RT Journal Article SR Electronic T1 Phagocyte-specific S100A8/A9 Protein Levels During Disease Exacerbations and Infections in Systemic Lupus Erythematosus JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 2190 OP 2194 DO 10.3899/jrheum.081302 VO 36 IS 10 A1 MUHAMMAD S. SOYFOO A1 JOHANNES ROTH A1 THOMAS VOGL A1 ROLAND POCHET A1 GUY DECAUX YR 2009 UL http://www.jrheum.org/content/36/10/2190.abstract AB Objective: S100A8 and S100A9 are calcium binding proteins of the S100 family highly expressed in neutrophils and monocytes. S100 proteins are novel ligands of TLR4 important in modulating inflammation. High levels of S100A8/A9 found in human inflammatory diseases are a marker of disease activity in rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA). We determined levels of S100A8/A9 in sera of patients with systemic lupus erythematosus (SLE) and analyzed their relation to clinical variables of disease activity. Methods. A group of 93 patients with SLE were studied over a period of 3 years, and 143 serum samples were analyzed. S100A8/A9 serum concentrations were determined by a sandwich ELISA. Sera from 10 primary Sjögren’s syndrome (pSS) patients and 50 healthy volunteers were used as controls. Correlations to SLEDAI, ANA, anti-dsDNA, WBC, CH50, C4, and CRP were made. In addition, infections were recorded in all SLE patients. Results. Serum levels of S100A8/A9 were significantly (p = 0.04) higher in SLE patients (1412 ± 664 ng/ml) versus healthy controls (339 ± 35 ng/ml) and pSS patients (400 ± 85 ng/ml). The only significant correlation (r = 0.219; p = 0.015) was found was between S100A8/A9 and SLEDAI. Further, SLE patients with concomitant infections had higher serum levels of S100A8/A9 (39300 ± 13375 ng/ml) than those without infections (1150 ± 422 ng/ml). Conclusion. Serum levels of S100A8/A9 are significantly raised in SLE versus pSS patients and healthy controls and can be correlated to a disease activity index. S100A8/A9 is a more relevant marker of infection in SLE patients.