Etiology of severe sensorineural hearing loss in children: independent impact of congenital cytomegalovirus infection and GJB2 mutations

Analysis of Suspected Measles Cases with Discrepant Measles-Specific IgM and rRT-PCR Test Results, Japan

We investigated clinically suspected measles cases that had discrepant real-time reverse transcription PCR (rRT-PCR) and measles-specific IgM test results to determine diagnoses. We performed rRT-PCR and measles-specific IgM testing on samples from 541 suspected measles cases. Of the 24 IgM-positive and rRT-PCR--negative cases, 20 were among children who received a measles-containing vaccine within the previous 6 months; most had low IgG relative avidity indexes (RAIs). The other 4 cases were among adults who had an unknown previous measles history, unknown vaccination status, and high RAIs. We detected viral nucleic acid for viruses other than measles in 15 (62.5%) of the 24 cases with discrepant rRT-PCR and IgM test results. Measles vaccination, measles history, and contact history should be considered in suspected measles cases with discrepant rRT-PCR and IgM test results. If in doubt, measles IgG avidity and PCR testing for other febrile exanthematous viruses can help confirm or refute the diagnosis.

Antiviral Treatment of Maternal and Congenital Cytomegalovirus (CMV) Infections

Human Cytomegalovirus (HCMV) is a ubiquitous member of the Herpesviridae family, responsible for the most common congenital viral infection-congenital Cytomegalovirus (cCMV) infection. While a majority of HCMV infections in children and adults are asymptomatic, HCMV is well known to cause severe infections in the immunocompromised individual and maternal infections with variable long-term sequelae after maternal-fetal transmission with primary or nonprimary infections. HCMV seroprevalence and cCMV incidence vary by geographic area and demographic characteristics like race and socioeconomic status. While cCMV birth prevalence ranges from 0.2% to 6% in different parts of the world, it is influenced by regional HCMV seroprevalence rates. HCMV screening during pregnancy is not routinely offered due to lack of awareness, hurdles to accurate diagnosis, and lack of well-established effective treatment options during pregnancy. This review will focus on antiviral treatment options currently available for use during pregnancy and in the newborn period for the treatment of maternal and congenital HCMV infections.

Characterization of epitopes of human monoclonal antibodies against cytomegalovirus glycoprotein B for neutralization and antibody-dependent phagocytosis

As congenital cytomegalovirus (CMV) infections are the leading non-genetic cause of sensorineural hearing loss and significant neurological disabilities in children, the development of CMV vaccines should be given the highest public health priority. Although MF59-adjuvanted glycoprotein B (gB) vaccine (gB/MF59) is safe and immunogenic, its efficacy in terms of protection from natural infection was around 50 % in clinical trials. Although gB/MF59 induced high antibody titers, anti-gB antibodies contributed little to the neutralization of infection. Recent studies have found that non-neutralizing functions, including antibody-dependent phagocytosis of virions and virus-infected cells, are likely to play important roles in pathogenesis and vaccine design. Previously, we isolated human monoclonal antibodies (MAbs) that reacted with the trimeric form of gB ectodomain and found that preferential epitopes for neutralization were present on Domains (Doms) I and II of gB, while there were abundant non-neutralizing antibodies targeting Dom IV. In this study, we analyzed the phagocytosis activities of these MAbs and found the following: 1) MAbs effective for phagocytosis of the virions targeted Doms I and II, 2) the MAbs effective for phagocytosis of the virions and those of virus-infected cells were generally distinct, and 3) the antibody-dependent phagocytosis showed little correlation with neutralizing activities. Taking account of the frequency and levels of neutralization and phagocytosis, incorporation of the epitopes on Doms I and II into developing vaccines is considered desirable for the prevention of viremia.

Vestibular Deficits in Deafness: Clinical Presentation, Animal Modeling, and Treatment Solutions

The inner ear is responsible for both hearing and balance. These functions are dependent on the correct functioning of mechanosensitive hair cells, which convert sound- and motion-induced stimuli into electrical signals conveyed to the brain. During evolution of the inner ear, the major changes occurred in the hearing organ, whereas the structure of the vestibular organs remained constant in all vertebrates over the same period. Vestibular deficits are highly prevalent in humans, due to multiple intersecting causes: genetics, environmental factors, ototoxic drugs, infections and aging. Studies of deafness genes associated with balance deficits and their corresponding animal models have shed light on the development and function of these two sensory systems. Bilateral vestibular deficits often impair individual postural control, gaze stabilization, locomotion and spatial orientation. The resulting dizziness, vertigo, and/or falls (frequent in elderly populations) greatly affect patient quality of life. In the absence of treatment, prosthetic devices, such as vestibular implants, providing information about the direction, amplitude and velocity of body movements, are being developed and have given promising results in animal models and humans. Novel methods and techniques have led to major progress in gene therapies targeting the inner ear (gene supplementation and gene editing), 3D inner ear organoids and reprograming protocols for generating hair cell-like cells. These rapid advances in multiscale approaches covering basic research, clinical diagnostics and therapies are fostering interdisciplinary research to develop personalized treatments for vestibular disorders.

Selective Inner Hair Cell Loss in a Neonate Harbor Seal (Phoca vitulina)

Simple Summary

Congenital hearing loss (i.e., hearing impairment present at birth) is recognized in humans and other terrestrial species, but there is a lack of information on congenital malformations and associated hearing loss in pinnipeds (seals, sea lions, and walruses). Baseline knowledge on marine mammal inner ear malformations is essential to differentiate between congenital and acquired abnormalities, which may be caused by infectious agents, age, or anthropogenic interactions, such as noise exposure. Analysis of the cochlea of a neonate harbor seal (Phoca vitulina) revealed bilateral loss of inner hair cells (sensory cells responsible for transducing the auditory signal) while the outer hair cells (sensory cells responsible for sound amplification and frequency selectivity and sensitivity) were intact. The selective inner hair cell loss (up to 84.6% of loss) was more severe in the basal turn, where the high frequencies are encoded. Potential causes and consequences are discussed. This is the first report of a case of selective inner hair cell loss in a marine mammal neonate, likely congenital.

Abstract

Congenital hearing loss is recognized in humans and other terrestrial species. However, there is a lack of information on its prevalence or pathophysiology in pinnipeds. It is important to have baseline knowledge on marine mammal malformations in the inner ear, to differentiate between congenital and acquired abnormalities, which may be caused by infectious pathogens, age, or anthropogenic interactions, such as noise exposure. Ultrastructural evaluation of the cochlea of a neonate harbor seal (Phoca vitulina) by scanning electron microscopy revealed bilateral loss of inner hair cells with intact outer hair cells. The selective inner hair cell loss was more severe in the basal turn, where high-frequency sounds are encoded. The loss of inner hair cells started around 40% away from the apex or tip of the spiral, reaching a maximum loss of 84.6% of hair cells at 80–85% of the length from the apex. Potential etiologies and consequences are discussed. This is believed to be the first case report of selective inner hair cell loss in a marine mammal neonate, likely congenital.

Cytomegalovirus-A Risk Factor for Childhood Hearing Loss: A Systematic Review

OBJECTIVE

Permanent hearing loss is an important public health issue in children with consequences for language, social, and academic functioning. Early hearing detection, intervention, and monitoring are important in mitigating the impact of permanent childhood hearing loss. Congenital cytomegalovirus (CMV) infection is a leading cause of hearing loss. The purpose of this review was to synthesize the evidence on the association between CMV infection and permanent childhood hearing loss.

DESIGN

We performed a systematic review and examined scientific literature from the following databases: MEDLINE, Ovid MEDLINE(R) Daily and Ovid MEDLINE(R), Embase, and CINAHL. The primary outcome was permanent bilateral or unilateral hearing loss with congenital onset or onset during childhood (birth to 18 years). The secondary outcome was progressive hearing loss. We included studies reporting data on CMV infection. Randomized controlled trials, quasi-experimental studies, nonrandomized comparative and noncomparative studies, and case series were considered. Data were extracted and the quality of individual studies was assessed with the Qualitative Assessment Tool for Quantitative Studies (McMaster University). The quality and strength of the evidence were graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE). A narrative synthesis was completed.

RESULTS

Sixty-five articles were included in the review. Prevalence of hearing loss at birth was over 33% among symptomatic CMV-infected newborns and less than 15% in asymptomatic infections. This difference in prevalence was maintained during childhood with more than 40% prevalence reported for symptomatic and less than 30% for asymptomatic CMV. Late-onset and progressive hearing loss appear to be characteristic of congenital CMV infections. Definitions of hearing loss, degree of loss, and reporting of laterality varied across studies. All degrees and both bilateral and unilateral loss were reported, regardless of symptomatic and asymptomatic status at birth, and no conclusions about the characteristics of hearing loss could be drawn. Various patterns of hearing loss were reported including stable, progressive, and fluctuating, and improvement in hearing (sometimes to normal hearing) was documented. These changes were reported in children with symptomatic/asymptomatic congenital CMV infection, presenting with congenital/early onset/late-onset hearing loss and in children treated and untreated with antiviral medication.

CONCLUSIONS

Symptomatic and asymptomatic congenital CMV infection should be considered a risk factor for hearing loss at birth and during childhood and for progressive hearing loss. Therefore, CMV should be included as a risk factor in screening and surveillance programs and be taken into account in clinical follow-up of children with hearing loss.

Cytomegalovirus infections in pregnant women as a risk of congenital deafness in a child

Introduction

One per cent of live births are affected by cytomegalovirus infection, but 90% of neonates with perinatal infection do not show symptoms of disease. Symptomatic cytomegalovirus (CMV) is present in 5-10% of children. Typical clinical signs of congenital cytomegalovirus infection are microcephalia, mental retardation, progressive major amblyacousia, and neuromuscular infection. Hypoacusis is present in 30-60% of children with congenital symptomatic CMV - in most cases it is bilateral and applies to high-frequency hearing loss.

Material and methods

A group of 70 children had serological and genetic screening of viral DNA using the polymerase chain reaction method in urine and blood. In this group, 52 children were diagnosed with congenital CMV, and 10 children were diagnosed with acquired CMV. Audiological examinations including pure-tone audiometry, auditory brainstem response, transiently evoked otoacoustic emission, and immittance audiometry were performed.

Results

Bilateral sensorineural hearing loss was in 9 children associated with mental and physical retardation, brain malformation, and microcephalia. Unilateral hearing loss was observed in 3 children. In 40 cases, we did not observe hearing loss, although the level of bilirubin was high, as well as splenomegaly, hepatomegaly, and facial nerve paralysis.

Conclusions

Congenital cytomegalovirus infection often caused hearing loss. Children with congenital and acquired CMV should be under the permanent care of an audiologist. The growing problem of CMV infections and their late diagnosis suggests the need to prepare screening tests and increase the education of gynaecologists, neonatologists, paediatricians, and general practice doctors about CMV problems.

Clinical Diagnostic Testing for Human Cytomegalovirus Infections

Human cytomegalovirus (HCMV) infections are among the most common complications arising in transplant patients, elevating the risk of various complications including loss of graft and death. HCMV infections are also responsible for more congenital infections worldwide than any other agent. Congenital HCMV (cCMV) infections are the leading nongenetic cause of sensorineural hearing loss and a source of significant neurological disabilities in children. While there is overlap in the clinical and laboratory approaches to diagnosis of HCMV infections in these settings, the management, follow-up, treatment, and diagnostic strategies differ considerably. As yet, no country has implemented a universal screening program for cCMV. Here, we summarize the issues, limitations, and application of diagnostic strategies for transplant recipients and congenital infection, including examples of screening programs for congenital HCMV that have been implemented at several centers in Japan, Italy, and the United States.

Identification and functional analyses of a cell-death inhibitor encoded by guinea pig cytomegalovirus gp38.1 in cell culture and in animals

Cytomegaloviruses (CMVs) employ an array of strategies designed to interfere with host defence responses against pathogens. Studies on such evasion mechanisms are important for understanding the pathogenesis of CMV diseases. Although guinea pig CMV (GPCMV) provides a useful animal model for congenital CMV infection, its evasion strategies are not fully elucidated. Here, we analysed a genome locus that may encode gene products for the GPCMV evasion mechanisms and found the following. (1) RACE analyses identified five transcripts in the GP38-gp38.4 locus, one of which was a spliced product encoding gp38.1. Similarities in the splicing pattern and gene position of gp38.1 to human CMV UL37 and its exon 1 encoding vMIA (viral mitochondria-localized inhibitor of apoptosis) suggest that the gp38.1 gene encodes an apoptosis inhibitor. (2) In a transient transfection assay, gp38.1 localized in the mitochondria and relocated BAX from the cytoplasm to the mitochondria, although its co-localization with BAK was not evident. Further, the expression of gp38.1 partially reduced staurosporine-induced apoptosis. (3) GPCMV defective in the gp38.1 ORF (Δ38.1) and the virus that rescues the defect (r38.1) were generated. Guinea pig fibroblast cells infected with Δ38.1 died earlier than r38.1-infected cells, which resulted in the lower yields of Δ38.1. (4) In animals, viral loads in the spleens of r38.1-infected guinea pigs were higher than those in the spleens of Δ38.1-infected animals. In conclusion, although GPCMV gp38.1 exerts a vMIA-like function, its inhibitory effect was not robust, suggesting the presence of additional inhibitory molecule(s), such as a BAK-specific inhibitor.

Congenital CMV-Associated Hearing Loss: Can Brain Imaging Predict Hearing Outcome?

OBJECTIVES

Congenital cytomegalovirus (cCMV) infection is the leading cause of nonhereditary sensorineural hearing loss in childhood and is also associated with CNS abnormalities. The main objective is to investigate the prognostic value of neonatal cranial ultrasound (cUS) and cranial magnetic resonance imaging (cMRI) in predicting long-term hearing outcome in a large cohort of cCMV-infected symptomatic and asymptomatic patients.

DESIGN

Data were prospectively collected from a multicentre Flemish registry of children with cCMV infection born between 2007 and 2016. Neonatal cUS and cMRI scans were examined for lesions related to cCMV infection. Audiometric results at different time points were analyzed. The imaging and audiometric results were linked and diagnostic values of cUS and cMRI were calculated for the different hearing outcomes.

RESULTS

We were able to include 411 cCMV patients, of whom 40% was considered symptomatic at birth. Cranial ultrasound abnormalities associated with cCMV infection were found in 76 children (22.2% of the cUS scans), whereas cMRI revealed abnormalities in 74 patients (26.9% of the cMRI scans). A significant relation could be found between the presence of cUS or cMRI abnormalities and hearing loss at baseline and last follow-up. Cranial ultrasound and cMRI findings were not significantly correlated with the development of delayed-onset hearing loss. Specificity and sensitivity of an abnormal cUS to predict hearing loss at final follow-up were 84% and 43%, respectively compared with 78% and 39% for cMRI. Normal cUS and cMRI findings have a negative predictive value of 91% and 92%, respectively, for the development of delayed-onset hearing loss.

CONCLUSIONS

Neuroimaging evidence of CNS involvement in the neonatal period is associated with the presence of hearing loss in children with a cCMV infection. Imaging abnormalities are not predictive for the development of delayed-onset hearing loss.

Etiology of Childhood Bilateral Sensorineural Hearing Loss in Shandong Province, China

Objectives The purpose of this study is to ascertain the etiology of bilateral sensorineural hearing loss (SNHL) in children aged ≤ 18 years living in Shandong province. Method Data were taken from a cross-sectional study, which was conducted between 2015 and 2017. The study included children aged ≤ 18 years, recruited from special schools for children with hearing loss and from hearing rehabilitation centers in Shandong province of China. Children were screened for bilateral SNHL through audiological testing. Clinical examination, genetic testing, and structured interviews were conducted for those children who were identified as having hearing loss to identify the potential cause. Results The etiology of bilateral SNHL in our sample was genetic in 874 (39.3%), acquired in 650 (29.3%), and unknown in 697 (31.4%) children. Among children with acquired SNHL, the cause was maternal viral infection in 75 (11.5%); perinatal factors in 238 (36.6%); meningitis, measles, and mumps in 146 (22.5%); and ototoxic exposure in 117 (18%) children. Among the children with genetic SNHL, only 44 (4.9%) were identified as having syndromic hearing loss, and the remainder (95.1%) were classified as nonsyndromic hearing loss. Conclusion The findings indicated that nearly 30% of bilateral SNHL in Shandong province could be preventable through immunization, early prenatal diagnosis, proper treatment of infections, and avoidance of prescription of ototoxic drugs. This finding emphasizes the need for programs aimed at improving the health services at primary and secondary levels of health care, which will in turn prevent childhood hearing loss.

Targeted Mutation Analysis of the SLC26A4, MYO6, PJVK and CDH23 Genes in Iranian Patients with AR Nonsyndromic Hearing Loss

BACKGROUND

Hearing loss (HL) is the most prevalent sensory disorder. The over 100 genes implicated in autosomal recessive nonsyndromic hearing loss (ARNSHL) makes it difficult to analyze and determine the accurate genetic causes of hearing loss. We sought to de?ne the frequency of seven hearing loss-Causing causing genetic Variants in four genes in an Iranian population with hearing loss.

MATERIALS AND METHODS

One hundred ARNSHL patients with normal GJB2/GJB6 genes were included, and targeted mutations in SLC26A4, MYO6, PJVK and CDH23 genes were analyzed by ARMS-PCR. The negative and positive results were confirmed by the Sanger sequencing.

RESULTS

We found only two mutations, one in MYO6 (c.554-1 G > A) gene and another in PJVK (c.547C > T).

CONCLUSION

c.554-1G > A and c.547C > T mutations are responsible for 1% each of the Iranian ARNSHL patients. These genes are not a frequent cause of ARNSHL in an Iranian population.

Roles of GP33, a guinea pig cytomegalovirus-encoded G protein-coupled receptor homolog, in cellular signaling, viral growth and inflammation in vitro and in vivo

Cytomegaloviruses (CMVs) encode cellular homologs to evade host immune functions. In this study, we analyzed the roles of GP33, a guinea pig CMV (GPCMV)-encoded G protein-coupled receptor (GPCR) homolog, in cellular signaling, viral growth and pathogenesis. The cDNA structure of GP33 was determined by RACE. The effects of GP33 on some signaling pathways were analyzed in transient transfection assays. The redET two-step recombination system for a BAC containing the GPCMV genome was used to construct a mutant GPCMV containing an early stop codon in the GP33 gene (Δ33) and a rescued GPCMV (r33). We found the following: 1) GP33 activated the CRE- and NFAT-, but not the NFκB-mediated signaling pathway. 2) GP33 was dispensable for infection in tissue cultures and in normal animals. 3) In pregnant animals, viral loads of r33 in the livers, lungs, spleens, and placentas at 6 days post-infection were higher than those of Δ33, although the viruses were cleared by 3 weeks post-infection. 4) The presence of GP33 was associated with frequent lesions, including alveolar hemorrhage in the lungs, and inflammation in the lungs, livers, and spleens of the dams. Our findings suggest that GP33 has critical roles in the pathogenesis of GPCMV during pregnancy. We hypothesize that GP33-mediated signaling activates cytokine secretion from the infected cells, which results in inflammation in some of the maternal organs and the placentas. Alternatively, GP33 may facilitate transient inflammation that is induced by the chemokine network specific to the pregnancy.

Cytomegalovirus (CMV) is a major pathogen that causes congenital diseases, including birth defects and developmental abnormalities in newborns. Better understanding of the immune evasion mechanisms may open the way to the development of new types of live attenuated vaccines for congenital CMV infection. In contrast to murine and rat CMVs, guinea pig CMV (GPCMV) causes infection in utero, which makes GPCMV animal models a useful tool for understanding the pathogenesis of congenital infection and evaluation of vaccine strategies. By constructing a GPCMV mutant lacking GP33, a viral G protein-coupled receptor homolog, this study found that GP33 was involved in the induction of significant inflammatory responses in pregnant but not in normal animals. As GP33 activated the NFAT- and CRE-, but not the NFκB-signal pathway, it is plausible that GP33 enhanced cytokine expression, which results in pathogenic outcomes in the maternal organs and placentas.

Congenital cytomegalovirus infection inducing non-congenital sensorineural hearing loss during childhood; a systematic review

BACKGROUND

Congenital cytomegalovirus (CMV) infection is one of the most important risk factors for delayed onset and progressive hearing loss in children. However, the relevant literature is limited, heterogeneous and currently insufficient to provide guidance toward the effective monitoring of hearing acuity in these children.

OBJECTIVES

The aim of this study was to provide a systematic review focused on types of hearing loss that may escape diagnosis through universal neonatal hearing screening and/or present significant changes during childhood, such as progressive, fluctuating and late-onset hearing loss.

DATA SOURCES

A review of the present literature was conducted via the PubMed database of the US National Library of Medicine (www.pubmed.org) and Scopus database (www.scopus.com) with the search terms "late-onset hearing loss cytomegalovirus", "progressive hearing loss cytomegalovirus" and "fluctuating hearing loss cytomegalovirus".

STUDY ELIGIBILITY CRITERIA

Prospective or retrospective clinical studies were included if they presented a detailed audiological assessment, for a follow-up period of >2years.

METHODS

The prevalence and time of diagnosis of progressive, fluctuating and late-onset hearing loss were considered as primary outcomes. Results were recorded separately for symptomatic and asymptomatic children, when possible.

RESULTS

This analysis refers to a population of 181 children with CMV-induced hearing loss, who were diagnosed among 1089 with congenital CMV infection. The prevalence of CMV-induced hearing loss was significantly higher among symptomatic children (p < 0.0001), who were also significantly more likely to develop bilateral hearing loss (p = 0.001). There was not sufficient information on the prevalence, laterality, degree and time of diagnosis of progressive, fluctuating and late-onset hearing loss that could constitute the basis toward the report of specific follow-up guidelines.

CONCLUSIONS

Further studies are needed in order to understand and quantify the potential effects of congenital CMV infection in the inner ear and hearing acuity. The results presented in the relative studies should be very carefully evaluated and compared to each other, since they correspond to substantially different cohorts, study designs, and result elaboration. Infants with congenital CMV infection should be closely monitored, regarding their hearing acuity at least during their preschool years, although substantial changes in hearing thresholds have been reported as late as the 16th year of age. Parental counseling is of outmost importance in order to minimize the numbers of children lost to follow-up.

A two-step culture method utilizing secreted luciferase recombinant virus for detection of anti-cytomegalovirus compounds

Quantification of human cytomegalovirus (HCMV) replication by plaque assay reflects viral infectivity but has several drawbacks. Recombinant virus expressing reporter genes can facilitate quantification of HCMV replication. In this study, a recombinant virus, Towne-BAC(dTT)-MetLuc, was constructed and the secretable Metridia luciferase (MetLuc) gene inserted into it under UL146 promoter. In addition, the UL130 gene was repaired to allow growth of the recombinant virus in both fibroblasts and epithelial cells. As predicted, luciferase activity was secreted into the culture medium and correlated with virus replication in infected fibroblasts and epithelial cells. Furthermore, secreted luciferase activity was correlated with the size of the recombinant virus inoculum with a dynamic range of 3 logs. This recombinant virus was used in a two-step culture protocol for detection of the anti-HCMV activity of compounds; that is, the supernatant of a first-step culture with anti-viral compounds was collected and inoculated into uninfected cells to create a second-step culture. Although secreted luciferase activity leaked in the first-step culture supernatant in the presence of some antiviral compounds, luciferase activity in the second-step culture supernatant reflected the virus yield in the first-step culture. Therefore, comparison of luciferase activity in the first- and second-step cultures indicated the anti-viral activity of the compounds. This two-step culture protocol facilitates screening of anti-viral compounds.

Differences in the effects of mutations in GP131, a guinea pig cytomegalovirus homologue of pentameric complex component UL130, on macrophage and epithelial cell infection

As congenital cytomegalovirus (CMV) infection is the major cause of developmental abnormalities in children, the development of effective vaccines is critical to public health. Recent studies have demonstrated that the pentameric complex (Pentamer) of glycoproteins, which is required for human CMV infection of endothelial and epithelial cells, could be a potent vaccine antigen. As guinea pig CMV (GPCMV) infects congenitally and encodes homologues of all Pentamer components, GPCMV models are considered to be useful for the development of vaccine strategies. Here, to clarify the precise requirement of GP131, one of the GPCMV Pentamer components, for the infection of epithelial cells and macrophages, we prepared several mutants with a charged amino acid-to-alanine alteration in GP131 and found some differences in the effects of the mutations on the infection of the two cell types, suggesting the existence of cell type-dependent recognition or function of Pentamer in GPCMV infection.

[A 15-year-old girl with congenital cytomegalovirus infection presenting with sensorineural hearing impairment and cerebral while matter lesions but no intellectual disability]

A 15-year-old girl presented with non-progressive sensorineural hearing impairment in her right ear since her early childhood. She had normal intellectual development. When she was 15 years old, small deep white matter lesions around the lateral ventricles were incidentally detected in brain MRI studies through further investigation of auditory organs. Laboratory data including cerebrospinal fluid analysis and antibodies to aquaporin-4 or myelin-oligodendrocyte glycoprotein were normal. She was diagnosed as a congenital cytomegalovirus (CMV) infection based on the detection of CMV DNA from preserved umbilical cord tissue by real-time polymerase chain reaction. It should be kept in mind that a case of congenital CMV infection with normal intelligence may be underdiagnosed and that sensorineural hearing impairment from early childhood and deep white matter abnormalities can be key features giving rise to suspicion on congenital CMV infection.

Human CD134 (OX40) expressed on T cells plays a key role for human herpesvirus 6B replication after allogeneic hematopoietic stem cell transplantation

BACKGROUND

CD134 (OX40), which is a cellular receptor for human herpesvirus-6B (HHV-6B) and expresses on activated T cells, may play a key role for HHV-6B replication after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

OBJECTIVES

Therefore, we examined the CD134 expression on T cells and HHV-6B replication after allo-HSCT, and analyzed the correlation between them.

STUDY DESIGN

Twenty-three patients after allo-HSCT were enrolled. The percentages of CD134-positive cells within the CD4⁺ and CD8⁺ cell populations were measured by flow cytometry, and the viral copy number of HHV-6B was simultaneously quantified by real-time PCR. The correlation between CD134 and HHV-6B viral load was then statistically analyzed.

RESULTS

HHV-6B reactivation occurred in 11 of 23 patients (47.8%). CD134 expression was seen on T cells and was coincident with the time of peak viral load. The percentage of CD134-positive cells decreased significantly when HHV-6B DNA disappeared (p = .005 in CD4⁺ T cells, p = .02 in CD8⁺ T cells). In the 4 patients who underwent umbilical cord blood transplantation (UCBT), the viral load varied with the percentage of CD134-positive cells. In the comparison between the HHV-6B reactivation group and non-reactivation group, maximum percentages of CD134-positive cells among CD4⁺ T cells in reactivation group were significantly higher than those in non-reactivation group (p = .04).

CONCLUSIONS

This is the first study to show that a correlation of CD134 expression on T cells with HHV-6B replication after allo-HSCT, especially in UCBT. The results possibly indicate that CD134 on T cells plays a key role for HHV-6B replication after allo-HSCT.

Vaccine Development for Cytomegalovirus

The development of a cytomegalovirus (CMV) vaccine has become a top priority due to its potential cost-effectiveness and associated public health benefits. However, there are a number of challenges facing vaccine development including the following: (1) CMV has many mechanisms for evading immune responses , and natural immunity is not perfect, (2) the immune correlates for protection are unclear, (3) a narrow range of CMV hosts limits the value of animal models, and (4) the placenta is a specialized organ formed transiently and its immunological status changes with time. In spite of these limitations, several types of CMV vaccine candidate, including live-attenuated, DISC , subunit, DNA, vectored, and peptide vaccines, have been developed or are currently under development. The recognition of the pentameric complex as the major neutralization target and identification of various strategies to block viral immune response evasion mechanisms have opened new avenues to CMV vaccine development. Here, we discuss the immune correlates for protection, the characteristics of the various vaccine candidates and their clinical trials, and the relevant animal models.

Congenital cytomegalovirus in Japan: More than 2 year follow up of infected newborns

BACKGROUND

The aim of this study was to evaluate the outcome of congenital cytomegalovirus (CMV) infection identified on urine-filter screening assay at >2 years' follow up, and to observe the clinical outcomes after anti-CMV treatment.

METHODS

Sixty of 72 congenital CMV patients were enrolled and clinically observed for >2 years. Forty-three were asymptomatic at birth; seven were symptomatic at birth but untreated with anti-CMV drugs; and 10 were symptomatic and treated with anti-CMV drugs.

RESULTS

Of the 43 asymptomatic patients, three developed hearing loss or language disability for which association with congenital CMV has been repeatedly reported, and two had neurological sequelae of which the etiology was unclear, indicating that the rate of CMV-associated late-onset sequelae was 7-12%. All seven symptomatic infants without treatment developed sequelae, while three of the 10 treated patients were free from any sequelae.

CONCLUSIONS

The rate of late-onset sequelae observed in Japan is similar to that reported in the USA and Europe. The treatment of symptomatic patients with antiviral agents results in favorable clinical outcomes. Thus, newborn urine-filter paper screening of congenital CMV infection is warranted.

Newborn Congenital Cytomegalovirus Screening Based on Clinical Manifestations and Evaluation of DNA-based Assays for In Vitro Diagnostics

OBJECTIVES

To establish a strategy for congenital cytomegalovirus (cCMV) screening and to establish confirmatory assays approved as in vitro diagnostics by the regulatory authorities, we evaluated the clinical risks and performance of diagnostic assays developed by commercial companies, since cCMV infection has significant clinical consequences.

STUDY DESIGN

Newborns with clinical manifestations considered to be consequences of cCMV infection (n = 575) were screened for the presence of cytomegalovirus (CMV) DNA in urine specimens collected onto filter paper placed in their diapers using the polymerase chain reaction-based assay reported previously. Liquid urine specimens were obtained from all of 20 CMV-positive newborns and 107 of the CMV-negative newborns identified in the screening. We used these 127 specimens, as well as 12 from cCMV cases identified in a previous study and 41 from healthy newborns, to compare the performance of 2 commercial assays and 1 in-house assay.

RESULTS

The risk-based screening allowed the identification of cCMV cases at least 10-fold more efficiently than our previous universal screening, although there appears to be a limit to the identification of asymptomatically infected newborns. Although CMV-specific IgM during pregnancy was found frequently in mothers of cCMV newborns, CMV-IgM alone is not an effective diagnostic marker. The urine-filter-based assay and the 3 diagnostic assays yielded identical results.

CONCLUSIONS

Although risk-based and universal newborn screening strategies for cCMV infection each have their respective advantages and disadvantages, urine-filter-based assay followed by confirmatory in vitro diagnostics assays is able to identify cCMV cases efficiently.

The first sporadic case of DFNA11 identified by next-generation sequencing

We report the first sporadic case of nonsyndromic autosomal dominant hearing loss (DFNA11). The patient was a 5-year-old boy with moderate bilateral hearing loss. Targeted next-generation sequencing analysis of patient DNA identified a known heterozygous DFNA11 mutation, c.689C > T, in MYO7A, encoding p.Ala230Val. The mutation was not detected in the parents of the patient and is considered to be de novo. This mutation is identical to the one reported previously in an Italian family. Accumulation of mutation data increases the feasibility of identifying autosomal dominant mutations in sporadic sensorineural hearing loss.

Interaction of Immunoglobulin with Cytomegalovirus-Infected Cells

Intravenous immunoglobulin (IVIG) is used to treat or prevent severe viral infection, especially cytomegalovirus (CMV) infections. IVIG was characterized to understand its interaction with CMV-infected cells. IVIG retarded CMV spread and reduced virus yields depending on the neutralizing (NT) antibody titer. Immediate early protein synthesis was reduced by IVIG in 3 to 15 h, and IVIG specifically reduced the ratio of 66/68k protein synthesis among immediate early proteins in an NT antibody-dependent manner between 4 and 8 h after infection, indicating that antigenic modulation of CMV-infected cells by IVIG reduced viral protein synthesis and virus production. The half-life of antibody bound to CMV-infected cells was 3.8 h. NT antibody titers to varicella-zoster virus (VZV) and CMV in IVIG were dose dependently absorbed by cells infected with VZV and CMV, respectively, but the antibody titers to CMV and VZV, respectively, were not affected. NT antibody in 0.3 mL of IVIG (15 mg) was specifically absorbed by 10⁸ CMV-infected cells and 10⁷ VZV-infected cells, suggesting that the NT antibody in IVIG might be inactivated by one-tenth of a similar volume of CMV-infected or VZV-infected cells. Various antiviral activities of IVIG may contribute to control and alleviation of CMV infection.

TORCH Antibodies Among Pregnant Women and Their Newborns Receiving Care at Kilimanjaro Christian Medical Centre, Moshi, Tanzania

Background:

Toxoplasmosis, other (syphilis, varicella-zoster, parvovirus B19, and hepatitis B), rubella, cytomegalovirus (CMV), and herpes simplex virus type 1 and type 2 (HSV-1 and HSV-2) – known by the acronym TORCH – is a group of infections affecting both mothers and their unborn babies with adverse short- and long-term outcomes. The majority of infected mothers are asymptomatic, which leaves only speculation as to the probable cause of many congenital anomalies, stillbirths, prematurity, and death resulting from TORCH infections. The main objective of this study was to investigate previous exposure to TORCH infections by measuring the seroprevalence of TORCH antibodies in pregnant women and their newborns receiving care at Kilimanjaro Christian Medical Centre (KCMC), Moshi, Tanzania.

Methods:

This was a cross-sectional, hospital-based study conducted at KCMC from December 2013 to April 2014. Of 350 pregnant women enrolled in the study, we tested 347 pregnant women attending the antenatal clinic and who opted to deliver at KCMC. Cord blood was collected and analysed for 309 of their newborns. To identify immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies in mothers and IgM antibodies in newborns, we used enzyme-linked immunosorbent assay testing. A structured questionnaire was used to collect data of mothers and their newborns. Data analysis was done using SPSS version 20.

Results:

The seroprevalence of IgG antibodies to TORCH infections among pregnant women was 154 (44.4%) for toxoplasmosis, 311 (89.6%) for rubella, 343 (98.6%) for CMV, and 346 (99.7%) for HSV-1 and HSV-2; 141 (40.6%) had been exposed to all 4 infections. For HSV-1 and HSV-2, the IgM antibodies were found in 137 (39.5%) of the 347 pregnant women included in this study. Age above 35 years (OR 6.15; 95% CI, 1.22–31.1; P=.028) and multiparity (OR 1.63; 95% CI, 1.01–2.62; P=.045) were associated with higher risk of being exposed to all TORCH infections. A total of 11 newborns had IgM antibodies to HSV-1 and HSV-2 giving a seroprevalence of 3.6%, and one newborn had IgM antibodies to rubella, giving a seroprevalence of 0.3%. None of the newborns had antibodies to toxoplasmosis and CMV.

Conclusion:

Exposure to TORCH infections was high among pregnant women in our population. Older age and multi-parity were associated with a higher risk of being exposed to all TORCH infections. Seroprevalence to HSV-1 and HSV-2 was high in newborns. The higher IgM antibodies to HSV-1 and HSV-2 among pregnant mothers and their newborns may disturb maternal, fetal, and neonatal health, and therefore we recommend establishing treatment protocol to support management of pregnant women and newborns who are seropositive for IgM antibodies.

Audiovestibular consequences of congenital cytomegalovirus infection

Congenital cytomegalovirus (CMV) infection is the second most frequent cause of mental retardation and sensorineural hearing loss, after genetic factors. Recently, pediatric forensic and fetopathological studies have led to progress in understanding the pathophysiological mechanisms underlying the various neurosensory sequelae. Thanks to the identification of certain prognostic factors of hearing loss, therapeutic protocols based on antiviral molecules are now proposed for target populations. This treatment has shown efficacy in limiting hearing threshold deterioration and even, in some cases, seems to provide partial recovery of hearing in symptomatic congenitally infected CMV neonates. However, optimal treatment duration and administration modalities are not clearly defined. This article reviews recent data concerning audiovestibular sequelae and their management in children congenitally infected by CMV.

An Ex vivo culture model for placental cytomegalovirus infection using slices of Guinea pig placental tissue

Congenital infection with human cytomegalovirus (CMV) through the placenta is one of the major causes of birth and developmental abnormalities. Guinea pig CMV (GPCMV) causes in utero infection, which makes its animal models useful for studies on congenital diseases. Here, we established an ex vivo culture method for tissue slices prepared from guinea pig placentas and demonstrated that viral spread in the model resembles those in the placenta of GPCMV-infected animals and that the infection is independent of the pentameric glycoprotein complex for endothelial/epithelial cell tropism. Thus, this model affords a useful tool for pathobiological studies on CMV placental infection.

Presence of cytomegalovirus in the perilymphatic fluid of patients with profound sensorineural hearing loss caused by congenital cytomegalovirus infection

CONCLUSION

Not all patients diagnosed with congenital infection using umbilical cord assay were found to be positive for CMV-DNA by perilymphatic fluid assay. In addition, a CMV-DNA-positive result was observed in one patient who had not been diagnosed with congenital infection. Sampling of perilymphatic fluid from a large population of patients with congenital SNHL caused by congenital CMV infection or of unknown etiology is required to determine the prevalence of CMV-related profound HL.

OBJECTIVES

Sensorineural hearing loss (SNHL) is one of the most frequent manifestations in patients with congenital cytomegalovirus (CMV) infection. Using dried umbilical cord, a PCR-based assay was recently developed for the retrospective detection of congenital CMV infection. This study analyzed the presence of CMV in the perilymphatic fluid and evaluated differences in the effect of cochlear implantation between CMV-positive and -negative groups.

METHOD

Perilymphatic fluid was collected from each patient at the time of cochlear implantation and analyzed for the presence of CMV using a PCR method.

RESULTS

The perilymphatic fluid in two of the five patients suffering from congenital CMV infection and in one of the 17 patients without congenital CMV infection was found to be positive for CMV.

Timeliness of service delivery for children with later-identified mild-to-severe hearing loss

PURPOSE

In this study, the authors examined diagnostic and intervention services for children identified with hearing loss (HL) after the newborn period.

METHOD

The authors compared ages at service delivery and length of delays between service delivery steps for 57 later-identified children with HL and 193 children who referred for assessment from the newborn hearing screen (NHS). For only later-identified children, regression models were used to investigate relationships among predictor variables and dependent variables related to service delivery.

RESULTS

Children who referred from the NHS received follow-up services at younger ages than later-identified children. Later-identified children had significantly longer delays from HL confirmation to entry into early intervention, compared to children who referred from the NHS. For later-identified children, degree of HL predicted ages at follow-up clinical services. Children with more severe HL received services at younger ages compared to children with milder HL. Gender predicted the length of the delay from confirmation to entry into early intervention, with girls demonstrating shorter delays.

CONCLUSIONS

The current results lend support to the need for ongoing hearing monitoring programs after the neonatal period, particularly when children enter early intervention programs because of language/developmental delays.

Restricted infection of murine cytomegalovirus (MCMV) in neonatal mice with MCMV-induced sensorineural hearing loss

BACKGROUND

Congenital infection with human Cytomegalovirus (HCMV) is known to be a causative agent of sensorineural hearing loss (SNHL).

OBJECTIVES

To clarify the nongenetic etiology of SNHL by identifying the Cytomegalovirus (CMV)-infected region in the cochleae.

STUDY DESIGN

We established an animal model of SNHL by injecting neonatal Balb/c mice with intracerebral murine Cytomegalovirus (MCMV) within 24h after delivery.

RESULTS

At 3 weeks of age, unilateral and bilateral SNHL were observed in 24% (5/21) and 29% (6/21) of the mice, respectively. SNHL thereafter progressed, with 79% of mice developing bilateral SNHL by 6 weeks of age. MCMV antigens and DNA were detected in the spiral ganglion, and cells surrounding the meninges and scala tympani at 1 week of age. However, both MCMV antigens and DNA had completely disappeared by 2 weeks of age. It is possible that the MCMV reached the spiral ganglion via cerebrospinal fluid as the result of meningitis, as the stria vascularis was found to be MCMV antigen negative. Myosin VI expression in the outer hair cells was lost at 3 weeks of age. MCMV and myosin VI expression disappeared before and during SNHL progression, respectively.

CONCLUSIONS

There was a definite lag time between the period in which MCMV antigens/DNA-positive cells were observed and that in which SNHL developed and myosin VI-negative hair cells were observed. Further study is needed to explore the role of MCMV in the loss of myosin VI expression in the outer hair cells.

Hearing loss and congenital CMV infection: a systematic review

BACKGROUND AND OBJECTIVE

Hearing loss caused by congenital cytomegalovirus (cCMV) infection was first observed in 1964. Today cCMV is the most common cause of nonhereditary sensorineural hearing loss in childhood. Our objective was to provide an overview of the prevalence of cCMV-related hearing loss, to better define the nature of cCMV-associated hearing loss, and to investigate the importance of cCMV infection in hearing-impaired children.

METHODS

Two reviewers independently used Medline and manual searches of references from eligible studies and review articles to select cohort studies on children with cCMV infection with audiological follow-up and extracted data on population characteristics and hearing outcomes.

RESULTS

Thirty-seven studies were included: 10 population-based natural history studies, 14 longitudinal cohort studies, and 13 retrospective studies. The prevalence of cCMV in developed countries is 0.58% (95% confidence interval, 0.41-0.79). Among these newborns 12.6% (95% confidence interval, 10.2-16.5) will experience hearing loss: 1 out of 3 symptomatic children and 1 out of 10 asymptomatic children. Among symptomatic children, the majority have bilateral loss; among asymptomatic children, unilateral loss predominates. In both groups the hearing loss is mainly severe to profound. Hearing loss can have a delayed onset, and it is unstable, with fluctuations and progression. Among hearing-impaired children, cCMV is the causative agent in 10% to 20%. Despite strict selection criteria, some heterogeneity was found between selected studies.

CONCLUSIONS

This systematic review underscores the importance of cCMV as a cause of sensorineural hearing loss in childhood.

Guinea pig cytomegalovirus GP129/131/133, homologues of human cytomegalovirus UL128/130/131A, are necessary for infection of monocytes and macrophages

The GP129, GP131 and GP133 genes of guinea pig cytomegalovirus (GPCMV) are homologues of human cytomegalovirus UL128, UL130 and UL131A, respectively, which are essential for infection of endothelial and epithelial cells, and for viral transmission to leukocytes. Our previous study demonstrated that a GPCMV strain lacking the 1.6 kb locus that contains the GP129, GP131 and GP133 genes had a growth defect in animals. Here, we demonstrated that the WT strain, but not the 1.6 kb-deleted strain, formed capsids in macrophages prepared from the peritoneal fluid. To understand the mechanism, we prepared GPCMV strains defective in each of GP129, GP131 and GP133, and found that they were all essential for the infection of peritoneal, splenic and PBMC-derived macrophages/monocytes, and for expression of immediate-early antigens in the macrophages/monocytes, although they were dispensable for infection of fibroblasts. Monocyte/macrophage tropism could be one of the important determinants for viral dissemination in vivo.

Feasibility and acceptability of targeted screening for congenital CMV-related hearing loss

BACKGROUND

Congenital cytomegalovirus (cCMV) is the most common non-genetic cause of sensorineural hearing loss (SNHL) in children. Ganciclovir has been shown to prevent the continued deterioration in hearing of children with symptomatic cCMV, but some children with cCMV-related SNHL are unidentified in the neonatal treatment period. Neonatal cCMV screening provides an opportunity to identify infants with cCMV-related SNHL who might benefit from early treatment.

OBJECTIVES

To assess the feasibility (ability to take samples before 3 weeks of age and clinical assessment by 30 days of age) and acceptability (maternal anxiety) of targeted CMV testing of infants who are 'referred' for further audiological testing after routine newborn hearing screening programme (NHSP).

METHODS

Parents of infants who have 'no clear responses' on routine NHSP before 22 days of life in London and North East England were approached. Salivary and urine samples were tested by CMV PCR. At recruitment and 3 months, the short form Spielberger State-Trait Anxiety Inventory measured maternal anxiety.

RESULTS

411 infants were recruited. 99% (407/411) returned a sample; 98% (404/411) successfully yielded a CMV result, 6 had cCMV, all diagnosed on salivary samples taken <22 days of age (1.5%; 95% CI 0.6% to 3.2%). Only 50% returned urine samples compared with 99% returning salivary samples (p<0.001). Using saliva swabs 98% were successfully screened for CMV within 3 weeks. All positive screening CMV results were known by day 23, and 5/6 infants with cCMV were assessed within 31 days. Anxiety was not increased in mothers of infants screened for cCMV.

CONCLUSIONS

Targeted salivary screening for cCMV within the NHSP is feasible, acceptable and detects infants with cCMV-related SNHL who could benefit from early treatment.

Detection of human herpesviruses in the cerebrospinal fluid from patients diagnosed with or suspected of having progressive multifocal leukoencephalopathy

BACKGROUND

Progressive multifocal leukoencephalopathy (PML), a fatal demyelinating disease caused by JC virus (JCV), occurs mainly in immunocompromised patients. While JCV DNA is detected in the cerebrospinal fluid (CSF) from a certain proportion of patients suspected of having PML, JCV-negative patients may also develop brain lesions due to other infectious agents. This study assessed the prevalence of six herpesviruses in the CSF from patients diagnosed with or suspected of PML.

METHODS

Two hundred and ninety-nine CSF specimens and clinical data were collected from 255 patients, including 31 confirmed PML cases. Quantitative PCR assays were carried out to detect the genomic DNA of JCV, herpes simplex virus (HSV), varicella-zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus 6 (HHV-6).

RESULTS

Herpesvirus DNAs were detected in the CSF specimens from 29 of 255 patients (11.4%). HSV-1 and CMV were detected in JCV-negative patients, whereas VZV and EBV were detected in both CSF JCV-positive and -negative individuals. The herpesvirus-positive patients had underlying disorders that caused immunosuppression, such as HIV infection, congenital immunodeficiencies, and hematologic malignancies, and presented with neurologic symptoms and MRI lesions, mainly in the cerebral white matter. The median values of CSF cell counts and protein levels in the herpesvirus-positive patients were slightly higher than those in the PML patients.

CONCLUSIONS

The results demonstrate that herpesviruses are occasionally detected in the CSF from PML patients and immunocompromised individuals suspected of having PML. Thus, this study provides a significant basis for the diagnosis and treatment of neurological disorders in immunocompromised patients.

Development and padronization of three multiplex PCRs for the diagnosis of Chlamydia trachomatis, Toxoplasma gondii, herpes simplex viruses 1 and 2, and Cytomegalovirus

To develop multiplex PCRs (mPCRs) that allows simultaneous diagnosis of the infectious agents Chlamydia trachomatis, Toxoplasma gondii, HSV 1/2, and Cytomegalovirus (CMV). The study included patients with clinical suspicion of these agents, and clinical samples were blood, cerebrospinal fluid, urine, vaginal swabs, and amniotic fluid. After the extraction of DNA, this was used as a template in amplification by PCR of selected genes. The following conditions were tested: primer concentration, MgCl2 concentration, and annealing temperature. Three mPCRs were developed: multiplex I (CMV, HSV 1/2), multiplex II (CMV, HSV 1/2, T. gondii), and multiplex III (C. trachomatis, T. gondii, HSV 1/2, and CMV). The primer pairs used were shown to be specific for each infectious agent, and the specificity of mPCR assays was 100 %. Both the reactions of the monoplex PCR and mPCR produced a detection limit of 2 × 10(-5) to 6 × 10(-7) ng/μl of different DNAs. Upon conclusion, amplified products of expected size were obtained in 3 different reactions, and all the infectious agents were detected simultaneously in each mPCR. The concordant results of the study suggest that mPCR can be a powerful tool to improve the diagnostics of infectious diseases.

Does congenital cytomegalovirus infection lead to hearing loss by inducing mutation of the GJB2 gene?

BACKGROUND

Congenital cytomegalovirus (CMV) infection and mutation of the gap junction β-2 (GJB2) gene are important causes of sensorineural hearing loss (SNHL). This study aims to determine if congenital CMV infection leads to deafness by inducing GJB2 mutation.

METHODS

GJB2 gene sequencing and auditory brainstem response testing were performed in 159 neonates (63 with and 96 without CMV infection) from August 2008 to August 2011. For neonates with GJB2 mutation, their parents were further screened for GJB2 sequence.

RESULTS

The incidence of SNHL was 12.7% in CMV-infected but 0% in uninfected children aged 1-1.5 y (P = 0.000). Similar mutation rates of the GJB2 gene were observed in neonates with or without CMV infection (34.9 vs. 32.3%, respectively, P = 0.734). No significant difference in the mutation rate of GJB2 was found among neonates with CMV infection and SNHL, those with CMV infection and normal hearing, and uninfected newborns with normal hearing (P = 0.438). Mutations 79G>A, 109G>A, 341A>G, and 608T>C were found in neonates with and without CMV infection. All of the above mutations were also found in both or one of the corresponding parents.

CONCLUSION

Congenital CMV infections may cause deafness in neonates, but this might be independent of GJB2 gene mutation.

Polymorphisms in TLR-2 are associated with congenital cytomegalovirus (CMV) infection but not with congenital CMV disease

BACKGROUND

Cytomegalovirus (CMV) is the most common cause of congenital virus infection. However, the risk factors for infection in utero and for progression to a severe clinical outcome remain uncertain. Recent studies have identified associations of specific single nucleotide polymorphisms (SNPs) in Toll-like receptor (TLR) genes with susceptibility to infections of some viruses and with their clinical outcome.

METHODS

Genetic polymorphisms in the TLR-2, TLR-4, and TLR-9 genes were analyzed in 87 children with congenital CMV infections by the TaqMan allelic discrimination assay. The frequencies of genotypes in the general Japanese population were obtained from the National Center for Biotechnology Information (NCBI) databases. Associations between the analyzed SNPs and congenital CMV infection or disease were evaluated.

RESULTS

The CC genotype at SNP rs3804100 in the TLR-2 gene was significantly associated with congenital CMV infection but not with congenital CMV disease. Furthermore, the AG genotype at SNP rs1898830 in the TLR-2 gene tended to be identified less frequently in children with congenital CMV infection. There were no statistically significant associations between SNPs in the TLR-4 and TLR-9 genes and congenital CMV infection or disease.

CONCLUSION

TLR-2 polymorphisms may have some association with congenital CMV infection, although the mechanism underlying this effect remains to be clarified.

Effects of immunization of pregnant guinea pigs with guinea pig cytomegalovirus glycoprotein B on viral spread in the placenta

BACKGROUND

Cytomegalovirus (CMV) is the most common cause of congenital virus infection. Infection of guinea pigs with guinea pig CMV (GPCMV) can provide a useful model for the analysis of its pathogenesis as well as for the evaluation of vaccines. Although glycoprotein B (gB) vaccines have been reported to reduce the incidence and mortality of congenital infection in human clinical trials and guinea pig animal models, the mechanisms of protection remain unclear.

METHODS

To understand the gB vaccine protection mechanisms, we analyzed the spread of challenged viruses in the placentas and fetuses of guinea pig dams immunized with recombinant adenoviruses expressing GPCMV gB and β-galactosidase, rAd-gB and rAd-LacZ, respectively.

RESULTS

Mean body weight of the fetuses in the dams immunized with rAd-LacZ followed by GPCMV challenge 3 weeks after immunization was 78% of that observed for dams immunized with rAd-gB. Under conditions in which congenital infection occurred in 75% of fetuses in rAd-LacZ-immunized dams, only 13% of fetuses in rAd-gB-immunized dams were congenitally infected. The placentas were infected less frequently in the gB-immunized animals. In the placentas of the rAd-LacZ- and rAd-gB-immunized animals, CMV early antigens were detected mainly in the spongiotrophoblast layer. Focal localization of viral antigens in the spongiotrophoblast layer suggests cell-to-cell viral spread in the placenta. In spite of a similar level of antibodies against gB and avidity indices among fetuses in each gB-immunized dam, congenital infection was sometimes observed in a littermate fetus. In such infected fetuses, CMV spread to most organs.

CONCLUSIONS

Our results suggest that antibodies against gB protected against infection mainly at the interface of the placenta rather than from the placenta to the fetus. The development of strategies to block cell-to-cell viral spread in the placenta is, therefore, required for effective protection against congenital CMV infection.

Risk of cytomegalovirus-associated sequelae in relation to time of infection and findings on prenatal imaging

OBJECTIVE

To determine the outcome of pregnancies with documented fetal cytomegalovirus (CMV) infection with and without abnormal findings on ultrasound examination and magnetic resonance imaging (MRI).

METHODS

In this prospective cohort study of pregnant women with documented fetal CMV infection, vertical CMV transmission occurred during the first and second trimesters following primary maternal infection. Patients underwent serial prenatal ultrasound scans and fetal MRI. All neonates underwent ocular fundus examination, ultrasound brain scan and hearing evaluation, and were then followed periodically by a pediatrician.

RESULTS

Primary CMV infection occurred during the first and second trimesters of pregnancy in 71 and 74 patients, respectively. Seven patients (4.8%) decided to terminate pregnancy because of prenatal findings and one neonate died because of CMV complications. Patients with first-trimester infection had infants with significantly more associated sequelae (either auditory damage or neurodevelopmental disabilities) than did patients with second-trimester infection (19.7% vs 5.6%, respectively; P = 0.01). Abnormal prenatal findings on ultrasound examination were associated with increased risk of sequelae. When both ultrasound and MRI findings were normal, the rate of sequelae was decreased to 15.6% for first-trimester infections and to 2.0% for second-trimester infections, partial hearing loss being the sequela in most cases. In the presence of abnormal ultrasound and/or MRI findings the risk was 25% and 16%, respectively, and in most cases the sequelae were deafness and neurodevelopmental delay. The rate of intrauterine growth restriction (IUGR) in the study group was 11.7% and was not affected by the time of onset of maternal infection. Isolated IUGR was not associated with increased risk of sequelae.

CONCLUSION

The risk of sequelae is higher following first-than second-trimester CMV infection. However, the risk of severe sequelae is significantly reduced in the presence of normal prenatal ultrasound and MRI findings.

Characterization of the guinea pig CMV gH/gL/GP129/GP131/GP133 complex in infection and spread

In human cytomegalovirus (HCMV), the UL128-131A locus plays an essential role in cellular tropism and spread. Here, we report the complete annotation of the GP129-133 locus from guinea pig cytomegalovirus (GPCMV) and the discovery of the UL131A homolog, named GP133. We have found that similar to HCMV the GP129-133 proteins form a pentamer complex with the GPCMV glycoproteins gH and gL. In addition, we find that the GP129-133 proteins play a critical role in entry as the GP129-133 deletion mutant shows a defect in both endothelial and fibroblast cell entry. Although the GP129-133 deletion strain can propagate in vitro, we find that the deletion fails to spread in vivo. Interestingly, the wildtype strain can spontaneously give rise to the GP129-133 deletion strain during in vivo spread, suggesting genetic instability at this locus.

Congenital cytomegalovirus is the second most frequent cause of bilateral hearing loss in young French children

OBJECTIVE

To estimate the prevalence of congenital cytomegalovirus (cCMV) among causes of bilateral hearing loss in young French children.

STUDY DESIGN

Children <3 years old with hearing loss were prospectively included at their first visit to a referral center. Cytomegalovirus polymerase chain reaction was performed on dried blood spots from Guthrie cards. Medical records were reviewed.

RESULTS

One hundred children with bilateral hearing loss were included at a median age of 15 months; the prevalence of cCMV was 8% (8/100) (95% CI, 2.7%-13.3%) in this population and 15.4% (8/52) in the subpopulation of children with profound bilateral hearing loss. Delayed neurodevelopment and brain abnormalities on computed tomography scan were found more often in children with cCMV than in children with hearing loss without cCMV (P = .027, P = .005). In 6 of 8 cCMV cases, cCMV infection had not been diagnosed before the study.

CONCLUSIONS

In a comprehensive study of the causes of bilateral hearing loss in young French children, cCMV is the second most frequent cause of hearing loss after connexin mutations. It underlines that a majority of French children with hearing loss and cCMV are not diagnosed early and therefore may not benefit from early intervention including the possibility of neonatal antiviral treatment. These results make the case for promoting systematic cytomegalovirus screening in neonates with confirmed hearing loss identified through neonatal hearing screening.

Coordination of late gene transcription of human cytomegalovirus with viral DNA synthesis: recombinant viruses as potential therapeutic vaccine candidates

INTRODUCTION

During productive infection, human cytomegalovirus (HCMV) genes are expressed in a temporal cascade, with temporal phases designated as immediate-early (IE), early, and late. The major IE (MIE) genes, UL123 and UL122 (IE1/IE2), play a critical role in subsequent viral gene expression and the efficiency of viral replication. The early viral genes encode proteins necessary for viral DNA replication. Following viral DNA replication, delayed-early and late viral genes are expressed which encode structural proteins for the virion. The late genes can be divided into two broad classes. At early times the gamma-1 or leaky-late class are expressed at low levels after infection and are dramatically upregulated at late times. In contrast, the gamma-2 or 'true' late genes are expressed exclusively after viral DNA replication. Expression of true late (gamma-2 class) viral genes is completely prevented by inhibition of viral DNA synthesis.

AREAS COVERED

This review addresses the viral genes required for HCMV late gene transcription. Recombinant viruses that are defective for late gene transcription allow for early viral gene expression and viral DNA synthesis, but not infectious virus production. Since current HCMV prophylaxis is limited by several shortcomings, the use of defective recombinant viruses to induce HCMV cell-mediated and humoral immunity is discussed.

EXPERT OPINION

HCMV DNA replication and late gene transcription are not completely linked. Viral-encoded trans-acting factors are required. Recombinant viruses proficient in MIE and early viral gene expression and defective in late gene expression may be an alternative therapeutic vaccine candidates for the induction of cell-mediated and humoral immunity.

Anti-viral effects of urosolic acid on guinea pig cytomegalovirus in vitro

This study examined the anti-viral effect of ursolic acid on guinea pig cytomegalovirus (GPCMV) and explored the steps of viral replication targeted by ursolic acid. Cytopathic effect assay and MTT method were employed to determine the 50% cellular cytotoxicity (CC(50)), 50% effective concentration (EC(50)) and therapeutic index (TI) with GPCMV. To investigate the specific anti-viral effect of ursolic acid at different temperatures and time points, two other medicines, ganciclovir and Jinyebaidu (JYBD), serving as controls, were studied for comparison. Our results showed that the CC50 of ganciclovir, JYBD and ursolic acid were 333.8, 3015.6, 86.7 μg/mL, respectively; EC(50) of ganciclovir, JYBD and ursolic acid was 48.1, 325.5 and 6.8 μg/mL, respectively; TI of ganciclovir, JYBD and ursolic acid was 7, 9, 13, respectively. Similar with ganciclovir, ursolic acid could inhibit the viral synthesis, but did not affect the viral adsorption onto and penetration into cells. We are led to conclude that the anti-cytomegalovirus effect of ursolic acid is significantly stronger than ganciclovir or JYBD, and the cytotoxic effect of ursolic acid lies in its ability to inhibit viral synthesis.

Cytomegalovirus DNA detection in dried blood spots and perilymphatic fluids from pediatric and adult cochlear implant recipients with prelingual deafness

BACKGROUND

Congenital cytomegalovirus (CMV) infection is the leading cause of non-genetic congenital hearing loss. The contribution of congenital CMV to prelingual deafness and the pathophysiology is largely unknown.

OBJECTIVE

(1) To analyze the prevalence of congenital CMV among cochlear implant (CI) recipients with prelingual deafness. (2) To genotype CMV present in dried blood spots (DBS) and in the inner ear years after birth.

STUDY DESIGN

Children and adults with prelingual deafness who received a CI in 2010-2011 were included prospectively. Perilymphatic fluids were collected during CI surgery and, in the pediatric cases, DBS were retrieved for CMV DNA detection. Furthermore, a cohort of children with prelingual deafness who received a CI between 2003 and 2008 were included retrospectively. CMV detection in DBS and perilymph was followed by gB and gH genotyping.

RESULTS

Seventysix pediatric CI recipients were included. Seventy DBS were tested for CMV DNA, resulting in a prevalence of congenital CMV of 14% (10/70). Perilymphatic fluid was available from 29 pediatric CI recipients. One perilymph fluid, of a 21-month old girl with congenital CMV, asymptomatic at birth, was CMV DNA positive. The CMV strain in the perilymph was genotypically identical to the strain present in her DBS (gB1/gH2). Perilymph samples from 21 adult CI recipients were CMV DNA negative.

CONCLUSIONS

Our study stresses the important contribution of congenital CMV among pediatric CI recipients. Furthermore, our genotyping data support the hypothesis that CMV-related hearing loss is associated with ongoing viral replication in the inner ear up to years after birth.

Identification of a varicella-zoster virus replication inhibitor that blocks capsid assembly by interacting with the floor domain of the major capsid protein

A novel anti-varicella-zoster virus compound, a derivative of pyrazolo[1,5-c]1,3,5-triazin-4-one (coded as 35B2), was identified from a library of 9,600 random compounds. This compound inhibited both acyclovir (ACV)-resistant and -sensitive strains. In a plaque reduction assay under conditions in which the 50% effective concentration of ACV against the vaccine Oka strain (V-Oka) in human fibroblasts was 4.25 μM, the 50% effective concentration of 35B2 was 0.75 μM. The selective index of the compound was more than 200. Treatment with 35B2 inhibited neither immediate-early gene expression nor viral DNA synthesis. Twenty-four virus clones resistant to 35B2 were isolated, all of which had a mutation(s) in the amino acid sequence of open reading frame 40 (ORF40), which encodes the major capsid protein (MCP). Most of the mutations were located in the regions corresponding to the "floor" domain of the MCP of herpes simplex virus 1. Treatment with 35B2 changed the localization of MCP in the fibroblasts infected with V-Oka but not in the fibroblasts infected with the resistant clones, although it did not affect steady-state levels of MCP. Overexpression of the scaffold proteins restored the normal MCP localization in the 35B2-treated infected cells. The compound did not inhibit the scaffold protein-mediated translocation of MCP from the cytoplasm to the nucleus. Electron microscopic analysis demonstrated the lack of capsid formation in the 35B2-treated infected cells. These data indicate the feasibility of developing a new class of antivirals that target the herpesvirus MCPs and inhibit normal capsid formation by a mechanism that differs from those of the known protease and encapsidation inhibitors. Further biochemical studies are required to clarify the precise antiviral mechanism.

Outcome of cochlear implantation in children with congenital cytomegalovirus infection or GJB2 mutation

CONCLUSIONS

Outcomes following cochlear implantation in children with congenital cytomegalovirus (CMV) infection were almost equivalent to those of children with GJB2 mutation-related sensorineural hearing loss (SNHL). Although our patients with developmental disorder showed poor auditory performance and speech and language skills after cochlear implantation, SNHL with developmental disorder should not be a contraindication for the procedure.

OBJECTIVE

Congenital CMV infection accounts for approximately 20% of all cases of neonatal hearing loss, while the GJB2 mutation accounts for 30-50% of all cases of profound nonsyndromic hearing loss. Here, outcomes for auditory behavior and speech and language skills were compared in children with congenital CMV infection or GJB2 mutation who received cochlear implantation for profound SNHL.

METHODS

Five children with asymptomatic congenital CMV infection and seven children with GJB2 mutation-related SNHL, with and without developmental disorder, underwent cochlear implantation. Hearing level and speech and language development were evaluated post-implantation using IT-MAIS, MUSS, and S-S method.

RESULTS

The IT-MAIS and MUSS scores of the congenital CMV infection group and the GJB2 mutation group continued to increase for 4 years after implantation. The S-S method score in both groups gradually increased, although the scores for children with mental retardation were low.