Expression of CD69 on T-cell subsets in HIV-1 disease.

CD69 is the earliest activation marker newly synthesized and expressed during T lymphocyte activation. In this study, a whole-blood flow-cytometry-based assay was used to assess expression of the activation antigen CD69 on CD4 and CD8 T lymphocytes, and the co-expression of CD69 and CD28 on T cells. The expression of CD69 was studied in both unstimulated and in phytohaemagglutinin (PHA)- or anti-CD(3)/CD(28)-stimulated, 4-h culture, samples. The production of IL-2, IFN-gamma or both cytokines, in CD69(+) T cells, in response to Staphylococcus enterotoxin B was also tested. Fifty-three HIV-1-infected and 21 healthy volunteers participated in this study. In both PHA- and anti-CD(3)/CD(28)-stimulated cultures the percentage of CD69 on CD3(+)CD4(+) T cells was significantly lower in AIDS (and non-responders to HAART) versus healthy controls and the other HIV-1(+) groups. A decrease of CD69(+)CD28(+) T cells after PHA or MoAbs stimulation is noticed in AIDS. No difference in cytokine production was noticed between healthy volunteers and HIV-1(+) patients. Our results suggest that the expression of CD69 is affected only in the AIDS stage and in the non-responders to HAART patients.