Figure 1.

Schematic landscape of Treg in the elderly. During human and mouse aging, there is a decreased efflux of recent thymic emigrants (RTE) to the periphery, a reduction of naïve Treg and an accumulation of antigen experienced memory Treg. As a consequence, TCR-restricted Treg accumulate and the pool of memory T cells is skewed towards memory Treg over effector/memory T cells. This imbalance on T cell homeostasis is related to the development of different diseases. In old age, an increase in Treg function may lead to the progression of tumors, chronic infections or tissue degeneration, whereas an impaired Treg function may cause autoimmunity and/or chronic inflammation.