Although several homing receptors are known to be differentially expressed by Tregs in lymphoid tissues compared with those found in peripheral tissues, it remains unclear whether these cells traffic between the two locations. In this issue of the JCI, Tomura et al. report steady-state Treg migration from the skin to draining LNs in mice. Furthermore, they report that not only does skin inflammation exacerbate LN-directed Treg homing, it also triggers reverse circulation of Tregs from LNs to skin, whereby these cells contribute to regulation of the immune response. These results now form a new framework for our understanding of Treg homing.
Hironori Matsushima, Akira Takashima