Very Early-Onset IBD-Associated IL-18opathy Treated with an Anti-IL-18 Antibody

<b>Background/Objectives</b>: The aetiology of inflammatory bowel disease (IBD), particularly if occurring early in childhood, is a diverse and patient-focused treatment that is required when standard therapy is ineffective. <b>Materials and Methods:</b> A clinical case report is presented of a child with very early-onset IBD (VEOIBD) and evidence of high serum IL-18 responding to anti-IL-18 immunotherapy. Detailed cytokine profiling was performed by ELISA and multiplex assay flow cytometry. <b>Results:</b> A four-year-old girl with recalcitrant VEOIBD from six weeks old due to an IL-18opathy, characterised by high blood IL-18 concentration, responded to therapy with a novel neutralising anti-IL-18 antibody (GSK1070806). After two years of hospitalisation, the child's systemic inflammation and extensive upper and lower gastrointestinal mucosal ulceration remitted with this cytokine inhibitor, allowing the discontinuation of total parenteral nutrition and the resumption of normal oral intake and daily activities. After 18 months on regular GSK1070806, the patient remains in disease remission. <b>Conclusions:</b> VEOIBD can be associated with evidence of an underlying IL18opathy and responds to anti-IL-18 antibody therapy. IL-18 should be measured in patients with IBD unresponsive to conventional treatments, and, if elevated, anti-IL-18 antibody therapy should be considered as a potential therapy.