-2 infected patients is linked to the likelihood of ICU admission and might reflect respiratory immunosuppression.

Absence of pathogenic viruses in COVID-19 convalescent plasma.

BACKGROUND: It is important to maintain the safety of blood products by avoiding the transfusion of units with known and novel viral pathogens. It is unknown whether COVID-19 convalescent plasma (CCP) may contain pathogenic viruses (either newly acquired or reactivated) that are not routinely screened for by blood centers. METHODS: The DNA virome was characterized in potential CCP donors (n = 30) using viral genome specific PCR primers to identify DNA plasma virome members of the Herpesviridae [Epstein Barr Virus (EBV), cytomegalovirus (CMV), human herpesvirus 6A/B, human herpesvirus 7] and Anelloviridae [Torque teno viruses (TTV), Torque teno mini viruses (TTMV), and Torque teno midi viruses (TTMDV)] families. In addition, the RNA plasma virome was characterized using unbiased metagenomic sequencing. Sequencing was done on a HiSeq2500 using high output mode with a read length of 2X100 bp. The sequencing reads were taxonomically classified using Kraken2. CMV and EBV seroprevalence were evaluated using a chemiluminescent immunoassay. RESULTS: TTV and TTMDV were detected in 12 (40%) and 4 (13%) of the 30 study participants, respectively; TTMDV was always associated with infection with TTV. We did not observe TTMV DNAemia. Despite CMV and EBV seroprevalences of 33.3% and 93.3%, respectively, we did not detect Herpesviridae DNA among the study participants. Metagenomic sequencing did not reveal any human RNA viruses in CCP, including no evidence of circulating SARS-CoV-2. DISCUSSION: There was no evidence of pathogenic viruses, whether newly acquired or reactivated, in CCP despite the presence of non-pathogenic Anelloviridae. These results confirm the growing safety data supporting CCP.

Monitoring viral genomic sequences in transfusion-transmitted viruses.

BACKGROUND AND OBJECTIVES: Monitoring genomic sequences of blood-borne viruses infecting blood donors enables blood operators to undertake molecular epidemiology, confirm transfusion transmission and assess and characterize molecular and serological screening assays. The purpose of the study was to determine how blood operators globally value viral diversity surveillance and to assess its impact. MATERIALS AND METHODS: An electronic questionnaire was developed and circulated to members of the International Society of Blood Transfusion-transmitted infectious diseases working party. Responses were compiled and complete data sets were analysed. RESULTS: Ninety-seven percent of respondents agreed that monitoring viral genomic sequences was important to blood operators and the transfusion community. However, only 47% of respondents are currently doing this monitoring. The main limitations reported were a lack of financial resources and expertise. Sequencing techniques, primarily next-generation sequencing and also Sanger sequencing, were considered most appropriate, with the preferred option for testing being regional or national reference centres. Respondents agreed that engagement with public health authorities needs to be enhanced. CONCLUSION: Monitoring genomic sequences of blood-borne viruses is widely considered important by the transfusion community because of its direct applications for transfusion safety, and beyond for public health in general. Therefore, there is a need to strengthen collaboration between blood operators and public health authorities. While national and regional reference centres may be the most appropriate structure for such testing, international collaborations should not be overlooked. Overcoming financial barriers will be an important hurdle for many.