LB758 Decreased presence of Langerhan’s cells and Tregs in biopsies from Bullous pemphigoid patients

Abstract

Assessment of skin sensitization potential has traditionally been conducted in animal models, such as the Mouse Local Lymph Node Assay (LLNA) and the Guinea Pig Maximisation Test (GPMT). However, a growing focus and consensus for minimizing animal use have stimulated the development of in vitro methods to assess skin sensitization. Interleukin-18 (IL-18) release in reconstructed human epidermal models has been identified as a potentially useful endpoint for the identification and classification of skin sensitizing chemicals, including chemicals of low water solubility or stability. The purpose of this study was to investigate the impact of the modality of chemical exposure on the predictive capacity of the assay. EpiDerm tissue viability assessed by MTT assay and IL-18 release assessed by ELISA were evaluated after 24 h topical exposure to test chemicals either impregnated in 8 mm diameter paper filters or directly applied to the surface of EpiDerm. Acetone: olive oil (4:1) was used as vehicle in all cases. A total of five chemicals from 3 different sources were tested. The testing set included 3 senzitizers, namely 2,4-dinitrochlorobenzene, cinnamaldehyde and isoeugenol/eugenol, and 2 non senzitizers, lactic acid and salicylic acid. Four independent dose e response experiments were conducted in 3 laboratories, resulting in correct prediction of the sensitizing potency of test chemicals. The assessment of IL-18 release using in vitro reconstructed normal human epidermal model EpiDerm appears to be a promising tool for in vitro determination of contact sensitization potential.