A rapid in vitro method of identifying contact allergens and irritants

A rapid in vitro method has been developed to screen skin allergens and irritants. It has been shown by others that allergens induce the secretion of interleukin (IL)-1beta by dendritic cells and macrophages, which are known antigen-presenting cells present in blood, and that irritants induce the secretion of IL-1alpha by the same cells. We have shown that the allergens nickel, chromium, isoeugenol, and dinitrofluoro benzene induce the secretion of IL-1beta at levels that are two-to threefold higher than those of controls and that the nonallergens and irritants sodium dodecyl sulfate, Tween-20, acetic acid, sodium hydroxide, and dimethyl sulfoxide fail to induce such a response. All the chemical allergens tested induced the secretion of IL-1alpha at concentrations two- to fivefold higher than those of controls, depending on the concentration and the particular irritant. Allergen-induced T-cell proliferation has also been demonstrated by the expression of IL-2 as well as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolim bromide reduction (MTT) assay (10-50% more than control). All the allergens and irritants caused cytotoxicity at higher doses, as indicated by the release of lactate dehydrogenase. This method can be used to differentiate the allergens from the irritants in a simple and convenient manner.