CD4+ memory T cells are the predominant population of HIV-1-infected lymphocytes in neonates and children.
BACKGROUND
CD4+ memory T cells express CD45RO and are the principal viral reservoir in HIV-infected adults. In infants and children, CD45RO T cells comprise the minority of the CD4+ T-cell population. The majority of blood CD4+ T cells are naive, expressing CD45RA.


OBJECTIVE
To determine the developmental stage at which pediatric CD4+ T cells become susceptible to HIV-1 infection in vivo by determining which T-cell population harbors HIV-1 proviral DNA.


METHODS
A prospective, cross-sectional 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 reaction methods were used to detect HIV-1 proviral DNA within purified lymphocyte populations selected using immunoaffinity magnetic microspheres.


RESULTS
CD8+ T cells harbored no detectable HIV-1, indicating that infection of common thymocytes does not contribute to the population of infected blood T cells. In five children and two of the five neonates, the CD4+ CD45RO memory T lymphocytes contained 10-100-fold greater numbers of infected cells than the CD4+ CD45RA naive T-cell population. Three neonates, who exhibited rapid disease progression, demonstrated 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 small population of terminally differentiated CD4+ CD45RO memory T cells. Neonates with rapid CD4+ T-cell attrition display high levels of provirus in their CD4+ CD45RA T-cell population.
Sleasman
J W
JW
Department of Pediatrics, University of Florida College of Medicine, Gainesville 32610-0296, USA.
Aleixo
L F
LF
Morton
A
A
Skoda-Smith
S
S
Goodenow
M M
MM
D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000145:classification / Q000276:immunology* / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000821:virology; D002452:Cell Count; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D015658:HIV Infections / Q000097:blood / Q000276:immunology*; D015497:HIV-1 / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology; D007223:Infant; D007231:Infant, Newborn; D017493:Leukocyte Common Antigens / Q000276:immunology*; D011446:Prospective Studies
D004279:DNA, Viral; D017493:Leukocyte Common Antigens