Diagnosis and prognosis of congenital CMV infection: a case report and review of the literature

Diagnosing congenital cytomegalovirus infections using archived dried blood spots: A 15-year observational study, Portugal

BACKGROUND

Cytomegalovirus (CMV) is a leading cause of congenital infections. Dried blood spots (DBS) collected in the first week of life (Guthrie cards) have been used in the diagnosis of CMV infection outside the three-week window period following birth. The present work summarizes the results of a 15-year observational study in which DBS from 1388 children were used for a late diagnosis of congenital CMV infection.

METHODS

Three groups of children were studied: (i) symptomatic (with symptoms at birth or late sequelae) (N = 779); (ii) born to mothers with serological profile of primary CMV infection (N = 75); (iii) without any information (N = 534). A highly sensitive method of DNA extraction (heat-induced) from the DBS was used. CMV DNA was detected by a nested PCR.

RESULTS

In total CMV DNA was detected in 7.5% (104/1388) of children. Symptomatic children showed a low rate of CMV DNA detection (6.7%) than children born to mothers with serological profile of primary CMV infection (13.3%) (p = 0.034). Sensorial hearing loss and encephalopathy were the two clinical manifestations with the highest CMV detection rate (18.3% and 11.1%, respectively). Children whose mothers had a confirmed primary infection showed a higher rate of CMV detection (35.3%) when compared with children whose mothers had a not confirmed primary infection (6.9%) (p = 0.007).

CONCLUSION

The present work emphasises the importance of testing DBS in symptomatic children even a long time after symptoms onset and in children born to mothers with serologic diagnosis of maternal primary CMV infection when they miss the diagnosis during the three-week window following birth.

Fetal Brain Damage in Human Fetuses with Congenital Cytomegalovirus Infection: Histological Features and Viral Tropism

Human cytomegalovirus (HCMV) causes congenital neurological lifelong disabilities. To date, the neuropathogenesis of brain injury related to congenital HCMV (cCMV) infection is poorly understood. This study evaluates the characteristics and pathogenetic mechanisms of encephalic damage in cCMV infection. Ten HCMV-infected human fetuses at 21 weeks of gestation were examined. Specifically, tissues from different brain areas were analyzed by: (i) immunohistochemistry (IHC) to detect HCMV-infected cell distribution, (ii) hematoxylin-eosin staining to evaluate histological damage and (iii) real-time PCR to quantify tissue viral load (HCMV-DNA). The differentiation stage of HCMV-infected neural/neuronal cells was assessed by double IHC to detect simultaneously HCMV-antigens and neural/neuronal markers: nestin (a marker of neural stem/progenitor cells), doublecortin (DCX, marker of cells committed to the neuronal lineage) and neuronal nuclei (NeuN, identifying mature neurons). HCMV-positive cells and viral DNA were found in the brain of 8/10 (80%) fetuses. For these cases, brain damage was classified as mild (n = 4, 50%), moderate (n = 3, 37.5%) and severe (n = 1, 12.5%) based on presence and frequency of pathological findings (necrosis, microglial nodules, microglial activation, astrocytosis, and vascular changes). The highest median HCMV-DNA level was found in the hippocampus (212 copies/5 ng of human DNA [hDNA], range: 10-7,505) as well as the highest mean HCMV-infected cell value (2.9 cells, range: 0-23), followed by that detected in subventricular zone (1.7 cells, range: 0-19). These findings suggested a preferential viral tropism for both neural stem/progenitor cells and neuronal committed cells, residing in these regions, confirmed by the expression of DCX and nestin in 94% and 63.3% of HCMV-positive cells, respectively. NeuN was not found among HCMV-positive cells and was nearly absent in the brain with severe damage, suggesting HCMV does not infect mature neurons and immature neural/neuronal cells do not differentiate into neurons. This could lead to known structural and functional brain defects from cCMV infection.

Ultrasound Findings of Fetal Infections: Current Knowledge

Infectious diseases during pregnancy are still a major cause of fetal mortality and morbidity worldwide. The most common teratogenic pathogens are cytomegalovirus (CMV), varicella-zoster virus (VZV), rubeovirus, parvovirus B19, herpes simplex virus (HSV), Toxoplasma gondii, Treponema pallidum and the emergent Zika virus (ZIKV). Ultrasound findings include cerebral anomalies, orbital defects, micrognathia, cardiac defects, hepatosplenomegaly, liver calcifications, abdominal anomalies, skin and limb anomalies, edema, placental and amniotic fluid anomalies and altered Doppler analyses. The classification of ultrasound markers of congenital infections by anatomical region is reported to guide differential diagnosis and prenatal care.

Universal Newborn Screening for Congenital Cytomegalovirus Infection - From Infant to Maternal Infection: A Prospective Multicenter Study

INTRODUCTION

Most infants at risk for cytomegalovirus (CMV)-associated sensorineural hearing loss (SNHL) are unrecognized because of the absence of a universal neonatal CMV screening. The search of CMV-DNA by molecular methods in salivary swabs was demonstrated to be a reliable approach. This study describes the results obtained by carrying out a universal screening for congenital CMV (cCMV) infection including all live-born newborns in three Italian sites, as well as the therapeutic interventions and clinical outcome of the CMV-infected neonates. Moreover, CMV maternal infection's characteristics were evaluated.

METHODS

To confirm or exclude cCMV infection, a CMV-DNA-positive result on a first salivary swab was followed by repeated saliva and urine samples collected within 21 days of age. Breast milk samples were also collected. The search of CMV-DNA was performed with a single automated quantitative commercial real-time PCR assay, regardless of the type of samples used.

RESULTS

A total of 3,151 newborns were enrolled; 21 (0.66%) of them were congenitally infected (median saliva viral load at screening, 6.65 [range, 5.03-7.17] log₁₀ IU/ml). Very low/low viral load in screening saliva samples (median value, 1.87 [range, 1.14-2.59] log₁₀ IU/ml) was associated with false-positive results (n = 54; 1.7%). CMV-DNA was detected in almost half of the breast milk samples of mother-infant pairs with a false-positive result, suggesting that contamination from breast milk may not be the only explanation in the study population. cCMV infection confirmation with the search of CMV-DNA in a urine sample proved to be the gold standard strategy, since false-positive results were observed in 4/54 (7.5%) of the repeated saliva samples. Symptomatic cCMV infection was observed in 3/21 (14.3%) infants; notably, one (4.7%) developed moderate unilateral SNHL at 5 months after birth. Finally, two symptomatic cCMV infections were associated with primary maternal infection acquired in the first trimester of gestation; one newborn with severe cCMV symptoms was born to a mother with no CMV checkups in pregnancy.

CONCLUSION

Without universal neonatal CMV screening, some infected infants who develop late neurological sequelae may not be recognized and, consequently, they are not able to benefit early from instrumental and therapeutic interventions to limit and/or treat CMV disease.

Immune Monitoring Using QuantiFERON®-CMV Assay in Congenital Cytomegalovirus Infection: Correlation With Clinical Presentation and CMV DNA Load

BACKGROUND

Cytomegalovirus (CMV)-specific CD8 + T-cell responses can be detected early in fetal life, but their role in the manifestations of congenital CMV (cCMV) infection remains largely unknown.

METHODS

CMV-specific CD8 + T-cell responses were assessed in neonates with cCMV using QuantiFERON®-CMV assay, within day 14 of life (T0) and during the second month of life (T1). Detection and quantification of CMV DNA in whole blood and urine samples were performed at both time points. QuantiFERON®-CMV results were evaluated in relation to timing of maternal infection, clinical manifestations of cCMV and CMV DNA levels.

RESULTS

Thirty neonates were enrolled (10/30 [33%] symptomatic; 20/30 [67%] asymptomatic). At T0 16/30 (53%) subjects had a reactive QuantiFERON®-CMV result and 16/16 (100%) were asymptomatic, whereas 14/30 (47%) had a nonreactive or indeterminate QuantiFERON®-CMV result and 4/14 (29%) were asymptomatic. At T1, 17/29 (59%) subjects had a reactive QuantiFERON®-CMV result, and 17/17 (100%) were asymptomatic, whereas 12/29 (41%) had a nonreactive or indeterminate result and 3/12 (25%) were asymptomatic. At both T0 and T1 reactive QuantiFERON®-CMV results correlated with lack of symptoms (P = .0001). At T1 median CMV DNAemia was lower in subjects with reactive QuantiFERON®-CMV results as compared with subjects with nonreactive or indeterminate results (1.82 log IU/mL [1.82-2.89] vs 2.55 log IU/mL [1.82-4.42], P = .009). No correlation was found between QuantiFERON®-CMV results and gestational age at maternal infection nor with urine CMV DNA levels.

CONCLUSIONS

A detectable CMV-specific CD8 + T-cell response, evaluated using the QuantiFERON®-CMV assay, correlates with the lack of CMV-related symptoms and the control of CMV DNAemia.

CMV-Specific Cell-Mediated Immunity in Immunocompetent Adults with Primary CMV Infection: A Case Series and Review of the Literature

Cytomegalovirus-specific cell-mediated immunity (CMV-CMI) in actively infected healthy immunocompetent hosts has been poorly investigated. Conversely, correlates of maternal protective immunity for the fetus after primary infection in pregnancy continue to be studied. The kinetics and magnitude of CMV-specific CMI in immunocompetent primary CMV-infected adults are described. A literature review on CMV-CMI in primarily infected pregnant women and its correlation to the risk of vertical virus transmission is included. Immunological measurements after infection were performed by enzyme-linked ImmunoSPOT assay enumerating IFN-γ secreting CMV-specific T cells, at a single cell level, upon in vitro stimulation with viral antigens. Simultaneously, serological and virological profiles of infected patients were investigated. Patients displayed mild-to-moderate clinical and laboratory profiles for infection, and all showed positive EliSpot results in the early stage of infection (<20 days after onset). The virus-CMI was strong in the majority of patients (58.8%) in which the lowest CMV-DNAemia levels (<300 copies/mL) were detected. Significantly higher viral loads were observed in patients with weak CMV-CMI at the same time-point post-infection (up to 15,104 copies/mL; p < 0.001). T cell response magnitudes to IE-1 and pp65-UL83 peptides were overlapping and stable over time. In these case series, the early presence of CMV-CMI was probably pivotal in controlling viral replication and led to spontaneous viral clearance.

Placental Cytomegalovirus Infection

In the United States, cytomegalovirus is the most common congenital viral infection and the number 1 cause of nonhereditary sensorineural hearing loss. The vast majority of infants may be asymptomatic, especially if cytomegalovirus is contracted later in the pregnancy, and some symptoms may have a delayed onset. Therefore, it is important for the pathologist to identify the common histologic findings to help confirm the diagnosis so the child can be followed for late sequelae. Histologic examination of the placenta is important in live births and in cases of intrauterine fetal demise. Chronic lymphoplasmacytic villitis and fibrotic, avascular villi are the most common findings. When present, Cowdry A intranuclear and basophilic intracytoplasmic inclusions are characteristic. Immunohistochemistry for cytomegalovirus can highlight these inclusions as well as the associated eosinophilic debris. In addition, polymerase chain reaction or viral culture on placental or fetal samples can be performed for confirmation.

Cytomegalovirus establishes a latent reservoir and triggers long-lasting inflammation in the eye

Recent outbreaks of Ebola and Zika have highlighted the possibility that viruses may cause enduring infections in tissues like the eye, including the neural retina, which have been considered immune privileged. Whether this is a peculiarity of exotic viruses remains unclear, since the impact of more common viral infections on neural compartments has not been examined, especially in immunocompetent hosts. Cytomegalovirus is a common, universally distributed pathogen, generally innocuous in healthy individuals. Whether in immunocompetent hosts cytomegalovirus can access the eye, and reside there indefinitely, was unknown. Using the well-established murine cytomegalovirus infection model, we show that systemic infection of immunocompetent hosts results in broad ocular infection, chronic inflammation and establishment of a latent viral pool in the eye. Infection leads to infiltration and accumulation of anti-viral CD8+ T cells in the eye, and to the development of tissue resident memory T cells that localize to the eye, including the retina. These findings identify the eye as an unexpected reservoir for cytomegalovirus, and suggest that common viruses may target this organ more frequently than appreciated. Notably, they also highlight that infection triggers sustained inflammatory responses in the eye, including the neural retina.

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.

Congenital Cytomegalovirus Infection: Prognostic Value of Maternal DNAemia at Amniocentesis

BACKGROUND

Human Cytomegalovirus (HCMV) is the most common cause of childhood hearing loss and can lead to neurodevelopmental delay. To date, few studies have examined the correlation between maternal viremia and congenital HCMV infection. The aim of our study was to ascertain if HCMV DNA in the peripheral blood of pregnant women with primary HCMV infection at the time of amniocentesis may have a prognostic value in terms of congenital infection and neonatal symptomatic disease.

METHODS

We performed a prospective observational study of pregnant women referred to our maternal-fetal medicine division with suspected HCMV infection. Primary infection was diagnosed based on seroconversion for HCMV and/or HCMV immunoglobulin M-positive and low or moderate HCMV immunoglobulin G avidity. At the time of amniocentesis, maternal blood samples were collected and analyzed by means of real-time polymerase chain reaction to determine the presence of viral DNAemia. Fetuses and newborns were evaluated for the presence of congenital infection and symptomatic disease.

RESULTS

A total of 239 pregnant women were enrolled; 32 blood samples (13.4%) were positive, and 207 (86.6%) were negative for HCMV DNA. The overall rate of transmission was 23.4%. Fifteen infected patients (26.8%) were symptomatic. Vertical transmission occurred in 14 women (43.8%) with positive and 42 (20.3%) with negative results for HCMV DNAemia (P = .006; odds ratio, 3.06; 95% confidence interval, 1.41-6.64). Symptomatic infection occurred in 6 (42.9%) infected fetuses or newborns from women with and in 9 (21.4%) from women without viral DNAemia (P = .16).

CONCLUSION

Maternal viremia at amniocentesis is associated with a 3-fold greater chance of congenital infection, but it is not correlated with symptomatic disease.

Pattern of circulation of MCMV mimicking natural infection upon oronasal inoculation

Cytomegaloviruses may infect mammals via oronasal route. However, up till now it remains unclear how this exposure leads to a general infection and shedding. To address this issue, BALB/c female mice were oronasally inoculated with either the highly passaged murine cytomegalovirus (MCMV) Smith or the low passaged MCMV HaNa1. Virus titration showed a productive virus replication of both strains in the nasal mucosa from 1 dpi until the end of the experiment (14 dpi), in lungs from 5 until 14 dpi, and in submandibular glands from 7 until 14 dpi. In contrast to MCMV HaNa1, MCMV Smith also established a low level productive infection in abdominal organs (spleen, liver and kidneys) from 5 dpi (spleen), 7 dpi (liver), and 10 dpi (kidneys) until the end of the experiment. Co-culture showed that for both strains, cell-associated virus was detected in a non-infectious form in nasopharynx-associated lymphoid tissues (NALT) from 1 until 14 dpi, in submandibular lymph nodes from 3 until 5 dpi, in deep cervical lymph nodes from 3 until 14 dpi, in mediastinal lymph nodes from 7 until 14 dpi, in spleen from 5 until at least 10 dpi and in the peripheral blood mononuclear cells (PBMC) at 7 and 10 dpi. The present study shows that upon oronasal exposure, MCMV first enters the nasal mucosa and NALT, from where the virus disseminates to the spleen possibly via the draining lymphatic system and blood; a subsequent cell-associated viremia transports MCMV to submandibular glands and for MCMV Smith also to liver and kidneys, where a second productive replication starts.

Vaccine-Derived Neutralizing Antibodies to the Human Cytomegalovirus gH/gL Pentamer Potently Block Primary Cytotrophoblast Infection

Human cytomegalovirus (HCMV) elicits neutralizing antibodies (NAb) of various potencies and cell type specificities to prevent HCMV entry into fibroblasts (FB) and epithelial/endothelial cells (EpC/EnC). NAb targeting the major essential envelope glycoprotein complexes gB and gH/gL inhibit both FB and EpC/EnC entry. In contrast to FB infection, HCMV entry into EpC/EnC is additionally blocked by extremely potent NAb to conformational epitopes of the gH/gL/UL128/130/131A pentamer complex (PC). We recently developed a vaccine concept based on coexpression of all five PC subunits by a single modified vaccinia virus Ankara (MVA) vector, termed MVA-PC. Vaccination of mice and rhesus macaques with MVA-PC resulted in a high titer and sustained NAb that blocked EpC/EnC infection and lower-titer NAb that inhibited FB entry. However, antibody function responsible for the neutralizing activity induced by the MVA-PC vaccine is uncharacterized. Here, we demonstrate that MVA-PC elicits NAb with cell type-specific neutralization potency and antigen recognition pattern similar to human NAb targeting conformational and linear epitopes of the UL128/130/131A subunits or gH. In addition, we show that the vaccine-derived PC-specific NAb are significantly more potent than the anti-gH NAb to prevent HCMV spread in EpC and infection of human placental cytotrophoblasts, cell types thought to be of critical importance for HCMV transmission to the fetus. These findings further validate MVA-PC as a clinical vaccine candidate to elicit NAb that resembles those induced during HCMV infection and provide valuable insights into the potency of PC-specific NAb to interfere with HCMV cell-associated spread and infection of key placental cells.

IMPORTANCE

As a consequence of the leading role of human cytomegalovirus (HCMV) in causing permanent birth defects, developing a vaccine against HCMV has been assigned a major public health priority. We have recently introduced a vaccine strategy based on a widely used, safe, and well-characterized poxvirus vector platform to elicit potent and durable neutralizing antibody (NAb) responses targeting the HCMV envelope pentamer complex (PC), which has been suggested as a critical component for a vaccine to prevent congenital HCMV infection. With this work, we confirm that the NAb elicited by the vaccine vector have properties that are similar to those of human NAb isolated from individuals chronically infected with HCMV. In addition, we show that PC-specific NAb have potent ability to prevent infection of key placental cells that HCMV utilizes to cross the fetal-maternal interface, suggesting that NAb targeting the PC may be essential to prevent HCMV vertical transmission.

Congenital cytomegalovirus infections and glycoprotein B genotypes in live-born infants: a prevalence study in Turkey

BACKGROUND

Cytomegalovirus (CMV) infections are the leading cause of infectious hearing loss and central nervous system disease among children worldwide. In this study, we aimed to determine the birth prevalence of congenital CMV infection in live-born infants in Turkey.

METHODS

In total, 944 consecutive live-born infants born from 926 pregnant women were included in this study. CMV-DNA was investigated in saliva samples of all newborns within the first 3 days after birth using TaqMan-based real-time PCR.

RESULTS

The birth prevalence of congenital CMV infection in live-born infants was 1.91% (18/944), and all congenitally infected infants were asymptomatic at birth. The prevalence of congenital CMV infection was 16.7% (3/18) in twin pregnancies and 1.32% (12/908) in single pregnancies (p = 0.002). Genotyping analysis showed glycoprotein B-1 (gB1) to be the most frequently detected genotype at 83.3%.

CONCLUSION

The study results suggest that the majority of congenital CMV infection in Turkey occurs following nonprimary maternal infection. We believe that congenital CMV infection and its long-term effects have been underestimated in our country, as infected infants are usually asymptomatic at birth.