The infiltrated immune cells and synovial fibroblasts secrete various cytokines, like TNF-α, IL-1β, and IL-6, metalloproteinases (MMPs), and chemokines, such as MCP-1, MIP-1, and RANTES, in the inflamed joint tissues [10] and eventually lead to arthritis including inflammation and bone erosion. The gene discussed is CCL2; the disease is arthritic joint disease.