Immunosenescence is the gradual deterioration of the immune system, brought on by natural age advancement. A 2020 review concluded that the adaptive immune system is affected more than the innate immune system.[1] Immunosenescence involves both the host's capacity to respond to infections and the development of long-term immune memory. Age-associated immune deficiency is found in both long- and short-lived species as a function of their age relative to life expectancy rather than elapsed time.[2]
It has been studied in animal models including mice, marsupials and monkeys.[3][4][5] Immunosenescence is a contributory factor to the increased frequency of morbidity and mortality among the elderly. Along with anergy and T-cell exhaustion, immunosenescence belongs among the major immune system dysfunctional states. However, while T-cell anergy is a reversible condition, as of 2020 no techniques for immunosenescence reversal had been developed.[6][7]
Immunosenescence is not a random deteriorative phenomenon, rather it appears to inversely recapitulate an evolutionary pattern. Most of the parameters affected by immunosenescence appear to be under genetic control.[8] Immunosenescence can be envisaged as the result of the continuous challenge of the unavoidable exposure to a variety of antigens such as viruses and bacteria.[9]
^Ginaldi L, Loreto MF, Corsi MP, Modesti M, De Martinis M (August 2001). "Immunosenescence and infectious diseases". Microbes and Infection. 3 (10): 851–857. doi:10.1016/S1286-4579(01)01443-5. PMID11580980.
^Franceschi C, Valensin S, Fagnoni F, Barbi C, Bonafè M (December 1999). "Biomarkers of immunosenescence within an evolutionary perspective: the challenge of heterogeneity and the role of antigenic load". Experimental Gerontology. 34 (8): 911–921. doi:10.1016/S0531-5565(99)00068-6. PMID10673145. S2CID32614875.
^Franceschi C, Bonafè M, Valensin S (February 2000). "Human immunosenescence: the prevailing of innate immunity, the failing of clonotypic immunity, and the filling of immunological space". Vaccine. 18 (16): 1717–1720. doi:10.1016/S0264-410X(99)00513-7. PMID10689155.