Characterizing the Immune System After Long-Term Undetectable Viral Load in HIV-1-Infected Children

Thirty two HIV-infected children, on highly active antiretroviral therapy (HAART) and >500 CD4+ T cells/mm3, were rated according to the time-course of viral load (VL) during the whole follow-up period (>18 months) in a longitudinal retrospective study. (a) uVL group: 15 children with VL below 400 copies/mL; (b) dVL group: 17 children with higher VL. The uVL group showed higher memory (CD4+CD45RO+) T cells than did dVL group, and higher number of memory activated CD4+CD45RO+HLA-DR+ than did control group (healthy age-matched uninfected children), whereas CD4+CD45RAhi+CD62L+ was similar. However, TCR rearrangement excision circles (TRECs) were higher in uVL group than in dVL group. uVL Group showed CD8+CD45RO+ and CD8+CD45RO+CD38+ higher number than the control group, but lower than the dVL group. The percentage of CD8+CD45RAhi+CD62L+, CD8+CD45RA+, CD8+CD62L+, and CD8+CD28+ was higher in uVL group than in dVL group, and lower than in control group. The uVL group showed higher number of activated (HLA-DR+CD38+, HLA-DR+, HLA-DR+CD38−) CD4+ T cells and lower percentages of CD4+HLA-DR−CD38+ than dVL group. In activated CD8+ T cell, the uVL group had lower CD8+HLA-DR+CD38+, CD8+HLA-DR+, and CD8+CD38+ than the dVL group. Preeffector (CD8+CD57−CD28− and CD8+CD45RA−CD62L−) T cells were lower in the uVL group than in dVL group. In the effector (CD8+CD57+, CD8+CD57+CD28−, and CD8+CD45RA+CD62L−) T cells, HIV-infected-children had higher values than control group. HIV-infected-children who respond to HAART had TRECs reconstitution, decreased immune activation, and lower effector CD8+ T cells. Moreover, successful HAART allow the increment of activated CD4+ T cells.