An expanding range of therapeutics have been approved or are under development for IBD. However, objective readouts of treatment efficacy are still lacking, often relying on partially subjective clinical endpoints (CDAI). High-dimensional mass cytometry (CyTOF) combines flow cytometry with elemental mass spectrometry, allowing the simultaneous quantification of up to 40 surface and/or intracellular markers on a single cell basis. This technique presents a novel tool by which the therapeutic effects of drugs could be examined directly within the target tissue.