CD4-CELLS ARE THE PREDOMINANT POPULATION OF HIV-1-INFECTED LYMPHOCYTES IN NEONATES AND CHILDREN( MEMORY T)

Background: CD4+ memory T cells express CD45RO and are the principal v iral reservoir in HIV-infected adults. In infants and children, CD45RO T cells comprise the minority of the CD4+ T-cell population. The majo rity of blood CD4+ T cells are naive, expressing CD45RA. Objective: To determine the developmental stage at which pediatric CD4+ T cells bec ome susceptible to HIV-1 infection in vivo by determining which T-cell population harbors HIV-1 proviral DNA. Design: A prospective, cross-s ectional analysis of peripheral blood CD8+ T cells, CD45RA, or CD45RO CD4+ T cells obtained from 10 HIV-infected neonates and children were analysed for provirus. Methods: Semi-quantitative polymerase chain rea ction methods were used to detect HIV-1 proviral DNA within purified l ymphocyte populations selected using immunoaffinity magnetic microsphe res. Results: CD8+ T cells harbored no detectable HIV-I, indicating th at infection of common thymocytes does not contribute to the populatio n of infected blood T cells. In five children and two of the five neon ates, the CD4+ CD45RO memory T lymphocytes contained 10-100-fold great er numbers of infected cells than the CD4+ CD45RA naive T-cell populat ion. Three neonates, who exhibited rapid disease progression, demonstr ated high proviral levels in their CD4+ CD45RA T cells. The normal age related predominance of CD4+ CD45RA T cells was preserved independent of CD4+ T-cell attrition. Conclusions: The majority of HIV-1-infected blood CD4+ T cells in infants and children are restricted to the smal l population of terminally differentiated CD4+ CD45RO memory T cells. Neonates with rapid CD4+ T-cell attrition display high levels of provi rus in their CD4+ CD45RA T-cell population.