RORA and myeloid sarcoma: We find that in MS patients a lower fraction of Treg cells expresses the FoxP3-E2 isoform, compared to healthy donors, and this may deprive Treg cells of a further level of immunoregulation, through the inability to inhibit the transcription factors RORα and RORγt and the consequent failure to prevent the development of proinflammatory cells.