FOXP3 and Autoimmunity: Using a unique murine model that enables the tracking of murine T-bet-expressing TREG (Foxp3Thy1.1Tbx21tdTomato-T2A-CreERT2R26YFP-fl-stop-fl), Levine and colleagues showed that the conditional deletion of T-bet in Foxp3+ TREG cells does not lead to autoimmunity in adult mice, although it does generate a mild increase in TH1 activity (195), suggesting T-bet has little to no impact on the way TREG preserve tissue function at the steady-state.