Understanding allergic symptoms and ige
Celebrating the 50 year anniversary of the discovery of Immunoglobulin E
Most people are aware that allergic symptoms are caused by the release of powerful signal substances such as histamine that can cause everything from mild reactions such as a runny nose or skin rash to severe symptoms such as asthma, eczema and even systemic shock. But it wasn’t until the 1980s that scientists understood how these symptoms came about – or the central part that IgE antibodies played in the process. In principle, allergic reactions are misguided inflammatory reactions triggered by normally harmless substances from our day-to-day environment – allergens. An allergen is typically a protein found in for example plant pollens, animal dander and foods such as peanut, egg and milk. In allergic individuals, one or more of these allergens may be recognised as potentially dangerous. On first exposure, their immune system starts to produce antibodies that can bind to that antigen to protect the individual in the future. In atopic allergy (the most common type of allergy), the antibody formed is IgE. It was discovered that an allergic individual’s ‘memory’ of having first been exposed to an allergen is stored as IgE antibodies attached side-by-side on a special type of white blood cell. These blood cells, known as mast cells, contain the powerful signal substances that on their release create the inflammatory response we call allergy. On second exposure, sensitized individuals may suffer a reaction if the allergen cross-links adjacent IgE antibodies, triggering the release of the inflammatory chemicals from inside the mast cell. This is why measuring levels of IgE antibodies in blood is a good way of determining the risk of allergic reaction, and why IgE-testing is still a leader in allergy diagnostics. The rest is history. IgE history.
Research in the 80’s demonstrated exactly how IgE binds to other compounds, based on a deeper insight into IgEreceptors, which opened the door to a better understanding of the origin of allergic symptoms.