Detection of autoantibodies against tissue transglutaminase in patients with celiac disease and dermatitis herpetiformis

OBJECTIVE: Endomysial autoantibodies (EmA) are specific for celiac disease. The target antigen has been identified as tissue tranglutaminase (tTG). Ou r aim was to study the accuracy of a newly developed enzyme-linked immunoso rbent assay (ELISA) for easy detection of tTG autoantibodies. METHODS: Thirty-one sera from patients with histologically proven celiac di sease and 23 healthy controls were examined for EmA using monkey esophagus and human umbilical cord as substrate. IgA-tTG autoantibodies were determin ed by newly developed ELISA. Additionally, sera from patients with dermatit is herpetiformis (n = 20), inflammatory bowel disease (IBD; n = 32), chroni c liver disease (n = 36), and diabetes mellitus (n = 19) were tested. RESULTS: The sensitivity of the tTG autoantibody ELISA accounted for 90% de tection in patients with untreated celiac disease. The specificity was 76% owing to positive values in the lower range in patients with IBD (15%), chr onic liver disease (36%), and diabetes (22%), all of whom were negative for EmA. In dermatitis herpetiformis patients 90% were EmA-positive. Of these, only 47% showed elevated tTG autoantibodies. Preincubation of sera from de rmatitis patients with tTG abolished immunofluorescent staining of endomysi al structures. CONCLUSION: Detection of mid- to high-titer tTG autoantibodies is highly sp ecific for celiac disease. However, in the low-titer range, overlap exists with liver disease, IBD, and diabetes. Tissue transglutaminase autoantibodi es may evolve as a new screening and follow-up method for celiac disease. A lthough tTG seems to be a major autoantigen in dermatitis herpetiformis, th e low sensitivity of both tTG ELISA and immunofluorescence using human umbi lical cord suggests differential involvement of tTG in this disease. (C) 20 00 by Am. Cell. of Gastroenterology.