Autoantibodies to tissue transglutaminase are sensitive serological parameters for detecting silent coeliac disease in patients with Type 1 diabetes mellitus

Aims To investigate the clinical significance of the determination of IgA a ntibodies to tissue transglutaminase (tTG) for the detection of silent coel iac disease in patients with Type 1 diabetes mellitus. Methods A total of 520 patients with diabetes (median age 14.2 years, range 1-27) were tested for IgA antibodies to tTG (IgA anti-tTG, ELISA), endomys ium (EmA, indirect immunofluoresence) and gliadin (IgA-AGA, enzyme immunome tric assay) after ruling out IgA deficiency. Results The prevalence of IgA anti-tTG among patients with diabetes was 4.4 % (23 of 520), and that of EmA and IgA-AGA 3.5% (18 of 520, respectively). The coefficient of agreement between IgA antitTG and EmA was high (Cohen's kappa = 0.87, P < 0.001). Thirteen of the 23 IgA anti-tTG-positive patients underwent duodenal biopsy. Coeliac disease was confirmed in nine of 13 pat ients. One of them was negative for EmA and AGA, but positive for IgA anti- tTG. Retrospective annual determinations up to 8 years in six IgA anti-tTG- positive patients showed both permanent and transient elevations of the ser ological markers. Conclusions These data show that a positive IgA antibody test to tTG is a m ore sensitive parameter than EmA for silent coeliac disease in patients wit h diabetes. Confirmatory small bowel biopsy, however, remains necessary for diagnosis as some patients with positive antibodies may be without histolo gical changes.