Comparison of Anti-Transglutaminase Elisas and an Anti-Endomysial Antibody Assay in the Diagnosis of Celiac Disease: A Prospective Study (Clinical Immunology) (Clinical Report‪)‬

The recent introduction of an anti-tissue transglutaminase (anti-tTG) [4] assay in the diagnostic work-up of celiac disease (CD) has offered a simpler means for evaluating suspected CD and selecting patients to undergo intestinal biopsy (1). Pretreatment of CD sera with tTG eliminated the endomysial staining pattern in human umbilical cord, suggesting that tTG could be the previously unknown endomysium autoantigen (2,3). Furthermore, reticulin, endomysial, and jejunal antibodies detected transglutaminase in primate tissues, suggesting that these tissue antibodies, and the anti-transglutaminase antibodies themselves, could be identical (4). Consequently, it has been suggested that the simpler and less expensive ELISA developed to detect the presence of serum anti-tTG autoantibodies could replace the immunofluorescence technique traditionally used for the detection of antiendomysial antibodies (EmAs) (1-3,5,6). Recent reports, however, have shown a high frequency of false-positive results with the most widely used anti-tTG ELISA, which is based on guinea pig tTG (gp-tTG) as the antigen, in patients with liver diseases (7,8), and we found false-positive results in patients with lymphoproliferative disease (9). Better results have been reported with a new anti-tTG ELISA based on human tTG (h-tTG) as the antigen (10). However, few studies have evaluated the diagnostic accuracy of this new anti-h-tTG ELISA, and almost all the studies on the anti-tTG assay have considered preselected groups of patients and not consecutive individuals with suspected CD. The aim of the present prospective study was to compare the diagnostic accuracy of the EmA assay and two commercially available anti-tTG ELISAs, one based on gp-tTG and the other on h-tTG as antigen, in consecutive patients prospectively investigated for suspected CD, all of whom underwent intestinal biopsies.