title: The role of sex steroids and gonadectomy in the control of thymic involution.
abstract: A major underlying cause for aging of the immune system is the structural and functional atrophy of the thymus, and associated decline in T cell genesis. This loss of naïve T cells reduces adaptive immunity to new stimuli and precipitates a peripheral bias to memory cells against prior antigens. Whilst multiple mechanisms may contribute to this process, the temporal alliance of thymic decline with puberty has implicated a causative role for sex steroids. Accordingly ablation of sex steroids induces profound thymic rejuvenation. Although the thymus retains some, albeit highly limited, function in healthy adults, this is insufficient for resurrecting the T cell pool following cytoablative treatments such as chemo- and radiation-therapy and AIDS. Increased risk of opportunistic infections and cancer relapse or appearance, are a direct consequence. Temporary sex steroid ablation may thus provide a clinically effective means to regenerate the thymus and immune system in immunodeficiency states.
authors.affiliation: Monash Immunology and Stem Cell Laboratories (MISCL), Level 3, Building-75, Monash University, Wellington Road, Clayton, Melbourne 3800, Australia.
authors.forename: Melanie
authors.initials: M
authors.lastname: Hince
authors.forename: Samy
authors.initials: S
authors.lastname: Sakkal
authors.forename: Katerina
authors.initials: K
authors.lastname: Vlahos
authors.forename: Jarrod
authors.initials: J
authors.lastname: Dudakov
authors.forename: Richard
authors.initials: R
authors.lastname: Boyd
authors.forename: Ann
authors.initials: A
authors.lastname: Chidgey
mesh_terms: D000375:Aging / Q000276:immunology; D000818:Animals; D001284:Atrophy; D004198:Disease Susceptibility; D012739:Gonadal Steroid Hormones / Q000276:immunology*; D006801:Humans; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology* / Q000473:pathology*
chemical_list: D012739:Gonadal Steroid Hormones