Korean J Intern Med.  2014 Jan;29(1):12-19. 10.3904/kjim.2014.29.1.12.

S100A8/A9 as a biomarker for synovial inflammation and joint damage in patients with rheumatoid arthritis

• Kang KY
• Woo JW
• Park SH

• KMID: 1792006
• DOI: http://doi.org/10.3904/kjim.2014.29.1.12

Abstract

S100A8 and S100A9 are major leukocyte proteins, known as damage-associated molecular patterns, found at high concentrations in the synovial fluid of patients with rheumatoid arthritis (RA). A heterodimeric complex of S100A8/A9 is secreted by activated leukocytes and binds to Toll-like receptor 4, which mediates downstream signaling and promotes inflammation and autoimmunity. Serum and synovial fluid levels of S100A8/A9 are markedly higher in patients with RA than in patients with osteoarthritis or miscellaneous inflammatory arthritis. Serum levels of S100A8/A9 are significantly correlated with clinical and laboratory markers of inflammation, such as C-reactive protein, erythrocyte sedimentation rate, rheumatoid factor, and the Disease Activity Score for 28 joints. Significant correlations have also been found between S100A8/A9 and radiographic and clinical assessments of joint damage, such as hand radiographs and the Rheumatoid Arthritis Articular Damage score. In addition, among known inflammatory markers, S100A8/A9 has the strongest correlation with total sum scores of ultrasonography assessment. Furthermore, baseline levels of S100A8/A9 are independently associated with progression of joint destruction in longitudinal studies and are responsive to change during conventional and biologic treatments. These findings suggest S100A8/A9 to be a valuable diagnostic and prognostic biomarker for RA.

Keyword

S100A8; S100A9; Arthritis, rheumatoid; Biological markers

MeSH Terms

Arthritis, Rheumatoid/*blood/pathology/radiography
Arthrography
Biological Markers/blood
Calgranulin A/*blood
Calgranulin B/*blood
Humans
Joints/pathology
Synovial Fluid/metabolism
Biological Markers
Calgranulin A
Calgranulin B