CD4 and myeloid sarcoma: In the common experimental model of MS, experimental autoimmune encephalomyelitis (EAE)–infiltrating CD4+ T cells are re-activated in the CNS by APCs, including CD11c+ DCs, with the resulting inflammatory response leading to monocyte recruitment into the CNS, and naïve CD4+ T-cell activation through epitope spreading that further fuels the inflammation (2, 3, 4, 5).