UC Irvine

There is evidence of declining effectiveness of the immune system with aging. This must reflect a diminution of immune surveillance mechanisms, and gradually leads to the emergence of several harmful tendencies. The ability of the aged to mount an effective defense against micro-organisms and to respond well to vaccination are both impaired. These account for the increased susceptibility of the aged to bacterial and viral disease. Such diminished immune function with aging takes place despite increasing levels of inflammatory activity. The ensuing-elevation of inflammation with no readily recognizable antigenic trigger- leads to compromised tissue function. The increased presence of irrelevant inflammatory activity can result in elevation of oxidative stress and these events together can proceed to adversely effects including organ damage. Additionally, failure of the immune system in the elderly is also reflected by a growing incidence of autoimmune disease. It seems that the defective immune system of age is not just increasingly quiescent but progresses to a different form of action that, while being ineffective in performing its classical role, is expressed in a new faulty configuration leading to harmful rather than favorable outcomes. This article describes some possible mechanisms underlying such a transition. Finding means of impeding of this shift is also discussed since this could alleviate of the diseases associated with senescence.