DOP89 Pre-treatment mucosal inflammatory and wound healing gene programmes reveal mechanisms associated with future stricturing behaviour during 5-year follow-up in paediatric Crohn’s disease

Abstract Background Stricturing complications account for substantial morbidity in Crohn’s disease (CD). We aimed to define ileal gene programmes present at diagnosis in paediatric CD associated with future stricturing behaviour (B2), and to identify potential small molecules to reverse these gene signatures. Methods Antimicrobial serologies and ileal gene expression (RNASeq) were assessed at diagnosis in 249 CD patients enrolled in a 5-year inception cohort study. These data were used to define genes associated with stricturing behaviour and for model testing to predict stricturing. Sirius Red immuno-histochemistry was utilised to determine the extent of collagen infiltration into the sub-cryptal space. A bioinformatics approach defined small molecules which may reverse the stricturing gene signature. Results Of 249 (8%) patients, 19 developed B2 behaviour during the 5-year follow-up, while 218 remained B1 inflammatory. We defined 518 genes that were differentially expressed in the ileum at diagnosis (FC≥1.5, FDR