Serum and synovial fluid concentrations of cold-inducible RNA-binding protein in patients with rheumatoid arthritis.
OBJECTIVE
There is growing evidence that cold-inducible RNA-binding protein (CIRP) promotes inflammatory responses. This study investigated the relationship between CIRP and rheumatoid arthritis (RA).


METHODS
Peripheral blood and synovial fluid were collected from 15 patients with RA and from 16 patients with osteoarthritis (OA). The concentration of CIRP was measured with the sandwich enzyme-linked immunosorbent assay (ELISA).


RESULTS
The concentration of serum CIRP was significantly elevated in the RA patient group (RA patients = 26.39 ± 10.48 pg/mL, OA patients = 17.14 ± 7.24 pg/mL, P = 0.009). Furthermore, the RA patient group had a significantly higher CIRP concentration than that of the OA patient group in synovial fluid (153.56 ± 108.93 pg/mL vs. 23.63 ± 16.18 pg/mL, P < 0.001). The mean synovial fluid concentration of CIRP was significantly higher than that of the serum concentration in the RA patient group (serum concentration = 26.39 ± 10.48 pg/mL, synovial fluid = 153.56 ± 108.93 pg/mL, P < 0.001). Disease Activity Score of 28 joints (DAS28)-ESR (erythrocyte sedimentation rate) and DAS28-CRP (C-reactive protein) were positively correlated with the synovial fluid concentration of CIRP (DAS28-ESR: r = 0.582, P = 0.023; DAS28-CRP: r = 0.541, P = 0.037).


CONCLUSIONS
The serum and synovial concentrations of CIRP in the RA patients were increased compared to the OA patients. Additionally, the synovial concentration of CIRP in RA patients correlated well with disease activity, that is, the DAS28-ESR/CRP. Based on these results, CIRP mediates inflammation and is a potential marker for synovial inflammation.
Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, Korea.
In Seol
IS
Yoo
Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, Korea.
Sun Young
SY
Lee
Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, Korea.
Chan Keol
CK
Park
Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, Korea.
Jeong Chan
JC
Lee
Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, Korea.
Young
Y
Kim
Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, Korea.
Su Jin
SJ
Yoo
Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, Korea.
Seung Cheol
SC
Shim
Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, Korea.
Yoon Seok
YS
Choi
Department of Dermatology, Chungnam National University School of Medicine, Daejeon, Korea.
Young
Y
Lee
Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, Korea.
Seong Wook
SW
Kang
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000175:diagnosis; D015415:Biomarkers / Q000097:blood; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000032:analysis; D004185:Disability Evaluation; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000097:blood / Q000175:diagnosis; D016601:RNA-Binding Proteins / Q000097:blood*; D012720:Severity of Illness Index; D013582:Synovial Fluid / Q000737:chemistry*; D015854:Up-Regulation
D015415:Biomarkers; C491390:CIRBP protein, human; D018836:Inflammation Mediators; D016601:RNA-Binding Proteins; D002097:C-Reactive Protein
DAS28; cold-inducible RNA-binding protein; osteoarthritis; rheumatoid arthritis