Antibodies against human tissue transglutaminase and endomysium in diagnosing and monitoring coeliac disease.
BACKGROUND
Coeliac disease (CD) patients often present a variety of uncharacteristic symptoms and therefore sensitive and specific screening tests are needed as an aid in making an accurate diagnosis. A recently developed ELISA, using human recombinant tissue transglutaminase (tTG) as antigen, was evaluated for its significance in the diagnosis of CD. The patient's compliance to a gluten-free diet and the serological reaction during gluten challenge were also monitored. The results were compared with IgA-endomysium antibody (EMA) results.


METHODS
Sera previously collected from 365 patients (0.4-76 years) with jejunal biopsy on a gluten-containing diet and from 41 patients on a gluten-free diet or challenge were tested for IgA anti-human tTG antibodies (IgA tTG ab) with Celikey (Pharmacia Diagnostics). The study population comprised 208 CD patients and 157 controls. The diagnostic performance and cut-off for the assay were estimated with ROC analysis. EMA was analysed by indirect immunofluorescence microscopy on cryostat sections of monkey oesophagus.


RESULTS
200/208 patients with CD had positive IgA tTG ab (median >100 U/ml), while only 1/157 of the control patients were positive (median 1.67 U/ml). The area under the ROC curve was 98.3% and the sensitivity and specificity of the test were 96% and 99% for the study population. Only 4/365 patients (1%) presented discordant IgA tTG ab and EMA results, 2 of them had only IgA tTG ab and 2 only EMA. The IgA tTG ab levels and the EMA titres were closely correlated to the duration of gluten-free diet and gluten challenge, respectively.


CONCLUSIONS
IgA tTG ab can be used as an accurate observer-independent alternative to EMA in diagnosing or monitoring CD.
Bürgin-Wolff
A
A
Institute for Coeliac Disease, Liestal, Switzerland. a.buergin-wolff@bluewin.ch
Dahlbom
I
I
Hadziselimovic
F
F
Petersson
C J
CJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000032:analysis / Q000276:immunology*; D016022:Case-Control Studies; D002446:Celiac Disease / Q000097:blood / Q000175:diagnosis* / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D004032:Diet; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005500:Follow-Up Studies; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis / Q000276:immunology; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D011336:Probability; D011446:Prospective Studies; D012372:ROC Curve; D012016:Reference Values; D012680:Sensitivity and Specificity; D011503:Transglutaminases / Q000032:analysis / Q000276:immunology*
D001323:Autoantibodies; D007070:Immunoglobulin A; D011503:Transglutaminases