Local inflammation within OA joint tissues has also been associated with increased levels of inflammatory proteins, such as IL-1β, interleukin 1 receptor antagonist (IL-1Ra), interleukin 6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), Chemokine (C-X-C motif) ligand 9 (CXCL9 or MIG), vascular endothelial growth factor (VEGF) or granulocyte-macrophage-colony-stimulating factor (GM-CSF) in the sera of OA patients with joint effusions, compared with controls [5,6]. The gene discussed is CXCL9; the disease is arthropathy.