IL2RA and atherosclerosis: However, in the context of atherosclerosis, Treg cells become unstable and may switch sides from immunosuppressive to immunostimulatory T cells during Treg/TH17 cell conversion: (1) they acquire additional transcription factors in addition to the hallmark transcription factor FoxP3 (plasticity); and (2) they lose FoxP3 and CD25, the high-affinity IL-2 receptor (Treg cell instability) generating cells termed exTreg cells32,44.