Analysis of T and NK cell subsets in Sicilian population from young to supercentenarian: the role of age and gender.

Ageing dramatically affects number and function of both innate and adaptive arms of immune system, particularly T cell subsets, contributing to reduced vaccination efficacy, decreased resistance to infections and increased prevalence of cancer in the older people. In the present paper, we analysed the age-related changes in the absolute number of lymphocytes in 214 Sicilian subjects, and in the percentages of T and NK cells in a sub-cohort of donors. We compared these results with the immunophenotype of the oldest living Italian supercentenarian (111 years old). The results were also sorted by gender. The correlation between number/percentage of cells and age in all individuals and, separately, in males and females, was examined using a simple linear regression analysis. We did not record the increase in the rate of inversion of the CD4/CD8 ratio frequently reported as associated with ageing in literature. Our observation was the direct consequence of a flat average trend of CD4+ and CD8+ T cell percentages in ageing donors, even when gender differences were included. Our results also suggest that CD4+ and CD8+ subsets are not affected equally by age comparing females with males, and we speculated that gender may affect the response to CMV infection. The supercentenarian showed a unique immunophenotypic signature as regards the relative percentages of her T cell subsets, with CD4+ and CD8+ T cell percentages and CD4+ naive T cell values in line with those recorded for the octogenarian subjects. This suggests that the supercentenarian has a naive "younger" T cell profile comparable to that of a >80 year old female.