Whole Blood versus Plasma Samples-How Does the Type of Specimen Collected for Testing Affect the Monitoring of Cytomegalovirus Viremia?

Molecular diagnosis of Cytomegalovirus infection: clinical performance of the Aptima transcription-mediated amplification assay toward conventional qPCR chemistry on whole blood samples

Human Cytomegalovirus (HCMV) infection is life-threatening for immunocompromised patients. Quantitative molecular assays on whole blood or plasma are the gold standard for the diagnosis of invasive HCMV infection and for monitoring antiviral treatment in individuals at risk of HCMV disease. For these reasons, an accurate standardization toward the WHO 1st International Standard among different centers and diagnostic kits represents an effort for better clinical management of HCMV-positive patients. Herein, we evaluate, for the first time, the performance of a new transcription-mediated amplification (TMA) assay versus quantitative polymerase chain reaction (qPCR) chemistry, used as a routine method, on whole blood samples. A total of 755 clinical whole blood specimens were collected and tested simultaneously with TMA and qPCR assays. The data showed a qualitative agreement of 99.27% for positive quantified samples and 89.39% for those undetected between the two tested methods. Evaluation of viremia in positive samples highlighted a good correlation between TMA and qPCR chemistries in terms of International Units (ΔLog10 IU/mL: -0.29 ± 0.40). The TMA assay showed a significant correlation with qPCR in patients monitored for up to 3 months, thus allowing an accurate assessment of viremia in transplant patients. Therefore, TMA chemistry showed good agreement with qPCR testing, used as a current diagnostic routine. It also offers important advantages, such as FDA approval on plasma and In Vitro Diagnostic (IVD) on both plasma and whole blood, automated workflow with minimal hands-on time, and random access loading, thus enabling a rapid and reliable diagnostic in HCMV-infected patients.

IMPORTANCE

In this paper, we describe the clinical performance of a novel transcription-mediated amplification (TMA) assay for the detection and quantification of human Cytomegalovirus (HCMV) DNA from whole blood samples. This is a pivotal analysis in immunocompromised patients [transplanted, HIV-positive, and Hematopoietic Stem Cell (HSC) recipients], and molecular tests with high sensitivity and specificity are necessary to evaluate the HCMV viral load in these patients. To our knowledge, this is the first in-depth evaluation of TMA chemistry for HCMV diagnosis on whole blood samples. Moreover, also technical aspects of this assay make it suitable for clinical diagnostics.

Decoding human cytomegalovirus for the development of innovative diagnostics to detect congenital infection

Cytomegalovirus is the most common cause of congenital infectious disease and the leading nongenetic etiology of sensorineural hearing loss. Although most infected neonates are asymptomatic at birth, congenital cytomegalovirus infection is responsible for nearly 400 infant deaths annually in the United States and may lead to significant long-term neurodevelopmental impairments in survivors. The resulting financial and social burdens of congenital cytomegalovirus infection have led many medical centers to initiate targeted testing after birth, with a growing advocacy to advance universal newborn screening. While no cures or vaccines are currently available to eliminate or prevent cytomegalovirus infection, much has been learned over the last five years regarding disease pathophysiology and viral replication cycles that may enable the development of innovative diagnostics and therapeutics. This Review will detail our current understanding of congenital cytomegalovirus infection, while focusing our discussion on routine and emerging diagnostics for viral detection, quantification, and long-term prognostication. IMPACT: This review highlights our current understanding of the fetal transmission of human cytomegalovirus. It details clinical signs and physical findings of congenital cytomegalovirus infection. This submission discusses currently available cytomegalovirus diagnostics and introduces emerging platforms that promise improved sensitivity, specificity, limit of detection, viral quantification, detection of genomic antiviral resistance, and infection staging (primary, latency, reactivation, reinfection).

Antiviral Approach to Cytomegalovirus Infection: An Overview of Conventional and Novel Strategies

Human cytomegalovirus (HCMV) is a herpesvirus capable of establishing a lifelong persistence in the host through a chronic state of infection and remains an essential global concern due to its distinct life cycle, mutations, and latency. It represents a life-threatening pathogen for immunocompromised patients, such as solid organ transplanted patients, HIV-positive individuals, and hematopoietic stem cell recipients. Multiple antiviral approaches are currently available and administered in order to prevent or manage viral infections in the early stages. However, limitations due to side effects and the onset of antidrug resistance are a hurdle to their efficacy, especially for long-term therapies. Novel antiviral molecules, together with innovative approaches (e.g., genetic editing and RNA interference) are currently in study, with promising results performed in vitro and in vivo. Since HCMV is a virus able to establish latent infection, with a consequential risk of reactivation, infection management could benefit from preventive treatment for critical patients, such as immunocompromised individuals and seronegative pregnant women. This review will provide an overview of conventional antiviral clinical approaches and their mechanisms of action. Additionally, an overview of proposed and developing new molecules is provided, including nucleic-acid-based therapies and immune-mediated approaches.

Diagnostic Value of Whole-Blood and Plasma Samples in Epstein-Barr Virus Infections

Epstein-Barr virus (EBV) is an oncogenic virus classified by the World Health Organization as a class 1 carcinogen. Post-transplant lymphoproliferative disorders are believed to be strongly related to an EBV infection. Monitoring of EBV DNAemia is recommended to assess the risk of reactivation of latent infection and to assess the effectiveness of therapy. Currently, various types of clinical specimens are used for this purpose. The aim of the study was to assess a reliable method of EBV viral load investigation depending on the clinical material used: whole blood or plasma samples. We found that of 134 EBV-DNA-positive whole-blood samples derived from 51 patients (mostly hemato-oncology or post-transplantation), only 43 (32.1%) were plasma-positive. Of these, 37 (86.0%) had lower plasma DNAemia compared to the corresponding whole-blood samples. We conclude that whole-blood samples have a higher sensitivity than plasma samples in EBV DNA detection. The clinical utility of the tests is unclear, but our results suggest that either whole blood or plasma should be used consistently for EBV viral load monitoring.