Anti-tissue transglutaminase antibodies (IgA and IgG) in both Crohn´s disease and autoimmune diabetes.

OBJECTIVE: a strong association has been observed between celiac disease, generally its silent clinical form, and autoimmune disorders. A potential correlation with inflammatory bowel disease has also been suggested. Anti-tissue transglutaminase antibodies have been detected in Crohn´s disease. We investigated the prevalence of celiac disease in patients with autoimmune diabetes and in Crohn´s disease patients and also evaluated the correlation between anti-transglutaminase antibody positivity and the clinical status of these diseases.
METHODS: anti-tissue transglutaminase and anti-endomysium antibodies were assessed by enzyme-linked immunosorbent assay and indirect immunofluorescence, respectively. Upper digestive endoscopy and duodenal biopsy were indicated for cases with positive serology.
RESULTS: anti-transglutaminase antibodies were detected in five diabetic patients (prevalence of 11.1%), only one serum sample was positive for IgG isotypes. Nine of thirty-three patients with Crohn´s disease had low positive levels for IgA anti-transglutaminase. Antiendomysium antibodies were detected only in celiac patients. Celiac disease was confirmed in all diabetic patients submitted to duodenal biopsies who presented both anti-transglutaminase and anti-endomisyum antibodies positivity. In Crohn´s disease, its clinical status and the diagnosis of celiac disease were not associated with positiveanti-transglutaminase result.
CONCLUSIONS: the prevalence of celiac disease was high in diabetic patients. Anti-tissue transglutaminase antibodies were sensitive and specific markers of celiac disease in this diabetic group, while these antibodies were of limited value for celiac disease screening in patients with Crohn´s disease.