Studies investigating CD4+CD25highFoxp3+ Tregs in MS patients showed functional impairment [20,21,22] linked to reduced Foxp3 expression [20,22] and reduced frequency of Foxp3+ cells [22], whereas other investigators found decreased levels during remission, which were restored to normal levels during the acute phase of the disease [23]. Here, FOXP3 is linked to myeloid sarcoma.