A subset of CD4+ forkhead box protein 3 (Foxp3)+Helios+ Treg cells are increased in active SLE and positively correlated with the disease’s activity.201,202 Compared with Foxp3+Helios– Treg cells, Foxp3+Helios+ Treg cells have stronger suppressive potential with limited expression of IL-2 and IFN-γ. Here, IKZF2 is linked to systemic lupus erythematosus.