T-Cell Immune Responses in Newborns and Long-Term Sequelae in Congenital Cytomegalovirus Infection (CYTRIC Study).

OBJECTIVE: The objective of this study was to assess the role of T-lymphocyte immune responses in newborns with congenital cytomegalovirus (CMV) infection (cCMV) and their potential association with the development of long-term sequelae. STUDY DESIGN: A multicenter, prospective study from 2017 to 2022 was conducted across 8 hospitals in Spain. Blood samples were collected within the first month of life from neonates diagnosed with cCMV. Intracellular cytokine staining was employed to evaluate the presence of CMV-specific interferon-gamma (IFN-γ)-producing CD8+ and CD4+ T lymphocytes (CMV-IFN-γ-CD8+/CD4+) using flow cytometry. The development of sequelae, including hearing loss and neurologic impairment, was assessed during follow-up. RESULTS: In total, 64 newborns were included; 42 infants (65.6%) had symptomatic cCMV. The median age at the last follow-up visit was 25.3 months (IQR 20.1-34.4). Eighteen infants had long-term sequelae (28.1%), predominantly hearing loss (20.3%) and neurologic disorders (15.6%). No relationship was observed between total count or percentage of CMV-specific IFN-γ-CD8+ or CD4+ lymphocytes and long-term sequelae. Multivariable analysis demonstrated an association between lower total lymphocyte count and long-term sequelae (aOR 0.549, 95% CI: 0.323-0.833), which requires further study. CONCLUSIONS: CMV-specific IFN-γ-CD4+ and CD8+ T-lymphocyte responses in neonates with cCMV were not predictive of long-term sequelae.

Letermovir use may impact on the Cytomegalovirus DNA fragmentation profile in plasma from allogeneic hematopoietic stem cell transplant recipients.

Cytomegalovirus (CMV) DNA in plasma is mainly unprotected and highly fragmented. The size of the amplicon largely explains the variation in CMV DNA loads quantified across PCR platforms. In this proof-of-concept study, we assessed whether the CMV DNA fragmentation profile may vary across allogeneic hematopoietic stem cell transplant recipients (allo-SCT), within the same patient over time, or is affected by letermovir (LMV) use. A total of 52 plasma specimens from 14 nonconsecutive allo-SCT recipients were included. The RealTime CMV PCR (Abbott Molecular), was used to monitor CMV DNA load in plasma, and fragmentation was assessed with a laboratory-designed PCR generating overlapping amplicons (around 90-110 bp) within the CMV UL34, UL80.5, and UL54 genes. Intrapatient, inter-patient, and LMV-associated qualitative and quantitative variations in seven amplicons were observed. These variations were seemingly unrelated to the CMV DNA loads measured by the Abbott PCR assay. CMV DNA loads quantified by UL34_4, UL54.5, and UL80.5_1 PCR assays discriminate between LMV and non-LMV patients. Our observations may have relevant implications in the management of active CMV infection in allo-SCT recipients, either treated or not with LMV, although the data need further validation.

SARS-CoV-2-Spike T-cell response after receiving one or two Wuhan-Hu-1-based mRNA COVID-19 vaccine booster doses in elderly nursing home residents.

The effect of COVID-19 booster vaccination on SARS-CoV-2 T-cell mediated immune responses in elderly nursing home residents has not been explored in depth. Thirty-nine elderly nursing home residents (median age, 91 years) were included, all fully vaccinated with mRNA vaccines. The frequency of and the integrated mean fluorescence (iMFI) for peripheral blood SARS-CoV-2-Spike reactive IFN-γ-producing CD4+ or CD8+ T cells before and after the first (Pre-3D and Post-3D) and second (Pre-4D and Post-4D) vaccine booster doses was determined using flow cytometry for an intracellular staining method. 3D increased significantly (p = 0.01) the percentage of participants displaying detectable SARS-CoV-2-T-cell responses compared with pre-3D (97% vs. 74%). The magnitude of the increase was statistically significant for CD8+ T cells (p = 0.007) but not for CD4+ T cells (p = 0.77). A trend towards higher frequencies of peripheral blood SARS-CoV-2-CD8+ T cells was observed post-3D compared with pre-3D (p = 0.06). The percentage of participants with detectable SARS-S-CoV-2 CD4+ T-cell responses decreased post-4D (p = 0.035). Following 4D, a nonsignificant decrease in the frequencies of both T cell subsets was noticed (p = 0.94 for CD8+ T cells and p = 0.06 for CD4+ T cells). iMFI data mirrored that of T-cell frequencies. The kinetics of SARS-CoV-2 CD8+ and CD4+ T cells following receipt of 3D and 4D were comparable across SARS-CoV-2-experienced and -naïve participants and between individuals receiving a homologous or heterologous vaccine booster. 3D increased the percentage of elderly nursing home residents displaying detectable SARS-CoV-2 T-cell responses but had a marginal effect on T-cell frequencies. The impact of 4D on SARS-CoV-2 T-cell responses was negligible; whether this was due to suboptimal priming or rapid waning could not be ascertained.

Abbott realtime MTB assay for detecting Mycobacterium tuberculosis complex in respiratory specimens: a cost-benefit analysis.

PURPOSE: Molecular screening for Mycobacterium tuberculosis (MTB) can lead to rapid empirical treatment inception and reduce hospitalization time and complementary diagnostic tests. However, in low-prevalence settings, the cost-benefit balance remains controversial due to the high cost. METHODS: We used a Markov model to perform an economic analysis to evaluate the profit after implementing molecular MTB screening (Period B) compared with conventional culture testing (Period A) in respiratory samples from 7,452 consecutive subjects with presumed tuberculosis (TB). RESULTS: The proportion of positivity was comparable between both periods (P > 0.05), with a total of 2.16 and 1.78 samples/patient requested in periods A and B, respectively (P < 0.001). The mean length of hospital stay was 8.66 days (95%CI: 7.63-9.70) in Period B and 11.51 days (95%CI: 10.15-12.87) in Period A (P = 0.001). The healthcare costs associated with diagnosing patients with presumed TB were reduced by €717.95 per patient with PCR screening. The probability of remaining hospitalized and the need for a greater number of outpatient specialty care visits were the variables with the most weight in the model. CONCLUSION: Employing PCR as an MTB screening method in a low-prevalence setting may increase the profits to the system.

Performance of the Roche Elecsys® IGRA SARS-CoV-2 test for the detection and quantification of virus-reactive T cells in COVID-19-vaccinated immunosuppressed patients and healthy subjects.

PURPOSE: Comparing the performance of commercially available SARS-CoV-2 T-cell immunoassay responses may provide useful information for future observational or intervention studies as well as to their potential customers. METHOD: Whole blood was collected from a total of 183 subjects fully vaccinated against COVID-19: 55 healthy controls (Group 1), 50 hematological patients (Group 2), 50 chronic kidney disease patients (Group 3), and 28 elderly nursing home residents (Group 4). Samples were tested with the Roche Elecsys® IGRA (Interferon-gamma release assay) SARS-CoV-2 test (Roche Diagnostics, Rotkreuz, Switzerland), the Euroimmun SARS-CoV-2 test (Euroimmun, Lubeck, Germany), the SARS-CoV-2 T Cell Analysis Kit (Miltenyi Biotec, Bergisch Gladbach, Germany), and a flow-cytometry for intracellular cytokine (IFN-γ) staining-based immunoassay (FC-ICS). RESULTS: Overall, the Roche Elecsys® assay returned the highest number of positive results (151/179; 84.3%), followed by the Euroimmun test (127/183; 69%), and the FC-ICS (135/179; 75%). The Kappa coefficient of agreement was best between IGRAs (0.64). Most discordant results across assays involved patients from Group 2. Overall, IFN-γ concentrations measured by both IGRAs correlated strongly (rho = 0.78; 95% CI 0.71-0.84; P < 0.001) irrespective of the study group. The frequencies of SARS-CoV-2-reactive IFN-γ T cells and IFN-γ concentrations measured by the IGRAs correlated moderately for CD4+ T cells, however, weakly for CD8+ T cells. SARS-CoV-2-experienced participants displayed stronger responses than SARS-CoV-2-naïve when IGRAs, rather than FC-ICS, were used. CONCLUSION: The SARS-CoV-2 immunoassays evaluated in the present study did not return interchangeable qualitative or quantitative results either in seemingly healthy individuals or in immunosuppressed patients.

Genotypic study of Chlamydia trachomatis for lymphogranuloma venereum diagnosis in rectal specimens from men who have sex with men: a cost-effectiveness analysis.

PURPOSE: The significant proportion of asymptomatic patients and the scarcity of genotypic analysis of lymphogranuloma venereum (LGV), mainly among men who have sex with men (MSM), triggers a high incidence of underdiagnosed patients, highlighting the importance of determining the most appropriate strategy for LGV diagnosis, at both clinical and economical levels. MATERIALS AND METHODS: We conducted L1-L3 serovar detection by molecular biology in stored Chlamydia trachomatis-positive samples from MSM patients with HIV, another STI or belonging to a Pre-exposure prophylaxis program, to make a cost effectiveness study of four diagnostic strategies with a clinical, molecular, or mixed approach. RESULTS: A total of 85 exudates were analyzed: 35urethral (31 symptomatic/4 positive) and 50 rectal (22 symptomatic/25 positive), 70/85 belonging to MSM with associated risk factors. The average cost per patient was €77.09 and €159.55 for clinical (Strategy I) and molecular (Strategy IV) strategies respectively. For molecular diagnosis by genotyping of all rectal exudate samples previously positive for CT (Strategy II), the cost was €123.84. For molecular diagnosis by genotyping of rectal and/or urethral exudate samples from all symptomatic patients (proctitis or urethritis) with a previous positive result for CT (Strategy III), the cost was €129.39. The effectiveness ratios were 0.80, 0.95, 0.91, and 1.00 for each strategy respectively. The smallest ICER was €311.67 for Strategy II compared to Strategy I. CONCLUSIONS: With 30% asymptomatic patients, the most cost-effective strategy was based on genotyping all rectal exudates. With less restrictive selection criteria, thus increasing the number of patients with negative results, the most sensitive strategies tend to be the most cost-effective, but with a high incremental cost-effectiveness ratio.

Multiplexable and Biocomputational Virus Detection by CRISPR-Cas9-Mediated Strand Displacement.

Recurrent disease outbreaks caused by different viruses, including the novel respiratory virus SARS-CoV-2, are challenging our society at a global scale; so versatile virus detection methods would enable a calculated and faster response. Here, we present a novel nucleic acid detection strategy based on CRISPR-Cas9, whose mode of action relies on strand displacement rather than on collateral catalysis, using the Streptococcus pyogenes Cas9 nuclease. Given a preamplification process, a suitable molecular beacon interacts with the ternary CRISPR complex upon targeting to produce a fluorescent signal. We show that SARS-CoV-2 DNA amplicons generated from patient samples can be detected with CRISPR-Cas9. We also show that CRISPR-Cas9 allows the simultaneous detection of different DNA amplicons with the same nuclease, either to detect different SARS-CoV-2 regions or different respiratory viruses. Furthermore, we demonstrate that engineered DNA logic circuits can process different SARS-CoV-2 signals detected by the CRISPR complexes. Collectively, this CRISPR-Cas9 R-loop usage for the molecular beacon opening (COLUMBO) platform allows a multiplexed detection in a single tube, complements the existing CRISPR-based methods, and displays diagnostic and biocomputing potential.

Evaluation of a Quantitative Dual-Target EBV DNA Test on a Fully Automated Molecular Testing System.

The measurement of Epstein-Barr virus (EBV) deoxyribonucleic acid (DNA) is key to diagnosing and managing EBV-associated complications in transplant recipients. The performance of the new Conformité Européenne (CE) and Food and Drug Administration (FDA)-cleared quantitative Roche cobas EBV real-time PCR assay was determined by using EDTA-plasma dilution panels and clinical samples that were spiked with either the World Health Organization's EBV international standard or high-titer EBV lambda stock. Correlation with the Abbott Realtime EBV assay was assessed in clinical specimens and conducted at two independent laboratories. An in silico analysis revealed that the dual-target test (EBNA1 and BMRF2) was 100% inclusive for the known diversity of EBV. The overall limit of detection (LoD) was 16.6 IU/mL for genotype 1 (GT1). GT2 LoD was verified at 18.8 IU/mL. The linear ranges were from 1.40 × 101 to 2.30 × 108 IU/mL and from 2.97 × 101 to 9.90 × 107 IU/mL for GT1 and GT2, respectively. Accuracy was confirmed across the linear range (mean difference not exceeding ±0.18 log10). Precision was not influenced by the factors analyzed (standard deviation of 0.02 to 0.17 log10), including the presence of potentially interfering endogenous or exogenous substances. Plasma samples were stable under several conditions (variable time points, storage, and freeze/thaw cycles). In clinical EBV DNA-positive samples, correlation between the cobas EBV test and the comparator was high (n = 126 valid results; R2 = 0.96) with a 0.1 mean log10 titer difference. The cobas EBV test is an accurate, sensitive, specific, and reproducible assay for the detection of EBV DNAemia in plasma. In general, high levels of automation and calibration to the international standard will lead to improvements in the harmonization of quantitative EBV DNA test results across laboratories.

Multi-site performance evaluation of the Alinity m Molecular assay for quantifying Epstein-Barr virus DNA in plasma samples.

Detection and monitoring of acute infection or reactivation of Epstein-Barr virus (EBV) are critical for treatment decision-making and to reduce the risk of EBV-related malignancies and other associated diseases in immunocompromised individuals. The analytical and clinical performance of the Alinity m EBV assay was evaluated at two independent study sites; analytical performance was assessed by evaluating precision with a commercially available 5-member EBV verification panel, while the clinical performance of the Alinity m EBV assay was compared to the RealTime EBV assay and a laboratory-developed test (LDT) as the routine test of record (TOR). Analytical analysis demonstrated standard deviation (SD) between 0.08 and 0.13 Log IU/mL. A total of 300 remnant plasma specimens were retested with the Alinity m EBV assay, and results were compared to those of the TOR at the respective study sites (n = 148 with the RealTime EBV assay and n = 152 with the LDT EBV assay). Agreement between Alinity m EBV and RealTime EBV or LDT EBV assays had kappa values of 0.88 and 0.84, respectively, with correlation coefficients r of 0.956 and 0.912, while the corresponding observed mean bias was -0.02 and -0.19 Log IU/mL. The Alinity m EBV assay had a short median onboard turnaround time of 2:40 h. Thus, the Alinity m system can shorten the time to results and, therefore, to therapy.

Multicenter performance evaluation of the Alinity m CMV assay for quantifying cytomegalovirus DNA in plasma samples.

Monitoring of cytomegalovirus (CMV) viral load is critical for informing treatment decisions in order to prevent the severe health consequences of CMV infection or reactivation of latent CMV in immunocompromised individuals. This first field evaluation examined the analytical and clinical performance of the Alinity m CMV assay. Analytical performance was assessed with a commercially available six-member panel, while the clinical performance evaluation compared the Alinity m CMV assay to the RealTime CMV assay and a laboratory-developed test (LDT) as the test of record at three large hospital-based clinical laboratories. Precision of the Alinity m CMV assay was demonstrated with total standard deviation (SD) between 0.08 and 0.28 Log IU/mL. A total of 457 plasma specimens were tested on the Alinity m CMV assay and compared to the test of record at each site (n = 304 with RealTime CMV and n = 153 with LDT CMV). The Alinity m CMV assay had excellent correlation (correlation coefficient r ≥0.942) in comparison to the RealTime CMV or LDT CMV assays. The mean observed bias ranged from -0.03 to 0.34 Log IU/mL. Median onboard turnaround time of Alinity m CMV was less than 3 h. When the CMV assay is run on the Alinity m system, it has the capacity to shorten time to result and, therefore, to therapy.

Immunovirology of cytomegalovirus infection in allogeneic stem cell transplant recipients undergoing prophylaxis with letermovir: A narrative review.

On November 7, 2017, the US Food and Drug Administration approved the use of letermovir (LMV) for prophylaxis of cytomegalovirus (CMV) infection in adult CMV-seropositive allogeneic stem cell transplant recipients. After 6 years of use, a large body of real-world experience has been accumulated that validates the Phase III clinical trial results, in which LMV was shown to significantly reduce the risk of clinically significant CMV infection-defined as CMV end-organ disease or CMV DNAemia requiring pre-emptive antiviral therapy (PET)-and increase survival up to Week 24 after treatment inception. Notwithstanding, several issues still need to be settled, thus further investigation is required. First, since viral DNA may accumulate as a result of LMV-driven abortive CMV infection, what is the optimal viral load threshold in the blood that would prompt LMV prophylaxis interruption and PET inception? Should this be adapted to the patient's risk? Second, what is the impact of LMV prophylaxis on the reconstitution of functional CMV-specific T-cell responses? Would it be a wise approach to individually tailor the duration of LMV treatment according to the number of peripheral blood CMV-specific T cells at the end of regular prophylaxis? Third, how frequently do LMV-resistant strains arise while patients are on LMV prophylaxis and how could this be minimized? Here, we discuss the literature addressing these topics.

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.

A performance comparison of two (electro) chemiluminescence immunoassays for detection and quantitation of serum anti-spike antibodies according to SARS-CoV-2 vaccination and infections status.

The information provided by SARS-CoV-2 spike (S)-targeting immunoassays can be instrumental in clinical-decision making. We compared the performance of the Elecsys® Anti-SARS-CoV-2 S assay (Roche Diagnostics) and the LIAISON® SARS-CoV-2 TrimericS IgG assay (DiaSorin) using a total of 1176 sera from 797 individuals, of which 286 were from vaccinated-SARS-CoV-2/experienced (Vac-Ex), 581 from vaccinated/naïve (Vac-N), 147 from unvaccinated/experienced (Unvac-Ex), and 162 from unvaccinated/naïve (Unvac-N) individuals. The Roche assay returned a higher number of positive results (907 vs. 790; p = 0.45; overall sensitivity: 89.3% vs. 77.6%). The concordance between results provided by the two immunoassays was higher for sera from Vac-N (Ï°: 0.58; interquartile ranges [IQR]: 0.50-0.65) than for sera from Vac-Ex (Ï°: 0.19; IQR: -0.14 to 0.52) or Unvac-Ex (Ï°: 0.18; IQR: 0.06-0.30). Discordant results occurred more frequently among sera from Unvac-Ex (34.7%) followed by Vac-N (14.6%) and Vac-Ex (2.7%). Antibody levels quantified by both immunoassays were not significantly different when <250 (p = 0.87) or <1000 BAU/ml (p = 0.13); in contrast, for sera ≥1000 BAU/ml, the Roche assay returned significantly higher values than the DiaSorin assay (p < 0.008). Neutralizing antibody titers (NtAb) were measured in 127 sera from Vac-Ex or Vac-N using a S-pseudotyped virus neutralization assay of Wuhan-Hu-1, Omicron BA.1, and Omicron BA.2. The correlation between antibody levels and NtAb titers was higher for sera from Vac-N than those from Vac-Ex, irrespective of the (sub)variant considered. In conclusion, neither qualitative nor quantitative results returned by both immunoassays are interchangeable. The performance of both assays was found to be greatly influenced by the vaccination and SARS-CoV-2 infection status of individuals.

Antibody-dependent NK-cell and neutralizing antibody responses against the Spike protein of Wuhan-Hu-1 and Omicron BA.1 SARS-CoV-2 variants in vaccinated experienced and vaccinated naïve individuals.

Antibodies triggering Fc-mediated NK cell activity may contribute to protection against disease caused by SARS-CoV-2 infection in humans. However, how these Fc-mediated humoral responses compare between individuals displaying hybrid immunity (Vac-ex) and those fully vaccinated with no history of SARS-CoV-2 infection (Vac-n) and whether they correlate with neutralizing antibody (NtAb) responses remains largely undetermined. In this retrospective study serum samples from 50 individuals (median age, 44.5 years; range, 11-85; 25 males), 25 Vac-ex and 25 Vac-n were studied. A flow-cytometry-based antibody-mediated NK-cell activation assay was used to quantitate effector NK-cells stimulated to express LAMP1 (lysosomal associated membrane protein 1), MIP1 (Macrophage inflammatory protein 1), and interferon-γ (IFNγ); NK cells isolated from two donors (D1 and D2) were used. NtAb levels targeting the Spike protein of Wuhan-Hu-1 and Omicron BA.1 SARS-CoV-2 variants were quantitated using a SARS-CoV-2 S pseudotyped neutralization assay. Regardless of the SARS-CoV-2 variant S antigen used in the NK-cell activation assay, the frequency of NK cells stimulated to express LAMP-1, MIP1ß, and IFNγ was higher in Vac-ex compared with Vac-n (p values ranging from 0.07 to 0.006) for D1; this was only seen for BA.1 when NK cells from D2 were employed. The frequency of functional NK cells activated by antibody binding to either Wuhan-Hu-1 or Omicron BA.1 S protein was not significantly different for both VAC-ex and VAC-n. In contrast, NtAb titers against BA.1 were around 10-fold lower than that against Wuhan-Hu-1. Vac-ex displayed higher NtAb titers against both (sub)variants than Vac-n. NK-cell responses correlated poorly with NtAb titers (ρ ≤ 0.30). The data demonstrate higher cross-reactivity across variants of concern for antibodies triggering Fc-mediated NK cell than for NtAb. Moreover, Vac-Ex seemed to display more robust functional antibody responses as compared with Vac-n.

A machine learning model for predicting serum neutralizing activity against Omicron SARS-CoV-2 BA.2 and BA.4/5 sublineages in the general population.

Supervised machine learning (ML) methods have been used to predict antibody responses elicited by COVID-19 vaccines in a variety of clinical settings. Here, we explored the reliability of a ML approach to predict the presence of detectable neutralizing antibody responses (NtAb) against Omicron BA.2 and BA.4/5 sublineages in the general population. Anti-SARS-CoV-2 receptor-binding domain (RBD) total antibodies were measured by the Elecsys® Anti-SARS-CoV-2 S assay (Roche Diagnostics) in all participants. NtAbs against Omicron BA.2 and BA4/5 were measured using a SARS-CoV-2 S pseudotyped neutralization assay in 100 randomly selected sera. A ML model was built using the variables of age, vaccination (number of doses) and SARS-CoV-2 infection status. The model was trained in a cohort (TC) comprising 931 participants and validated in an external cohort (VC) including 787 individuals. Receiver operating characteristics analysis indicated that an anti-SARS-CoV-2 RBD total antibody threshold of 2300 BAU/mL best discriminated between participants either exhibiting or not detectable Omicron BA.2 and Omicron BA.4/5-Spike targeted NtAb responses (87% and 84% precision, respectively). The ML model correctly classified 88% (793/901) of participants in the TC: 717/749 (95.7%) of those displaying ≥2300 BAU/mL and 76/152 (50%) of those exhibiting antibody levels <2300 BAU/mL. The model performed better in vaccinated participants, either with or without prior SARS-CoV-2 infection. The overall accuracy of the ML model in the VC was comparable. Our ML model, based upon a few easily collected parameters for predicting neutralizing activity against Omicron BA.2 and BA.4/5 (sub)variants circumvents the need to perform not only neutralization assays, but also anti-S serological tests, thus potentially saving costs in the setting of large seroprevalence studies.

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.

Cumulative incidence of SARS-CoV-2 infection in the general population of the Valencian Community (Spain) after the surge of the Omicron BA.1 variant.

Studies investigating the cumulative incidence of and immune status against SARS-CoV-2 infection provide valuable information for shaping public health decision-making. A cross-sectional study on 935 participants, conducted in the Valencian Community (VC), measuring anti-SARS-CoV-2-receptor binding domain-RBD-total antibodies and anti-Nucleocapsid (N)-IgGs via electrochemiluminescence assays. Quantitation of neutralizing antibodies (NtAb) against ancestral and Omicron BA.1 and BA.2 variants and enumeration of SARS-CoV-2-S specific-IFNγ-producing CD4+ and CD8+ T cells was performed in 100 and 137 participants, respectively. The weighted cumulative incidence was 51.9% (95% confidence interval [CI]: 48.7-55.1) and was inversely related to age. Anti-RBD total antibodies were detected in 97% of participants; vaccinated and SARS-CoV-2-experienced (VAC-ex; n = 442) presented higher levels (p < 0.001) than vaccinated/naïve (VAC-n; n = 472) and nonvaccinated/experienced (UNVAC-ex; n = 63) subjects. Antibody levels correlated inversely with time elapsed since last vaccine dose in VAC-n (Rho, -0.52; p < 0.001) but not in VAC-ex (rho -0.02; p = 0.57). Heterologous booster shots resulted in increased anti-RBD antibody levels compared with homologous schedules in VAC-n, but not in VAC-ex. NtAbs against Omicron BA.1 were detected in 94%, 75%, and 50% of VAC-ex, VAC-n and UNVAC-ex groups, respectively. For Omicron BA.2, the figures were 97%, 84%, and 40%, respectively. SARS-CoV-2-S-reactive IFN-γ T cells were detected in 73%, 75%, and 64% of VAC-ex, VAC-n and UNVAC-ex, respectively. Median frequencies for both T-cell subsets were comparable across groups. In summary, by April 2022, around half of the VC population had been infected with SARS-CoV-2 and, due to extensive vaccination, displayed hybrid immunity.

Features of cytomegalovirus DNAemia and virus-specific T-cell responses in allogeneic hematopoietic stem-cell transplant recipients during prophylaxis with letermovir.

BACKGROUND: There is scarce information on the natural kinetics of cytomegalovirus (CMV) DNAemia and dynamics of CMV-specific T-cell reconstitution in allogeneic hematopoietic transplant recipients (allo-HSCT) undergoing letermovir (LMV) prophylaxis. METHODS: Twelve adult CMV-seropositive high-risk recipients (median age, 53 years; 9 males/3 females) undergoing LMV prophylaxis and 13 non-LMV allo-HSCT controls (median age, 58 years; 7 males/6 females) were included. CMV DNAemia in plasma was monitored by real-time polymerase chain reaction. Preemptive antiviral therapy (PET) was administered upon detection of ≥1500 IU/ml. CMV-specific interferon-gamma (IFN-γ)-producing CD8+ and CD4+ T cells were enumerated by flow cytometry around days +30, +60, and +90 after allo-HSCT. Ex vivo experiments assessing of the potential effect of LMV on CMV-specific T-cell expansion in a single CMV-seropositive donor were also conducted. RESULTS: Five LMV patients (41.6%) developed CMV DNAemia that cleared spontaneously. Four patients (33.3%) developed CMV DNAemia after LMV cessation, of which two required PET. Nine non-LMV patients (69.2%) developed CMV DNAemia (five required PET). The percentage of LMV and non-LMV patients exhibiting detectable CMV-specific T-cell responses was comparable (7/10 vs. 10/13; p = .71). Nevertheless, median CMV-specific CD4+ and CD8+ T-cell counts were lower in LMV patients by days +60 (p = .006 and .02, respectively) and +90 (p = .08 and .02). Ex vivo, CMV-specific CD8+ T cells expanded to the same level either in the presence (19.8%) or in the absence of LMV (20.6%). CONCLUSIONS: In our series, episodes of CMV DNAemia in LMV patients cleared spontaneously. A diminished degree of CMV-specific T-cell reconstitution in LMV patients compared to non-LMV patients was observed.

Impact of cytomegalovirus immunodominant HLA-I donor-recipient matching on the incidence and features of virus DNAemia and virus-specific T-cell immune reconstitution in unmanipulated haploidentical hematopoietic stem cell transplantation.

BACKGROUND: We investigated whether donor-recipient mismatch involving one or more cytomegalovirus (CMV) immunodominant (ID) human leukocyte antigen (HLA)-I alleles may impact on the degree of CMV pp65/immediate-early 1 (IE-1) T-cell reconstitution and the incidence of CMV DNAemia in patients undergoing unmanipulated haploidentical hematopoietic stem cell transplantation with high-dose posttransplant cyclophosphamide (PT/Cy-haplo). METHODS: Multicenter observational study including 106 consecutive adult PT/Cy-haplo patients (34 CMV ID HLA-I matched and 72 mismatched). A real-time PCR was used for plasma CMV DNA load monitoring. Enumeration of CMV-specific (pp65/IE-1) interferon (IFN)-γ-producing T cells from several patients was performed by flow cytometry by days +30, +60, +90 and +180 after transplantation. RESULTS: The cumulative incidence of CMV DNAemia, clinically significant CMV DNAemia episodes (cs-CMVi), and recurrent CMV DNAemia was comparable across CMV ID HLA-I matched and mismatched patients (71.8% vs. 80.9%, p = .95; 40.7% vs. 44.2%, p = .85; 16.4% vs. 28.1%; p = .43, respectively). The percentage of patients exhibiting detectable CMV-specific IFN-γ-producing T-cell responses (either CD8+ or CD4+ ) was similar across groups; nevertheless, significantly higher CMV-specific CD8+ T-cell counts were enumerated in the CMV ID HLA-I matched compared to mismatched patients by day +60 (p = .04) and +180 (p = .016) after transplantation. CONCLUSION: CMV ID HLA-I matching may impact on the magnitude of CMV-pp65/IE-1-specific CD8+ T-cell reconstitution; yet, this effect seemed not to have an impact on the incidence of initial, recurrent CMV DNAemia, or cs-CMVi.

Severe Acute Respiratory Syndrome Coronavirus 2 Adaptive Immunity in Nursing Home Residents Following a Third Dose of the Comirnaty Coronavirus Disease 2019 Vaccine.

A third Comirnaty vaccine dose increased severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) receptor-binding domain antibody levels (median, 93-fold) and neutralizing antibody titers against Wuhan-Hu-1 (median, 57-fold), Beta (me 22-fold), Delta, (median, 43-fold), and Omicron (median, 8-fold) variants, but had less impact on S-reactive T-cell immunity in nursing home residents.