Fractalkine is upregulated by inflammation cytokines such as TNF-α or IFN-γ, it has been proposed to contribute to inflammatory diseases by promoting the transmigration of CX3CR1-expressing cells to inflamed tissues in Crohn disease [8], rheumatoid arthritis, atherosclerosis [9], systemic lupus erythematosus [10], and most recently PBC [5]. Here, CX3CR1 is linked to rheumatoid arthritis.