HIV

Human Immunodeficiency Virus

  • Dr. Lohman-Payne’s team is particularly interested in understanding how in utero Human Immunodeficiency Virus (HIV) exposure affects the immune system in early life. Dr. Lohman-Payne has long-standing collaborations with investigators at the University of Nairobi and University of Washington where a groundbreaking randomized controlled trial was conducted that determined the risk of HIV acquisition attributable to breast milk and that, despite ingestion of gallons of HIV-infected milk, 70% of breastfeeding infants remain HIV uninfected, even in the absence of antiretroviral therapy. As availability of antiretroviral treatment increases globally, more HIV-1 infected women will have access to drugs to prevent mother-to-child transmission and the numbers of HIV-1 exposed uninfected (HIV EU) children will continue to increase.

    HIV EU infants make up a unique population within the broader category of HIV exposed individuals. The majority of HIV EU individuals are adults and who remain persistently HIV seronegative after repeated exposure to HIV-1 from their seropositive partner or from commercial sex work. HIV EU infants, in contrast, have prolonged antigen exposure in utero to maternal HIV as well as to other chronic infectious diseases such as cytomegalovirus, tuberculosis and malaria. This in utero exposure is concomitant with thymic T cell development. After birth, the infant is immunized with a series of standardized vaccines, and exposed to a wide array of environmental antigens. Infants born to HIV-1 infected women are at increased risk of morbidity and mortality the first years of life compared to infants born to HIV uninfected women. What component of this increased risk is due to being born into an HIV-affected household, and how much is due to immunologic modeling in utero is the subject of continued research in the LVIP lab.

    One avenue of our translational research aims to determine the impact of in utero HIV-1 exposure on infant immunity to vaccinations and co-infections by dissecting the infant immune repertoire present at birth in the context of maternal HIV-1 infection and how the infant T cell repertoire changes following early life exposures compared to infants born to the HIV-1 uninfected women of similar socio-economic status. Infant T cell repertoire analysis combines quantitative PCR to determine relative frequency of T cell receptor β chain families with deep sequencing of the CDR3 region to evaluate clonal diversity within each family. Potential correlates of TCR diversity under evaluation include the cytokine milieu and T cell activation state present at birth and the early responses to birth vaccines.

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