The increase of IFN-gamma production through aging correlates with the expanded CD8(+high)CD28(-)CD57(+) subpopulation

The use of flow cytometry to detect intracellular cytokines at the single c ell level has the potential to quantify cytokine production together with t he possibility of phenotypic identification of the cell population concerne d. The unbalanced presence of intracellular cytokines produced by T cells h as been recognized in some pathological conditions. To better address this issue, we studied the production of IFN-gamma and IL-4 in CD4(+) and CD8(+h igh) T cells in healthy donors of a broad range of age (17-62 years). Given that an increase of IFN-gamma and IL-4 with aging had been reported by som e authors in healthy controls, we have performed a multivariate analysis to assess the intrinsic role of aging or of other external factors, such as c hronic antigenic exposures (i.e., viruses), over the cytokine production of phenotypically characterized T cells. In this respect we show that, mainly in CD8(+high) T cells, the production of IFN-gamma is directly correlated with age. Besides, the cytokine production correlates with the CD8(+high)CD 28(-)CD57(+) T-cell population, which we have recently reported elevated in aged individuals. Perhaps this T-cell subpopulation plays a regulatory rol e as a Tc1 response in aging individuals. (C) 2000 Academic Press.