Furthermore, the neuron- and oligodendrocyte-anchored immunoregulatory “Don’t eat me”-signals, CD200 and CD47, dampen the activity of their receptor/ligand on microglia and macrophages, but in chronic active and inactive MS lesions, CD200 and CD47 expression is reduced, which is accompanied by increased microglial activation, complement expression at the lesion rim, and axonal and oligodendroglial damage [175,176,177,178,179]. Here, CD200 is linked to myeloid sarcoma.