title: Identification of a novel autoantigen in inflammatory bowel disease by protein microarray.
abstract: BACKGROUND
  Patients with inflammatory bowel disease (IBD) display immunoreactivity to self-antigens and microbial antigens. We used a protein microarray approach to identify novel autoantigens in IBD.
  
  
  METHODS
  ProtoArray Human Protein Microarray v4.0 containing 8268 human proteins from Invitrogen (La Jolla, CA) was used.
  
  
  RESULTS
  Twenty-five IBD patients and five healthy controls were screened for candidate autoantigens. For 256 antigens, IBD patients had a higher seroreactivity than controls. Twenty antigens were selected for further evaluation in a larger cohort (60 ulcerative colitis [UC] patients, 60 Crohn's disease [CD] patients, 60 healthy controls, and 60 gastrointestinal-diseased controls) by means of a customized protein microarray. Out of these 20 antigens, one antigen, family with sequence similarity 84 member A (FAM84A), was identified as a target antigen in IBD. Antibodies to FAM84A were significantly more prevalent in IBD patients (19%) than in gastrointestinal-diseased controls (1.7%) (P = 0.0008) and healthy controls (5%) (P = 0.01). Anti-FAM84A antibodies were found in 26.6% of UC patients and in 11.7% of CD patients. FAM84A was confirmed as target antigen in IBD by means of Western blotting in a large independent cohort (100 UC patients, 106 CD patients, 102 healthy controls, and 100 gastrointestinal-diseased controls). Antibodies to FAM84A were significantly more prevalent in IBD patients (20%) than in gastrointestinal-diseased controls (5%) (P = 0.0004) and healthy controls (0%) (P < 0.0001). Anti-FAM84A antibodies were found in 18% of UC patients and in 22% of CD patients.
  
  
  CONCLUSIONS
  We identified FAM84A as a novel autoantigen in IBD. (Inflamm Bowel Dis 2011;).
authors.affiliation: Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Vermeulen
authors.forename: Katrijn Op
authors.initials: KO
authors.lastname: de Béeck
authors.forename: Severine
authors.initials: S
authors.lastname: Vermeire
authors.forename: Kristel
authors.initials: K
authors.lastname: Van Steen
authors.forename: Georges
authors.initials: G
authors.lastname: Michiels
authors.forename: Vera
authors.initials: V
authors.lastname: Ballet
authors.forename: Paul
authors.initials: P
authors.lastname: Rutgeerts
authors.forename: Xavier
authors.initials: X
authors.lastname: Bossuyt
mesh_terms: D001324:Autoantigens / Q000276:immunology*; D015153:Blotting, Western; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000276:immunology; D003424:Crohn Disease / Q000276:immunology; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D040081:Protein Array Analysis
chemical_list: D001324:Autoantigens