The Center for Alternatives to Animal Testing is an academic center affiliated with the Division of Toxicological Sciences in the Department of Environmental Health Sciences of the Johns Hopkins University Bloomberg School of Public Health.

 

Johns Hopkins School of Public Health

Research Grants 1998-1999

Validation of a Human Quantitative Structure-Activity Relationship (QSAR) Model for Acute Contact Dermatitis

Jurij J. Hostynek, PhD
Euroamerican Technology Resources, Inc., Lafayette, California

Allergic contact dermatitis (ACD), a form of inflammation of the skin, is a public health problem caused by natural or man-made chemicals, encountered in everyday life. Particularly in the workplace contact with certain chemicals can cause incapacitating conditions described as hypersensitivity reactions, which can make necessary lengthy interruptions in customary professional or trade activities, or even lead to permanent disability.

At the present no mathematical model is available for the prediction of skin sensitization potential of chemicals. For all newly synthesized compounds, regardless of their ultimate intended use, predictive testing in laboratory animals is an ethical and legal requirement prior to widespread human exposure, one also mandated by law.

In Phase I of the current project a biologically based, statistical model is in development which is predictive of such hypersensitivity potential. The mathematical equation allows the recognition of allergenic compounds and distinguishes them from non-allergens in humans. It identifies those chemicals which, on skin contact, will cause delayed-type allergic reactions of the poison ivy and poison oak type.

In order to test validity and robustness of the model, in Phase II the QSAR model will be validated by submitting a new set of chemicals suspected of allergenic potential to analysis. A successful model will greatly reduce the number of laboratory animals needed for allergy testing, thanks to easy identification of sensitization risk. The model also may serve as an early alert in chemical product development, curtailing unnecessary testing in animals.