TNF and irritable bowel syndrome: This approach has facilitated the characterization of temporal variation in IBD.19,61,62,153,154 It has identified signals associated with response to anti-TNF therapy,19 as well as the likelihood of successful clinical and histological remission of UC after FMT.62 However, this approach also limits our ability to uncover subject-specific characteristics of the disease or the likelihood a specific patient will respond to treatment, one of the premises of personalized medicine.