Relationship between serum levels of interleukin-18, IgE and disease severity in patients with atopic dermatitis.

ABSTRACT

BACKGROUND: Interleukin (IL)-18 is a pleiotropic cytokine. Synergistically with IL-12, IL-18 promotes immune responses of the T helper type, by enhancing synthesis of interferon-γ and inhibiting IgE production. IL-18 can also enhance production of IL-4 and IL-13 production, and stimulate synthesis of IgE. Moreover, in the presence of IL-3, IL-18 can directly stimulate basophils and mast cells to produce their mediators in an IgE-independent manner. These results indicate a role for IL-18 in the pathogenesis of atopic dermatitis (AD). AIM: To examine the association of serum IL-18 with IgE levels and disease severity in patients with AD. METHODS: ELISA was used to measure IL-18 and total IgE levels in the sera of 67 patients with AD and 50 healthy volunteers. The SCORing Atopic Dermatitis (SCORAD) tool was used to determine the severity of this disease. RESULTS: The mean serum level of IL-18 in study group (155.68 pg/mL) was significantly higher than that of controls. IL-18 was also significantly higher in the sera of the patients with severe AD than in those with milder disease. There was a correlation with IgE and IL-18 levels, as patients who had high IgE levels also had high IL-18 levels, compared with controls. CONCLUSION: IL-18 seems to play an important role in the pathogenesis of AD, but this requires further study. IL-18 could be a useful clinical marker of disease severity in AD.