XCL1 and arthritic joint disease: In the K/BxN-serum-transfer arthritis model the concentrations of chemokine (C-X-C motif) ligand 1 (CXCL1) also called KC and chemokine (C-X-C motif) ligand 2 (CXCL2) also called macrophage inflammatory protein 2 (MIP-2) significantly increased in the ankle joint homogenates of vehicle-treated arthritic mice (n = 5) on day 4 compared to non-arthritic animals (n = 6).