A team of scientists, led by the
Institute of Food Research (IFR) in the UK, has discovered an immune system malfunction that is likely to play a profound role in food allergy.
Food allergy can be life threatening, but understanding the cause has remained a challenge for science. The international team has found that two types of cells stop communicating. “Either they are not listening to each other or they stop talking”, said research leader Dr Claudio Nicoletti of the IFR. This means that the programmed cell death of one type of cell fails to happen. Programmed cell death is one of the most important mechanisms for maintaining health in mammals.
“There are two stages to food allergy”, said Dr Nicoletti. “The first is sensitisation, when the immune system starts producing an antibody in response to eating a food. The second is when that food is eaten for a second time, triggering an allergic reaction. We have identified an immune response malfunction that occurs in the sensitisation stage, which could provide a target for future therapies”, he said.
There is no current cure for food allergy and vigilance by an allergic individual is the only way to prevent a reaction. In allergic reactions the body overproduces the antibody IgE causing many symptoms including skin rashes, wheezing, sneezing, swelling around the lips, bloating, vomiting and diarrhoea. In extreme cases it causes anaphylaxis, a life-threatening reaction triggered within minutes.
Two critical cells types for regulating immune response are dendritic cells and T-cells. Dendritic cells are white blood cells with fine branches called dendrites. They are stationed at parts of the body most likely to come into contact with pathogens, particularly the skin and mucous membranes. They capture a section of any foreign body, deliver it to other immune cells such as T-cells and instruct these cells to deal with the intruder.
A class of T-cells called T helper 2 cells (Th2) was thought to play an important role in sensitisation to harmless substances including food. But research by IFR scientists questioned this assumption*, so they shifted focus for the current study.