Crohn’s disease and ulcerative colitis are part of the group called inflammatory bowel disease (IBD), a medical condition where the immune system is causing severe intestinal and colonic inflammation leading to severe complications. Former therapies rely on suppressing the immune system but modern treatments, so-called biological treatments, are blocking certain steps in disease progression or activation. Those specific therapies need to be given to each patient in a precise way to optimize the treatments and thus, avoiding non-responders or predicting complications before starting the treatment is paramount. Here we plan to develop a new assay to personalize each patient’s treatment by measuring all characteristics, so-called bio markers, of the individual patient at once by a modern technology called CyTOF and MIBI. Up to a hundred of those tests can be investigated simultaneously and thus, the physician can choose the optimal drug and better understand each patient’s disease.