Prevention of maternal-fetal transmission of cytomegalovirus after primary maternal infection in the first trimester by biweekly hyperimmunoglobulin administration

Consensus recommendation for prenatal, neonatal and postnatal management of congenital cytomegalovirus infection from the European congenital infection initiative (ECCI)

Congenital cytomegalovirus (cCMV) infection carries a significant burden with a 0.64% global prevalence and a 17-20% chance of serious long-term effects in children. Since the last guidelines, our understanding, particularly regarding primary maternal infections, has improved. A cCMV guidelines group was convened under the patronage of the European Society of Clinical Virology in April 2023 to refine these insights. The quality and validity of selected studies were assessed for potential biases and the GRADE framework was employed to evaluate quality of evidence across key domains. The resulting recommendations address managing cCMV, spanning prevention to postnatal care. Emphasizing early and accurate maternal diagnosis through serological tests enhances risk management and prevention strategies, including using valaciclovir to prevent vertical transmission. The guidelines also strive to refine personalized postnatal care based on risk assessments, ensuring targeted interventions for affected families.

Evaluation of an automated real-time transcription-mediated amplification (TMA) assay for detection and quantification of cytomegalovirus DNA in different clinical specimens

BACKGROUND

Reliable and fast detection and quantification of human cytomegalovirus (CMV) DNA in various diagnostic specimens is essential for care of immunocompromised or congenitally infected individuals.

OBJECTIVES

To evaluate the analytical and clinical performance of the Panther Aptima® CMV (Hologic) quantitative real-time transcription mediated amplification (TMA) assay.

STUDY DESIGN

Performance of the TMA assay run on the Hologic Panther Fusion was analysed for 32 proficiency testing samples and 21 quantitative reproducibility panel samples; additionally, we compared results of TMA assay and routine quantitative real-time PCR assays ("PCR-A"= Biomérieux CMV R-gene® or "PCR-B"= Laboratory-developed CMV-PCR) in 518 diagnostic specimens (254 plasma, 120 EDTA whole blood, 43 urine, 45 amniotic fluid and 56 breast milk) at two university hospital laboratories.

RESULTS

All proficiency panel samples were correctly identified and quantified by the TMA assay; replicate testing of the reproducibility panel samples showed good reproducibility within and between the two laboratories. Sensitivity in plasma and WB was higher for the TMA assay detecting low-level CMV-DNAemia in samples tested negative by routine PCR. Quantitative CMV-DNAemia values correlated well between TMA and real-time PCR. Similarly, urine, AF and BM specimens showed a high rate of concordant results (91%, 98% and 98%, respectively) among TMA and PCR with good correlation of quantitative values.

CONCLUSION

The performance of the Aptima® CMV TMA assay for viral blood load testing compared well to established real-time PCRs. In addition, it can be useful for diagnostics in urine, amniotic fluid and breast milk specimens.

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.

Asymptomatic CMV infection at birth following maternal primary infection despite valacyclovir treatment and a subsequent negative amniocentesis. Case report

Valacyclovir is currently the only pharmacological intervention demonstrated to reduce the risk of vertical CMV congenital infection within a randomized clinical trial in case of primary infection during pregnancy. So far, no data are available on the prognosis of children with congenital CMV infection diagnosed at birth after a negative amniocentesis whose mother were treated with valacyclovir during pregnancy, therefore it is essential to carry out a rigorous neurocognitive follow-up in these children in order to investigate the potential clinical consequence.

Anti-CMV therapy, what next? A systematic review

Human cytomegalovirus (HCMV) is one of the main causes of serious complications in immunocompromised patients and after congenital infection. There are currently drugs available to treat HCMV infection, targeting viral polymerase, whose use is complicated by toxicity and the emergence of resistance. Maribavir and letermovir are the latest antivirals to have been developed with other targets. The approval of letermovir represents an important innovation for CMV prevention in hematopoietic stem cell transplant recipients, whereas maribavir allowed improving the management of refractory or resistant infections in transplant recipients. However, in case of multidrug resistance or for the prevention and treatment of congenital CMV infection, finding new antivirals or molecules able to inhibit CMV replication with the lowest toxicity remains a critical need. This review presents a range of molecules known to be effective against HCMV. Molecules with a direct action against HCMV include brincidofovir, cyclopropavir and anti-terminase benzimidazole analogs. Artemisinin derivatives, quercetin and baicalein, and anti-cyclooxygenase-2 are derived from natural molecules and are generally used for different indications. Although they have demonstrated indirect anti-CMV activity, few clinical studies were performed with these compounds. Immunomodulating molecules such as leflunomide and everolimus have also demonstrated indirect antiviral activity against HCMV and could be an interesting complement to antiviral therapy. The efficacy of anti-CMV immunoglobulins are discussed in CMV congenital infection and in association with direct antiviral therapy in heart transplanted patients. All molecules are described, with their mode of action against HCMV, preclinical tests, clinical studies and possible resistance. All these molecules have shown anti-HCMV potential as monotherapy or in combination with others. These new approaches could be interesting to validate in clinical trials.

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.

Relationship of maternal cytomegalovirus-specific antibody responses and viral load to vertical transmission risk following primary maternal infection in a rhesus macaque model

Cytomegalovirus (CMV) is the most common congenital infection and cause of birth defects worldwide. Primary CMV infection during pregnancy leads to a higher frequency of congenital CMV (cCMV) than maternal re-infection, suggesting that maternal immunity confers partial protection. However, poorly understood immune correlates of protection against placental transmission contributes to the current lack of an approved vaccine to prevent cCMV. In this study, we characterized the kinetics of maternal plasma rhesus CMV (RhCMV) viral load (VL) and RhCMV-specific antibody binding and functional responses in a group of 12 immunocompetent dams with acute, primary RhCMV infection. We defined cCMV transmission as RhCMV detection in amniotic fluid (AF) by qPCR. We then leveraged a large group of past and current primary RhCMV infection studies in late-first/early-second trimester RhCMV-seronegative rhesus macaque dams, including immunocompetent (n = 15), CD4+ T cell-depleted with (n = 6) and without (n = 6) RhCMV-specific polyclonal IgG infusion before infection to evaluate differences between RhCMV AF-positive and AF-negative dams. During the first 3 weeks after infection, the magnitude of RhCMV VL in maternal plasma was higher in AF-positive dams in the combined cohort, while RhCMV glycoprotein B (gB)- and pentamer-specific binding IgG responses were lower magnitude compared to AF-negative dams. However, these observed differences were driven by the CD4+ T cell-depleted dams, as there were no differences in plasma VL or antibody responses between immunocompetent AF-positive vs AF-negative dams. Overall, these results suggest that levels of neither maternal plasma viremia nor humoral responses are associated with cCMV following primary maternal infection in healthy individuals. We speculate that other factors related to innate immunity are more important in this context as antibody responses to acute infection likely develop too late to influence vertical transmission. Yet, pre-existing CMV glycoprotein-specific and neutralizing IgG may provide protection against cCMV following primary maternal CMV infection even in high-risk, immunocompromised settings.

Treatment with valacyclovir during pregnancy for prevention of congenital cytomegalovirus infection: a real-life multicenter Italian observational study

BACKGROUND

Valacyclovir is the only treatment demonstrated to be effective for the prevention of vertical transmission of cytomegalovirus within a clinical randomized, placebo-controlled trial and has been reimbursed by the Italian National Health System since December 2020.

OBJECTIVE

This study reported the results of a real-life Italian multicenter observational study on cytomegalovirus infection in pregnancy evaluating the effect of the introduction of valacyclovir in the clinical practice for the prevention of vertical transmission of cytomegalovirus.

STUDY DESIGN

The outcomes of women who received valacyclovir treatment and their fetuses or newborns were compared with those of a retrospective cohort observed between 2010 and 2020 who did not receive the antiviral treatment. The inclusion criterion was the diagnosis of cytomegalovirus primary infection occurring in the periconceptional period or up to 24 weeks of gestation. The primary outcome was the transmission by the time of amniocentesis. The secondary outcomes were termination of pregnancy, transmission at birth, symptomatic infection at birth, and a composite outcome (termination of pregnancy or transmission at birth).

RESULTS

A total of 447 pregnant women from 10 centers were enrolled, 205 women treated with valacyclovir (called the valacyclovir group, including 1 twin pregnancy) and 242 women not treated with valacyclovir (called the no-valacyclovir group, including 2 twin pregnancies). Valacyclovir treatment was significantly associated with a reduction of the diagnosis of congenital cytomegalovirus infection by the time of amniocentesis (weighted odds ratio, 0.39; 90% confidence interval, 0.22-0.68; P=.005; relative reduction of 61%), termination of pregnancy (weighted odds ratio, 0.36; 90% confidence interval, 0.17-0.75; P=.0021; relative reduction of 64%), symptomatic congenital cytomegalovirus infection at birth (weighted odds ratio, 0.17; 90% confidence interval, 0.06-0.49; P=.006; relative reduction of 83%). The treatment had no significant effect on the rate of diagnosis of congenital cytomegalovirus infection at birth (weighted odds ratio, 0.85; 90% confidence interval, 0.57-1.26; P=.500), but the composite outcome (termination of pregnancy or diagnosis of congenital cytomegalovirus infection at birth) occurred more frequently in the no-valacyclovir group (weighted odds ratio, 0.62; 90% confidence interval, 0.44-0.88; P=.024). Of note, the only symptomatic newborns with congenital cytomegalovirus infection in the valacyclovir group (n=3) were among those with positive amniocentesis. Moreover, 19 women (9.3%) reported an adverse reaction to valacyclovir treatment, classified as mild in 17 cases and moderate in 2 cases. Lastly, 4 women (1.9%) presented renal toxicity with a slight increase in creatinine level, which was reversible after treatment suspension.

CONCLUSION

Our real-life data confirm that valacyclovir significantly reduces the rate of congenital cytomegalovirus diagnosis at the time of amniocentesis with a good tolerability profile and show that the treatment is associated with a reduction of termination of pregnancy and symptomatic congenital cytomegalovirus infection at birth.

Revised Protocol for Secondary Prevention of Congenital Cytomegalovirus Infection With Valaciclovir Following Infection in Early Pregnancy

BACKGROUND

A previous randomized placebo-controlled study found valaciclovir to be effective in reducing the rate of vertical cytomegalovirus transmission from mother to fetus. The better results in women infected in the first trimester compared to the periconception period were attributed to the timing of treatment. The aim of the present study was to evaluate valaciclovir efficacy in this setting using a revised protocol.

METHODS

All pregnant women treated with valaciclovir in 2020-2022 who met the same criteria as in the original study were identified retrospectively from the database of the same medical center. Treatment, however, was initiated earlier: up to 9 weeks or 8 weeks from the presumed time of infection in women infected in the periconception period or the first trimester, respectively. The primary endpoint was rate of vertical cytomegalovirus transmission. Results were compared with the placebo arm in the previous study.

RESULTS

Among 178 women who completed valaciclovir treatment, amniocentesis was positive for cytomegalovirus in 14 women (7.9%), significantly (P < .001) lower compared with 14 of 47 (30%) in the placebo arm in the previous study. The proportion of positive amniocentesis in the valaciclovir was significantly lower than the placebo arm both among women infected in the first trimester (14/119 vs 11/23; odds ratio [OR] = 0.15; 95% confidence interval [CI]: .05-.45, P < .001), as well as among those infected in the periconception period (0/59 vs 3/24, OR = 0; 95% CI 0-.97, P = .02).

CONCLUSIONS

This study provides further evidence of the efficacy of valaciclovir in preventing vertical transmission of cytomegalovirus after primary maternal infection. Efficacy is improved with earlier treatment.

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.

Primary, Secondary, and Tertiary Prevention of Congenital Cytomegalovirus Infection

Cytomegalovirus infection is the most common congenital infection, affecting about 1% of births worldwide. Several primary, secondary, and tertiary prevention strategies are already available during the prenatal period to help mitigate the immediate and long-term consequences of this infection. In this review, we aim to present and assess the efficacy of these strategies, including educating pregnant women and women of childbearing age on their knowledge of hygiene measures, development of vaccines, screening for cytomegalovirus infection during pregnancy (systematic versus targeted), prenatal diagnosis and prognostic assessments, and preventive and curative treatments in utero.

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.

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.

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.

Neutralization Epitopes in Trimer and Pentamer Complexes Recognized by Potent Cytomegalovirus-Neutralizing Human Monoclonal Antibodies

Human cytomegalovirus (HCMV) infects 36% to almost 100% of adults and causes severe complications only in immunocompromised individuals. HCMV viral surface trimeric (gH/gL/gO) and pentameric (gH/gL/UL128/UL130/UL131A) complexes play important roles in HCMV infection and tropism. Here, we isolated and identified a total of four neutralizing monoclonal antibodies (MAbs) derived from HCMV-seropositive blood donors. Based on their reactivity to HCMV trimer and pentamer, these MAbs can be divided into two groups. MAbs PC0012, PC0014, and PC0035 in group 1 bind both trimer and pentamer and neutralize CMV by interfering with the postattachment steps of CMV entering into cells. These three antibodies recognize antigenic epitopes clustered in a similar area, which are overlapped by the epitope recognized by the known neutralizing antibody MSL-109. MAb PC0034 in group 2 binds only to pentamer and neutralizes CMV by blocking the binding of pentamer to cells. Epitope mapping using pentamer mutants showed that amino acid T94 of the subunit UL128 and K27 of UL131A on the pentamer are key epitope-associated residues recognized by PC0034. This study provides new evidence and insight information on the importance of the development of the CMV pentamer as a CMV vaccine. In addition, these newly identified potent CMV MAbs can be attractive candidates for development as antibody therapeutics for the prevention and treatment of HCMV infection. IMPORTANCE The majority of the global population is infected with HCMV, but severe complications occur only in immunocompromised individuals. In addition, CMV infection is a major cause of birth defects in newborns. Currently, there are still no approved prophylactic vaccines or therapeutic monoclonal antibodies (MAbs) for clinical use against HCMV infection. This study identified and characterized a panel of four neutralizing MAbs targeting the HCMV pentamer complex with specific aims to identify a key protein(s) and antigenic epitopes in the HCMV pentamer complex. The study also explored the mechanism by which these newly identified antibodies neutralize HCMV in order to design better HCMV vaccines focusing on the pentamer and to provide attractive candidates for the development of effective cocktail therapeutics for the prevention and treatment of HCMV infection.

Congenital cytomegalovirus infection with brainstem hemorrhage and polymicrogyria: Necropsic and histopathological findings

Congenital cytomegalovirus (CMV) infection can cause severe neurological sequelae or even fetal death. We present a 17-year-old pregnant woman with fetal CMV infection, leading to voluntary termination of pregnancy. Fetopsy demonstrated a brainstem hemorrhage and focal polymicrogyria. CMV inclusions were observed in the lung, liver, thyroid, pancreas, kidneys, adrenal, placenta, and central nervous system. Intracranial hemorrhage is a rare finding in the context of congenital CMV infection, with isolated brainstem hemorrhage being an exceptional form of presentation. Polymicrogyria appears to be a more frequent finding, although its actual incidence is unknown. Future studies are needed to determine the causal association.

Contribution of Serum Cytomegalovirus PCR to Diagnosis of Early CMV Primary Infection in Pregnant Women

(1) Background: What is the role of serum CMV PCR in the diagnosis of recent primary infection (PI) in pregnant women when IgG avidity is uninformative? (2) Methods: Retrospective cohort study to compare serum versus whole blood CMV PCR. (a) Qualitative assessment: CMV PCR was performed on 123 serum samples and 74 whole blood samples collected from 132 pregnant women with recent CMV PI. PCR positivity rate was used to calculate sensitivity in serum and whole blood. (b) Quantitative assessment: CMV PCR was performed on 72 paired samples of serum and whole blood collected on the same day from 57 patients. (3) Results: In pregnant women, PCR positivity rate was 89% for serum samples versus 100% in whole blood in the case of very recent PI (<15 days), but only 27% in serum versus 68% in whole blood for PI occurring from 6 weeks to 3 months before. Comparing CMV viral loads between serum and whole blood, we determined the limit of CMV DNA detection in serum as 3 log copies/mL (whole blood equivalent). (4) Conclusions: Serum CMV PCR is reliable in confirming PI in cases when only IgM is detected. It is therefore a valuable tool in introducing valaciclovir treatment as early as possible to prevent mother-to-child CMV transmission.

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.

Maternal immune protection against infectious diseases

The maternal immune system protects developing offspring against pathogens before birth via transplacental transfer and after birth through secreted milk. This transferred maternal immunity influences each generation's susceptibility to infections and responsiveness to immunization. Thus, boosting immunity in the maternal-neonatal dyad is a potentially valuable public health strategy. Additionally, at critical times during fetal and postnatal development, environmental factors and immune stimuli influence immune development. These "windows of opportunity" offer a chance to identify both risk and protective factors that promote long-term health and limit disease. Here, we review pre- and postpartum maternal immune factors that protect against infectious agents in offspring and how they may shape the infant's immune landscape over time. Additionally, we discuss the influence of maternal immunity on the responsiveness to immunization in early life. Lastly, when maternal factors are insufficient to prevent neonatal infectious diseases, we discuss pre- and postnatal therapeutic strategies for the maternal-neonatal dyad.

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.

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.

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.

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.

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.

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.

Immune Prophylaxis and Therapy for Human Cytomegalovirus Infection

Human Cytomegalovirus (HCMV) infection is widespread and can result in severe sequelae in susceptible populations. Primary HCMV infection of naïve individuals results in life-long latency characterized by frequent and sporadic reactivations. HCMV infection elicits a robust antibody response, including neutralizing antibodies that can block the infection of susceptible cells in vitro and in vivo. Thus, antibody products and vaccines hold great promise for the prevention and treatment of HCMV, but to date, most attempts to demonstrate their safety and efficacy in clinical trials have been unsuccessful. In this review we summarize publicly available data on these products and highlight new developments and approaches that could assist in successful translation of HCMV immunotherapies.

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.

A Trial of Hyperimmune Globulin to Prevent Congenital Cytomegalovirus Infection

BACKGROUND

Primary cytomegalovirus (CMV) infection during pregnancy carries a risk of congenital infection and possible severe sequelae. There is no established intervention for preventing congenital CMV infection.

METHODS

In this multicenter, double-blind trial, pregnant women with primary CMV infection diagnosed before 24 weeks' gestation were randomly assigned to receive a monthly infusion of CMV hyperimmune globulin (at a dose of 100 mg per kilogram of body weight) or matching placebo until delivery. The primary outcome was a composite of congenital CMV infection or fetal or neonatal death if CMV testing of the fetus or neonate was not performed.

RESULTS

From 2012 to 2018, a total of 206,082 pregnant women were screened for primary CMV infection before 23 weeks of gestation; of the 712 participants (0.35%) who tested positive, 399 (56%) underwent randomization. The trial was stopped early for futility. Data on the primary outcome were available for 394 participants; a primary outcome event occurred in the fetus or neonate of 46 of 203 women (22.7%) in the group that received hyperimmune globulin and of 37 of 191 women (19.4%) in the placebo group (relative risk, 1.17; 95% confidence interval [CI] 0.80 to 1.72; P = 0.42). Death occurred in 4.9% of fetuses or neonates in the hyperimmune globulin group and in 2.6% in the placebo group (relative risk, 1.88; 95% CI, 0.66 to 5.41), preterm birth occurred in 12.2% and 8.3%, respectively (relative risk, 1.47; 95% CI, 0.81 to 2.67), and birth weight below the 5th percentile occurred in 10.3% and 5.4% (relative risk, 1.92; 95% CI, 0.92 to 3.99). One participant in the hyperimmune globulin group had a severe allergic reaction to the first infusion. Participants who received hyperimmune globulin had a higher incidence of headaches and shaking chills while receiving infusions than participants who received placebo.

CONCLUSIONS

Among pregnant women, administration of CMV hyperimmune globulin starting before 24 weeks' gestation did not result in a lower incidence of a composite of congenital CMV infection or perinatal death than placebo. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Center for Advancing Translational Sciences; ClinicalTrials.gov number, NCT01376778.).

Guideline No. 420: Cytomegalovirus Infection in Pregnancy

OBJECTIVE

To provide an update on current recommendations for cytomegalovirus (CMV) infection during pregnancy. The objectives of this guideline are: TARGET POPULATION: Patients of child-bearing age, pregnant patients, and patients planning a pregnancy.

BENEFITS, HARMS, AND COSTS

The patient partners urged us to make awareness of preventive strategies a high priority, despite concern that discussing CMV with patients could cause unnecessary anxiety. CMV educational interventions have shown benefits from increased awareness of cCMV prevalence and preventive strategies among providers, patients, and families.

EVIDENCE

We searched MEDLINE, EMBASE, and CENTRAL databases for CMV in pregnancy. The search terms were developed using MeSH terms and keywords (Appendix). The results were filtered for articles published between January 2010 and October 2020 and systematic reviews, meta-analyses, clinical trials, and observational studies. The main inclusion criteria were pregnant patients and infants, as the target population, and CMV infection, as the diagnosis of interest. Recommendations are graded according to the U.S. Preventive Services Task Force grade of recommendations and level of certainty.

VALIDATION METHODS

We collaborated with patient partners, including members of CMV Canada (cmvcanada.com). In formulating our recommendations, we included patients' voices to add a unique and valuable perspective, thus ensuring that our recommendations are relevant to the patient-provider partnership.

INTENDED AUDIENCE

All perinatal health care providers. RECOMMENDATIONS (GRADE AND LEVEL OF CERTAINTY IN PARENTHESES).

Pregnancy and viral infections: Mechanisms of fetal damage, diagnosis and prevention of neonatal adverse outcomes from cytomegalovirus to SARS-CoV-2 and Zika virus

Some maternal infections, contracted before or during pregnancy, can be transmitted to the fetus, during gestation (congenital infection), during labor and childbirth (perinatal infection) and through breastfeeding (postnatal infection). The agents responsible for these infections can be viruses, bacteria, protozoa, fungi. Among the viruses most frequently responsible for congenital infections are Cytomegalovirus (CMV), Herpes simplex 1–2, Herpes virus 6, Varicella zoster. Moreover Hepatitis B and C virus, HIV, Parvovirus B19 and non-polio Enteroviruses when contracted during pregnancy may involve the fetus or newborn at birth. Recently, new viruses have emerged, SARS-Cov-2 and Zika virus, of which we do not yet fully know the characteristics and pathogenic power when contracted during pregnancy.

Viral infections in pregnancy can damage the fetus (spontaneous abortion, fetal death, intrauterine growth retardation) or the newborn (congenital anomalies, organ diseases with sequelae of different severity). Some risk factors specifically influence the incidence of transmission to the fetus: the timing of the infection in pregnancy, the order of the infection, primary or reinfection or chronic, the duration of membrane rupture, type of delivery, socio-economic conditions and breastfeeding. Frequently infected neonates, symptomatic at birth, have worse outcomes than asymptomatic. Many asymptomatic babies develop long term neurosensory outcomes.

The way in which the virus interacts with the maternal immune system, the maternal-fetal interface and the placenta explain these results and also the differences that are observed from time to time in the fetal‑neonatal outcomes of maternal infections. The maternal immune system undergoes functional adaptation during pregnancy, once thought as physiological immunosuppression. This adaptation, crucial for generating a balance between maternal immunity and fetus, is necessary to promote and support the pregnancy itself and the growth of the fetus. When this adaptation is upset by the viral infection, the balance is broken, and the infection can spread and lead to the adverse outcomes previously described. In this review we will describe the main viral harmful infections in pregnancy and the potential mechanisms of the damages on the fetus and newborn.

Development of a Vaccine against Human Cytomegalovirus: Advances, Barriers, and Implications for the Clinical Practice

Human cytomegalovirus (hCMV) is one of the most common causes of congenital infection in the post-rubella era, representing a major public health concern. Although most cases are asymptomatic in the neonatal period, congenital CMV (cCMV) disease can result in permanent impairment of cognitive development and represents the leading cause of non-genetic sensorineural hearing loss. Moreover, even if hCMV mostly causes asymptomatic or pauci-symptomatic infections in immunocompetent hosts, it may lead to severe and life-threatening disease in immunocompromised patients. Since immunity reduces the severity of disease, in the last years, the development of an effective and safe hCMV vaccine has been of great interest to pharmacologic researchers. Both hCMV live vaccines-e.g., live-attenuated, chimeric, viral-based-and non-living ones-subunit, RNA-based, virus-like particles, plasmid-based DNA-have been investigated. Encouraging data are emerging from clinical trials, but a hCMV vaccine has not been licensed yet. Major difficulties in the development of a satisfactory vaccine include hCMV's capacity to evade the immune response, unclear immune correlates for protection, low number of available animal models, and insufficient general awareness. Moreover, there is a need to determine which may be the best target populations for vaccine administration. The aim of the present paper is to examine the status of hCMV vaccines undergoing clinical trials and understand barriers limiting their development.

Quantifying the Burden of Congenital Cytomegalovirus Infection With Long-term Sequelae in Subsequent Pregnancies of Women Seronegative at Their First Pregnancy

BACKGROUND

In women seronegative before pregnancy, congenital cytomegalovirus (cCMV)-related sequelae are exclusively seen in those infected in the first trimester of pregnancy. Following a maternal primary infection in the first trimester, up to 30% of infected neonates suffer long-term sequelae. Maternal parity is an established risk factor of cCMV in previously seronegative women. Our objective was to quantify, in a population of women seronegative at their first pregnancy, the risk of cCMV and related sequelae following primary infections in the first trimester in subsequent pregnancies.

METHODS

There were 739 women seronegative at their first pregnancy who had at least 1 of 971 subsequent pregnancies and deliveries managed at our institution. All women had CMV immunoglobin (Ig) G and IgM testing at 11-14 weeks of each pregnancy.

RESULTS

Between 2 consecutive pregnancies, 15.6% (115/739) of women seroconverted. Of these seroconversions, 29% (33/115) occurred in the periconceptional period or in the first trimester. The risks for cCMV and related sequelae (neurologic and/or hearing loss) following a maternal infection in the first trimester were, respectively, 24- and 6-fold higher (risk ratios, 24 [95% confidence interval {CI}, 10.8-62.3] and 6 [95% CI 1.5-24], respectively) than in the general pregnant population. Of all primary maternal infections and fetal infections in the first trimester, 88% (29/33) and 92% (11/12), respectively, occurred when the inter-pregnancy interval was ≤2 years.

CONCLUSIONS

Women seronegative at their first pregnancy with a subsequent pregnancy within 2 years have the highest risk of delivering a child with cCMV-related sequelae. These women should be made aware of the risk and given the opportunity of serology screening in the first trimester.

High-Dose Cytomegalovirus (CMV) Hyperimmune Globulin and Maternal CMV DNAemia Independently Predict Infant Outcome in Pregnant Women With a Primary CMV Infection

BACKGROUND

After primary maternal cytomegalovirus (CMV) infection during pregnancy, infants are at risk for disease.

METHODS

Factors predictive of infant outcome were analyzed in a database of 304 pregnant women with primary infection. These women were enrolled between 2010 and 2017 and delivered 281 infants, of whom 108 were CMV infected. Long term follow-up occurred for 173 uninfected and 106 infected infants at age 4 years (range, 1-8 years). One hundred fifty-seven women were treated with an average of 2 doses (range, 1-6 doses) of high-dose hyperimmune globulin (HIG: 200 mg/kg/infusion). We used a regression model to define predictors of fetal infection, symptoms at birth, and long-term sequelae; 31 covariates were tested.

RESULTS

Four factors predicted fetal infection: a 1.8-fold increase (30% vs 56%) in the rate of congenital infection without HIG (adjusted odds ratio [AOR], 5.2; P < .0001), a 1.8-fold increase (32% vs 56%) associated with maternal viral DNAemia prior to HIG administration (AOR, 3.0; P = .002), abnormal ultrasounds (AOR, 59; P = .0002), and diagnosis of maternal infection by seroconversion rather than avidity (AOR, 3.3; P = .007). Lack of HIG and abnormal ultrasounds also predicted symptoms (P = .001). Long-term sequelae were predicted by not receiving HIG (AOR, 13.2; P = .001), maternal infection in early gestation (odds ratio [OR], 0.9; P = .017), and abnormal ultrasounds (OR, 7.6; P < .003). Prevalence and copy/number of DNAemia declined after HIG.

CONCLUSIONS

Maternal viremia predicts fetal infection and neonatal outcome. This may help patient counseling. High-dose HIG may prevent fetal infection and disease and is associated with the resolution of DNAemia.

Outcome of pregnancies with recent primary cytomegalovirus infection in first trimester treated with hyperimmunoglobulin: observational study

OBJECTIVE

To examine the efficacy of hyperimmunoglobulin (HIG) treatment in women with a recent primary cytomegalovirus (CMV) infection up to 14 weeks' gestation.

METHODS

This is an ongoing observational study conducted at the prenatal medicine departments of the University Hospitals of Tübingen, Bonn, Cologne and Erlangen, Germany, as well as at the Laboratory Prof. Gisela Enders and Colleagues in Stuttgart, Germany and the Institute for Medical Virology at the University of Tübingen, Tübingen, Germany. Enrolment criteria were the presence of confirmed recent primary CMV infection in the first trimester and a gestational age at first HIG administration of ≤ 14 weeks. The following inclusion criteria indicated a recent primary infection: low anti-immunoglobulin (Ig)-G levels, low anti-CMV-IgG avidity in the presence of a positive CMV-IgM test and no positive reactivity or just seroconversion anti-gB2-IgG-reactivity. HIG administration was started as soon as possible within a few days after the first visit. HIG was administered intravenously at a dose of 200 IU/kg maternal body weight and repeated every 2 weeks until about 18 weeks' gestation. The primary outcome was maternal-fetal transmission at the time of amniocentesis. Multivariate logistic regression analysis was used to determine significant covariates that could predict maternal-fetal transmission.

RESULTS

We included 149 pregnancies (153 fetuses) that completed the treatment. Median maternal age and weight were 32.0 years and 65.0 kg, respectively. Median gestational age at the time of first referral to one of the four centers was 9.4 weeks. Median anti-CMV-IgG level, anti-CMV-IgM index and CMV-IgG avidity were 5.7 U/mL, 2.5 and 22.3%, respectively. HIG treatment was started at a median gestational age of 10.6 weeks and ended at a median of 17.9 weeks. Within this time frame, HIG was administered on average four times in each patient. Amniocentesis was carried out at a median gestational age of 20.4 weeks. In 143 (93.5%) of the 153 cases, the fetus was not infected. Maternal-fetal transmission occurred in 10 cases (6.5% (95% CI, 3.2-11.7%)). On uni- and multivariate logistic regression analysis, the level of anti-IgM index was the only factor associated significantly with maternal-fetal transmission at amniocentesis. However, only four (40.0%) of the 10 cases with maternal-fetal transmission had an anti-IgM index above 11.4, which corresponds to the 95^th centile of pregnancies without transmission.

CONCLUSIONS

HIG is a treatment option to prevent maternal-fetal transmission in pregnancy with a primary CMV infection. However, HIG treatment seems to be beneficial primarily in women with a recent primary infection in the first trimester or during the periconceptional period, and when it is administered at a biweekly dose of 200 IU/kg. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Targeted mutagenesis on PDGFRα-Fc identifies amino acid modifications that allow efficient inhibition of HCMV infection while abolishing PDGF sequestration

Platelet-derived growth factor receptor alpha (PDGFRα) serves as an entry receptor for the human cytomegalovirus (HCMV), and soluble PDGFRα-Fc can neutralize HCMV at a half-maximal effective concentration (EC50) of about 10 ng/ml. While this indicates a potential for usage as an HCMV entry inhibitor PDGFRα-Fc can also bind the physiological ligands of PDGFRα (PDGFs), which likely interferes with the respective signaling pathways and represents a potential source of side effects. Therefore, we tested the hypothesis that interference with PDGF signaling can be prevented by mutations in PDGFRα-Fc or combinations thereof, without losing the inhibitory potential for HCMV. To this aim, a targeted mutagenesis approach was chosen. The mutations were quantitatively tested in biological assays for interference with PDGF-dependent signaling as well as inhibition of HCMV infection and biochemically for reduced affinity to PDGF-BB, facilitating quantification of PDGFRα-Fc selectivity for HCMV inhibition. Mutation of Ile 139 to Glu and Tyr 206 to Ser strongly reduced the affinity for PDGF-BB and hence interference with PDGF-dependent signaling. Inhibition of HCMV infection was less affected, thus increasing the selectivity by factor 4 and 8, respectively. Surprisingly, the combination of these mutations had an additive effect on binding of PDGF-BB but not on inhibition of HCMV, resulting in a synergistic 260fold increase of selectivity. In addition, a recently reported mutation, Val 242 to Lys, was included in the analysis. PDGFRα-Fc with this mutation was fully effective at blocking HCMV entry and had a drastically reduced affinity for PDGF-BB. Combining Val 242 to Lys with Ile 139 to Glu and/or Tyr 206 to Ser further reduced PDGF ligand binding beyond detection. In conclusion, this targeted mutagenesis approach identified combinations of mutations in PDGFRα-Fc that prevent interference with PDGF-BB but maintain inhibition of HCMV, which qualifies such mutants as candidates for the development of HCMV entry inhibitors.

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.

Human cytomegalovirus antagonizes activation of Fcγ receptors by distinct and synergizing modes of IgG manipulation

Human cytomegalovirus (HCMV) is endowed with multiple highly sophisticated immune evasion strategies. This includes the evasion from antibody mediated immune control by counteracting host Fc-gamma receptor (FcγR) mediated immune control mechanisms such as antibody-dependent cellular cytotoxicity (ADCC). We have previously shown that HCMV avoids FcγR activation by concomitant expression of the viral Fc-gamma-binding glycoproteins (vFcγRs) gp34 and gp68. We now show that gp34 and gp68 bind IgG simultaneously at topologically different Fcγ sites and achieve efficient antagonization of host FcγR activation by distinct but synergizing mechanisms. While gp34 enhances immune complex internalization, gp68 acts as inhibitor of host FcγR binding to immune complexes. In doing so, gp68 induces Fcγ accessibility to gp34 and simultaneously limits host FcγR recognition. The synergy of gp34 and gp68 is compelled by the interfering influence of excessive non-immune IgG ligands and highlights conformational changes within the IgG globular chains critical for antibody effector function.

Human cytomegalovirus is a type of herpes virus that rarely causes symptoms in healthy people but can cause serious complications in unborn babies and in people with compromised immune systems, such as transplant recipients.

The virus has found ways to successfully evade the immune system, and once infected, the body retains the virus for life. It deploys an arsenal of proteins that bind to antibodies, specialized proteins the immune system uses to flag virus-infected cells for destruction. This prevents certain cells of the immune system, the natural killer cells, from recognizing and destroying virus-infected cells.

These immune-evading proteins are called viral Fc-gamma receptors, or vFcγRs. While it has been previously shown that these receptors are able to evade the immune system, it remained unknown how exactly they prevent natural killer cells from recognizing infected cells.

Now, Kolb et al. show that the cytomegalovirus deploys two vFcγRs called gp34 and gp68, which work together to block natural killer cells. The latter reduces the ability of natural killer cells to bind to antibodies on cytomegalovirus-infected cells. This paves the way for gp34 to pull virus proteins from the surface of the infected cell, making them inaccessible to the immune system. Neither protein fully protects virus-infected cells on its own, but together they are highly effective.

The experiments reveal further details about how cytomegalovirus uses two defense mechanisms simultaneously to outmaneuver the immune system. Understanding this two-part viral evasion system may help scientists to develop vaccines or new treatments that can protect vulnerable people from diseases caused by the cytomegalovirus.