Human FOXP3+ Regulatory T Cell Heterogeneity and Function in Autoimmunity and Cancer.

Regulatory T (Treg) cells expressing the transcription factor Foxp3 have a critical role in the maintenance of immune homeostasis and prevention of autoimmunity. Recent advances in single cell analyses have revealed a range of Treg cell activation and differentiation states in different human pathologies. Here we review recent progress in the understanding of human Treg cell heterogeneity and function. We discuss these findings within the context of concepts in Treg cell development and function derived from preclinical models and insight from approaches targeting Treg cells in clinical settings. Distinguishing functional Treg cells from other T cells and understanding the context-dependent function(s) of different Treg subsets will be crucial to the development of strategies toward the selective therapeutic manipulation of Treg cells in autoimmunity and cancer.