Comparison of the artus Epstein–Barr virus (EBV) PCR kit and the Abbott RealTime EBV assay for measuring plasma EBV DNA loads in allogeneic stem cell transplant recipients

Evaluation of two automated real-time PCR-based quantification methods for whole blood Epstein-Barr viral load

Quantification of EBV DNA is important in transplantation settings for the diagnosis of post-transplantation. We evaluated the performance of the AltoStar® EBV PCR Kit 1.5 on whole blood specimens: limit of detection, linearity, accuracy, and precision were determined using the WHO NIBSC 09/260 international standard. Results of 69 clinical samples were compared between the AltoStar® EBV PCR Kit 1.5 (altona Diagnostics) and the RealTime EBV assay (Abbott). The LoD of the AltoStar® Kit was 148 IU/mL and linearity was between 375 and 500000. A high concordance was found between nominal value of the NIBSC dilutions and the AltoStar EBV result. The total variation ranged from 2.2% to 9.6%. Out of 69 clinical samples tested, there was a high concordance between the 22 paired results within the overlapping linear ranges of both tests. The AltoStar® EBV assay is reliable and accurate for EBV viral load determination on whole blood samples.

The IPTA Nashville Consensus Conference on Post-Transplant lymphoproliferative disorders after solid organ transplantation in children: III - Consensus guidelines for Epstein-Barr virus load and other biomarker monitoring

The International Pediatric Transplant Association convened an expert consensus conference to assess current evidence and develop recommendations for various aspects of care relating to post-transplant lymphoproliferative disorders after solid organ transplantation in children. In this report from the Viral Load and Biomarker Monitoring Working Group, we reviewed the existing literature regarding the role of Epstein-Barr viral load and other biomarkers in peripheral blood for predicting the development of PTLD, for PTLD diagnosis, and for monitoring of response to treatment. Key recommendations from the group highlighted the strong recommendation for use of the term EBV DNAemia instead of "viremia" to describe EBV DNA levels in peripheral blood as well as concerns with comparison of EBV DNAemia measurement results performed at different institutions even when tests are calibrated using the WHO international standard. The working group concluded that either whole blood or plasma could be used as matrices for EBV DNA measurement; optimal specimen type may be clinical context dependent. Whole blood testing has some advantages for surveillance to inform pre-emptive interventions while plasma testing may be preferred in the setting of clinical symptoms and treatment monitoring. However, EBV DNAemia testing alone was not recommended for PTLD diagnosis. Quantitative EBV DNAemia surveillance to identify patients at risk for PTLD and to inform pre-emptive interventions in patients who are EBV seronegative pre-transplant was recommended. In contrast, with the exception of intestinal transplant recipients or those with recent primary EBV infection prior to SOT, surveillance was not recommended in pediatric SOT recipients EBV seropositive pre-transplant. Implications of viral load kinetic parameters including peak load and viral set point on pre-emptive PTLD prevention monitoring algorithms were discussed. Use of additional markers, including measurements of EBV specific cell mediated immunity was discussed but not recommended though the importance of obtaining additional data from prospective multicenter studies was highlighted as a key research priority.

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.

A phase I/II dose-escalation multi-center study to evaluate the safety of infusion of natural killer cells or memory T cells as adoptive therapy in coronavirus pneumonia and/or lymphopenia: RELEASE study protocol

BACKGROUND

Moderate/severe cases of COVID-19 present a dysregulated immune system with T cell lymphopenia and a hyper-inflammatory state. This is a study protocol of an open-label, multi-center, double-arm, randomized, dose-finding phase I/II clinical trial to evaluate the safety, tolerability, alloreactivity, and efficacy of the administration of allogeneic memory T cells and natural killer (NK) cells in COVID-19 patients with lymphopenia and/or pneumonia. The aim of the study is to determine the safety and the efficacy of the recommended phase 2 dose (RP2D) of this treatment for patients with moderate/severe COVID-19.

METHODS

In the phase I trial, 18 patients with COVID-19-related pneumonia and/or lymphopenia with no oxygen requirement or with an oxygen need of ≤ 2.5 liters per minute (lpm) in nasal cannula will be assigned to two arms, based on the biology of the donor and the patient. Treatment of arm A consists of the administration of escalating doses of memory T cells, plus standard of care (SoC). Treatment of arm B consists of the administration of escalating doses of NK cells, plus SoC. In the phase II trial, a total of 182 patients with COVID-19-related pneumonia and/or lymphopenia requiring or not oxygen supplementation but without mechanical ventilation will be allocated to arm A or B, considering HLA typing. Within each arm, they will be randomized in a 1:1 ratio. In arm A, patients will receive SoC or RP2D for memory T cells plus the SoC. In arm B, patients will receive SoC or RP2D for NK cells plus the SoC.

DISCUSSION

We hypothesized that SARS-CoV-2-specific memory T-lymphocytes obtained from convalescent donors recovered from COVID-19 can be used as a passive cell immunotherapy to treat pneumonia and lymphopenia in moderate/severe patients. The lymphopenia induced by COVID-19 constitutes a therapeutic window that may facilitate donor engraftment and viral protection until recovery.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04578210 . First Posted : October 8, 2020.

A New Clinical and Immunovirological Score for Predicting the Risk of Late Severe Infection in Solid Organ Transplant Recipients: The CLIV Score

BACKGROUND

We aimed at constructing a composite score based on Epstein-Barr virus DNAemia (EBVd) and simple clinical and immunological parameters to predict late severe infection (LI) beyond month 6 in solid organ transplantation (SOT) recipients.

METHODS

Kidney and liver transplant recipients between May 2014 and August 2016 at 4 participating centers were included. Serum immunoglobulins and complement factors, peripheral blood lymphocyte subpopulations, and whole blood EBVd were determined at months 1, 3, and 6. Cox regression analyses were performed to generate a weighted score for the prediction of LI.

RESULTS

Overall, 309 SOT recipients were followed-up for a median of 1000 days from transplant (interquartile range, 822-1124). Late severe infection occurred in 104 patients (33.6%). The CLIV Score consisted of the following variables at month 6: high-level EBVd (>1500 IU/mL) and recurrent infection during the previous months (6 points); recipient age ≥70 years and chronic graft dysfunction (5 points); cytomegalovirus mismatch (4 points); and CD8+ T-cell count <400 cells/μL (2 points). The area under receiver operating characteristics curve was 0.77 (95% confidence interval, 0.71-0.84). The risk of LI at day 1000 was as follows: score 0, 12.6%; score 2-5, 25.5%; score 6-9, 52.7%; score ≥10, 73.5%.

CONCLUSIONS

While waiting for further external validation, the CLIV Score based on clinical and immune-virological parameters is potentially useful to stratify the risk of LI after SOT.

Automated quantification of Epstein-Barr virus in whole blood for post-transplant lymphoproliferative disorders monitoring

Background

Standardized and sensitive assays for Epstein Barr Virus (EBV) are needed to define universal cutoff for treatment initiation in allogeneic hematopoietic stem cells transplant recipients. In a context of accreditation and the availability of EBV international standard, we evaluated the Abbott RealTime EBV (RT) assay for EBV quantification in whole blood.

Methods

The RT assay was compared on 282 prospective clinical samples with the Artus EBV PCR Kit V1 assay (V1) and we analyzed the kinetics of EBV load in 11 patients receiving rituximab treatment.

Results

The estimated limit of detection was 88 IU/mL. The assay was linear (r² = 0.9974) in the range of all samples tested (100 to 1,000,000 IU/mL). Intra-assay coefficients of variation (CV) ranged between 0.35 and 1.35%, and inter-assay CV between 3.40 and 4.5%. On samples above the limit of quantification, the two assays were strongly correlated. EBV RT values were on average 0.30 log₁₀ IU/mL lower than those measured with the V1 assay. In patients treated with rituximab, the RT assay remained positive in 5 patients at the time it dropped below undetectable levels with the V1 assay.

Conclusions

In conclusion, the RT assay is a reliable assay for EBV load in whole blood. Its sensitivity will enable to estimate the kinetics of EBV load and the impact of treatments to control EBV reactivations.

Evaluation of the Abbott RealTime quantitative CMV and EBV assays using the maxCycle protocol in a laboratory automation context

Real-time PCR are often used for the diagnosis and monitoring of Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infections in susceptible populations. In this context, we evaluated the analytical performances of the Abbott RealTime CMV/EBV maxCycle protocol automated on the m2000 platform (Abbott). It was compared to our routinely-used procedure consisting of a NucleoMag® DNA extraction automated on a STARlet platform followed by manually processed CMV and EBV quantitative real-time PCR (Diagenode). In this study, we showed that both EBV assays exhibited a similar sensitivity but with a better precision for the EBV Abbott RealTime assay. For the CMV performances, the Abbott assay was more sensitive and more precise than our routine method. The use of WHO International Standards also indicated a slight underestimation of the viral loads (-0.25 log₁₀ IU/mL and -0.21 log₁₀ IU/mL for CMV and EBV assays respectively) while these were rather overestimated with the Starlet/Diagenode method (0.48 log₁₀ IU/mL and 0.19 log₁₀ IU/mL for CMV and EBV assays respectively). These trends were confirmed using relevant whole-blood clinical samples and external quality controls. The workflows were also compared and we highlighted a significant technician hands-on time reduction (-63%) using the Abbott CMV/EBV maxCycle automated protocol.

Evaluation of the new Abbott Real-Time EBV assay: fully automated quantification of EBV in whole blood by targeting BLLF1

The accurate measurement of the Epstein-Barr virus (EBV) DNA level in the blood is required for managing EBV-associated diseases. A new commercial Abbott Real-Time EBV assay, which targets the BLLF1 gene, was evaluated on 120 clinical whole blood samples and the Qnostics EBV analytical panel. The limit of detection of the assay was 48.9 IU/mL (95% confidence interval, 48.1-49.8 IU/mL). The assay was linear from 2 to 5 log₁₀ IU/mL (R² = 0.997). The within-run coefficients of variation (CVs) ranged from 1.68% to 4.75% and the between-run CVs ranged from 1.73% to 12.83% for samples with high, medium, and low viral loads. EBV DNA loads measured by Abbott EBV assay strongly correlated with the results quantified by another commercial Nanogen EBV Real-Time Alert Q-PCR assay (r = 0.879, P < 0.0001). The fully automated Abbott Real-Time EBV assay targeting BLLF1 reduced both hands-on time and turnaround time and demonstrated a reliable performance for EBV DNA quantification in whole blood.

Plasma Epstein-Barr virus DNA for pediatric Burkitt lymphoma diagnosis, prognosis and response assessment in Malawi

Point-of-care tools are needed in sub-Saharan Africa (SSA) to improve pediatric Burkitt lymphoma (BL) diagnosis and treatment. We evaluated plasma Epstein-Barr virus (pEBV) DNA as a pediatric BL biomarker in Malawi. Prospectively enrolled children with BL were compared to classical Hodgkin lymphoma (cHL) and nonlymphoma diagnoses. Pediatric BL patients received standardized chemotherapy and supportive care. pEBV DNA was measured at baseline, mid-treatment, and treatment completion. Of 121 assessed children, pEBV DNA was detected in 76/88 (86%) with BL, 16/17 (94%) with cHL, and 2/16 (12%) with nonlymphoma, with proportions higher in BL versus nonlymphoma (p < 0.001) and similar in BL versus cHL (p = 0.69). If detected, median pEBV DNA was 6.1 log10 copies/mL for BL, 4.8 log10 copies/mL for cHL, and 3.4 log10 copies/mL for nonlymphoma, with higher levels in BL versus cHL (p = 0.029), and a trend toward higher levels in BL versus nonlymphoma (p = 0.062). pEBV DNA declined during treatment in the cohort overall and increased in several children before clinical relapse. Twelve-month overall survival was 40% in the cohort overall, and for children with baseline pEBV detected, survival was worse if baseline pEBV DNA was ≥6 log10 copies/mL versus <6 log10 copies/mL (p = 0.0002), and also if pEBV DNA was persistently detectable at mid-treatment versus undetectable (p = 0.041). Among children with baseline pEBV DNA detected, viremia was the only significant risk factor for death by 12 months in multivariate analyses (adjusted hazard ratio 1.35 per log10 copies/mL, 95% CI 1.04-1.75, p = 0.023). Quantitative pEBV DNA has potential utility for diagnosis, prognosis, and response assessment for pediatric BL in SSA.