Inflammatory bowel disease (IBD) is an immune-mediated disorder that is associated with chronic, relapsing, and remitting inflammation of the gastrointestinal tract. It can occur in two forms—ulcerative colitis (UC) and Crohn’s disease (CD)—that have overlapping mechanisms of pathogenesis but distinct patterns of histology, regional distribution, and clinical features. Like other diseases linked to dysfunction of the immune system, IBD has been increasing in incidence and prevalence over the last several decades and is estimated to affect close to 1.5 million individuals in the United States (Cosnes et al., 2011; Molodecky et al., 2012). It is currently one of the leading chronic gastrointestinal diseases and represents a significant economic and quality of life burden, with direct healthcare costs of $10,000–$20,000 per year per patient (Cohen et al., 2010; Floyd et al., 2015). The magnitude and chronicity of the problem, as well as the shortcomings of the treatment options that are currently available, are motivating factors in the ongoing search for improvements in IBD therapy.