Comparison of a tissue transglutaminase ELISA with the endomysium antibody test in the diagnosis of gluten-sensitive enteropathy.
Tissue transglutaminase (tTG) has recently been found to be the major if not the only autoantigen of gluten-sensitive enteropathy (GSE). To further determine the significance of this finding for diagnostic (screening) and follow-up purposes, we performed tTG-based ELISAs, and compared the results to the endomysium antibody test (EMA). We examined 120 serum samples from patients with celiac disease (CD) including 72 on a gluten-free diet (GFD) and eleven on a gluten challenge, 47 with dermatitis herpetiformis (DH) including 16 on a GFD and one on a gluten challenge, 96 with non-CD gastrointestinal diseases, and 117 with others; i.e. 380 serum samples altogether. Follow-up sera from 13 patients were included. Results of an ELISA with guinea pig liver tTG were compared with the EMA test using monkey esophagus. Inhibition of endomysial staining was performed with sera positive on the EMA test but negative with the guinea pig tTG ELISA. The specificity and sensitivity of the tTG ELISA are high (98.6% and 92.5%). The serum IgA antibody titers against tTG decrease after introduction of a GFD. In one case, endomysial staining could not be inhibited. Our results show that the guinea pig tTG ELISA is suitable for use as a simple diagnostic screening and follow-up method for GSE. Further studies are necessary to identify possible additional minor antigens in GSE.