Gluten induces rapid reprogramming of natural memory αβ and γδ intraepithelial T cells to induce cytotoxicity in celiac disease

Celiac disease (CD) is an autoimmune disease in which intestinal inflammation is induced by dietary gluten. The means through which gluten-specific CD4+T cell activation culminates in intraepithelial T cell (T-IEL)–mediated intestinal damage remain unclear. Here, we performed multiplexed single-cell analysis of intestinal and gluten-induced peripheral blood T cells from patients in different CD states and healthy controls. Untreated, active, and potential CD were associated with an enrichment of activated intestinal T cell populations, including CD4+follicular T helper (TFH) cells, regulatory T cells (Tregs), and natural CD8+αβ and γδ T-IELs. Natural CD8+αβ and γδ T-IELs expressing activating natural killer cell receptors (NKRs) exhibited a distinct TCR repertoire in CD and persisted in patients on a gluten-free diet without intestinal inflammation. Our data further show that NKR-expressing cytotoxic cells, which appear to mediate intestinal damage in CD, arise from a distinct NKR-expressing memory population of T-IELs. After gluten ingestion, both αβ and γδ T cell clones from this memory population of T-IELs circulated systemically along with gluten-specific CD4+T cells and assumed a cytotoxic and activating NKR-expressing phenotype. Collectively, these findings suggest that cytotoxic T cells in CD are rapidly mobilized in parallel with gluten-specific CD4+T cells after gluten ingestion. scRNA-seq and scTCR-seq were performed on intestinal biopsies from 11 patients with newly diagnosed or active CD (ACD), 19 celiac patients treated with a GFD, 7 patients with PCD, and 17 healthy controls. scRNA-seq and scTCR-seq were also performed on sorted CD38+CD103+B7integrin+ CD8+ and γδ T cells isolated from the peripheral blood of 5 celiac patients who underwent oral gluten challenge. CITE-seq was also performed on T cells from patients ACD 1-10, GFD 1-14, PCD 1-2, CONTROL 1-16, and GC 1-3.