Many people with asthma find their conditions are exacerbated by inhaling certain allergens (e.g., pollen, mold, dander, dust mites). In susceptible individuals, the allergic reaction results in swelling in the nasal passages and airways, making it hard to breathe and triggering an asthma attack. The inflammation that takes place during this process is caused by the release of IgE antibodies into the bloodstream.

When an allergen enters the body of an allergic individual – through the respiratory tract (nose, throat and lungs) in the case of allergic asthma – it stimulates the immune system to prepare to repel the invader. This is a process known as sensitization. T-cells recognize the allergen as a threat and send a signal to certain B-cells, which begin to produce IgE antibodies. The IgE antibodies that are produced are specific to that allergen, and will not react with other types of allergens. In this way the IgE antibodies allow the immune system to recognize a particular allergen if it is ever encountered again.

If a person does encounter an allergen after being sensitized to it, the immune system responds with a full-blown allergic reaction. The IgE antibodies, which have attached themselves to mast cells and basophils throughout the body, trigger these cells to release inflammatory chemicals such as histamine into the bloodstream. The resulting inflammation these chemicals create in the airways and nasal passages can trigger an asthma attack in susceptible individuals.

Anti-IgE antibody treatments work by interrupting the normal function of IgE in the allergic cascade. This treatment is the first biological therapy approved by the U.S. Food & Drug Administration (FDA) to treat moderate to severe allergy-related asthma. It is also called a monoclonal antibody because the drug introduces a specific type of antibody to the body.

The anti-IgE antibody treatment prevents the body's IgE antibodies from binding to the mast cells and basophils. The anti-IgE antibodies interfere with the receptors on the mast cells and basophils so that IgE antibodies cannot attach to these cells. This effectively blocks any interaction between IgE antibodies and mast cells or basophils, and prevents the subsequent release of inflammatory chemicals. The antibodies also combine with IgE in the blood, which may help the body get rid of them.

Anti-IgE antibody treatments are given through regular injections, usually one every two to four weeks. The injection is usually performed under a physician’s supervision, though some individuals who require more frequent injections may self-administer the treatment.

Dosage should be determined by a physician, who will take into account the patient’s size and natural level of IgE (as measured by a blood test). The size of the required dose will determine whether a patient will receive one, two or three injections per dose. Individuals who require multiple injections per dose will receive each shot in a separate place on the body. 

Asthma symptoms may not immediately improve after taking an anti-IgE antibody treatment, and it often takes several treatments for the therapy to take full effect.  Anti-IgE treatments may prove to be effective at reducing reactions to allergens, but they are not currently approved for use as an allergy treatment.

Anti-IgE treatments have been available in the United States for only a short period of time as the FDA only approved the first anti-IgE antibody treatment (omalizumab) in 2003. For this reason, it is unclear what the long-term effects of the treatment may be. At this point, many physicians use the therapy only for asthma that is not adequately controlled with corticosteroids. Any individuals interested in taking this treatment should discuss the pros and cons of its use with their physician.

Anti-IgE antibody therapies have the potential to be a revolutionary new type of treatment for allergies and allergic asthma. Because they can prevent allergies from ever taking place, future therapies could make the diagnosis of specific allergy conditions unnecessary. Many different clinical studies are currently taking place to evaluate the possible uses of these drugs.

It is important to note that anti-IgE antibody treatments are designed to be used in conjunction with inhaled corticosteroids. It is not a substitute for the other asthma medications a patient has been prescribed. Therefore, patients should not discontinue the use of, or change the dose of, their other asthma medication unless a physician advises them to do so.