Mild Duodenal Mucosal Injury and Increased Type I Interferon Signaling Are Preludes to Celiac Disease.

Celiac disease (CeD) is an immune-mediated chronic enteropathy caused by gluten exposure in genetically susceptible individuals. The characteristic histologic features of CeD include increased intraepithelial lymphocytes and villous atrophy. Clinically, a subset of individuals with elevated concentrations of serum tissue transglutaminase (TTG) antibodies have intact duodenal villous architecture at initial endoscopy and biopsy but then progress to CeD over time while on gluten-containing foods. We hypothesized that these rare potential CeD cases with progression can allow us to interrogate histologic and molecular signatures to predict those who subsequently develop CeD and to study the final cascade into the overt lesions of CeD. We retrospectively identified 16 children over a 10-year period with elevated serum TTG antibody concentrations but without significant villous atrophy at index duodenal biopsies, in whom subsequent biopsies confirmed CeD while consuming gluten-containing foods. Their clinical and histologic features were compared with age-, race-, and gender-matched controls including active CeD (n = 28) and non-CeD children (negative TTG antibody, normal histology, n = 35). Transcriptomic analysis was performed on a subset of the index biopsies of potential CeD cases with progression and controls. None of the 16 children with potential CeD with progression had a family history of CeD or presented with poor growth or anemia or had commenced a gluten-free diet at the time of index biopsy. The index biopsies of children with potential CeD with progression had significantly greater prevalence of intraepithelial lymphocytes (81% vs 12%, P = .002) and mild villous atrophy (94% vs 22%, P = .006) compared with non-CeD biopsies; none had severe villous atrophy (P = .002). Transcriptomic analysis demonstrated upregulated type I interferon signaling, Janus kinase (JAK)/signal transducer and activator (STAT) pathway of transcription activation and innate and adaptive immunity in duodenum of potential CeD with progression was comparable to non-CeD but preserved signaling in brush border absorption, transporter functions, and epithelial metabolic functions, compared with active CeD. Our results show for the first time that mild mucosal injury in the duodenum of children with potential CeD with progression is accompanied by upregulation of pathways also activated in CeD. Mild mucosal injury and type I interferon signaling may be the initiating cellular and molecular biomarkers in identifying the subset of potential CeD individuals who would progress to CeD while consuming gluten-containing foods.