Aging of immune system

In old people, many alterations of innate and adaptive immunity have been described and viewed as deleterious, hence the term immunosenescence. Immunosenescence is a complex process involving multiple reorganizational and developmentally regulated changes, rather than a simple unidirectional decline of the whole function. Whereas innate immunity is relatively well preserved in older people, adaptive immunity is more susceptible due both to the functional decline associated with the passage of time and to antigen burden to which an individual has been exposed during lifetime. Although it is conceivable that global immune changes may lead to various diseases, it is also obvious that these changes may be needed for extended survival/longevity. This chapter summarizes recent data on the dynamic reassessment of immune changes with aging.