Immunoglobulin E (IgE) is an antibody which plays a vital role in development of allergic reactions and asthma. All humans have certain types of cells which protect the body against foreign organisms like bacteria and viruses. These cells make a variety of antibodies that help fight off a variety of infections; we have 5 basic antibodies in our blood. Antibodies are vital for survival and without antibodies; one would be prone to many types of infections. One type of antibody which is of importance in protecting the lung, skin and intestine is the IgE antibody. The IgE has a propensity to react against pollen, fungus spores, certain milk products, drugs and plants. IgE antibody levels are often increased in individuals whom have allergies. This antibody also helps to protect as against a variety of parasites.

Levels of IgE antibodies in the blood are normally quite low. However, the body does have an intricate communicating system and can respond with large amounts of antibody if a need arises. There are some cells which wander in the circulation like “soldiers” and if they perceive any threat from outside, they send signals for the body to make more antibodies.

Once the IgE antibody is made, it will attach itself on to certain cells like mast cells and basophils. These cells also play a role in allergies and contain a vast number of potent chemicals. When the antibody reaches a site where the foreign organism has entered, it unleashes a powerful reaction and the cells release their potent chemicals which destroy the invader. Once the foreign body is recognized it is etched on in memory of the IgE antibodies which will respond harshly if a repeat invasion occurs.

For example in asthma it is believed that allergens enter the lung and encounter the IgE antibody. The IgE antibody attacks the invader and induces the body’s cells to release a variety of chemicals. Unfortunately sometimes the chemicals released also damage the body. In asthma the episodes of wheezing and mucus generation are believed to be due to a hyperactive response by the IgE antibody. A similar scenario is encountered in people who have skin allergies. One of the chemicals released by the IgE antibody is histamine which induces wheezing, causes chest tightness, fast heart rate, drops blood pressure and induces skin flushing. This is the reason why anti histamines are backbone of any allergic reaction. These drugs quickly block the response of histamine and prevent the symptoms from occurring or getting worse.

Unfortunately, the effects of drugs are broad and side effects are common. With better understanding of the IgE molecule, more sensitive and precise drugs have been developed to treat people whom are allergic.
Immunoglobulin levels can be measured in the blood, but are not always useful because there is no direct correlation between symptoms and blood levels of antibodies. Immunoglobulin levels are only measured for diagnostic purposes to ensure that the body does in fact respond to a challenge when a foreign material is introduced. There is no direct correlation between levels of IgE in the blood and the allergic reaction.
Without Immunoglobulin e one would be prone to a variety of bacterial infections and parasites, but sometimes a hypersensitive response by this antibody can result in development of allergies.