CXCR1 and Arthritis: Our findings that CXCR1/2 signalling supports cartilage homeostasis are not at odds with the well-established pathogenic role of ELR+ CXC chemokines in arthritis.7, 8, 39–43 In physiological conditions, a tight regulation of their expression, together with their matrix binding through HSPGs, allows for the restriction of their signalling domain to the avascular chondrocyte pericellular matrix, away from the reach of inflammatory cells.