Naïve and memory CD4+ T cells and T cell activation markers in HIV-1 infected children on HAART.

The objective of this study was to investigate the relationship between peripheral blood CD4+ T cell subsets and routine viro-immunological markers in vertically HIV-1-infected children undergoing highly active antiretroviral therapy (HAART). CD4+ and CD8+ T cell subsets were examined by three-colour flow cytometry. Plasma viraemia was quantified by a standardized molecular assay. A negative correlation between the %CD4+ T cells and both viral load and the %CD8+ T cells was observed. A strong positive correlation between the %CD4 T cells and naïve, CD38+ and non-activated CD4+ T cell subsets was found, whereas the %CD4 T cells correlated negatively with the numbers of memory, activated and memory-activated CD4+ T cell subsets. Elevated percentages of CD8 T cells were associated with increased memory and CD4+ CD62L-T cell subsets, whereas the naïve and CD4+ HLA-DRCD38+ subsets negatively correlated with the CD8%. Co-expression of CD62L on memory CD4+ cells and high expression of HLA-DR (but not of CD38) were associated with high viral load. No association between viral load and naïve CD4+ T cells was observed. Specific CD4+ T cell subsets may be more informative than routine surrogate markers in defining the evolution of HIV infection and immune reconstitution in children.