The great migratory potential of peripheral CD20+ T cells from RR-MS patients was substantiated by the observation that this population was enriched in the CSF, where it showed a higher expression of migration molecules (such as CCR2 and CCR5 on both CD4+ and CD8+; MCAM-1 and CCR6 on CD4+ only) compared to CD20− T cells [13]. The gene discussed is MS4A1; the disease is myeloid sarcoma.