Elevated Serum Tissue Transglutaminase Antibodies in Children With Eosinophilic Esophagitis.

OBJECTIVES:This study compared the clinical and histopathological characteristics of children with eosinophilic esophagitis (EoE) and elevated anti-transglutaminase (TTG Ab) with those with EoE and normal TTG Ab titres. METHODS:Single-center chart and blinded histopathological review of patients diagnosed with EoE for a 4-year period, who had esophageal and duodenal biopsies taken at time of endoscopy, and TTG Ab measured within 6 months of biopsy. Patients with histology-proven CD were excluded. RESULTS:Elevated TTG Ab was present in 19/34 (54%) of the study cohort, representing 23% of all patients diagnosed with EoE during the study period. Eight had titers >6× upper limit of normal (ULN) and 4 had >10× ULN. TTG Ab-positive patients were classified as having either potential CD with (n = 3, 16%) and without lymphocytic duodenosis (LD; n = 12, 63%), and no CD (n = 4, 21%) on human leukocyte antigen typing. There was an increase in duodenal eosinophils in patients with elevated TTG Ab (P = 0.01), which remained when patients with LD were excluded (P = 0.018). Of 19 patients with EoE and elevated TTG Ab, 5 responded to elimination diet involving exclusion of wheat, including 2 with a sole wheat trigger and TTG Ab >10× ULN that were CD-associated human leukocyte antigen-negative. CONCLUSIONS:Serum TTG Ab was elevated in almost one-quarter of our total EoE cohort, and at least 20% of these patients did not have potential CD, suggesting EoE is a heterogeneous disease with differing immune mechanisms activated in some patients. These findings also support routine esophageal biopsy during upper endoscopy in children with elevated TTG Ab.