Congenital Cytomegalovirus and HIV Perinatal Transmission

The Pathogenesis of Cytomegalovirus and Other Viruses Associated with Hearing Loss: Recent Updates

Virus infection is one of the most common etiologies of hearing loss. Hearing loss associated with viral infection can be unilateral or bilateral, mild or severe, sudden or progressive, and permanent or recoverable. Many viruses cause hearing loss in adults and children; however, the pathogenesis of hearing loss caused by viral infection is not fully understood. This review describes cytomegalovirus, the most common virus causing hearing loss, and other reported hearing loss-related viruses. We hope to provide a detailed description of pathogenic characteristics and research progress on pathology, hearing phenotypes, possible associated mechanisms, treatment, and prevention measures. This review aims to provide diagnostic and treatment assistance to clinical workers.

Sustained Virologic Suppression Reduces HIV-1 DNA Proviral Levels and HIV Antibodies in Perinatally HIV-Infected Children Followed from Birth

The extent to which perinatally HIV-infected children, following cART initiation, develop a low proviral reservoir burden over time, as measured by HIV DNA droplet-digital polymerase chain reaction (ddPCR) and the effect on HIV antibody is not well characterized. We measured proviral HIV DNA and plasma RNA virus load (VL) in 37 perinatally HIV-infected children at 6 months of age who initiated stable cART. At 6-11 years of age, HIV proviral DNA, HIV VL (RNA), and HIV antibody by Western Blot (WB) were assessed. CART was initiated before 6 months of age in 13 children and after 6 months in 24. At school age, the HIV DNA levels did not differ by the timing of cART, and the HIV DNA levels were lower in children with negative/indeterminate WB (p = 0.0256). Children with undetectable HIV RNA VL > 50% of the time since cART initiation had lower median DNA VL than children with undetectable VL < 50% of the time (p = 0.07). Long-term viral suppression in perinatally HIV-infected children is associated with a decrease in HIV antibodies and reduced HIV reservoirs.

Cortical structural changes related to early antiretroviral therapy (ART) interruption in perinatally HIV-infected children at 5 years of age

ART interruption in children can occur especially in resource-limited settings for reasons including poor adherence, stock-outs, ART intolerance of non-pediatric formulas and pill size, as well as ultimately to test for HIV remission. Although early ART initiation is now standard of care in pediatric HIV management, very little is known on the effect of early ART initiation or subsequent interruption on brain development. This study aimed to investigate the effect of ART interruption on brain cortical thickness (CT) and folding in a subset of children from the Children with HIV Early antiRetroviral therapy (CHER) trial cohort who all started ART before 18 months of age. CHER participants in the neuroimaging follow-up study had magnetic resonance (MRI) scans on a 3T Siemens Allegra brain scanner at age 5.44 ± 0.37 years. MR images were processed using the automated cross-sectional stream in FreeSurfer v6.0 and vertex wise comparisons of CT and local gyrification indices (LGIs) were performed between HIV+ children and HIV- controls, as well as between HIV+ children on interrupted or continuous ART and controls. HIV+ children (n = 46) showed thicker cortex than HIV- children (n = 29) in bilateral frontal and left temporo-insular regions but lower LGIs in left superior and bilateral medial orbitofrontal cortex extending into rostral anterior cingulate. Children on interrupted ART (n = 21) had thicker cortex than HIV- controls in left frontal and right insular regions, but children on continuous treatment (n = 25) showed no difference from controls. Children on both interrupted and continuous ART showed region-specific alterations in LGI relative to controls. Cortical folding appears more sensitive than CT to early life events including early ART and interruption. However, immune health resilience in children can translate to long term preservation of morphometric brain development, especially for those on early and continuous treatment.

Placental Immune Responses to Viruses: Molecular and Histo-Pathologic Perspectives

As most recently demonstrated by the SARS-CoV-2 pandemic, congenital and perinatal infections are of significant concern to the pregnant population as compared to the general population. These outcomes can range from no apparent impact all the way to spontaneous abortion or fetal infection with long term developmental consequences. While some pathogens have developed mechanisms to cross the placenta and directly infect the fetus, other pathogens lead to an upregulation in maternal or placental inflammation that can indirectly cause harm. The placenta is a temporary, yet critical organ that serves multiple important functions during gestation including facilitation of fetal nutrition, oxygenation, and prevention of fetal infection in utero. Here, we review trophoblast cell immunology and the molecular mechanisms utilized to protect the fetus from infection. Lastly, we discuss consequences in the placenta when these protections fail and the histopathologic result following infection.

Role of antenatal plasma cytomegalovirus DNA levels on pregnancy outcome and HIV-1 vertical transmission among mothers in the University of Zimbabwe birth cohort study (UZBCS)

INTRODUCTION

Despite being a leading infectious cause of childhood disability globally, testing for cytomegalovirus (CMV) infections in pregnancy is generally not done in Sub-Sahara Africa (SSA), where breastfeeding practice is almost universal. Whilst CMV and human immunodeficiency virus (HIV) are both endemic in SSA, the relationship between antenatal plasma CMV-DNA, HIV-1-RNA levels and HIV-1-mother to child transmission (MTCT) including pregnancy outcomes remains poorly described.

METHODS

Pregnant women at least 20 weeks' gestational age at enrolment were recruited from relatively poor high-density suburbs in Harare, Zimbabwe. Mother-infant dyads were followed up until 6 months postpartum. In a case-control study design, we tested antenatal plasma CMV-DNA levels in all 11 HIV-1 transmitting mothers, as well as randomly selected HIV-infected but non-transmitting mothers and HIV-uninfected controls. CMV-DNA was detected and quantified using polymerase chain reaction (PCR) technique. Antenatal plasma HIV-1-RNA load was quantified by reverse transcriptase PCR. Infants' HIV-1 infection was detected using qualitative proviral DNA-PCR. Predictive value of antenatal plasma CMV-DNAemia (CMV-DNA of > 50 copies/mL) for HIV-1-MTCT was analyzed in univariate and multivariate regression analyses. Associations of CMV-DNAemia with HIV-1-RNA levels and pregnancy outcomes were also explored.

RESULTS

CMV-DNAemia data were available for 11 HIV-1 transmitting mothers, 120 HIV-infected but non-transmitting controls and 46 HIV-uninfected mothers. In a multivariate logistic regression model, we found a significant association between CMV-DNAemia of > 50 copies/mL and HIV-1 vertical transmission (p = 0.035). There was no difference in frequencies of detectable CMV-DNAemia between HIV-infected and -uninfected pregnant women (p = 0.841). However, CMV-DNA levels were higher in immunosuppressed HIV-infected pregnant women, CD4 < 200 cells/µL (p = 0.018). Non-significant associations of more preterm births (< 37 weeks, p = 0.063), and generally lower birth weights (< 2500 g, p = 0.450) were observed in infants born of HIV-infected mothers with CMV-DNAemia. Furthermore, in a multivariate analysis of HIV-infected but non-transmitting mothers, CMV-DNAemia of > 50 copies/mL correlated significantly with antenatal plasma HIV-1-RNA load (p = 0.002).

CONCLUSION

Antenatal plasma CMV-DNA of > 50 copies/mL may be an independent risk factor for HIV-1-MTCT and higher plasma HIV-1-RNA load, raising the possibility that controlling antenatal CMV-DNAemia might improve infant health outcomes. Further studies with larger sample sizes are warranted to confirm our findings.

Overview of Human Cytomegalovirus Pathogenesis

Human cytomegalovirus (HCMV) is a betaherpesvirus with a global seroprevalence of 60-90%. HCMV is the leading cause of congenital infections and poses a great health risk to immunocompromised individuals. Although HCMV infection is typically asymptomatic in the immunocompetent population, infection can result in mononucleosis and has also been associated with the development of certain cancers, as well as chronic inflammatory diseases such as various cardiovascular diseases. In immunocompromised patients, including AIDS patients, transplant recipients, and developing fetuses, HCMV infection is associated with increased rates of morbidity and mortality. Currently there is no vaccine for HCMV and there is a need for new pharmacological treatments. Ongoing research seeks to further define the complex aspects of HCMV pathogenesis, which could potentially lead to the generation of new therapeutics to mitigate the disease states associated with HCMV infection. The following chapter reviews the advancements in our understanding of HCMV pathogenesis in the immunocompetent and immunocompromised hosts.

Recent Approaches and Strategies in the Generation of Anti-human Cytomegalovirus Vaccines

Human cytomegalovirus is the largest human herpesvirus and shares many core features of other herpesviruses such as tightly regulated gene expression during genome replication and latency as well as the establishment of lifelong persistence following infection. In contrast to stereotypic clinical syndromes associated with alpha-herpesvirus infections, almost all primary HCMV infections are asymptomatic and acquired early in life in most populations in the world. Although asymptomatic in most individuals, HCMV is a major cause of disease in hosts with deficits in adaptive and innate immunity such as infants who are infected in utero and allograft recipients following transplantation. Congenital HCMV is a commonly acquired infection in the developing fetus that can result in a number of neurodevelopmental abnormalities. Similarly, HCMV is a major cause of disease in allograft recipients in the immediate and late posttransplant period and is thought to be a major contributor to chronic allograft rejection. Even though HCMV induces robust innate and adaptive immune responses, it also encodes a vast array of immune evasion functions that are thought aid in its persistence. Immune correlates of protective immunity that prevent or modify intrauterine HCMV infection remain incompletely defined but are thought to consist primarily of adaptive responses in the pregnant mother, thus making congenital HCMV a potentially vaccine modifiable disease. Similarly, HCMV infection in allograft recipients is often more severe in recipients without preexisting adaptive immunity to HCMV. Thus, there has been a considerable effort to modify HCMV specific immunity in transplant recipient either through active immunization or passive transfer of adaptive effector functions. Although efforts to develop an efficacious vaccine and/or passive immunotherapy to limit HCMV disease have been underway for nearly six decades, most have met with limited success at best. In contrast to previous efforts, current HCMV vaccine development has relied on observations of unique properties of HCMV in hopes of reproducing immune responses that at a minimum will be similar to that following natural infection. However, more recent findings have suggested that immunity following naturally acquired HCMV infection may have limited protective activity and almost certainly, is not sterilizing. Such observations suggest that either the induction of natural immunity must be specifically tailored to generate protective activity or alternatively, that providing targeted passive immunity to susceptible populations could be prove to be more efficacious.

Congenital Cytomegalovirus and Human Immunodeficiency Virus: Effects on Hearing, Speech and Language Development, and Clinical Outcomes in Children

Prenatal infections can have adverse effects on an infant's hearing, speech, and language development. Congenital cytomegalovirus (CMV) and human immunodeficiency virus (HIV) are two such infections that may lead to these complications, especially when left untreated. CMV is commonly associated with sensorineural hearing loss in children, and it can also be associated with anatomical abnormalities in the central nervous system responsible for speech, language, and intellectual acquisition. In terms of speech, language, and hearing, HIV is most associated with conductive and/or sensorineural hearing loss and expressive language deficits. Children born with these infections may benefit from cochlear implantation for severe to profound sensorineural hearing losses and/or speech therapy for speech/language deficits. CMV and HIV simultaneously present in infants has not been thoroughly studied, but one may hypothesize these speech, language, and hearing deficits to be present with potentially higher severity. Early identification of the infection in combination with early intervention strategies yields better results for these children than no identification or intervention. The purpose of this review was to investigate how congenital CMV and/or HIV may affect hearing, speech, and language development in children, and the importance of early identification for these populations.

Humoral Immune Correlates for Prevention of Postnatal Cytomegalovirus Acquisition

BACKGROUND

Development of a cytomegalovirus (CMV) vaccine is a high priority. However, the ability of antibodies to protect against CMV infection is not well characterized. Studies of maternal antibodies in infants offer the potential to identify humoral correlates of protection against postnatal acquisition.

METHODS

This hypothesis-generating study analyzed 29 Ugandan mother-infant pairs that were followed weekly for CMV acquisition. Seventeen mothers and no infants were infected with human immunodeficiency virus (HIV). We evaluated the association between CMV-specific immunoglobulin G (IgG) responses in mothers at the time of delivery and their infants' CMV status at 6 months of age. We also assessed levels of CMV-specific IgG in infants at 6 weeks of age. CMV-specific IgG responses in the mother-infant pairs were then analyzed on the basis of perinatal HIV exposure.

RESULTS

We found similar levels of multiple CMV glycoprotein-specific IgG binding specificities and functions in mothers and infants, irrespective of perinatal HIV exposure or infant CMV status at 6 months of age. However, the glycoprotein B-specific IgG titer, measured by 2 distinct assays, was higher in infants without CMV infection and was moderately associated with delayed CMV acquisition.

CONCLUSIONS

These data suggest that high levels of glycoprotein B-specific IgG may contribute to the partial protection against postnatal CMV infection afforded by maternal antibodies, and they support the continued inclusion of glycoprotein B antigens in CMV vaccine candidates.

Estimating the Risk of Human Herpesvirus 6 and Cytomegalovirus Transmission to Ugandan Infants from Viral Shedding in Saliva by Household Contacts

Human herpesvirus 6 (HHV-6) and cytomegalovirus (CMV) infections are common in early childhood. In a prospective Ugandan birth cohort study, most infants acquired HHV-6 (24/31; 77%) and CMV (20/30; 67%) during follow-up. To assess the transmission risk, we modeled a dose-response relationship between infant HHV-6 and CMV infections and weekly oral viral shedding by mothers and all other ("secondary") children in the home. Oral viral loads that were shed by mothers and secondary children were significantly associated with HHV-6 but not CMV transmission. While secondary children had higher and more frequent HHV-6 shedding than their mothers, they had a lower per-exposure transmission risk, suggesting that transmission to maternal contacts may be more efficient. HHV-6 transmission was relatively inefficient, occurring after <25% of all weekly exposures. Although HHV-6 transmission often occurs following repeated, low dose exposures, we found a non-linear dose-response relationship in which infection risk markedly increases when exposures reached a threshold of > 5 log₁₀ DNA copies/mL. The lack of association between oral CMV shedding and transmission is consistent with breastfeeding being the dominant route of infant infection for that virus. These affirm saliva as the route of HHV-6 transmission and provide benchmarks for developing strategies to reduce the risk of infection and its related morbidity.

Opportunistic Infections

Evolution in paediatric HIV management has changed the incidence and prevalence of opportunistic infections and a major reduction has been shown for most opportunistic infections with antiretroviral therapy use in lower and middle-income countries, especially in the first year of treatment. However, the high prevalence of disease still requires adequate management of opportunistic infections, to improve patient quality of life and the impact on burden of disease. Lower CD4 counts were associated with chronic infection and increased risk of opportunistic infections in patients, but some studies have shown that even children with high CD4 counts may have opportunistic infections.

This chapter reviews common opportunistic infections that may infect HIV positive children and adolescents, particularly in sub Saharan Africa.

The impact of maternal HIV and malaria infection on the prevalence of congenital cytomegalovirus infection in Western Kenya

BACKGROUND

Data on congenital cytomegalovirus (CMV) infection in Africa are limited.

OBJECTIVE

To describe the prevalence of congenital CMV infection in a population with high prevalence of maternal HIV and malaria infection in western Kenya.

STUDY DESIGN

We screened newborns for CMV by polymerase chain reaction assay of saliva swabs and dried blood spots (DBS), and assessed maternal CMV immunoglobulin G (IgG) status by testing serum eluted from newborn's DBS. We calculated adjusted prevalence ratios (aPRs) using log-binomial regression models.

RESULTS

Among 1066 mothers, 210 (19·7%) had HIV infection and 207 (19·4%) had malaria infection; 33 (3·1%) mothers had both. Maternal CMV IgG prevalence was 93·1% (95% confidence interval [CI]: 88·3%-96·0%). Among 1078 newborns (12 sets of twins), 39 (3·6%, 95% CI: 2·7-4·9%) were CMV positive. The prevalence of congenital CMV infection by maternal HIV and malaria infection status was 5·0% (95% CI: 2·7-9·2%) for HIV only, 5·1% (95% CI: 2·7-9·4%) for malaria only, 8·8 (95% CI: 3·1-23·0) for HIV and malaria co-infection, and 2·6% (95% CI: 1·7-4·1%) for none. Congenital CMV infection was independently associated with maternal HIV infection (aPR=2·1; 95% CI: 1·0-4·2), adjusting for maternal age, parity, and malaria infection.

CONCLUSIONS

The prevalence of congenital CMV infection was higher than the 0·2-0·7% in developed countries. Maternal HIV infection may increase the risk of congenital CMV infection, but the role of maternal malaria on intrauterine transmission of CMV remains unclear.

Advances in pediatrics in 2017: current practices and challenges in allergy, endocrinology, gastroenterology, genetics, immunology, infectious diseases, neonatology, nephrology, neurology, pulmonology from the perspective of Italian Journal of Pediatrics

This review provides an overview of a remarkable number of significant studies in pediatrics that have been published over the past year in the Italian Journal of Pediatrics. We have selected information from papers presented in the Journal that deal with allergy, endocrinology, gastroenterology, genetics, immunology, infectious diseases, neonatology, nephrology, neurology, pulmonology. The relevant epidemiologic findings, and developments in prevention, diagnosis and treatment of the last year have been discussed and placed in context. We think that advances achieved in 2017 will help readers to make the future of patients better.