Acute cytomegalovirus infection in Kenyan HIV-infected infants

Clinical and Immunologic Impact of CMV Coinfection Among Children Living With HIV in Canada

BACKGROUND

Although cytomegalovirus (CMV) disease has been well described among severely immunocompromised children living with HIV (CLWH), the impact of CMV coinfection, is not well understood. The objective of this study was to characterize the clinical and immunologic effects of CMV coinfection in CLWH in Canada.

METHODS

This is a substudy of the Early Pediatric Initiation, Canada Child Cure Cohort study, which enrolled CLWH in Canada between 2014 and 2018. CMV serostatus was determined at the first (baseline) study visit, and HIV-1 viral load (VL), CMV VL, and lymphocyte subsets were quantified every 3-6 months. For a subset of participants, CD4+ and CD8+ T cell subsets were analyzed using flow cytometry. The clinical outcomes were recorded retrospectively at the baseline visit and prospectively during the study period.

RESULTS

Of the 225 participants, 85.3% were CMV seropositive (CMV+) and 81% had suppressed HIV VL. While there were no significant differences in clinical outcomes between CMV+ and CMV- children, CMV+ children had lower frequencies of CD4+ T cells, higher frequencies of CD8+ T cells, and lower CD4/CD8 ratio at baseline than CMV- children. Children with CMV+ children also demonstrated a higher frequency of CD4+ effector memory cells, lower CD8+ naïve T cells, and higher frequencies of CD8+ terminally differentiated effector memory cells. These differences remained significant even after adjusting for HIV viral control.

CONCLUSIONS

CMV coinfection is common among CLWH and is associated with distinct immunological changes despite the effective control of HIV replication with antiretroviral therapy. The long-term implications of these immunological perturbations require further investigation.

Distinct immune profiles in children living with HIV based on timing and duration of suppressive antiretroviral treatment

Timely initiation of antiretroviral therapy (ART) remains a major challenge in the effort to treat children living with HIV ("CLH") and little is known regarding the dynamics of immune normalization following ART in CLH with varying times to and durations of ART. Here, we leveraged two cohorts of virally-suppressed CLH from Nairobi, Kenya to examine differences in the peripheral immune systems between two cohorts of age-matched children (to control for immune changes with age): one group which initiated ART during early HIV infection and had been on ART for 5-6 years at evaluation (early, long-term treated; "ELT" cohort), and one group which initiated ART later and had been on ART for approximately 9 months at evaluation (delayed, short-term treated; "DST" cohort). We profiled PBMC and purified NK cells from these two cohorts by mass cytometry time-of-flight (CyTOF). Although both groups of CLH had undetectable viral RNA load at evaluation, there were marked differences in both immune composition and immune phenotype between the ELT cohort and the DST cohort. DST donors had reduced CD4 T cell percentages, decreased naive to effector memory T cell ratios, and markedly higher expression of stress-induced markers. Conversely, ELT donors had higher naive to effector memory T cell ratios, low expression of stress-induced markers, and increased expression of markers associated with an effective antiviral response and resolution of inflammation. Collectively, our results demonstrate key differences in the immune systems of virally-suppressed CLH with different ages at ART initiation and durations of treatment and provide further rationale for emphasizing early onset of ART.

Association between HIV and cytomegalovirus and neurocognitive outcomes among children with HIV

OBJECTIVES

Children with HIV may experience adverse neurocognitive outcomes despite antiretroviral therapy (ART). Cytomegalovirus (CMV) is common in children with HIV. Among children on ART, we examined the influences of early HIV viral load and CMV DNA on neurocognition.

DESIGN

We determined the association between pre-ART viral load, cumulative viral load, and CMV viremia and neurocognition using data from a cohort study.

METHODS

Children who initiated ART before 12 months of age were enrolled from 2007 to 2010 in Nairobi, Kenya. Blood was collected at enrollment and every 6 months thereafter. Four neurocognitive assessments with 12 domains were conducted when children were a median age of 7 years. Primary outcomes included cognitive ability, executive function, attention, and motor z scores. Generalized linear models were used to determine associations between HIV viral load (pre-ART and cumulative; N  = 38) and peak CMV DNA (by 24 months of age; N  = 20) and neurocognitive outcomes.

RESULTS

In adjusted models, higher peak CMV viremia by 24 months of age was associated with lower cognitive ability and motor z scores. Higher pre-ART HIV viral load was associated with lower executive function z scores. Among secondary outcomes, higher pre-ART viral load was associated with lower mean nonverbal and metacognition z scores.

CONCLUSION

Higher pre-ART viral load and CMV DNA in infancy were associated with lower executive function, nonverbal and metacognition scores and cognitive ability and motor scores in childhood, respectively. These findings suggest long-term benefits of early HIV viral suppression and CMV control on neurocognition.

"Congenital cytomegalovirus in Sub-Saharan Africa-a narrative review with practice recommendations"

Cytomegalovirus (CMV) is the most common cause of congenital infection internationally, occurring in 0.67% of births, and increasingly recognised as a major public health burden due to the potential for long-term neurodevelopmental and hearing impairment. This burden includes estimates of 10% of childhood cerebral palsy and up to 25% of childhood deafness. In Sub-Saharan Africa, where CMV-seroprevalence is almost ubiquitous, prevalence of congenital CMV (cCMV) is higher than the global average, and yet there is a dearth of research and initiatives to improve recognition, diagnosis and treatment. This narrative review outlines the epidemiology and clinical presentation of cCMV, discusses issues of case identification and treatment in Sub-Saharan Africa, and recommends a framework of strategies to address these challenges. Considering the significant burden of cCMV disease in this setting, it is undoubtably time we embark upon improving diagnosis and care for these infants.

Human Cytomegalovirus Immunoglobulin G Response and Pulmonary Tuberculosis in Adolescents: A Case-Control Study

Background

Emerging evidence suggests a link between infection with herpes viruses, particularly human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV), and progression to tuberculosis disease.

Methods

An unmatched case-control study was conducted among adolescents aged 10-19 years enrolled in an observational study (Teen TB) between November 2020 and November 2021, in Cape Town, South Africa. Fifty individuals with pulmonary tuberculosis and 51 healthy tuberculosis-exposed individuals without tuberculosis were included. Demographics and clinical data were obtained, and serum samples collected at enrolment were tested for HCMV immunoglobulin G (IgG) and EBV nuclear antigen (EBNA) IgG using 2 automated enzyme immunoassays. Odds ratios were estimated using unconditional logistic regression.

Results

The median age of 101 participants was 15 years (interquartile range, 13-17 years); 55 (54%) were female. All participants were HCMV IgG seropositive, and 95% were EBNA IgG seropositive. Individuals with tuberculosis had higher HCMV IgG titers than healthy controls (P = .04). Individuals with upper-tertile HCMV IgG titers had 3.67 times greater odds of pulmonary tuberculosis than those with IgG titers in the lower tertile (95% confidence interval, 1.05-12.84; P = .04). There was a trend for increasing odds of pulmonary tuberculosis with increasing titers of HCMV IgG (P = .04). In contrast, there was no association between tuberculosis and higher EBNA IgG values.

Conclusions

There is a high prevalence of sensitization to HCMV and EBV among adolescents in this high-tuberculosis-burden setting. Higher HCMV IgG titers were associated with pulmonary tuberculosis in adolescents.

Molecular Pathogenesis of Human Immunodeficiency Virus-Associated Disease of Oropharyngeal Mucosal Epithelium

The oropharyngeal mucosal epithelia have a polarized organization, which is critical for maintaining a highly efficient barrier as well as innate immune functions. In human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) disease, the barrier and innate immune functions of the oral mucosa are impaired via a number of mechanisms. The goal of this review was to discuss the molecular mechanisms of HIV/AIDS-associated changes in the oropharyngeal mucosa and their role in promoting HIV transmission and disease pathogenesis, notably the development of opportunistic infections, including human cytomegalovirus, herpes simplex virus, and Epstein-Barr virus. In addition, the significance of adult and newborn/infant oral mucosa in HIV resistance and transmission was analyzed. HIV/AIDS-associated changes in the oropharyngeal mucosal epithelium and their role in promoting human papillomavirus-positive and negative neoplastic malignancy are also discussed.

Predictors of intact HIV DNA levels among children in Kenya

OBJECTIVE

We determined predictors of both intact (estimate of replication-competent) and total (intact and defective) HIV DNA in the reservoir among children with HIV.

DESIGN

HIV DNA in the reservoir was quantified longitudinally in children who initiated antiretroviral therapy (ART) at less than 1 year of age using a novel cross-subtype intact proviral DNA assay that measures both intact and total proviruses. Quantitative PCR was used to measure pre-ART cytomegalovirus (CMV) viral load. Linear mixed effects models were used to determine predictors of intact and total HIV DNA levels (log 10 copies/million).

RESULTS

Among 65 children, median age at ART initiation was 5 months and median follow-up was 5.2 years; 86% of children had CMV viremia pre-ART. Lower pre-ART CD4 + percentage [adjusted relative risk (aRR): 0.87, 95% confidence intervals (95% CI): 0.79-0.97; P  = 0.009] and higher HIV RNA (aRR: 1.21, 95% CI: 1.06-1.39; P  = 0.004) predicted higher levels of total HIV DNA during ART. Pre-ART CD4 + percentage (aRR: 0.76, 95% CI: 0.65-0.89; P < 0.001), CMV viral load (aRR: 1.16, 95% CI: 1.01-1.34; P  = 0.041), and first-line protease inhibitor-based regimens compared with nonnucleoside reverse transcriptase-based regimens (aRR: 1.36, 95% CI: 1.04-1.77; P  = 0.025) predicted higher levels of intact HIV DNA.

CONCLUSION

Pre-ART immunosuppression, first-line ART regimen, and CMV viral load may influence establishment and sustainment of intact HIV DNA in the reservoir.

Inflammation and immune activation are associated with risk of Mycobacterium tuberculosis infection in BCG-vaccinated infants

Tuberculosis vaccine development is hindered by the lack of validated immune correlates of protection. Exploring immune correlates of risk of disease and/or infection in prospective samples can inform this field. We investigate whether previously identified immune correlates of risk of TB disease also associate with increased risk of M.tb infection in BCG-vaccinated South African infants, who became infected with M.tb during 2-3 years of follow-up. M.tb infection is defined by conversion to positive reactivity in the QuantiFERON test. We demonstrate that inflammation and immune activation are associated with risk of M.tb infection. Ag85A-specific IgG is elevated in infants that were subsequently infected with M.tb, and this is coupled with upregulated gene expression of immunoglobulin-associated genes and type-I interferon. Plasma levels of IFN-[Formula: see text]2, TNF-[Formula: see text], CXCL10 (IP-10) and complement C2 are also higher in infants that were subsequently infected with M.tb.

Cytomegalovirus Viremia Predicts Postdischarge Mortality in Kenyan HIV-Exposed Uninfected Children

BACKGROUND

Cytomegalovirus (CMV) viremia is associated with mortality in severely ill immunocompetent adults and hospitalized children with HIV (CWH). We measured CMV viremia in HIV-exposed and -unexposed Kenyan children aged 1-59 months discharged from hospital and determined its relationship with postdischarge mortality.

METHODS

CMV DNA levels were measured in plasma from 1024 children (97 of which were HIV exposed uninfected [HEU], and 15 CWH). Poisson and Cox proportional hazards regression models were used to identify correlates of CMV viremia ≥ 1000 IU/mL 
and estimate associations with 6-month mortality, respectively.

RESULTS

CMV viremia was detected in 31% of children, with levels ≥ 1000 IU/mL in 5.8%. HIV infection, age < 2 years, breastfeeding, and midupper arm circumference < 12.5 cm were associated with CMV viremia ≥ 1000 IU/mL. Among HEU children, CMV ≥ 1000 IU/mL (hazard ratio [HR] = 32.0; 95% confidence interval [CI], 2.9-354.0; P = .005) and each 1-log increase in CMV viral load (HR = 5.04; 95% CI, 1.7-14.6; P = .003) were associated with increased risk of mortality. CMV viremia was not significantly associated with mortality in HIV-unexposed children.

CONCLUSIONS

CMV levels at hospital postdischarge predict increased risk of 6-month mortality in Kenyan HEU children. CMV suppression may be a novel target to reduce mortality in HEU children.

CLINICAL TRIAL REGISTRATION

NCT02414399.

Cytomegalovirus Viremia and Clinical Outcomes in Kenyan Children Diagnosed With Human Immunodeficiency Virus (HIV) in Hospital

BACKGROUND

Cytomegalovirus (CMV) viremia is common in human immunodeficiency virus (HIV) infection and is associated with worse long-term outcomes. To date, no studies have assessed CMV viremia in children diagnosed with HIV in hospital.

METHODS

We studied CMV viremia and clinical outcomes in 163 Kenyan children aged 2 months to 12 years, diagnosed with HIV in hospital. CMV DNA levels in plasma were measured using quantitative polymerase chain reaction (PCR). Regression models were used to assess associations between CMV viremia ≥1000 IU/mL and the risk of continued hospitalization or death at 15 days, duration of hospitalization, and 6-month mortality.

RESULTS

At enrollment, 62/114 (54%) children had CMV viremia, and 20 (32%) were ≥1000 IU/mL. Eleven CMV reactivations were observed after admission. The prevalence and level of CMV viremia were highest in children <2 years and lowest in children ≥5 years old. CMV viremia ≥1000 IU/mL was independently associated with age <2 years (P = .03), higher log10 HIV RNA level (P = .01), and height-for-age z score >-2 (P = .02). Adjusting for age and log10 HIV RNA, the relative risk of death or continued hospitalization at 15 days was 1.74 (95% confidence interval [CI] = 1.04, 2.90), and the hazard ratio of 6-month mortality was 1.97 (95% CI = .57, 5.07) for children with CMV DNA ≥1000 IU/mL compared to lower-level or undetectable CMV DNA. Children with CMV DNA ≥1000 IU/mL were hospitalized a median ~5 days longer than children with lower-level or undetectable CMV DNA (P = .002).

CONCLUSIONS

In this nested observational study, CMV viremia was common in hospitalized children with HIV, and levels ≥1000 IU/mL were associated with increased risk of mortality and longer hospitalization.

Human Immunodeficiency Virus (HIV) and Human Cytomegalovirus (HCMV) Coinfection of Infant Tonsil Epithelium May Synergistically Promote both HIV-1 and HCMV Spread and Infection

Mother-to-child transmission (MTCT) of human immunodeficiency virus type 1 (HIV-1) and human cytomegalovirus (HCMV) may occur during pregnancy, labor, or breastfeeding. These viruses from amniotic fluid, cervicovaginal secretions, and breast milk may simultaneously interact with oropharyngeal and tonsil epithelia; however, the molecular mechanism of HIV-1 and HCMV cotransmission through the oral mucosa and its role in MTCT are poorly understood. To study the molecular mechanism of HIV-1 and HCMV MTCT via oral epithelium, we established polarized infant tonsil epithelial cells and polarized-oriented ex vivo tonsil tissue explants. Using these models, we showed that cell-free HIV-1 and its proteins gp120 and tat induce the disruption of tonsil epithelial tight junctions and increase paracellular permeability, which facilitates HCMV spread within the tonsil mucosa. Inhibition of HIV-1 gp120-induced upregulation of mitogen-activated protein kinase (MAPK) and NF-κB signaling in tonsil epithelial cells, reduces HCMV infection, indicating that HIV-1-activated MAPK and NF-κB signaling may play a critical role in HCMV infection of tonsil epithelium. HCMV infection of tonsil epithelial cells also leads to the disruption of tight junctions and increases paracellular permeability, facilitating HIV-1 paracellular spread into tonsil mucosa. HCMV-promoted paracellular spread of HIV-1 increases its accessibility to tonsil CD4 T lymphocytes, macrophages, and dendritic cells. HIV-1-enhanced HCMV paracellular spread and infection of epithelial cells subsequently leads to the spread of HCMV to tonsil macrophages and dendritic cells. Our findings revealed that HIV-1- and HCMV-induced disruption of infant tonsil epithelial tight junctions promotes MTCT of these viruses through tonsil mucosal epithelium, and therapeutic intervention for both HIV-1 and HCMV infection may substantially reduce their MTCT. IMPORTANCE Most HIV-1 and HCMV MTCT occurs in infancy, and the cotransmission of these viruses may occur via infant oropharyngeal and tonsil epithelia, which are the first biological barriers for viral pathogens. We have shown that HIV-1 and HCMV disrupt epithelial junctions, reducing the barrier functions of epithelia and thus allowing paracellular penetration of both viruses via mucosal epithelia. Subsequently, HCMV infects epithelial cells, macrophages, and dendritic cells, and HIV-1 infects CD4+ lymphocytes, macrophages, and dendritic cells. Infection of these cells in HCMV- and HIV-1-coinfected tonsil tissues is much higher than that by HCMV or HIV-1 infection alone, promoting their MTCT at its initial stages via infant oropharyngeal and tonsil epithelia.

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.

Association Between Cytomegalovirus and Epstein-Barr Virus Viremia And Human Immunodeficiency Virus DNA Levels in the Reservoir of Kenyan Infants Receiving Antiretroviral Therapy

Identifying determinants of human immunodeficiency virus (HIV) reservoir levels may inform novel viral eradication strategies. Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) coinfections were assessed as predictors of HIV proviral DNA level in 26 HIV RNA-suppressed Kenyan children starting antiretroviral therapy before 7 months of age. Earlier acquisition of CMV and EBV and higher cumulative burden of systemic EBV DNA viremia were each associated with higher HIV DNA level in the reservoir after 24 months of antiretroviral therapy, independent of HIV RNA levels over time. These data suggest that delaying or containing CMV and EBV viremia may be novel strategies to limit HIV reservoir formation.

Unexpectedly High Prevalence of Cytomegalovirus DNAemia in Older Children and Adolescents With Perinatally Acquired Human Immunodeficiency Virus Infection

Background

Older children and adolescents with perinatally acquired human immunodeficiency virus (PHIV) infection in Africa experience multiple comorbidities that are not typical of HIV-associated opportunistic infections, including growth impairment and chronic lung disease. We examined associations between plasma cytomegalovirus (CMV) DNA and lung function and growth.

Methods

Plasma CMV DNA loads were measured children aged 6–16 years with PHIV (n = 402) and HIV-uninfected controls (n = 224). The HIV-infected children were either newly diagnosed or known HIV infected and stable on antiretroviral therapy (ART) for >6 months. CMV DNA loads were measured using quantitative polymerase chain reaction. CMV DNAemia was modeled as a time-varying outcome using longitudinal mixed-effects logistic regression.

Results

At enrollment, CMV DNAemia ≥1000 copies/mL (defined as “clinically significant”) was detected in 5.8% of uninfected children, 14.7% of HIV-infected participants stable on ART, and 22.6% of HIV-infected ART-naive children (χ² = 23.8, P < .001). The prevalence of CMV DNAemia ≥1000 copies/mL was associated with CD4 counts <350 cells/µL. Among HIV-infected ART-naive children, the presence of CMV DNAemia of ≥1000 copies/mL was independently associated with reduced lung function (adjusted odds ratio [aOR] = 3.23; 95% confidence interval [CI], 1.23–8.46; P = .017). Among ART-treated children, stunting was associated with CMV DNAemia of ≥1000 copies/mL (aOR = 2.79; 95% CI, 0.97–8.02; P = .057).

Conclusions

Clinically significant levels of CMV DNAemia were common in older children with PHIV, even those on ART, suggesting a role for inadequately controlled CMV infection in the pathogenesis of PHIV comorbidities in Africa.

Cytomegalovirus infection is a risk factor for tuberculosis disease in infants

Immune activation is associated with increased risk of tuberculosis (TB) disease in infants. We performed a case-control analysis to identify drivers of immune activation and disease risk. Among 49 infants who developed TB disease over the first 2 years of life, and 129 healthy matched controls, we found the cytomegalovirus-stimulated (CMV-stimulated) IFN-γ response to be associated with CD8+ T cell activation (Spearman's rho, P = 6 × 10-8). A CMV-specific IFN-γ response was also associated with increased risk of developing TB disease (conditional logistic regression; P = 0.043; OR, 2.2; 95% CI, 1.02-4.83) and shorter time to TB diagnosis (Log Rank Mantel-Cox, P = 0.037). CMV+ infants who developed TB disease had lower expression of NK cell-associated gene signatures and a lower frequency of CD3-CD4-CD8- lymphocytes. We identified transcriptional signatures predictive of TB disease risk among CMV ELISpot-positive (area under the receiver operating characteristic [AUROC], 0.98, accuracy, 92.57%) and -negative (AUROC, 0.9; accuracy, 79.3%) infants; the CMV- signature was validated in an independent infant study (AUROC, 0.71; accuracy, 63.9%). A 16-gene signature that previously identified adolescents at risk of developing TB disease did not accurately classify case and control infants in this study. Understanding the microbial drivers of T cell activation, such as CMV, could guide new strategies for prevention of TB disease in infants.

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.

Early T Cell Differentiation with Well-Maintained Function across the Adult Life Course in Sub-Saharan Africa

Immune senescence is a significant contributor to health problems in the developed world and may be accelerated by chronic viral infections. To date, there have been few studies of immune function in healthy older people in sub-Saharan Africa. We assessed T cell and B cell phenotypes and immune responses to CMV, EBV, and influenza virus in Malawians aged 20-69 y. Notably, the proportion of naive (CCR7+CD45RA+) CD4 and CD8 T cells was only 14% of the lymphoid repertoire even in donors aged under 30 y but did not decrease further with age. A small increase in the late differentiated (CD27-CD28-) CD8 T cell subpopulation was observed in older donors but the CD4/CD8 T cell ratio remained stable in all age groups. Interestingly, the regulatory (CD25hiFOXP3hi) T cell subpopulation was small in all age groups, and we observed no age-associated accumulation of cells expressing the senescence- and exhaustion-associated markers CD57 and PD-1. We assessed functional T cell responses to mitogenic and viral antigenic stimulation by the expression of CD154, IFN-γ, TNF-α, IL-2, and IL-17 and proliferation. All responses were robust across the life course, although we observed an age-associated shift from IFN-γ to TNF-α in the response to EBV. In summary, we found the naive T cell subpopulation of young adult Malawians was smaller than in their contemporaries in high-income settings but remains stable thereafter and that lymphocyte function is retained across the life course. These observations indicate that studies of the genetic and environmental factors influencing immune function in different environments may provide insights into minimizing immune ageing.

Battle between Host Immune Cellular Responses and HCMV Immune Evasion

Human cytomegalovirus (HCMV) is ubiquitously prevalent. HCMV infection is typically asymptomatic and controlled by the immune system in healthy individuals, yet HCMV can be severely pathogenic for the fetus during pregnancy and in immunocompromised persons, such as transplant recipients or HIV infected patients. HCMV has co-evolved with the hosts, developed strategies to hide from immune effector cells and to successfully survive in the human organism. One strategy for evading or delaying the immune response is maintenance of the viral genome to establish the phase of latency. Furthermore, HCMV immune evasion involves the downregulation of human leukocyte antigens (HLA)-Ia molecules to hide infected cells from T-cell recognition. HCMV expresses several proteins that are described for downregulation of the HLA class I pathway via various mechanisms. Here, we review the wide range of immune evasion mechanisms of HCMV. Understanding the mechanisms of HCMV immune evasion will contribute to the development of new customized therapeutic strategies against the virus.

Congenital Cytomegalovirus and HIV Perinatal Transmission

BACKGROUND

Congenital cytomegalovirus (CMV) infection (cCMV) is an important cause of hearing loss and cognitive impairment. Prior studies suggest that HIV-exposed children are at higher risk of acquiring cCMV. We assessed the presence, magnitude and risk factors associated with cCMV among infants born to HIV-infected women, who were not receiving antiretrovirals during pregnancy.

METHODS

cCMV and urinary CMV load were determined in a cohort of infants born to HIV-infected women not receiving antiretrovirals during pregnancy. Neonatal urines obtained at birth were tested for CMV DNA by qualitative and reflex quantitative real-time polymerase chain reaction.

RESULTS

Urine specimens were available for 992 (58.9%) of 1684 infants; 64 (6.5%) were CMV-positive. Mean CMV load (VL) was 470,276 copies/ml (range: < 200-2,000,000 copies/ml). Among 89 HIV-infected infants, 16 (18%) had cCMV versus 42 (4.9%) of 858 HIV-exposed, uninfected infants (P < 0.0001). cCMV was present in 23.2% of infants with in utero and 9.1% infants with intrapartum HIV infection (P < 0.0001). Rates of cCMV among HIV-infected infants were 4-fold greater (adjusted OR, 4.4; 95% CI: 2.3-8.2) and 6-fold greater among HIV in utero-infected infants (adjusted OR, 6; 95% CI: 3-12.1) compared with HIV-exposed, uninfected infants. cCMV was not associated with mode of delivery, gestational age, Apgar scores, 6-month infant mortality, maternal age, race/ethnicity, HIV viral load or CD4 count. Primary cCMV risk factors included infant HIV-infection, particularly in utero infection.

CONCLUSION

High rates of cCMV with high urinary CMV VL were observed in HIV-exposed infants. In utero HIV infection appears to be a major risk factor for cCMV in infants whose mothers have not received combination antiretroviral therapy in pregnancy.

Temporal Improvements in Long-term Outcome in Care Among HIV-infected Children Enrolled in Public Antiretroviral Treatment Care: An Analysis of Outcomes From 2004 to 2012 in Zimbabwe

BACKGROUND

Increasing numbers of children are requiring long-term HIV care and antiretroviral treatment (ART) in public ART programs in Africa, but temporal trends and long-term outcomes in care remain poorly understood.

METHODS

We analyzed outcomes in a longitudinal cohort of infants (<2 years of age) and children (2-10 years of age) enrolling in a public tertiary ART center in Zimbabwe over an 8-year period (2004-2012).

RESULTS

The clinic enrolled 1644 infants and children; the median age at enrollment was 39 months (interquartile range: 14-79), with a median CD4% of 17.0 (interquartile range: 11-24) in infants and 15.0 (9%-23%) in children (P = 0.0007). Among those linked to care, 33.5% dropped out of care within the first 3 months of enrollment. After implementation of revised guidelines in 2009, decentralization of care and increased access to prevention of mother to child transmission services, we observed an increase in infants (48.9%-68.3%; P < 0.0001) and children (48.9%-68.3%; P < 0.0001) remaining in care for more than 3 months. Children enrolled from 2009 were younger, had lower World Health Organization clinical stage, improved baseline CD4 counts than those who enrolled in 2004-2008. Long-term retention in care also improved with decreasing risk of loss from care at 36 months for infants enrolled from 2009 (aHR: 0.57; 95% confidence interval: 0.34-0.95; P = 0.031). ART eligibility at enrollment was a significant predictor of long-term retention in care, while delayed ART initiation after 5 years of age resulted in failure to fully reconstitute CD4 counts to age-appropriate levels despite prolonged ART.

CONCLUSIONS

Significant improvements have been made in engaging and retaining children in care in public ART programs in Zimbabwe. Guideline and policy changes that increase access and eligibility will likely to continue to support improvement in pediatric HIV outcomes.

Toll-like receptor 9 polymorphism is associated with increased Epstein-Barr virus and Cytomegalovirus acquisition in HIV-exposed infants

: Polymorphisms in the Toll-like receptor 9 1635 locus have been associated with HIV-1 acquisition and progression. Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) acquisition were compared between Kenyan HIV-exposed infants by 1635 genotype. Having one or more copies of the 1635A allele was associated with increased CMV acquisition in HIV-infected infants (42 vs. 11%, P = 0.03) and increased risk of EBV acquisition in HIV-exposed uninfected infants (hazard ratio = 4.2, P = 0.02) compared with 1635GG. In addition, 1635A was associated with 0.4 log10 copies/ml lower median EBV levels in HIV-infected infants (P = 0.03). These data suggest a potentially important role for this locus in primary herpesvirus infection.

HIV-1 at the placenta: immune correlates of protection and infection

PURPOSE OF REVIEW

Mother-to-child transmission (MTCT) of HIV-1 remains a significant global health concern despite implementation of maternal combination antiretroviral therapy for treatment as prevention to offset transmission. The risk of in-utero HIV-1 transmission in the absence of interventions is ∼7%. This low rate of transmission points to innate and adaptive mechanisms to restrict lentiviral infection within the placenta.

RECENT FINDINGS

Placental macrophages (Hofbauer cells) are key mediators in in-utero transmission of HIV-1. Hofbauer cells constitutively express elevated concentrations of regulatory cytokines, which inhibit HIV-1 replication in vitro, and possess intrinsic antiviral properties. Hofbauer cells sequester HIV-1 in intracellular compartments that can be accessed by HIV-1-specific antibodies and may occur in vivo to offset MTCT. Intriguingly, studies have reported strong associations between maternal human cytomegalovirus (HCMV) viremia and MTCT of HIV-1. HCMV infection at the placenta promotes inflammation, chronic villitis, and trophoblast damage, providing potential HIV-1 access into CD4CCR5 target cells. The placenta exhibits a variety of mechanisms to limit HIV-1 replication, yet viral-induced activation with maternal HCMV may override this protection to facilitate in-utero transmission of HIV-1.

SUMMARY

Understanding immune correlates of protection or transmission at the placenta during on-going HIV-1 exposure may contribute to understanding HIV pathogenesis and the development of effective immunotherapies.

High CMV IgG antibody levels are associated to a lower CD4+ RESPONSE to antiretroviral therapy in HIV-infected women

BACKGROUND

Virtually all HIV-infected women in sub-Saharan Africa have evidence of Cytomegalovirus (CMV) infection and levels of specific anti-CMV IgG have been suggested to represent more intense reactivation of subclinical infection. Studies have also shown direct influence of CMV on lymphocytes.

OBJECTIVE

The aim of this study was to determine if levels of anti-CMV specific antibodies could impact on the immunological response to antiretroviral treatment (ART) in HIV-infected pregnant women.

STUDY DESIGN

CMV-specific IgG were measured in HIV-infected pregnant women at 26 weeks of gestation (before ART initiation). Women received ART until 6 months postpartum or indefinitely according to local guidelines at the time of the study. Immunological and virological responses were assessed 6 months and 24 months after delivery.

RESULTS

A total of 81 women were studied. At baseline high levels (above the median) of specific IgG were associated to a low CD4+ cell count (P<0.001), a high viral load (P=0.003), and to an older age (P=0.051). In a multivariate model adjusting for baseline CD4+ count, baseline viral load and age, the presence of low levels of CMV IgG was the only independent predictor of a a CD4+ count above 500/mm³ 24 months after delivery among women on continuous therapy.

CONCLUSIONS

In this cohort, levels of CVM IgG had a significant influence on the immunological response to ART, adding information to the known impact of CMV infection in the HIV-positive population, and underlining the need of new strategies to contain the infection.

Cytomegalovirus viraemia is associated with poor growth and T-cell activation with an increased burden in HIV-exposed uninfected infants

Objective:

Factors associated with poor health in HIV-exposed-uninfected (HEU) infants are poorly defined. We describe the prevalence and correlates of cytomegalovirus (CMV) viraemia in HEU and HIV-unexposed-uninfected (HUU) infants, and quantify associations with anthropometric, haematological, and immunological outcomes.

Design:

Cross-sectional, including HEU and HUU infants from rural coastal Kenya.

Methods:

Infants aged 2–8 months were studied. The primary outcome was CMV viraemia and viral load, determined by quantitative PCR. Correlates were tested by logistic and linear regression; coefficients were used to describe associations between CMV viraemia and clinical/immunological parameters.

Results:

In total, 42 of 65 (64.6%) infants had CMV viraemia [median viral load, 3.0 (interquartile ranges: 2.7–3.5) log₁₀ IU/ml]. Compared to community controls, HEU infants had six-fold increased odds of being viraemic (adjusted odds ratio 5.95 [95% confidence interval: 1.82–19.36], P = 0.003). Age, but not HEU/HUU status, was a strong correlate of CMV viral load (coefficient = −0.15, P = 0.009). CMV viral load associated negatively with weight-for-age (WAZ) Z-score (coefficient =  −1.06, P = 0.008) and head circumference-for-age Z-score (coefficient =  −1.47, P = 0.012) and positively with CD8⁺ T-cell coexpression of CD38/human leucocyte antigen DR (coefficient = 15.05, P = 0.003).

Conclusion:

The odds of having CMV viraemia was six-fold greater in HEU than HUU infants when adjusted for age. CMV viral load was associated with adverse growth and heightened CD8⁺ T-cell immune activation. Longitudinal assessments of the clinical effects of primary CMV infection and associated immunomodulation in early life in HEU and HUU populations are warranted.

Maternal Highly Active Antiretroviral Therapy Reduces Vertical Cytomegalovirus Transmission But Does Not Reduce Breast Milk Cytomegalovirus Levels

To evaluate the impact of highly active antiretroviral therapy (HAART) on CMV transmission and breast milk level in the context of maternal HIV. Specimens from a randomized trial conducted in Nairobi, Kenya between 2003-2005 were used to compare CMV transmission and breast milk levels between mother-infant pairs randomized to HAART versus short-course antenatal zidovudine plus single-dose nevirapine (ZDV/sdNVP) for prevention of mother-to-child HIV transmission (PMTCT). Fifty-one antiretroviral-naïve women ≤32 weeks gestation, and CD4 between 200-500 cells/mm³ were randomized at 34 weeks to begin either antenatal ZDV/sdNVP, or HAART through 6 months postpartum. Mean breast milk CMV levels and transmission were compared between arms. Age, sociodemographics, CD4%, and HIV plasma RNA viral load were similar between arms at baseline. CMV viral loads were measured from 243 infant plasma and 185 breast milk specimens during the first year postpartum. The probability of infant CMV infection at 12 months was 19% lower in the HAART arm compared to ZDV/sdNVP (75% vs. 94%, p = .04). All women had CMV detected in breast milk, with 72%, 98%, and 97% testing positive during the first, second, and third weeks postpartum, respectively. There was a trend for early higher mean breast milk CMV level in the HAART arm at 1 week (p = .08), and there was significantly slower decline in breast milk CMV levels (area under the curve, p = .01). HAART started during the third trimester may decrease infant CMV infections, by mechanisms independent of breast milk CMV levels.

CLINICAL TRIALS REGISTRATION

NCT00167674.

Cytomegalovirus infection in HIV-infected versus non-infected infants and HIV disease progression in Cytomegalovirus infected versus non infected infants early treated with cART in the ANRS 12140-Pediacam study in Cameroon

Background

The outcome of CMV/HIV co-infection in infants treated early with combined antiretroviral therapy (cART) in resource-limited settings has not been described.

We aimed to estimate the prevalence and identify factors associated with early CMV infection in HIV-infected and non-infected infants included in a study in Cameroon, and to compare HIV disease progression and survival after 1 year of early cART, following infants’ CMV status.

Methods

HIV-infected infants followed from birth or from HIV diagnosis before 7 months old and HIV-uninfected infants born to HIV-infected or uninfected mothers were tested for CMV at a median age of 4.0 months [Interquartile range (IQR): 3.4–4.9]. Multivariable logistic regression was performed to identify factors associated with CMV infection. Early cART was offered to HIV-infected infants: mortality, immunological and virological outcomes were assessed.

Results

Three hundred and sixty-nine infants were tested. The proportion of infants infected with CMV at baseline was significantly higher in HIV-infected than in HIV-uninfected groups (58.9% (86/146) vs 30.0% (67/223), p < 0.001). At baseline, median CMV viral load was higher in HIV-infected (3.7 log copies/ml [IQR; 3.1–4.3]) than in HIV-uninfected infants (2.8 log copies [IQR; 2.1–3.4], p < 0.001). cART was initiated in 90% of HIV-infected infants (132/146) at a median age of 4.0 months (IQR; 3.2–5.9); in this sub-group CMV infection was independently associated with being followed from the time of HIV diagnosis rather than from birth (aOR = 3.1, 95%CI [1.2–8.0]), born to a non-single mother (aOR = 3.4[1.4–8.1]), and breastfeeding (aOR = 7.3 [2.7–19.4]). HIV-infected infants were retested after a median of 7.1 months [4.8–9.5]: CMV was undetectable in 37 of the 61 (60.7%) initially CMV-infected cases and became detectable in 8 of the 38 (21.1%) initially CMV-negative cases. After 1 year of cART, the probability of death (0.185 vs 0.203; p = 0.75), the proportion of cases with HIV RNA viral load <400 copies/ml (75.5% vs 61.5%; p = 0.17) and the mean CD4 percentage increase (10.97% vs 6.88%; p = 0.15) did not differ between CMV+ and CMV- infants.

Conclusions

We observed a high prevalence of CMV infection among HIV-infected infants. Early initiation of cART may have limited the negative impact of CMV even in the absence of specific anti-CMV treatment.

Cytomegalovirus in pregnancy and the neonate

Congenital cytomegalovirus (CMV) remains a leading cause of disability in children. Understanding the pathogenesis of infection from the mother via the placenta to the neonate is crucial if we are to produce new interventions and provide supportive mechanisms to improve the outcome of congenitally infected children. In recent years, some major goals have been achieved, including the diagnosis of primary maternal CMV infection in pregnant women by using the anti-CMV IgG avidity test and the diagnosis and prognosis of foetal CMV infection by using polymerase chain reaction real-time tests to detect and quantify the virus in amniotic fluid. This review summarises recent advances in our understanding and highlights where challenges remain, especially in vaccine development and anti-viral therapy of the pregnant woman and the neonate. Currently, no therapeutic options during pregnancy are available except those undergoing clinical trials, whereas valganciclovir treatment is recommended for congenitally infected neonates with moderately to severely symptomatic disease.

Ontogeny of CD4+ T Lymphocytes With Phenotypic Susceptibility to HIV-1 During Exclusive and Nonexclusive Breastfeeding in HIV-1-Exposed Ugandan Infants

Background

Among infants exposed to human immunodeficiency virus (HIV) type 1, mixed breastfeeding is associated with higher postnatal HIV-1 transmission than exclusive breastfeeding, but the mechanisms of this differential risk are uncertain.

Methods

HIV-1-exposed Ugandan infants were prospectively assessed during the first year of life for feeding practices and T-cell maturation, intestinal homing (β7hi), activation, and HIV-1 coreceptor (CCR5) expression in peripheral blood. Infants receiving only breast milk and those with introduction of other foods before 6 months were categorized as exclusive and nonexclusive, respectively.

Results

Among CD4+ and CD8+ T cells, the expression of memory, activation, and CCR5 markers increased rapidly from birth to week 2, peaking at week 6, whereas cells expressing the intestinal homing marker increased steadily in the central memory (CM) and effector memory T cells over 48 weeks. At 24 weeks, when feeding practices had diverged, nonexclusively breastfed infants showed increased frequencies and absolute counts of β7hi CM CD4+ and CD8+ T cells, including the HIV-1-targeted cells with CD4+β7hi/CCR5+ coexpression, as well as increased activation.

Conclusions

The T-cell phenotype associated with susceptibility to HIV-1 infection (CCR5+, gut-homing, CM CD4+ T cells) was preferentially expressed in nonexclusively breastfed infants, a group of infants at increased risk for HIV-1 acquisition.

Clinical utility of bronchoalveolar lavage cytomegalovirus viral loads in the diagnosis of cytomegalovirus pneumonitis in infants

Cytomegalovirus (CMV) pneumonitis is a significant cause of morbidity and mortality of children in Africa. The current practice for diagnosing CMV pneumonitis in this setting is based on interpretation of clinical, laboratory, and radiological findings. There is a need for a sensitive and specific laboratory test to objectively distinguish between patients with CMV pneumonitis and those with CMV infection, and non‐CMV pneumonia. In this study, we compared plasma and non‐bronchoscopic bronchoalveolar lavage (NBBAL) CMV viral loads in patients with CMV pneumonitis and those with CMV infection and non‐CMV pneumonia. Receiver operator characteristic curve analysis was used to establish a threshold and assess utility of viral loads in the diagnosis of CMV pneumonitis. We assessed the urea dilution method, and expression of viral loads relative to the total amount of extracted nucleic acids in correcting for NBBAL dilution. CMV quantification in NBBAL specimens was more predictive of CMV pneumonitis than blood CMV quantification. The threshold of 4.03 log IU/ml in NBBAL specimens has good predictive value and can be used to guide management of infants with suspected CMV pneumonitis. Adjusting for dilution of NBBAL specimens by using the urea dilution method or by expressing the viral load relative to the total nucleic acids extracted did not provide additional analytical benefits. J. Med. Virol. 89:1080–1087, 2017. © 2016 Wiley Periodicals, Inc.

Risk Factors for Presumed Bacterial Pneumonia Among HIV-uninfected Children Hospitalized in Soweto, South Africa

BACKGROUND

Pneumonia is a leading cause of child morbidity and death. Data on risk factors can guide prevention efforts. Within a study on pneumococcal conjugate vaccine effectiveness, we investigated risk factors for presumed bacterial pneumonia (PBP).

METHODS

PBP cases were human immunodeficiency virus (HIV) uninfected children with lower respiratory tract infection and consolidation on chest radiograph or nonconsolidated infiltrate with C-reactive protein ≥40 mg/L hospitalized at Chris Hani Baragwanath Academic Hospital (CHBAH) in Soweto. Age-matched community controls were identified using CHBAH birth records ±1 week of case birth date. Data were analyzed using conditional logistic regression.

RESULTS

A total of 889 PBP cases (median age 9 months) were matched to 2628 controls. Crowding was a significant risk factor among well-nourished children (adjusted odds ratio [aOR]: 2.29, 95% confidence interval [CI]: 1.89-2.78), but not in those with low weight-for-age. Malnutrition was associated with PBP; strength of association was highest in the absence of crowding (aOR: 6.68, 95% CI: 4.74-9.42). Exclusive breastfeeding was protective only among HIV-unexposed children (aOR: 0.65, 95% CI: 0.54-0.78). Self-reported maternal HIV infection was a risk factor among children exclusively breastfeed up to 4 months (aOR: 2.33, 95% CI: 1.53-3.55). Having indoor tap water was protective (aOR: 0.65, 95% CI: 0.54-0.78), whereas a primary care giver who smoked was a risk factor (aOR: 5.15, 95% CI: 2.94-9.03).

CONCLUSIONS

Our findings confirm several known pneumonia risk factors and highlight complex interactions between factors, including HIV exposure, breastfeeding, malnutrition and crowding. Improved housing, reduced secondhand smoke exposure and HIV prevention among women of reproductive age could lessen the child pneumonia burden.

Review of cytomegalovirus coinfection in HIV-infected individuals in Africa

BACKGROUND

Cytomegalovirus (CMV) infection among HIV-infected individuals may cause end-organ disease, which is an AIDS-defining condition. Evidence from high-income countries suggests that CMV may alter the outcome of HIV infection, other than causing end-organ diseases. We reviewed literature on HIV and CMV coinfection in Africa.

METHODS

Systematic review of published studies on HIV and CMV coinfection in Africa using the PubMed database.

RESULTS

High CMV seroprevalence was found throughout Africa, exceeding 90% in most populations. Retinitis, pneumonia, and colitis were the most commonly reported CMV manifestations in HIV-infected individuals. Among patients with pulmonary symptoms, the prevalence of CMV pneumonitis varied from 20% to over 60%, whereas CMV was found in 0% to 14% of patients with gastrointestinal manifestations. Cytomegalovirus retinitis was found in 0% to 2.6% of examined HIV-infected individuals. The diagnostics of CMV end-organ diseases were found complex and difficult to interpret in African settings. Cytomegalovirus viremia was correlated with significantly lower CD4 cell count and increase in activated and apoptosis vulnerable T-lymphocytes. Also, CMV coinfection was found to be associated with increased transmission and progression of HIV infection. Moreover, detectable CMV DNA was an independent predictor of HIV transmission and mortality among HIV-infected individuals.

CONCLUSIONS

Cytomegalovirus is highly prevalent in Africa and a common cause of disease manifestations in HIV-infected individuals among all age groups. Cytomegalovirus coinfection in HIV-infected individuals in Africa is associated with increased transmission and mortality of HIV, but it is a neglected area of research.

Cytomegalovirus and paediatric HIV infection

Cytomegalovirus (CMV) was among the most common AIDS-defining illnesses prior to the advent of combination antiretroviral therapy (ART). In the ART era, CMV disease remains a significant public health threat among HIV-infected adults and children with delayed HIV diagnosis. CMV co-infection may additionally contribute to accelerated HIV progression, development of inflammation-related comorbidities, immune senescence and developmental deficits. Elimination of CMV would have tremendous public health significance and is an important priority; however, current vaccine strategies are not targeted at HIV-infected individuals. Antivirals active against CMV may be a novel strategy to prevent acquisition and improve outcomes, but haematological side effects are common and necessitate cautious use in pregnant women and infants. Studies in HIV-infected children on ART lag behind adults, and the clinical significance of CMV in this population is not well understood. Furthermore, the effects of CMV in HIV-exposed uninfected (HEU) children need to be clarified to understand whether CMV interventions should also be a priority for this growing population. This review discusses our current understanding of CMV transmission and pathogenesis in HIV-exposed children and highlights unanswered questions for future research.

CMV infection in a cohort of HIV-exposed infants born to mothers receiving antiretroviral therapy during pregnancy and breastfeeding

Antiretroviral therapy has been shown to reduce rates of congenital CMV infection. Little information is available on the possible impact of antiretroviral therapy on postnatal breastfeeding-associated CMV infection acquisition. A cohort of 89 HIV-infected mothers and their children was studied. Women received antiretroviral therapy from week 25 of gestation until 6 months postpartum or indefinitely if meeting the criteria for treatment. All women were evaluated for CMV IgG presence and CMV DNA in breast milk. Children were tested for CMV infection by either the presence of IgM or the presence of CMV DNA in plasma at 1, 6 and 12 months and by the presence of IgG at 24 months. All mothers had high titers of CMV DNA in breast milk (5.7 log at Month 1 and 5.1 log at Month 6). Cumulative CMV infection rates were 60.3 % at Month 6, 69 % at Month 12 and 96.4 % at Month 24. There was a significant negative correlation between the duration of antiretroviral treatment during pregnancy and levels of CMV DNA in breast milk at Month 1 (P = 0.033). There was a trend for a correlation between high titers of CMV DNA in breast milk at 6 months and CMV infection at 6 months (P = 0.069). In this cohort, more than 95 % of the children had acquired CMV infection by 2 years of age. Besides breastfeeding, which played a major role, also horizontal transmission between 1 and 2 years was certainly relevant in determining CMV infection acquisition.

Human cytomegalovirus (CMV) in Africa: a neglected but important pathogen

In Africa, human cytomegalovirus (CMV) is an important pathogen in a diverse range of patient groups. Congenital CMV infection is common, and most children undergo primary infection during the first year of life. Preliminary studies suggest that these early primary CMV infections could have population-wide effects on growth and development. In most studies of adults, CMV seroprevalence is close to 100%, but some studies have found that significant minorities of adults are seronegative. CMV is a common cause of pneumonia and meningitis in hospitalised immunosuppressed patient groups, and CMV DNAemia may be an important marker of rapid progression and poor outcomes of HIV infection, despite roll-out of antiretroviral therapy (ART). Diagnosis and treatment of CMV-related disease is broadly neglected in Africa, and no randomised clinical trials of anti-CMV drugs have been conducted to date. Autopsy is rarely performed in Africa, but identifies CMV as a frequent pathogen when it is carried out. Here we review the available literature on CMV in Africa, primarily in adult patients, and discuss this in the context of contemporary understanding of CMV as a human pathogen.

Cytomegalovirus Infection May Contribute to the Reduced Immune Function, Growth, Development, and Health of HIV-Exposed, Uninfected African Children

With increasing access to antiretroviral therapy (ART) in Africa, most children born to HIV-infected mothers are not themselves HIV-infected. These HIV-exposed, uninfected (HEU) children are at increased risk of mortality and have immune, growth, development, and health deficits compared to HIV-unexposed children. HEU children are known to be at higher risk than HIV-unexposed children of acquiring cytomegalovirus (CMV) infection in early life. This risk is largely unaffected by ART and is increased by breastfeeding, which itself is critically important for child health and survival. Early CMV infection, namely in utero or during early infancy, may contribute to reduced growth, altered or impaired immune functions, and sensory and cognitive deficits. We review the evidence that CMV may be responsible for the health impairments of HEU children. There are currently no ideal safe and effective interventions to reduce postnatal CMV infection. If a clinical trial showed proof of the principle that decreasing early CMV infection improved health and development of HEU children, this could provide the impetus needed for the development of better interventions to improve the health of this vulnerable population.

HIV-Exposed Uninfected Infants in Zimbabwe: Insights into Health Outcomes in the Pre-Antiretroviral Therapy Era

The ZVITAMBO trial recruited 14,110 mother-infant pairs to a randomized controlled trial of vitamin A between 1997 and 2000, before the availability of antiretroviral therapy for HIV prophylaxis or treatment in Zimbabwe. The HIV status of mothers and infants was well characterized through 1-2 years of follow-up, leading to the largest cohort to date of HIV-exposed uninfected (HEU) infants (n = 3135), with a suitable comparison group of HIV-unexposed infants (n = 9510). Here, we draw on 10 years of published findings from the ZVITAMBO trial. HEU infants had increased morbidity compared to HIV-unexposed infants, with 50% more hospitalizations in the neonatal period and 30% more sick clinic visits during infancy, particularly for skin infections, lower respiratory tract infections, and oral thrush. HEU children had 3.9-fold and 2.0-fold higher mortality than HIV-unexposed children during the first and second years of life, respectively, most commonly due to acute respiratory infections, diarrhea/dysentery, malnutrition, sepsis, and meningitis. Infant morbidity and mortality were strongly related to maternal HIV disease severity, and increased morbidity remained until maternal CD4 counts were >800 cells/μL. HEU infants were more likely to be premature and small-for-gestational age than HIV-unexposed infants, and had more postnatal growth failure. Here, we propose a conceptual framework to explain the increased risk of infectious morbidity, mortality, and growth failure among HEU infants, hypothesizing that immune activation and inflammation are key drivers of both infection susceptibility and growth failure. Future studies should further dissect the causes of infection susceptibility and growth failure and determine the impact of ART and cotrimoxazole on outcomes of this vulnerable group of infants in the current era.

Seroprevalence of CMV, HSV-2 and HBV among HIV-Infected Malawian Children: A Cross-sectional Survey

BACKGROUND

Little is known about viral co-infections in African human immunodeficiency virus (HIV)-infected children. We examined the prevalence of seromarkers for cytomegalovirus (CMV), herpes simplex virus type 2 (HSV-2) and hepatitis B virus (HBV) infections among HIV-infected, antiretroviral treatment (ART)-naïve children in Lilongwe, Malawi.

METHODS

Ninety-one serum samples were tested for IgG and IgM antibodies to CMV, and IgG antibodies to HSV-2 and hepatitis B surface antigen (HBsAg). Baseline demographic, clinical and laboratory data were abstracted from electronic records.

RESULTS

CMV IgG was the most common positive result in all age groups (in 73% of children <1 year, and 100% in all other groups). Three patients were CMV IgM positive (3.3%), suggesting acute infection. HSV-2 IgG was positive in four patients (4.4%), and HBsAg in two (2.2%).

CONCLUSIONS

CMV infection occurred early in life, and few children had specific signs of CMV infection at the time of ART initiation. Unrecognized HBV infection represents opportunities for testing and treatment of HIV/HBV co-infected children.

Risk of congenital cytomegalovirus infection among HIV-exposed uninfected infants is not decreased by maternal nelfinavir use during pregnancy

BACKGROUND

Congenital cytomegalovirus (cCMV) infection is common among infants born to HIV-infected women. Nelfinavir (NFV), an antiretroviral drug that is safe during pregnancy, inhibits CMV replication in vitro at concentrations that standard doses achieve in plasma. We hypothesized that infants born to women receiving NFV for prevention of mother-to-child transmission of HIV (PMTCT) would have a reduced prevalence of cCMV infection.

METHODS

The prevalence of cCMV infection was compared among HIV-uninfected infants whose HIV-infected mothers either received NFV for >4 weeks during pregnancy (NFV-exposed) or did not receive any NFV in pregnancy (NFV-unexposed). CMV PCR was performed on infant blood samples collected at <3 weeks from birth.

RESULTS

Of the 1,255 women included, 314 received NFV for >4 weeks during pregnancy and 941 did not receive any NFV during pregnancy. The overall prevalence of cCMV infection in the infants was 2.2%, which did not differ by maternal NFV use. Maternal CD4 T cell counts were inversely correlated with risk of cCMV infection, independent of the time NFV was initiated during gestation. Infants with cCMV infection were born 0.7 weeks earlier (P = 0.010) and weighed 170 g less (P = 0.009) than uninfected infants.

CONCLUSION

Among HIV-exposed uninfected infants, cCMV infection was associated with adverse perinatal outcomes. NFV use in pregnancy was not associated with protection against cCMV. Safe and effective strategies to prevent cCMV infection are needed.

Single Chain Antibodies Against gp55 of Human Cytomegalovirus (HCMV) for Prophylaxis and Treatment of HCMV Infections

Background:

Immunotherapy is a promising prospective new treatment for cytomegalovirus (CMV) infections. Neutralizing effects have been reported using monoclonal antibodies. Recombinant single chain antibodies (scFvs) due to their advantages over monoclonal antibodies are potential alternatives and provide valuable clinical agents.

Objectives:

The aim of this study was to select specific single chain antibodies against gp55 of CMV and to evaluate their neutralizing effects. In the present study, we selected specific single chain antibodies against glycoprotein 55 (gp55) of CMV for their use in treatment and diagnosis.

Materials and Methods:

Single chain antibodies specific against an epitope located in the C-terminal part of gp55 were selected from a phage antibody display library. After four rounds of panning, twenty clones were amplified by the polymerase chain reaction (PCR) and fingerprinted by MvaI restriction enzyme. The reactivities of the specific clones were tested by the enzyme-linked immunosorbent assay (ELISA) and the neutralizing effects were evaluated by the plaque reduction assay.

Results:

Fingerprinting of selected clones revealed three specific single chain antibodies (scFv1, scFv2 and scFv3) with frequencies 25%, 20 and 20%. The clones produced positive ELISA with the corresponding peptide. The percentages of plaque reduction for scFv1, scFv2 and scFv3 were 23.7, 68.8 and 11.6, respectively.

Conclusions:

Gp55 of human CMV is considered as an important candidate for immunotherapy. In this study, we selected three specific clones against gp55. The scFvs reacted only with the corresponding peptide in a positive ELISA. The scFv2 with 68.8% neutralizing effect showed the potential to be considered for prophylaxis and treatment of CMV infections, especially in solid organ transplant recipients, for whom treatment of CMV is urgently needed. The scFv2 with neutralizing effect of 68.8%, has the potential to be considered for treatment of these patients. The specific scFv1 and scFv3 with lower neutralizing effects can be used for diagnostic purposes.

Cytomegalovirus IgG Level and Avidity in Breastfeeding Infants of HIV-Infected Mothers in Malawi

Cytomegalovirus (CMV) infection is common among infants of HIV-infected mothers in resource-limited settings. We examined the prevalence and timing of infant CMV infection during the first year of life using IgG antibody and avidity among HIV-exposed infants in Malawi and correlated the results with the presence of detectable CMV DNA in the blood. The Breastfeeding, Antiretrovirals and Nutrition (BAN) study randomized 2,369 mothers and their infants to maternal antiretrovirals, infant nevirapine, or neither for 28 weeks of breastfeeding, followed by weaning. Stored plasma specimens were tested for CMV IgG and antibody avidity from a random subset of infants who had been previously tested with blood CMV PCR and had available specimens at birth and at 24 and 48 weeks of age. Ninety-four of 127 infants (74.0%) tested at 24 weeks of age had CMV IgG of low or intermediate avidity, signifying primary CMV infections. An additional 22 infants (17.3%) had IgG of high avidity; 19 of them had CMV DNA detected in their blood, indicating infant infections. Taken together, these results show that the estimated prevalence of CMV infection at 24 weeks was 88.9%. By 48 weeks of age, 81.3% of infants had anti-CMV IgG; most of them (70.9%) had IgG of high avidity. The CMV serology and avidity testing, combined with the PCR results, confirmed a high rate of primary CMV infection by 6 months of life among breastfeeding infants of HIV-infected mothers. The CMV PCR in blood detected most, but not all, infant CMV infections.

Cytomegalovirus Infection in Human Immunodeficiency Virus (HIV)-Exposed and HIV-Infected Infants: A Systematic Review

Cytomegalovirus is highly prevalent worldwide and an important opportunistic pathogen in human immunodeficiency virus (HIV)-infected individuals. The effects of cytomegalovirus infection on HIV-exposed infants are poorly understood. We conducted a systematic review to assess the relationship between cytomegalovirus and HIV infections among HIV-exposed infants. Limited evidence suggests that HIV-induced immunosuppression in the mother increases the rate of congenital cytomegalovirus infection, while maternal antiretroviral therapy may reduce it. Limited information exists on the direction of the relationship between cytomegalovirus and HIV transmission among HIV-exposed infants. Only 2 studies have addressed this temporal sequence of events, and they suggest that cytomegalovirus can lead to subsequent HIV infection in HIV-exposed infants. Most evidence suggests that early cytomegalovirus infection accelerates HIV disease progression in infants. Gaps remain in understanding the role that cytomegalovirus infection plays in HIV-exposed infants. Decreasing cytomegalovirus transmission prenatally and in infancy might further decrease HIV transmission and lead to better health among HIV-exposed infants.

Vertical Cytomegalovirus Transmission From HIV-Infected Women Randomized to Formula-Feed or Breastfeed Their Infants

BACKGROUND

Cytomegalovirus (CMV) is associated with morbidity and mortality in human immunodeficiency virus (HIV)-exposed infants. We assessed the effect of and relative contribution of breastfeeding to CMV acquisition among infants delivered by HIV-infected mothers.

METHODS

Between 1993 and 1998 pregnant, HIV-infected women in Nairobi, Kenya, were randomly assigned to breastfeed or formula-feed their infants in an HIV transmission study. Women were allocated equally between treatment arms, and the study was not blinded. The primary endpoint of this nested study was time to infant CMV infection.

RESULTS

CMV infection was assessed in 138 breastfed and 134 formula-fed infants. Baseline characteristics were similar between arms. Breastfed infants acquired CMV earlier than formula-fed infants (median age of acquisition, 4.26 vs 9.87 months; P < .001) and had a higher 1-year probability of CMV infection (0.89 vs 0.69; P < .001). Breastfeeding was associated with a 1.6-fold increased risk of infant CMV acquisition independent of infant HIV status (multivariable hazard ratio, 1.61; 95% confidence interval, 1.20-2.16; P = .002). Approximately one third of CMV infections occurred during the peripartum period, with 40% acquired through breastfeeding and the remainder acquired through modes other than breast milk.

CONCLUSIONS

Preventing CMV acquisition may be a priority for HIV-exposed infants, but there is a narrow window of opportunity for intervention. Approaches that reduce maternal cervical and breast milk CMV reactivation may help delay infant infection.

Effect of cytomegalovirus infection on breastfeeding transmission of HIV and on the health of infants born to HIV-infected mothers

BACKGROUND

Cytomegalovirus (CMV) infection can be acquired in utero or postnatally through horizontal transmission and breastfeeding. The effect of postnatal CMV infection on postnatal HIV transmission is unknown.

METHODS

The Breastfeeding, Antiretrovirals and Nutrition study, conducted in Malawi, randomized 2369 mothers and their infants to three antiretroviral prophylaxis arms - mother (triple regimen), infant (nevirapine), or neither - for 28 weeks of breastfeeding, followed by weaning. Stored plasma and peripheral blood mononuclear cell specimens were available for 492 infants at 24 weeks and were tested with CMV PCR. Available samples from infants who were CMV PCR-positive at 24 weeks were also tested at birth (N = 242), and from infants PCR-negative at 24 weeks were tested at 48 weeks (N = 96). Cox proportional-hazards models were used to determine if CMV infection was associated with infant morbidity, mortality, or postnatal HIV acquisition.

RESULTS

At 24 weeks of age, CMV DNA was detected in 345/492 infants (70.1%); the estimated congenital CMV infection rate was 2.3%, and the estimated rate of CMV infection at 48 weeks was 78.5%. CMV infection at 24 weeks was associated with subsequent HIV acquisition through breastfeeding or infant death between 24 and 48 weeks of age (hazard ratio 4.27, P = 0.05).

CONCLUSION

Most breastfed infants of HIV-infected mothers in this resource-limited setting are infected with CMV by 24 weeks of age. Early CMV infection may be a risk factor for subsequent infant HIV infection through breastfeeding, pointing to the need for comprehensive approaches in order to achieve elimination of breastfeeding transmission of HIV.

Congenital and postnatal CMV and EBV acquisition in HIV-infected Zimbabwean infants

Background

HIV-infected infants in sub-Saharan Africa have rapid disease progression. We hypothesized that co-infection with cytomegalovirus (CMV) or Epstein Barr virus (EBV) increases mortality in HIV-infected infants.

Methods

257 antiretroviral therapy-naïve HIV-infected Zimbabwean infants were tested for CMV and EBV at 6 weeks of age by real-time PCR; if positive, birth samples were retrieved where available to distinguish congenital and postnatal infection. The impact of co-infection on mortality through 6 months was estimated using Kaplan-Meier and Cox proportional hazards methods.

Results

At 6 weeks, 203/257 (79%) HIV-infected infants were CMV-positive; 27 (11%) had congenital CMV, 108 (42%) postnatal CMV and 68 (26%) indeterminate timing of infection. By 6 months, 37/108 (34%) infants with postnatal CMV versus 16/54 (30%) CMV-negative infants died (adjusted hazard ratio (aHR) 1.1 [95%CI 0.6, 2.2]). At 6 weeks, 33/257 (13%) HIV-infected infants had EBV co-infection; 6 (2%) had congenital EBV, 18 (7%) postnatal EBV and 9 (4%) indeterminate timing of infection. By 6 months, 5/18 (28%) infants with postnatal EBV versus 72/224 (32%) EBV-negative infants died (aHR 0.8 [95%CI 0.3, 2.3]).

Conclusions

The vast majority of HIV-infants had acquired CMV by 6 weeks, and EBV co-infection occurred earlier than expected, with one in eight HIV-infected infants positive for EBV by 6 weeks. There was a high prevalence of congenital CMV infection and we identified 6 infants with congenital EBV infection, which has not previously been reported in Africa or in the context of HIV infection. Neither CMV nor EBV co-infection was associated with increased mortality.

In-utero infection with HIV-1 associated with suppressed lymphoproliferative responses at birth

In-utero exposure to HIV-1 may affect the immune system of the developing child and may induce HIV-1-specific immune responses, even in the absence of HIV-1 infection. We evaluated lymphoproliferative capacity at birth among 40 HIV-1-uninfected infants born to HIV-1-infected mothers and 10 infants who had acquired HIV-1 in utero. Cord blood mononuclear cells were assayed using [(3) H]-thymidine incorporation for proliferation in response to HIV-1 p55-gag and the control stimuli phytohaemagglutinin (PHA), Staphylococcus enterotoxin B (SEB) and allogeneic cells. In response to HIV-1 p55-gag, eight (20%) HIV-1-exposed, uninfected (EU) infants had a stimulation index (SI) ≥ 2 and three (30%) in-utero HIV-1 infected infants had SI ≥2. The frequency and magnitude of responses to HIV-1 p55-gag were low overall, and did not differ statistically between groups. However, proliferative responses to control stimuli were significantly higher in EU infants than in infants infected in utero, with a median SI in response to PHA of 123 [interquartile range (IQR) 77-231] versus 18 (IQR 4-86) between EU and infected infants, respectively (P < 0·001). Among infected infants, gestational maturity was associated with the strength of HIV-1 p55-gag response (P < 0·001); neither maternal nor infant HIV-1 viral load was associated. In summary, EU and HIV-1-infected infants mounted HIV-1-specific lymphoproliferative responses at similar rates (20-30%), and although global immune function was preserved among EU infants, neonatal immune responses were significantly compromised by HIV-1 infection. Such early lymphoproliferative compromise may, in part, explain rapid progression to AIDS and death among HIV-1-infected infants.

Cytomegalovirus upregulates expression of CCR5 in central memory cord blood mononuclear cells, which may facilitate in utero HIV type 1 transmission

Administration of combination antiretroviral therapy to human immunodeficiency virus type 1 (HIV-1)-infected pregnant women significantly reduces vertical transmission. In contrast, maternal co-opportunistic infection with primary or reactivated cytomegalovirus (CMV) or other pathogens may facilitate in utero transmission of HIV-1 by activation of cord blood mononuclear cells (CBMCs). Here we examine the targets and mechanisms that affect fetal susceptibility to HIV-1 in utero. Using flow cytometry, we demonstrate that the fraction of CD4(+)CD45RO(+) and CD4(+)CCR5(+) CBMCs is minimal, which may account for the low level of in utero HIV-1 transmission. Unstimulated CD4(+) CBMCs that lack CCR5/CD45RO showed reduced levels of HIV-1 infection. However, upon in vitro stimulation with CMV, CBMCs undergo increased proliferation to upregulate the fraction of T central memory cells and expression of CCR5, which enhances susceptibility to HIV-1 infection in vitro. These data suggest that activation induced by CMV in vivo may alter CCR5 expression in CD4(+) T central memory cells to promote in utero transmission of HIV-1.

Systematic review of the birth prevalence of congenital cytomegalovirus infection in developing countries

BACKGROUND

Congenital cytomegalovirus (CMV) infection is the leading infectious cause of congenital hearing loss and neurodevelopmental disability in developed countries. Information on congenital CMV infection in developing countries appears to be lacking.

METHODS

We conducted a systematic literature review to identify studies from developing countries with population-based samples of at least 300 infants that used laboratory methods established as reliable for the diagnosis of congenital CMV infection.

RESULTS

Most studies were excluded due to biased samples or inadequate diagnostic methods; consequently the search identified just 11 studies that were from Africa, Asia, and Latin America. The number of newborns tested ranged from 317 to 12 195. Maternal CMV seroprevalence ranged from 84% to 100%. CMV birth prevalence varied from 0.6% to 6.1%. CMV-associated impairments were not documented in most studies.

CONCLUSIONS

Birth prevalence ranges were higher than for Europe and North America, as expected based on the higher maternal CMV seroprevalence. With very limited data available on sequelae, the disease burden of congenital CMV in developing countries remains largely unknown at this time.

Postnatal cytomegalovirus exposure in infants of antiretroviral-treated and untreated HIV-infected mothers

HIV-1 and CMV are important pathogens transmitted via breastfeeding. Furthermore, perinatal CMV transmission may impact growth and disease progression in HIV-exposed infants. Although maternal antiretroviral therapy reduces milk HIV-1 RNA load and postnatal transmission, its impact on milk CMV load is unclear. We examined the relationship between milk CMV and HIV-1 load (4-6 weeks postpartum) and the impact of antiretroviral treatment in 69 HIV-infected, lactating Malawian women and assessed the relationship between milk CMV load and postnatal growth in HIV-exposed, breastfed infants through six months of age. Despite an association between milk HIV-1 RNA and CMV DNA load (0.39 log(10) rise CMV load per log(10) rise HIV-1 RNA load, 95% CI 0.13-0.66), milk CMV load was similar in antiretroviral-treated and untreated women. Higher milk CMV load was associated with lower length-for-age (-0.53, 95% CI: -0.96, -0.10) and weight-for-age (-0.40, 95% CI: -0.67, -0.13) Z-score at six months in exposed, uninfected infants. As the impact of maternal antiretroviral therapy on the magnitude of postnatal CMV exposure may be limited, our findings of an inverse relationship between infant growth and milk CMV load highlight the importance of defining the role of perinatal CMV exposure on growth faltering of HIV-exposed infants.