In spite of prominent expansion of CD14+CD16+ monocyte in RA patients (Fig. 1B and 2B), the expression of CX3CR1 was decreased moderately on peripheral CD16+ monocytes and more strikingly on synovial CD16+ monocytes from RA patients (Fig. 4B and 4C). Here, CX3CR1 is linked to rheumatoid arthritis.