PTEN and experimental autoimmune encephalomyelitis: However, these PTEN-deficient Tregs are unstable, which could spontaneously downregulate CD25 and subsequently loss FOXP3 expression during in vitro culture with IL-2 supplementation and as Pten-ΔTreg mice age, and might be pathogenic as they could not resolve the induced experimental autoimmune encephalomyelitis in Pten-ΔTreg mice (35).