Colonic cell heterogeneity in IBD revealed by single-cell sequencing analysis. Single-cell RNA sequencing reveals subsets of the intestinal epithelium and immune cells according to gene expression patterns. They can be responsible for the maintenance of intestinal epithelium homeostasis, inflammatory responses, and the epithelial barrier, and are present at differential amounts in IBD patients. AQP8, aquaporin 8; BEST4, bestropin 4; CA1, carbonic anhydrase-1; CD, Crohn’s disease; CDCA7, cell division cycle associated 7; CDK6, cyclin-dependent kinase 6; CEACAM7, carcinoembryonic antigen cell adhesion molecule 7; GC-C, guanylate cyclase; HB-EGF, heparin-binding epidermal growth factor-like growth factor; IBD, inflammatory bowel disease; IL-13RA2, interleukin 13 receptor subunit α 2; LGR5, leucine-rich repeat-containing G-protein coupled receptor 5; OTOP2, otopetrin 2; RNMT, RNA guanine-7 methyltransferase; RORγ, Retineic-acid-receptor-related orphan nuclear receptor gamma; SLC20A1, solute carrier family 20 member 1; SLC26A2, solute carrier family 26 member 2; TJ, tight junction; Treg, regulatory T cell; UC, ulcerative colitis; WFDC2, whey-acidic-protein four-disulfide core domain protein 2; WNT5B, Wnt family member 5B.