title: Serum interleukin-15 levels are associated with severity of pain in patients with knee osteoarthritis.
abstract: BACKGROUND
  Inflammation plays a crucial role in the development and progression of osteoarthritis (OA). Interleukin-15 (IL-15) is a well-known proinflammatory cytokine.
  
  
  OBJECTIVE
  We aimed at evaluating the relationship between serum IL-15 levels and the severity of pain as well as radiographic progression in patients with knee OA.
  
  
  METHODS
  Two hundred and twenty-six OA patients and 106 controls were enrolled in this study. The symptomatic/radiological severity of OA was assessed by the Western Ontario McMaster University Osteoarthritis Index- (WOMAC-)pain scores/Kellgren-Lawrence (KL) grading system. Serum IL-15 levels were measured by enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  Serum IL-15 levels were significantly higher in OA patients compared with controls. Serum IL-15 levels were independently and positively correlated with WOMAC-pain scores but not KL grades in OA patients.
  
  
  CONCLUSIONS
  We demonstrated that increased serum IL-15 levels were independently correlated with self-reported greater pain in knee OA patients. These results suggest that IL-15 might play a crucial role in the pathogenesis of OA related pain and therapeutic interventions by blocking IL-15 signaling pathways to delay the degenerative process of OA related pain which warrants further investigations.
authors.affiliation: Department of Hand-Foot Surgery, Weifang People's Hospital, Weifang 261041, Shandong, China.
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Sun
authors.forename: Liang-Zhi
authors.initials: LZ
authors.lastname: Sun
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Bao-hui
authors.initials: BH
authors.lastname: Su
authors.forename: Lin
authors.initials: L
authors.lastname: Shi
mesh_terms: D059787:Acute Pain / Q000097:blood* / Q000175:diagnosis; D000368:Aged; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D019409:Interleukin-15 / Q000097:blood*; D007717:Knee / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000097:blood* / Q000000981:diagnostic imaging; D011859:Radiography
chemical_list: D015415:Biomarkers; C569274:IL15 protein, human; D019409:Interleukin-15