title: Serologic assay for diagnosis of celiac disease based on a patient-derived monoclonal antigliadin antibody.
abstract: OBJECTIVE
  Patients with celiac disease can be identified based on the detection of serum antibodies to deamidated gliadin peptides (DGPs). Recombinant human monoclonal antibodies (hmAb) against gliadin are produced by cloning antibody genes from single IgA-producing plasma cells isolated from lesions of patients with celiac disease. We developed an assay to identify patients with celiac disease based on the ability of antibodies from their serum to inhibit the binding of a gliadin-specific hmAb (1002-1E03) to a specific peptide antigen (inhibition assay).
  
  
  METHODS
  We selected 2 peptides (a 34-mer and a 26-mer) found in ω-gliadins and low-molecular-weight glutenins that had been identified as specific targets of the hmAb 1002-1E03 from a digest of gliadin treated by transglutaminase 2. These peptides contained repeat sequence motifs; their interaction with hmAb 1002-1E03 was assessed in an amplified luminescent proximity homogeneous inhibition assay. We also tested peptides we created that included 3 repeated sequence motifs. Serum samples from untreated patients diagnosed with celiac disease (n = 106) and 2 control groups (198 blood donors, 151 patients with Crohn's disease) were analyzed using the assay, as well as in conventional commercial assays that measure IgA against transglutaminase 2 (TG2) or IgG against DGP.
  
  
  RESULTS
  In our inhibition assays, the 34-mer peptide showed the best results, and identified patients with celiac disease with 86.8% sensitivity and 98.6% specificity. Its diagnostic accuracy was comparable with that of commercial anti-DGP IgG (sensitivity, 87.9%; specificity, 98.0) and anti-TG2 IgA (sensitivity, 81.1%; specificity, 98.9) assays, and it detected most of the patients with anti-TG2 IgA-negative celiac disease without a significant decrease in specificity. Combined use of the anti-ω34 and the anti-TG2 assays produced specificity and sensitivity values of 95.3% and 98.0%, respectively.
  
  
  CONCLUSIONS
  We developed an antigliadin inhibition assay that identifies patients with celiac disease with high levels of specificity and sensitivity. It may prove useful as an adjunct to the current assay for anti-TG2 IgA.
authors.affiliation: Centre for Immune Regulation and Department of Immunology, University of Oslo and Oslo University Hospital-Rikshospitalet, Oslo, Norway.
authors.forename: Øyvind
authors.initials: Ø
authors.lastname: Steinsbø
authors.affiliation: Centre for Immune Regulation and Department of Immunology, University of Oslo and Oslo University Hospital-Rikshospitalet, Oslo, Norway.
authors.forename: Siri
authors.initials: S
authors.lastname: Dørum
authors.affiliation: Centre for Immune Regulation and Department of Immunology, University of Oslo and Oslo University Hospital-Rikshospitalet, Oslo, Norway; Department of Gastroenterology, Oslo University Hospital-Rikshospitalet, Oslo, Norway.
authors.forename: Knut E A
authors.initials: KE
authors.lastname: Lundin
authors.affiliation: Centre for Immune Regulation and Department of Immunology, University of Oslo and Oslo University Hospital-Rikshospitalet, Oslo, Norway. Electronic address: l.m.sollid@medisin.uio.no.
authors.forename: Ludvig M
authors.initials: LM
authors.lastname: Sollid
mesh_terms: D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000097:blood / Q000276:immunology*; D002446:Celiac Disease / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D005260:Female; D019204:GTP-Binding Proteins / Q000276:immunology*; D005903:Gliadin / Q000276:immunology*; D005983:Glutens / Q000737:chemistry / Q000276:immunology; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood* / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000276:immunology; D011485:Protein Binding / Q000276:immunology; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D012680:Sensitivity and Specificity; D011503:Transglutaminases / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D010455:Peptides; D005983:Glutens; D005903:Gliadin; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins; C037302:glutenin
keywords: AlphaLISA; ELISA; Epitope; Gluten