Plasma IL-25 is elevated in a subgroup of patients with clinical reactivity to peanut

One of the IL-17 family members, IL-25, has been implicated with the initiation and amplification of Th2 responses in animal models and has been associated with airway hyper-reactivity. The involvement of IL-25 and also IL-17 in food allergic disease remains to be investigated. In this study thirty children suspected of peanut allergic disease underwent a double-blind placebo controlled food challenge (DBPCFC) and IL-25 and IL-17 plasma levels were determined before challenge. IL-25 was highly elevated only in subgroup of children with a positive DBPCFC outcome. Plasma IL-25 was absent in children with a negative DBPCFC outcome and in healthy controls. This study shows that IL-25, an IL-17 family member, is highly elevated only in children with a clinical response to peanut. This suggests a role for IL-25 in the pathogenesis of peanut allergy and elevated plasma IL-25 may be a sign of a severe atopic phenotyp