Adjuvant effect of plasticizers

National Institute of Occupational Health, Department of Chemical Working Environment, Copenhagen, Denmark 

The immune system constitutes an impoitant taiget for anthropogenically introduced pollutants, i.e. the so-called xenobiotics. The interactions between the immune system and xenobiotics may alter the immune system giving rise to the development of diseases, including allergy. Diesel exhaust particles, DEPs, constitute the best known example of a xenobiotic, which have been shown to promote airway allergies such as asthma and rhinitis (hay fever).Substances with this type of effect are called adjuvants. Other examples of xenobiotics with adjuvant effect include certain anionic, non-ionic, and cationic detergents. 

Recently, the most important phthalate plasticizers have been investigated for adjuvant effect. The first investigation, indicating a possible interplay between phthalate plasticizers and airway allergy, was an epidemiological study published in 1997. This study hypothesized that the plasticizer di-(2-ethylhexyl) phthalate, DEHP, in PVC materials promoted development of asthma in children. However, it was not possible to show definitively that DEHP is an adjuvant. To elucidate whether phthalate plasticizers actually possess adjuvant effect, series of phthalates and their monophthalate metabolites were studied in an animal model. These studies are the only controlled studies, which allow scientific insight in adjuvant effect of phthalate plasticizers and the results are summarized in the present chapter. 

Allergy in the respiratory tract may be defined as an overreaction of the immune system to inhaled, virtually harmless substances. Airway allergies, including rhinitis (hay fever) and allergic asthma, are commonly caused by proteins from house dust mites, cockroaches. 

Health and Safety Issues with Plasticizers and Plasticized Materials 

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