First-trimester diagnosis of congenital cytomegalovirus infection after maternal primary infection in early pregnancy: feasibility study of viral genome amplification by PCR on chorionic villi obtained by CVS.

OBJECTIVE: To evaluate the feasibility of amplification of the viral genome by polymerase chain reaction (PCR) analysis of trophoblast samples obtained by chorionic villus sampling (CVS) in cases of maternal primary infection (MPI) with cytomegalovirus (CMV) in early pregnancy. METHODS: This was a prospective study carried out at the Department of Obstetrics and Fetal Medicine, Hopital Necker-E.M., between October 2019 and October 2020. Following CMV serology screening in early pregnancy, CVS was offered to women at 11-14 weeks' gestation after CMV-MPI ≤ 10 weeks. Array-comparative genomic hybridization and amplification of the viral genome by PCR were performed on the trophoblasts obtained by CVS. All cases also underwent amniocentesis from 17 weeks onwards and PCR was performed on the amniotic fluid. Secondary prevention with valacyclovir was initiated as soon as MPI was diagnosed, to decrease the risk of vertical transmission. We evaluated the diagnostic performance of CMV-PCR of trophoblast obtained by CVS, using as the reference standard PCR of amniotic fluid obtained by amniocentesis. RESULTS: CVS was performed in 37 pregnancies, at a median (range) gestational age of 12.7 (11.3-14.4) weeks. CMV-PCR in chorionic villi was positive in three and negative in 34 cases. CMV-PCR following amniocentesis, performed at a median (range) gestational age of 17.6 (16.7-29.9) weeks, was positive for the three cases which were positive following CVS and, of the 34 patients with a negative finding following CVS, amniocentesis was negative in 31 and positive in three. The sensitivity of CMV-PCR analysis of trophoblast obtained by CVS for the diagnosis of CMV, using as the reference standard PCR analysis of amniotic fluid obtained by amniocentesis, was 50% (95% CI, 19-81%), specificity was 100% (95% CI, 89-100%), positive predictive value was 100% (95% CI, 44-100%) and negative predictive value was 91% (95% CI, 77-97%). CONCLUSIONS: Diagnosis of placental infection following MPI in early pregnancy can be achieved by PCR amplification of the CMV genome in chorionic villi. We propose that negative CMV-PCR in the trophoblast after 12 weeks could be used to exclude CMV-related embryopathy leading to sequelae. However, this needs to be confirmed through long-term follow-up evaluation. These findings could help to establish CVS as the diagnostic test of choice following maternal serology screening in early pregnancy. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Prenatal diagnosis of cerebral lesions acquired in utero and with a late appearance.

Although no precise figures are available, many congenital brain lesions arise from intrauterine disruption, frequently due to obstetric complications. The most common entities include intracranial hemorrhage, ischemic lesions, thrombosis of venous vessels and infections. Accurate prenatal diagnosis is possible in many of these cases. However, the findings may be subtle, particularly in the early stage of the disruptive process. Identification of these conditions requires therefore specific expertise, the combination of fetal neurosonography and magnetic resonance, and frequently there is a need for serial examinations. Targeted diagnostic imaging should be offered to obstetric patients with conditions predisposing to prenatal cerebral insults.

Secondary cytomegalovirus infection can cause severe fetal sequelae despite maternal preconceptional immunity.

OBJECTIVES: To describe our experience in cases with sonographic signs of fetal infection and with maternal serological 'immunity' to cytomegalovirus (CMV) infection. METHODS: This was a bicenter study of six pregnant women referred for evaluation of suspected fetal infection. All cases had confirmed maternal serology for past exposure to CMV but no evidence of recent secondary CMV infection. All underwent sonographic evaluation as well as complete investigation for CMV infection. RESULTS: The mean age of the women was 29 (range, 23-35) years and the mean gestational age at diagnosis was 23.5 weeks (range, 20-31) weeks. Sonographic findings included microcephaly, ventriculomegaly, periventricular calcifications and cystic lesions, echogenic bowel, hydrops and hepatosplenomegaly. Amniocentesis was performed in all cases for fetal karyotyping and viral assessment, and all were found by polymerase chain reaction to be positive for CMV infection. Four pregnancies were terminated following the parents' request. One pregnancy continued until intrauterine fetal death occurred 2 weeks after diagnosis. Postmortem was denied in all cases but one. One infant was delivered with evidence of severe cerebral palsy. CONCLUSION: In the presence of sonographic findings suggestive of fetal CMV infection, prompt investigation of amniotic fluid should follow even if maternal serology does not support recent maternal seroconversion.

No CMV DNA in Guthrie cards from children who later developed ALL.

An association of a viral infection in utero and development of acute lymphoblastic leukemia (ALL) has been suggested. Cytomegalovirus (CMV) has been reported as a leading agent of intrauterine infections resulting in some cases of congenital infections. The authors investigated the presence of prenatal CMV infection in children who later developed ALL. Guthrie cards were obtained from 48 children with ALL and 46 healthy children and were analyzed for the presence of CMV DNA by a real-time TaqMan PCR. CMV DNA was not detected in Guthrie cards from the children with ALL, from the control healthy children. The results show that prenatal CMV infection does not seem to be associated with later development of childhood ALL.

Neuropathogenesis induced by rhesus cytomegalovirus in fetal rhesus monkeys (Macaca mulatta).

Rhesus cytomegalovirus (RhCMV) infection of rhesus macaques offers opportunities to analyze mechanisms of CMV pathogenesis in a primate species. Four fetal rhesus monkeys were inoculated intraperitoneally with RhCMV early in the second trimester, and pregnancies were terminated by hysterotomy during the third trimester. Three fetuses had evidence of severe CMV disease, including intrauterine growth restriction, ventriculomegaly, microcephaly, lissencephaly, and extensive degenerative changes of the cerebral parenchyma. Histopathologic examination revealed polymicrogyria, gliosis, leptomeningitis, periventricular calcifications, and inclusion-bearing cells. These results demonstrate that the developing macaque brain is susceptible to infection with RhCMV early in the second trimester and that intrauterine infection results in neuropathologic outcomes similar to those observed in humans congenitally infected with CMV.

Congenital hepatic dysplasia from cytomegalovirus.

The Authors report on a case of liver dysplasia in a four-month-old infant affected by prenatal cytomegalovirus infection. Immunologic, histologic and ultrastructural studies suggest an embryopathic origin of the lesions.

Susceptibility of mouse embryo to murine cytomegalovirus infection in early and mid-gestation stages.

The susceptibility of mouse embryonic cells to murine cytomegalovirus (MCMV) infection was studied by injecting the virus in the early and mid-gestation stages. For the early stage, blastocysts from BDF1 mice were injected with MCMV or minimal essential medium (MEM) by micromanipulator and returned to the uteri of pseudopregnant ICR mice. On day 11 of gestation, the embryos were examined immunohistochemically, using antibody specific to the early antigen of MCMV, and the placentae were examined by plaque assay. No infection was detected by either method. Furthermore, no infection was detected in MCMV-infected blastocysts that were cultured and examined for infection by immunofluorescence. For mid-gestation embryos, the conceptus was injected with MCMV on day 8.5 of gestation and was subjected to immunohistochemical analysis from day 10.5 to 12.5 of gestation. Viral antigen-positive cells were first observed in the placentae, then antigen-positive cells appeared among the blood cells, endothelial and mesodermal cells of the embryos. On day 12.5 of gestation, clusters of viral antigen-positive cells were sometimes observed in the hearts and livers. Although the incidence was lower, viral antigen-positive cells were also observed in the neuroectoderm and the eyes. These results suggest that MCMV does not infect early embryos and that infection first occurs in the placenta of postimplantation embryos, whence it extends through the blood cells to the endothelial and mesodermal cells of different embryonic regions, eventually extending to the neuroectoderm.

Lethal cytomegalovirus infection in preterm infants: clinical, radiological, and neuropathological findings.

Fifteen premature infants with lethal congenital cytomegalovirus infection were studied to determine the clinical, neuroradiological, and neuropathological characteristics of the disease in this population. Nine infants were liveborn but died at a postnatal age of 18 +/- 21 days; 6 infants were stillborn. Clinical findings in liveborn infants included microcephaly (77%), seizures (55%), hypotonia (33%), and multiple contractures (18%). Ophthalmological findings included chorioretinitis, optic atrophy, and corneal opacities. Neuroradiological findings included the postnatal evolution of periventricular calcification in 1 infant, and cerebellar hypoplasia diagnosed by magnetic resonance imaging in 1 infant. Neuropathological findings included periventricular necrosis and calcification (12), associated diffuse calcification frequently involving the convexity of the gyri (6), cerebellar hypoplasia (5), periventricular leukomalacia (2), intraventricular hemorrhage (2), hydrocephalus (2), and porencephalic cyst (1). Intranuclear inclusion bodies within the brain were observed in 4 infants, whereas systemic inclusion bodies were present in all infants. These data indicate several atypical findings in preterm infants rarely reported in term infants, including hypotonia, multiple contractures, periventricular leukomalacia, and optic atrophy.

Early-stage developmental abnormalities induced by murine cytomegalovirus.

The onset of the effects of murine cytomegalovirus (MCMV) infection on an early stage of embryonic development (nine days) in a mouse model was studied with the aid of scanning electron microscopy. MCMV was injected into the endometrial lumina of pregnant mice at the time of implantation. The mice were later killed, and sites of embryonic implantation were examined. Compared with uninfected mice and mice inoculated with heat-inactivated virus, litter sizes were reduced, and the incidence of abnormal fetuses was significantly increased among MCMV-infected animals. Scanning electron microscopy also revealed maldeveloped cranial regions characterized by an unclosed neural tube and severely underdeveloped head. Ectodermal abnormalities, including poxlike formations and ballooning cells, were observed in several embryos. Thus, early cytomegalovirus infection may not only result in fetal loss, but may also interfere with the process of morphogenesis.