Thymic Hormones and Their Role in Aging. The increase in the average life span of humans during the last century has been
accompanied by a parallel increase in a number of diseases associated with aging,
including cancer, and certain infectious and autoimmune diseases. The decline of
immunocompetence with aging has been correlated with the increased incidence of
these diseases and extensive reviews describing the changes in the
immune system during the aging process has recently been published.
Although the decline of the immune system is accompanied by alterations in all its
compartments, the most affected appears to be the T-cell compartment. Decline in T cell mitogen-induced proliferation, allogeneic mixed leukocyte
reaction (MLR), cytotoxic T lymphocyte responses (CTE), helper T-cell activity,
IL2 production, IL2 receptor expression, calcium uptake, PNP activity (PNPpurine
nucleoside phosphorylase), adenylate cyclase activity, etc have been
observed in T-cells from aging individuals and animals. These changes
lead to an increased susceptibility to infections, decrease resistance to tumor
growth, and an increased incidence of autoimmune diseases, probably secondary to
an immunologic imbalar~ce resulting in an increased response towards self antigens, characterized by a rise in the frequency of autoantibodies observed in aged
individuals.
Dominari A, Hathaway Iii D, Pandav K, Matos W, Biswas S, Reddy G, Thevuthasan S, Khan MA, Mathew A, Makkar SS, Zaidi M, Fahem MMM, Beas R, Castaneda V, Paul T, Halpern J, Baralt D. Thymosin alpha 1: A comprehensive review of the literature. World J Virol. 2020 Dec 15;9(5):67-78. doi: 10.5501/wjv.v9.i5.67. PMID: 33362999; PMCID: PMC7747025.