Previous studies aiming to induce antigen-specific immune tolerance as a potential immune therapy approach for MS, have shown important roles for PD-L1 and PD-1, including intravenous (i.v.)administration of high-dose free peptide (52), myelin peptide antigens cross-linked to the surface of syngeneic splenic leukocytes with ethylene carbodiimide (ECDI) (53) or encapsulated in nanoparticles (54), and of mannan-conjugated MOG (31). This evidence concerns the gene PDCD1 and myeloid sarcoma.