Differences in Duration and Degree of Cytomegalovirus DNAemia Observed With Two Standardized Quantitative Nucleic Acid Tests and Implications for Clinical Care

A practical guide to real-world implementation of pre-emptive therapy for Cytomegalovirus disease prevention in high-risk seronegative liver transplant recipients with seropositive donors

The Comparison of Antiviral Preventative Strategies In Liver Transplant (CAPSIL) study showed pre-emptive therapy (PET) to be superior to antiviral prophylaxis for Cytomegalovirus (CMV) disease prevention in high-risk CMV seronegative liver transplant recipients (LTRs) with seropositive donors (D+R-). Despite the statistical superiority of PET over prophylaxis in research settings, PET is perceived as a logistically more complex strategy that requires careful coordination of weekly CMV PCR testing, prompt initiation of CMV antivirals upon viremia detection, and timely cessation of antivirals following viremia resolution. Transplant centers may be hesitant to use PET for CMV disease prevention in D+R- LTRs out of concern that PET coordination is not feasible in clinical practice. We recently described our experience using PET in CMV D+R- LTRs in a real-world setting, and found it to be as effective for CMV disease prevention as PET performed as part of a clinical trial. Here, we describe a systematic approach for PET implementation in real-world settings and provide practical tools to address anticipated challenges. This framework can support transplant programs in overcoming logistical barriers to PET and incorporating an evidence-based and cost-effective CMV prevention strategy into routine care for high-risk CMV D+R- LTRs.

Performance evaluation of fully automated cobas® 6800 CMV PCR for the detection and quantification of cytomegalovirus DNA in neonatal urine and saliva, and adult urine, saliva, and vaginal secretion

Laboratory testing for cytomegalovirus (CMV) in bodily fluids is essential to manage congenital and prenatal CMV infection. The rapid and fully automated cobas® CMV PCR is approved only for the testing of plasma in transplant patients. To evaluate the performance of the cobas® CMV to detect and quantify CMV DNA in neonatal and adult female urine, saliva, and vaginal secretion, the limit of detection (LoD), limit of quantification (LoQ), imprecision, linearity, PCR efficiency, bias, analytical specificity, cross-reactivity, and cross-contamination of the cobas® CMV for urine, saliva, and vaginal secretion was determined. The performance of the assay was evaluated prospectively with two laboratory-developed PCR assays using neonatal and adult urine, saliva swabs, and vaginal swabs. The LoD and LoQ were 31 and 100 IU/mL, respectively, for urine, and 81 and 100 IU/mL, respectively, for vaginal secretion. The LoD and LoQ for saliva were the same (200 IU/mL). The cobas® CMV was precise (coefficient of variation ≤10%), linear (R2  ≥ 0.995), and efficient (1.07 and 1.09) between 100 and 250,000 IU/mL for the sample types. The bias and analytical specificity was <±0.30 log10 IU/mL and 100%, respectively. Cross-reactivity with non-CMV pathogens was not detected. Cross-contamination rate was 0.28%. The diagnostic accuracy, sensitivity, and specificity of the cobas® CMV for neonatal urine and saliva were ≥95.0%, ≥93.3%, and ≥90.4%, respectively. The overall percent agreement for adult urine, saliva, and vaginal secretion was 86.6%, 94.5%, and 89.4%, respectively. Taken together, the cobas® CMV demonstrated acceptable analytical and diagnostic performance, and is suitable for routine diagnostic laboratory investigation of CMV infection in neonates and adults.

Advances and Challenges in Cytomegalovirus Detection Methods for Liver Transplant Donors

Cytomegalovirus (CMV) infection is a highly prevalent opportunistic infection among liver transplant recipients. When the liver donor is infected with CMV, there is a risk of transmission to the recipient, leading to CMV infection. To improve the postoperative outcome of liver transplantation, it is crucial to shift the focus of CMV detection to the donor and achieve early diagnosis, as well as implement effective preventative and therapeutic measures. However, the commonly used CMV detection methods in the past had limitations that prevented their early and accurate diagnosis in liver transplant donors. This review focuses on the latest advancements in CMV detection methods that can potentially be applied to liver transplant donors. The objective is to compare and evaluate their clinical utility, thereby providing guidance and support for rapid and accurate diagnosis of CMV infection in the clinic. The clustered regularly interspaced short palindromic repeats-associated proteins (CRISPR-Cas) system-based assay emerges as a promising method for detecting the virus, offering great prospects for early and expedient CMV infection diagnosis in clinical settings.

Amplicon size and non-encapsidated DNA fragments define plasma cytomegalovirus DNA loads by automated nucleic acid testing platforms: A marker of viral cytopathology?

Management of cytomegalovirus (CMV) in transplant patients relies on measuring plasma CMV-loads using quantitative nucleic acid testing (QNAT). We prospectively compared the automated Roche-cobas®6800-CMV and Roche-CAP/CTM-CMV with laboratory-developed Basel-CMV-UL54-95bp, and Basel-CMV-UL111a-77bp. Roche-cobas®6800-CMV and Roche-CAP/CTM-CMV were qualitatively concordant in 142/150 cases (95%). In-depth comparison revealed higher CMV-loads of the laboratory-developed assay and correlated with smaller amplicon size. After calibration to the 1.WHO-approved CMV international standard, differences were reduced but remained significant. DNase-I pretreatment significantly reduced CMV-loads for both automated Roche-CAP/CTM-CMV and Roche-cobas®6800-CMV assays, whereby 90% and 95% of samples became undetectable. DNase-I pretreatment also reduced CMV-loads quantified by Basel-CMV-UL54-95bp and Basel-CMV-UL111a-77bp, but remaining detectable in 20% and 35%, respectively. Differences were largest for 110 samples with low-level CMV-DNAemia being detectable but not-quantifiable by Roche-cobas®6800-CMV, whereby the smaller amplicon sizes yielded higher viral loads for concordant positives. We conclude that non-encapsidated fragmented CMV-DNA is the major form of plasma CMV-loads also measured by fully-automated platforms. Amplicons of <150 bp and calibrators are needed for reliable and commutable QNAT-results. We hypothesize that non-encapsidated fragmented CMV-DNA results from lysis of CMV-replicating cells and represent a direct marker of viral cell damage, which contribute to delayed viral load responses despite effective antivirals.

The burden of cytomegalovirus infection remains high in high-risk kidney transplant recipients despite six-month valganciclovir prophylaxis

Cytomegalovirus continues to be a concern after transplantation despite prophylaxis regimens. Our aim was to analyse post-prophylaxis primary cytomegalovirus infections among kidney transplant recipients after 6-month valganciclovir prophylaxis and to determine the usefulness of surveillance after prophylaxis. Data from all cytomegalovirus D+/R- kidney transplant recipients from January 2004 to October 2018 at our center who received 6-month prophylaxis with valganciclovir were retrospectively analysed (N = 481). Detailed analyses were performed for 136 patients who were monitored every 2-4 weeks for DNAemia after the discontinuation of prophylaxis. Post-prophylaxis primary cytomegalovirus infection occurred in 182/481 (38%) patients median 264 days after transplantation (IQR: 226-367) and median 84 days after the end of prophylaxis (IQR: 46-187). In 49% patients, cytomegalovirus infection occurred over 3 months after the end of prophylaxis. Cytomegalovirus infection was not associated with lower patient or graft survival and no independent risk factors for infection were found. From patients monitored closely, 71/136 (52%) patients developed post-prophylaxis primary cytomegalovirus infection. Altogether, 52/136 (38%) patients were diagnosed with probable post-prophylaxis cytomegalovirus disease and 19/136 (14%) patients had asymptomatic CMV infection. Recurrent infection occurred in 38/71 (39%) patients. The incidence of post-prophylaxis primary cytomegalovirus infection among D+/R- kidney transplant recipients remains high despite 6-month prophylaxis. Surveillance after prophylaxis was challenging as a considerable portion of the infections occurred late and already symptomatic.

Progress and Challenges in the Prevention, Diagnosis, and Management of Cytomegalovirus Infection in Transplantation

Hosts with compromised or naive immune systems, such as individuals living with HIV/AIDS, transplant recipients, and fetuses, are at the highest risk for complications from cytomegalovirus (CMV) infection. Despite substantial progress in prevention, diagnostics, and treatment, CMV continues to negatively impact both solid-organ transplant (SOT) and hematologic cell transplant (HCT) recipients. In this article, we summarize important developments in the field over the past 10 years and highlight new approaches and remaining challenges to the optimal control of CMV infection and disease in transplant settings.

Features of Cytomegalovirus DNAemia Blips in Allogeneic Hematopoietic Stem Cell Transplant Recipients: Implications for Optimization of Preemptive Antiviral Therapy Strategies

Cytomegalovirus (CMV) DNAemia occurs frequently in allogeneic hematopoietic stem cell transplant recipients (allo-HSCT). There is limited information about the incidence, features, and clinical impact of CMV DNAemia blips (episodes defined by an isolated positive PCR result) in this setting. In this retrospective study, 225 consecutive adult patients undergoing any modality of allo-HSCT at our center between May 2012 and July 2019 were included. Plasma CMV DNA load was monitored using a highly sensitive real-time PCR assay. In all, 187 of 225 patients had CMV DNAemia through day 365 after allo-HSCT (total number of episodes, n = 379). Eighty-three of the 187 patients had 1 or more blips (n = 104). Blips occurred as a first episode of CMV DNAemia as opposed to prolonged CMV DNAemia (≥2 consecutive positive PCR results) in 47 patients; in 20 of these patients, blips represented the only documented episode throughout the study period, and in 27 patients, blips preceded a prolonged CMV DNAemia episode. In the remaining 36 patients, blips developed as recurrences. Blips presenting as initial episodes occurred more frequently (P < .001) in patients receiving an allograft from a CMV-seropositive donor. The cumulative incidence of recurrent CMV DNAemia following initial blips, self-resolving prolonged CMV DNAemia episodes, or CMV DNAemia episodes treated preemptively with antivirals was not significantly different (P = .34). Receiver operating characteristic curve analysis indicated that a CMV DNA load cutoff of 48 IU/mL yielded the highest combined sensitivity (66%) and specificity (70.2%) for predicting a prolonged CMV DNAemia episode. The practical implications of our data in the optimization of preemptive antiviral therapy strategies are discussed.