REPOGRAMING OF THE INTESTINAL IMMUNE CELL COMPARTMENT DEFINES THE RESPONSE TO AUTOLOGOUS STEM CELL TRANSPLANTATION IN CROHNS DISEASE

Abstract INTRODUCTION For the treatment of refractory Crohn’s disease (CD) autologous stem cell transplant (auto-SCT) is unparalleled in its ability to induce clinical and endoscopic remission.(1, 2) Auto-SCT is unique as a cellular therapy aimed to reset immune pathophysiology to a pre-disease state using hematopoietic stem cells. As such, the study of how the immune system responds to auto-SCT will provide unique insight into CD pathogenesis and treatment. To date, no studies in any cohort have defined the mucosal and peripheral immune response to auto-SCT. Here we report initial studies of high dimensional immune phenotyping of patients with CD during auto-SCT. METHODS Patients with CD were enrolled in a Phase IIa study of auto-SCT (NCT03219359). 14 patients were transplanted (2018-2022). Paired blood and intestinal samples were taken prior to transplant and 6 months post-transplant. Fresh leukocytes were isolated and analyzed by mass cytometry (CyTOF). Supervised clustering of immune cell populations using canonical markers was performed in parallel with unsupervised clustering by FlowSOM.(3) RESULTS After 6 months post-transplant,12/13 patients had an endoscopic response (↓SES-CD by 50%) and 10/13 patients were in endoscopic remission (SES-CD