Role of the immune system in aging and longevity.

The aging process is a universal, intrinsic, progressive accumulation of deleterious changes in cells and tissues that increases morbidity and leads to death. The heterogeneity of the age-related physiological changes is shown by the "biological age", which determines the rate of ageing experienced by each individual and therefore his life expectancy. According to the recent theory of oxidation-inflammation to explain the aging process, the immune system seems to be involved in the chronic oxidative and inflammatory stress conditions of aging. It has been proposed that several age-related changes in immune cell functions, which depend on the redox state of these cells, could be good markers of health, biological age and longevity. In order to identify parameters of the functional and redox situation of immune cells as markers of biological age and predictors of longevity, we have studied those parameters in human healthy centenarians, in extreme long-living mice, as models of successful aging, and in immune cells from murine models of premature immunosenescence. The aim of the present work is to review the results in humans and rodents on those parameters and their relationship with biological age and longevity, as well as to propose several strategies of lifestyle useful to improve the immune function and thus to increase the mean life span.