CCL2 and rheumatoid arthritis: Examples are monocyte chemoattractant protein 1 (MCP-1) which is associated to recruitment of monocytes in RA [16] and correlated with the swollen joint count in RA patients [17] and matrix metalloproteinase 3 (MMP3) which is involved in degradation of the extracellular matrix [18] and have been identified as an independent predictor for radiographic progression in SpA and RA [19, 20].