Association of selected phenotypic markers of lymphocyte activation and differentiation with perinatal human immunodeficiency virus transmission and infant infection

This study of a subset of women and infants participating in National Institutes of Health Pediatric AIDS Clinical Trials Group protocol 185 evaluated lymphocyte phenotypic markers of immune activation and differentiation to determine their association with the likelihood of human immunodeficiency virus (HIV) transmission from the women to their infants and the potential for early identification and/or prognosis of infection in the infants. Lymphocytes from 215 human immunodeficiency virus type 1 (HIV)-infected women and 192 of their infants were analyzed by flow cytometry with an extended three-color panel of monoclonal antibodies. Women who did not transmit to their infants tended to have higher CD4⁺ T cells. Most notably, levels of total CD8 ⁺ T cells and CD8⁺ CD38⁺ cells made significant independent contributions to predicting the risk of mother-to-child transmission. Adjusting for HIV-1 RNA level at entry, a one percentage-point increase in these marker combinations was associated with a nine percent increase in the likelihood of maternal transmission. Total as well as naïve CD4⁺ T cells were significantly higher in uninfected than infected infants. Total CD8⁺ cells, as well as CD8⁺ cells positive for HLA-DR⁺, CD45 RA⁺ HLA-DR⁺, and CD28 ⁺ HLA-DR⁺ were elevated in infected infants. Detailed immunophenotyping may be helpful in predicting which pregnant HIV-infected women are at increased risk of transmitting HIV to their infants. Increasing differences in lymphocyte subsets between infected and uninfected infants became apparent as early as six weeks of age. Detailed immunophenotyping may be useful in supporting the diagnosis of HIV infection in infants with perinatal HIV exposure.