CCR5 and myeloid sarcoma: Rantes/CCL5 and its receptor CCR1, CCR3 and CCR5 have been detected in active demyelinating plaques on immune and microglia cells [71, 72], its expression in serum is higher in RR-MS patients with active lesions and clinical activity [68, 73, 74] and its concentration decreases in CSF after corticosteroid therapy [75].