High concentrations of IL‐38 have been observed in patients with asthma, chronic hepatitis B, rheumatic arthritis and Crohn's disease, and its expression is associated with the severity of these diseases.34, 35, 36, 37, 38, 39, 40, 41, 42 IL‐38 production is elevated in clinical sepsis and negatively associated with the number of blood leucocytes and expression of inflammatory cytokines.43 Moreover, rmIL‐38 administration can modulate inflammatory response and facilitate bacterial clearance. Here, IL1F10 is linked to Crohn disease.