Risk of congenital disease in 46 infected fetuses according to gestational age of primary human cytomegalovirus infection in the mother

An Overview of Cytomegalovirus Infection in Pregnancy

The objective of this review was to bring to attention cytomegalovirus (CMV) infection during pregnancy, taking into consideration all relevant aspects, such as maternal diagnosis, fetal infection and prevention, prenatal diagnosis, and postnatal prognosis. A literature review was performed regarding adult and congenital infection. General information regarding this viral infection and potential related medical conditions was provided, considering the issues of maternal infection during pregnancy, transmission to the fetus, and associated congenital infection management. Prenatal diagnosis includes maternal serum testing and the confirmation of the infection in amniotic fluid or fetal blood. Additionally, prenatal diagnosis requires imaging techniques, ultrasound, and complementary magnetic resonance to assess cortical and extracortical anomalies. Imaging findings can predict both fetal involvement and the postnatal prognosis of the newborn, but they are difficult to assess, even for highly trained physicians. In regard to fetal sequelae, the early diagnosis of a potential fetal infection is crucial, and methods to decrease fetal involvement should be considered. Postnatal evaluation is also important, because many newborns may be asymptomatic and clinical anomalies can be diagnosed when sequelae are permanent.

Cytomegalovirus Infection and Inflammation in Developing Brain

Human cytomegalovirus (HCMV) is a highly prevalent herpesvirus that can cause severe disease in immunocompromised individuals and immunologically immature fetuses and newborns. Most infected newborns are able to resolve the infection without developing sequelae. However, in severe cases, congenital HCMV infection can result in life-threatening pathologies and permanent damage of organ systems that possess a low regenerative capacity. Despite the severity of the problem, HCMV infection of the central nervous system (CNS) remains inadequately characterized to date. Cytomegaloviruses (CMVs) show strict species specificity, limiting the use of HCMV in experimental animals. Infection following intraperitoneal administration of mouse cytomegalovirus (MCMV) into newborn mice efficiently recapitulates many aspects of congenital HCMV infection in CNS. Upon entering the CNS, CMV targets all resident brain cells, consequently leading to the development of widespread histopathology and inflammation. Effector functions from both resident cells and infiltrating immune cells efficiently resolve acute MCMV infection in the CNS. However, host-mediated inflammatory factors can also mediate the development of immunopathologies during CMV infection of the brain. Here, we provide an overview of the cytomegalovirus infection in the brain, local immune response to infection, and mechanisms leading to CNS sequelae.

Elimination of human cytomegalovirus DNA degradation in urine

Congenital cytomegalovirus infection (cCMVi) is an important cause of sensorineural hearing loss in newborns. Detection of human cytomegalovirus (HCMV) DNA in urine has been used to screen for cCMVi in newborns. However, the matrix effect of urine on HCMV DNA detection is unclear. To evaluate the matrix effect of urine on HCMV DNA detection and optimize the sample process strategy to eliminate or minimize the impact of urine on HCMV DNA detection, DNA in spiked samples was extracted using different DNA extraction methods, and urine samples that could inhibit HCMV DNA detection were mixed to evaluate the inhibitory substances, inhibitory mechanism, and elimination of the inhibitory effect. The optimal urine sample process strategy was evaluated using 42 adult female urine samples and 42 newborn urine samples spiked with HCMV. Some urine samples were found to inhibit HCMV DNA detection due to DNA degradation. The addition of ≥5 mM EDTA to the urine before extraction eliminated the inhibitory effect of urine and did not affect the detection results of urine exhibiting no inhibition. Of the 42 adult female and 42 newborn urine samples, four and two samples, respectively, could inhibit HCMV DNA detection. However, the inhibitory effects of these six urine samples were eliminated after the addition of EDTA. The collective results indicate that the addition of EDTA can completely eliminate the impact of inhibitors present in urine on HCMV DNA extraction and improve the detection of HCMV in urine.

Outcome of fetuses with congenital cytomegalovirus infection and normal ultrasound at diagnosis: systematic review and meta-analysis

OBJECTIVE

To report the outcome of fetuses with congenital cytomegalovirus (CMV) infection and normal ultrasound at the time of diagnosis, and to evaluate the rate of an additional anomaly detected only on magnetic resonance imaging (MRI).

METHODS

Medline, EMBASE, CINAHL and Cochrane databases were searched for studies reporting on the outcome of fetuses with congenital CMV infection. Inclusion criteria were fetuses with confirmed CMV infection and normal ultrasound assessment at the time of the initial evaluation. The outcomes observed were an anomaly detected on a follow-up ultrasound scan, an anomaly detected on prenatal MRI but missed on ultrasound, an anomaly detected on postnatal assessment but missed prenatally, perinatal mortality, symptomatic infection at birth, neurodevelopmental outcome and hearing and visual deficits. Neurodevelopmental outcome was assessed only in cases of isolated CMV infection confirmed at birth. Subgroup analysis was performed according to the trimester in which maternal infection occurred. Random-effects meta-analysis of proportions was used to analyze the data.

RESULTS

Twenty-six studies were included, comprising 2603 fetuses with congenital CMV infection, of which 1178 (45.3%) had normal ultrasound at the time of diagnosis and were included in the analysis. The overall rate of an associated central nervous system (CNS) anomaly detected on a follow-up ultrasound scan was 4.4% (95% CI, 1.4-8.8%) (32/523; 15 studies), while the rates of those detected exclusively on prenatal MRI or on postnatal imaging were 5.8% (95% CI, 1.9-11.5%) (19/357; 11 studies) and 3.2% (95% CI, 0.3-9.0%) (50/660; 17 studies), respectively. The rate of an associated extra-CNS anomaly detected on a follow-up ultrasound scan was 2.9% (95% CI, 0.8-6.3%) (19/523; 15 studies), while the rates of those detected exclusively on MRI or on postnatal imaging were 0% (95% CI, 0.0-1.7%) (0/357; 11 studies) and 0.9% (95% CI, 0.3-1.8%) (4/660; 17 studies), respectively. Intrauterine death and perinatal death each occurred in 0.7% (95% CI, 0.3-1.4%) (2/824; 23 studies) of cases. In cases without an associated anomaly detected pre- or postnatally, symptomatic infection was found in 1.5% (95% CI, 0.7-2.7%) (6/548; 19 studies) of infants, the overall rate of a neurodevelopmental anomaly was 3.1% (95% CI, 1.6-5.1%) (16/550; 19 studies), and hearing problems affected 6.5% (95% CI, 3.8-10.0%) (36/550; 19 studies) of children. Subanalyses according to the trimester in which maternal infection occurred were affected by the very small number of included cases and lack of comparison of the observed outcomes in the original studies. Compared with fetuses infected in the second or third trimester, those infected in the first trimester had a relatively higher risk of having an additional anomaly detected on follow-up ultrasound or MRI, abnormal neurodevelopmental outcome and hearing problems.

CONCLUSIONS

In fetuses with congenital CMV infection in which no anomalies are detected on prenatal ultrasound or MRI, the risk of adverse postnatal outcome is lower than that reported previously in the published literature when not considering the role of antenatal imaging assessment. The results from this review also highlight the potential role of MRI, even in fetuses with no anomalies detected on ultrasound, as an anomaly can be detected exclusively on MRI in about 6% of cases. The findings from this study could enhance prenatal counseling of pregnancies with congenital CMV infection with normal prenatal imaging. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Pitfalls in the Serological Diagnosis of Primary Human Cytomegalovirus Infection in Pregnancy Due to Different Kinetics of IgM Clearance and IgG Avidity Index Maturation

Primary infection occurs when seronegative women are infected by human cytomegalovirus (HCMV). Diagnosis of primary infection is based on the following: antibody seroconversion, presence of IgM and low IgG avidity index (AI), and presence of DNAemia. The kinetics of HCMV-specific IgM antibody and maturation of AI might be very rapid or long-lasting during primary infection, which makes serological diagnosis insidious. The aims of this study were as follows: (i) to report atypical kinetics of HCMV-specific IgM antibody and AI early after onset of primary HCMV infection in a population of pregnant women, and (ii) to assess the frequency of such results. Altogether, 1309 sequential serum samples collected from 465 pregnant women with primary HCMV infection were included in the study. As a general rule, using the LIAISON^®CMVIgMII and LIAISON^®CMVIgGAvidityII assays, virus-specific IgM antibody levels decreased, while IgG AI increased over time during the first three months after infection onset. However, early clearance of IgM antibody and/or early IgG AI maturation occurred in 46/426 (10.7%) women. In more details, 20/426 (4.7%) and 26/418 (6.2%) women had undetectable IgM antibody or high IgG AI, respectively, when tested within 1-3 months after well-defined infection onset. Twenty sera from as many women with high IgG AI by the LIAISON assay were further tested for IgG AI by VIDAS^®CMVIgGAvidityII and Mikrogen recomLineCMVIgG Avidity assays. Comparable results were obtained with VIDAS, whereas 14/20 sera gave low AI with the Mikrogen assay. In conclusion, about 11% of pregnant women undergoing a primary HCMV infection showed misleading serological results. Additional and appropriate testing might help in reducing the risk of missing HCMV primary infection in pregnancy. Furthermore, preconceptional testing should be strongly recommended.

Determination of anti-p52 IgM and anti-gB IgG by ELISA as a novel diagnostic tool for detection of early and late phase of primary human cytomegalovirus infections during pregnancy

BACKGROUND

Dating of primary human cytomegalovirus (HCMV) infection in pregnancy is crucial to define whether infection occurred before or during pregnancy and at which gestational age.

OBJECTIVE

The aim of this study was to identify a diagnostic strategy for determination of early, intermediate and late phase of HCMV primary infection during pregnancy.

STUDY DESIGN

Sequential serum samples from 40 pregnant women with defined onset of HCMV primary infection were tested retrospectively for IgM, IgG and IgG avidity against whole HCMV lysate, along with anti-p52 IgM and anti-gB IgG (Euroimmun AG).

RESULTS

Anti-HCMV IgM were positive in all samples collected within the first 2 months, then decreased remaining weakly positive in about 40% of samples collected within 6-12 months after infection. Anti-p52 IgM followed similar kinetics but decreased earlier, remaining weakly positive only in 20% of late samples. Anti-HCMV IgG were positive in all samples and showed variable kinetics. Their avidity increased from low levels, observed within 2 months, to intermediate/high levels from 4 months onwards. Anti-gB IgG increased over time following kinetics similar to anti-HCMV IgG avidity. By combining results of anti-HCMV IgM plus IgG avidity, and confirming them with anti-p52 IgM plus anti-gB IgG as second-line assays, the early (within 2-3 months) and late (after 3 months) phases of HCMV infection were satisfactorily defined, whereas the intermediate phase overlapped with the beginning of the late phase.

CONCLUSION

Anti-p52 IgM and anti-gB IgG provide additional tools besides classical anti-HCMV IgM, IgG and IgG avidity in dating HCMV primary infections.

The use of fetal neurosonography and brain MRI in cases of cytomegalovirus infection during pregnancy: A retrospective analysis with outcome correlation

OBJECTIVE

To analyze ultrasound (US) and magnetic resonance imaging (MRI) results and developmental outcome in cases of maternal primary cytomegalovirus (CMV) infection during pregnancy.

METHODS

We retrospectively reviewed the results of fetal neurosonography and brain MRI of CMV-infected fetuses (Group 1). Cases of maternal infection in which the fetal status was unknown, and subsequently had a negative CMV postnatal urine analysis, were independently analyzed (Group 2). Imaging results were classified as follows: positive, negative, or inconclusive. Developmental landmarks were followed up.

RESULTS

Eighty-one women were included in the study: 48 (59.2%) in Group 1 and 33 (40.8%) in Group 2. In Group 1, termination of pregnancy was performed in 8 cases (16.7%) following the diagnosis of brain abnormalities. Among the remaining cases, concordance rate between US and MRI was 78%. False negative rates for US and MRI were 5.5% and 6.4%, respectively (hearing deficits). For MRI, we found 17.5% of false positive/inconclusive results, while for the US, we found 5% of inconclusive results. In Group 2, false positive rates for US and MRI were 6.5% and 12.9%, respectively.

CONCLUSIONS

Adding MRI in CMV-infected cases with a normal neurosonographic follow-up should be weighed against a nonnegligible rate of false positive and inconclusive findings.

Maternal and fetal cytomegalovirus infection: diagnosis, management, and prevention

Congenital cytomegalovirus infection is a major cause of central nervous system and sensory impairments that affect cognition, motor function, hearing, language development, vestibular function, and vision. Although the importance of congenital cytomegalovirus infection is readily evident, the vast majority of maternal and fetal infections are not identified, even in developed countries. Multiple studies of prenatal cytomegalovirus infections have produced a body of knowledge that can inform the clinical approach to suspected or proven maternal and fetal infection. Reliable diagnosis of cytomegalovirus infection during pregnancy and accurate diagnosis of fetal infection are a reality. Approaches to preventing the transmission of cytomegalovirus from mother to fetus and to the treatment of fetal infection are being studied. There is evidence that public health approaches based on hygiene can dramatically reduce the rate of primary maternal cytomegalovirus infections during pregnancy. This review will consider the epidemiology of congenital cytomegalovirus infection, the diagnosis and management of primary infection during pregnancy, and approaches to preventing maternal infection.

Human cytomegalovirus UL141 protein interacts with CELF5 and affects viral DNA replication

Human cytomegalovirus (HCMV) infection is the primary viral cause of congenital abnormalities and mental retardation in newborns. The HCMV UL141‑encoded glycoprotein has been previously revealed to inhibit the cell‑surface expression of cluster of differentiation (CD)155, CD122, tumor necrosis factor‑related apoptosis‑inducing ligand death (TRAIL)‑receptor 1 (R1) and TRAIL‑receptor 2 (R2), thus protecting virally‑infected cells by allowing them to escape natural killer cell‑mediated cytotoxicity. The present study investigated the interaction between HCMV UL141 and human fetal brain cDNA to elucidate the possible effects of UL141 on the nervous system. The findings of the current study demonstrate that the HCMV UL141 protein directly interacts with the human protein CUGBP Elav‑like family member 5 (CELF5) via yeast two‑hybrid screening, this interaction was confirmed by glutathione S‑transferase pull‑down and co‑immunoprecipitation assays. Additionally, the present study demonstrated that the UL141 protein co‑localizes with CELF5 in the cytoplasm of 293 cells using fluorescence confocal microscopy. CELF5 overexpression in a stably‑expressing cell line significantly increased viral DNA copy number and titer in HCMV‑infected U373MG cells. However, reducing CELF5 expression via specific small interfering RNAs did not affect viral DNA copy number or titer in HCMV‑infected cells. The current findings suggest that the interaction between UL141 and CELF5 may be involved in modulating viral DNA synthesis and progeny production. Therefore, CELF5 may represent a possible mechanism for regulation of HCMV genomic DNA synthesis, which is a key step during HCMV infection leading to neurological disease.

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.

Maternal immunoglobulin G avidity as a diagnostic tool to identify pregnant women at risk of congenital cytomegalovirus infection

BACKGROUND

The immunoglobulin (Ig) G avidity index (AI) is useful to detect primary cytomegalovirus (CMV) infection. However, because IgG matures with time, this index is not useful to detect a primary infection, unless measured at an appropriate time.

OBJECTIVES

We aimed to clarify the difference between using IgG AI and IgM positivity according to the stage of pregnancy to identify congenital CMV infection risk.

STUDY DESIGN

We collected the serum samples from 1115 pregnant women who underwent maternal screening for primary infection (n = 956) and were referred to our hospital because of CMV IgM positivity (n = 155) or had abnormal fetal ultrasonography findings (n = 4). The same sera samples were used to measure CMV IgM, IgG, and IgG AI. An IgG AI of <35% was defined as low. Neonatal urine collected within 5 days after birth was examined by polymerase chain reaction to confirm congenital infection.

RESULTS

Fourteen mothers gave birth to infected neonates. The sensitivity, specificity, and negative predictive values of the low IgG AI group with IgM-positive samples to discriminate between women with congenital infection at ≤14 weeks of gestation were 83.3, 83.8, and 99.1, respectively, which were higher than those of other subjects. Uni- and multivariate analyses revealed that IgM positivity and low IgG AI were independent variables associated with congenital infection at any stage of pregnancy, except low IgG AI at ≥15 weeks of gestation.

CONCLUSION

Low IgG AI with IgM positivity at ≤14 weeks of gestation was a good indicator of congenital infection, which should prove useful in obstetric practice.

Primary maternal cytomegalovirus infections: accuracy of fetal ultrasound for predicting sequelae in offspring

BACKGROUND

Cytomegalovirus infection is the most common perinatal viral infection that can lead to severe long-term medical conditions. Antenatal identification of maternal cytomegalovirus infections with proven fetal transmission and potential postnatal clinical sequelae remains a major challenge in perinatology. There is a need to improve the prenatal counseling offered to patients and guide future clinical management decisions in cases of proven primary cytomegalovirus infection.

OBJECTIVE

We sought to evaluate the accuracy of fetal ultrasound for predicting sequelae in fetuses infected with congenital cytomegalovirus after maternal primary infection.

STUDY DESIGN

We conducted a prospective observational study from 1996 through 2012 in pregnant women with serological evidence of primary cytomegalovirus infection and proven vertical transmission to the fetus, based on viral load in the amniotic fluid. Fetal ultrasound was performed in all patients. Pregnancy termination was presented as an option for infected fetuses. Hearing and neurological clinical assessments were performed for all neonates with cytomegalovirus-positive urine samples.

RESULTS

A total of 67 patients (69 fetuses) with proven vertical transmission were included in this study, including 64 singleton and 3 twin pregnancies. Eight fetuses were lost to follow-up. Of the remaining 61 fetuses, termination of the pregnancy was performed for 26, including 11 with fetal ultrasound anomalies. Autopsy provided histological evidence of fetal cytomegalovirus infection in all cases. In the 15 terminated fetuses without ultrasound anomalies, histological evidence of damage caused by fetal infection was detected in 13 cases. Among the 35 live-born infants, 12 had fetal ultrasound anomalies suggestive of congenital infection. Of these 12 infants, 6 had normal clinical evaluations, whereas 6 presented with either hearing and/or neurological anomalies, classified as severe in 4 cases. Among the 23 live-born infants with normal prenatal ultrasound, 5 developed hearing impairments and 1 showed mild neurological developmental delay.

CONCLUSION

Fetal ultrasound anomalies were detected in 37.7% of pregnant women with primary cytomegalovirus infection acquired in early pregnancy and proven fetal infection, and were confirmed by autopsy or postnatal clinical evaluation in 73.9%. Autopsy or postnatal clinical evaluation also detected cytomegalovirus-related anomalies in 55% of infants with normal fetal ultrasound evaluations.

Neutralizing and ELISA IgG antibodies to human cytomegalovirus glycoprotein complexes may help date the onset of primary infection in pregnancy

BACKGROUND

Definition of onset for primary human cytomegalovirus (HCMV) infection during pregnancy is critical for several reasons, including diagnosis of pre-conceptional infections and definition of gestational age at the time of infection.

OBJECTIVE

To determine the onset of primary HCMV infection, differential kinetics of antibodies neutralizing infection of epithelial and fibroblast cells, as well as ELISA IgG antibodies to HCMV glycoprotein complexes (gC) gH/gL/pUL128L, gH/gL/gO, and gB were exploited and compared with conventional assays.

STUDY DESIGN

In a series of 40 pregnant women with primary HCMV infection and ascertained HCMV-related mild clinical symptoms, the kinetics of different types of neutralizing and ELISA IgG antibodies were investigated with the aim of establishing criteria for dating the onset of primary infection in pregnant women without clinical symptoms.

RESULTS

IgG antibodies to gB and gH/gL/pUL128L, as well as antibodies neutralizing infection of epithelial cells appeared early after infection onset (within 2-3 weeks) and increased rapidly, whereas antibodies to gH/gL/gO and antibodies neutralizing infection of fibroblasts appeared later (>30 days) and increased slowly. Both the conventional diagnostic assays (IgG, and IgM antibody, and IgG avidity index) and the novel assays for determination of antibody responses directed against HCMV gC allowed the definition of an algorithm indicating the onset of primary HCMV infection in asymptomatic women within a period of 1-2 months.

CONCLUSION

New neutralization and ELISA IgG assays to HCMV gC provide additional tools for dating the onset of primary infection in pregnancy.