title: Immunologic targets of HIV infection: T cells. NICHD IVIG Clinical Trial Group, and the NHLBI P2C2 Pediatric Pulmonary and Cardiac Complications of HIV Infection Study Group.
abstract: One of the principal targets of HIV infection is the human peripheral blood CD4+ T cell, resulting in progressive CD4+ lymphocyte loss. Hypothesized mechanisms for this loss include apoptosis, cytolytic reactions, V-beta gene deletion of the T-cell receptor (TCR) by superantigens, CD4+ lymphocyte syncytium formation, and autoimmune reactions. In adults with HIV infection, the critical decline in CD4+ lymphocyte number that heralds the onset of AIDS-defining conditions is well characterized, whereas in infants and children the critical level of CD4+ cells predisposing to the development of AIDS-defining conditions or mortality is not fully characterized, due to an incomplete knowledge of CD4+ lymphocyte number and changes with age in normal and HIV-infected children. In a prospective study of 317 infants born to HIV-infected women, early results show that the monthly change in absolute CD4+ lymphocyte number over a 3- to 9-month period in HIV-infected infants was -109 cells/mm3 per month, at least double the rate of decline measured in HIV-noninfected infants in the study or that calculated from normal infants' values reported in the literature. In other clinical studies in HIV-infected infants and children, it was possible to study the effect of low CD4+ cell counts on clinical status and mortality. In HIV-infected pediatric patients younger than 1 year, it was possible to correlate low CD4+ cell number with advanced disease status (CDC pediatric class P-2). It was also possible to correlate extremely low CD4+ cell counts (< 200 cells/mm3) in HIV-infected children with a significant risk of mortality within the next 3 months of life. Sequential CD4+ cell analysis of HIV-high-risk infants will delineate the rate of HIV-related decline in CD4+ cells, thus facilitating the diagnosis of HIV infection and aiding in identification of HIV-infected children at high risk of disease progression or death.
authors.affiliation: Department of Allergy & Immunology, Texas Children's Hospital, Houston 77030.
authors.forename: W T
authors.initials: WT
authors.lastname: Shearer
authors.forename: H M
authors.initials: HM
authors.lastname: Rosenblatt
authors.forename: M D
authors.initials: MD
authors.lastname: Schluchter
authors.forename: L M
authors.initials: LM
authors.lastname: Mofenson
authors.forename: T N
authors.initials: TN
authors.lastname: Denny
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D015658:HIV Infections / Q000276:immunology* / Q000401:mortality; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007958:Leukocyte Count