title: Discovery and confirmation of a protein biomarker panel with potential to predict response to biological therapy in psoriatic arthritis.
abstract: OBJECTIVE
  Biological therapies, which include antitumour necrosis factor-α and T-cell inhibitors, are potentially effective treatments for psoriatic arthritis (PsA) but are costly and may induce a number of side effects. Response to treatment in PsA is variable and difficult to predict. Here, we sought to identify a panel of protein biomarkers that could be used to predict which patients diagnosed with PsA will respond to biologic treatment.
  
  
  METHODS
  An integrated discovery to targeted proteomics approach was used to investigate the protein profiles of good and non-responders to biological treatments in patients with PsA. Reverse-phase liquid chromatography coupled to tandem mass spectrometry was used to generate protein profiles of synovial tissue obtained at baseline from 10 patients with PsA. Targeted proteomics using multiple reaction monitoring (MRM) was used to confirm and prevalidate a potential protein biomarker panel in 18 and 7 PsA patient samples, respectively.
  
  
  RESULTS
  A panel of 107 proteins was selected, and targeted mass spectrometry MRM assays were successfully developed for 57 of the proteins. The 57 proteins include S100-A8, S100-A10, Ig kappa chain C fibrinogen-α and γ, haptoglobin, annexin A1 and A2, collagen alpha-2, vitronectin, and alpha-1 acid glycoprotein. The proteins were measured simultaneously and confirmed to be predictive of response to treatment with an area under the curve of 0.76. In a blinded study using a separate cohort of patients, the panel was able to predict response to treatment.
  
  
  CONCLUSIONS
  The approach reported here and the initial data provide evidence that a multiplexed protein assay of a panel of biomarkers that predict response to treatment could be developed.
  
  
  BACKGROUND
  ISRCTN23328456.
authors.affiliation: UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland.
authors.forename: Opeyemi S
authors.initials: OS
authors.lastname: Ademowo
authors.affiliation: UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland UCD School of Mathematical Sciences, University College Dublin, Dublin, Ireland.
authors.forename: Belinda
authors.initials: B
authors.lastname: Hernandez
authors.affiliation: UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland Department of Rheumatology, St. Vincent's University Hospital Dublin, Dublin, Ireland.
authors.forename: Emily
authors.initials: E
authors.lastname: Collins
authors.affiliation: UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland.
authors.forename: Cathy
authors.initials: C
authors.lastname: Rooney
authors.affiliation: UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland Department of Rheumatology, St. Vincent's University Hospital Dublin, Dublin, Ireland.
authors.forename: Ursula
authors.initials: U
authors.lastname: Fearon
authors.affiliation: Department of Clinical Immunology/Rheumatology, Academic Medical Centre/University of Amsterdam, Amsterdam, Netherlands.
authors.forename: Arno W
authors.initials: AW
authors.lastname: van Kuijk
authors.affiliation: Department of Clinical Immunology/Rheumatology, Academic Medical Centre/University of Amsterdam, Amsterdam, Netherlands.
authors.forename: Paul-P
authors.initials: PP
authors.lastname: Tak
authors.affiliation: Department of Clinical Immunology/Rheumatology, Academic Medical Centre/University of Amsterdam, Amsterdam, Netherlands.
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Gerlag
authors.affiliation: UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland Department of Rheumatology, St. Vincent's University Hospital Dublin, Dublin, Ireland.
authors.forename: Oliver
authors.initials: O
authors.lastname: FitzGerald
authors.affiliation: UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland.
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Pennington
mesh_terms: D000068879:Adalimumab / Q000627:therapeutic use*; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D015535:Arthritis, Psoriatic / Q000175:diagnosis / Q000188:drug therapy*; D015415:Biomarkers / Q000378:metabolism*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D011506:Proteins / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D013583:Synovial Membrane / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D015415:Biomarkers; D011506:Proteins; D000068879:Adalimumab
keywords: Anti-TNF; Cytokines; DAS 28; Treatment