The antibody called Immunoglobulin E (IgE) may play a crucial role in defending the skin against damage caused by environmental chemicals. It may also have a protective effect against skin cancer (Nature Immunology 2018; 19(8):859–870).
"IgE must have some important role in the body–but at the moment scientists are still unclear what it is. We used to think it protects us against parasites–such as intestinal worms–and the lack of worm infections is causing the allergy rise. However, after previous work suggested the body can still fight parasites without IgE, we do not now believe this to be the only purpose,” said lead author Dr. Jessica Strid, senior lecturer in the Department of Medicine at Imperial College London in London, U.K., in a press release. “Our new work suggests IgE could protect against the damage caused by skin exposure to tumour-promoting chemicals or UV irradiation–and help fight against skin cancer.”
Part of the immune system, IgE can induce allergic reactions by mistakenly recognizing a harmless substance–such as peanuts–as a danger.
Dr. Strid and her colleagues found that placing a toxic chemical on mouse skin activated IgE and caused it to travel to the site of damage. Once there, IgE lowered the risk of cancer development in the skin.
They also studied skin tumours from 12 patients with squamous cell carcinoma.
Photo by Imperial College London.
Results showed that all tumours, some of which were more aggressive than others, had IgE present. Further analysis of a larger cohort of patients showed that less dangerous or ‘low risk’ tumours contained more IgE-carrying cells, while more serious tumours had less. This suggests that IgE may also have a protective effect against the progression of cancer.
“This is just the beginning of the story–our next step is to find out how exactly IgE may stop skin cells turning cancerous, and to see if we can somehow manipulate the allergic response to either protect against, or treat skin cancer,” said Dr. Strid.
Furthermore, the results hint that allergies could be linked to chemicals in the modern environment.
“Our work raises a lot of questions–and we now have to set about answering them. But the initial results support the so-called Toxin Hypothesis, which suggests that chemicals in the environment, such as those in air pollution, arising from industrial combustion and car emissions, as well as from tobacco smoke, could damage the skin and cause a rise in IgE. The theory suggests this rise in IgE may play a role in the alarming increase in allergies over the last decades.”
IgE may have evolved to kick into action when the skin touched something toxic.
“It may be that the IgE would trigger a rash, or a stronger unpleasant response, when the skin contacts something potentially poisonous. This would send a clear message to the body saying this is harmful—do not touch that again,” said Dr. Strid.