Systemic reprogramming of monocytes in Crohn’s disease promotes their intestinal inflammatory function

Dysfunctional intestinal monocyte-derived macrophages contribute to pathology in Inflammatory Bowel Disease (IBD). Signals from the tissue micro-environment contribute to this dysfunction, however growing evidence suggests that monocytes can be primed for inflammatory function prior to tissue recruitment. Here we use single cell RNA sequencing (scRNA-seq) to define blood monocyte heterogeneity in a cohort of newly diagnosed, treatment naive Crohn’s disease and Ulcerative Colitis patients and healthy controls, and to establish the scope of of IBD-associated transcriptional changes in monocyte populations prior to arrival in the intestine.