FOXP3 and myeloid sarcoma: VLA-4 blockade is associated with an increase of the absolute lymphocyte numbers in the peripheral blood of MS patients [2], [3], however, flow cytometrical analysis of Foxp3+ T regulatory cells in patients treated with Natalizumab demonstrated that Treg frequency was not significantly affected by therapy 30 days after Natalizumab application (n = 15, Figure 3a).