Two of the currently approved MS drugs, natalizumab (NAT) and fingolimod (FTY), act via selective interference with immune cell trafficking: NAT targets the α4-chain (CD49d) of the α4β1 integrin expressed on immune cells, therefore, directly interfering with adhesion to endothelial cell layers including the BBB (4), leaving peripheral immune cell subset composition mainly unaltered (5). Here, BRD2 is linked to myeloid sarcoma.