Distal Duodenum Versus Duodenal Bulb: Intraepithelial Lymphocytes Have Something to Say in Celiac Disease Diagnosis

Background and Aim After clinical screening and the serological test, many patients still require a duodenal biopsy for celiac disease diagnosis. Mild histological lesions, unspecific findings and patchiness are frequent outcomes of this mandatory diagnostic tool, thus complicating clinical decisions. Methods We analyzed the lymphoid components [number of total intraepithelial lymphocytes (IELs), TcR-gamma delta and CD3(-)IELs] of the duodenal epithelium by flow cytometry in samples obtained from bulb and distal duodenum during upper gastrointestinal endoscopies performed for diagnostic purposes. Results IEL counts and IEL subset distribution (IEL lymphogram) remain invariant along duodenal mucosa revealing a specific profile (immunophenotype) that characterizes either a healthy mucosa or a celiac mucosa. The celiac immunophenotype persists regardless of the biopsy's anatomical location or the corresponding histological findings. Conclusions We propose the IEL lymphogram by flow cytometry as an immunological parameter to discern celiac condition from healthy mucosa. This obviates not only misinterpretation of minor histological changes, but also patchiness and the concerns about the location and number of biopsies.