[Genetic polymorphism of cytomegalovirus strains responsible of congenital infections]

Cytomegalovirus Genetic Diversity and Evolution: Insights into Genotypes and Their Role in Viral Pathogenesis

Cytomegalovirus (CMV) is a ubiquitous virus that infects most of the human population and causes significant morbidity and mortality, particularly among immunocompromised individuals. Understanding CMV's genetic diversity and evolutionary dynamics is crucial for elucidating its pathogenesis and developing effective therapeutic interventions. This review provides a comprehensive examination of CMV's genetic diversity and evolution, focussing on the role of different genotypes in viral pathogenesis.

Quantitative and qualitative analysis of fetal temporal lobe T2 signal in cytomegalovirus infected fetuses and normal controls

Background

Temporal lobe T2 hyperintensity has been described in association with prenatal cytomegalovirus (CMV) infection on fetal MRI. However, these findings are often perplexing with high inter-observer variability. Our objective was to evaluate temporal lobe T2 signal quantitatively in prenatal CMV infection.

Methods

In this retrospective study, 119 fetuses, of which 51 fetuses with suspected CMV exposure (29-36 weeks of gestation) based on maternal seroconversion and age-matched 68 normal controls, were included. Mean and maximal temporal lobe T2 signal were evaluated quantitatively by measuring the T2 signal in the temporal lobes relative to the amniotic fluid's signal. Intra-observer, inter-observer variability and diagnostic performance were assessed. The occurrence of neonatal sensorineural hearing loss (SNHL) was recorded.

Results

Relative temporal lobe T2 signal did not change along with the examined gestational age. Of our suspected CMV cohort, 29 fetuses were positive for fetal CMV infection on polymerase chain reaction (PCR) analysis. There were no statistically significant differences in the relative mean or maximal temporal lobes T2 signal between CMV positive, CMV negative fetuses, or normal controls. No correlation was found between neonatal SNHL and temporal lobe T2 signal.

Conclusions

When temporal lobe T2 signal is analyzed quantitatively, CMV infected fetuses do not present an increased signal than age-matched controls. Thus, reported subjective temporal T2 hyperintensities should be interpreted carefully and should have a limited effect on pregnancy management, especially as an isolated finding. Our study illustrates the importance of quantitative imaging in diagnostic neuroradiology.

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.

The myeloid transcription factor GATA-2 regulates the viral UL144 gene during human cytomegalovirus latency in an isolate-specific manner

It is generally accepted that, following primary infection, human cytomegalovirus (HCMV) establishes lifelong latency in CD34(+) progenitor cells and other derivative cells of the myeloid lineage. In this study, we show that the viral UL144 gene is expressed during latent infection in two cell types of the myeloid lineage, CD34(+) and CD14(+) monocytes, and that the UL144 protein is functional in latently infected monocytes. However, this latency-associated expression of UL144 occurs only in certain isolates of HCMV and depends on the presence of functional GATA-2 transcription factor binding sites in the UL144 promoter, in contrast to the viral latency-associated gene LUNA, which we also show is regulated by GATA-2 but expressed uniformly during latent infection independent of the virus isolate. Taken together, these data suggest that the HCMV latency-associated transcriptome may be virus isolate specific and dependent on the repertoire of transcription factor binding sites in the promoters of latency-associated genes.