Serum S100A8/9 and S100A12 are alarmin proteins predominantly released at inflammatory sites by activated innate immune effectors including monocytes/macrophages and neutrophils [14, 15]; these proteins reflect the degree of local inflammation (e.g. synovitis) and are considered to be more specific biomarkers than other systemic inflammatory biomarkers such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) in rheumatoid arthritis (RA) [16, 17]. Here, CRP is linked to rheumatoid arthritis.