Impact of a Low-FODMAP Gluten-free Diet on Gut Microbiota and Circulating miRNAs in Celiac Disease Patients

15 patients with refractory celiac disease (RCD) and 15 patients with CD responsive to the GFD between the ages of 21 and 60 will be enrolled. The aim of the research will be: 1) to characterize the intestinal, blood and duodenal microbiota, then to evaluate both the taxonomy of the identified bacteria and their relative abundance 2) to analyse the profile of miRNAs from biopsy and fibroblasts isolated in the first duodenal portion, highlighting any basal deregulation and, for fibroblasts, after treatment with the 33-mer immunogenic peptide 3) quantify and know the composition of the fecal microbiota in celiac patients with persistent symptoms and in refractory celiac patients before (T0) and after (T28) treatment with a low-FODMAP diet. The aim of the study is to observe a diversification of the microbiota pattern of refractory patients vs. normoresponsive celiac patients and to observe a deregulation in the expression of miRNAs, both basally on biopsies and after treatment with the immunogenic peptide in primary fibroblast cultures.