CX3CR1 and rheumatoid arthritis: CX3CR1, as a receptor for CX3CL1, is a chemokine receptor known to be related to pain, and CX3CR1/L1 signaling is implicated in the pathogenesis of inflammatory diseases such as atherosclerosis, rheumatoid arthritis, and renal fibrosis by supporting monocyte recruitment and exacerbating tissue damage [46, 47].