Cytomegalovirus Replication Research Articles

E2F3-dependent activation of FAM111B restricts mouse cytomegalovirus replication in primate cells.

Viruses must counteract host cell defenses to facilitate viral replication. Viruses with a narrow host range, such as the cytomegaloviruses, are unable to counteract cellular defenses in cells of a foreign species. However, little is known about the cellular host range factors restricting cytomegalovirus replication. Here, we show that mouse cytomegalovirus (MCMV) induces the expression of the FAM111 proteases and that FAM111B, but not FAM111A that has previously been shown to restrict the replication of polyomavirus and orthopoxvirus host range mutants, acts as a cellular factor suppressing MCMV replication in human and rhesus monkey cells. The identification of FAM111B as a host range factor should provide new insight into the physiological functions of this poorly characterized protein.

Corilagin inhibits human cytomegalovirus infection and replication via activating the cGAS-STING signaling pathway in vitro and in vivo

AimThe existence of human cytomegalovirus (HCMV) is extremely widespread, causing serious diseases in patients with low immune function. The purpose of this study is to explore the efficacy and mechanism of Corilagin in the control of CMV infection, in order to provide scientific basis for the control of CMV infection. MethodsOur study employed an animal model in Balb/c mice, infected with MCMV, alongside cellular models in HFF cells and THP-1 cells, stimulated with HCMV. The expression of cGAS-STING signaling pathway molecules was detected in liver tissue, lung tissue, serum, cells and cell supernatant. The liver function and histopathological changes of mice were evaluated. ResultsIn vivo and in vitro experiments showed that Corilagin significantly inhibits CMV levels and attenuates pathological damage in liver and lung tissues in vivo, and similarly inhibits viral load in cells in vitro. Corilagin promotes the expression levels of STING and its downstream molecules in vivo and in vitro. Inhibition/down-regulation of STING significantly promotes CMV replication, on the contrary, activation/up-regulation of STING inhibits CMV replication, and Corilagin also promotes the expression levels of molecules related to the cGAS-STING signaling pathway in the above cases. ConclusionCorilagin could effectively inhibit the infection and replication of CMV in vitro and in vivo, which may be through the activation of cGAS-STING signaling pathway.

Targeting the host transcription factor HSF1 prevents human cytomegalovirus replication in vitro and in vivo.

Inhibiting of HSF1 as a host-directed antiviral therapy attenuates HCMV replication in vitro and in vivo.

SNX27:Retromer:ESCPE-1-mediated early endosomal tubulation impacts cytomegalovirus replication.

Cytomegaloviruses (CMVs) extensively reorganize the membrane system of the cell and establish a new structure as large as the cell nucleus called the assembly compartment (AC). Our previous studies on murine CMV (MCMV)-infected fibroblasts indicated that the inner part of the AC contains rearranged early endosomes, recycling endosomes, endosomal recycling compartments and trans-Golgi membrane structures that are extensively tubulated, including the expansion and retention of tubular Rab10 elements. An essential process that initiates Rab10-associated tubulation is cargo sorting and retrieval mediated by SNX27, Retromer, and ESCPE-1 (endosomal SNX-BAR sorting complex for promoting exit 1) complexes. The aim of this study was to investigate the role of SNX27:Retromer:ESCPE-1 complexes in the biogenesis of pre-AC in MCMV-infected cells and subsequently their role in secondary envelopment and release of infectious virions. Here we show that SNX27:Retromer:ESCPE1-mediated tubulation is essential for the establishment of a Rab10-decorated subset of membranes within the pre-AC, a function that requires an intact F3 subdomain of the SNX27 FERM domain. Suppression of SNX27-mediated functions resulted in an almost tenfold decrease in the release of infectious virions. However, these effects cannot be directly linked to the contribution of SNX27:Retromer:ESCPE-1-dependent tubulation to the secondary envelopment, as suppression of these components, including the F3-FERM domain, led to a decrease in MCMV protein expression and inhibited the progression of the replication cycle. This study demonstrates a novel and important function of membrane tubulation within the pre-AC associated with the control of viral protein expression.

G-quadruplex as an essential structural element in cytomegalovirus replication origin

G-quadruplex (G4) structures are found in eukaryotic cell replication origins, but their role in origin function remains unclear. In this study G4 motifs are found in the lytic DNA replication origin (oriLyt) of human cytomegalovirus (HCMV) and recombinant viruses show that a G4 motif in oriLyt essential region I (ER-I) is necessary for viral growth. Replication assays of oriLyt-containing plasmids and biochemical/biophysical analyses show that G4 formation in ER-I is crucial for viral DNA replication. G4 pull-down analysis identifies viral DNA replication factors, such as IE2, UL84, and UL44, as G4-binding proteins. In enzyme-linked immunosorbent assays, specific G4-binding ligands inhibit G4 binding by the viral proteins. The Epstein-Barr virus oriLyt core element also forms a stable G4 that could substitute for the oriLyt ER-I G4 in HCMV. These results demonstrate that viral G4s in replication origins represent an essential structural element in recruiting replication factors and might be a therapeutic target against viral infections.

Establishment of a Luciferase-Based Reporter System to Study Aspects of Human Cytomegalovirus Infection, Replication Characteristics, and Antiviral Drug Efficacy.

Human cytomegalovirus (HCMV) represents a highly medically important pathogen which has constantly been the subject of both molecular and clinical investigations. HCMV infections, especially those in high-risk patients, still raise many unanswered questions, so current investigations are focused on viral pathogenesis, vaccine development, and options for antiviral drug targeting. To this end, the use of suitable viral strains as well as recombinant reporter constructs in cultured cells and model systems has specific significance. We previously reported on the application of various herpesviruses that express green, red, or related fluorescent proteins, especially in the fields of virus-host interaction and antiviral research. Here, we characterized a recombinant version of the clinically relevant and cell type-adaptable HCMV strain TB40, which expresses firefly luciferase as a quantitative reporter of viral replication (TB40-FLuc). The data provide evidence for five main conclusions. First, HCMV TB40-FLuc is employable in multiple settings in primary human cells. Second, viral reporter signals are easily quantifiable, even at early time points within viral replication. Third, the FLuc reporter reflects the kinetics of viral intracellular replication, cascade-like viral IE-E-L protein production, and progeny release. Fourth, as relates to specific applications of the TB40-FLuc system, we demonstrated the reliability of quantitative antiviral compound determination in multi-well formats and its independence from fluorescence-based measurements in the case of autofluorescent inhibitors. Finally, we illustrated increased reporter sensitivity in comparison to other recombinant HCMVs. In essence, recombinant HCMV TB40-FLuc combines several molecular properties that are considered beneficial in studies on viral host tropism, replication efficiency, and antiviral drug assessment.

Cytomegalovirus-induced peroxynitrite promotes virus entry and contributes to pathogenesis in a murine model of infection.

Human cytomegalovirus (HCMV) causes significant disease in individuals with impaired or immature immune systems, such as transplant patients and after congenital infection. Antiviral drugs that target the virus directly are toxic and are susceptible to antiviral drug resistance due to virus mutations. An alternate strategy is to target processes within host cells that are required by the virus for replication. Herein, we show that HCMV infection triggers a highly reactive molecule, peroxynitrite, during the initial stages of infection. Peroxynitrite was required for the initial entry of the virus into the cell and promotes virus replication in multiple cell types, suggesting a broad pro-viral function. Importantly, targeting peroxynitrite dramatically inhibited cytomegalovirus replication in cells in the laboratory and in mice, suggesting that therapeutic targeting of this molecule and/or the cellular functions it regulates could represent a novel strategy to inhibit HCMV infection.

Evaluation of Frequency of CMV Replication and Disease Complications Reveals New Cellular Defects and a Time Dependent Pattern in CVID Patients

PurposeCommon Variable Immunodeficiency (CVID) is characterized by hypogammaglobulinemia and failure of specific antibody production due to B-cell defects. However, studies have documented various T-cell abnormalities, potentially linked to viral complications. The frequency of Cytomegalovirus (CMV) replication in CVID cohorts is poorly studied. To address this gap in knowledge, we set up an observational study with the objectives of identifying CVID patients with active viraemia (CMV, Epstein-Barr virus (EBV)), evaluating potential correlations with immunophenotypic characteristics, clinical outcome, and the dynamic progression of clinical phenotypes over time.Methods31 CVID patients were retrospectively analysed according to viraemia, clinical and immunologic characteristics. 21 patients with non CVID humoral immunodeficiency were also evaluated as control.ResultsActive viral replication of CMV and/or EBV was observed in 25% of all patients. CMV replication was detected only in CVID patients (16%). CVID patients with active viral replication showed reduced HLA-DR+ NK counts when compared with CMV-DNA negative CVID patients. Viraemic patients had lower counts of LIN−DNAMbright and LIN−CD16+ inflammatory lymphoid precursors which correlated with NK-cell subsets. Analysis of the dynamic progression of CVID clinical phenotypes over time, showed that the initial infectious phenotype progressed to complicated phenotypes with time. All CMV viraemic patients had complicated disease.ConclusionTaken together, an impaired production of inflammatory precursors and NK activation is present in CVID patients with active viraemia. Since “Complicated” CVID occurs as a function of disease duration, there is need for an accurate evaluation of this aspect to improve classification and clinical management of CVID patients.

Evaluation of CMV DNA Antigenemia Status in Patients With Allogeneic Bone Marrow Transplant

Purpose: The risk of cytomegalovirus (CMV) reactivation following allogeneic hematopoietic stem cell transplantation (ASCT) reaches 30-50%, and there are numerous diagnostic tests to detect CMV replication. The most common tests used in this group of patients include 65kDa phosphoprotein (pp65) antigenemia immunofluorescence assay and nucleic-acid-based quantitative CMV-DNA polymerase chain reaction (qPCR). Material and Methods: In this study, patients who underwent ASCT and developed CMV positivity from 2009 to 2016 in our hospital were evaluated retrospectively. The study included samples of the same patient with antigenemia and CMV-DNA qPCR test for up to 48 hours. The study aimed to determine the factors affecting CMV DNA antigenemia and compare CMV DNA PCR and pp65 antigenemia immunofluorescence assay. Results: The results of 138 specimens of 39 patients who underwent ASCT were evaluated. The mean value of CMV PCR, which was positive for both tests, was 57.887 copies/ml (70- 1.213.633 copies/ml) and a significant correlation was found between the two tests and the positive samples (p = 0.018). The ROC analysis showed that 322 copies/ml CMV viral load in plasma corresponds to ≥1 antigen-positive cells/200 thousand leukocytes (Sensitivity: 68.5%; Specificity: 31.5%). CMV infection was observed in 32 samples; CMV DNA cut-off values of the reference according to CMV DNA PCR and antigenemia results, compared to the development of CMV infection, presented a significant correlation (p=0.004). Conclusion: Although there is a common agreement between antigenemia and CMV DNA PCR tests, one should keep in mind that the sensitivity of antigenemia test is low especially in the neutropenic period.

Structure-guided mutagenesis targeting interactions between pp150 tegument protein and small capsid protein identify five lethal and two live-attenuated HCMV mutants

Human cytomegalovirus (HCMV) replication relies on a nucleocapsid coat of the 150 kDa, subfamily-specific tegument phosphoprotein (pp150) to regulate cytoplasmic virion maturation. While recent structural studies revealed pp150-capsid interactions, the role of specific amino-acids involved in these interactions have not been established experimentally. In this study, pp150 and the small capsid protein (SCP), one of pp150's binding partners found atop the major capsid protein (MCP), were subjected to mutational and structural analyses. Mutations to clusters of polar or hydrophobic residues along the pp150-SCP interface abolished viral replication, with no replication detected in mutant virus-infected cells. Notably, a single amino acid mutation (pp150 K255E) at the pp150-MCP interface significantly attenuated viral replication, unlike in pp150-deletion mutants where capsids degraded outside host nuclei. These functionally significant mutations targeting pp150-capsid interactions, particularly the pp150 K255E replication-attenuated mutant, can be explored to overcome the historical challenges of developing effective antivirals and vaccines against HCMV infection.

Letermovir prophylaxis for cytomegalovirus in lung-transplant recipients: a comprehensive study with literature review of off-label use and real-world experiences

Letermovir, initially approved for cytomegalovirus (CMV) prophylaxis in hematopoietic stem-cell transplantation, has gained attention for off-label use in lung-transplant (LTx) recipients. Given the high susceptibility of LTx recipients to CMV infection, this study explores the effectiveness and safety of letermovir prophylaxis. A retrospective analysis of using letermovir for LTx recipients at Tohoku University Hospital (January 2000 to November 2023) was conducted. Case summaries from other Japanese transplant centers and a literature review were included. Six cases at Tohoku University Hospital and one at Kyoto University Hospital were identified. Prophylactic letermovir use showed positive outcomes in managing myelosuppression and preventing CMV replication. The literature review supported the safety of letermovir in high-risk LTx recipients. Despite limited reports, our findings suggest letermovir’s potential as prophylaxis for LTx recipients intolerant to valganciclovir. Safety, especially in managing myelosuppression, positions letermovir as a promising option. However, careful consideration is important in judiciously integrating letermovir into the treatment protocol.

Human cytomegalovirus (CMV) dysregulates neurodevelopmental pathways in cerebral organoids

Human cytomegalovirus (CMV) infection is the leading non-genetic aetiology of congenital malformation in developed countries, causing significant fetal neurological injury. This study investigated potential CMV pathogenetic mechanisms of fetal neural malformation using in vitro human cerebral organoids. Cerebral organoids were permissive to CMV replication, and infection dysregulated cellular pluripotency and differentiation pathways. Aberrant expression of dual-specificity tyrosine phosphorylation-regulated kinases (DYRK), sonic hedgehog (SHH), pluripotency, neurodegeneration, axon guidance, hippo signalling and dopaminergic synapse pathways were observed in CMV-infected organoids using immunofluorescence and RNA-sequencing. Infection with CMV resulted in dysregulation of 236 Autism Spectrum Disorder (ASD)-related genes (p = 1.57E-05) and pathways. This notable observation suggests potential links between congenital CMV infection and ASD. Using DisGeNET databases, 103 diseases related to neural malformation or mental disorders were enriched in CMV-infected organoids. Cytomegalovirus infection-related dysregulation of key cerebral cellular pathways potentially provides important, modifiable pathogenetic mechanisms for congenital CMV-induced neural malformation and ASD.

Human trophoblast stem cells restrict human cytomegalovirus replication.

Placental infection plays a central role in human cytomegalovirus (HCMV) pathogenesis during pregnancy, but the species specificity of HCMV and the limited availability and lifespan of primary trophoblasts have been persistent barriers to understanding how infection impacts this vital organ. Human trophoblast stem cells (TSCs) represent a new approach to modeling viral infection early in placental development. This study reveals that TSCs, like other stem cell types, restrict HCMV replication. However, infection perturbs the expression of genes involved in differentiation and cell fate determination, pointing to a mechanism by which HCMV could cause placental injury.

The Conversion From Mycophenolic Acid to Mammalian Target of Rapamycin Inhibitor Reduces the Incidence of Cytomegalovirus Replication in Belatacept-Treated Kidney-Transplant Recipients

The Conversion From Mycophenolic Acid to Mammalian Target of Rapamycin Inhibitor Reduces the Incidence of Cytomegalovirus Replication in Belatacept-Treated Kidney-Transplant Recipients

Bisbenzimide compounds inhibit the replication of prototype and pandemic potential poxviruses.

We previously identified the bisbenzimide Hoechst 33342 (H42) as a potent multi-stage inhibitor of the prototypic poxvirus, the vaccinia virus (VACV), and several parapoxviruses. A recent report showed that novel bisbenzimide compounds similar in structure to H42 could prevent human cytomegalovirus replication. Here, we assessed whether these compounds could also serve as poxvirus inhibitors. Using virological assays, we show that these bisbenzimide compounds inhibit VACV spread, plaque formation, and the production of infectious progeny VACV with relatively low cell toxicity. Further analysis of the VACV lifecycle indicated that the effective bisbenzimide compounds had little impact on VACV early gene expression but inhibited VACV late gene expression and truncated the formation of VACV replication sites. Additionally, we found that bisbenzimide compounds, including H42, can inhibit both monkeypox and a VACV mutant resistant to the widely used anti-poxvirus drug TPOXX (Tecovirimat). Therefore, the tested bisbenzimide compounds were inhibitors of both prototypic and pandemic potential poxviruses and could be developed for use in situations where anti-poxvirus drug resistance may occur. Additionally, these data suggest that bisbenzimide compounds may serve as broad-activity antiviral compounds, targeting diverse DNA viruses such as poxviruses and betaherpesviruses.IMPORTANCEThe 2022 mpox (monkeypox) outbreak served as a stark reminder that due to the cessation of smallpox vaccination over 40 years ago, most of the human population remains susceptible to poxvirus infection. With only two antivirals approved for the treatment of smallpox infection in humans, the need for additional anti-poxvirus compounds is evident. Having shown that the bisbenzimide H33342 is a potent inhibitor of poxvirus gene expression and DNA replication, here we extend these findings to include a set of novel bisbenzimide compounds that show anti-viral activity against mpox and a drug-resistant prototype poxvirus mutant. These results suggest that further development of bisbenzimides for the treatment of pandemic potential poxviruses is warranted.

Impact of an ultrasensitive Cytomegalovirus quantitative nucleic acid test on Cytomegalovirus detection and therapy in renal transplant recipients.

Cytomegalovirus (CMV) infection has broad implications for morbidity and mortality in renal transplant recipients (RTR). Routine surveillance for CMV replication with PCR-based quantitative nucleic acid testing (qNAT) assays is standard practice in most transplant centers, but the impact of assay sensitivity on antiviral decision-making and virologic outcomes has not been studied. We investigated the effects of an ultrasensitive CMV qNAT assay on multiple clinical outcomes, including time to detection and duration of CMV DNAemia. We conducted a single-center cohort study contrasting RTRs monitored with a qNAT with a higher lower limit of quantification (LLOQ >300IU/mL) with those monitored with a more sensitive qNAT (LLOQ >35IU/mL). Patients were stratified by donor (D)/recipient (R) CMV serostatus (D+/R-: high risk; any R+: moderate risk). CMV viral load monitoring was performed monthly post transplantation, with the primary outcomes being time to CMV DNAemia and its duration. Total 1382 patients were analyzed from 2014 to 2016 and 2019 to 2021. Moderate-risk RTRs monitored with the more sensitive assay experienced a greater hazard for the development of a first episode of CMV DNAemia (aHR: 1.95, 95% confidence interval [CI]: 1.55-2.46) and an average of 24 (95% CI: 16.40-31.98) additional days of DNAemia. There was no difference in CMV end-organ disease or 1-year all-cause mortality between moderate-risk RTRs. The more sensitive assay was associated with earlier detection and extended durations of CMV DNAemia in moderate-risk RTRs, without altering clinical outcomes. These findings inform optimal use of these assays and antiviral stewardship in RTRs. The use of ultrasensitive CMV qNAT assays in moderate-risk CMV renal transplant recipients is associated with earlier detection and longer durations of CMV DNAemia without impacting CMV end-organ disease or 1-year mortality.

Inhibition of human cytomegalovirus replication by interferon alpha can involve multiple anti-viral factors.

The shortcomings of current direct-acting anti-viral therapy against human cytomegalovirus (HCMV) has led to interest in host-directed therapy. Here we re-examine the use of interferon proteins to inhibit HCMV replication utilizing both high and low passage strains of HCMV. Pre-treatment of cells with interferon alpha (IFNα) was required for robust and prolonged inhibition of both low and high passage HCMV strains, with no obvious toxicity, and was associated with an increased anti-viral state in HCMV-infected cells. Pre-treatment of cells with IFNα led to poor expression of HCMV immediate-early proteins from both high and low passage strains, which was associated with the presence of the anti-viral factor SUMO-PML. Inhibition of HCMV replication in the presence of IFNα involving ZAP proteins was HCMV strain-dependent, wherein a high passage HCMV strain was obviously restricted by ZAP and a low passage strain was not. This suggested that strain-specific combinations of anti-viral factors were involved in inhibition of HCMV replication in the presence of IFNα. Overall, this work further supports the development of strategies involving IFNα that may be useful to inhibit HCMV replication and highlights the complexity of the anti-viral response to HCMV in the presence of IFNα.

Apheresis for Production of Chimeric Antigen Receptor (CAR) T Cells in Patients with Multiple Myeloma - Clinical Factors, Cell Composition and T Cell Senescence

Chimeric antigen receptor (CAR) T cells have been proven as a highly promising immunotherapy for patients with multiple myeloma (MM). Apheresis of autologous CD3+ lymphocytes is the first pivotal step in the production process of chimeric antigen receptor (CAR) T cells. Repetitive activation of T lymphocytes can affect the qualitative properties, i.e. the fitness of CD3 cells leading to progressive loss of expression of the costimulatory receptors CD27 and CD28. CD3+27-28- cells are non-proliferating memory, senescent cells. In that regard, the factors influencing the manufacturing process of CAR T cells in patients with MM have not been sufficiently explored. We performed a retrospective analysis of clinical parameters influencing both collection of autologous lymphocytes and the subsequent manufacturing of idecabtagene-vicleucel with a special focus on T cell senescence, defined as loss of CD27 and CD28. Furthermore, we focused on cell-compositions of collections resulting in out of specification (OOS) events during CAR T cell manufacturing. Between January 2022 and January 2023, 36 lymphocyte collections of 32 patients with relapsed/refractory (r/r) MM were performed for subsequent CAR T cell therapy with idecabtagene-vicleucel. All collections were forwarded for further manufacturing without prior cryokonservation. 9 (25%) collections resulted in OOS; 7/9 resulting in insufficient proliferation or expansion of T cells, while 2/9 showed a microbial contamination during the manufacturing process after viral transduction for CAR generation. At apheresis, the patients were a median 63 (range 39-75) years old, 12 (38%) were female with median body weight 79 kg (49-103). The patients had a median of 7 previous treatment lines (range 3-13) and 15/36 collections were performed at partial remission or better. 8/36 collection had prior exposition to bispecific antibodies whereas in 13/36 collections the unspecific positivity for cytomegalovirus (CMV) in polymerase chain reaction (PCR) was detected. The collections were performed on a Spectra Optia cell-separator by processing median 3x total blood volume. CD3+ cells in peripheral blood (pB) were median 513.9 /µl (range 70.6-3616.0). The collections showed a median CD3+ yield with 29.8 x10 8 (range 4.9-171.6), with CD3+4+ and CD3+8+ yields 10.6 x10 8 (range 1-663.4) and 16.3 x10 8 (range 3.2-121.2) respectively, resulting in median CD4:CD8 ratio of 0.6 (range 0.1-2.6). The median yields for CD3+27+28+ and CD3+27-28- cells were 14.8 (range 2.3-88.8) x10 8 and 2.1 (range 0.1-59.8) x10 8 respectively. Noteworthy, OOS events were more common in patients with detectable cytomegalovirus replication at apheresis ( P=0.037) with a trend for prior exposition to bispecific antibodies ( P=0.086). In contrast, the collections with OOS did not differ regarding patients' age ( P=0.498), sex ( P=0.442), body weight ( P=0.364), number of previous treatment lines ( P=0.185) or remission status at apheresis ( P=0.443). In OOS collections, CD3+ cells in pB were significantly higher with median 991 /µl (range 558-2968) compared to 448.9 /µl (70.6-3616.0) ( P=0.002) and showed a trend for higher CD3+ yields with 38.9 x10 8 (range 23.9-62.2) and 28.2 x10 8 (range 4.9-171.6) respectively ( P=0.096). Interestingly, OOS products also had higher median yields of CD3+CD8+ cells with 28.1 x10 8 (range 12.2-52.3) compared to 15.3 x10 8 (range 3.2-121.2), ( P=0.046) and showed a trend for lower median CD3+CD4+ yields with 9.1 x10 8 (range 3.8-11.9) compared to 11.4 x10 8 (range 1.6-63.4), ( P=0.071). Median CD3+27+28+ yields in OOS and successful manufacturings were 9.7 x10 8 (4.7-26.0) and 17.0 x10 8(range 2.4-88.8) respectively ( P=0.030). OOS events yielded with higher median CD3+27-28- with 17.8 x10 8(range 0.2-46.1) compared to 1.4 x10 8 (0.1-59.8), ( P=0.031). We observed a negative prognostic role of CMV replication as well as of senescence of T lymphocytes on the manufacturing process. In contrast, a successful manufacturing was not influenced by patient age, sex, remission status at apheresis or number of previous treatment lines. Further analyses are required to determine measures appropriate for further optimization of autologous lymphocyte collections and improvement of collection outcomes in patients with MM.

Real-World Experience With CMV inSIGHT T Cell Immunity Testing in High-Risk Kidney and Pancreas Transplant Recipients.

Cytomegalovirus (CMV)-specific cell-mediated immunity is important for control of CMV after transplant. Assays exist to measure this, but their place in therapy is unclear, particularly in CMV high-risk recipients, without pretransplant exposure. The objective of this study was to evaluate predictive potential of a positive assay to determine freedom from DNAemia and describe subsequent 3-month CMV outcomes. Adult CMV high-risk kidney and/or pancreas transplant recipients were included if a CMV inSIGHT T Cell Immunity Panel (TCIP, Eurofins Viracor) was ordered and resulted between 1 August, 2019 and 30 July, 2022. Seventy-six patients were included in our study; 49 tested during prophylaxis and 27 during treatment. Most TCIP assays obtained in the prophylaxis cohort were negative (n = 46, 93.9%). Rate of post-TCIP CMV infection was 10.2%. In those tested during treatment, 33.3% were positive and rate of post-TCIP CMV recurrence was 22.2%. The positive predictive value of the assay to successfully predict immunity was 66.7% during both prophylaxis and treatment. There were 4 cases of TCIP predictive failure with progressive CMV replication. At time of replication, 2 patients had concomitant clinical confounders thought to influence immune control of viral replication. All patients had intensification of immunosuppression prior to recurrent replication, but after TCIP was collected. The data obtained from the TCIP are not static, immune control of CMV in latency can change and must be evaluated in clinical context. Timing of TCIP after transplant is significant, and patient-specific factors remain important to assess the likelihood of CMV in each unique patient-specific scenario. A CMV stewardship program can aid in application and interpretation of results.

Torque teno virus-DNA load as individual cytomegalovirus risk assessment parameter upon allogeneic hematopoietic stem cell transplantation.

Immune recovery following allogeneic hematopoietic stem cell transplantation (allo-HSCT) decisively influences the occurrence of opportunistic infections, one of the leading causes of death among this group of patients. Yet, today, there are no laboratory parameters mirroring immune function sufficiently. Torque teno virus (TTV) has already proven itself as a functional immune marker in other settings. In this analysis, we investigated whether monitoring of TTV-DNA load in whole blood is able to provide additional information on the capacity of the immune system to control cytomegalovirus (CMV) replication in allo-HSCT recipients. Whole blood samples from 59 patients were collected upon allo-HSCT (between Day -7 and +10), on Day +14, +21, +28, +56, +90, and +365 post-transplant. TTV-DNA loads and other relevant clinical information were correlated with the risk of CMV infections or reactivations, defined by evidence of viral replication in blood. CMV serostatus of the recipient and a TTV load below 1000 copies/mL upon allo-HSCT were significantly associated with an increased incidence of CMV infection or reactivation. Quantification of TTV load in the early phase of allo-HSCT procedure could provide additional information in order to identify patients at risk for CMV infection or reactivation.