[Single cell sequencing technology for analyzing the interaction between type 3 innate lymphoid cells and regulatory T cells in patients with fibrostenotic Crohn's disease].

Objective: To investigate the interaction between type 3 innate lymphoid cells (ILC3) and regulatory T cells (Treg) in patients with fibrostenotic Crohn's disease (CD) using single-cell sequencing analysis. Methods: The clinical data of patients diagnosed with fibrostenotic CD were retrospectively collected from the Department of Gastroenterology, the First Affiliated Hospital of Wenzhou Medical University (Wenzhou group) and the Department of Gastroenterology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine (Ruijin group) between January 31, 2023, and June 30, 2024. Fresh intestinal fibrotic tissue samples and non-fibrotic intestinal tissue samples were obtained from each patient for single-cell RibonucleicAcid sequencing (scRNA-seq), differential gene enrichment analysis, etc. Results: The Wenzhou group included 1 patient (male, 29 years old). The Ruijin group included 6 patients [4 males, 2 females, with a median age of 41 (27-52) years]. All cells from the intestinal tissues of both groups were categorized into the following 9 major types: T lymphocytes/innate lymphoid cells (ILC), B lymphocytes, plasma cells, macrophages, epithelial cells, fibroblasts, mast cells, neutrophils, and glial cells. Co-analysis of cell types in the intestinal tissues from both groups revealed that the proportion of ILC3 was lower in fibrotic tissue compared to non-fibrotic tissue (0.71% vs 3.26%, P=0.042). Furthermore, in fibrotic tissues, the expression levels of genes related to antigen presentation, including chemokine motif ligand (CCL)3, CCL4, interferon-γ (IFN-γ), interleukin-2 receptor subunit alpha (IL2RA), regulator of calcineurin 2 (RCAN2), and tumor necrosis factor superfamily member 4 (TNFSF4) were higher in ILC3 compared to non-fibrotic tissues. In the Wenzhou group's intestinal tissues, interactions were observed between ILC3 and Treg, epithelial cells and neutrophils. In the Ruijin group's intestinal tissues, interactions were observed between ILC3 and Treg cells. Conclusion: ILC3 disrupts the intestinal immune microenvironment through interactions with Treg cells, thereby promoting the progression of fibrostenotic CD.