Serum transglutaminase antibodies do not always detect the persistent villous atrophy in patients with celiac disease on a gluten-free diet

Background and aim: Serum transglutaminase antibodies (tTGs) are used for celiac disease screening and to monitor celiac disease patients on a gluten-free diet (GFD). The need for histology of duodenal biopsies to assess mucosal healing after a GFD is still a matter of debate. We evaluated whether tTGs are adequate to detect the persistence of histological lesions of duodenal mucosa in celiac patients after a GFD. Methods: In total 253 patients with histological diagnosis of celiac disease according to Marsh criteria, both at the time of diagnosis (T0) and 18-24 months after starting a GFD (T2), were included. tTGs were evaluated both at T0 and T2; endomysial antibodies (EMAs) only at T0. Results: At T0, 9.2% of patients had both tTG and EMA negative values, despite the evidence of duodenal lesions: 33.3% of Marsh 1, 14.3% of Marsh 2 and 5.2% of Marsh 3. At T2, tTGs were negative in 77.6% of patients: 82.2% of Marsh 0, 79.8% of Marsh 1, 70.0% of Marsh 2 and 59.1% of Marsh 3. At T2, approximately 60% of patients with the persistence of mucosal atrophy had negative tTGs. At T0, tTG median values were lower in patients with Marsh 1 and Marsh 2 than patients with Marsh 3 (P < 0.001), whereas no difference was found at T2 regardless of Marsh's grade (P = 0.4). Conclusions: The results of our study highlight how histologic evaluation of duodenal biopsies remains the gold standard for both celiac disease diagnosis and the evaluation of mucosal recovery after 18-24 months of a GFD.