Despite strict adherence to gluten free diet (GFD), the complete healing of the duodenal mucosa of celiac patients is rarely achieved. The cause of the persistence of the inflammation is not yet understood.~It is well known that there is a high degree of variability in individual response to gluten with some patients worsening of duodenal histology upon exposure to very small amount of gluten.~This observation suggest that contamination with gluten of commercially available processed food and/or small amount of gluten in processed foods labeled gluten-free (less than 20 ppm) may prevent complete mucosal healing.~This explanation is indirectly supported by a study of Hollon et al. (2013) showing that persistence of gastrointestinal symptoms in celiac patients on a GFD is abolished, in 85% of cases, by the adoption of a diet based exclusively on naturally gluten-free products, and on the elimination from the diet of commercially available processed food and products labeled gluten free  (Gluten Contamination Elimination Diet, GCED).~The main aim of this study was to assess whether the complete healing of duodenal mucosa in patients with persistent Mars I-II lesions after 1 year on GFD i) could be achieved, as a proof of the concept, by the adoption of a GCED OR ii) may depend upon time of exposure to GFD. To achieve this aim investigators studied 2 cohorts of patients with Marsh I-II lesion after 1 year on GFD: cohort A re-byopsied after 3 month GCED , and cohort B re-biopsied after a minimum of further 2 years on standard GFD.
The study assessed whether compete healing of duodenal mucosa in celiac patients with persistent Marsh I-II lesion after 1 year of gluten free diet (GFD):~could be achieved by adoption of a diet based exclusively on naturally gluten free products, with the elimination of commercially available processed food (GCED, Gluten Contamination Elimination Diet);~may depend upon time of exposure to GFD.~Investigators studied two cohorts of celiac patients, both on GFD, for at least one year:~cohort A: patients re-biopsied after three months on GCED;~cohort B: patients re-biopsied after a minimum of further two years on standard GFD.