title: Correlation of fractalkine concentrations in serum and synovial fluid with the radiographic severity of knee osteoarthritis.
abstract: BACKGROUND
  Fractalkine has been detected in synovial fluid (SF) from osteoarthritis (OA) patients. This study aims to examine the relation of fractalkine concentrations in serum and SF with the radiographic severity of OA.
  
  
  METHODS
  Fractalkine concentrations of serum and SF were measured using an enzyme-linked immunosorbent assay method in 223 patients with knee OA and 165 healthy controls. The progression of OA was classified according to the Kellgren-Lawrence grading system.
  
  
  RESULTS
  Elevated concentrations of fractalkine in serum were found in knee OA patients compared with healthy controls [all results median (interquartile range) 226.25 (183.19-259.91) vs. 127.42 (99.54-154.98) pg/mL, P < 0.001]. The case group included 71 knee OA patients with grade 2, 98 with grade 3, and 54 with grade 4. Knee OA patients with KL grade 4 had significantly higher fractalkine concentrations in serum and SF compared with those with KL grade 2 and 3 [serum: 247.68 (215.05-278.64) vs. 212.45 (169.19-247.96) pg/mL, P < 0.001, and 247.68 (215.05-278.64) vs. 222.00 (179.80-254.98) pg/mL, P = 0.005, respectively; SF: 94.95 (76.46-106.68) vs. 74.31 (63.64-84.79) pg/mL, P < 0.001, and 94.95 (76.46-106.68) vs. 80.34 (68.84-96.39) pg/mL, P = 0.001, respectively]. Knee OA patients with KL grade 3 showed significantly elevated concentrations of fractalkine in SF compared with those with KL grade 2 [80.34 (68.84-96.39) vs. 74.31 (63.64-84.79) pg/mL, P = 0.004]. Fractalkine concentrations in serum and SF of knee OA patients were both significantly associated with the disease severity evaluated by KL grading criteria (r = 0.261, P < 0.001 and r = 0.366, P < 0.001, respectively).
  
  
  CONCLUSIONS
  The fractalkine concentrations in serum and SF may serve as an effective biomarker for the severity of OA.
authors.affiliation: Department of Traditional Chinese Medicine, Southern Medical University, Guangzhou, People's Republic of China.
authors.forename: Yucong
authors.initials: Y
authors.lastname: Zou
authors.forename: Yikai
authors.initials: Y
authors.lastname: Li
authors.forename: Lu
authors.initials: L
authors.lastname: Lu
authors.forename: You
authors.initials: Y
authors.lastname: Lin
authors.forename: Weiming
authors.initials: W
authors.lastname: Liang
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Su
authors.forename: Xusheng
authors.initials: X
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
authors.forename: Jianming
authors.initials: J
authors.lastname: Wang
authors.forename: Chengfu
authors.initials: C
authors.lastname: Yu
authors.forename: Liwei
authors.initials: L
authors.lastname: Huo
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Ye
mesh_terms: D016022:Case-Control Studies; D054428:Chemokine CX3CL1 / Q000032:analysis / Q000097:blood*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000097:blood* / Q000000981:diagnostic imaging*; D011859:Radiography; D013582:Synovial Fluid / Q000737:chemistry*
chemical_list: D054428:Chemokine CX3CL1
keywords: Fractalkine; osteoarthritis; serum; severity; synovial fluid