The decrease in CCR5 and CXCR3 expression and the concomitant increase in CCR7 expression observed on CD4+CD26high T cells in MS patients treated with IFN-β in the present study are consistent with reduced activation or a transition of cells within this T cell subset from tissue-homing effector cells to the central memory T cell subset. Here, CCR5 is linked to myeloid sarcoma.