A single-cell based study from Prof Alison Simmons Lab recently, in which clonic epithelial cell diversity was profiled in health and inflammatory bowel disease (IBD). Breakdown of the epithelial barrier underpins inflammatory bowel disease (IBD), and the authors show that WFDC2 preserves the integrity of tight junctions between epithelial cells and prevents invasion by commensal bacteria and mucosal inflammation. Roman Fischer and Benedikt Kessler from the TDI participated in this study.