As the indicators of disease activity of RA, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), serum matrix metalloproteinase 3 (MMP-3), disease activity score in 28 joints (DAS28) CRP, DAS28ESR, simplified disease activity index (SDAI), and clinical disease activity index (CDAI) have been proposed. This evidence concerns the gene MMP3 and rheumatoid arthritis.