CXCR4 and myeloid sarcoma: Recently, however, the function of CXCL12 in the CNS of mice with EAE, and apparently also of MS patients, was shown to be more complex; depending on its interaction with receptors CXCR4 or CXCR7 and on its spatial and temporal expression, CXCL12 may be anti-inflammatory [4], immunomodulatory [6], and may also promote remyelination [7–10].