It is currently unknown why such specification of the myeloid cell recruitment and localization exists and how it contributes to arthritis immunopathology, but the finding that lining macrophages are longer-lived than interstitial macrophages (3), and that CCR2-positive cells acquire a tell-tale marker of lining macrophages, VSIG4 (2, 16), during the resolution phase of synovial inflammation, may offer a possible cue. Here, CCR2 is linked to arthritic joint disease.