Predictive capacity of anti-tissue-transglutaminase IgA antibodies to identify intestinal villous atrophy in persons with celiac disease. An observational study at a referral center in Mexico City

Introduction and aims Celiac disease (CD) is an autoimmune enteropathy secondary to gluten exposure, diagnosed through serology and duodenal biopsy. The predictive role of anti-tissue-transglutaminase antibody (aTG IgA) levels ≥ 10 times the upper limit of normal (ULN) in the degree of villous atrophy in duodenal biopsies in patients with CD has recently been evaluated. Our aim was to determine the predictive capacity of aTG IgA levels ≥ 10 times the ULN for detecting intestinal villous atrophy (IVA) in patients with CD. Materials and methods A retrospective, observational study was conducted on patients with suspected CD who underwent endoscopy with duodenal biopsy at a referral center in Mexico City. Demographic, clinical, and final diagnosis variables were registered. Descriptive statistics and an ROC analysis were performed, evaluating different cutoff points of aTG IgA antibodies as IVA predictors. Results The study included 366 patients (median age of 51 years). CD was diagnosed in 53 of the cases (14.5%). A total of 107 cases were classified as Marsh 3a-3c, and their main diagnoses were CD (45.8%), small intestinal bacterial overgrowth (23.4%), and tropical sprue (16.8%). The specificity of levels ≥ 10 times the ULN was 100% for Marsh 3a-3c, with 17.9% sensitivity, 74.7% NPV, and 100% PPV. The AUC was 70%, with an optimum threshold ≥ 3.3 U/mL ULN (45.3% sensitivity, 89.2% specificity). Conclusion Levels of aTG IgA ≥ 10 times the ULN are highly specific but have low sensitivity for predicting IVA in Mexican patients with CD, whereas using levels ≥ 3 times the ULN improves sensitivity, without compromising specificity.