Israel Medical Association Journal

Background: Screening for celiac disease is based on the sequential evaluation of serologic tests and intestinal biopsy; an optimal screening protocol is still under investigation. The screening policy of one of the main healthcare providers in Israel (Maccabi) consists of measuring total immunoglobulin A and tissue transglutaminase IgA[1] antibodies and confirming positive results by endomysial antibodies. For IgA-deficient patients antigliadin IgG is measured.

Objectives: To evaluate the use of tTGA[2] as a first-level screening test in patients suspected of having celiac disease

Methods: The results of tTGA and EMA[3] tests over a 3 month period were obtained from the laboratory computer. Letters were sent to the referring physicians of patients with positive tests, requesting clinical information and small intestinal biopsy results. tTGA was performed using an anti-guinea pig tTG-IgA enzyme-linked immunosorbent assay kit.

Results: Overall, 2,505 tTGA tests were performed: 216 (8.6%) were tTGA-positive of which 162 (75%) were EMA-negative (group 1) and 54 (25%) EMA-positive (group 2). Clinical information was obtained for 91 patients in group 1 and 32 in group 2. Small intestinal biopsy was performed in 33 (36%) and 27 patients (84%) in groups 1 and 2, respectively. Celiac disease was diagnosed in 4 biopsies (12%) in group 1 and 23 (85%) in group 2 (P < 0.0001). The positive predictive value was 45% for tTGA and 85% for EMA.

Conclusions: Symptomatic patients with positive tTGA and negative EMA have a low rate of celiac disease compared to those who are tTGA-positive and EMA-positive. Confirmation with EMA is advised when tTGA is performed as a first-level screening for suspected celiac disease.

Background: Celiac disease is common in both children and adults. Small intestinal biopsy is mandatory for establishing a diagnosis. Anti-endomysial antibodies, detected by immunofluorescence, have a sensitivity and specificity close to 100% in the diagnosis of CD[1]. Recently, tissue transglutaminase has been identified as the target autoantigen of antibodies against endomysium, and TTG[2] antibodies are comparable to EMA-IMF[3] in the diagnosis of CD.

Objective: To evaluate a new enzyme-linked immunosorbent assay kit for EMA, compared to EMA-IMF and TTG antibodies in the diagnosis of CD.

Methods: Our study population included all subjects with positive EMA-IMF who underwent intestinal biopsy (n=21). From the same sera, TTG antibodies and EMA-ELISA[4] were determined, and all antibody results were compared to the biopsy findings.

Results: EMA-IMF was able to predict biopsy findings of CD in 19 of 21 cases (90.5%). When patients with biopsy findings compatible with CD and positive EMA-IMF (n=19) were tested for EMA-ELISA and TTG antibodies, 18 of the 19 were positive for both EMA-ELISA and TTG antibodies. A significant correlation was found between EMA-ELISA and TTG antibody titers (r = 0.74, P < 0.001).

Conclusions: Our study demonstrates that EMA-ELISA is comparable to TTG antibodies in the diagnosis of CD, and supports the use of EMA-ELISA as a serologic marker for this disease.

Background: Anti-endomysial antibodies are sensitive and specific markers for celiac disease. This antibody has recently been identified as an antibody to tissue transglutaminase, an enzyme that cross-links and stabilizes extracellular matrix proteins.

Objectives: To evaluate the clinical usefulness of an enzyme-linked immunoassay for anti-transglutaminase antibodies, and to compare the results with those of AEA, the current gold standard serological test for celiac disease.

Methods: Serum samples were collected from 33 patients with biopsy-proven celiac disease and AEA tests were performed. Control samples for anti-transglutaminase were obtained from 155 patients. An ELISA test for immunoglobulin A anti-transglutaminase utilizing guinea pig liver transglutaminase was developed and performed on all sera.  Cutoff values for the test were performed using logistic regression and receiver operating curves analysis.

Results: An optical density cutoff value of 0.34 was established for the assay. The mean value was 0.18±0.19 optical density for controls, and 1.65±1.14 for patients with celiac disease (P<0.001). Sensitivity and specificity of the assay were both 90%, while AEA had a sensitivity and specificity of 100% and 94%, respectively.

Conclusions: A tissue transglutaminase-based ELISA test is both sensitive and specific for  detection of celiac disease.

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AEA = anti-endomysial antibody