Itchy, red rashes appear on the skin when allergic reactions occur, like poison ivy. This includes personal care goods such as cosmetics and skin lotion that frequently cause rashes. These rashes, known as allergic contact dermatitis, are caused by chemical components found in personal care products.
A foreign substance, known as an antigen, is detected by immune system cells known as T cells, which attempt to neutralize it. Allergy reactions can be triggered by T lymphocytes identifying portions of proteins or peptides. Compounds in personal care products have previously been undetectable by T cells. Initially, they were thought to be too tiny and lacked the required chemical groups.
According to a study by researchers, personal care items may include chemical components that can elicit a T-cell response. Annemieke de Jong, D. Branch Moody of Brigham and Women’s Hospital and Harvard Medical School, and Jamie Rossjohn of Monash University and Cardiff University School of Medicine led the research team.
The researchers hypothesized that an immune cell surface protein called CD1a, situated on the skin’s outer layer, was likely to have a role in explaining how personal care items can provoke contact dermatitis. They exposed human cells in tissue culture to probable allergens in personal care items to examine the molecule’s significance. Allergists employ skin patch testing kits for this purpose. Immediately after cutting the allergen patches, they were inserted straight into wells of T cells. After that, they looked at how much T cell activation had occurred.
Balsam of Peru, a tree oil commonly used in cosmetics and toothpaste, was discovered to provoke an immunological reaction by the research team. The compounds benzyl benzoate and benzyl cinnamate were responsible for activating the T cell response in Peruvian balsam.
The researchers discovered that the molecule farnesol, commonly used in personal care items as a fragrance, was also found to cause an allergic reaction. CD1a binds to farnesol to trigger an immunological response through X-ray crystallography, according to researchers.
Farnesol displaces the bigger lipid molecules normally found in CD1a’s tunnel-like interior with its own smaller lipid molecules. The CD1a protein contains lipids that protrude from its surface. In the absence of these proteins, immune cells cannot connect with typically inactive portions of the molecule.
It has been shown that common compounds in personal care products can directly activate T cells. The next step is to conduct a clinical trial to determine if these T cells induce allergic contact dermatitis in patients.
“We have a missing molecular link,” explains Moody. T cells responding to proteins or peptide antigens are thought to be the only trigger for an allergic reaction, but our findings challenge that conventional wisdom.” A protein called CD1a has been identified as a trigger for a T cell response in the presence of scent.”