Interleukin-18 is associated with increased severity of atopic dermatitis in children.

Atopic dermatitis (AD) is a chronic relapsing skin disease characterized by reduced interferon (IFN) gamma production with concurrent up-regulation of interleukin (IL)-4. Recently, it was reported that IL-18, formerly called IFN gamma-inducing factor, induces the production of T helper (Th)2-related cytokines without help from IL-12. This study was performed to evaluate the contribution of IL-18 in the pathogenesis of AD. Significantly higher serum IL-18 concentrations were found in patients with severe AD than in healthy subjects. Under staphylococcal enterotoxin B stimulation, IL-18 secretion was increased in peripheral blood mononuclear cells from patients with AD. There were significant differences in the concentrations of IL-10, IL-12, and soluble Fas ligand between AD patients and normal controls. In conclusion, increased serum IL-18 concentrations may be involved in the pathogenesis of AD.