Leukocytes expressing a variety of inflammatory chemokine receptors, most consistently CCR1, CCR2, and CCR5, have been identified in diverse inflammatory tissues and fluids, including synovial fluid from rheumatoid arthritis patients [15], joints of arthritic mice [16], MS brain lesions [17-19] and in neurological disease models including EAE [20,11,23]. Here, CCR1 is linked to myeloid sarcoma.