title: Immunoglobulin A deficiency in celiac disease in the United States.
abstract: OBJECTIVE
  Multiple European studies report increased prevalence of selective immunoglobulin A deficiency (SIgAD) and partial immunoglobulin A deficiency (PIgAD) in patients with celiac disease (CD). However; prospective data representing North American adults are lacking. While SIgAD precludes the use of IgA-tissue-transglutaminase antibody (IgA-tTG), the effect of PIgAD on IgA-tTG sensitivity is not well documented. We aim to determine the prevalence and impact of IgA deficiency on CD presentation and diagnosis in North American adult patients.
  
  
  METHODS
  We reviewed 1000 consecutive patients undergoing IgA-tTG testing and 243 healthy controls. Eligible sera were tested for IgA-tTG, serum immunoglobulins, and IgA/IgG-deamidated gliadin peptide (IgA/IgG-DGP).
  
  
  RESULTS
  Prevalence of SIgAD was marginally higher in patients with CD (1.9%) compared with healthy controls (0.4%, P = 0.24) and patients without CD (0.7%, P = 0.173). Prevalence of PIGAD was similar in patients with CD (4.8%) compared with healthy controls (5.9%, P = 0.57) and patients without CD (7.2%, P = 0.22). One (16.7%) of 6 patients with CD with SIgAD and all 15 (100%) with PIGAD tested IgA-tTG positive prior to gluten-free diet initiation. Patients with CD with SIGAD showed lower frequency of gastrointestinal symptoms (33% vs 82%, P = 0.01) and more co-morbid autoimmune disease (67% vs 23%, P = 0.03) when compared with patients with CD with normal IgA.
  
  
  CONCLUSIONS
  The prevalence of SIgAD in North American patients with CD is comparable with European data but not significantly different than control populations. Patients with CD with SIgAD exhibit decreased IgA-tTG sensitivity and lack of gastrointestinal symptoms. PIgAD is common in patients with gastrointestinal disorders but does not alter CD presentation or IgA-tTG sensitivity.
authors.affiliation: Celiac Center, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.|Division of Digestive Diseases, University of Mississippi Medical Center, Jackson, Mississippi, USA.
authors.forename: Kumar
authors.initials: K
authors.lastname: Pallav
authors.affiliation: Celiac Center, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Hua
authors.initials: H
authors.lastname: Xu
authors.affiliation: Celiac Center, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Leffler
authors.affiliation: Celiac Center, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Toufic
authors.initials: T
authors.lastname: Kabbani
authors.affiliation: Celiac Center, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Ciaran P
authors.initials: CP
authors.lastname: Kelly
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002446:Celiac Disease / Q000150:complications* / Q000503:physiopathology; D005260:Female; D006801:Humans; D017098:IgA Deficiency / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology*; D007070:Immunoglobulin A / Q000276:immunology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D011503:Transglutaminases / Q000276:immunology; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D007070:Immunoglobulin A; D011503:Transglutaminases
keywords: IgA deficiency; United States; celiac disease; transglutaminases