The release of CXCR2-positive granulocytes in bone marrow at the early stage of cerebral ischemia (4 hours) is related to the rapid systemic up-regulation of CXCL1 (CXCR2 ligand) and granulocyte colony-stimulating factor (key cytokines involved in bone marrow leukocyte mobilization). Here, CXCR2 is linked to brain ischemia.