6/2/2014 - The OECD has just published two new Test Guidelines on human health hazard endpoint skin sensitisation. Skin sensitisation refers to an allergic response following skin contact with the tested chemical, as defined by the United Nations Globally Harmonized System of Classification and Labelling of Chemicals (UN GHS). Test Guideline 442C concerns an In Chemico procedure for the Direct Peptide Reactivity Assay and addresses the molecular initiating event leading to the skin sensitisation. Test Guideline 442D looks at an in vitro procedure, namely the ARE-Nrf2 luciferase test method, and looks to address the second key event on the adverse outcome pathway leading to skin sensitisation. Both of these Test Guidelines set out the procedures for supporting the discrimination between skin sensitisers and non-sensitisers in accordance with the UN GHS. They are the first two in a series of in vitro methods that will gradually replace in vivo animal Test Guidelines on skin sensitisation; more of these alternative methods are detailed in the work plan of the Test Guidelines Programme<http://www.oecd.org/chemicalsafety/testing/Declassified-TGP-Workplan-28-July-2014.pdf>. · Test No. 442C: In Chemico Skin Sensitisation (Direct Peptide Reactivity Assay (DPRA)<http://www.oecd-ilibrary.org/environment/test-no-442c-in-chemico-skin-sensitisation_9789264229709-en> · Test No. 442D: In Vitro Skin Sensitisation (ARE-Nrf2 Luciferase Test Method)<http://www.oecd-ilibrary.org/environment/test-no-442d-in-vitro-skin-sensitisation_9789264229822-en>