.....The effect of aging on Tregs, and the possible contribution of age-related changes of the Treg pool to the pathophysiology of diseases in the elderly are still poorly understood. Treg homeostasis depends on an intact thymic function and current data suggest that conversion of non-regulatory T-cells into Tregs as well as peripheral expansion of existing Tregs compensates for thymic involution after puberty to maintain constant Treg numbers. In the conventional T-cell subset, peripheral proliferation of T-cells is associated with replicative senescence leading to phenotypical and functional changes. For Tregs, different developmental stages were also described; however, replicative senescence of Tregs has not been observed yet. "
In this review we summarize current data about the effects of aging on T
regs
 and highlight the possible mechanisms leading to senescence of T
regs
."