Features of Peripheral T Cell Remigration into the Thymus

The thymus, the central organ of T lymphopoiesis, is traditionally thought to exclusively export T cells. However, a great deal of studies has shown that mature peripheral T cells can return to the thymus and remain there. It is acknowledged that both CD4⁺ and CD8⁺ activated T cells can remigrate into the healthy adult thymus and accumulate predominantly in the medulla. In contrast, naïve T cells can actively populate the thymus of neonates and aged animals, potentially supporting the medulla's functioning. Still, the fate and functions of peripheral T cell remigrants are not fully understood as of today. This review presents experimental findings on peripheral T cell remigration, analyzes phenotypic and traffic features of remigrants, and considers possible effects of backmigration on thymus function.