Modern society has been characterized by a growing proportion of elderly citizens. Coupled with this increase has been a huge increase in the incidence of chronic diseases associated with the elderly. There is growing evidence that the immune system is implicated in virtually all of these age related illnesses, with the inflammatory response being the triggering mechanism that leads to age-related tissue damage. Indeed, the term “inflammaging” has been coined to describe the underlying inflammatory changes common to most age-related diseases. As we get older, the release of inflammatory markers by the body increases in response to the increased antigenic stress which the immune system has to cope with. Inflammation has been linked to almost all the degenerative diseases of aging, including cancer, diabetes, arthritis, heart disease, multiple sclerosis, Parkinson’s disease and Alzheimer’s.

(Medzhitov R, Janeway C Jr: Innate Immunity. N Engl J Med 2000, 343:338-334).

The increased secretion of inflammatory chemicals in aging is due to a number of factors in addition to the higher incidence of antigens. The decreased population in the body of sex steroids, the cumulative effects of smoking, sub-clinical disorders such as arteriosclerosis, asymptomatic bacteruria as well as higher amount of fat tissue due to a less active life-style are all contributory factors. It is also possible that the immune system dysfunctions to cause a constant, low-grade activation of cytokine producing cells or that the cytokine releasing response does not shut down properly after a legitimate stress response. Another possibility is that increased exposure to infectious agents or cumulative damage to tissues could play a role. Whatever the cause, it is clear that vital, healthy adaptive responses to short term infections or injury can be maladaptive as we age. It appears, then, that age related diseases may well be the price we pay for an immune system that protects us in our early years, but that may cause us harm in our twilight years.

(Candore G, Colonna-Romano G, Lio D, Caruso C: Immunological and Immunogenetic markers of successful and unsuccessful ageing.Advances in Cell Aging and Gerontology 2003, 13:29-45).