title: [Serological screening of relatives of celiac disease patients: antiendomysium antibodies, anti-tissue transglutaminase or both?].
abstract: BACKGROUND
  Celiac disease is the most common intestinal disorder of caucasian populations and presents a prevalence of 8% to 18% between the relatives of patients. The anti-endomysial (IgA-EmA) and anti-tissue transglutaminase antibodies (IgA-tTG) have represented an important non invasive and sensitivity method of screening and diagnosis of celiac disease in risk groups and populations.
  
  
  OBJECTIVE
  To investigate the prevalence of IgA-EmA and IgA-tTG antibodies in relatives of celiac patients and verify the degree of concordance between them.
  
  
  METHODS
  One hundred and seventy seven relatives of celiac patients (76(feminino); 101(masculino); 2-79 years) and 93 healthy individuals were evaluated (34(feminino); 59(masculino); 2-71 years). IgA-EmA were detected by indirect immunofluorescence, with human umbilical cord as substrate, while anti-IgA-tTG titers were measured by enzyme-linked immunosorbent assay (ELISA), using commercial kit.
  
  
  RESULTS
  Total positivity to antibodies in relatives of celiac patients was of 21% (37/177), and showed significant difference compared to control group (0%; 0/93). Twelve percent (21/177) of celiac disease relatives were positive to IgA-EmA, 13.56% (24/177) to IgA-tTG, and 4.52% (8/177) to both assays simultaneously. The concordance between both methods was 83.6% (148/177) and the discordance was 16.4% (29/177), with a positive and significant correlation (r = 0.435). Among the concordant results, 79.1% (140/177) were negative and 4.52% (8/177) were positive to both antibodies. Among the discordant results, 7.34% (13/177) were positive to IgA-EmA and negative to IgA-tTG, while 9.04% (16/177) were negative to IgA- EmA and positive to IgA-tTG.
  
  
  CONCLUSIONS
  Although the high positivity to IgA-EmA and IgA-tTG emphasizes the importance of the serological screening in relatives of celiac patients, the discordances detected in this study showed that the use of only one method can lead to false negative results. Consequently these relatives will not be submitted to intestinal biopsy to confirm the diagnosis of celiac disease, and to the correct and earlier treatment.
authors.affiliation: Laboratório de Imunopatologia, Hospital de Clínicas, Universidade Federal do Paraná, Curatiba, PR. shirley@ufpr.br
authors.forename: Shirley Ramos da Rosa
authors.initials: SR
authors.lastname: Utiyama
authors.forename: Flávia Raphaela
authors.initials: FR
authors.lastname: Nass
authors.forename: Lorete Maria da Silva
authors.initials: LM
authors.lastname: Kotze
authors.forename: Renato Mitsunori
authors.initials: RM
authors.lastname: Nisihara
authors.forename: Altair Rogério
authors.initials: AR
authors.lastname: Ambrosio
authors.forename: Iara Taborda de
authors.initials: IT
authors.lastname: Messias-Reason
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D016022:Case-Control Studies; D002446:Celiac Disease / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011503:Transglutaminases / Q000097:blood* / Q000276:immunology
chemical_list: D001323:Autoantibodies; D007070:Immunoglobulin A; D011503:Transglutaminases