It has been suggested that in allergic contact eczema IL-18 may act upstream of IL-1ß and TNFα in the induction of Langerhans cell migration [58] and its potential role in allergic contact dermatitis is highlighted by the fact that measurement of IL-18 has been suggested as a tool for the identification of substances with high sensitising potential [51]. This evidence concerns the gene TNF and allergic contact dermatitis.