When 34-year-old Amina Rahman had her ileum biopsied at Addenbrooke’s Hospital in Cambridge, she became part of a groundbreaking effort that would map the inner life of Crohn’s disease at an unprecedented resolution. Her cells, along with those of 110 other patients and 232 healthy volunteers, were analyzed by researchers from the Wellcome Sanger Institute and Cambridge University Hospitals NHS Foundation Trust, creating the most detailed atlas yet of how this debilitating condition rewires the gut at the cellular level. By sequencing more than 1 million individual cells, the team uncovered how gene activity shifts across over 50 distinct gut cell types—revealing not just the drivers of inflammation, but also lasting molecular imprints even after symptoms subside.
Crohn’s disease, which affects over half a million people in the UK alone, has long baffled scientists and clinicians alike. While it’s known to involve an overactive immune response in genetically susceptible individuals, the precise cellular players and their interactions have remained murky. This lack of clarity contributes to the fact that 15% of patients still require surgery within five years of diagnosis, despite existing therapies. The new study, published in Nature Genetics, cuts through that complexity by pinpointing specific immune cells and genetic pathways involved in disease progression—offering hope for more targeted, effective treatments.
One of the most striking discoveries was what the researchers call a 'molecular scar' in the gut lining. Even in patients whose inflammation had visibly healed, gut stem cells continued to express genes that signal to the immune system—suggesting that past flare-ups leave a lasting biological memory. This could explain why the gut remains hypersensitive in Crohn’s patients, primed to overreact to future triggers. The team also identified a distinct population of macrophages with high expression of the gene ITGA4, which drive inflammation through the JAK/STAT signaling pathway. Crucially, this pathway is already targeted by existing drugs—JAK inhibitors—used in IBD treatment, reinforcing the clinical relevance of the finding.
All of this data is now publicly available through IBDverse, an open-access resource housing molecular profiles from more than 1.18 million cells isolated from the small intestine. Built from samples collected at CUH and analyzed in collaboration with Open Targets, IBDverse is already being used by researchers worldwide to explore new drug targets and disease mechanisms. By mapping gene expression at single-cell resolution, the study not only deepens our understanding of Crohn’s but also sets a new standard for how complex diseases can be studied.
As Amina puts it, 'Knowing my cells might help others avoid the surgeries and setbacks I’ve had—that makes the biopsy worth it.' With this atlas now in hand, scientists are better equipped than ever to turn the tide against Crohn’s—one cell at a time.