Prenatal diagnosis of congenital human cytomegalovirus infection in amniotic fluid by nucleic acid sequence-based amplification assay

CMV-induced Hearing Loss

Congenital cytomegalovirus (cCMV) infection is the most common fetal viral infection and contributes to about 25% of childhood hearing loss by the age of 4 years. It is the leading nongenetic cause of sensorineural hearing loss (SNHL). Infants born to seroimmune mothers are not completely protected from SNHL, although the severity of their hearing loss may be milder than that seen in those whose mothers had a primary infection. Both direct cytopathic effects and localized inflammatory responses contribute to the pathogenesis of cytomegalovirus (CMV)-induced hearing loss. Hearing loss may be delayed onset, progressive or fluctuating in nature, and therefore, a significant proportion will be missed by universal newborn hearing screening (NHS) and warrants close monitoring of hearing function at least until 5-6 years of age. A multidisciplinary approach is required for the management of hearing loss. These children may need assistive hearing devices or cochlear implantation depending on the severity of their hearing loss. In addition, early intervention services such as speech or occupational therapy could help better communication, language, and social skill outcomes. Preventive measures to decrease intrauterine CMV transmission that have been evaluated include personal protective measures, passive immunoprophylaxis and valacyclovir treatment during pregnancy in mothers with primary CMV infection. Several vaccine candidates are currently in testing and one candidate vaccine in phase 3 trials. Until a CMV vaccine becomes available, behavioral and educational interventions may be the most effective strategy to prevent maternal CMV infection.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Congenital Human Cytomegalovirus Infection Inducing Sensorineural Hearing Loss

Human cytomegalovirus (HCMV) is the primary cause of congenital infections. Despite its clinical significance, congenital HCMV infection is frequently overlooked clinically since most affected infants are asymptomatic. Sensorineural hearing loss (SNHL) is one of the most widely known disorders caused by congenital HCMV infection. The potential mechanism, however, remains unknown to date. The mechanism by which congenital HCMV infection induces sensorineural deafness has been partly characterized, leading to advancements in diagnosis, therapy, and prevention strategies. HCMV-induced hearing loss primarily involves immune responses, the release of inflammatory factors by natural killer (NK) cells, apoptosis of cochlear spiral ganglion, and potential changes due to vascular dysfunction. The diagnosis of HCMV induced SNHL includes serological examination to mothers, imaging, and amniotic fluid examination. Ganciclovir, mainly used for antiviral therapy and behavioral prevention, can, to some degree, prevent congenital HCMV infection. The role of HCMV infection in hearing loss needs further investigation since the mechanism of hearing loss caused by cytomegalovirus infection is not well understood. Although some advancement has been made in diagnosing and treating SNHL, more improvement is needed. A comprehensive understanding of cytomegalovirus’s pathogenesis is of key importance for preventing, diagnosing, and treating SNHL.

Prevalence of congenital cytomegalovirus infection in symptomatic newborns under 3 weeks in Tehran, Iran

Background

Cytomegalovirus (CMV) is a common cause of congenital infection worldwide and infants with symptomatic congenital CMV (cCMV) infection are at significantly increased risk of developing adverse long-term outcomes. This study aimed to determine the prevalence of cCMV infections in symptomatic infants under 3 weeks in Tehran, IRAN and to evaluate the usefulness of serologic markers in these neonates.

Methods

Urine and serum samples of 100 symptomatic infants, under 3 weeks old, with clinical signs referred to Tehran medical centers from June 2013 to December 2014, were collected and tested for CMV-DNA and IgG/IgM antibody titers by PCR and ELISA, respectively.

Results

CMV-DNA was detected in urine of 58 cases, whereas only 20 cases had detectable CMV-IgM titers. All CMV-IgM positive cases excreted CMV-DNA through their urine. Of the 100 patients, only 59 had CMV-IgG antibody and CMV-DNA was found in the urine of only 40 of them.

Conclusions

We conclude that CMV is an important etiologic agent of congenital infections in symptomatic infants in Tehran, IRAN (prevalence: 58%) and CMV-DNA detection immediately after delivery is recommended for early treatment and reduction of post infection problems. Furthermore, our study showed that the serologic markers are unreliable for diagnosis of cCMV infection in infants. This is the first report of cCMV prevalence in symptomatic congenital infections in Iran showing similarity with the world averages.

Prenatal diagnosis of congenital cytomegalovirus infection in 115 cases: a 5 years' single center experience

OBJECTIVE

The objective of this study is to investigate the diagnostic value of invasive prenatal diagnosis (PD) of congenital cytomegalovirus (CMV) infection from amniotic fluid (AF) and fetal blood (FB).

METHODS

A retrospective study was conducted on 115 pregnancies with CMV primary infection. A total of 111 AF and 106 FB samples were investigated for various virological and non-virological markers. Detailed ultrasound examinations were performed at time of PD.

RESULTS

Overall sensitivity of CMV PCR in FB (75.6%; 95%CI 60-87) and AF (72.7%; 95%CI 57-85) was comparable. In women with amniocentesis >8 weeks between seroconversion and PD, we did not observe significant differences between amniocentesis performed ≥17 + 0 (sensitivity 90.9%; 95%CI 71-99) and ≥20 + 0 gestational weeks (sensitivity 90.0%; 95%CI 68-99). Virological markers in FB were higher in symptomatic compared with asymptomatic fetuses (p < 0.05). No significant differences were observed for non-virological markers. However, platelet counts <120 × 10e9/L and beta-2 microglobulin values >14 mg/L were more frequently found in fetuses with severe ultrasound abnormalities compared with fetuses with no or mild abnormalities (p < 0.001).

CONCLUSION

Optimal timing of amniocentesis in women with primary infection in early gestation should be reevaluated in a prospective study. Analysis of FB markers may be beneficial in the individual management of pregnant women with confirmed congenital CMV infection. © 2017 John Wiley & Sons, Ltd.

Clinical Implications for Children Born With Congenital Cytomegalovirus Infection Following a Negative Amniocentesis

BACKGROUND

Recently, congenital cytomegalovirus (cCMV) infection was reported irrespective of a negative amniotic fluid prenatal analysis for cytomegalovirus (CMV). The question of whether this phenomenon represents low sensitivity of the test or late development of fetal infection (after amniocentesis) was discussed, but not answered. However, if late transmission is the rule, then infants born with cCMV after negative amniocentesis would be expected to carry better prognosis than those who tested positive.

METHODS

Data of all infants with cCMV infection, followed in 2 pediatric centers from 2006 to 2015, were reviewed. Infant outcome after birth of symptomatic vs asymptomatic disease was compared with infants born after a negative amniocentesis (study group) and those with a positive amniocentesis (control group).

RESULTS

Amniocentesis was performed in 301 pregnancies of our cohort of infants with cCMV and was negative for CMV in 47 (15.6%). There were fewer symptomatic cCMV neonates in the study group than in the control group (4.3% vs 25%; P < .001). Hearing impairment at birth was also less frequent in the study group (2.2% vs 17.4%; P = .012). None of the children in the study group had neurologic sequelae at long-term follow up, compared with 13 (14.1%) in the control group (P < .001).

CONCLUSIONS

Although negative amniocentesis does not exclude cCMV, infants with cCMV born after a negative amniocentesis seldom present with mild clinical symptoms or cerebral ultrasound features at birth. These children also have a very good long-term outcome. Our findings support the theory of a late development of fetal infection, after the time of the amniocentesis.

Ex vivo model of congenital cytomegalovirus infection and new combination therapies

INTRODUCTION

Congenital human cytomegalovirus (HCMV) infection is a major public health problem due to severe sequelae in the fetus and newborns. Currently, due to their toxicity anti-CMV treatments cannot be administered to pregnant women. We thus developed an ex vivo model of 1(st) trimester placental CMV infection to observe the route of infection across the placenta and to test the efficacy of various new drugs targeting different stages of viral cycle.

METHODS

After validation of the viability of floating villi explants by ELISA β-HCG, the kinetics of placental infection were determined by immunochemistry and qPCR in this ex vivo model. Antiviral susceptibility was determined in vitro using focus reduction assay and by qPCR in the ex vivo model.

RESULTS

The ex vivo model showed viral infection in trophoblasts and mesenchymal space of floating villi. In vitro, antiviral combinations of maribavir with baïcalein or artesunate inhibited viral infection by more than 90%. On the other hand, in ex vivo model, infection was reduced by 40% in presence of maribavir and artesunate. The synergistic effect observed in vitro was not observed ex vivo.

DISCUSSION

This model allowed us to understand the CMV spread in 1(st) trimester floating villi better and to analyze the anti-CMV efficacy and toxicity of new drugs that could be administered to pregnant women, either alone or in combination.

CONCLUSIONS

Such an ex vivo model could be applied to other viruses such as rubella or parvovirus B19 and in new drug development.

Congenital cytomegalovirus infection: clinical outcome

Congenital cytomegalovirus (CMV) infection is a leading cause of hearing loss and neurologic disabilities in children worldwide. Infants with symptomatic congenital CMV infection at birth are at significantly increased risk for developing adverse long-term outcomes. The vast majority of infants with congenital CMV infection have no clinical findings at birth (asymptomatic infants), and about 10%-15% of these children develop long-term sequelae. Currently, predictors of adverse outcome in asymptomatic congenital CMV infection are not known, and it is important that future studies address this issue.

Comparison of automated nucleic acid extraction methods for the detection of cytomegalovirus DNA in fluids and tissues

Testing for cytomegalovirus (CMV) DNA is increasingly being used for specimen types other than plasma or whole blood. However, few studies have investigated the performance of different nucleic acid extraction protocols in such specimens. In this study, CMV extraction using the Cell-free 1000 and Pathogen Complex 400 protocols on the QIAsymphony Sample Processing (SP) system were compared using bronchoalveolar lavage fluid (BAL), tissue samples, and urine. The QIAsymphonyAssay Set-up (AS) system was used to assemble reactions using artus CMV PCR reagents and amplification was carried out on the Rotor-Gene Q. Samples from 93 patients previously tested for CMV DNA and negative samples spiked with CMV AD-169 were used to evaluate assay performance. The Pathogen Complex 400 protocol yielded the following results: BAL, sensitivity 100% (33/33), specificity 87% (20/23); tissue, sensitivity 100% (25/25), specificity 100% (20/20); urine, sensitivity 100% (21/21), specificity 100% (20/20). Cell-free 1000 extraction gave comparable results for BAL and tissue, however, for urine, the sensitivity was 86% (18/21) and specimen quantitation was inaccurate. Comparative studies of different extraction protocols and DNA detection methods in body fluids and tissues are needed, as assays optimized for blood or plasma will not necessarily perform well on other specimen types.

Primary cytomegalovirus infection in pregnant Egyptian women confirmed by cytomegalovirus IgG avidity testing

OBJECTIVE

To determine the frequency of primary cytomegalovirus (CMV) infection in pregnant Egyptian women using CMV IgG avidity testing.

SUBJECTS AND METHODS

A cross-sectional study was conducted at Suez Canal University Hospital, Ismailia, Egypt. A total of 546 pregnant women, presenting for routine antenatal screening, were tested for CMV IgG and IgM using a commercially available enzyme-linked immunosorbent assay (ELISA). Sera from CMV IgM-positive women were tested by CMV IgG avidity assay.

RESULTS

All the 546 pregnant women were seropositive for anti-CMV IgG. Of the 546 women, 40 (7.3%) were positive or equivocal for IgM antibodies. All sera from the 40 women (IgG+/IgM+) showed a high or intermediate CMV IgG avidity index. Of the 40 women, 23 (57.5%) were in the second or third trimesters of pregnancy and had their first-trimester blood retrieved, and the tested CMV IgG avidity assay showed a high avidity index.

CONCLUSION

Women who were IgM positive had no primary CMV infection in the index pregnancy as evidenced by the high CMV IgG avidity testing.

The "silent" global burden of congenital cytomegalovirus

Human cytomegalovirus (CMV) is a leading cause of congenital infections worldwide. In the developed world, following the virtual elimination of circulating rubella, it is the commonest nongenetic cause of childhood hearing loss and an important cause of neurodevelopmental delay. The seroprevalence of CMV in adults and the incidence of congenital CMV infection are highest in developing countries (1 to 5% of births) and are most likely driven by nonprimary maternal infections. However, reliable estimates of prevalence and outcome from developing countries are not available. This is largely due to the dogma that maternal preexisting seroimmunity virtually eliminates the risk for sequelae. However, recent data demonstrating similar rates of sequelae, especially hearing loss, following primary and nonprimary maternal infection have underscored the importance of congenital CMV infection in resource-poor settings. Although a significant proportion of congenital CMV infections are attributable to maternal primary infection in well-resourced settings, the absence of specific interventions for seronegative mothers and uncertainty about fetal prognosis have discouraged routine maternal antibody screening. Despite these challenges, encouraging results from prototype vaccines have been reported, and the first randomized phase III trials of prenatal interventions and prolonged postnatal antiviral therapy are under way. Successful implementation of strategies to prevent or reduce the burden of congenital CMV infection will require heightened global awareness among clinicians and the general population. In this review, we highlight the global epidemiology of congenital CMV and the implications of growing knowledge in areas of prevention, diagnosis, prognosis, and management for both low (50 to 70%)- and high (>70%)-seroprevalence settings.

Congenital cytomegalovirus infection following antenatal negative diagnostic amniotic fluid analysis - a single center experience

OBJECTIVE

To determine the perinatal outcome of confirmed congenital cytomegalovirus (CMV) infection despite a negative prenatal amniotic-fluid analysis.

METHODS

A retrospective cohort study of all neonates diagnosed with congenital CMV infection from January 2006 to December 2011 despite negative results on polymerase chain reaction and shell's vial assays of amniotic fluid. Data were collected on all neonates by physical examination, blood work-up (complete blood count, bilirubin, liver enzymes), fundoscopy, brainstem evoked response (BSER), and brain ultrasound, at birth and during follow-up in the neonatal period.

RESULTS

The study group included 10 patients with primary congenital CMV infection during pregnancy. Follow-up time ranged from 1 to 62 months (median, 17 months). Four patients had consistently normal findings throughout follow-up, and three developed mild hepatosplenomegaly (1-32 months). In the remaining four offspring, brain ultrasound preformed after birth revealed lenticular striated vasculopathy (LSV) and in three of them the BSER test showed decreased hearing ability. Treatment with ganciclovir/valganciclovir was administered at age of 2 weeks, 2, 18, and 32 months. The BSER normalized after 9 and 12 months of treatment in two patients for whom follow-up data were available.

CONCLUSION

Negative findings on amniotic-fluid tests for CMV do not rule out neonatal infection with clinical morbidity.

Clinical predictive value of real-time PCR quantification of human cytomegalovirus DNA in amniotic fluid samples

The aim of this study was to evaluate the diagnostic reliability and prognostic significance of the quantification of cytomegalovirus (CMV) DNA in amniotic fluid (AF). We retrospectively reviewed the results for 282 amniotic fluid samples that had been tested for CMV by a quantitative real-time PCR. We observed three cases in which no CMV genomes were detected in the AF but in which the children were nevertheless congenitally infected. Hence, we conclude that a negative result by PCR for CMV in AF cannot rule out the possibility of congenital infection. No false-positive PCR results were observed. A correlation between the CMV viral load in AF and the fetal and neonatal outcomes could not be demonstrated in our study. Instead, a correlation was found between the CMV viral load and the gestational age at the time of amniocentesis.

Human herpes viruses in pregnancy: cytomegalovirus, Epstein-Barr virus, and varicella zoster virus

Viruses of the human herpesvirus family can have profound effects on pregnancy. Primary maternal infection with cytomegalovirus (CMV) and varicella during pregnancy has been associated with fetal abnormalities and neonatal disease. Public awareness of the role of cytomegalovirus in the etiology of developmental disorders and chronic disabilities needs to increase. With time, we may see new interventions for treatment of infected pregnant women and prevention of long-term effects. Attention must be focused on development of a safe and effective vaccine. With the introduction of an efficacious varicella vaccine, the rate of varicella in pregnancy is expected to decrease dramatically. Physicians caring for women have the opportunity to prevent the complications of varicella by identifying and vaccinating susceptible women.

The detection of CMV in amniotic fluid and cervicovaginal smear samples by real-time PCR assay in prenatal diagnosis

OBJECTIVE

There is no specific antiviral therapy or a vaccine, which could be safely administered to the pregnant women with primary human cytomegalovirus (CMV) infection. Therefore, prenatal diagnosis has a critical role in the management of pregnancy, complicated by this disease. In this study, we investigated the prevalence and clinical consequences of human CMV infection from cervicovaginal smear and amniotic fluid samples of pregnant women by using real-time polymerase chain reaction (RT-PCR) assay, in one of the Obstetrics and Gynecology outpatient clinics of Turkey. The identification of reliable prognostic markers of fetal disease remains the main purpose and a major challenge on this issue.

METHODS

Two hundred and six samples, of which 135 were cervicovaginal smear and 71 were amniotic fluid, were enrolled in the study. The DNAs of the samples were extracted by using Roche Diagnostic (Roche, Germany) kit and amplifications of these DNAs were studied by using Light-Cycler system (Roche Germany) as being quantitative. Anti-CMV IgM antibodies in the samples were studied by both MEIA (Imx system, Abbot Laboratories, USA) and a commercial ELISA kit (Radim SPA, Italy) while anti-CMV IgG antibodies were studied by MEIA (Axsym system, Abbot Laboratories, USA).

RESULTS

Human CMV DNA was found to be positive in 1.5% (2 in 135) of cervicovaginal smear and 1.4% (1 in 71) of amniotic fluid samples by RT-PCR. IgM and IgG were found to be negative in all of the cervicovaginal smear samples by both MEIA and ELISA, while IgG antibody was found to be positive in only one of the amniotic fluid samples by MEIA.

CONCLUSION

With RT-PCR assay, we have found the prevalence of human CMV in pregnant women similar to epidemiologic reports, which have been described earlier. Whereas the fetus with positive amniotic fluid in favor of human CMV had an intrauterine growth restriction resulted in intrauterine exitus, no symptoms were observed in the infants of the other two pregnant women with positive RT-PCR results. The fact that the clinical consequence of the newborn whose amniotic fluid evaluation revealed human CMV infection by RT-PCR made us think that this molecular diagnosis method may be a reliable assay in prenatal diagnosis of this pathogen.

Congenital cytomegalovirus infection: outcome and diagnosis

Cytomegalovirus (CMV) is the most common congenital infection in humans and an important cause of morbidity and mortality in immunocompromised hosts. Congenital CMV infection occurs in approximately 0.5 to 1 percent of all newborns in the United States and can result in significant neurological sequelae. The gold standard for diagnosing congenital CMV infection is isolation of the virus from infants within the first 2 weeks of life through conventional or rapid cell culture techniques. Newer molecular diagnostic methods to diagnose congenital CMV infection, including the nucleic acid amplification of viral DNA from the peripheral blood of infants, are being investigated, and the preliminary results show promise. However, more work must be done to standardize and validate these methods before they can be used routinely in establishing the diagnosis of congenital CMV infection.

Human cytomegalovirus: clinical aspects, immune regulation, and emerging treatments

After initial infection, human cytomegalovirus remains in a persistent state with the host. Immunity against the virus controls replication, although intermitent viral shedding can still take place in the seropositive immunocompetent person. Replication of cytomegalovirus in the absence of an effective immune response is central to the pathogenesis of disease. Therefore, complications are primarily seen in individuals whose immune system is immature, or is suppressed by drug treatment or coinfection with other pathogens. Although our increasing knowledge of the host-virus relationship has lead to the development of new pharmacological strategies for cytomegalovirus-associated infections, these strategies all have limitations-eg, drug toxicities, development of resistance, poor oral bioavailability, and low potency. Immune-based therapies to complement pharmacological strategies for the successful treatment of virus-associated complications should be prospectively investigated.

Diagnosis of fetal infections

PURPOSE OF REVIEW

The purpose of this review is to present recent developments in the prenatal diagnosis of the most clinically relevant congenital infections.

RECENT FINDINGS

Immunoglobin G avidity testing can help to differentiate between recent or prior infection. A combination of tests, including serology, avidity and polymerase chain reaction, may be necessary to improve accuracy of diagnosis. The interval between exposure to an infectious agent and prenatal testing can be critical to the interpretation of the test result.

SUMMARY

This review reinforces the need for accurate testing to guide appropriate counseling and individual fetal risk assessment. The findings of viral-specific antibodies or sonographic abnormalities do not accurately predict the severity or outcome of fetal infection. Further research is necessary to determine the pathogenesis of transplacental viral transmission and thereby allow us to target prevention strategies.