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Immune effects of respiratory exposure to fragrance chemicals

Immuuneffecten van respiratoire blootstelling aan geurstoffen


Inhalation of the fragrance chemicals, isoeugenol and cinnamal, by mice resulted in immune reactions in the respiratory tract. This was observed in experiments performed by the RIVM (National Institute for Public Health and the Enviroment) of which results indicate that inhalation of some fragrance chemicals could induce unwanted effects on the immune system. Fragrance chemicals are common ingredients in such consumer products as cosmetics and scented products. Several fragrance chemicals are known to cause allergy after skin exposure, but it is unknown whether inhalation of these fragrance chemicals can cause allergic reactions or other unwanted immune reactions. Till recently, it was assumed that inhalation of fragrance chemicals was harmless for humans, because there was no exposure via inhalation. However, applying fragrance chemicals in scented products used indoors, has changed this. RIVM investigated the effects of inhalation of isoeugenol and cinnamal, fragrance chemicals that can cause skin allergy. Mice were exposed to the fragrance chemicals via inhalation. Effects on the immune system were measured using a respiratory lymph node assay, which measures cell proliferation in lymph nodes of the respiratory tract. Inhalation of both isoeugenol and cinnamal resulted in stimulation of the immune system of the respiratory tract. The effects of isoeugenol were more pronounced than those of cinnamal. This is in contrast with results observed after skin exposure, after which both these fragrance chemicals were found equally potent in inducing skin allergy. This implies that effects of fragrance chemicals on the immune system depend on the route of exposure. Relevant routes of exposure should then be used to predict the hazard of inhaling these compounds: skin for cosmetics and the respiratory tract for scented products. To obtain more insight into the hazards of fragrance chemicals used in scented products, RIVM is advising assessment of more fragrance chemicals in the respiratory lymph node assay.

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