Treatment-resistant expansion of CD8+CD28-cells in pediatric HIV infection

Abstract

There is a disease stage-dependent loss of CD28 expression on T cells in HIV-infected children. In this study, T cell recovery, in particular CD28 expression on T cells, was analyzed after initiation of highly active antiretroviral therapy in a group of eight mostly treatment-naive HIV- infected children. Plasma HIV-RNA levels were recorded, and numbers of CD4, CD8, CD4+CD28+, and CD8+CD28+ cells were determined by two-color flow cytometry. Values after 12 mo of therapy were compared with age-matched, seronegative control subjects. CD4 recovery to subnormal values was observed in all children. CD8 +CD28 + cells recovered and were within the normal range after 12 mo of therapy (patients, 703 ± 250 cells/μL; controls, 789 ± 269 cells/μL), whereas CD8+CD28- cells (546 ± 269 cells/μL) remained significantly expanded compared with age-matched controls (140 ± 35 cells/μL). Expansions of CD8+CD28- cells persisted even in cases with long- term suppression of viral replication. Highly active antiretroviral therapy in HIV-infected children induces substantial but incomplete T cell recovery.