Chemokine (C-X-C motif) receptor 3 (CXCR3) and its ligands (MIG, IP-10) play an important role in multiple sclerosis (MS). The CXCR3 receptor is expressed on the majority of T cells in the cerebrospinal fluid (CSF) of patients with MS, suggesting that the CXCR3 receptor may mediate the trafficking of T cells into the central nervous system. IP-10, and MIG were found to be elevated in the CSF of patients with MS during relapse. These chemokines were also detected in actively demyelinating lesions, and upregulation of CXCR3 expression on peripheral blood CD4+ lymphocytes was associated with MS relapses.Treatment with Interferon (IFN)-β-1a or IFN-β-1b was associated with increased IP-10. Natalizumab that exerts impressive therapeutic effects in patients with MS induces a marked decline of Th1 chemokines (MIG, IP-10, I-TAC) in CSF.