Expression of CD69 on T-cells from HIV-1-infected children and adolescents increases with increasing viral load

We evaluated the use of a whole-blood assay that measures spontaneous and activation-induced CD69 expression on peripheral blood T-cells in vitro for assessment of T-cell function in HIV-I-infected paediatric patients. Heparinized venous blood from 28 HIV-I positive children and adolescents and 23 healthy controls was incubated for 4 h with or without 5 mu g/ml phytohaemagglutinin (PHA).;Thereafter, analysis of CD69 expression on CD4(+) and CD8(+) T-cells was done by flow cytometry; simultaneously we determined CD4(+) T-cell counts and plasma HIV-1 viral load. Neither spontaneous nor PHA-induced CD69 expression differed significantly between HIV-1 positive patients and healthy controls. However, T-cells from HIV-1 positive patients with plasma HIV-I viral load levels above 70 x 10(3) copies/ml showed a higher spontaneous CD69 expression. than T-cells from patients with lower plasma viral load levels in different stages of the disease. Antiretroviral treatment in four patients reduced spontaneous CD69 expression in CD4(+) T-cells and PHA-induced CD69 expression in CD4(+) and CD8(+) T-cells significantly after 8 weeks of therapy. Conclusion Spontaneous and activation-induced expression of the early (activation) antigen CD69 on;peripheral. blood T-cells does not distinguish HIV-1 positive patients from HIV-1 negative healthy controls and is not correlated with peripheral blood CD4(+) T-cell counts. This test May not be a reliable marker for functional T-cell deficiency during early stages of:HIV disease. Increased spontaneous as-well as PHA-induced CD69 expression on T-cells from HIV-l-infected children and adolescents in vitro may rather reflect HIV-induced pre-activation of T-cells in vivo.