In agreement with previous observations [62,63] the study found that lack of PD-1 expression in Treg cells increased their suppressive function and demonstrated the in vivo significance of this effect by the improved outcomes in mouse models of autoimmunity, such as experimental autoimmune encephalomyelitis (EAE) and nonobese diabetes (NOD) selectively lacking PD-1 in Treg cells [65]. The gene discussed is PDCD1; the disease is experimental autoimmune encephalomyelitis.