title: Evaluation of circulating osteopontin levels in an unselected cohort of patients with multiple sclerosis: relevance for biomarker development.
abstract: BACKGROUND
  Osteopontin (OPN) is a pleiotropic protein with important roles in inflammation and immunity that has been suggested as a candidate biomarker for disease activity in multiple sclerosis (MS).
  
  
  OBJECTIVE
  We evaluated plasma levels of OPN in an unselected cohort of MS patients, to determine its potential as a biomarker for disease subtype and/or disease activity in a regular clinical setting.
  
  
  METHODS
  We analyzed OPN plasma levels in 492 consecutive MS patients, using a commercial enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  OPN levels were higher in relapsing-remitting and secondary progressive MS, compared to healthy controls. Treatment with natalizumab or glatiramer acetate was associated with lower OPN levels. There was no significant association between the OPN levels and disease activity, as measured by clinical or radiological criteria. One-third of patients with high OPN levels had concurrent disorders that may also be associated with increased OPN expression, and which may mask a modest effect of MS disease activity on OPN levels.
  
  
  CONCLUSIONS
  Our data do not support a role for circulating OPN levels as a biomarker for disease activity in a heterogeneous clinical setting, but does not rule out a potential role in the cerebrospinal fluid, in a controlled setting such as a clinical trial, or in concert with other biomarkers.
authors.affiliation: Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Pia
authors.initials: P
authors.lastname: Kivisäkk
authors.forename: Brian C
authors.initials: BC
authors.lastname: Healy
authors.forename: Katiana
authors.initials: K
authors.lastname: Francois
authors.forename: Roopali
authors.initials: R
authors.lastname: Gandhi
authors.forename: Taha
authors.initials: T
authors.lastname: Gholipour
authors.forename: Svetlana
authors.initials: S
authors.lastname: Egorova
authors.forename: Velina
authors.initials: V
authors.lastname: Sevdalinova
authors.forename: Francisco
authors.initials: F
authors.lastname: Quintana
authors.forename: Tanuja
authors.initials: T
authors.lastname: Chitnis
authors.forename: Howard L
authors.initials: HL
authors.lastname: Weiner
authors.forename: Samia J
authors.initials: SJ
authors.lastname: Khoury
mesh_terms: D000328:Adult; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D001921:Brain / Q000473:pathology; D015331:Cohort Studies; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D000068717:Glatiramer Acetate; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000097:blood* / Q000188:drug therapy / Q000473:pathology; D000069442:Natalizumab; D053495:Osteopontin / Q000097:blood*; D010455:Peptides / Q000627:therapeutic use
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D015415:Biomarkers; D007166:Immunosuppressive Agents; D000069442:Natalizumab; D010455:Peptides; D053495:Osteopontin; D000068717:Glatiramer Acetate
keywords: Biomarker; ELISA; disease; multiple sclerosis; osteopontin; plasma