Inborn errors of regulatory T-cell differentiation and function.

Regulatory T (Treg) cells play an essential role in enforcing peripheral immune tolerance and promoting tissue homeostasis and repair. Our understanding of their pivotal role in immune regulation has critically benefited from the identification of a growing number of inborn errors of immunity known as Tregopathies, which target different pathways governing Treg cell biology. The resulting disorders associated with mutations in gene such as FOXP3, CTLA4, IL2RA, IL2RB, BACH2, IKAROS, STAT3, LRBA, and DEF6 manifest both unique and overlapping phenotypes of immune dysregulation and autoimmunity, highlighting the distinctive roles of individual Treg cell pathways targeted by inborn errors of immunity in immune regulation. We examine the current knowledge of Tregopathies and the immune regulatory networks they affect.