IL-1 alpha and IL-1ra secretion from epidermal equivalents and the prediction of the irritation potential of mild soap and surfactant-based consumer products

We have previously evaluated the measurement of viability and cytokine rele ase from skin equivalents, for predicting the skin irritation potential of topically applied surfactants and demonstrated that IL-1 alpha and interleu kin-1 receptor antagonist (IL-1ra) release from epidermal skin equivalents correlates with skin irritation potential. In this study, the utility of th e model was confirmed by the evaluation of cleansing bars and cleansing lot ions that exhibited varying degrees of irritation potential as determined b y exaggerated arm wash human clinical studies. Epidermal equivalents were e xposed to increasing concentrations of the cleansing bars and cleansing liq uids and Viability and release of IL-1 alpha and IL-1ra were measured. Loss of viability was used to identify the stronger irritants of the products t ested. A linear correlation was demonstrated between IL-1 alpha and IL-1ra secretion and human irritation data, demonstrating that the model can corre ctly predict the irritation potential of soap and surfactant products. Thes e results show that this in vitro model is useful for rank ordering the irr itation potential of mild consumer products and for demonstrating enhanced mildness in products with minor differences. (C) 1999 Elsevier Science Ltd. All rights reserved.