In the setting of rheumatoid arthritis, pro-inflammatory cytokine levels are elevated, which includes IFN-γ, TNF-α, IL-6, IL-1, GM-CSF [11] and chemokines such as chemokine C-C motif ligand 2 (CCL2) [12] and CCL13 [13]. The gene discussed is CCL2; the disease is rheumatoid arthritis.