Passive immunization during pregnancy for congenital cytomegalovirus infection

Ophthalmic Complications, Diagnosis, and Treatment of Congenital Human Cytomegalovirus Infection

Background: Human cytomegalovirus (hCMV) is the most common etiological agent of congenital infections seen in newborns. Among the most commonly observed complications in children with congenital human cytomegalovirus infection are those affecting the visual system. Ocular complications of congenital CMV (cCMV) are a topic rarely addressed in the literature, which prompted the authors to update the available knowledge with the latest data. Methodology: English-language literature published between April 2000 and November 2023 (PubMed, NIH, Google Scholar) was analyzed for ocular complications of cCMV. The data obtained were categorized according to the ocular area involved and the incidence. A compilation of criteria for the symptomatic form of cCMV was also created. Results: The cCMV complications described in the literature affect all parts of the visual system: the anterior segment, the posterior segment, the posterior visual pathways, and the visual cortex. The most commonly described ocular complication of cCMV is choroidal and retinal scarring. Conclusions: Ophthalmic complications of cCMV can cause severe visual disturbances. Ophthalmic diagnosis in newborns should include hCMV PCR testing, which has the highest sensitivity and specificity. In the symptomatic form of cCMV, treatment should be instituted according to recommendations. A consensus should be established for screening of primary hCMV infection in pregnant women, the way in which to define the symptomatic form of cCMV, and the appropriateness and standards of treatment for primary hCMV infection in pregnant women.

Evaluation of Congenital Cytomegalovirus Infection in Pregnant Women Admitted to a University Hospital in Istanbul

Cytomegalovirus (CMV) can cause serious complications in immunocompromised individuals and fetuses with congenital infections. These can include neurodevelopmental impairments and congenital abnormalities in newborns. This paper emphasizes the importance of concurrently evaluating ultrasonography findings and laboratory parameters in diagnosing congenital CMV infection. To examine the prenatal characteristics of CMV DNA-positive patients, we assessed serum and amniotic fluid from 141 pregnant women aged 19-45 years, each with fetal anomalies. ELISA and PCR tests, conducted in response to these amniocentesis findings, were performed at an average gestational age of 25 weeks. Serological tests revealed that all 141 women were CMV IgG-positive, and 2 (1.41%) had low-avidity CMV IgG, suggesting a recent infection. CMV DNA was detected in 17 (12.05%) amniotic fluid samples using quantitative PCR. Of these, 82% exhibited central nervous system abnormalities. Given that most infections in pregnant women are undetectable and indicators non-specific, diagnosing primary CMV in pregnant women using clinical findings alone is challenging. We contend that serological tests should not be the sole means of diagnosing congenital CMV infection during pregnancy.

Hygiene-based measures for the prevention of cytomegalovirus infection in pregnant women: a systematic review

BACKGROUND

Human Cytomegalovirus (HCMV) is the most frequent congenital infection worldwide causing important sequelae. However, no vaccine or antiviral treatments are currently available, thus interventions are restricted to behavioral measures. The aim of this systematic review was to assess evidence from available intervention studies using hygiene-based measures to prevent HCMV infection during pregnancy.

METHODS

Studies published from 1972 to 2023 were searched in Medline, PsycInfo, and Clinical Trials (PROSPERO, CRD42022344840) according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Methodological quality was assessed by two authors, using ROBE-2 and MINORS.

RESULTS

After reviewing 6 selected articles, the outcome analysis suggested that implementation of hygiene-based interventions during pregnancy prevent, to some extent, the acquisition of congenital HCMV.

CONCLUSIONS

However, these conclusions are based on limited and low-quality evidence available from few studies using this type of intervention in clinical practice. Thus, it would be necessary to perform effective and homogeneous intervention studies using hygiene-based measures, evaluated in high-quality randomized controlled trials (RCTs).

Decidual-tissue-resident memory T cells protect against nonprimary human cytomegalovirus infection at the maternal-fetal interface

Congenital cytomegalovirus (cCMV) is the most common intrauterine infection, leading to infant neurodevelopmental disabilities. An improved knowledge of correlates of protection against cCMV is needed to guide prevention strategies. Here, we employ an ex vivo model of human CMV (HCMV) infection in decidual tissues of women with and without preconception immunity against CMV, recapitulating nonprimary vs. primary infection at the authentic maternofetal transmission site. We show that decidual tissues of women with preconception immunity against CMV exhibit intrinsic resistance to HCMV, mounting a rapid activation of tissue-resident memory CD8+ and CD4+ T cells upon HCMV reinfection. We further reveal the role of HCMV-specific decidual-tissue-resident CD8+ T cells in local protection against nonprimary HCMV infection. The findings could inform the development of a vaccine against cCMV and provide insights for further studies of the integrity of immune defense against HCMV and other pathogens at the human maternal-fetal interface.

Early detection of active Human CytomegaloVirus (hCMV) infection in pregnant women using data generated for noninvasive fetal aneuploidy testing

BACKGROUND

Prenatal hCMV infections can lead to severe embryopathy and neurological sequelae in neonates. Screening during pregnancy is not recommended by global societies, as there is no effective therapy. Recently, several groups showed that maternal-fetal hCMV transmission can be strongly reduced by administering anti-viral agents early in pregnancy. This calls for a screening method to identify at risk pregnancies at an appropriate gestational age, with the possibility for large-scale enrolment. Non-Invasive Prenatal Testing (NIPT) for fetal aneuploidy screening early in pregnancy is already implemented in many countries and performed on a large-scale basis. We investigated the use of whole genome cell-free DNA (cfDNA) sequencing data, generated for the purpose of NIPT, as (pre-)screening tool to identify women with active hCMV-infections, eligible for therapy.

METHODS

Coded raw sequencing NIPT data from 204,818 pregnant women from three testing laboratories were analyzed for the presence of hCMV-cfDNA. Samples were stratified by cfDNA-hCMV load. For validation and interpretation, diagnostic hCMV-qPCR and serology testing were performed on a subset of cfDNA-hCMV-positive (n = 112) and -negative (n = 127) samples.

FINDINGS

In 1930 samples (0.94%) hCMV fragments were detected. Validation by hCMV-qPCR showed that samples with high cfDNA-hCMV load tested positive and cfDNA-hCMV-negative samples tested negative. In 32/112 cfDNA-hCMV-positive samples (28.6%) the serological profile suggested a recent primary infection: this was more likely in samples with high cfDNA-hCMV load (78.6%) than in samples with low cfDNA-hCMV load (11.0%). In none of the cfDNA-hCMV-negative samples serology was indicative of a recent primary infection.

INTERPRETATION

Our study shows that large-scale (pre-)screening for both genetic fetal aberrations and active maternal hCMV infections during pregnancy can be combined in one cfDNA sequencing test, performed on a single blood sample, drawn in the first trimester of pregnancy.

FUNDING

This work was partly funded by the Prenatal Screening Foundation Nijmegen, the Netherlands.

Congenital cytomegalovirus infection: the state of the art and future perspectives

Congenital cytomegalovirus (cCMV) infection is the most common congenital infection, with an estimated incidence of approximately one in 200 infants in high-income settings. Approximately one in four children may experience life-long consequences, including sensorineural hearing loss and neurodisability. Knowledge regarding prevention, diagnosis, and treatment increased in the recent years, but some challenges remain. In this review, we tried to summarize the current knowledge on both the obstetrical and pediatric areas, while also highlighting controversial aspects and future perspectives. There is a need to enhance awareness among the general population and pregnant women through specific information programs. Further research is needed to better define the classification of individuals at birth and to have a deeper understanding of the long-term outcomes for so defined children. Finally, the availability of valaciclovir medication throughout pregnancy, where appropriate, has prompted the assessment of a universal serological antenatal screening. It is recommended to establish a dedicated unit for better evaluation and management of both mothers and children.

Single-cell analysis of memory B cells from top neutralizers reveals multiple sites of vulnerability within HCMV Trimer and Pentamer

Human cytomegalovirus (HCMV) can cause severe diseases in fetuses, newborns, and immunocompromised individuals. Currently, no vaccines are approved, and treatment options are limited. Here, we analyzed the human B cell response of four HCMV top neutralizers from a cohort of 9,000 individuals. By single-cell analyses of memory B cells targeting the pentameric and trimeric HCMV surface complexes, we identified vulnerable sites on the shared gH/gL subunits as well as complex-specific subunits UL128/130/131A and gO. Using high-resolution cryogenic electron microscopy, we revealed the structural basis of the neutralization mechanisms of antibodies targeting various binding sites. Moreover, we identified highly potent antibodies that neutralized a broad spectrum of HCMV strains, including primary clinical isolates, that outperform known antibodies used in clinical trials. Our study provides a deep understanding of the mechanisms of HCMV neutralization and identifies promising antibody candidates to prevent and treat HCMV infection.

Cytomegalovirus infection during pregnancy

Cytomegalovirus (CMV) infection during pregnancy is a global silent problem. Additionally, it is the leading cause of congenital infections, non-genetic sensorineural hearing loss, and neurodevelopmental delays in infants. However, this has barely been recognized globally. This condition lacks adequate attention, which is further emphasized by the lack of awareness among healthcare workers and the general population. The impact of CMV infection is often overlooked because of the asymptomatic nature of its presentation in infected pregnant women and newborns, difficulty in diagnosis, and the perception that infants born to women with pre-existing antibodies against CMV have normal neonatal outcomes. This article highlights the latest information on the epidemiology, transmission, clinical manifestations, and development of CMV infection and its management. We reviewed the pathophysiology and clinical manifestations of CMV infection in pregnant women, diagnostic methods, including screening and prognostic markers, and updates in treatment modalities. Current advancements in research on vaccination and hyperimmunoglobulins with worldwide treatment protocols are highlighted.

Biweekly Versus Monthly Hyperimmune Globulin Therapy for Primary Cytomegalovirus Infection in Pregnancy

Primary cytomegalovirus (CMV) infection during pregnancy is associated with an increased risk of congenital CMV (cCMV). Hyperimmune globulin (HIG) therapy has been proposed as a potential prophylaxis to reduce maternal-fetal transmission. Data on whether the administration of HIG every 2 weeks offers benefits over HIG administration every 4 weeks are lacking. This was a retrospective analysis including pregnant women with primary CMV infection diagnosed in the first or early second trimester between 2010 and 2022 treated with HIG every 4 weeks (300 IE HIG per kg) or every 2 weeks (200 IE HIG per kg), respectively. In total, 36 women (4 weeks: n = 26; 2 weeks: n = 10) and 39 newborns (4 weeks: n = 29; 2 weeks: n = 10) were included. The median gestational age at the first HIG administration was 13.1 weeks. There was no significant difference in the cCMV rates between the women who received HIG every 4 versus every 2 weeks (n = 8/24 [33.3%] vs. 3/10 [30.0%]; p = 0.850). An abnormal fetal ultrasound was present in three fetuses and fetal magnetic resonance imaging (MRI) anomalies in four fetuses were related to cCMV infection, with no significant difference in the frequency between the two groups. A larger study will be needed to determine whether HIG administration every 2 instead of every 4 weeks improves the maternal-fetal transmission rates.

Cytomegalovirus Infection in Pregnancy Prevention and Treatment Options: A Systematic Review and Meta-Analysis

OBJECTIVES

Cytomegalovirus (CMV) infection is a significant health concern affecting numerous expectant mothers across the globe. CMV is the leading cause of health problems and developmental delays among infected infants. Notably, this study examines CMV infection in pregnancy, its management, prevention mechanisms, and treatment options.

METHODS

Specifically, information from the Cochrane Library, PUBMED, Wiley Online, Science Direct, and Taylor Francis databases were reviewed along with additional records identified through the register, the Google Scholar search engine. Based on the search, 21 articles were identified for systematic review.

RESULTS

A total of six randomized controlled trials (RCTs) were utilized for a meta-analytic review. As heterogeneity was substantial, the random effects model was used for meta-analysis. Utilizing the random-effects model, the restricted maximum likelihood (REML) approach, the estimate of effect size (d = -0.479, 95% CI = -0.977 to 0.019, p = 0.060) suggests the results are not statistically significant, so it cannot be inferred that the prevention methods used were effective, despite an inverse relationship between treatment and number of infected cases. The findings indicated that several techniques are used to prevent, diagnose, and manage CMV infection during pregnancy, including proper hygiene, ultrasound examination (US), magnetic resonance imaging (MRI), amniocentesis, viremia, hyperimmunoglobulin (HIG), and valacyclovir (VACV).

CONCLUSIONS

The current review has significant implications for addressing CMV infection in pregnancy. Specifically, it provides valuable findings on contemporary management interventions to prevent and treat CMV infection among expectant mothers. Therefore, it allows relevant stakeholders to address these critical health concerns and understand the effectiveness of the proposed prevention and treatment options.

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.

Mathematical Modeling of Rhesus Cytomegalovirus Transplacental Transmission in Seronegative Rhesus Macaques

Approximately 0.7% of infants are born with congenital cytomegalovirus (CMV), making it the most common congenital infection. About 1 in 5 congenitally infected babies will suffer long-term sequelae, including sensorineural deafness, intellectual disability, and epilepsy. CMV infection is highly species-dependent, and the rhesus CMV (RhCMV) infection of rhesus monkey fetuses is the only animal model that replicates essential features of congenital CMV (cCMV) infection in humans, including placental transmission, fetal disease, and fetal loss. Using experimental data from RhCMV seronegative rhesus macaques inoculated with RhCMV in the late first to early second trimesters of pregnancy, we built and calibrated a mathematical model for the placental transmission of CMV. The model was then used to study the effect of the timing of inoculation, maternal immune suppression, and hyper-immune globulin infusion on the risk of placental transmission in the context of primary and reactivated chronic maternal CMV infection.

Universal screening programme for cytomegalovirus infection in the first trimester of pregnancy: study protocol for an observational multicentre study in the area of Barcelona (CITEMB study)

INTRODUCTION

Congenital cytomegalovirus (cCMV) is the leading cause of non-genetic sensorineural hearing loss and one of the main causes of neurological disability. Despite this, no universal screening programme for cCMV has been implemented in Spain. A recent study has shown that early treatment with valaciclovir, initiated in the first trimester and before the onset of signs in the fetus, reduces the risk of fetal infection. This finding favours the implementation of a universal screening programme for cCMV.The aim of this study is to evaluate the performance of a universal screening programme for cCMV during the first trimester of pregnancy in a primary care setting.

METHODS AND ANALYSIS

This is an observational multicentre cohort study. The study will be conducted in four primary care settings from the Northern Metropolitan Barcelona area and three related hospitals and will last 3 years and will consist of a recruitment period of 18 months.In their first pregnancy visit, pregnant women will be offered to add a CMV serology test to the first trimester screening tests. Pregnant women with primary infection will be referred to the reference hospital, where they will continue treatment and follow-up according to the clinical protocol of the referral hospital, which includes treatment with valacyclovir. A CMV-PCR will be performed at birth on newborns of mothers with primary infection, and those who are infected will undergo neonatal follow-up for at least 12 months of life.For the analysis, the acceptance rate, the prevalence of primary CMV infections and the CMV seroprevalence in the first trimester of pregnancy will be studied.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the University Institute Foundation for Primary Health Care Research Jordi Gol i Gurina Ethics Committee 22/097-P dated 27 April 2022.

New therapeutic perspective in the prevention of congenital cytomegalovirus infection

INTRODUCTION

Hyperimmune globulin Cytotect CP® is a candidate for cytomegalovirus congenital infection prevention. We previously demonstrated its efficacy to prevent villi infection in our first-trimester placenta explants up to day 7, but with an inefficiency at day 14 (Coste-Mazeau et al., Microorganisms, 2021). As this could impact clinical efficacy, we now study the effect of weekly administration of Cytotect CP® on the prevention of villi infection.

METHODS

Human embryonic lung fibroblast cells were infected at confluence with the endothelial strain TB40/E. Placentae were collected from voluntary pregnancy terminations (8-14 weeks of gestation) from cytomegalovirus-seronegative women. After 5 days of infection of the cells, villi explants were simultaneously added on sponges with Cytotect CP® at various concentrations. After 7 days, Cytotect CP® was renewed in only half of the plates. Villi were collected at days 7 and 14 with or without medium renewal. We compared the viral load by duplex quantitative PCR cytomegalovirus/albumin and the toxicity by measuring β-hCG concentrations in the supernatants with and without medium renewal.

RESULTS

We did not find any efficacy of Cytotect CP® at day 14 when Cytotect CP® is not renewed, but a regular decrease of the viral load when the immunoglobulins were renewed at day 7, with an EC50 = 0.52 U/mL. We did not observed toxicity of Cytotect CP® with or without renewal of the molecule.

CONCLUSION

Cytotect CP® is more effective when renewed at day 7. The prevention of congenital cytomegalovirus infection could be enhanced by reducing the spacing of doses.

Prevention of Congenital Cytomegalovirus Infection: Review and Case Series of Valaciclovir versus Hyperimmune Globulin Therapy

Cytomegalovirus (CMV) is the most common cause of congenital infections in developed countries because is capable of infecting the fetus after both primary and recurrent maternal infection, and because the virus may be spread for years through infected children. Moreover, CMV is the most serious congenital infection associated with severe neurological and sensorineural sequelae, which can occur at birth or develop later on. Hygienic measures can prevent CMV transmission, which mainly involve contact with children under 3 years of age and attending a nursery or daycare. In animal and human pregnancies, many observational and controlled studies have shown that CMV-specific hyperimmune globulin (HIG) is safe and can significantly decrease maternal-fetal transmission of CMV infection and, mostly, the occurrence of CMV disease. Recently, valaciclovir at the dosage of 8 g/day was also reported to be capable of decreasing the rates of congenital infection and disease. However, comparing the results of our two recent case series, the infants born to women treated with HIG showed significantly lower rates of CMV DNA positivity in urine (9.7% vs. 75.0%; p < 0.0001) and abnormalities after follow-up (0.0% vs. 41.7%; p < 0.0001). The implementation of CMV screening would enable primary prevention via hygiene counseling, improve the understanding and awareness of congenital CMV infection, and increase the knowledge of the potential efficacy of preventive or therapeutic HIG or antiviral administration.

Cytomegalovirus in Pregnancy

Cytomegalovirus is a pervasive DNA herpesvirus that, while clinically insignificant to an immunocompetent adult host, can cause significant morbidity to a congenitally infected fetus. Although detection is often possible with several common ultrasonographic markers and good diagnostic accuracy using polymerase chain reaction testing of amniotic fluid, there are no proven prenatal prevention or antenatal treatment options. Therefore, universal screening is not currently recommended in pregnancy. Strategies that have been studied in the past include immunoglobulins, antivirals, and the development of a vaccine. In this review, we will further discuss the themes above, along with future direction for prevention and treatment.

ADCC-activating antibodies correlate with protection against congenital human cytomegalovirus infection

Human cytomegalovirus (HCMV) is the most common vertically transmitted infection worldwide, yet there are no licensed vaccines or therapeutics to prevent congenital HCMV (cCMV) infection. Emerging evidence from studies of natural infection and HCMV vaccine trials indicates that antibody Fc effector functions may defend against HCMV infection. We previously reported that antibody-dependent cellular phagocytosis (ADCP) and IgG activation of FcγRI/FcγRII were associated with reduced risk of cCMV transmission, leading us to hypothesize that other Fc-mediated antibody functions may also contribute to protection. In this same cohort of HCMV transmitting (n = 41) and non-transmitting (n = 40) mother-infant dyads, we found that higher maternal sera antibody-dependent cellular cytotoxicity (ADCC) activation was also associated with decreased risk of cCMV infection. We determined that NK cell-mediated ADCC responses correlated strongly with anti-HCMV IgG FcγRIII/CD16 activation and IgG binding to the HCMV immunoevasin protein UL16. Notably, anti-UL16 IgG binding and engagement of FcγRIII/CD16 were higher in non-transmitting versus transmitting dyads and interacted significantly with ADCC responses. These findings indicate that ADCC-activating antibodies against novel targets such as UL16 may represent an important protective maternal immune response against cCMV infection, which can guide future HCMV correlates studies and vaccine development.

An Overview of Antiviral Treatments in Pregnancy

Viral infections pose unique threats to pregnant persons and their infants. As the frequency of epidemics caused by novel pathogens increases, understanding pregnancy-specific considerations for antiviral treatments is critical for obstetric and nonobstetric providers alike. The use of pharmacologic therapeutics in pregnancy, which include antivirals, pathogen-specific antibodies, and vaccines, is limited due to the lack of purposeful, methodologic, pharmacometrics analyses in this special population. Our current understanding regarding dosing, safety, and efficacy stems from our knowledge of potential maternal or neonatal risks, observational data, and rarely clinical trials. In this review, we provide an overview on the use of antivirals during pregnancy.

Maternal antibodies induced by a live attenuated vaccine protect neonatal mice from cytomegalovirus

Human cytomegalovirus (HCMV) frequently causes congenital infections, resulting in birth defects and developmental disorders. A vaccine is needed, but unavailable. We analyzed the potential of CMV mutants, lacking their STAT2 antagonists to serve as live attenuated vaccine viruses in mice. Infections with attenuated viruses elicited strong ELISA-reactive binding IgG responses and induced neutralizing antibodies as well as antibodies stimulating cellular Fcγ receptors, including the antibody-dependent cellular cytotoxicity (ADCC)-eliciting receptors FcγRIII/CD16 and FcγRIV. Accordingly, vaccinated mice were fully protected against challenge infections. Female mice vaccinated prior to gestation transmitted CMV-specific IgG to their offspring, which protected the progeny from perinatal infections in a mouse model for congenital CMV disease. To define the role of maternal antibodies, female mice either capable or incapable of producing antibodies were vaccinated and subsequently bred to males of the opposite genotype. Challenge infections of the genotypically identical F1 generation revealed the indispensability of maternal antibodies for vaccine-induced protection against cytomegaloviruses.

Hyperimmunplasma: Gewinnung, Verarbeitung und therapeutische Anwendungen

Das Prinzip der passiven Immunisierung ist seit dem 19. Jahrhundert bekannt und wird auch bei aktuellen Pandemien als Ansatz zur Prophylaxe und Therapie eingesetzt. Der Schutz wird hierbei übertragen durch Blut, Serum oder Plasma, welche Immunglobuline gegen spezifische Krankheitserreger, Bakterientoxine oder sonstige Antigene enthalten, sowie durch aus Humanplasma industriell aufgereinigte Immunglobuline. Die aktuell verwendeten Reinigungsverfahren für Immunglobuline aus Humanplasma beruhen auf der von Edwin J. Cohn entwickelten Fraktionierung von Plasma. Zur Gewinnung von Immunglobulinen mit hohen Antikörpertitern gegen spezifische Antigene, sogenannte Hyperimmunglobuline, muss zunächst Hyperimmunplasma gezielt von ausgewählten Spendern gewonnen werden. Diese Spender haben erhöhte Antikörpertiter gegen spezifische Krankheitserreger, Bakterientoxine oder sonstige Antigene, wenn sie im Rahmen einer vorangegangenen Infektion natürlich immunisiert wurden, einen zugelassenen Impfstoff zur Immunisierung erhalten haben oder gezielt zum Zweck der Plasmaspende immunisiert wurden. Aktuell sind in Deutschland, Österreich und der Schweiz Hyperimmunglobulinprodukte für verschiedene Anwendungen im Patienten zugelassen, von denen die meisten aus humanem Blutplasma gewonnen werden. Um die Herstellung der Produkte und damit letztlich die Behandlung der Patienten gewährleisten zu können, werden resiliente Lieferketten benötigt. Hierzu bedarf es unter anderem Änderungen in den Rahmenbedingungen für die Spenderimmunisierung in Deutschland.

Cytomegalovirus Anterior Uveitis: Clinical Manifestations, Diagnosis, Treatment, and Immunological Mechanisms

Little is known regarding anterior uveitis (AU), the most common ocular disease associated with cytomegalovirus (CMV) infection in immunocompetent populations. CMV AU is highly prevalent in Asia, with a higher incidence in men. Clinically, it manifests mainly as anterior chamber inflammation and elevated intraocular pressure (IOP). Acute CMV AU may resemble Posner-Schlossman syndrome with its recurrent hypertensive iritis, while chronic CMV AU may resemble Fuchs uveitis because of its elevated IOP. Without prompt treatment, it may progress to glaucoma; therefore, early diagnosis is critical to prognosis. Knowledge regarding clinical features and aqueous humor analyses can facilitate accurate diagnoses; so, we compared and summarized these aspects. Early antiviral treatment reduces the risk of a glaucoma surgery requirement, and therapeutic effects vary based on drug delivery. Both oral valganciclovir and topical ganciclovir can produce positive clinical outcomes, and higher concentration and frequency are beneficial in chronic CMV retinitis. An extended antiviral course could prevent relapses, but should be limited to 6 months to prevent drug resistance and side effects. In this review, we have systematically summarized the pathogenesis, clinical features, diagnostic and therapeutic aspects, and immunological mechanisms of CMV AU with the goal of providing a theoretical foundation for early clinical diagnosis and treatment.

A fully human neutralizing monoclonal antibody targeting a highly conserved epitope of the human cytomegalovirus glycoprotein B

Human cytomegalovirus causes severe diseases in children (by congenital infection) and immunocompromised patients. Treatment with antiviral agents, such as ganciclovir, is limited by their toxicity. In this study, we investigated the effectiveness of a fully human neutralizing monoclonal antibody to inhibit human cytomegalovirus infection and viral cell-to-cell spread. We isolated a potent neutralizing antibody, EV2038 (IgG1 lambda), targeting human cytomegalovirus glycoprotein B using Epstein-Barr virus transformation. This antibody inhibited human cytomegalovirus infection by all four laboratory strains and 42 Japanese clinical isolates, including ganciclovir-resistant isolates, with a 50% inhibitory concentration (IC50) ranging from 0.013 to 0.105 μg/mL, and 90% inhibitory concentration (IC90) ranging from 0.208 to 1.026 μg/mL, in both human embryonic lung fibroblasts (MRC-5) and human retinal pigment epithelial (ARPE-19) cells. Additionally, EV2038 prevented cell-to-cell spread of eight clinical viral isolates, with IC50 values ranging from 1.0 to 3.1 μg/mL, and IC90 values ranging from 13 to 19 μg/mL, in ARPE-19 cells. EV2038 recognized three discontinuous sequences on antigenic domain 1 of glycoprotein B (amino acids 549-560, 569-576, and 625-632), which were highly conserved among 71 clinical isolates from Japan and the United States. Pharmacokinetics study in cynomolgus monkeys suggested the potential efficacy of EV2038 in vivo, the concentration of which in serum remained higher than the IC90 values of cell-to-cell spread until 28 days after intravenous injection of 10 mg/kg EV2038. Our data strongly support EV2038 as a promising candidate and novel alternative for the treatment of human cytomegalovirus infection.

New data on efficacy of valacyclovir in secondary prevention of maternal-fetal transmission of cytomegalovirus

OBJECTIVE

Congenital cytomegalovirus (CMV) infection is the leading cause of non-genetic hearing and neurological deficits. The aim of our study was to evaluate the efficacy and safety of valacyclovir (VCV) treatment in preventing CMV transmission to the fetus after maternal primary infection.

METHODS

This was a retrospective, multicenter study evaluating the rate of maternal-fetal CMV transmission in pregnancies with maternal primary CMV infection treated with VCV at a dosage of 8 g per day (VCV group) compared with a control group of untreated women. Each case underwent virological testing to confirm maternal primary infection and to provide accurate dating of onset of infection. The primary outcome was the presence of congenital CMV infection at birth diagnosed based on polymerase chain reaction analysis of saliva, urine and/or blood samples. The efficacy of VCV treatment was assessed using logistic regression analysis adjusted for a propensity score.

RESULTS

In total, 143 patients were included in the final analysis, of whom 59 were in the VCV group and 84 were in the untreated control group. On propensity-score-adjusted analysis, VCV treatment was significantly associated with an overall reduction in the rate of maternal-fetal CMV transmission (odds ratio, 0.40 (95% CI, 0.18-0.90); P = 0.029). The rate of maternal-fetal CMV transmission, determined at birth, in the VCV vs control group was 7% (1/14) vs 10% (1/10) after periconceptional maternal primary infection (P = 1.00), 22% (8/36) vs 41% (19/46) after first-trimester maternal primary infection (P = 0.068) and 25% (2/8) vs 52% (14/27) after second-trimester maternal primary infection (P = 0.244). When analyzing the efficacy of VCV treatment according to maternal viremia at treatment initiation, there was a trend towards greater efficacy when patients were viremia-positive (21% vs 43%; P = 0.072) compared with when they were viremia-negative (22% vs 17%; P = 0.659). Maternal side effects associated with VCV were mild and non-specific in most cases.

CONCLUSION

Our findings indicate that VCV treatment of pregnant women with primary CMV infection reduces the risk of maternal-fetal transmission of CMV and may be effective in cases with primary infection in the first and second trimesters. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Characterization of Plasma Immunoglobulin G Responses in Elite Neutralizers of Human Cytomegalovirus

BACKGROUND

Human cytomegalovirus (HCMV) is the most common infectious complication of organ transplantation and cause of birth defects worldwide. There are limited therapeutic options and no licensed vaccine to prevent HCMV infection or disease. To inform development of HCMV antibody-based interventions, a previous study identified individuals with potent and broad plasma HCMV-neutralizing activity, termed elite neutralizers (ENs), from a cohort of HCMV-seropositive (SP) blood donors. However, the specificities and functions of plasma antibodies associated with EN status remained undefined.

METHODS

We sought to determine the plasma antibody specificities, breadth, and Fc-mediated antibody effector functions associated with the most potent HCMV-neutralizing responses in plasma from ENs (n = 25) relative to that from SP donors (n = 19). We measured antibody binding against various HCMV strains and glycoprotein targets and evaluated Fc-mediated effector functions, antibody-dependent cellular cytotoxicity (ADCC), and antibody-dependent cellular phagocytosis (ADCP).

RESULTS

We demonstrate that ENs have elevated immunoglobulin G binding responses against multiple viral glycoproteins, relative to SP donors. Our study also revealed potent HCMV-specific antibody-dependent cellular cytotoxicity and antibody-dependent cellular phagocytosis activity of plasma from ENs.

CONCLUSIONS

We conclude that antibody responses against multiple glycoprotein specificities may be needed to achieve potent plasma neutralization and that potently HCMV elite-neutralizing plasma antibodies can also mediate polyfunctional responses.

Lessons from Acquired Natural Immunity and Clinical Trials to Inform Next-Generation Human Cytomegalovirus Vaccine Development

Human cytomegalovirus (HCMV) infection, the most common cause of congenital disease globally, affecting an estimated 1 million newborns annually, can result in lifelong sequelae in infants, such as sensorineural hearing loss and brain damage. HCMV infection also leads to a significant disease burden in immunocompromised individuals. Hence, an effective HCMV vaccine is urgently needed to prevent infection and HCMV-associated diseases. Unfortunately, despite more than five decades of vaccine development, no successful HCMV vaccine is available. This review summarizes what we have learned from acquired natural immunity, including innate and adaptive immunity; the successes and failures of HCMV vaccine human clinical trials; the progress in related animal models; and the analysis of protective immune responses during natural infection and vaccination settings. Finally, we propose novel vaccine strategies that will harness the knowledge of protective immunity and employ new technology and vaccine concepts to inform next-generation HCMV vaccine development.

Maternal Fc-mediated non-neutralizing antibody responses correlate with protection against congenital human cytomegalovirus infection

Human cytomegalovirus (HCMV) is the most common congenital infection and a leading cause of stillbirth, neurodevelopmental impairment, and pediatric hearing loss worldwide. Development of a maternal vaccine or therapeutic to prevent congenital HCMV has been hindered by limited knowledge of the immune responses that protect against HCMV transmission in utero. To identify protective antibody responses, we measured HCMV-specific IgG binding and antiviral functions in paired maternal and cord blood sera from HCMV-seropositive transmitting (n = 41) and non-transmitting (n = 40) mother-infant dyads identified via a large, US-based, public cord blood bank. We found that high-avidity IgG binding to HCMV and antibody-dependent cellular phagocytosis (ADCP) were associated with reduced risk of congenital HCMV infection. We also determined that HCMV-specific IgG activation of FcγRI and FcγRII was enhanced in non-transmitting dyads and that increased ADCP responses were mediated through both FcγRI and FcγRIIA expressed on human monocytes. These findings suggest that engagement of FcγRI/FcγRIIA and Fc effector functions including ADCP may protect against congenital HCMV infection. Taken together, these data can guide future prospective studies on immune correlates against congenital HCMV transmission and inform HCMV vaccine and immunotherapeutic development.

Neutralizing Antibodies to Human Cytomegalovirus Recombinant Proteins Reduce Infection in an Ex Vivo Model of Developing Human Placentas

Human cytomegalovirus (HCMV) is the leading viral cause of congenital disease and permanent birth defects worldwide. Although the development of an effective vaccine is a public health priority, no vaccines are approved. Among the major antigenic targets are glycoproteins in the virion envelope, including gB, which facilitates cellular entry, and the pentameric complex (gH/gL/pUL128-131), required for the infection of specialized cell types. In this study, sera from rabbits immunized with the recombinant pentameric complex were tested for their ability to neutralize infection of epithelial cells, fibroblasts, and primary placental cell types. Sera from rhesus macaques immunized with recombinant gB or gB plus pentameric complex were tested for HCMV neutralizing activity on both cultured cells and cell column cytotrophoblasts in first-trimester chorionic villus explants. Sera from rabbits immunized with the pentameric complex potently blocked infection by pathogenic viral strains in amniotic epithelial cells and cytotrophoblasts but were less effective in fibroblasts and trophoblast progenitor cells. Sera from rhesus macaques immunized with the pentameric complex and gB more strongly reduced infection in fibroblasts, epithelial cells, and chorionic villus explants than sera from immunization with gB alone. These results suggest that the pentameric complex and gB together elicit antibodies that could have potential as prophylactic vaccine antigens.

Amniocentesis to diagnose congenital cytomegalovirus infection following maternal primary infection

BACKGROUND

Congenital cytomegalovirus infection following maternal primary cytomegalovirus infection affects approximately 0.4% of newborns in the United States but may be hard to diagnose prenatally.

OBJECTIVE

To evaluate the current sensitivity and specificity of amniocentesis in detecting congenital cytomegalovirus infection.

STUDY DESIGN

Secondary analysis of a multicenter randomized placebo-controlled trial designed to evaluate whether cytomegalovirus hyperimmune globulin reduces congenital cytomegalovirus infection in neonates of individuals diagnosed with primary cytomegalovirus infection before 24 weeks of gestation. At randomization, subjects had no clinical evidence of fetal infection. Eligible subjects were randomized to monthly infusions of cytomegalovirus hyperimmune globulin or placebo until delivery. Although not required by the trial protocol, amniocentesis following randomization was permitted. The fetuses and neonates were tested for the presence of cytomegalovirus at delivery. Comparisons were made between those with and without amniocentesis and between those with cytomegalovirus-positive and negative results, using chi-square or Fisher exact test for categorical variables and the Wilcoxon rank sum test or t test for continuous variables. A P value of <.05 was considered significant.

RESULTS

From 2012 to 2018, 397 subjects were included, of whom 55 (14%) underwent amniocentesis. Cytomegalovirus results were available for 53 fetuses and neonates. Fourteen amniocenteses were positive (25%). Gestational age at amniocentesis was similar between those with and without cytomegalovirus present, as was the interval between maternal diagnosis and amniocentesis. The prevalence of fetal or neonatal infection was 26% (14/53). The neonates of all 12 subjects with a positive amniocentesis and available results had cytomegalovirus infection confirmed at delivery, as did 2 neonates from the group of 41 subjects with a negative amniocentesis, with a sensitivity of 86% (95% confidence interval, 57-98), specificity of 100% (95% confidence interval, 91-100), positive predictive value of 100% (95% confidence interval, 74-100), and negative predictive value of 95% (95% confidence interval, 83-99). Amniocentesis-positive pregnancies were delivered at an earlier gestational age (37.4 vs 39.6 weeks; P<.001) and had lower birthweights (2583±749 vs 3428±608 g, P=.004) than amniocentesis-negative pregnancies.

CONCLUSION

Amniocentesis results are an accurate predictor of congenital cytomegalovirus infection.

Universal First-Trimester Cytomegalovirus Screening and Valaciclovir Prophylaxis in Pregnant Persons: A Cost-Effectiveness Analysis

BACKGROUND

Recent studies suggest a possible benefit of valaciclovir prophylaxis to prevent vertical transmission after a positive serologic screen for primary maternal cytomegalovirus infection during pregnancy, although its cost-effectiveness remains uncertain.

OBJECTIVE

We sought to determine the circumstances under which universal first-trimester maternal serologic screening for maternal cytomegalovirus infection, with valaciclovir prophylaxis to prevent congenital cytomegalovirus, is cost-effective.

STUDY DESIGN

We performed a decision analysis from the perspective of the pregnant person to assess whether universal maternal screening in the first trimester, with subsequent valaciclovir prophylaxis (8g/day from time of positive serologic screen for primary maternal cytomegalovirus infection through 21 weeks' gestation) for those who are acutely infected, is cost-effective compared to usual care (i.e., no routine serologic screening, but amniocentesis if mid-trimester sonographic findings suggest cytomegalovirus). For baseline estimates, we assumed a 35% risk of congenital cytomegalovirus after primary maternal infection and a 71% risk reduction with valaciclovir. We varied valaciclovir's efficacy to identify whether and at what threshold universal screening would be estimated to be cost-effective, compared to usual care. Monte Carlo analyses were performed. A willingness-to-pay threshold of $100,000/quality-adjusted life year was used to define cost-effectiveness.

RESULTS

Under base-case estimates, first-trimester universal screening and valaciclovir prophylaxis for seropositive pregnant persons with acute cytomegalovirus infection is not cost-effective, with a cost of $137,854 per maternal QALY, but results in 14 fewer cytomegalovirus-affected children per 100,000 pregnancies compared to usual care. In one-way sensitivity analysis, universal screening and treatment is estimated to be the cost-effective strategy if the incidence of primary maternal cytomegalovirus infection exceeds 2.6%, baseline risk of vertical transmission of cytomegalovirus without prophylaxis is greater than 36.8%, and the risk reduction of vertical transmission of cytomegalovirus with valaciclovir prophylaxis exceeds 75.9%. In Monte Carlo analyses, first-trimester universal serologic screening with valaciclovir prophylaxis is estimated to be the cost-effective strategy in 46.8% of runs.

CONCLUSION

Universal first-trimester serologic screening with valaciclovir prophylaxis is not the cost-effective strategy for antenatal management of cytomegalovirus under the base-case estimates. Although universal screening is cost-effective in certain circumstances when the efficacy of valaciclovir exceeds the base case, that result is not robust to variation of estimates across their reasonable ranges. These data can inform future studies to evaluate screening and treatment to prevent congenital CMV.

Audiovestibular Consequences of Congenital Cytomegalovirus Infection: Greater Vulnerability of the Vestibular Part of the Inner Ear

OBJECTIVES

To investigate the impact of congenital cytomegalovirus infection on cochlear and vestibular function.

DESIGN

This retrospective study conducted between March 2014 and March 2020 included children with confirmed congenital cytomegalovirus infection who underwent a complete audio-vestibular evaluation. It included a bithermal caloric test, a video head impulse test and a cervical vestibular evoked myogenic potential associated with a complete hearing assessment.

RESULTS

The cohort of 130 children included in the study had a median age of 21 months (interquartile range: 12 to 37 months). Eighty-three children (64%) showed an inner ear impairment (both cochlear and vestibular). The vestibular part of the inner ear was significantly more frequently impaired than the cochlear part (ρ = 0.003). Sixty-two children (48%) showed confirmed hearing impairment. The severity of hearing loss was variable, with a high proportion of profound hearing loss (30/62, 48%), which was often bilateral (47/62, 76%). The vestibular assessment showed a canal function disorder in 67 children (88%) and an otolith function disorder in 63 children (83%; ρ = 0.36). The video head impulse test was significantly less altered (64%) compared with the bithermal caloric test (80%; ρ = 0.02) and the cervical vestibular evoked myogenic potential (83%; ρ = 0.009). Only seven out of 83 children (8%) showed hearing loss without vestibular dysfunction, of which only one had a normal hearing screening test at birth. For the children who passed the hearing screening test at birth and presented an inner ear impairment [n = 36, median age: 16 (11 to 34) months], vestibular disorders were later found in 35 children (97%) and 17 of them (47%) developed hearing loss secondarily. This underlines the importance of assessing both vestibular and auditory parts of the inner ear. When comparing the agreement of cochlear and vestibular impairment, the severity and the laterality of the impairment were low [Cohen's kappa 0.31 (0.22 to 0.40) and 0.43 (0.32 to 0.55), respectively].

CONCLUSION

In our study, we demonstrated that although both cochlear and vestibular parts of the inner ear can be impaired by congenital cytomegalovirus infection, the vestibular part seems more often impaired compared with the cochlear part. This underlines the importance of vestibular evaluation in the follow-up of cytomegalovirus-infected children associated with hearing assessment.

Development of broadly neutralizing antibodies targeting the cytomegalovirus subdominant antigen gH

Human cytomegalovirus (HCMV) is a β-herpesvirus that increases morbidity and mortality in immunocompromised individuals including transplant recipients and newborns. New anti-HCMV therapies are an urgent medical need for diverse patient populations. HCMV infection of a broad range of host tissues is dependent on the gH/gL/gO trimer and gH/gL/UL28/UL130/UL131A pentamer complexes on the viral envelope. We sought to develop safe and effective therapeutics against HCMV by generating broadly-neutralizing, human monoclonal antibodies (mAbs) from VelocImmune® mice immunized with gH/gL cDNA. Following high-throughput binding and neutralization screening assays, 11 neutralizing antibodies were identified with unique CDR3 regions and a high-affinity (KD 1.4-65 nM) to the pentamer complex. The antibodies bound to distinct regions within Domains 1 and 2 of gH and effectively neutralized diverse clinical strains in physiologically relevant cell types including epithelial cells, trophoblasts, and monocytes. Importantly, combined adminstration of mAbs with ganciclovir, an FDA approved antiviral, greatly limited virus dissemination. Our work identifies several anti-gH/gL mAbs and sheds light on gH neutralizing epitopes that can guide future vaccine strategies.

Describing the impact of maternal hyperimmune globulin and valaciclovir on the outcomes of CMV infection in pregnancy: a systematic review

Cytomegalovirus is the leading infectious cause of congenital neurological disabilities. Valaciclovir and CMV hyperimmune globulin may reduce vertical transmission and sequelae in neonates. A systematic review on valaciclovir and CMV hyperimmune globulin in preventing vertical transmission or reducing sequelae in neonates was conducted to 3 September 2021. Valaciclovir as a preventative strategy was supported by a well-conducted randomised controlled trial. Evidence supporting valaciclovir as a treatment strategy was limited to observational studies at moderate risk of bias. CMV hyperimmune globulin was not supported as a preventative strategy in two RCTs, which contrasted with observational studies. Evidence favouring CMV hyperimmune globulin as a treatment strategy was limited to observational studies at moderate risk of bias. The role of valaciclovir and CMV hyperimmune globulin in CMV infection in pregnancy is still being defined. Valaciclovir to prevent vertical transmission has the highest quality evidence in favour of use.

Congenital Human Cytomegalovirus Infection Is Associated With Decreased Transplacental IgG Transfer Efficiency Due to Maternal Hypergammaglobulinemia

BACKGROUND

Placentally transferred maternal immunoglobulin G (IgG) protects against pathogens in early life, yet vertically transmitted infections can interfere with transplacental IgG transfer. Although human cytomegalovirus (HCMV) is the most common placentally-transmitted viral infection worldwide, the impact of congenital HCMV (cCMV) infection on transplacental IgG transfer has been underexplored.

METHODS

We evaluated total and antigen-specific maternal and cord blood IgG levels and transplacental IgG transfer efficiency in a US-based cohort of 93 mother-infant pairs including 27 cCMV-infected and 66 cCMV-uninfected pairs, of which 29 infants were born to HCMV-seropositive nontransmitting mothers and 37 to HCMV-seronegative mothers. Controls were matched on sex, race/ethnicity, maternal age, and delivery year.

RESULTS

Transplacental IgG transfer efficiency was decreased by 23% (95% confidence interval [CI] 10-36%, P = .0079) in cCMV-infected pairs and 75% of this effect (95% CI 28-174%, P = .0085) was mediated by elevated maternal IgG levels (ie, hypergammaglobulinemia) in HCMV-transmitting women. Despite reduced transfer efficiency, IgG levels were similar in cord blood from infants with and without cCMV infection.

CONCLUSIONS

Our results indicate that cCMV infection moderately reduces transplacental IgG transfer efficiency due to maternal hypergammaglobulinemia; however, infants with and without cCMV infection had similar antigen-specific IgG levels, suggesting comparable protection from maternal IgG acquired via transplacental transfer.

Potential of Anti-CMV Immunoglobulin Cytotect CP® In Vitro and Ex Vivo in a First-Trimester Placenta Model

Background: Congenital CMV infection is the leading cause of neonatal neurological deficit. We herein studied in vitro and ex vivo the potential of the hyperimmune globulin Cytotect CP^® (Biotest, Germany) for congenital infection prevention and treatment. Methods: In vitro neutralization assays were conducted in fibroblasts and retinal epithelial cells on the CMV strains TB40/E and VHL/E to determine the 50% and 90% neutralizing doses (ND50 and ND90). The toxicity was assessed by measuring LDH release. Ex vivo assays were conducted in first-trimester villi explants with the TB40/E strain, namely, neutralization assays, the prevention of villi infection, and the inhibition of viral replication in infected villi. Viability was assessed by β-HCG quantification in supernatants. Results: The in vitro neutralization tests showed that Cytotect CP^®® inhibits the development of infection foci (DN50: 0.011–0.014 U/mL for VHL/E and 0.032–0.033 U/mL for TB40E) without any toxicity. In the ex vivo neutralization assays, the DN50 were 0.011 U/mL on day 7 and 0.093 U/mL on day 14. For the prevention of villi infection, the EC50 was 0.024 U/mL on day 7. Cytotect-CP^® did not inhibit viral growth in infected villi. No impact on villi viability was observed. Conclusions: These results sustained that Cytotect CP^® has the potential to prevent CMV congenital infection.

Dominant Antiviral CD8+ T Cell Responses Empower Prophylactic Antibody-Eliciting Vaccines Against Cytomegalovirus

Human cytomegalovirus (HCMV) is an ubiquitous herpesvirus that can cause serious morbidity and mortality in immunocompromised or immune-immature individuals. A vaccine that induces immunity to CMV in these target populations is therefore highly needed. Previous attempts to generate efficacious CMV vaccines primarily focused on the induction of humoral immunity by eliciting neutralizing antibodies. Current insights encourage that a protective immune response to HCMV might benefit from the induction of virus-specific T cells. Whether addition of antiviral T cell responses enhances the protection by antibody-eliciting vaccines is however unclear. Here, we assessed this query in mouse CMV (MCMV) infection models by developing synthetic vaccines with humoral immunity potential, and deliberately adding antiviral CD8⁺ T cells. To induce antibodies against MCMV, we developed a DNA vaccine encoding either full-length, membrane bound glycoprotein B (gB) or a secreted variant lacking the transmembrane and intracellular domain (secreted (s)gB). Intradermal immunization with an increasing dose schedule of sgB and booster immunization provided robust viral-specific IgG responses and viral control. Combined vaccination of the sgB DNA vaccine with synthetic long peptides (SLP)-vaccines encoding MHC class I-restricted CMV epitopes, which elicit exclusively CD8⁺ T cell responses, significantly enhanced antiviral immunity. Thus, the combination of antibody and CD8⁺ T cell-eliciting vaccines provides a collaborative improvement of humoral and cellular immunity enabling enhanced protection against CMV.

Neutralizing Antibodies Limit Cell-Associated Spread of Human Cytomegalovirus in Epithelial Cells and Fibroblasts

Human cytomegalovirus (HCMV) can cause severe clinical disease in immunocompromised individuals, such as allograft recipients and infants infected in utero. Neutralizing activity of antibodies, measured as the ability to prevent the entry of cell-free virus, has been correlated with the reduction in HCMV transmission and the severity of HCMV-associated disease. However, in vivo HCMV amplification may occur mainly via cell-to-cell spread. Thus, quantifying the inhibition of cell-to-cell transmission could be important in the evaluation of therapeutic antibodies and/or humoral responses to infection or immunization. Here, we established a quantitative plaque reduction assay, which allowed for the measurement of the capacity of antibodies to limit HCMV spread in vitro. Using an automated fluorescence spot reader, infection progression was assayed by the expansion of viral plaques during the course of infection with various GFP-expressing viruses. We found that in contrast to non-neutralizing monoclonal antibodies (mAbs), neutralizing mAbs against both glycoprotein B and H (gB and gH) could significantly inhibit viral plaque expansion of different HCMV strains and was equally efficient in fibroblasts as in epithelial cells. In contrast, an anti-pentamer mAb was active only in epithelial cells. Taken together, our data demonstrate that specific anti-HCMV mAbs can significantly limit cell-associated virus spread in vitro.

The Current Challenges in Developing Biological and Clinical Predictors of Congenital Cytomegalovirus Infection

Congenital cytomegalovirus (CMV) infection may cause severe long-term sequelae. Recent studies have demonstrated that early antiviral therapy for infants with symptomatic congenital CMV (cCMV) infection may improve neurological outcomes; thus, accurate identification of newborns at high risk of cCMV infection may contribute to improved outcomes in affected children. However, maternal serological screening for cCMV infection by diagnosing primary infection during pregnancy, which is a popular screening strategy, is inefficient, because the number of cCMV infections with nonprimary causes, including reactivation of or reinfection with CMV, is larger than that of cCMV infections with primary causes. Low levels of neutralizing antibodies against pentameric complex and potent CMV-specific T cell-mediated immune responses are associated with an increased risk of cCMV infection. Conversely, our prospective cohort studies revealed that the presence of maternal fever/flu-like symptoms, threatened miscarriage/premature delivery, or actual premature delivery are risk factors for cCMV infection among both women with normal pregnancies and those with high-risk ones, regardless of whether the infection is primary or nonprimary. This review focused on host immune responses to human CMV and current knowledge of potential biological and clinical factors that are predictive of cCMV infection.

Current practices of management of maternal and congenital Cytomegalovirus infection during pregnancy after a maternal primary infection occurring in first trimester of pregnancy: Systematic review

INTRODUCTION

Congenital CMV infection is the first worldwide cause of congenital viral infection but systematic screening of pregnant women and newborns for CMV is still debated in many countries.

OBJECTIVES

This systematic review aims to provide the state of the art on current practices concerning management of maternal and congenital CMV infection during pregnancy, after maternal primary infection (PI) in first trimester of pregnancy.

DATA SOURCES

Electronically searches on databases and hand searches in grey literature.

STUDY ELIGIBILITY CRITERIA AND PARTICIPANTS

Primary outcome was listing biological, imaging, and therapeutic management interventions in two distinct populations: population 1 are pregnant women with PI, before or without amniocentesis; population 2 are pregnant women with congenitally infected fetuses (after positive amniocentesis). Secondary outcome was pregnancy outcome in population 2.

RESULTS

Out of 4,134 studies identified, a total of 31 studies were analyzed, with 3,325 pregnant women in population 1 and 1,021 pregnant women in population 2, from 7 countries (Belgium, France, Germany, Israel, Italy, Spain and USA). In population 1, ultrasound (US) examination frequency was 0.75/month, amniocentesis in 82% cases, maternal viremia in 14% and preventive treatment with hyperimmune globulins (HIG) or valaciclovir in respectively 14% and 4% women. In population 2, US examination frequency was 1.5/month, magnetic resonance imaging (MRI) in 44% cases at 32 weeks gestation (WG), fetal blood sampling (FBS) in 24% at 28 WG, and curative treatment with HIG or valaciclovir in respectively 9% and 8% patients.

CONCLUSIONS

This systematic review illustrates management of maternal and congenital CMV during pregnancy in published and non-published literature, in absence of international consensus.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019124342.

Leaning towards Cytomegalovirus serological screening in pregnancy to prevent congenital infection: a cost-effectiveness perspective

OBJECTIVE

To assess the cost-effectiveness of prenatal detection of congenital cytomegalovirus (cCMV) following maternal primary infection in the first trimester within standard pregnancy follow-up or involving population-based screening (serological testing at 7 and 12 weeks of gestation), with or without secondary prevention (valaciclovir) in maternal CMV primary infection.

DESIGN

Cost-effectiveness study from the perspective of the French national health insurance system.

SETTING

Cost-effectiveness based on previously published probability estimates and associated plausible ranges hypothetical population of 1,000,000 pregnant women.

POPULATION

Hypothetical population of 1,000,000 pregnant women.

METHODS

Cost-effectiveness of detecting fetal cCMV in terms of the total direct medical costs involved and associated expected outcomes.

MAIN OUTCOME MEASURES

Detection rates and clinical outcomes at birth.

RESULTS

Moving to a population-based approach for targeting fetal CMV infections would generate high monetary and organizational costs while increasing detection rates from 15% to 94%. This resource allocation would help implementing horizontal equity according to which individuals with similar medical needs should be treated equally. Secondary prevention with valaciclovir had a significant effect on maternal-fetal CMV transmission and clinical outcomes in newborns, with a 58% decrease of severely infected newborns for a 3.5% additional total costs. Accounting for women decision-making (amniocentesis uptake and termination of pregnancy in severe cases) did not impact the cost-effectiveness results.

CONCLUSIONS

These findings could fuel thinking on the opportunity of developing clinical guidelines to rule identification of cCMV infection and administration of in-utero treatment. These findings could fuel the development of clinical guidelines on the identification of congenital CMV infection and the administration of treatment in utero.

TWEETABLE ABSTRACT

CMV serological screening followed by valaciclovir prevention may prevent 58% to 71% of severe cCMV cases for 38 € per pregnancy.

Less common bacterial, fungal and viral infections: review of management in the pregnant patient

This review is a comprehensive summary of treatment options for pregnant patients with less common bacterial, fungal, and viral infections. It offers guidance to clinicians based on the most recently published evidence-based research and expert recommendations. A search of MEDLINE (inception to March 2021) and the CDC website was performed. Liposomal amphotericin B is the preferred therapy for cryptococcosis, histoplasmosis, oesophageal candidiasis, and coccidioidomycosis, especially during the first trimester due to teratogenic concerns with azole antifungals. For oral candidiasis, clotrimazole troches or miconazole mucoadhesive buccal tablets are recommended. A β-lactam antimicrobial is preferred over doxycycline for various manifestations of Lyme disease and the drug of choice for Pneumocystis pneumonia is trimethoprim/sulfamethoxazole. Acyclovir is the preferred antiviral for varicella zoster virus. Fluoroquinolones, macrolides, and aminoglycosides should be avoided if possible and there are alternate agents available for an effective treatment regimen. There is a scarcity of clinical data in pregnant patients with less common bacterial, fungal and viral infections. This population lacks definitive recommendations in many clinical practice guidelines. The key to optimizing therapy is a comprehensive review of the available evidence and a careful balance of risks and benefits before final treatment decisions.

Serial Monitoring and Hyperimmunoglobulin versus Standard of Care to Prevent Congenital Cytomegalovirus Infection: A Phase III Randomized Trial

INTRODUCTION

Nonrandomized studies support the potential of cytomegalovirus hyperimmunoglobulin (CMV-HyperIg) in preventing maternofetal CMV transmission, but prospective interventional studies show equivocal results. We pre-sent a prospective phase-III international randomized open-label trial on the potential effect of CMV-HyperIg following serial monitoring of CMV serostatus.

METHODS

CMV-seronegative pregnant women (gestational age [GA] <14 weeks) were 1:1 randomized to monthly CMV-serostatus monitoring and CMV-HyperIg upon seroconversion (treatment), or routine prenatal care with CMV-serostatus testing at end of pregnancy (control). Ethical considerations required that control subjects with confirmed seroconversion be offered Cytotect®. The primary endpoint was the proportion of fetuses/newborns with congenital CMV infection. Secondary endpoints included neonatal CMV disease and safety during the 24-month follow-up.

RESULTS

The treatment arm counted 4,800 randomized subjects: 52 seroconverted (median GA 24 [11-35] weeks), of which 45 completed follow-up. The control arm counted 4,735 randomized subjects: 42 seroconverted, of which 34 completed follow-up (evaluable data for 28 newborns) and 8 subjects chose off-label Cytotect®. Congenital CMV rates were 13/28 newborns (46.4% [CI 27.51; 66.13]) vs. 16/45 newborns (35.6% [CI 21.87; 51.22]) in control and treated arms, respectively (p = 0.46). Newborn CMV disease was mostly mild and spontaneously resolving. There were no major safety concerns. The target sample was not reached within an acceptable time frame.

CONCLUSIONS

Serial monitoring of CMV serostatus with CMV-HyperIg treatment was associated with a mild nonsignificant reduction in the vertical CMV transmission rate. Studies on the optimal preventive strategy are hampered by epidemiological and ethical challenges and should focus on GA-dependent transmission rates and accurate dating of infection.

Safety and Immunogenicity of an Anti-Zika Virus DNA Vaccine

BACKGROUND

Although Zika virus (ZIKV) infection is typically self-limiting, other associated complications such as congenital birth defects and the Guillain-Barré syndrome are well described. There are no approved vaccines against ZIKV infection.

METHODS

In this phase 1, open-label clinical trial, we evaluated the safety and immunogenicity of a synthetic, consensus DNA vaccine (GLS-5700) encoding the ZIKV premembrane and envelope proteins in two groups of 20 participants each. The participants received either 1 mg or 2 mg of vaccine intradermally, with each injection followed by electroporation (the use of a pulsed electric field to introduce the DNA sequence into cells) at baseline, 4 weeks, and 12 weeks.

RESULTS

The median age of the participants was 38 years, and 60% were women; 78% were White and 22% Black; in addition, 30% were Hispanic. At the interim analysis at 14 weeks (i.e., after the third dose of vaccine), no serious adverse events were reported. Local reactions at the vaccination site (e.g., injection-site pain, redness, swelling, and itching) occurred in approximately 50% of the participants. After the third dose of vaccine, binding antibodies (as measured on enzyme-linked immunosorbent assay) were detected in all the participants, with geometric mean titers of 1642 and 2871 in recipients of 1 mg and 2 mg of vaccine, respectively. Neutralizing antibodies developed in 62% of the samples on Vero-cell assay. On neuronal-cell assay, there was 90% inhibition of ZIKV infection in 70% of the serum samples and 50% inhibition in 95% of the samples. The intraperitoneal injection of postvaccination serum protected 103 of 112 IFNAR knockout mice (bred with deletion of genes encoding interferon-α and interferon-β receptors) (92%) that were challenged with a lethal dose of ZIKV-PR209 strain; none of the mice receiving baseline serum survived the challenge. Survival was independent of the neutralization titer.

CONCLUSIONS

In this phase 1, open-label clinical trial, a DNA vaccine elicited anti-ZIKV immune responses. Further studies are needed to better evaluate the safety and efficacy of the vaccine. (Funded by GeneOne Life Science and others; ZIKA-001 ClinicalTrials.gov number, NCT02809443.).

Congenital Cytomegalovirus Infection: Epidemiology, Timely Diagnosis, and Management

Congenital cytomegalovirus (cCMV) infection is common because of the ubiquitous nature of the virus and the lack of an effective prevention strategy during pregnancy. Most infants with cCMV are asymptomatic, although a notable subset can have sequelae including, most commonly, sensorineural hearing loss and neurodevelopmental disability, which may not be present at birth. Timely screening for cytomegalovirus in the first weeks after birth is critical to appropriately diagnose congenital infection, evaluate affected infants, and determine the treatment course. Antiviral therapy with valganciclovir can optimize end hearing and neurodevelopmental outcomes in symptomatic infants. This review discusses the epidemiology and clinical manifestations of cCMV, targeted and universal screening approaches, and treatment and monitoring of infants with cCMV.

Congenital cytomegalovirus (CMV) for the pediatric otolaryngologist

Cytomegalovirus (CMV) is a double-stranded DNA virus and a member of the herpesvirus family. It is the most common congenital viral infection. For symptomatic infections, symptoms can vary widely but tends to have a predilection for the central nervous system and for the reticuloendothelial system. Sensorineural hearing loss (SNHL) is by far the most common sequelae of congenital CMV infection. For this reason, it is imperative to understand the screening, diagnosis, and possible treatment options for congenital CMV induced SNHL. This literature review explores the association of CMV with hearing loss, screening for congenital CMV infections, possible treatments options, and the development of a possible vaccine.

A Novel Strain-Specific Neutralizing Epitope on Glycoprotein H of Human Cytomegalovirus

Human cytomegalovirus (HCMV) is a ubiquitous pathogen that causes severe clinical disease in immunosuppressed patients and congenitally infected newborn infants. Viral envelope glycoproteins represent attractive targets for vaccination or passive immunotherapy. To extend the knowledge of mechanisms of virus neutralization, monoclonal antibodies (MAbs) were generated following immunization of mice with HCMV virions. Hybridoma supernatants were screened for in vitro neutralization activity, yielding three potent MAbs, 6E3, 3C11, and 2B10. MAbs 6E3 and 3C11 blocked infection of all viral strains that were tested, while MAb 2B10 neutralized only 50% of the HCMV strains analyzed. Characterization of the MAbs using indirect immunofluorescence analyses demonstrated their reactivity with recombinantly derived gH. While MAbs 6E3 and 3C11 reacted with gH when expressed alone, 2B10 detected gH only when it was coexpressed with gB and gL. Recognition of gH by 3C11 was dependent on the expression of the entire ectodomain of gH, whereas 6E3 required residues 1 to 629 of gH. The strain-specific determinant for neutralization by Mab 2B10 was identified as a single Met→Ile amino acid polymorphism within gH, located within the central part of the protein. The polymorphism is evenly distributed among described HCMV strains. The 2B10 epitope thus represents a novel strain-specific antibody target site on gH of HCMV. The dependence of the reactivity of 2B10 on the simultaneous presence of gB/gH/gL will be of value in the structural definition of this tripartite complex. The 2B10 epitope may also represent a valuable tool for diagnostics to monitor infections/reinfections with different HCMV strains during pregnancy or after transplantation. IMPORTANCE HCMV infections are life threatening to people with compromised or immature immune systems. Understanding the antiviral antibody repertoire induced during HCMV infection is a necessary prerequisite to define protective antibody responses. Here, we report three novel anti-gH MAbs that potently neutralized HCMV infectivity. One of these MAbs (2B10) targets a novel strain-specific conformational epitope on gH that only becomes accessible upon coexpression of the minimal fusion machinery gB/gH/gL. Strain specificity is dependent on a single amino acid polymorphism within gH. Our data highlight the importance of strain-specific neutralizing antibody responses against HCMV. The 2B10 epitope may also represent a valuable tool for diagnostics to monitor infections/reinfections with different HCMV strains during pregnancy or after transplantation. In addition, the dependence of the reactivity of 2B10 on the simultaneous presence of gB/gH/gL will be of value in the structural definition of this tripartite complex.

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.

New evidence on prognostic features, prevention and treatment of congenital Cytomegalovirus infection

PURPOSE OF REVIEW

Congenital Cytomegalovirus (CMV) infection remains a major cause of lifelong disability, with no systematic screening implemented in pregnancy or the postnatal period. In this review article, we outline the preventive strategies, antenatal prognostic features and experimental therapies as well as evidence of efficacy from recent trials.

RECENT FINDINGS

A recent randomized, double blinded, placebo-controlled study investigated the efficacy of Valaciclovir in women contracting primary CMV in the periconception period or first trimester. They concluded that Valaciclovir at a dose of 8 g/day is effective in reducing the rate of foetal CMV infection following early maternal primary infection. Administration of CMV hyperimmune globulin (HIG) was investigated in a recent randomized double-masked controlled trial. This study concluded that CMV HIG was ineffective at reducing the risk of congenital CMV among women with primary CMV in early pregnancy.

SUMMARY

Congenital CMV infection remains a significant cause of disability. There is currently no vaccine available, with the best preventive strategy being patient education on transmission as well as hygiene measures to reduce risk of exposure. Experimental therapies have been investigated in recent years and there is evidence supporting the use of Valaciclovir. Data for the efficacy of CMV HIG remains inconsistent and administration is currently limited to clinical trial settings.