title: Highly sensitive ELISA for determining serum keratan sulphate levels in the diagnosis of OA.
abstract: OBJECTIVE
  There have been a large number of reports on alterations in the serum level of keratan sulphate (KS), a potential marker of articular cartilage degeneration in patients with arthropathy. Such studies have commonly employed ELISA using the anti-KS monoclonal antibody 1/20/5D4 (5D4-ELISA) to determine KS levels. Recently, a highly sensitive KS ELISA (HS-ELISA) kit has been developed, allowing determination of serum KS levels even in small animals, which were formerly undetectable with 5D4-ELISA. However, the effectiveness of this kit in humans has not been demonstrated. The objective of this study was to assess the usefulness of the HS-ELISA for the analysis of human serum samples.
  
  
  METHODS
  Serum samples were collected from 28 patients with knee OA and 23 healthy volunteers. KS was determined by 5D4-ELISA and HS-ELISA, and measurements were compared with those obtained by HPLC. KS levels in serum samples with protease pretreatment were also determined by HS-ELISA.
  
  
  RESULTS
  KS levels determined by HS-ELISA exhibited a better correlation with those determined by HPLC, and a higher diagnostic sensitivity for OA compared with 5D4-ELISA. Protease pretreatment of serum further improved the correlation between the values obtained by HS-ELISA and HPLC, as well as the diagnostic sensitivity of HS-ELISA for OA.
  
  
  CONCLUSIONS
  HS-ELISA proved useful for determining KS level in serum and the diagnosis of OA. Pretreatment of serum samples with a protease further improved the performance of HS-ELISA.
authors.affiliation: Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan. wakitani@med.osaka-cu.ac.jp
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Wakitani
authors.forename: Takahiro
authors.initials: T
authors.lastname: Okabe
authors.forename: Amu
authors.initials: A
authors.lastname: Kawaguchi
authors.forename: Masashi
authors.initials: M
authors.lastname: Nawata
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Hashimoto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D007632:Keratan Sulfate / Q000097:blood*; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D015415:Biomarkers; D007632:Keratan Sulfate