FOXP3 and systemic lupus erythematosus: The phenotypic changes associated with CD25hi FOXP3+HELIOS+ memory Tregs suggest that these cells have expanded in SLE patients in response to an inflammatory, autoimmune reaction; the chronic stimulation could cause CD25 levels on Tregs to decrease due to IL-2RA mRNA down-regulation or to cleavage of the CD25 molecule from the cell surface.