The clinical course of IBD varies considerably among patients1. One barrier to personalized medicine in IBD is the lack of a reliable prognostic assay that can be used at diagnosis to guide effective therapy for each patient, to optimize clinical outcomes and minimize complications. To address this need, a whole-blood qPCR-based prognostic assay was developed to divide IBD patients into two subgroups2. This transcriptional signature yields CD8 T-cell exhaustion level data that correlated with disease outcomes among IBD patients in UK2.