RESEARCH - Synovial fluid proteins discriminate RA from other inflammatory joint diseases

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Rheumatology Advance Access published online on January 25, 2010

Rheumatology, doi:10.1093/rheumatology/kep452

Synovial fluid proteomic fingerprint: S100A8, S100A9 and S100A12

proteins discriminate rheumatoid arthritis from other inflammatory

joint diseases

Athan Baillet1,2,*, Trocmé1,3,*, Sylvie Berthier1, Marie

Arlotto4, t Grange1,2, Jérôme Chenau5, Sébastien Quétant1,

Michel Sève5, François Berger4, Juvin2, Françoise Morel1 and

Philippe Gaudin1,2

1GREPI CNRS UMR 5525, Grenoble University, 2Clinic of Rheumatology,

CHU Hôpital Sud, 3Laboratory of Enzymology, BEP, CHU Hôpital

Michallon, 4Grenoble Institut Neurosciences, INSERM U836 and 5Biology

Innovation Center, CHU Hôpital Michallon, Grenoble, France.

Abstract

Objective. We investigated SF and serum proteomic fingerprints of

patients suffering from RA, OA and other miscellaneous inflammatory

arthritides (MIAs) in order to identify RA-specific biomarkers.

Methods. SF profiles of 65 patients and serum profiles of 31 patients

were studied by surface-enhanced laser desorption and

ionization–time-of-flight-mass spectrometry technology. The most

discriminating RA biomarkers were identified by matrix-assisted laser

desorption ionization–time of flight and their overexpression was

confirmed by western blotting and ELISA.

Results. Three biomarkers of 10 839, 10 445 and 13 338 Da,

characterized as S100A8, S100A12 and S100A9 proteins, were the most

up-regulated proteins in RA SF. Their expression was about 10-fold

higher in RA SF vs OA SF. S100A8 exhibited a sensitivity of 82% and a

specificity of 69% in discriminating RA from other MIAs, whereas

S100A12 displayed a sensitivity of 79% and a specificity of 64%. Three

peptides of 3351, 3423 and 3465 Da, corresponding to the -defensins-1,

-2 and -3, were also shown to differentiate RA from other MIAs with

weaker sensitivity and specificity. Levels of S100A12, S100A8 and

S100A9 were statistically correlated with the neutrophil count in MIA

SF but not in the SF of RA patients. S100A8, S100A9, S100A12 and

-defensin expression in serum was not different in the three

populations.

Conclusion. The most enhanced proteins in RA SF, the S100A8, S100A9

and S00A12 proteins, distinguished RA from MIA with high accuracy.

Possible implication of resident cells in this increase may play a

role in RA physiopathology.

http://rheumatology.oxfordjournals.org/cgi/content/abstract/kep452v1?papetoc

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