Clinical Diagnostic Testing for Human Cytomegalovirus Infections

Designing a novel multi-epitope antigen for diagnosing human cytomegalovirus infection: An immunoinformatics approach

Human cytomegalovirus (HCMV) infection can lead to congenital infections and severe complications, particularly in immunocompromised individuals. Current serological tests for diagnosing HCMV infection often face limitations in sensitivity and specificity. Developing multi-epitope antigens for serological assays offers the potential for enhancing diagnostic accuracy. This study aimed to design a novel multi-epitope antigen for HCMV infection diagnosis using immunoinformatic approaches. Five tegument proteins (universal protein resource [UniProt] ID: Po8318, Po6725, F5HC97, Q6RX10, and F5HC05) were selected based on their antigenic properties and literature review. Six linear B-cell epitopes were predicted within conserved regions of each antigen sequence and linked with appropriate linkers. The designed multi-epitope antigen underwent thorough evaluation for physicochemical properties, solubility, antigenicity, and cross-reactivity. Additionally, the three-dimensional structure of the antigen was predicted, refined, and validated. The nucleotide sequence of the designed antigen was optimized for successful expression in Escherichia coli and inserted into a pET23a (+) vector. Immunoinformatic analysis revealed that the multi-epitope antigen exhibits stability, antigenicity, and lacks cross-reactivity. Our findings suggest that this multi-epitope antigen is a promising candidate for diagnosing HCMV infection. However, further validation through laboratory testing is required to confirm its diagnostic efficacy.

Discrimination of primary and chronic cytomegalovirus infection based on humoral immune profiles in pregnancy

BACKGROUNDMost humans have been infected with cytomegalovirus (CMV) by midlife without clinical signs of disease. However, in settings in which the immune system is undeveloped or compromised, the virus is not adequately controlled and consequently presents a major infectious cause of both congenital disease during pregnancy as well as opportunistic infection in children and adults. With clear evidence that risk to the fetus varies with gestational age at the time of primary maternal infection, further research on humoral responses to primary CMV infection during pregnancy is needed.METHODSHere, systems serology tools were applied to characterize antibody responses to CMV infection in pregnant and nonpregnant women experiencing either primary or chronic infection.RESULTSWhereas strikingly different antibody profiles were observed depending on infection status, limited differences were associated with pregnancy status. Beyond known differences in IgM responses used clinically for identification of primary infection, distinctions observed in IgA and FcγR-binding antibodies and among antigen specificities accurately predicted infection status. Machine learning was used to define the transition from primary to chronic states and predict time since infection with high accuracy. Humoral responses diverged over time in an antigen-specific manner, with IgG3 responses toward tegument decreasing over time as typical of viral infections, while those directed to pentamer and glycoprotein B were lower during acute and greatest during chronic infection.CONCLUSIONIn sum, this work provides insights into the antibody response associated with CMV infection status in the context of pregnancy, revealing aspects of humoral immunity that have the potential to improve CMV diagnostics.FUNDINGCYMAF consortium and NIH NIAID.

Prognostic significance of plasma cytomegalovirus (CMV) DNA load in immunocompetent patients with CMV pneumonia: A retrospective cohort study

Cytomegalovirus (CMV) pneumonia, often presented as pneumonitis, is characterized by respiratory failure and large interstitial infiltrates visible on chest radiographs. This retrospective cohort study investigates the predictive significance of plasma CMV DNA load on the short- and long-term mortality among immunocompetent patients diagnosed with CMV pneumonia. The study included 61 immunocompetent patients suspected of having CMV pneumonia, treated with intravenous ganciclovir after positive CMV DNA results from bronchoalveolar lavage or plasma. Our multivariate Cox regression analysis identified several independent predictors of mortality. Having idiopathic pulmonary fibrosis (IPF) significantly increased the risk of in-hospital mortality (HR: 7.27, 95% CI: 1.62-32.52, p = 0.009), as did shorter durations of antiviral therapy (HR: 0.90, 95% CI: 0.84-0.97, p = 0.005) and higher CMV DNA levels (>3870 IU/mL; HR: 9.63, 95% CI: 2.32-39.98, p = 0.002). High CMV DNA levels (>5154 IU/mL) were also predictors of 30-day mortality (HR: 9.39, 95% CI: 2.20-40.01, p = 0.002). For 1-year mortality, the presence of IPF (HR: 2.96, 95% CI: 1.08-8.06, p = 0.034), hypersensitivity pneumonia (HP) (HR: 4.30, 95% CI: 1.57-11.78, p = 0.005), shorter duration of total antiviral therapy (HR: 0.95, 95% CI: 0.93-0.99, p = 0.010), and higher CMV DNA levels (>327 IU/mL) (HR: 3.36, 95% CI: 1.33-8.47, p = 0.010) were identified as independent determinants. The study reveals that IPF increases short and long-term mortality risks, while HP increases long-term mortality. Extended antiviral treatment duration results in a 10% reduction in in-hospital mortality for each additional day of treatment. Furthermore, elevated viral loads are associated with higher mortality rates, highlighting the necessity for careful monitoring.

Evaluating metagenomics and targeted approaches for diagnosis and surveillance of viruses

BACKGROUND

Metagenomics is a powerful approach for the detection of unknown and novel pathogens. Workflows based on Illumina short-read sequencing are becoming established in diagnostic laboratories. However, high sequencing depth requirements, long turnaround times, and limited sensitivity hinder broader adoption. We investigated whether we could overcome these limitations using protocols based on untargeted sequencing with Oxford Nanopore Technologies (ONT), which offers real-time data acquisition and analysis, or a targeted panel approach, which allows the selective sequencing of known pathogens and could improve sensitivity.

METHODS

We evaluated detection of viruses with readily available untargeted metagenomic workflows using Illumina and ONT, and an Illumina-based enrichment approach using the Twist Bioscience Comprehensive Viral Research Panel (CVRP), which targets 3153 viruses. We tested samples consisting of a dilution series of a six-virus mock community in a human DNA/RNA background, designed to resemble clinical specimens with low microbial abundance and high host content. Protocols were designed to retain the host transcriptome, since this could help confirm the absence of infectious agents. We further compared the performance of commonly used taxonomic classifiers.

RESULTS

Capture with the Twist CVRP increased sensitivity by at least 10-100-fold over untargeted sequencing, making it suitable for the detection of low viral loads (60 genome copies per ml (gc/ml)), but additional methods may be needed in a diagnostic setting to detect untargeted organisms. While untargeted ONT had good sensitivity at high viral loads (60,000 gc/ml), at lower viral loads (600-6000 gc/ml), longer and more costly sequencing runs would be required to achieve sensitivities comparable to the untargeted Illumina protocol. Untargeted ONT provided better specificity than untargeted Illumina sequencing. However, the application of robust thresholds standardized results between taxonomic classifiers. Host gene expression analysis is optimal with untargeted Illumina sequencing but possible with both the CVRP and ONT.

CONCLUSIONS

Metagenomics has the potential to become standard-of-care in diagnostics and is a powerful tool for the discovery of emerging pathogens. Untargeted Illumina and ONT metagenomics and capture with the Twist CVRP have different advantages with respect to sensitivity, specificity, turnaround time and cost, and the optimal method will depend on the clinical context.

HerpesDRG: a comprehensive resource for human herpesvirus antiviral drug resistance genotyping

The prevention and treatment of many herpesvirus associated diseases is based on the utilization of antiviral therapies, however therapeutic success is limited by the development of drug resistance. Currently no single database cataloguing resistance mutations exists, which hampers the use of sequence data for patient management. We therefore developed HerpesDRG, a drug resistance mutation database that incorporates all the known resistance genes and current treatment options, built from a systematic review of available genotype to phenotype literature. The database is released along with an R package that provides a simple approach to resistance variant annotation and clinical implication analysis from common sanger and next generation sequencing data. This represents the first openly available and community maintainable database of drug resistance mutations for the human herpesviruses (HHV), developed for the community of researchers and clinicians tackling HHV drug resistance.

Antiviral Agents for Preventing Cytomegalovirus Disease in Recipients of Hematopoietic Cell Transplantation

This systematic review discusses the use of prophylaxis to prevent cytomegalovirus (CMV) infection in recipients who have undergone hematopoietic cell transplantation. It highlights the need for new approaches to control and prevent CMV infection. The approval of the anti-CMV drug letermovir has made antiviral prophylaxis more popular. CMV-specific T cell-mediated immunity tests are effective in identifying patients who have undergone immune reconstitution and predicting disease progression. Maribavir (MBV) has been approved for the treatment of post-transplant CMV infection/disease in adolescents. Adoptive T-cell therapy and the PepVax CMV vaccine show promise in tackling refractory and resistant CMV. However, the effectiveness of PepVax in reducing CMV viremia/disease was not demonstrated in a phase II trial. Cell-mediated immunity assays are valuable for personalized management plans, but more interventional studies are needed. MBV and adoptive T-cell therapy are promising treatments, and trials for CMV vaccines are ongoing.

Evaluation of Alinity m CMV assay performance for detecting CMV in plasma, cerebrospinal fluid, and bronchoalveolar lavage specimens

Accurate detection and quantification of cytomegalovirus (CMV) is crucial to preventing adverse outcomes in immunocompromised individuals. Current assays were developed for use with plasma specimens, but CMV may be present in bronchoalveolar lavage (BAL) fluid and cerebrospinal fluid (CSF). We evaluated the performance of the Abbott Alinity m CMV assay compared to the Abbott RealTime CMV assay for quantification of CMV in plasma, BAL, and CSF specimens. To evaluate clinical performance, 190 plasma, 78 BAL, and 20 CSF specimens were tested with the Alinity m assay and compared to the RealTime assay. The Alinity m CMV assay showed high precision (SD <0.01 to 0.13) for all 3 specimen types. Clincal plasma and BAL specimens with quantifiable CMV DNA demonstrated strong correlation to RealTime CMV assay results (r2 = 0.9779 for plasma, r2 = 0.9373 for BAL). The Alinity m CMV assay may be useful for quantification of CMV in plasma, BAL, and CSF specimens.

Comprehensive bioinformatics analysis of human cytomegalovirus pathway genes in pan-cancer

BACKGROUND

Human cytomegalovirus (HCMV) is a herpesvirus that can infect various cell types and modulate host gene expression and immune response. It has been associated with the pathogenesis of various cancers, but its molecular mechanisms remain elusive.

METHODS

We comprehensively analyzed the expression of HCMV pathway genes across 26 cancer types using the Cancer Genome Atlas (TCGA) and The Genotype-Tissue Expression (GTEx) databases. We also used bioinformatics tools to study immune invasion and tumor microenvironment in pan-cancer. Cox regression and machine learning were used to analyze prognostic genes and their relationship with drug sensitivity.

RESULTS

We found that HCMV pathway genes are widely expressed in various cancers. Immune infiltration and the tumor microenvironment revealed that HCMV is involved in complex immune processes. We obtained prognostic genes for 25 cancers and significantly found 23 key genes in the HCMV pathway, which are significantly enriched in cellular chemotaxis and synaptic function and may be involved in disease progression. Notably, CaM family genes were up-regulated and AC family genes were down-regulated in most tumors. These hub genes correlate with sensitivity or resistance to various drugs, suggesting their potential as therapeutic targets.

CONCLUSIONS

Our study has revealed the role of the HCMV pathway in various cancers and provided insights into its molecular mechanism and therapeutic significance. It is worth noting that the key genes of the HCMV pathway may open up new doors for cancer prevention and treatment.

Metagenomic Next-Generation Sequencing Contributes to the Early Diagnosis of Mixed Infections in Central Nervous System

Central nervous system (CNS) infections represent a challenge due to the complexities associated with their diagnosis and treatment, resulting in a high incidence rate and mortality. Here, we presented a case of CNS mixed infection involving Candida and human cytomegalovirus (HCMV), successfully diagnosed through macrogenomic next-generation sequencing (mNGS) in China. A comprehensive review and discussion of previously reported cases were also provided. Our study emphasizes the critical role of early pathogen identification facilitated by mNGS, underscoring its significance. Notably, the integration of mNGS with traditional methods significantly enhances the diagnostic accuracy of CNS infections. This integrated approach has the potential to provide valuable insights for clinical practice, facilitating early diagnosis, allowing for treatment adjustments, and ultimately, improving the prognosis for patients with CNS infections.

Rapid and sensitive point-of-care diagnosis of human cytomegalovirus infection using RPA-CRISPR technology

Background

Human cytomegalovirus (HCMV) is a common herpesvirus that can cause a range of symptoms, from mild conditions such as fevers to severe illnesses like pneumonia. Early and accurate diagnosis of HCMV infection is crucial, particularly for vulnerable populations with limited medical care. However, current diagnostic methods are often expensive, time-consuming, and require skilled technicians.

Materials and methods

We developed an HCMV-RPA-CRISPR diagnosis platform for the rapid and cost-effective detection of HCMV infection. This method utilizes recombinase polymerase amplification (RPA) to amplify the HCMV target gene isothermally without the need for thermal cycling equipment. The platform integrates the CRISPR/Cas12a system, significantly enhancing specificity and sensitivity. A total of 13 clinical blood samples were tested to evaluate the platform's effectiveness and accuracy. Additionally, a lateral flow assay (LFA) and fluorescence detection were incorporated for straightforward and rapid visual interpretation of the results.

Results

The assay effectively detected concentrations as low as a single copy of the positive control plasmid per microliter in under 1 h, without requiring specialized equipment or training. In clinical sample evaluations, both the fluorescence readout and LFA exhibited 100% sensitivity and specificity, identifying four HCMV-positive and nine HCMV-negative samples.

Conclusion

The HCMV-RPA-CRISPR diagnosis platform is comparably effective to qPCR for HCMV diagnosis. Its applicability in common clinical laboratories, clinics, and point-of-care settings, particularly in resource-limited environments, makes it a valuable tool for widespread HCMV screening and diagnosis.

Maternal and congenital human cytomegalovirus infection: laboratory testing for detection and diagnosis

Human cytomegalovirus (CMV) is the leading cause of congenital infection worldwide and the most common cause of non-genetic sensorineural hearing loss. As there is no vaccine or other specific intervention to prevent congenital CMV infection, there is a need to identify maternal and congenital infections with sensitive and specific testing as early as possible. There is no widely accepted practice for screening during pregnancy or in all newborns for identification of possible cases of congenital CMV. Currently, screening during pregnancy is limited to those identified as at risk followed by fetal and/or neonatal testing when congenital infection is suspected. This review focuses primarily on the current status of laboratory testing for diagnosis of maternal and congenital CMV infections. Primary maternal infection is best diagnosed using serologic testing, including CMV IgM, IgG, and avidity testing, while fetal infection should be assessed by nucleic acid amplification testing (NAAT) of amniotic fluid. Urine and saliva NAATs are the mainstay for diagnosis of congenital CMV in the first 3 weeks of life. Testing of dried blood spots can be useful for diagnosis of congenital CMV outside of the newborn period. The gaps in knowledge such as the prognostic value of viral loads in various sample types are addressed.

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.

Susceptibility of solid organ transplant recipients to viral pathogens with zoonotic potential: A mini-review

A substantial number of zoonotic diseases are caused by viral pathogens, representing a significant menace to public health, particularly to susceptible populations, such as pregnant women, the elderly, and immunocompromised individuals. Individuals who have undergone solid organ transplantation frequently experience immunosuppression, to prevent organ rejection, and, thus are more prone to opportunistic infections. Furthermore, the reactivation of dormant viruses can threaten transplant recipients and organ viability. This mini-review examines the up-to-date literature covering potential zoonotic and organ rejection-relevant viruses in solid organ transplant recipients. A comprehensive list of viruses with zoonotic potential is highlighted and the most important clinical outcomes in patients undergoing transplantation are described. Moreover, this mini-review calls attention to complex multifactorial events predisposing viral coinfections and the need for continuous health surveillance and research to understand better viral pathogens' transmission and pathophysiology dynamics in transplanted individuals.

Challenges in Diagnosing Post-Splenectomy Cytomegalovirus Mononucleosis

Cytomegalovirus (CMV) infection is often asymptomatic. However, in certain individuals, it can cause non-specific signs and symptoms that maybe hard to recognise. The condition may therefore be overlooked or misdiagnosed, leading to prolonged illness and serious sequelae. In this case report, we present a rare instance of CMV infection in an HIV-negative patient who had a remote history of splenectomy and was experiencing prolonged fever and markedly elevated white blood cell (WBC) count.

LEARNING POINTS

The clinical presentation of CMV infection in a post-splenectomy patient can be intricate and deceptive, involving non-specific symptoms such as prolonged fever and a markedly elevated WBC count.The decision on treatment among individuals without apparent risk factors (such as AIDS, transplant, or cancers) led to in-depth deliberations and discussion.Post-splenectomy patients with CMV infection may exhibit prolonged illness, potentially leading to severe consequences if left untreated.

Early detection, reactivation of cytomegalovirus DNA & immediate early (IE)-mRNA expression in hematopoietic stem cell-transplant patients

BACKGROUND

Human cytomegalovirus (HCMV) reactivation is a major cause of morbidity and mortality among stem cell transplant recipients post-transplantation.

AIM

HCMV immediate-early messenger RNA (IE-mRNA) was evaluated as marker of post-transplant HCMV reactivation in bone marrow transplant recipients.

METHOD

ology: An in-house real-time reverse transcriptase PCR targeting IE-mRNA was developed to estimate HCMV mRNA levels post-transplantation. Blood samples collected in K2-EDTA tubes from patients (n = 162) admitted with Department of Clinical Hematology were transported in cold condition for routine HCMV DNA screening. For HCMV IE-mRNA quantification, peripheral blood mononuclear cells (PBMCs) were separated from whole blood and stored in RNA later at -70 °C until testing. Samples were collected weekly once for first 3 weeks post-transplantation and thereafter from week 4-12, samples were collected twice weekly. A total of 2467 samples were collected from 162 study participants.

RESULTS

Thirty five patients (21.6 %) had post-transplant HCMV reactivation. Twenty five patients with complete follow-up were selected for monitoring HCMV DNA. HCMV IE-mRNA PCR was performed for 15 patients and 7(46.6 %) patients had detectable mRNA levels. HCMV IE-mRNA was detected in all patients with increasing HCMV DNA levels except for one patient in whom IE-mRNA appeared 3 days before HCMV DNA was detected. One patient had detectable HCMV IE-mRNA during declining HCMV DNA level. However the patient showed an increased HCMV DNA one week later, indicating the importance of HCMV mRNA in predicting HCMV replication.

CONCLUSION

Quantification of HCMV IE-mRNA may be a valuable tool to predict progression of HCMV infection post-transplantation, with further prospective studies needed for validation.

Fetal brain imaging provides valuable information in cCMV infected infants

BACKGROUND

Congenital CMV infection (cCMV) is the most common congenital infection with 10-15% of cases developing symptomatic disease. Early antiviral treatment is of essence when symptomatic disease is suspected. Recently, the use of neonatal imaging has been implicated as a prognostic tool for long term sequalae among asymptomatic newborns at high risk. Even though neonatal MRI is commonly used in neonatal symptomatic cCMV disease, it is less often used in asymptomatic newborns, mainly due to cost, access and difficulty to perform. We have therefore developed an interest in assessing the use of fetal imaging as an alternative. Our primary aim was to compare the fetal and neonatal MRIs in a small cohort 10 asymptomatic neonates with congenital CMV infection.

METHODS

We performed a single-center retrospective cohort study (case-series) on a convenience sample of children born from January 2014 to March 2021 with confirmed congenital CMV infection who had undergone both fetal and neonatal MRIs. We created a checklist of relevant cerebral abnormalities and asked 4 blinded radiologists to assess the MRIs (2 for each, namely fetal and neonatal) and then compared the findings between the fetal and neonatal imaging as well as the concordance in reporting of abnormalities within each category.

FINDINGS

Overall concordance between prenatal and postnatal scans was high (70%). When comparing the two blinded reports for each MRI, we found high levels of concordance: 90% concordance for fetal MRIs and 100% for neonatal MRIs. The most common abnormalities identified in both fetal and neonatal scans were "abnormal white matter hyperintensity" and "subependymal cysts."

INTERPRETATION

Even though this is a small descriptive study, it indicates that fetal MRI could potentially provide us with similar information as neonatal imaging. This study could form the basis for subsequent larger future studies.

A broad-based probe-free qPCR assay for detection and discrimination of three human herpes viruses

Primary infection or reactivation of latent human cytomegalovirus (HCMV) or herpes simplex viruses (HSV) 1 or 2 during pregnancy can transmit the virus in utero or during natural childbirth to the fetus. The majority of these infections are asymptomatic at birth but may present later with potentially lethal disseminated infection or meningitis (HSV), or long-term neurodevelopmental sequelae including sensorineural hearing loss or neurodevelopmental impairments (HCMV). Unfortunately, early signs and symptoms of disseminated viral infections may be misdiagnosed as bacterial sepsis. Therefore, immediate testing for viral etiologies may not be ordered or even considered by skilled clinicians. In asymptomatic HCMV infections, early detection is necessary to monitor for and treat future neurologic sequelae. In acutely ill-appearing infants, specific detection of viruses against other disease-causing agents is vital to inform correct patient management, including early administration of the correct antimicrobial(s). An ideal test should be rapid, inexpensive, require low sample volumes, and demonstrate efficacy in multiple tissue matrices to aid in timely clinical decision-making for neonatal infections. This work discusses the development of a rapid probe-free qPCR assay for HSV and HCMV that enables early and specific detection of these viruses in neonates. The assay's probe free chemistry would allow easier extension to a broad-based multiplexed pathogenic panel as compared to assays utilizing sequence-specific probes or nested PCR.

Assessment of an automated Cytomegalovirus nucleic acid amplification test using clinical plasma, bronchoalveolar lavage, and tissue specimens

BACKGROUND

Cytomegalovirus (CMV) causes significant morbidity and mortality in immunocompromised patients, particularly transplant recipients. Quantitation of CMV DNA in peripheral blood is used to monitor prophylactic and pre-emptive approaches to prevent CMV disease, whereas CMV DNA testing of non-plasma specimens may aid in the diagnosis of end-organ disease.

METHODS

The analytical performance of the FDA-approved Aptima CMV Quant Assay was evaluated using reference CMV (SeraCare) diluted in defibrinated human plasma, as well as negative bronchoalveolar lavage fluid and tissue. Agreement was determined using 100 clinical acid-citrate-dextrose (ACD) plasma specimens, 77 bronchoalveolar lavage (BAL) fluids, and 101 tissues previously tested using artus CMV qPCR.

RESULTS

Aptima CMV lower limit of detection (LLOD) was 169 IU/mL for ACD plasma, 100 IU/mL for BAL, and 50 IU/mL for tissue. Positive percent agreement (PPA) was 100.0% (50/50; 95% CI: 92.9% - 100.0%) and negative percent agreement (NPA) was 94.0% (47/50; 95% CI: 83.5% - 98.8%) for ACD plasma. Bland-Altman analysis revealed a bias of 0.20 log10 IU/mL (Aptima - artus) with 95% limits of agreement of -0.53 to 0.93. For BAL fluids, PPA was 70.0% (14/20; 95% CI: 45.7% - 88.1%) and NPA was 82.4% (43/51; 95% CI: 69.1% - 91.6%). For tissues, PPA was 90.0% (45/50; 95% CI: 78.2% - 96.7%) and NPA was 94.0% (47/50; 95% CI: 83.5% - 98.8%).

CONCLUSIONS

The Aptima CMV Quant Assay demonstrates high analytical sensitivity and good overall agreement using clinical plasma and tissue specimens.

Comparable cytokine release ex-vivo by whole blood from COVID-19 patients with and without non-invasive ventilation

T cells are key players in the resolution of the infection by SARS-CoV-2. A delay in their activation can lead to severe COVID-19. The present work aimed to identify differences in cytokine release by T cells ex-vivo between COVID-19 patients in the acute phase, showing diverse disease severity. Concentrations of IFNγ, Granzyme B, IL-6, IL-10, IL-17A, IL-18, IP-10, MCP-1, and TNFα were evaluated after stimulation ex-vivo of whole blood samples with peptides from SARS-CoV-2 spike protein and a mitogen as well as without stimulation. Samples derived from hospitalized COVID-19 patients and SARS-CoV-2 vaccinated controls (CTR). Patients were classified on disease severity considering the necessity of non-invasive ventilation (NIV). Samples from patients requiring NIV revealed a similar release of cytokines compared with patients without NIV. COVID-19 patients showed higher spontaneous production of IFNγ and IP-10, lower production of MCP-1 after SARS-CoV-2 peptide stimulation and lower production of IFNγ, IL-10, IL-17A, Granzyme B, IP-10 after mitogenic stimulus compared with CTR. In conclusion, differences in T cell responses evaluated ex-vivo by a whole blood-based cytokine release assay do not appear to explain the need for non-invasive ventilation in COVID-19 patients.

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.

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.

Antiviral Treatment of Maternal and Congenital Cytomegalovirus (CMV) Infections

Human Cytomegalovirus (HCMV) is a ubiquitous member of the Herpesviridae family, responsible for the most common congenital viral infection-congenital Cytomegalovirus (cCMV) infection. While a majority of HCMV infections in children and adults are asymptomatic, HCMV is well known to cause severe infections in the immunocompromised individual and maternal infections with variable long-term sequelae after maternal-fetal transmission with primary or nonprimary infections. HCMV seroprevalence and cCMV incidence vary by geographic area and demographic characteristics like race and socioeconomic status. While cCMV birth prevalence ranges from 0.2% to 6% in different parts of the world, it is influenced by regional HCMV seroprevalence rates. HCMV screening during pregnancy is not routinely offered due to lack of awareness, hurdles to accurate diagnosis, and lack of well-established effective treatment options during pregnancy. This review will focus on antiviral treatment options currently available for use during pregnancy and in the newborn period for the treatment of maternal and congenital HCMV infections.

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.

Integrated immune monitoring of HCMV infection in pregnant women with complications and its association with adverse pregnancy outcomes

Human Cytomegalovirus (HCMV) infection is associated with bad obstetric history (BOH) and adverse pregnancy outcomes (APO). Here, we characterized antiviral humoral profiles, systemic and virus specific cellular immune responses concurrently in pregnant women (n = 67) with complications including BOH and associated these signatures with pregnancy outcomes. Infection status was determined using nested blood PCR, seropositivity and IgG avidity by ELISA. Systemic and HCMV specific (pp65) cellular immune responses were evaluated by flow cytometry. Seropositivity was determined for other TORCH pathogens (n = 33) on samples with recorded pregnancy outcomes. This approach was more sensitive in detecting HCMV infection. Blood PCR positive participants, irrespective of their IgG avidity status, had higher cytotoxic potential in circulating CD8+ T cells (p < 0.05) suggesting that infection associated cellular dysfunction was uncoupled with avidity maturation of antiviral humoral responses. Also, impaired anamnestic degranulation of HCMV-pp65-specific T cells compared to HCMV blood PCR negative participants (p < 0.05) was observed. APO correlated with HCMV blood PCR positivity but not serostatus (p = 0.0039). Most HCMV IgM positive participants (5/6) were HCMV blood PCR positive with APO. None were found to be IgM positive for other TORCH pathogens. Multiple TORCH seropositivity however was significantly enriched in the APO group (p = 0.024). Generation of HCMV specific high avidity IgG antibodies had no bearing on APO (p = 0.9999). Our study highlights the utility of an integrated screening approach for antenatal HCMV infection in the context of BOH, where infection is associated with systemic and virus specific cellular immune dysfunction as well as APO.

Detection of cytomegalovirus in bronchoalveolar lavage fluid from immunocompromised patients with pneumonitis by viral culture and DNA quantification

PURPOSE

To compare the detection of human cytomegalovirus (HCMV) in bronchoalveolar lavage (BAL) fluid by viral culture and quantitative polymerase chain reaction (qPCR), and to establish a viral load threshold that can identify cases of HCMV replication indicative of pneumonitis. There is currently no universal viral load cut-off to differentiate between patients with and without pneumonitis, and the interpretation of qPCR results is challenging.

METHODS

176 consecutive BAL samples from immunosuppressed hosts with signs and/or symptoms of respiratory infection were prospectively studied by viral culture and qPCR.

RESULTS

Concordant results were obtained in 81.25% of the BAL samples. The rest were discordant, as only 34% of the qPCR-positive BAL samples were positive by culture. The median HCMV load was significantly higher in culture-positive than in culture-negative BAL samples (5,038 vs 178 IU/mL). Using a cut-off value of 1,258 IU/mL of HCMV in BAL, pneumonia was diagnosed with a sensitivity of 76%, a specificity of 100%, a VPP of 100% and VPN of 98%, and HCMV was isolated in 100% of the BAL cultures.

CONCLUSION

We found that a qPCR-negative was a quick and reliable way of ruling out HCMV pneumonitis, but a positive result did not always indicate clinically significant replication in the lung. However, an HCMV load in BAL fluid of ≥1,258 IU/mL was always associated with disease, whereas <200 IU/mL rarely so.

Quantitative PCR for the Diagnosis of HCMV Pneumonia in HSCT Recipients and Other Immunocompromised Hosts

Pneumonia is among the most serious manifestations of HCMV infection, with high morbidity and mortality. Probable pneumonia is defined as the detection of HCMV in bronchoalveolar lavage (BAL) by viral isolation or DNA quantification (qPCR) combined with symptoms and/or signs of respiratory infection. However, currently, there is no reproducible and well-defined viral load (VL) from BAL that can reliably differentiate patients with pneumonia from the much more common detection of viral DNA in seropositive patients without true HCMV pneumonia. Several studies have been published with the aim of establishing an optimal VL for differentiating pneumonia from viral lung shedding. The aim of this review is to collect and analyze the methodology and the conclusions obtained in studies whose objectives included the correlation between HCMV VL in BAL and/or the plasma and the occurrence of HCMV pneumonia. For this purpose, a total of 14 articles have been included. There are some conclusions on which they all agree. PCR techniques were more sensitive and had a higher NPV than culture techniques but were less specific and had a low PPV. The mean HCMV loads in both BAL and the plasma were significantly higher in patients with pneumonitis than in those without. The HCMV load in patients with pneumonitis was higher in BAL than in the plasma, making qPCR in BAL a better predictor of HCMV pneumonitis than in the plasma. Nevertheless, this review highlights the difficulty of establishing a universal VL value, both in BAL and in the blood, to differentiate patients with HCMV pneumonia from those without. To complete the information available in these studies, prospective multicentre studies would be required. Methodologically, a large number of patients with HCMV pneumonitis would have to be included, and a subclassification of the type of immunosuppression of each patient should be made in order to obtain an optimal VL threshold in different host groups.

Lupus Cardiomyopathy and Nephritis Associated With Adalimumab and Cytomegalovirus Infection in a Patient With Seronegative Rheumatoid Arthritis: A Case of Rhupus Syndrome

Tumor necrosis factor-alpha (TNF-α) inhibitors are associated with lupus-like disease, known as anti-TNF-α-induced lupus (ATIL). Cytomegalovirus (CMV) was reported to exacerbate lupus in the literature. To date, systemic lupus erythematosus (SLE) triggered by adalimumab in the setting of CMV infection has never been described. We present an unusual case of a 38-year-old female with a past medical history of seronegative rheumatoid arthritis (SnRA) who developed SLE associated with the use of adalimumab and CMV infection. She had severe SLE features including lupus nephritis and cardiomyopathy. The medication was discontinued. She was initiated on pulse steroid therapy and discharged with an aggressive regimen for SLE, including prednisone, mycophenolate mofetil, and hydroxychloroquine. She remained on the medications until a year later upon follow-up. ATIL from adalimumab usually manifests only mild symptoms of SLE such as arthralgia, myalgia, and pleurisy. Nephritis is very rare, and cardiomyopathy is unprecedented. Concomitant CMV infection might contribute to disease severity. Patients with SnRA may have an increased risk of developing SLE later when exposed to such medications and infection.

Correlation of cytomegalovirus viral load between whole blood and plasma of congenital cytomegalovirus infection under valganciclovir treatment

BACKGROUND

Congenital cytomegalovirus (CMV) infection (cCMV) can cause sensorineural hearing loss and neurodevelopmental disabilities in children. Oral valganciclovir (VGCV) therapy has been reported to improve long-term audiological and neurodevelopmental outcomes in patients with cCMV. The levels of CMV DNA in whole blood have been monitored in previous studies. However, quantitative methods using whole blood have not been standardized. Recently, the plasma viral load has been standardized and widely used in CMV-associated diseases.

METHODS

CMV viral loads in whole blood and plasma were serially measured in 24 patients with a confirmatory diagnosis of cCMV during oral VGCV therapy using an in-house real-time PCR assay. Plasma samples were assayed using the Cobas 6800 system (Roche Diagnostics) in addition to an in-house assay.

RESULTS

Plasma CMV viral loads were remarkably decreased at the end of therapy compared to before therapy. A significant correlation of CMV levels between whole blood and plasma was observed (Spearman's ρ = 0.566). The levels of CMV DNA before therapy were significantly correlated with the period of decreasing the viral loads to below the detection limit, not only in whole blood (Spearman's ρ = 0.901) but also in plasma (Spearman, ρ = 0.804). Finally, CMV viral loads between the in-house assay and commercially available standardized assay in 75 plasma samples with positive PCR results for CMV were compared; a significant correlation was observed between the results of both assays.

CONCLUSIONS

There was a significant correlation between the two assays (Spearman, ρ = 0.882), suggesting that CMV plasma viral loads measured by the standardized assay are widely used to monitor the levels of CMV DNA in patients with cCMV during oral VGCV therapy.

Predictive Factors of Cytomegalovirus Viremia during the Clinical Course of Anti-Neutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis: A Single Center Observational Study

We aim to elucidate factors to aid in the prediction of cytomegalovirus viremia during the treatment of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). We conducted a single-center, retrospective, observational study of 35 patients with newly diagnosed AAV. Factors associated with the development of CMV viremia were investigated via a logistic regression analysis. The CMV antigenemia test was performed in 25 patients (71%), of whom 15 (60%) were diagnosed with CMV viremia. Of these 15 patients, 5 developed a CMV infection. The total protein, hemoglobin, platelet count and lymphocyte counts at the time of the CMV antigenemia test were significantly lower in patients who developed CMV viremia. In addition, total protein, hemoglobin, platelet count and lymphocyte count also presented significantly decreasing trends in the following order: patients who did not develop CMV viremia, patients who developed CMV viremia without any symptoms, and patients who developed CMV infection. All patients with CMV recovered. In conclusion, the total protein, hemoglobin, platelet count and lymphocyte count may be useful markers for the prediction of CMV viremia and infection after the start of induction of immunosuppressive therapy for patients with AAV.

Performance Evaluation of the Fully Automated NeuMoDx RT-PCR Platform for the Quantification of CMV and EBV DNA in EDTA Plasma: Implications for Clinical Management and Establishment of a Conversion Formula

The NeuMoDx96 platform is a fully automated real-time PCR (RT-PCR) system. To provide continued testing quality with the introduction of new assays, the primary aim of this study was to evaluate the analytical and clinical performance of the NeuMoDx platform for the detection and quantification of CMV and EBV DNA in EDTA plasma. As no conversion from log₁₀ international units per milliliter to copies per milliliter was provided, the secondary aim was to calculate and establish a conversion factor for the output of results in copies per milliliter for CMV and EBV. Archived ETDA plasma samples (cytomegalovirus [CMV], n = 290; Ebstein-Barr virus [EBV], n = 254) were used to evaluate the analytical performance of the NeuMoDx96 platform against the routine real-time quantitative PCR (qPCR) assays. Additionally, the first WHO international standards (WHO-IS) for CMV (n = 70) and EBV (n = 72) were used for the calculation of the intra- and interassay variation. WHO-IS qualitative agreement between the assays was 100%. Intra-assay variability was low for both CMV assays (coefficient of variation [CV], phosphate-buffered saline [PBS], 3 log₁₀ IU/mL NeuMoDx, 3.67%; Abbott RealTime, CMV, 3.35%) and NeuMoDx EBV assay (CV, PBS, 3 log₁₀ IU/mL, 3.05%) but high for the Altona EBV assay (CV, PBS, 3 log₁₀ IU/mL, 26.13%). The overall qualitative concordance in clinical samples was 96.8% (270/279) for CMV and 96.7% (237/245) for EBV. The mean difference between the assays was -0.2 log₁₀ IU/mL (CMV) and -0.18 log₁₀ IU/mL (EBV). High qualitative concordance and a significant correlation of quantitative values for both assays make NeuMoDx CMV and EBV assays suitable for routine diagnostic testing. The new RT-PCR system and conversion formulas to report results in copies per milliliter are now applied in clinical routine testing. IMPORTANCE Clinical management of solid organ transplant (SOT) patients requires the careful monitoring of immunosuppression and viral infection or reactivation. qPCR is the gold standard for the detection and quantification of very small amounts of viral DNA and allows for an early assessment of viral load kinetics. The tested NeuMoDx 96 platform provides faster results than the previously used RT-PCR workflows for CMV (Abbott m2000 and RealTime CMV assay) and EBV (LightCycler 480 II, Roche high pure extraction, and Altona RealStar EBV assay) DNA detection. The implemented conversion formulas allow the continued reporting in clinically established copies per milliliter, important for long-term care of SOT patients.

Cytomegalovirus in the transplant setting: Where are we now and what happens next? A report from the International CMV Symposium 2021

The CMV Symposium in September 2021 was an international conference dedicated to cytomegalovirus (CMV) infection after solid organ or hematopoietic stem cell transplantation. This review provides an overview of the presentations given by the expert faculty, supplemented with educational clinical cases. Topics discussed include CMV epidemiology and diagnosis, the burden of CMV infection and disease, CMV-specific immunity and management of CMV in transplant settings. Major advances in the prevention and treatment of CMV in the past decade and increased understanding of CMV immunity have led to improved patient outcomes. In the future, management algorithms may be individualized based on the transplant recipient's immune profile, which will mark the start of a new era for patients with CMV.

An Overview of Cytomegalovirus Infection in Pregnancy

The objective of this review was to bring to attention cytomegalovirus (CMV) infection during pregnancy, taking into consideration all relevant aspects, such as maternal diagnosis, fetal infection and prevention, prenatal diagnosis, and postnatal prognosis. A literature review was performed regarding adult and congenital infection. General information regarding this viral infection and potential related medical conditions was provided, considering the issues of maternal infection during pregnancy, transmission to the fetus, and associated congenital infection management. Prenatal diagnosis includes maternal serum testing and the confirmation of the infection in amniotic fluid or fetal blood. Additionally, prenatal diagnosis requires imaging techniques, ultrasound, and complementary magnetic resonance to assess cortical and extracortical anomalies. Imaging findings can predict both fetal involvement and the postnatal prognosis of the newborn, but they are difficult to assess, even for highly trained physicians. In regard to fetal sequelae, the early diagnosis of a potential fetal infection is crucial, and methods to decrease fetal involvement should be considered. Postnatal evaluation is also important, because many newborns may be asymptomatic and clinical anomalies can be diagnosed when sequelae are permanent.

Amniotic fluid biomarkers predict the severity of congenital cytomegalovirus infection

BACKGROUNDCytomegalovirus (CMV) is the most common intrauterine infection, leading to infant brain damage. Prognostic assessment of CMV-infected fetuses has remained an ongoing challenge in prenatal care, in the absence of established prenatal biomarkers of congenital CMV (cCMV) infection severity. We aimed to identify prognostic biomarkers of cCMV-related fetal brain injury.METHODSWe performed global proteome analysis of mid-gestation amniotic fluid samples, comparing amniotic fluid of fetuses with severe cCMV with that of asymptomatic CMV-infected fetuses. The levels of selected differentially excreted proteins were further determined by specific immunoassays.RESULTSUsing unbiased proteome analysis in a discovery cohort, we identified amniotic fluid proteins related to inflammation and neurological disease pathways, which demonstrated distinct abundance in fetuses with severe cCMV. Amniotic fluid levels of 2 of these proteins - the immunomodulatory proteins retinoic acid receptor responder 2 (chemerin) and galectin-3-binding protein (Gal-3BP) - were highly predictive of the severity of cCMV in an independent validation cohort, differentiating between fetuses with severe (n = 17) and asymptomatic (n = 26) cCMV, with 100%-93.8% positive predictive value, and 92.9%-92.6% negative predictive value (for chemerin and Gal-3BP, respectively). CONCLUSIONAnalysis of chemerin and Gal-3BP levels in mid-gestation amniotic fluids could be used in the clinical setting to profoundly improve the prognostic assessment of CMV-infected fetuses.FUNDINGIsrael Science Foundation (530/18 and IPMP 3432/19); Research Fund - Hadassah Medical Organization.

Diagnosis of cytomegalovirus encephalitis using metagenomic next-generation sequencing of blood and cerebrospinal fluid: A case report

BACKGROUND

Cytomegalovirus (CMV) infections in the population are mostly subclinical, inapparent, or latent. However, it is rare in brain tissue. Most reported CMV encephalitis cases were patients with immunodeficiency. The diagnosis and detection rate of CMV encephalitis in patients with normal immune function needs to be further improved.

CASE SUMMARY

An 86-year-old male was admitted due to a sudden onset of unconsciousness for 3 h. The patient developed status epilepticus and was relieved after antiepileptic treatment. Encephalitis was considered due to the high signals of diffusion-weighted imaging sequences in the right central region by magnetic resonance imaging. Metagenomic next-generation sequencing (mNGS) of blood and cerebrospinal fluid revealed CMV, with unique reads number being 614 and 1, respectively. Simultaneous quantitative PCR results showed CMV positive in blood samples and negative in cerebrospinal fluid samples. The patient was finally diagnosed as CMV encephalitis with status epilepticus. After the antiviral, hormonal, and γ-globulin pulse therapy, the patient's condition improved, and he was finally discharged.

CONCLUSION

mNGS could be a reliable approach for the diagnosis of CMV encephalitis, with high efficiency, sensitivity, and specificity.

Docosahexaenoic acid supplementation represses the early immune response against murine cytomegalovirus but enhances NK cell effector function

BACKGROUND

Docosahexaenoic acid (DHA) supplementation is beneficial for several chronic diseases; however, its effect on immune regulation is still debated. Given the prevalence of cytomegalovirus (CMV) infection and because natural killer (NK) cells are a component of innate immunity critical for controlling CMV infection, the current study explored the effect of a DHA-enriched diet on susceptibility to murine (M) CMV infection and the NK cell effector response to MCMV infection.

RESULTS

Male C57BL/6 mice fed a control or DHA-enriched diet for 3 weeks were infected with MCMV and sacrificed at the indicated time points postinfection. Compared with control mice, DHA-fed mice had higher liver and spleen viral loads at day 7 postinfection, but final MCMV clearance was not affected. The total numbers of NK cells and their terminal mature cell subset (KLRG1+ and Ly49H+ NK cells) were reduced compared with those in control mice at day 7 postinfection but not day 21. DHA feeding resulted in higher IFN-γ and granzyme B expression in splenic NK cells at day 7 postinfection. A mechanistic analysis showed that the splenic NK cells of DHA-fed mice had enhanced glucose uptake, increased CD71 and CD98 expression, and higher mitochondrial mass than control mice. In addition, DHA-fed mice showed reductions in the total numbers and activation levels of CD4+ and CD8+ T cells.

CONCLUSIONS

These results suggest that DHA supplementation represses the early response to CMV infection but preserves NK cell effector functions by improving mitochondrial activity, which may play critical roles in subsequent MCMV clearance.

Laboratory diagnostic testing for cytomegalovirus infection in solid organ transplant patients

Human cytomegalovirus (CMV) infection, which is one of the most common complications in transplant recipients, increases the risk of graft loss and rejection. Laboratory strategies for diagnosing CMV infection rely on the measurement of viral DNAemia and CMV-specific cell-mediated immunity (CMV-CMI). The CMV quantitative nucleic acid amplification test (QNAT) enabled the spread of preemptive therapy and prompted recommendations for surveillance, diagnosis, and monitoring. Despite the implementation of the World Health Organization international standard for calibration, variability of QNAT persists due to technical issues. CMV immunoglobulin G serology is the standard method for CMV immune screening of transplant candidates and donors. Assays for CMV-CMI play an important role in helping to predict the risk and to develop an individualized CMV management plan. Genotypic testing for resistance is needed when drug-resistant CMV infection is suspected. Here, we review the state of the art of laboratory tests for CMV infection in solid organ transplantation.

Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition)

The third edition of Flow Cytometry Guidelines provides the key aspects to consider when performing flow cytometry experiments and includes comprehensive sections describing phenotypes and functional assays of all major human and murine immune cell subsets. Notably, the Guidelines contain helpful tables highlighting phenotypes and key differences between human and murine cells. Another useful feature of this edition is the flow cytometry analysis of clinical samples with examples of flow cytometry applications in the context of autoimmune diseases, cancers as well as acute and chronic infectious diseases. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid. All sections are written and peer-reviewed by leading flow cytometry experts and immunologists, making this edition an essential and state-of-the-art handbook for basic and clinical researchers.

Long-Term Evolution of the Adaptive NKG2C+ NK Cell Response to Cytomegalovirus Infection in Kidney Transplantation: An Insight on the Diversity of Host-Pathogen Interaction

Human CMV infection is frequent in kidney transplant recipients (KTR). Pretransplant Ag-specific T cells and adaptive NKG2C⁺ NK cells associate with reduced incidence of infection in CMV⁺ KTR. Expansions of adaptive NKG2C⁺ NK cells were reported in posttransplant CMV-infected KTR. To further explore this issue, NKG2C⁺ NK, CD8⁺, and TcRγδ T cells were analyzed pretransplant and at different time points posttransplant for ≥24 mo in a cohort of CMV⁺ KTR (n = 112), stratified according to CMV viremia detection. In cryopreserved samples from a subgroup (n = 49), adaptive NKG2C⁺ NK cell markers and T cell subsets were compared after a longer follow-up (median, 56 mo), assessing the frequencies of CMV-specific T cells and viremia at the last time point. Increased proportions of NKG2C⁺ NK, CD8⁺, and TcRγδ T cells were detected along posttransplant evolution in viremia(+) KTR. However, the individual magnitude and kinetics of the NKG2C⁺ NK response was variable and only exceptionally detected among viremia(-) KTR, presumably reflecting subclinical viral replication events. NKG2C⁺ expansions were independent of KLRC2 zygosity and associated with higher viral loads at diagnosis; no relation with other clinical parameters was perceived. Increased proportions of adaptive NKG2C⁺ NK cells (CD57⁺, ILT2⁺, FcεRIγ^-) were observed after resolution of viremia long-term posttransplant, coinciding with increased CD8⁺ and Vδ2^- γδ T cells; at that stage CMV-specific T cells were comparable to viremia(-) cases. These data suggest that adaptive NKG2C⁺ NK cells participate with T cells to restore CMV replication control, although their relative contribution cannot be discerned.

Congenital Human Cytomegalovirus Infection: A Narrative Review of Maternal Immune Response and Diagnosis in View of the Development of a Vaccine and Prevention of Primary and Non-Primary Infections in Pregnancy

Congenital cytomegalovirus infection (cCMV) may affect about 1% of all newborns all over the world as a result of either a primary or recurrent human cytomegalovirus (HCMV) infection. While about 90% of infants affected by cCMV are asymptomatic at birth, the remaining 10% are symptomatic often with neurodevelopmental impairment and sensorineural hearing loss. In view of identifying the best approach to vaccine prevention of cCMV, this review will examine the most important steps made in the study of the immune response to, and diagnosis of, HCMV infection. The maternal immune response and immune correlates of protection are being partially identified with a partial contribution given by our laboratory. The diagnosis of primary infection is often difficult to achieve in the first three months of pregnancy, which is the time primarily involved in virus transmission to the fetus in association with the most severe symptoms and sequelae. Prevention of cCMV is anticipated by prevention of primary infection in early pregnancy by means of different measures, such as (i) behavioral-educational measures, (ii) immunoglobulin administration, (iii) antiviral treatment with valaciclovir. However, the most promising approach to cCMV prevention appears to be the development of a non-living vaccine, including at least three viral antigens: gB, pentamer complex gHgLpUL128L, and pp65, which have been shown to be able to stimulate both the humoral and the cellular arms of the maternal immune response. Primary HCMV infection may be managed in pregnancy by counseling of the couples involved by a team of specialists that includes virologists, obstetricians, infectivologists and neonatologists.

Interleukin-18 and tumor necrosis factor-α are elevated in solid organ transplant recipients with possible cytomegalovirus end-organ disease

End-organ cytomegalovirus (CMV) disease can be life threatening to solid organ transplant recipients. Diagnosis is often complicated by variation in amount of CMV DNA in plasma and the need for an invasive procedure to obtain a biopsy of the suspected affected organ, which can delay recognition and treatment. Several inflammatory cytokines are elevated in CMV disease, and the purpose of this study was to determine if they could be used to distinguish solid organ transplant recipients with CMV DNAemia alone from those with possible end-organ CMV disease. We found that regardless of pre-transplant CMV serostatus, plasma interleukin (IL)-18, tumor necrosis factor-α (TNF-α), and amount of CMV DNA in plasma were increased in possible end-organ CMV disease, with elevated IL-18 associated with increased odds of possible end-organ CMV disease even after adjusting for amount of CMV DNA. These findings highlight IL-18 and TNF-α as potential non-invasive markers of possible end-organ CMV disease regardless of transplanted organ or serostatus in solid organ transplant recipients.

CMV Infection in Hematopoietic Stem Cell Transplantation: Prevention and Treatment Strategies

Purpose of Review

Cytomegalovirus (CMV) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (Allo-HSCT). New strategies and methods for prevention and management of CMV infection are urgently needed. We aim to review the new developments in diagnostics, prevention, and management strategies of CMV infection in Allo-HSCT recipients.

Recent Findings

The approval of the novel anti-CMV drug letermovir in 2017 has led to an increase in the use of antiviral prophylaxis as a preferred approach for prevention in many centers. Real-world studies have shown efficacy similar to the clinical trial. CMV-specific T cell-mediated immunity assays identify patients with immune reconstitution and predict disease progression. Phase 2 trials of maribavir have shown its efficacy as preemptive therapy and treatment of resistant and refractory CMV infections. Adoptive T cell therapy is an emerging option for treatment of refractory and resistant CMV. Of the different CMV vaccine trials, PepVax has shown promising results in a phase 1 trial.

Summary

CMV cell-mediated immunity assays have potential to be used as an adjunctive test to develop individualized management plan by identifying the patients who develop immune reconstitution; however, further prospective interventional studies are needed. Maribavir and adoptive T cell therapy are promising new therapies for treatment of CMV infections. CMV vaccine trials for prevention are also under way.

A Novel Multiplexed Enzyme-Linked Immunosorbent Assay for the Detection of IgG Seroreactivity to Cytomegalovirus (CMV) UL144

Infection with human cytomegalovirus (CMV) is common and may have grave consequences in transplant recipients and congenitally infected children. Diagnosis of CMV infection is based on detection of specific antibodies and molecular assays. The incorporation of CMV serological assays into diagnostic algorithms requires careful evaluation and interpretation. Very few serological assays measure CMV infection by a specific strain. We developed an enzyme-linked immunosorbent assay (ELISA) using CMV-encoded UL144 as the antigen. UL144 encodes three major genotypes, A, B, and C, and recombinants. The ELISA was developed with the three UL144 proteins and optimized as a multiplex assay. Sera from 55 positive and 59 negative CMV IgG, determined by the clinical microbiology laboratory, were used for evaluation and optimization. A cutoff optical density (OD) that distinguishes UL144 antibody-positive from antibody-negative sera was established. UL144 A, B, C, and combinations of these antigens were detected in sera. An assay threshold of 0.1 was established and, from a total of 303 sera, the overall sensitivity, specificity, and positive and negative predictive values of the multiplex ELISA were 86.72% (95% confidence interval [CI] 79.59% to 92.07%), 96.57% (92.69% to 98.73%), 94.40% (88.45% to 97.38%), and 91.60% (87.50% to 94.44%), respectively. The inter- and intraassay median coefficients of variation were 0.06 (interquartile range [IQR] 0.56, 0.2) and 0.171 (IQR 0.038, 0.302), respectively. No cross-reactivity was observed with HSV-positive CMV-negative sera. This ELISA gives simple and reproducible results for detection of anti-CMV UL144 IgG. It may assist in differentiating natural infection from CMV vaccines that lack UL144, and may provide an important tool for epidemiological studies of CMV strains.

Detection of Human Cytomegalovirus Proteins in Paraffin-Embedded Breast Cancer Tissue Specimens-A Novel, Automated Immunohistochemical Staining Protocol

Emerging evidence supports a significant association between human cytomegalovirus (HCMV) and human malignancies, suggesting HCMV as a human oncomodulatory virus. HCMV gene products are found in >90% of breast cancer tumors and seem to be correlated with more aggressive disease. The definitive diagnosis of HCMV relies on identification of virus inclusions and/or viral proteins by different techniques including immunohistochemical staining. In order to reduce biases and improve clinical value of HCMV diagnostics in oncological pathology, automation of the procedure is needed and this was the purpose of this study. Tumor specimens from 115 patients treated for primary breast cancer at Akershus University Hospital in Norway were available for the validation of the staining method in this retrospective study. We demonstrate that our method is highly sensitive and delivers excellent reproducibility for staining of HCMV late antigen (LA), which makes this method useful for future routine diagnostics and scientific applications.

Is it time to adopt routine cytomegalovirus screening in pregnancy? No!

Congenital cytomegalovirus is caused by maternal primary or nonprimary infection during pregnancy and is a major preventable cause of neurodisability. The proposed strategies to reduce congenital cytomegalovirus include primary prevention with maternal hygiene measures and secondary prevention by serologic screening for detecting maternal primary infection. A recent randomized trial found that high-dose valaciclovir treatment resulted in a significant reduction in fetal infection after first-trimester maternal primary infection, leading to calls to start routine serologic screening in pregnancy. Previously, observational studies have found a reduction in fetal infection with after maternal primary cytomegalovirus infection when hyperimmune globulin is administered twice weekly during the first trimester of pregnancy; however, this has not been replicated in randomized trials that have used different regimens. Furthermore, some evidence from a single intervention trial and observational studies do not provide us with the necessary data required for rolling out an appropriate screening program. All screening tests may be associated with harm; in the case of congenital cytomegalovirus, there is the well-recognized potential for increasing terminations of pregnancy without diagnostic confirmation of fetal infection or sequelae. Although valaciclovir and hyperimmune globulin treatments may significantly reduce fetal infection rates, they do not prevent severe cytomegalovirus-related fetal brain damage in all pregnancies. Therefore, it is not clear that the offer of a prenatal intervention will provide sufficient reassurance to screen-positive women. In addition, the effectiveness of a prenatal screening and treatment strategy is predicated on a high rate of maternal primary infection, which is limited to regions with low cytomegalovirus seroprevalence, such as Western Europe. In some countries, such as the United States, Finland, and Brazil, nonprimary maternal infections are responsible for most congenital cytomegalovirus health burdens, limiting the potential impact of pregnancy screening. In this invited clinical perspective, we reviewed the evidence and outlined the steps needed to be taken before determining whether the benefits of routine screening for cytomegalovirus in pregnancy outweigh the harms. Until we have the necessary evidence, we should follow the current advice of multiple national health authorities and focus on promoting primary prevention through maternal hygiene precautions.

Pitfalls in the Serological Diagnosis of Primary Human Cytomegalovirus Infection in Pregnancy Due to Different Kinetics of IgM Clearance and IgG Avidity Index Maturation

Primary infection occurs when seronegative women are infected by human cytomegalovirus (HCMV). Diagnosis of primary infection is based on the following: antibody seroconversion, presence of IgM and low IgG avidity index (AI), and presence of DNAemia. The kinetics of HCMV-specific IgM antibody and maturation of AI might be very rapid or long-lasting during primary infection, which makes serological diagnosis insidious. The aims of this study were as follows: (i) to report atypical kinetics of HCMV-specific IgM antibody and AI early after onset of primary HCMV infection in a population of pregnant women, and (ii) to assess the frequency of such results. Altogether, 1309 sequential serum samples collected from 465 pregnant women with primary HCMV infection were included in the study. As a general rule, using the LIAISON^®CMVIgMII and LIAISON^®CMVIgGAvidityII assays, virus-specific IgM antibody levels decreased, while IgG AI increased over time during the first three months after infection onset. However, early clearance of IgM antibody and/or early IgG AI maturation occurred in 46/426 (10.7%) women. In more details, 20/426 (4.7%) and 26/418 (6.2%) women had undetectable IgM antibody or high IgG AI, respectively, when tested within 1-3 months after well-defined infection onset. Twenty sera from as many women with high IgG AI by the LIAISON assay were further tested for IgG AI by VIDAS^®CMVIgGAvidityII and Mikrogen recomLineCMVIgG Avidity assays. Comparable results were obtained with VIDAS, whereas 14/20 sera gave low AI with the Mikrogen assay. In conclusion, about 11% of pregnant women undergoing a primary HCMV infection showed misleading serological results. Additional and appropriate testing might help in reducing the risk of missing HCMV primary infection in pregnancy. Furthermore, preconceptional testing should be strongly recommended.

Betaherpesvirus assembly and egress: Recent advances illuminate the path

The human betaherpesviruses, human cytomegalovirus (HCMV; species Human betaherpesvirus 5) and human herpesviruses 6A, 6B, and 7 (HHV-6A, -6B, and -7; species Human betaherpesviruses 6A, 6B, and 7) are highly prevalent and can cause severe disease in immune-compromised and immune-naive populations in well- and under-developed communities. Herpesvirus virion assembly is an intricate process that requires viral orchestration of host systems. In this review, we describe recent advances in some of the many cellular events relevant to assembly and egress of betaherpesvirus virions. These include modifications of host metabolic, immune, and autophagic/recycling systems. In addition, we discuss unique aspects of betaherpesvirus virion structure, virion assembly, and the cellular pathways employed during virion egress.