title: Antibodies to deamidated gliadin peptide in diagnosis of celiac disease in children.
abstract: OBJECTIVE
  Determination of antibodies to synthetic deamidated gliadin peptides (anti-DGPs) may work as an alternative or complement the commonly used test for tissue transglutaminase antibodies (TGA) in the diagnosis of celiac disease (CD). We analyzed the performance of a time-resolved immunofluorometric anti-DGP assay (TR-IFMA) in the diagnosis of CD in children and also retrospectively analyzed the appearance of anti-DGP antibodies before TGA seroconversion.
  
  
  METHODS
  The study included 92 children with biopsy-confirmed CD. Serum samples were taken at the time or just before the clinical diagnosis. The control group comprised 82 TGA-negative children who were positive for human leucocyte antigen-DQ2 or -DQ8.
  
  
  RESULTS
  Based on receiver operating characteristic curves, the optimal cutoff value for immunoglobulin (Ig) A anti-DGP positivity was 153 arbitrary units (AUs) with a sensitivity of 92.4% and specificity of 97.6% and that for IgG anti-DGP 119 AU, with a sensitivity of 97.8% and specificity of 97.6%. All 92 children with CD were either IgA or IgG anti-DGP positive at the time of diagnosis. Sera from 48 children with CD were also analyzed retrospectively before the diagnosis. Anti-DGP antibodies preceded TGA positivity in 35 of the 48 children with CD and appeared a median of 1 year earlier.
  
  
  CONCLUSIONS
  The TR-IFMA assay for detecting anti-DGP antibodies shows high sensitivity and specificity for the diagnosis of CD in children. In a majority of our study population, anti-DGP seropositivity preceded TGA positivity, indicating that earlier detection of CD may be possible by monitoring anti-DGP antibodies frequently in genetically susceptible children.
authors.affiliation: *Department of Clinical Microbiology †Department of Pediatrics, University of Eastern Finland ‡Department of Pediatrics and Adolescent Medicine, University of Turku, Turku §A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio ||Department of Pediatrics, University of Oulu and Oulu University Hospital, Oulu ¶Children's Hospital, University of Helsinki, Helsinki #Institute of Clinical Medicine, University of Helsinki, Helsinki, Finland.
authors.forename: Anne
authors.initials: A
authors.lastname: Lammi
authors.forename: Pekka
authors.initials: P
authors.lastname: Arikoski
authors.forename: Satu
authors.initials: S
authors.lastname: Simell
authors.forename: Tuure
authors.initials: T
authors.lastname: Kinnunen
authors.forename: Ville
authors.initials: V
authors.lastname: Simell
authors.forename: Sari
authors.initials: S
authors.lastname: Paavanen-Huhtala
authors.forename: Ari
authors.initials: A
authors.lastname: Hinkkanen
authors.forename: Riitta
authors.initials: R
authors.lastname: Veijola
authors.forename: Mikael
authors.initials: M
authors.lastname: Knip
authors.forename: Jorma
authors.initials: J
authors.lastname: Toppari
authors.forename: Outi
authors.initials: O
authors.lastname: Vaarala
authors.forename: Olli
authors.initials: O
authors.lastname: Simell
authors.forename: Jorma
authors.initials: J
authors.lastname: Ilonen
mesh_terms: D000293:Adolescent; D002446:Celiac Disease / Q000097:blood* / Q000175:diagnosis* / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D042241:Early Diagnosis; D005260:Female; D015200:Fluoroimmunoassay; D019204:GTP-Binding Proteins / Q000276:immunology; D005983:Glutens / Q000276:immunology*; D059848:HLA-DQ alpha-Chains / Q000235:genetics; D059866:HLA-DQ beta-Chains / Q000235:genetics; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood*; D007223:Infant; D008297:Male; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D012372:ROC Curve; D012189:Retrospective Studies; D012698:Serologic Tests; D013997:Time Factors; D011503:Transglutaminases / Q000276:immunology
chemical_list: D059848:HLA-DQ alpha-Chains; D059866:HLA-DQ beta-Chains; C069050:HLA-DQA1 antigen; C069051:HLA-DQB1 antigen; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D005983:Glutens; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins