The GARD assay for assessment of chemical skin sensitizers.

Allergic contact dermatitis is a skin disease caused by an immunologic reaction to low molecular weight compounds, so called haptens. These substances are commonly present in products used by humans in daily life, such as in cosmetics and fragrances, as well as within chemical industry and in pharmaceuticals. The frequent usage of these compounds in different applications has led to increasing incidences of allergic contact dermatitis, which has become a substantial economic burden for society. As a consequence, chemicals are routinely tested for their ability to induce skin sensitization, using animal models such as the murine Local Lymph Node Assay. However, recent legislations regulate the use of animal models within chemical testing. Thus, there is an urgent need for in vitro alternatives to replace these assays for safety assessment of chemicals. Recently, we identified a signature of predictive genes, which are differentially regulated in the human myeloid cell-line MUTZ-3 when stimulated with sensitizing compounds compared to non-sensitizing compounds. Based on these findings, we have formulated a test strategy for assessment of sensitizing compounds, called Genomic Allergen Rapid Detection, GARD. In this paper, we present a detailed method description of how the assay should be performed.