TNF and Crohn disease: Fistulising disease complicates Crohn’s disease (CD) in up to 40% of patients.1–3 Fistulas rarely heal spontaneously and usually require medical therapy or surgery.1 Antibiotics and immunosuppressive agents have been widely used for treatment, although their efficacy for the sustained closure of fistulas has not been proved.1 Tumour necrosis factor (TNF) antagonists specifically target the elevated concentrations of TNF that contribute to the pathological inflammation in CD and represent a significant therapeutic advance in the treatment of patients with CD.