A NOVEL treatment option for allergic contact dermatitis has been suggested in a new study which looked at how lipids in the skin are replaced by chemicals found in nonprescriptional topical products. The ingredients in these products can produce a rash similar to one that would be triggered by poison ivy.
In order for small chemicals to be recognised by T cells, they need to react with large proteins. Small compounds in skincare products do not have the chemical groups for this reaction, however they are still visible to T cells. The authors, co-led by Dr Annemieke de Jong, from Columbia University Vagelos College of Physicians and Surgeons, New York City, New York, USA, suggested that CD1a, a molecule abundant in Langerhans cells, may be responsible for granting the small chemicals recognition. The study showed several chemicals known to trigger contact allergic dermatitis were able to bind CD1a molecules and activate T cells. The researchers identified numerous small chemicals which can be found in personal skincare products capable of activating T cells via CD1a. “Our work shows how these chemicals can activate T cells in tissue culture, but we have to be cautious about claiming that this is definitively how it works in allergic patients,” Dr de Jong commented.
CD1a molecules are prevented from reacting with T cells by binding naturally occurring lipids on the inner layers of the skin. Allergens from skincare products can displace the lipid bound with the CD1a molecule, making the compound visible to T cells and triggering an immune reaction. The study raised ideas that the application of competing lipids could displace allergens and prevent the immune reaction and lipids with the ability to bind without activation of T cells have been identified in previous studies.