Our objective was to determine whether high serologic IgA tissue transglutaminase antibodies (TTGA) are exclusively associated with celiac disease (CD).
IgA TTGA are found in the serum of most individuals with CD. This serologic marker is used to screen individuals with suspected CD for duodenal biopsy, the gold standard of CD diagnosis. Data suggest strongly positive IgA TTGA ≥100 units are highly specific for CD histopathology in pediatric patients and may be sufficient for diagnosis.
Records of adult and pediatric subjects in the celiac study at the University of Utah and University of California Irvine were reviewed for strongly positive TTGA. Pathology reports from duodenal biopsies of subjects with IgA TTGA ≥100 units were graded as 0 to 3 by modified Marsh criteria.
From a pool of 1882 subjects with IgA TTGA assayed, 208 had IgA TTGA ≥100 units. Seventy-six of these, including 28 children and 48 adults, also had duodenal biopsies. Villous atrophy (Marsh 3 histopathology) was found on biopsy in 73 (96%) of these subjects. The remaining 3 subjects had intermediate Marsh histology. One (Marsh 1) had a complete serologic response to a gluten-free diet and 2 had Marsh 2 lesions and positive endomysium, making early CD most likely.
IgA TTGA ≥100 units occur almost exclusively in the setting of Marsh 3 duodenal histopathology in adults and children. Rare cases without villous atrophy were marked by intermediate Marsh changes suggestive of early CD. IgA TTGA ≥100 arbitrary units indicate duodenal changes consistent with CD.