title: Correlation between IgA tissue transglutaminase antibody ratio and histological finding in celiac disease.
abstract: OBJECTIVE
  Positivity of both immunoglobulin A anti-tissue transglutaminase (TTG) and anti-endomysium antibodies (EMA) has a positive predictive value of nearly 100% for celiac disease (CD). The objective of the present study was to evaluate whether patients of any age, with high pretest probability of CD and high titre of anti-TTG and EMA positivity, have a high probability of intestinal damage and may not require the biopsy for final diagnosis.
  
  
  METHODS
  A retrospective analysis of 412 consecutively referred patients, age range 10 months to 72 years, who underwent small-bowel biopsy for suspicion of CD and positivity to both anti-TTG and EMA, was performed at 4 Italian centers. Biopsies were evaluated independently by 2 pathologists using Marsh modified classification; in cases of dissimilar results, a third pathologist examined the biopsy. The final histological finding diagnosis was expressed as the prevalent or highest score assigned by the pathologist board.
  
  
  RESULTS
  Three hundred ninety-six patients (96.1%) had histological findings consistent with CD (grade 2 and 3a, 3b, or 3c of modified Marsh classification). An anti-TTG ratio ≥ 7 was able to identify with the 3 assays used (Celikey, anti-TTG immunoglobulin A, EuTTG) all of the patients with significant mucosal damage (Marsh ≥ 2) independent of age and sex; specificity and positive predictive value were 100%. An anti-TTG ratio >20 was more specific (99.8%) for identification of patients with villous atrophy (Marsh 3 a, b, or c).
  
  
  CONCLUSIONS
  Patients with positivity of anti-TTG ≥ 7-fold cutoff, confirmed by positivity to EMA, have a high-degree probability of duodenal damage. In selected conditions, a duodenal biopsy may be avoided and a confirmed greatly positive anti-TTG result could be the basis to prescribe a gluten-free diet.
authors.affiliation: Department of Laboratory Medicine, Biochemistry Laboratory, Riuniti Hospital, Bergamo, Italy. mgalessio@ospedaliriuniti.bergamo.it
authors.forename: Maria G
authors.initials: MG
authors.lastname: Alessio
authors.forename: Elio
authors.initials: E
authors.lastname: Tonutti
authors.forename: Ignazio
authors.initials: I
authors.lastname: Brusca
authors.forename: Antonella
authors.initials: A
authors.lastname: Radice
authors.forename: Lisa
authors.initials: L
authors.lastname: Licini
authors.forename: Aurelio
authors.initials: A
authors.lastname: Sonzogni
authors.forename: Ada
authors.initials: A
authors.lastname: Florena
authors.forename: Eugenio
authors.initials: E
authors.lastname: Schiaffino
authors.forename: Wally
authors.initials: W
authors.lastname: Marus
authors.forename: Sandro
authors.initials: S
authors.lastname: Sulfaro
authors.forename: Danilo
authors.initials: D
authors.lastname: Villalta
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D002446:Celiac Disease / Q000145:classification / Q000276:immunology* / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D004386:Duodenum / Q000473:pathology*; D005260:Female; D019204:GTP-Binding Proteins / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D007223:Infant; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000276:immunology*; D011237:Predictive Value of Tests; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D012189:Retrospective Studies; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D011503:Transglutaminases / Q000276:immunology*; D055815:Young Adult
chemical_list: D007070:Immunoglobulin A; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins