Impact of elevated maternal HIV viral load at delivery on T-cell populations in HIV exposed uninfected infants in Mozambique

Impact of in-utero exposure to HIV and latent TB on infant humoral responses

Introduction

Latent tuberculosis infection (LTBI) is a common coinfection in people living with HIV (PWH). How LTBI and HIV exposure in utero influence the development of infant humoral immunity is not well characterized. To address this question, we assessed the relationship between maternal humoral responses in pregnant women with HIV or with HIV/LTBI on humoral responses in infants to BCG vaccination and TB acquisition.

Methods

Plasma samples were obtained from mother infant pairs during pregnancy (14-34 wks gestation) and in infants at 12 and 44 wks of age from the IMPAACT P1078 clinical trial. LTBI was established by Interferon gamma release assay (IGRA). Progression to active TB (ATB) disease was observed in 5 women at various times after giving birth. All infants were BCG vaccinated at birth and tested for IGRA at 44 weeks. Mtb (PPD, ESAT6/CFP10, Ag85A, LAM), HIV (GP120), and Influenza (HA) specific IgG, IgM, and IgA were measured in plasma samples using a bead based Luminex assay with Flexmap 3D.

Results

In maternal plasma there were no differences in Mtb-specific antibodies or viral antibodies in relation to maternal IGRA status. ATB progressors showed increases in Mtb-specific antibodies at diagnosis compared to study entry. However, when compared to the non-progressors at entry, progressors had higher levels of Ag85A IgG and reduced ESAT6/CFP10 IgG and LAM IgG, IgM, and IgA1. All infants showed a decrease in IgG to viral antigens (HIV GP120 and HA) from 12 to 44 weeks attributed to waning of maternally transferred antibody titers. However, Mtb-specific (PPD, ESAT6/CFP10, Ag85A, and LAM) IgG and IgM increased from 12 to 44 weeks. HIV and HA IgG levels in maternal and 12-week infant plasma were highly correlated, and ESAT6/CFP10 IgG and LAM IgG showed a relationship between maternal and infant Abs. Finally, in the subset of infants that tested IGRA positive at 44 weeks, we observed a trend for lower LAM IgM compared to IGRA- infants at 44 weeks.

Discussion

The results from our study raise the possibility that antibodies to LAM are associated with protection from progression to ATB and support further research into the development of humoral immunity against TB through infection or vaccination.

Immune and Metabolic Alterations in Children with Perinatal HIV Exposure

With the global rollout of mother-to-child prevention programs for women living with HIV, vertical transmission has been all but eliminated in many countries. However, the number of children who are exposed in utero to HIV and antiretroviral therapy (ART) is ever-increasing. These children who are HIV-exposed-but-uninfected (CHEU) are now well recognized as having persistent health disparities compared to children who are HIV-unexposed-and-uninfected (CHUU). Differences reported between these two groups include immune dysfunction and higher levels of inflammation, cognitive and metabolic abnormalities, as well as increased morbidity and mortality in CHEU. The reasons for these disparities remain largely unknown. The present review focuses on a proposed link between immunometabolic aberrations and clinical pathologies observed in the rapidly expanding CHEU population. By drawing attention, firstly, to the significance of the immune and metabolic alterations observed in these children, and secondly, the impact of their healthcare requirements, particularly in low- and middle-income countries, this review aims to sensitize healthcare workers and policymakers about the long-term risks of in utero exposure to HIV and ART.

A comparison of weight gain between HIV exposed uninfected and HIV unexposed uninfected infants who received KMC at Chris Hani Baragwanath Academic Hospital

INTRODUCTION

Kangaroo Mother Care (KMC) has been associated with improved growth in low birthweight infants and reduction in hypothermia, hypoglycaemia, apnoeas, sepsis, hospital stay, and mortality. The growth of HIV-infected children is poorer than those who are HIV-uninfected. There is paucity of data on weight gain in the HIV-exposed uninfected (HEU) infants compared to HIV-unexposed uninfected (HUU) infants receiving KMC.

AIM

This study compared the weight gain of HEU and infants HUU from admission to the KMC ward until 12 months corrected age (CA) follow-up visit.

METHODS

Retrospective record review of the neonates admitted in KMC at Chris Hani Baragwanath Hospital over a 2-year period (2012-2013). The weight gain was assessed via weight velocity using the formula; weight/kg/day from admission to KMC to discharge, and g/ week at term, 3, 6 and 9- and 12-months (CA). The demographics were collected and analyzed using Statistica.

RESULTS

Seventy-seven (129/166) percent of the mothers were HIV negative. HIV negative mothers were younger (25.9 vs. 31.6 years; p = 0.000) and had fewer pregnancies (p = 0.02). There was no difference between the gestational age (30.3 ± 2.53 vs. 30.8 ± 2.88 weeks; p = 0.35) and birthweight (1,345 g ± 234 vs. 1,314 g ± 209; p = 0.47) between HEU and HUU. There were no differences in the weight gain (23.83 g ± 12.2 vs. 23.22 g ± 15.2; p = 0.83) in KMC. There was no differences in weight gain at the different follow-up time points between the two groups.

CONCLUSION

Both HEU and HUU groups of infants showed reasonable weight gain despite maternal HIV status.

Maternal Diarrhea and Antibiotic Use are Associated with Increased Risk of Diarrhea among HIV-Exposed, Uninfected Infants in Kenya

HIV-exposed, uninfected (HEU) children are a growing population at particularly high risk of infection-related death in whom preventing diarrhea may significantly reduce under-5 morbidity and mortality in sub-Saharan Africa. A historic cohort (1999-2002) of Kenyan HEU infants followed from birth to 12 months was used. Maternal and infant morbidity were ascertained at monthly clinic visits and unscheduled sick visits. The Andersen-Gill Cox model was used to assess maternal, environmental, and infant correlates of diarrhea, moderate-to-severe diarrhea (MSD; diarrhea with dehydration, dysentery, or related hospital admission), and prolonged/persistent diarrhea (> 7 days) in infants. HIV-exposed, uninfected infants (n = 373) experienced a mean 2.09 (95% CI: 1.93, 2.25) episodes of diarrhea, 0.47 (95% CI: 0.40, 0.55) episodes of MSD, and 0.34 (95% CI: 0.29, 0.42) episodes of prolonged/persistent diarrhea in their first year. Postpartum maternal diarrhea was associated with increased risk of infant diarrhea (Hazard ratio [HR]: 2.09; 95% CI: 1.43, 3.06) and MSD (HR: 2.89; 95% CI: 1.10, 7.59). Maternal antibiotic use was a risk factor for prolonged/persistent diarrhea (HR: 1.63; 95% CI: 1.04, 2.55). Infants living in households with a pit latrine were 1.44 (95% CI: 1.19, 1.74) and 1.49 (95% CI: 1.04, 2.14) times more likely to experience diarrhea and MSD, respectively, relative to those with a flush toilet. Current exclusive breastfeeding was protective against MSD (HR: 0.30; 95% CI: 0.15, 0.58) relative to infants receiving no breast milk. Reductions in maternal diarrhea may result in substantial reductions in diarrhea morbidity among HEU children, in addition to standard diarrhea prevention interventions.

Immune Activation and Microbial Translocation Markers in HIV-Exposed Uninfected Malawian Infants in the First Year of Life

BACKGROUND

HIV-exposed uninfected (HEU) infants show a high rate of morbidity. We aimed to investigate on biomarkers of immune activation/microbial translocation in HEU infants, evaluating the impact that infections/malnutrition can have on biomarker levels during the first year of life.

METHODS

Clinical data of 72 Malawian infants were recorded monthly and correlated with levels of soluble CD14 (sCD14), lipopolysaccharide-binding protein (LBP) and intestinal fatty acid-binding protein (I-FABP), analyzed longitudinally.

RESULTS

Levels of sCD14 and LBP showed a significant age-related increase. Higher levels of LBP (19.4 vs. 15.2 μg/ml) were associated with stunting, affecting 30% of the infants. The association remained statistically significant after adjusting for cytomegalovirus acquisition, malaria and respiratory infections (p = 0.031). I-FABP levels were significantly increased in infants experiencing gastrointestinal infections (1442.8 vs. 860.0 pg/ml, p = 0.018).

CONCLUSION

We provide evidence that stunting is associated with an enhanced inflammatory response to microbial products in HEU children, suggesting that malnutrition status should be taken into consideration to better understand the alteration of the immune profile of HEU infants living in poor socioeconomic settings.

Association between zidovudine-containing antiretroviral therapy exposure in utero and leukocyte telomere length at birth

OBJECTIVES

Zidovudine (ZDV) is a nucleoside reverse transcriptase inhibitor that could cause telomere shortening through inhibition of telomerase. We examined the association between in utero exposure to ZDV and telomere length at birth in HIV-exposed-uninfected (HEU) newborns.

METHODS

We selected 94 ZDV-exposed HEU children and 85 antiretroviral therapy (ART)-unexposed HEU children from the Surveillance Monitoring for ART Toxicities Study and the Women and Infants Transmission Study. We assessed relative telomere length in stored peripheral blood mononuclear cells taken in the first 7 days of life using quantitative polymerase chain reaction. We used linear regression to compare relative telomere length between ZDV-exposed and ART-unexposed children. We additionally evaluated relative telomere length according to maternal and infant characteristics.

RESULTS

Relative telomere length was longer in ZDV-exposed children compared with ART-unexposed individuals (adjusted mean ratio difference 0.21, 95% confidence interval 0.15-0.28, P < 0.001). We found an inverse correlation between maternal HIV RNA levels and infant relative telomere length (-0.06 per log10 copies, 95% confidence interval -0.08 to -0.03, P < 0.001). Relative telomere length was not associated with maternal CD4 cell count, maternal age, gestational age, sex, sample storage time, or maternal substance use (P > 0.05).

CONCLUSION

Relative telomere length was longer in ZDV-exposed infants. This difference may reflect beneficial health effects of ART during pregnancy, as we observed an inverse association with maternal HIV RNA levels.

Impact of maternal HIV exposure, feeding status, and microbiome on infant cellular immunity

At least one-third of infants born in sub-Saharan Africa have been exposed to the effects of maternal HIV infection and antiretroviral treatment. Intrauterine HIV exposure is associated with increased rates of morbidity and mortality in children. Although the mechanisms responsible for poor infant health with HIV-1 exposure are likely to be multifactorial, we posit that the maternal environment during gestation and in the perinatal period results in altered infant immunity and is possibly the strongest contributing factor responsible for the disproportionally high infectious events among HIV-exposed infants who remain HIV uninfected. This review provides a synthesis of studies reporting the impact of intrauterine HIV exposure, feeding practices, and microbiota on immune ontogeny in the first year of life in HIV-exposed uninfected infants.

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.

Effect of Point-of-Care Diagnostics on Maternal Outcomes in Human Immunodeficiency Virus-Infected Women: Systematic Review and Meta-analysis

INTRODUCTION

The World Health Organization advocates for increased accessibility of HIV-related point-of-care (POC) diagnostics in settings that lack laboratory infrastructure. The aim of this study is to assess the impact of POC diagnostics on maternal health outcomes in HIV-infected women.

METHODS

A systematic literature review used multiple data sources as follows: Cochrane Infectious Disease Group Specialized Register; Cochrane Central Register of Control Trials, published in The Cochrane Library; PubMed; EBSCOhost and LILACS from January 2000 to October 2015. References of included studies were hand searched. Randomized controlled trials (RCTs) and observational studies examining health outcomes of HIV-infected women were eligible for inclusion in this review. The Cochrane Risk of Bias tool was used for bias assessment of the included studies. PRISMA guidelines were used for reporting.

RESULTS

Of the 695 studies identified, six retrievable studies (five cross-sectional studies and one case control study) met the inclusion criteria and were included in this study. These studies examined a total of 167 HIV-infected women in different study settings. No studies reported evidence of CD4 count, viral load and TB, and the syphilis POC test impact on HIV-infected women was not found by this study. Included studies reported the impact of various HIV rapid tests across the following five maternal outcomes: timely receipt of results with pooled effect size (ES) = 1.00 (95% confidence interval [CI]: (0.98; 1.02); enabling partner testing, ES = 0.95 (0.85; 1.04); prevention of mother-to-child transmission of HIV, ES = 0.86 (0.79; 0.93); linkage to antiretroviral treatment (ART), ES = 0.76 (0.69; 0.84); and linkage to HIV care, ES = 0.50 (0.18; 0.82). No studies reported evidence of the impact of POC testing on maternal mortality or maternal and child morbidity of HIV-infected women.

CONCLUSIONS

The review provides an international overview of the impact of HIV POC diagnostics on maternal outcomes in HIV-infected women, showing the evidence that the HIV POC test is significantly associated with decreased mother-to-child transmission of HIV and increased linkage to ART and HIV care for HIV-infected women. It also revealed a gap in the literature aimed at assessing the impact of POC diagnostics on maternal morbidity and mortality in HIV-infected women.

Point-of-Care Diagnostics for Improving Maternal Health in South Africa

Improving maternal health is a global priority, particularly in high HIV-endemic, resource-limited settings. Failure to use health care facilities due to poor access is one of the main causes of maternal deaths in South Africa. "Point-of-care" (POC) diagnostics are an innovative healthcare approach to improve healthcare access and health outcomes in remote and resource-limited settings. In this review, POC testing is defined as a diagnostic test that is carried out near patients and leads to rapid clinical decisions. We review the current and emerging POC diagnostics for maternal health, with a specific focus on the World Health Organization (WHO) quality-ASSURED (Affordability, Sensitivity, Specificity, User friendly, Rapid and robust, Equipment free and Delivered) criteria for an ideal point-of-care test in resource-limited settings. The performance of POC diagnostics, barriers and challenges related to implementing POC diagnostics for maternal health in rural and resource-limited settings are reviewed. Innovative strategies for overcoming these barriers are recommended to achieve substantial progress on improving maternal health outcomes in these settings.

Linking Susceptibility to Infectious Diseases to Immune System Abnormalities among HIV-Exposed Uninfected Infants

HIV-exposed uninfected (HEU) infants experience increased overall mortality from infectious causes when compared to HIV-unexposed uninfected (HU) infants. This is the case in both the resource-rich and resource-limited settings. Here, we explore the concept that specific types of infectious diseases that are more common among HEU infants could provide clues as to the potential underlying immunological abnormalities. The most commonly reported infections in HEU vs. HU infants are caused by encapsulated bacteria, suggesting the existence of a less effective humoral (antibody, complement) immune response. Decreased transplacental transfer of protective maternal antibodies has consistently been observed among HEU newborns, suggesting that this may indeed be one of the key drivers of their susceptibility to infections with encapsulated bacteria. Reassuringly, HEU humoral response to vaccination appears to be well conserved. While there appears to be an increase in overall incidence of acute viral infections, no specific pattern of acute viral infections has emerged; and although there is evidence of increased chronic viral infection from perinatal transmission of hepatitis C and cytomegalovirus, no data exist to suggest an increase in adverse outcomes. Thus, no firm conclusions about antiviral effector mechanisms can be drawn. However, the most unusual of reported infections among the HEU have been opportunistic infections, suggesting the possibility of underlying defects in CD4 helper T cells and overall immune regulatory function. This may relate to the observation that the immunological profile of HEUs indicates a more activated T cell profile as well as a more inflammatory innate immune response. However, both of these observations appear transient, marked in early infancy, but no longer evident later in life. The causes of these early-life changes in immune profiles are likely multifactorial and may be related to in utero exposure to HIV, but also to increased environmental exposure to pathogens from sicker household contacts, in utero and postnatal antiretroviral drug exposure, and, in certain circumstances, differences in mode of feeding. The relative importance of each of these factors will be important to delineate in an attempt to identify those HEU at highest risk of adverse outcomes for targeted interventions.

Clinical outcomes of HIV-exposed, HIV-uninfected children in sub-Saharan Africa

OBJECTIVE

HIV-exposed but HIV-uninfected (HEU) children are widely considered at increased risk of mortality and morbidity. Recent advances in prevention of mother-to-child HIV transmission (PMTCT) strategies, incorporating life-long universal maternal antiretroviral therapy (ART, "Option B+") with extended breastfeeding, may improve HEU child health substantially. We critically reviewed reports of mortality/morbidity among HEU and HIV-unexposed (HU) children in sub-Saharan Africa.

METHODS

We searched Medline, EMBASE, CINAHL, PsycINFO, Academic Search Premier, Global Health & Psychosocial Instruments databases, conference abstracts, and reference lists for longitudinal studies from sub-Saharan Africa reporting mortality and clinical morbidity among HIV-uninfected children aged ≤10 years, by maternal HIV status. Studies were appraised by Newcastle-Ottawa Scale and ACROBAT-NRSI. Due to substantial heterogeneity of study designs, populations and results (I(2) = 75%), data were not synthesised.

RESULTS

We included 37 reports (28 studies, 11 164 HEU children); methodological and reporting quality were variable. Most reports came from settings without universal access to maternal ART (n = 35). Results were conflicting, with some studies indicating increased risk of mortality, hospitalisation and/or under-nutrition among HEU children, while others found no evidence of increased risk. In subanalyses, improved maternal health, ART use and breastfeeding were strongly protective for all outcomes. Only 39% (11/28) of studies adjusted for major confounders. Reports from settings using universal maternal ART with breastfeeding (n = 2) found no differences in growth or development but did not report mortality or infectious morbidity.

CONCLUSIONS

The existing literature provides little insight into HEU child health under recently adopted PMTCT strategies. There is a need for robust comparative data on HEU and HIV-unexposed child health outcomes under Option B+; optimising breastfeeding practices and increasing maternal use of ART should be urgent public health priorities.

Altered Memory T-Cell Responses to Bacillus Calmette-Guerin and Tetanus Toxoid Vaccination and Altered Cytokine Responses to Polyclonal Stimulation in HIV-Exposed Uninfected Kenyan Infants

Implementation of successful prevention of mother-to-child transmission of HIV strategies has resulted in an increased population of HIV-exposed uninfected (HEU) infants. HEU infants have higher rates of morbidity and mortality than HIV-unexposed (HU) infants. Numerous factors may contribute to poor health in HEU infants including immunological alterations. The present study assessed T-cell phenotype and function in HEU infants with a focus on memory Th1 responses to vaccination. We compared cross-sectionally selected parameters at 3 and 12 months of age in HIV-exposed (n = 42) and HU (n = 28) Kenyan infants. We measured ex vivo activated and bulk memory CD4 and CD8 T-cells and regulatory T-cells by flow cytometry. In addition, we measured the magnitude, quality and memory phenotype of antigen-specific T-cell responses to Bacillus Calmette-Guerin and Tetanus Toxoid vaccine antigens, and the magnitude and quality of the T cell response following polyclonal stimulation with staphylococcal enterotoxin B. Finally, the influence of maternal disease markers on the immunological parameters measured was assessed in HEU infants. Few perturbations were detected in ex vivo T-cell subsets, though amongst HEU infants maternal HIV viral load positively correlated with CD8 T cell immune activation at 12 months. Conversely, we observed age-dependent differences in the magnitude and polyfunctionality of IL-2 and TNF-α responses to vaccine antigens particularly in Th1 cells. These changes mirrored those seen following polyclonal stimulation, where at 3 months, cytokine responses were higher in HEU infants compared to HU infants, and at 12 months, HEU infant cytokine responses were consistently lower than those seen in HU infants. Finally, reduced effector memory Th1 responses to vaccine antigens were observed in HEU infants at 3 and 12 months and higher central memory Th1 responses to M. tuberculosis antigens were observed at 3 months only. Long-term monitoring of vaccine efficacy and T-cell immunity in this vulnerable population is warranted.

Exonuclease III-based target recycling for ultrasensitive homogeneous monitoring of HIV DNA using Ag(+)-coordinated hairpin probe

A new homogeneous electrochemical sensing strategy based on exonuclease III-assisted target recycling amplification was utilized for simple, rapid and highly sensitive detection of human immunodeficiency virus (HIV) DNA on an immobilization-free Ag(I)-assisted hairpin DNA through the cytosine-Ag(+)-cytosine coordination chemistry. The assay involved target-induced strand-displacement reaction accompanying dissociation of the chelated Ag(+) in the hairpins and exonuclease III-triggered target recycling. Initially, the added target DNA hybridized with hairpin DNA to disrupt the Ag(I)-coordinated hairpin probe and releases the coordinated Ag(+) ion. Then, the newly formed DNA double-stranded DNA could be cleaved by exonuclease III, and released target HIV DNA, which retriggered the strand-displacement reaction with the hairpin for target recycling, thereby resulting in formation of numerous free Ag(+) ions in the detection cell. The released Ag(+) ions can be readily captured by the negatively charged electrode, and subsequent anodic-stripping voltammetric detection of the captured Ag(+) ions are conducted to form the anodic current for the production of the electronic signal within the applied potential. Under optimal conditions, the exonuclease III-based sensing system exhibited good electrochemical responses for the detection of HIV DNA at a concentration as low as 23 fM.