IL37 and inflammatory bowel disease: Very early-onset inflammatory bowel disease (VEO-IBD) accounts for 1% to 15% of childhood inflammatory bowel disease (IBD) cases and is often refractory to medical therapy.1,2 Ustekinumab (UST), a human monoclonal antibody directed against P40, a subunit of interleukin-12 and interleukin-23, is approved for treatment of refractory ulcerative colitis (UC) and Crohn’s disease (CD).