FOXP3 and systemic lupus erythematosus: To further investigate the origin of the expanded CD45RA− FOXP3+ Tregs in SLE patients we further stratified the distribution of both CD25low (Figure 3A) and CD25hi (Figure 3B) Treg populations according to the expression of HELIOS, a key transcription factor required to maintain the Treg transcriptional programme and suppressive function (33).