Human cytomegalovirus non-primary infection during pregnancy: antibody response, risk factors and newborn outcome

Human cytomegalovirus and neonatal infection

Human cytomegalovirus is an ancient virus that has co-evolved with humans. It establishes a life-long infection in suspectable individuals for which there is no vaccination or cure. The virus can be transmitted to a developing fetus in seropositive pregnant women, and it is the leading cause of congenital infectious disease. While the majority of infected infants remain asymptomatic at birth, congenital cytomegalovirus infection can lead to substantial long-term neurodevelopmental impairments in survivors, resulting in considerable economic and social hardships. Recent discoveries regarding cytomegalovirus pathophysiology and viral replication cycles might enable the development of innovative diagnostics and therapeutics, including an effective vaccine. This Review will detail our understanding of human cytomegalovirus infection, with an in-depth discussion regarding the viral genome and transcriptome that contributes to its pathophysiology. The neonate's clinical course will also be highlighted, including maternal and neonatal testing, treatment recommendations, and long-term outcomes.

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.

Transcriptional signature of durable effector T cells elicited by a replication defective HCMV vaccine

Human cytomegalovirus (HCMV) is a leading infectious cause of birth defects and the most common opportunistic infection that causes life-threatening diseases post-transplantation; however, an effective vaccine remains elusive. V160 is a live-attenuated replication defective HCMV vaccine that showed a 42.4% efficacy against primary HCMV infection among seronegative women in a phase 2b clinical trial. Here, we integrated the multicolor flow cytometry, longitudinal T cell receptor (TCR) sequencing, and single-cell RNA/TCR sequencing approaches to characterize the magnitude, phenotype, and functional quality of human T cell responses to V160. We demonstrated that V160 de novo induces IE-1 and pp65 specific durable polyfunctional effector CD8 T cells that are comparable to those induced by natural HCMV infection. We identified a variety of V160-responsive T cell clones which exhibit distinctive "transient" and "durable" expansion kinetics, and revealed a transcriptional signature that marks durable CD8 T cells post-vaccination. Our study enhances the understanding of human T-cell immune responses to V160 vaccination.

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

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

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.

Performance evaluation of fully automated cobas® 6800 CMV PCR for the detection and quantification of cytomegalovirus DNA in neonatal urine and saliva, and adult urine, saliva, and vaginal secretion

Laboratory testing for cytomegalovirus (CMV) in bodily fluids is essential to manage congenital and prenatal CMV infection. The rapid and fully automated cobas® CMV PCR is approved only for the testing of plasma in transplant patients. To evaluate the performance of the cobas® CMV to detect and quantify CMV DNA in neonatal and adult female urine, saliva, and vaginal secretion, the limit of detection (LoD), limit of quantification (LoQ), imprecision, linearity, PCR efficiency, bias, analytical specificity, cross-reactivity, and cross-contamination of the cobas® CMV for urine, saliva, and vaginal secretion was determined. The performance of the assay was evaluated prospectively with two laboratory-developed PCR assays using neonatal and adult urine, saliva swabs, and vaginal swabs. The LoD and LoQ were 31 and 100 IU/mL, respectively, for urine, and 81 and 100 IU/mL, respectively, for vaginal secretion. The LoD and LoQ for saliva were the same (200 IU/mL). The cobas® CMV was precise (coefficient of variation ≤10%), linear (R2  ≥ 0.995), and efficient (1.07 and 1.09) between 100 and 250,000 IU/mL for the sample types. The bias and analytical specificity was <±0.30 log10 IU/mL and 100%, respectively. Cross-reactivity with non-CMV pathogens was not detected. Cross-contamination rate was 0.28%. The diagnostic accuracy, sensitivity, and specificity of the cobas® CMV for neonatal urine and saliva were ≥95.0%, ≥93.3%, and ≥90.4%, respectively. The overall percent agreement for adult urine, saliva, and vaginal secretion was 86.6%, 94.5%, and 89.4%, respectively. Taken together, the cobas® CMV demonstrated acceptable analytical and diagnostic performance, and is suitable for routine diagnostic laboratory investigation of CMV infection in neonates and adults.

Establishment and application of a point-of-care testing and diagnosis method for early immediate expression gene IE1 of cytomegalovirus in maternal urine based on isothermal amplification

BACKGROUND

Human Cytomegalovirus virus (HCMV) is a worldwide virus that causes no serious symptoms in most adults. However, HCMV infection during pregnancy, it may lead to a series of serious complications, such as hearing loss, mental retardation, visual impairment, microcephaly and developmental retardation.

AIM

The aim of this study was to develop a simple, low dependence on equipment and accurate method for HCMV detection based on the recombinase polymerase amplification (RPA) and lateral flow chromatography strip (LFS) reading.

METHODS

In order to meet the feasibility of HCMV early screening, three pairs of RPA primers were designed based on the UL123 gene encoding IE1, which was expressed immediately in the early stage of HCMV. In order to improve the specificity of the reaction and satisfy the visual detection, a specific probe was designed to insert THF site between upstream and downstream primers, fluorescein isothiocyanate (FITC) and C3spacer were used to modify the 5' end and the 3' end respectively, and Biotin was used to modify the 5' end of the reverse primer. HCMV standard strain AD169 was enriched by ARPE-19 cells culture, and its genome was extracted. The primers and probes were screened by RPA-LFS test, and the optimal reaction temperature and time were determined The specificity was verified in different viruses, bacteria and parasites. The standard curve was drawn based on the constructed recombinant plasmid of pMD18T-HCMV-UL123 and used for HCMV genomic DNA quantification and determination of the detection sensitivity. Urine samples from artificial HCMV contamination or clinical collection were prepared to evaluate the consistency with the results of real-time quantitative PCR.

RESULTS

The results showed that the primers and probes for HCMV RPA-LFS detection based on UL123 gene were successfully screened, the amplification of HCMV genomic DNA with as low as 30 copies could be completed at 37 °C within 15 min, it did not react with Human herpesvirus 1, Streptococcus pyogenes, Candida albicans, Listeria monocytogenes, Y. enterocolitica, Klebsiella Pneumoniae, Enterobacter cloacae, Citrobacter freundii, Vibrio alginnolyfificus, Vibrio parahaemolyticus, S. typhimurium, Staphylococcus aureus, Pseudomonas aeruginosa and Trichomonas vaginalis. The positive rate of PCR was 96.67 % in 30 simulated urine samples and 100 % in 127 clinical urine samples with the same UL123 gene detection.

CONCLUSIONS

To sum up, we developed a diagnostic method for HCMV based on UL123 gene combined with RPA and LFS, which is low dependent on equipment, fast, sensitive and specific, provide reference for point-of-care testing HCMV in grass-roots laboratories and remote areas.

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.

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.

Detecting human cytomegalovirus in urine, vagina and saliva: Impact of biological fluids and storage durations and temperatures on CMV DNA recovery

Sample collection, transport and storage conditions vary in the human cytomegalovirus (CMV) shedding literature. Currently, limited data exist on the impact of biological fluids and pre-analytical sample handling on the detection of CMV DNA. To evaluate CMV DNA recovery from urine, vaginal fluid and saliva stored in different conditions, adult urine, vaginal and saliva fluids and swabs, stored with or without selected nucleic acid preservation media at various durations and temperatures, was compared by polymerase chain reaction (PCR) quantitation of spiked samples and self-collected urine (n = 45) and vaginal swabs (n = 58) from CMV seropositive pregnant women. There was a time-dependent reduction in CMV DNA recovery from urine, urine diluted in phosphate-buffered saline, and saliva stored at 2-8°C, but not from urine preserved in cobas® PCR transport media (CPM) (urine/CPM). For vaginal fluid, a reduction in recovery was evident after 7 days storage at 2-8°C. CMV DNA recovery over 91 days was similar between -80°C and -20°C storage for urine and vaginal swabs preserved in CPM, and saliva swabs preserved in eNAT® PCR transport media. A statistically significant change in CMV DNA recovery after 25 months storage (median) at -80°C was not observed for self-collected urine/CPM and vaginal swab/CPM from pregnant women. Taken together, recovery of CMV DNA is dependent on fluid type and storage conditions. To improve the validity and reliability of detection at different storage durations and temperatures, the use of nucleic acid preserving transport media at the point of collection for urine, vaginal fluid and saliva may be essential.

Correlates of postnatal human cytomegalovirus transmission in term babies in the first year

Postnatal human cytomegalovirus (HCMV) infection in newborns is well characterized for preterm infants but less so for term infants. We sought to analyze the rates and routes of HCMV transmission in full-term infants during the first year of life. A cohort of 120 HCMV seropositive mothers and their 122 newborns were tested after delivery for HCMV-DNA shedding in different bodily fluids. Postnatal HCMV infection was defined as the detection of >2.5 × 102 HCMV-DNA copies/mL in infants' saliva swabs. Maternal neutralizing antibody serum titer, HCMV-specific T-cell response, and HCMV glycoprotein B immunoglobulin G on breastmilk were analyzed. HCMV shedding was detected in 67 of 120 mothers (55.8%), and 20 of 122 infants (16.4%) developed HCMV infection within the first 3 months of life. Six additional infants were infected during the first year, for a postnatal infection rate of 21.3%. Viral shedding was more frequent in breastmilk than saliva, urine, and vaginal secretions, and the mothers of infected infants showed higher levels of HCMV-DNA in milk. No association was found between the antibody levels in serum or milk and maternal viral shedding, whereas a slightly lower frequency of HCMV-specific CD4+ T-cells with long-term memory phenotype was observed in women with HCM-DNA-positive milk. About one out of five infants develop HCMV infection within the first year of life. Breastmilk appears the major route of transmission of the infection, maternal saliva has a minor role whereas the role of vaginal secretions is negligible.

The SUMOylation of Human Cytomegalovirus Capsid Assembly Protein Precursor (UL80.5) Affects Its Interaction with Major Capsid Protein (UL86) and Viral Replication

Human Cytomegalovirus Capsid Assembly Protein Precursor (pAP, UL80.5) plays a key role in capsid assembly by forming an internal protein scaffold with Major Capsid Protein (MCP, UL86) and other capsid subunits. In this study, we revealed UL80.5 as a novel SUMOylated viral protein. We confirmed that UL80.5 interacted with the SUMO E2 ligase UBC9 (58-93aa) and could be covalently modified by SUMO1/SUMO2/SUMO3 proteins. ³⁷¹Lysine located within a ψKxE consensus motif on UL80.5 carboxy-terminal was the major SUMOylation site. Interestingly, the SUMOylation of UL80.5 restrained its interaction with UL86 but had no effects on translocating UL86 into the nucleus. Furthermore, we showed that the removal of the ³⁷¹lysine SUMOylation site of UL80.5 inhibited viral replication. In conclusion, our data demonstrates that SUMOylation plays an important role in regulating UL80.5 functions and viral replication.

Human cytomegalovirus (HCMV) long-term shedding and HCMV-specific immune response in pregnant women with primary HCMV infection

Human cytomegalovirus (HCMV) shedding has been extensively investigated in newborns and in young children, however, much less is known about it in immunocompetent adults. Shedding of HCMV was investigated in saliva, vaginal secretions and urine of pregnant women experiencing primary infection along with the development of the HCMV-specific immune response. Thirty-three pregnant women shed HCMV DNA in peripheral biological fluids at least until one year after onset of infection, while in blood HCMV DNA was cleared earlier. Significantly higher levels of viral load were found in vaginal secretions compared to saliva and urine. All subjects examined two years after the onset of infection showed a high avidity index, with IgM persisting in 36% of women. Viral load in blood was directly correlated with levels of HCMV-specific IgM and inversely correlated with levels of IgG specific for the pentameric complex gH/gL/pUL128L; in addition, viral load in blood was inversely correlated with percentage of HCMV-specific CD4⁺ and CD8⁺ expressing IL-7R (long-term memory, LTM) while viral load in biological fluids was inversely correlated with percentage of HCMV-specific CD4⁺ and CD8⁺ effector memory RA⁺(T_EMRA). In conclusion, viral shedding during primary infection in pregnancy persists in peripheral biological fluids for at least one year and the development of both antibodies (including those directed toward the pentameric complex) and memory T cells are associated with viral clearance.

Prevalence, Outcome, and Prevention of Congenital Cytomegalovirus Infection in Neonates Born to Women With Preconception Immunity (CHILd Study)

BACKGROUND

Human cytomegalovirus (HCMV) is the leading infectious cause of congenital disabilities. We designed a prospective study to investigate the rate, outcome, and risk factors of congenital CMV (cCMV) infection in neonates born to immune women, and the potential need and effectiveness of hygiene recommendations in this population.

METHODS

The study was composed of 2 sequential parts: an epidemiology (part 1) and a prevention (part 2) study. Performance of part 2 depended upon a cCMV rate >0.4%. Women enrolled in part 1 did not receive hygiene recommendations. Newborns were screened by HCMV DNA testing in saliva and cCMV was confirmed by urine testing.

RESULTS

Saliva swabs were positive for HCMV DNA in 45/9661 newborns and cCMV was confirmed in 18 cases. The rate of cCMV was .19% (95% confidence interval [CI]: .11-.29%), and 3 out of 18 infants with cCMV had symptoms of CMV at birth. Age, nationality, occupation, and contact with children were similar between mothers of infected and noninfected newborns. Twin pregnancy (odds ratio [OR]: 7.2; 95% CI: 1.7-32.2; P = .037) and maternal medical conditions (OR: 3.9; 95% CI: 1.5-10.1; P = .003) appeared associated with cCMV. Given the rate of cCMV was lower than expected, the prevention part of the study was cancelled.

CONCLUSIONS

Newborns from women with preconception immunity have a low rate of cCMV, which appears to be mostly due to reactivation of the latent virus. Therefore, serological screening in childbearing age would be pivotal to identify HCMV-seropositive women, whose newborns have a low risk of cCMV.

CLINICAL TRIALS REGISTRATION

www.clinicaltrials.gov (NCT03973359).