Characterization of T Cell Receptor Repertoires In Celiac Disease

Abstract

Aims: Characterize T-cell receptor gene (TR) repertoires of small intestinal T cells of patients with newly diagnosed (active) celiac disease (ACD), refractory celiac disease type I (RCD I) and CD patients on a gluten-free diet (GFD).Methods: Next-generation sequencing of complementarity-determining region 3 (CDR3) of rearranged T cell receptor beta (TRB) and gamma (TRG) genes was performed using DNA extracted from intraepithelial cell (IEC) and lamina propria cell (LPC) fractions and a small subset of peripheral blood mononuclear cell (PBMC) samples obtained from CD and non-CD (control) patients. Several parameters were assessed, including relative abundance and enrichment.Results: TRB and TRG repertoires in CD tissue samples demonstrated lower clonality but higher frequency of rearranged TRs compared to controls. No CD-related differences were detected in the limited number of PBMC samples. Previously published LP gliadin-specific TRB sequences were more frequently detected in LPC samples from CD patients compared to non-CD controls. TRG repertoires of IECs from both ACD and GFD patients demonstrated increased abundance of certain amino acid (AA) motifs compared to controls, encoded by multiple nucleotide variants, including one motif that was enriched in duodenal IECs versus the blood of CD patients.Conclusions: Small intestinal TRB and TRG repertoires of CD patients are more diverse than individuals without CD, likely due to mucosal recruitment and accumulation of T cells because of protracted inflammation. Enrichment of the unique TRG CDR3 AA sequence in the mucosa of CD patients may suggest disease-associated changes in the TCRGD IE lymphocyte (IEL) landscape.