A fresh look at a neglected regulatory lineage: CD8+Foxp3+ Regulatory T cells.

• CD8+Foxp3+ T cells are the counterpart to the better studies CD4+Foxp3+ Treg population. • CD8+Foxp3+ T cells share a common transcriptional profile and suppressive function with CD4+Foxp3+ Tregs. • CD8+Foxp3+ T cells have been reported to have a role in several disease states. • CD8+Foxp3+ T cells may have a unique function in regulating B cell responses. CD4+Foxp3+ Regulatory T cells (Tregs) are essential for maintaining self-tolerance and are increasingly recognised to have important roles in tissue homeostasis and repair. In the CD8 compartment an analogous Foxp3+ population is present, which shares phenotypic aspects with the more common CD4+Foxp3+Treg population. While oft neglected for their low frequency, there is increasing evidence that these CD8+Foxp3+ cells are bona fide regulatory cells, with both shared and distinct characteristics from their CD4+ analogue. Here we focus on the evidence for a regulatory function of CD8+Foxp3+ cells, and the potential unique role this neglected lineage may play in immune homeostasis and disease prevention. [ABSTRACT FROM AUTHOR]