Prevalence and determinants of HIV shedding in breast milk during continued breastfeeding among Zambian mothers not on antiretroviral treatment (ART): A cross-sectional study

Follow-up for 3 years of a pediatric population diagnosed in 2018 with mother-to-child transmission of HIV in 8 Latin American countries in the PLANTAIDS cohort

INTRODUCTION

The frequency of mother-to-child transmission (MTCT) of human immunodeficiency virus (HIV) in Latin America has decreased considerably. However, new infections continue to be recorded, and the pediatric population remains one of the most vulnerable groups in this region. The main objective of the study was to describe the clinical, epidemiological and psychosocial characteristics of new diagnoses of HIV MTCT in 2018 in the PLANTAIDS network (Paediatric Network for Prevention, Early Detection and Treatment of HIV in Children) during the 3 years following diagnosis.

METHODOLOGY

Retrospective, multicenter, descriptive study based on a 3-year follow-up of patients diagnosed with HIV infection due to MTCT in 2018 in 10 hospitals in 8 Latin American countries (Costa Rica, Ecuador, Mexico, Honduras, El Salvador, Panama, Guatemala and Venezuela). The hospitals belonged to the PLANTAIDS network, which is included in CYTED (Ibero-American Programme of Science and Technology for Development).

RESULTS

The study population comprised 72 pediatric patients (38.9% male). The median age at diagnosis was 2.4 years (IQR: 0.8-5.4). There were 35 cases of opportunistic infections corresponding to 25 patients (34.7%), with tuberculosis being the most common. Adequate childhood vaccination coverage was achieved in 80.5%. There were 3 cases of acute SARS-CoV-2 infection, and these were asymptomatic or mildly symptomatic. According to the Centers for Disease Control and Prevention (CDC) classification, the most frequent clinical-immunological stage at all check-ups was C1. Three patients died from opportunistic infections and/or advanced HIV infection.

CONCLUSIONS

It is important to diagnose HIV infection early in pediatrics, since early initiation of ART is associated with a decrease in mortality. Despite this, HIV infection has a poor prognosis in children, necessitating adequate follow-up to ensure adherence to health care and ART, although it can sometimes prove difficult in children.

New diagnosis of mother-to-child transmission of HIV in 8 Latin-American countries during 2018

Background

Important prevention efforts have led to a reduction in mother-to-child transmission of HIV (MTCT) globally. However, new cases of paediatric HIV infections still occur. Early diagnosis of new HIV infections is essential to start an appropriate antiretroviral treatment to avoid childhood morbidity and mortality related to infection. The aim of this study was to describe the new cases of MTCT in Latin-American referral hospitals.

Methods

A retrospective, multicentre and descriptive study of the new cases of MTCT diagnosed during 2018 in 13 referral hospitals from 8 Latin-American countries (Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, and Panama) belonging to PLANTAIDS (Paediatric Network for Prevention, Early Detection and Treatment of HIV in Children), was conducted. PLANTAIDS is included in CYTED (Ibero-American Programme of Science and Technology for Development).

Results

Eighty-one children (40.7% males) were included, median age at diagnosis of 2.33 years (IQR:0.7–4.7). Less than 3% of women knew their HIV diagnosis before pregnancy. More than 80% of them were diagnosed after delivery, 8.7% during pregnancy, and 2.9% at delivery. Only one patient underwent antiretroviral therapy (ART) prior to pregnancy. At diagnosis, 50.0% of the children presented with an advanced stage of disease (stage C following the current CDC classification for HIV infection), and 34.4% had less than 15% CD4⁺ cells/mm³. The time elapsed between delivery and the maternal diagnosis was correlated with the age of children at diagnosis, ρ = 0.760, p < 0.001. Younger age at diagnosis (p = 0.03), a smaller number of previous hospitalizations (p < 0.01), and better immunovirological status (p < 0.01) were found in children whose mothers knew their HIV status at delivery, compared to mothers who were not aware of it.

Conclusions

Although MTCT in Latin America has declined in recent years, our series shows there are still cases that indicate some failures in prevention, being a critical point to improve an earlier diagnosis of pregnant women. Half of the children were diagnosed in an advanced stage of disease and the delay in maternal diagnosis entailed a worse clinical and immunological child’ prognosis.

Recurrent Severe Subclinical Mastitis and the Risk of HIV Transmission Through Breastfeeding

Subclinical mastitis (SCM) is an important risk factor of postnatal HIV-1 transmission that is still poorly understood. A longitudinal sub-study of the ANRS12174 trial including 270 breastfeeding mothers in Lusaka, Zambia measured sodium (Na⁺) and potassium (K⁺) in archived paired breast milk samples collected at week 14, 26 and 38 postpartum to determine cumulative incidence of SCM and the effects of recurrent severe SCM on HIV-1 shedding in breast milk. A nested retrospective cohort study including 112 mothers was also done to determine longitudinal effects of SCM on four pro-inflammatory cytokines; IL6, IL8, IP10 and RANTES. The cumulative incidence for any SCM (Na⁺/K⁺ ratio > 0.6) and severe SCM (Na⁺/K⁺ ratio > 1) were 58.6% (95%CI: 52.7 – 64.5) and 27.8% (95%CI: 22.5 – 33.1), respectively. In majority of affected mothers (51.4%) severe SCM was recurrent. Both breasts were involved in 11.1%, 33.3% and 70% of the mothers with a single episode, 2 and 3 episodes respectively. In affected breasts, an episode of severe SCM resulted in steep upregulation of the four cytokines considered (IL8, IP10, RANTES and IL6) compared to: before and after the episode; contralateral unaffected breasts; and SCM negative control mothers. Recurrent severe SCM significantly increased the odds of shedding cell-free HIV-1 in breast milk (OR: 5.2; 95%CI: 1.7 – 15.6) whereas single episode of severe SCM did not (OR: 1.8; 95%CI: 0.8 – 4.2). A Na⁺/K⁺ ratio > 1 indicative of severe SCM is an excellent indicator of breast inflammation characterized by a steep, localized and temporal upregulation of several pro-inflammatory cytokines that favor HIV-1 shedding in mature breast milk and may facilitate postnatal HIV-1 transmission through breastfeeding.

The CD133+ Stem/Progenitor-Like Cell Subset Is Increased in Human Milk and Peripheral Blood of HIV-Positive Women

Human milk is a significant source of different CD133⁺ and/or CD34⁺ stem/progenitor-like cell subsets in healthy women but their cell distribution and percentages in this compartment of HIV-positive women have not been explored. To date, a decrease of CD34⁺ hematopoietic stem and progenitor cell frequencies in peripheral blood and bone marrow of HIV-positive patients has been reported. Herein, human milk and peripheral blood samples were collected between day 2–15 post-partum from HIV-positive and HIV-negative women, and cells were stained with stem cell markers and analyzed by flow cytometry. We report that the median percentage of CD45^+/highCD34⁻CD133⁺ cell subset from milk and blood was significantly higher in HIV-positive than in HIV-negative women. The percentage of CD45^dimCD34⁻CD133⁺ cell subset from blood was significantly higher in HIV-positive than HIV-negative women. Moreover, percentages of CD45^dimCD34⁺, CD45^dimCD34⁺CD133⁻, and CD45^+highCD34⁺CD133⁻ cell subsets from blood were significantly lower in HIV-positive than HIV-negative women. The CD133⁺ stem/progenitor-like cell subsets are increased in early human milk and blood of HIV-positive women and are differentially distributed to CD34⁺ cell subset frequencies which are decreased in blood.