The Value of Hyperimmune Globulin in Pregnancies Complicated by Cytomegalovirus Infection: A Continuing Saga

Congenital Cytomegalovirus Infection: Update on Screening, Diagnosis and Treatment: Scientific Impact Paper No. 56

Cytomegalovirus (CMV) is the most common cause of viral infection in newborn babies, and affects 1 in 200 of all live born infants in high-income countries; and 1 in 71 in low- and middle-income countries. It is a major cause of hearing loss and brain damage. Women may get CMV infection for the first time during pregnancy (primary infection) or may experience 'non-primary' infection, either by reactivation of previous CMV infection or by a new infection with a different strain of the virus. The most common source of infection to pregnant women is the saliva and urine of young children. Therefore, all pregnant women, especially those in regular contact with young children, should be informed about hygiene-based measures to reduce the risks, e.g. handwashing. The UK National Screening Committee recommends against universal antenatal or newborn screening for CMV. Testing for CMV is usually offered only to women who develop symptoms of influenza, glandular fever or hepatitis (liver inflammation) during pregnancy, or for those whom a routine ultrasound scan detects fetal anomalies that suggests possible CMV infection. The risk of harm to the fetus is greatest following primary CMV infection of the woman in early pregnancy, and appears to be very low following infection after 12 weeks of pregnancy. Babies with CMV infection at birth may have jaundice, a rash, enlarged liver or spleen, a small brain, or be small for their gestational age. Around 1 in 8 babies born with CMV infection will have clinically detectable signs at birth. The rest will not have any features detectable by clinical examination alone. Therefore, all infants with CMV infection at birth should be followed up at a minimum of up to 2 years of age or later, depending upon the disease status, to check hearing and brain development. Following primary CMV infection in the first 12 weeks of pregnancy, if the woman starts taking the antiviral medicine valaciclovir (valacyclovir) it reduces the risk of the baby becoming infected. Where CMV infection of the fetus in the womb has been confirmed (by amniocentesis, for example), regular ultrasound scans should be offered every 2-3 weeks until birth. Detailed assessment of the fetal brain is an essential part of these scans. Where maternal CMV infection occurs, but fetal infection is not confirmed, repeated ultrasound scans of the fetus should be offered every 2-3 weeks until birth. In infected fetuses, as well as ultrasound scans, an MRI scan of the brain should be offered at 28-32 weeks of gestation (and sometimes repeated 3-4 weeks later) to assess for any signs of harm to the fetal brain. All babies born to women with confirmed or suspected CMV infection should be tested for CMV with a urine or saliva sample within the first 21 days of life. In newborns with symptomatic CMV infection at birth, treatment with antiviral medicine (valganciclovir or ganciclovir) can reduce hearing loss in 5 out of 6 babies, and improve long-term brain development outcomes in some. There is no licensed vaccine for CMV.

Amniotic fluid biomarkers predict the severity of congenital cytomegalovirus infection

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

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.

Recent progress in development of monoclonal antibodies against human cytomegalovirus

Human cytomegalovirus (HCMV) is a ubiquitous pathogen that can cause permanent childhood disabilities following in utero infection and life threatening diseases in immune-compromised individuals such as those post transplantation. Without an effective vaccine, small molecule antiviral drugs are routinely used in high-risk transplant recipients, but the effectiveness of which is limited by side effects and drug resistance. The potentials of antibody-based passive immune therapies alone or in combination with the small molecule antivirals to treat or prevent HCMV infection have been actively studied. In this review, we focus on the recent publications on identification and characterization of monoclonal antibodies that have the potential to be developed as anti-HCMV therapies. We review the progress in clinical evaluation of antibody-based therapies to prevent HCMV-associated diseases.

DNA Encapsidation and Capsid Assembly Are Underexploited Antiviral Targets for the Treatment of Herpesviruses

Although there are effective nucleoside analogs to treat HSV, VZV, and HCMV disease, herpesvirus infections continue to contribute to significant morbidity and mortality. Acyclovir is the drug of choice for HSV encephalopathy, yet there is an estimated 6-19% mortality rate with half of the survivors experiencing moderate to severe chronic neurological deficits. For VZV, current treatments are inadequate to prevent acute and persistent pain due to zoster. Treatment of HCMV with GCV requires close monitoring particularly in patients with impaired renal function and there are no approved treatments for congenital HCMV infections. New therapeutic options to control cytomegalovirus reactivation in bone marrow and stem cell transplant patients are needed to improve patient outcome. No successful chemotherapeutic options are available for EBV, HHV-6, 7, and 8. Drug resistance is a concern for HCMV, HSV, and VZV since approved drugs share common mechanisms of action. Targeting DNA encapsidation or capsid assembly provide additional options for the development of non-nucleoside, small molecule anti-herpesviral drugs.

SARS-CoV-2: Is it the newest spark in the TORCH?

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The SARS-CoV-2 pandemic poses under-appreciated risks during pregnancy, and perinatal infections endanger newborn outcomes.

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SARS-CoV-2 virus is transmitted in utero, although the clinical manifestations of neonatal infection are not understood.

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While the route of infection is uncertain, infection control measures should be developed to protect the newborn infant.

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Breast milk acquisition of COVID-19 is not described, and breast-feeding remains the preferred source of infant nutrition.

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The study of SARS-CoV-2 vaccines should target not only protection of the pregnant patient, but also the newborn infant.

Amid the rapidly evolving global coronavirus disease 2019 (COVID-19) pandemic that has already had profound effects on public health and medical infrastructure globally, many questions remain about its impact on child health. The unique needs of neonates and children, and their role in the spread of the virus (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) should be included in preparedness and response plans. Fetuses and newborn infants may be uniquely vulnerable to the damaging consequences of congenitally- or perinatally-acquired SARS-CoV-2 infection, but data are limited about outcomes of COVID-19 disease during pregnancy. Therefore, information on illnesses associated with other highly pathogenic coronaviruses (i.e., severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome [MERS]), as well as comparisons to common congenital infections, such as cytomegalovirus (CMV), are warranted. Research regarding the potential routes of acquisition of SARS-CoV-2 infection in the prenatal and perinatal setting is of a high public health priority. Vaccines targeting women of reproductive age, and in particular pregnant patients, should be evaluated in clinical trials and should include the endpoints of neonatal infection and disease.