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 …