IGA ANTIENDOMYSIAL ANTIBODY AS A SCREEN FOR CELIAC DISEASE

Abstract

This study sought to determine whether a noninvasive serological marker for celiac disease, the IgA antiendomysial antibody (IgA-EMA), could be used to screen for unrecognized celiac disease in children previously diagnosed with insulin dependent diabetes mellitus (IDDM). Subjects included 236 volunteers from the diabetes clinic at the Alberta Children's Hospital (ACH) whose age ranged from 1 to 18 years. control patients consisted of an additional 55 children from 1 to 16 years of age, referred to the outpatient gastrointestinal (GI) clinic for investigation of chronic diarrhea or suspected malabsorption and who required an intestinal biopsy. Blood was assayed for total serum IgA and IgA-EMA (Imucore, Edmonton, AB). All IgA-EMA positive diabetic patients were asked to consent to a jejunal biopsy. Of 236 diabetic patients, none were IgA deficient, and 19 were positive for IgA-EMA (8%). Of the IgA-EMA positive diabetic patients, 11 of 15 patients who underwent jejunal biopsy had histological evidence of celiac disease, two declined biopsy and in two biopsy is pending. With careful questioning, only 2 of the 11 diabetic patients had symptoms suggestive of celiac disease. The estimated prevalence of celiac disease in this diabetic population (4.6%) is consistent with the literature. Of the 55 GI controls, 3 were positive for IgA-EMA and had biopsies consistent with celiac disease. Three patients were found to be IgA deficient, one of whom had a biopsy consistent with celiac disease. Of the 49 IgA-EMA negative patients 1 had a biopsy diagnostic of celiac disease and 48 had biopsies not consistent with celiac disease. For the diagnosis of celiac disease, the IgA-EMA test has a sensitivity of 87% (14/16) and a specificity of 92% (50/54) in patients who underwent intestinal biopsy. These findings provide a strong rationale for the proposal that children with IDDM should be routinely screened for celiac disease using total IgA and the IgA-EMA assay, and that seropositive patients should undergo jejunal biopsy. However, the finding of a negative IgA-EMA in a symptomatic patient underscores the necessity of the jejunal biopsy as the gold standard for the diagnosis of celiac disease.