Impact of CMV and EBV seropositivity on CD8 T lymphocytes in an old population from West-Sicily.

Herpes viruses (particularly CMV and to some extent EBV) might play a role in accelerating the deterioration of immune functions with age. Indeed, it has been demonstrated that chronic infection with CMV causes an expansion of specific CD8 T lymphocytes and that this is related to a shrinkage of the T cell repertoire in very elderly people, predicting mortality. We have analysed CD8 T cells in young and old healthy Sicilians who were both CMV- and EBV-seropositive. Our data confirm expansions of T cells specific for the HLA-A2-restricted pp65 (495-503) CMV epitope up to nearly 14% of total peripheral CD8 cells in certain elderly individuals (range 0-14%). However, the mean percentage of CMV-specific cells in the elderly was not greater than the young (range 0.2-3%). The CMV-specific CD8 cells in the elderly were predominantly CD45RA+, but in the young they were mostly CD45RO+. Our findings are somewhat different from published reports from Northern European populations, both in terms of mean numbers and surface phenotypes. These findings may reflect disparate hygienic and nutritional conditions 70-90 yr ago, which were very different in Northern and Southern Europe at that time, as well as a different genetic background.