Understanding Viral and Immune Interplay During Vertical Transmission of HIV: Implications for Cure

Pediatric immunotherapy and HIV control

PURPOSE OF REVIEW

Highlighting opportunities/potential for immunotherapy by understanding dynamics of HIV control during pediatric HIV infection with and without antiretroviral therapy (ART), as modeled in Simian immunodeficiency virus (SIV) and Simian-human immunodeficiency virus (SHIV)-infected rhesus macaques and observed in clinical trials. This review outlines mode of transmission, pathogenesis of pediatric HIV, unique aspects of the infant immune system, infant macaque models and immunotherapies.

RECENT FINDINGS

During the earliest stages of perinatal HIV infection, the infant immune system is characterized by a unique environment defined by immune tolerance and lack of HIV-specific T cell responses which contribute to disease progression. Moreover, primary lymphoid organs such as the thymus appear to play a distinct role in HIV pathogenesis in children living with HIV (CLWH). Key components of the immune system determine the degree of viral control, targets for strategies to induce viral control, and the response to immunotherapy. The pursuit of highly potent broadly neutralizing antibodies (bNAbs) and T cell vaccines has revolutionized the approach to HIV cure. Administration of HIV-1-specific bNAbs, targeting the highly variable envelope improves humoral immunity, and T cell vaccines induce or improve T cell responses such as the cytotoxic effects of HIV-1-specific CD8+ T cells, both of which are promising options towards virologic control and ART-free remission as evidenced by completed and ongoing clinical trials.

SUMMARY

Understanding early events during HIV infection and disease progression in CLWH serves as a foundation for predicting or targeting later outcomes by harnessing the immune system's natural responses. The developing pediatric immune system offers multiple opportunities for specific long-term immunotherapies capable of improving quality of life during adolescence and adulthood.

Pathogenesis of viral infections during pregnancy

SUMMARYViral infections during pregnancy are associated with significant adverse perinatal and fetal outcomes. Pregnancy is a unique immunologic and physiologic state, which can influence control of virus replication, severity of disease, and vertical transmission. The placenta is the organ of the maternal-fetal interface and provides defense against microbial infection while supporting the semi-allogeneic fetus via tolerogenic immune responses. Some viruses, such as cytomegalovirus, Zika virus, and rubella virus, can breach these defenses, directly infecting the fetus and having long-lasting consequences. Even without direct placental infection, other viruses, including respiratory viruses like influenza viruses and severe acute respiratory syndrome coronavirus 2, still cause placental damage and inflammation. Concentrations of progesterone and estrogens rise during pregnancy and contribute to immunological adaptations, placentation, and placental development and play a pivotal role in creating a tolerogenic environment at the maternal-fetal interface. Animal models, including mice, nonhuman primates, rabbits, and guinea pigs, are instrumental for mechanistic insights into the pathogenesis of viral infections during pregnancy and identification of targetable treatments to improve health outcomes of pregnant individuals and offspring.

Knowledge of HIV transmission during pregnancy among women of reproductive age in Ghana

INTRODUCTION

Human immunodeficiency virus (HIV) remains a significant health challenge affecting many people including those from sub-Saharan Africa (SSA). Even though HIV can be transmitted through various means, mother-to-child transmission (MTCT) remains the major route of transmission in children under the age of five. This study examined the correlates of knowledge of HIV transmission during pregnancy among reproductive-age women in Ghana.

METHODS

Data for this study were obtained from the 2014 Ghana Demographic and Health Survey. The sample consisted of 9,106 women aged 15 to 49 years. We conducted both descriptive and multivariable logistic regression analyses to determine the prevalence and factors associated with knowledge of HIV transmission during pregnancy. The results were presented using frequencies, percentages, and adjusted odds ratios (aOR) with their corresponding 95% confidence intervals (CI).

RESULTS

Approximately, 69.41% of women of reproductive age knew of HIV transmission during pregnancy. Women who had two (aOR = 1.32, 95% CI [1.01, 1.72]) or three (aOR = 1.37, 95% CI [1.07, 1.76]) births were more knowledgeable of HIV transmission during pregnancy. Women who read the newspaper (aOR = 1.56, 95% CI [1.31, 1.86]), listened to the radio (aOR = 1.23, 95% CI [1.05, 1.45]), lived in rural areas (aOR = 1.30, 95% CI [1.09, 1.54]) or ever been tested for HIV (aOR = 1.20, 95% CI [1.05, 1.37]) were more likely to be knowledgeable of HIV transmission during pregnancy than their counterparts in the reference categories. Compared to those in the Western Region, women in the Upper East (aOR = 0.45, 95% CI [0.32, 0.63]), Upper West (aOR = 0.54, 95% CI [0.35, 0.85]), Ashanti (aOR = 0.75, 95% CI [0.58, 0.97]) and Greater Accra Regions (aOR = 0.74, 95% CI [0.56, 0.98]) were less knowledgeable of HIV transmission during pregnancy.

CONCLUSIONS

The study highlights a gap in the knowledge of HIV transmission during pregnancy among women in Ghana. Continuous public education is required to educate women on HIV transmission from mothers to their children during pregnancy and how this may be interrupted. Such programs should involve the use of the media and take into consideration the demographic and geographic characteristics highlighted as determinants in this study. This will ultimately contribute to the reduction of MTCT of HIV in Ghana.

Lipid nanoparticle structure and delivery route during pregnancy dictate mRNA potency, immunogenicity, and maternal and fetal outcomes

Treating pregnancy-related disorders is exceptionally challenging because the threat of maternal and/or fetal toxicity discourages the use of existing medications and hinders new drug development. One potential solution is the use of lipid nanoparticle (LNP) RNA therapies, given their proven efficacy, tolerability, and lack of fetal accumulation. Here, we describe LNPs for efficacious mRNA delivery to maternal organs in pregnant mice via several routes of administration. In the placenta, our lead LNP transfected trophoblasts, endothelial cells, and immune cells, with efficacy being structurally dependent on the ionizable lipid polyamine headgroup. Next, we show that LNP-induced maternal inflammatory responses affect mRNA expression in the maternal compartment and hinder neonatal development. Specifically, pro-inflammatory LNP structures and routes of administration curtailed efficacy in maternal lymphoid organs in an IL-1β-dependent manner. Further, immunogenic LNPs provoked the infiltration of adaptive immune cells into the placenta and restricted pup growth after birth. Together, our results provide mechanism-based structural guidance on the design of potent LNPs for safe use during pregnancy.

Age at ART initiation and proviral reservoir size in perinatal HIV-1 infection: considerations for ART-free remission

PURPOSE OF REVIEW

Achieving ART-free remission without the need for lifelong antiretroviral treatment (ART) is a new objective in HIV-1 therapeutics. This review comprehensively examines the literature to evaluate whether the age at ART initiation in children with perinatal HIV-1 influences the size and decay of the HIV-1 reservoir. The insights gathered from this review serve to inform the field on the unique dynamics of HIV-1 reservoir size in perinatal HIV-1 infection as a function of age at ART initiation, as well as inform biomarker profiling and timing of ART-free remission strategies for children living with HIV-1 globally.

RECENT FINDINGS

Recent studies demonstrate that initiating very early effective ART in neonates is feasible and limits HIV-1 reservoir size. The clinical relevance of limiting the HIV-1 reservoir size in perinatal infection was recently demonstrated in the Tatelo Study, which investigated a treatment switch from ART to two broadly neutralizing antibodies (bNAbs) in very early treated children. Low proviral reservoir size was associated with sustained virologic control for 24 weeks on bNAbs.

SUMMARY

Immediate and early ART initiation for neonates and infants with perinatal HIV-1 is essential to restricting HIV-1 reservoir size that may enable ART-free remission.

Factors associated with vertical transmission of HIV in the Western Cape, South Africa: a retrospective cohort analysis

INTRODUCTION

Monitoring mother-infant pairs with HIV exposure is needed to assess the effectiveness of vertical transmission (VT) prevention programmes and progress towards VT elimination.

METHODS

We used routinely collected data on infants with HIV exposure, born May 2018-April 2021 in the Western Cape, South Africa, with follow-up through mid-2022. We assessed the proportion of infants diagnosed with HIV at birth (≤7 days), 10 weeks (>1 to 14 weeks) and >14 weeks as proxies for intrauterine, intrapartum/early breastfeeding and late breastfeeding transmission, respectively. We used mixed-effects Poisson regression to assess factors associated with VT in mothers known with HIV by delivery.

RESULTS

We included 50,461 infants born to mothers known with HIV by delivery. HIV was diagnosed in 894 (1.8%) infants. Among mothers, 51% started antiretroviral treatment (ART) before and 27% during pregnancy; 17% restarted during pregnancy after ≥6 months interruption; and 6% had no recorded ART during pregnancy. Most pregnancy ART regimens included non-nucleoside reverse transcriptase inhibitors (83%). Of mothers with available results (90% with viral load [VL]; 70% with CD4), VL nearest delivery was <100 copies/ml in 78% and CD4 count ≥350 cells/μl in 62%. HIV-PCR results were available for 86%, 67% and 48% of eligible infants at birth, 10 weeks and >14 weeks. Among these infants, 0.9%, 0.4% and 1.5% were diagnosed positive at birth, 10 weeks and >14 weeks, respectively. Among infants diagnosed with HIV, 43%, 16% and 41% were diagnosed at these respective time periods. Among mothers with VL<100, 100-999, 1000-99,000 and ≥100,000 copies/ml nearest delivery, infant HIV diagnosis incidence was 0.4%, 2.3%, 6.6% and 18.4%, respectively. Increased VT was strongly associated with recent elevated maternal VL with a seven-fold increased rate with even modestly elevated VL (100-999 vs. <100 copies/ml). VT was also associated with unknown/low maternal CD4, maternal age <20 years, no antenatal ART, later maternal ART start/restart in pregnancy and ART gaps.

CONCLUSIONS

Despite high maternal ART coverage and routine postnatal prophylaxis, ongoing VT remains a concern. Timing of infant HIV diagnoses suggests intrapartum and/or breastfeeding transmission in nearly 60%. Interventions to ensure retention on ART and sustained maternal viral suppression are needed to reduce VT.

An Atypical Presentation of Burkitt Lymphoma Presenting As Large Intra-abdominal Masses Compressing Multiple Organs With Peri-Pericardial Involvement in an HIV Patient: A Case Report and Literature Review

Many types of malignancies have been associated with immunodeficiency states, especially patients who are HIV positive. Burkitt lymphoma (BL) is one of those malignancies associated with HIV and it presents in three varieties. The endemic form is primarily seen in children, and it is associated with the Epstein-Barr virus (EBV). In this form, patients with Burkitt's present with a large jaw mass. The second variety is seen in older adults. These patients usually present with abdominal and pelvic masses. This subtype is more prominent in the United States. The third variety of BL is seen in patients who are HIV positive. In this case report, we present an atypical presentation of BL secondary to undiagnosed HIV/AIDS with a very large tumor burden causing compressive symptoms. This case will further guide healthcare professionals in diagnosing BL, which presents uniquely in high-risk populations. This report will also serve as a review of the diagnosis and treatment options of BL.

Prevention of the Vertical Transmission of HIV; A Recap of the Journey so Far

In 1989, one in four (25%) infants born to women living with HIV were infected; by the age of 2 years, there was 25% mortality among them due to HIV. These and other pieces of data prompted the development of interventions to offset vertical transmission, including the landmark Pediatric AIDS Clinical Trial Group Study (PACTG 076) in 1994. This study reported a 67.5% reduction in perinatal HIV transmission with prophylactic antenatal, intrapartum, and postnatal zidovudine. Numerous studies since then have provided compelling evidence to further optimize interventions, such that annual transmission rates of 0% are now reported by many health departments in the US and elimination has been validated in several countries around the world. Despite this success, the elimination of HIV’s vertical transmission on the global scale remains a work in progress, limited by socioeconomic factors such as the prohibitive cost of antiretrovirals. Here, we review some of the key trials underpinning the development of guidelines in the US as well as globally, and discuss the evidence through a historic lens.

Prevalence of HIV, syphilis, and hepatitis B and C virus infections in pregnant women: A systematic review and meta-analysis

BACKGROUND

At the 74th World Health Assembly, the World Health Organization (WHO) issued a strategy for the prevention and control of several major infectious diseases. To achieve the WHO-initiated targets for these infectious diseases, the elimination of mother-to-child transmission is essential. To date, a systematic review of the global and regional prevalence of infections with relevant mother-to-child transmission and outside the spectrum of congenital infections is lacking.

OBJECTIVES

We aimed to systematically review the prevalence of HIV, HBV, HCV and syphilis in pregnant women.

DATA SOURCES

MEDLINE, Embase, The Cochrane Library, Web of Science, China National Knowledge Infrastructure, WanFang database and China Biology Medicine disc database, and five WHO Regional Index Medicus databases.

STUDY ELIGIBILITY CRITERIA

Original studies reporting the prevalence of infection or co-infection of HIV, HBV, HCV and syphilis in pregnant women.

METHODS

This systematic review was followed the PRISMA 2020 checklist. We used random-effects models to generate pooled prevalence estimates for each infection.

RESULTS

Global pooled prevalence in pregnant women of HIV, HBV, HCV, and syphilis was 2.9% (95%CI 2.5-3.5%), 4.7% (3.8-5.7%), 1.0% (0.8-1.3%), and 0.8% (0.7-0.9%). The pooled prevalence of HIV, HBV, HCV, and syphilis in low-income countries was higher than the global level (HIV: 5.2% (1.6-10.5%); HBV: 6.6% (5.4-7.9%); HCV: 2.7% (1.6-4.1%); syphilis: 3.3% (2.2-4.6%)). The pooled prevalence of HIV, HBV, HCV, and syphilis in lower-middle-income countries was higher than the global level (HIV: 2.9% (0.8-6.1%); HBV: 4.9% (3.8-6.1%); HCV: 2.3% (1.2-3.6%); syphilis: 1.5% (1.0-2.2%)).

CONCLUSIONS

The prevalence of these infections among pregnant women was particularly high in resource-poor settings. The relevance and feasibility of current global practice guidelines for prevention of mother-to-child transmission of these infections for lower-middle-income countries must be evaluated, including timely access to screening and therapeutics.

Roadmap for Achieving Universal Antiretroviral Treatment

Modern antiretroviral therapy safely, potently, and durably suppresses human immunodeficiency virus (HIV) that, if left untreated, predictably causes acquired immunodeficiency syndrome (AIDS), which has been responsible for tens of millions of deaths globally since it was described in 1981. In one of the most extraordinary medical success stories in modern times, a combination of pioneering basic science, innovative drug development, and ambitious public health programming resulted in access to lifesaving, safe drugs, taken as an oral tablet daily, for most of the world. However, substantial challenges remain in the fields of prevention, timely access to diagnosis, and treatment, especially in pediatric and adolescent patients. As HIV-positive adults age, treating their comorbidities will require understanding the course of different chronic diseases complicated by HIV-related and antiretroviral toxicities and finding potential treatments. Finally, new long-acting antiretrovirals on the horizon promise exciting new options in both the prevention and treatment fields.

Getting to under 1% vertical HIV transmission: lessons from a breastfeeding cohort in South Africa

We report here on the transmission of HIV in a cohort of breastfeeding infants enrolled in a prevention of mother to child HIV transmission (PMTCT) programme at the epicentre of the HIV pandemic. South Africa implemented option B+ for PMTCT in 2015. Between 2013 and 2018, we enrolled 1219 infants born to HIV positive women into a non-inferiority trial assessing the current cotrimoxazole prophylaxis guidelines for HIV-exposed uninfected infants. Breastfeeding mothers and infants were enrolled and followed up at one of two clinics in eThekwini, KwaZulu-Natal, until 12 months of age. During the study period, 8 infants seroconverted (<1% transmission); these were likely four birth transmissions and four breastfeeding transmissions. It is critical in the post option B era to assess the reasons for vertical transmission of HIV to enable healthcare workers and policy makers to provide strategies to mitigate future infections. This report details the possible contributors to vertical transmission in this cohort and highlights the continued strategies that should be employed to further our goal towards reaching the elimination of mother to child HIV transmission