Rainwater-Lovett K, Hc N, Mubiana-Mbewe M, Moore C B, Jb M, Wj M.
Increased exposure to a broad array of pathogens in children residing in sub-Saharan Africa may lead to heightened immune activation and increased proportions of memory T cells. Changes in the size of these cellular subsets have implications for restoration of normal immune function after treatment with HAART and are not well-characterized in young sub-Saharan African children.
CD4 and CD8 T cell subsets were measured by flow cytometry in 157 HIV-infected Zambian children before and at 3-month intervals during HAART for up to 30 months and in 34 control children at a single study visit.
Prior to HAART, HIV-infected children had higher levels of activated and effector memory (EM) CD4 and CD8 T cells, and lower levels of naïve T cells and CD8 T cells expressing IL-7Rα, compared to control children. The median duration of follow-up was 14.9 months (IQR: 6.4, 23.2) among 120 HIV-infected children with at least one study follow-up visit. Levels of immune activation and EM CD4 T cells declined within six months of HAART but the percentages of EM CD4 T cells and effector CD8 T cells remained elevated through 30 months of HAART. IL-7Rα-expressing CD8 T cells increased with HAART, suggesting expansion of memory capacity.
HAART significantly reduced levels of immune activation and EM CD4 T cells, and promoted reconstitution of naïve T cells and IL-7Rα-expressing CD8 T cells. However, persistently high levels of EM CD4 T cells in HIV-infected children may reflect chronic perturbations in T cell subset composition