FOXP3 and Autoimmunity: Indeed, loss-of-function mutations of Foxp3 in mice and men, or the ablation of Foxp3+ cells in transgenic mice, all lead to lethal autoimmunity (Brunkow et al., 2001; Gambineri et al., 2003; Kim et al., 2007; Lahl et al., 2007; Sakaguchi et al., 2008).