Evaluation of SensCeeTox® an Integrative Model for Identifying Chemical Sensitizers

Allergic contact dermatitis is the result of an adaptive immune response of the skin after direct exposure to an allergen (Figure 1). Because it is themost common manifestation of immunotoxicity in humans, a strict screening of all ingredients in consumer products is required. Current methods fordetermining chemical sensitization rely on animal testing (e.g. local lymph node assay). However, ethical concerns and regulatory changes inthe EU have triggered the development of alternative tests for the assessment of potential sensitizers. Several developed but there is a common view that a strategy for the integration of the available methods will be required. In that perspective Ceetox Inc.has developed an integrative approach, namely SensCeeToxto differentiate between non-sensitizer (NS), weak (W), moderate (M), strong (St), and extreme (E), sensitizer (S). The purpose of this study was toevaluate the predictive capacity of this approach in a blinded manner. L’Oréal provided a set of 40 compounds (20 positive and 20 negative),in vitro predictive assays have been® . The method may provide a means to predict potency categories and thereforeconsisting of 24 proprietary and 16 public domain chemicals that were assessed by CeeTox. All 40 compounds could be classified; those placed intoE, St, and M were considered positive (S), while compounds classified as W or N were considered negative (NS). Accuracy was 72%, with a sensitivityof 71% and a specificity of 74%. However, the model failed to accurately predict each sensitization category. Refinements and automation of thealgorithm and the incorporation of additional assays should improve the models’ ability to predict potency.