CCL2 and myeloid sarcoma: A priori, CCL2 released from astrocyte endfeet may be partly responsible for the loss of BBB properties that accompanies both EAE [16] and MS [17], assisting development of a chemotactic gradient across the microvascular wall to drive the migration of adhered leukocytes past the endothelium, and/or further guiding extravasated leukocytes into the CNS parenchyma [18].