Mother-to-child transmission of HIV-1: Timing and implications for prevention
Columbia University, New York, New York, United States The Lancet Infectious Diseases
(Impact Factor: 22.43).
12/2006; 6(11):726-32. DOI: 10.1016/S1473-3099(06)70629-6
This article provides a synthesis of clinical trial data with an aim to deduce the timing of mother-to-child transmission of HIV-1. Because transmission of the infection to the infant through breastfeeding is one of the main challenges in fighting paediatric HIV/AIDS in the developing world, we present separate estimates for the timing of HIV transmission for non-breastfeeding and breastfeeding populations. Our estimates predict that, for non-breastfeeding populations, 50% of HIV infections are transmitted to the infant at the very end of pregnancy, near to the time of labour. For breastfeeding populations, the postnatal period accounts for most of the HIV infections transmitted to the infant. We discuss the potential benefit of exclusive breastfeeding for the first 6 months of life as a policy to decrease the magnitude of HIV transmission. Furthermore, we present the hypothesis, based on recent research findings of viral latency, that the time when a fetus initially encounters the virus might not be when infection is established. We discuss the implications of this hypothesis and how it could lead to new interventions for the prevention of mother-to-child HIV transmission.
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- "In 30%-50% of cases, transmission occurs at the end of pregnancy, immediately before labor starts and immediately before the separation of the placenta. In approximately 30% of cases, transmission occurs after the desquamation of the placenta, when the baby is passing through the birth canal12). There is a 40% risk of infection when consuming contaminated breast milk13). "
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ABSTRACT: Administration of antiretroviral drugs to mothers and infants significantly decreases mother-to-child human immunodeficiency virus (HIV) transmission; cesarean sections and discouraging breastfeeding further decreases this risk. The present study confirmed the HIV status of babies born to mothers infected with HIV and describes the characteristics of babies and mothers who received preventive treatment.
This study retrospectively analyzed medical records of nine infants and their mothers positive for HIV who gave birth at Korea University Ansan Hospital, between June 1, 2003, and May 31, 2013. Maternal parameters, including HIV diagnosis date, CD4+ count, and HIV ribonucleic acid (RNA) copy number, were analyzed. Infant growth and development, HIV RNA copy number, and HIV antigen/antibody test results were analyzed.
Eight HIV-positive mothers delivered nine babies; all the infants received antiretroviral therapy. Three (37.5%) and five mothers (62.5%) were administered single- and multidrug therapy, respectively. Intravenous zidovudine was administered to four infants (50%) at birth. Breastfeeding was discouraged for all the infants. All the infants were negative for HIV, although two were lost to follow-up. Third trimester maternal viral copy numbers were less than 1,000 copies/mL with a median CD4+ count of 325/µL (92-729/µL). Among the nine infants, two were preterm (22.2%) and three had low birth weights (33.3%).
This study concludes that prophylactic antiretroviral therapy, scheduled cesarean section, and prohibition of breastfeeding considerably decrease mother-to-child HIV transmission. Because the number of infants infected via mother-to-child transmission may be increasing, studies in additional regions using more variables are necessary.
Available from: plosone.org
- "Known maternal risk factors associated with MTCT are high plasma viral loads, low CD4 T-cell numbers coinciding with advanced maternal immune deficiency and prolonged labor . In populations where replacement feeding is not feasible it has been estimated that 41% of MTCT occur in utero (IU), 20% peri-partum (PP) and the remaining 39% during prolonged breastfeeding (BF) . The majority of transmissions are found in regions where antiretroviral therapy availability is limited, such as sub-Saharan Africa (UNAIDS Progress report 2011) and specifically regions where HIV-1 subtype A and C predominate, including the growing number of infections in Russia . "
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ABSTRACT: The HIV-1 characteristics associated with mother to child transmission (MTCT) are still poorly understood and if known would indicate where intervention strategies should be targeted. In contrast to horizontally infected individuals, exposed infants possess inherited antibodies (Abs) from their mother with the potential to protect against infection. We investigated the HIV-1 gp160 envelope proteins from seven transmitting mothers (TM) whose children were infected either during gestation or soon after delivery and from four non-transmitting mothers (NTM) with similar viral loads and CD4 counts. Using pseudo-typed viruses we tested gp160 envelope glycoproteins for TZM-bl infectivity, CD4 and CCR5 interactions, DC-SIGN capture and transfer and neutralization with an array of common neutralizing Abs (NAbs) (2F5, 2G12, 4E10 and b12) as well as mother and infant plasma. We found no viral correlates associated with HIV-1 MTCT nor did we find differences in neutralization with the panel of NAbs. We did, however, find that TM possessed significantly higher plasma neutralization capacities than NTM (P = 0.002). Furthermore, we found that in utero (IU) TM had a higher neutralization capacity than mothers transmitting either peri - partum (PP) or via breastfeeding (BF) (P = 0.002). Plasma from children infected IU neutralized viruses carrying autologous gp160 viral envelopes as well as those from their corresponding mothers whilst plasma from children infected PP and/or BF demonstrated poor neutralizing capacity. Our results demonstrate heightened autologous NAb responses against gp120/gp41 can associate with a greater risk of HIV-1 MTCT and more specifically in those infants infected IU. Although the number of HIV-1 transmitting pairs is low our results indicate that autologous NAb responses in mothers and infants do not protect against MTCT and may in fact be detrimental when considering IU HIV-1 transmissions.
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- "Maternofetal transmission (MFT) of HIV-1 is relatively rare, even in the absence of antiretroviral therapy. R5 HIV-1 isolates are found in most cases of mother-to-child transmission [11-16], and MFT usually occurs during the last trimester  pointing to the existence of effective natural control mechanisms particularly during the first months of pregnancy. During the first trimester of pregnancy the maternofetal interface is composed of the placenta (the fetal part) and the maternal uterine mucosa (decidua) . "
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ABSTRACT: Maternofetal transmission (MFT) of HIV-1 is relatively rare during the first trimester of pregnancy despite the permissivity of placental cells for cell-to-cell HIV-1 infection. Invasive placental cells interact directly with decidual cells of the uterine mucosa during the first months of pregnancy, but the role of the decidua in the control of HIV-1 transmission is unknown.
We found that decidual mononuclear cells naturally produce low levels of IL-10, IL-12, IL-15, TNF-α, IFN-α, IFN-γ and CXCL-12 (SDF-1), and large amounts of CCL-2 (MCP1), CCL-3 (MIP-1α), CCL-4 (MIP-1β), CCL-5 (Rantes), CXCL-10 (IP-10), IL-6 and IL-8. CCL-3 and CCL-4 levels were significantly upregulated by in vitro infection with R5 HIV-1 but not X4. Decidual CD14+ antigen presenting cells were the main CCL-3 and CCL-4 producers among decidual leukocytes. R5 and X4 HIV-1 infection was inhibited by decidual cell culture supernatants in vitro. Using HIV-1 pseudotypes, we found that inhibition of the HIV-1 entry step was inhibited by decidual soluble factors.
Our findings show that decidual innate immunity (soluble factors) is involved in the control of HIV-1 infection at the maternofetal interface. The decidua could thus serve as a mucosal model for identifying correlates of protection against HIV-1 infection.
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