As allergies become increasingly prevalent they affect 50 million Americans, and counting researchers are working hard to come up with ways to treat allergies and trying to learn more about the underlying reasons allergies occur. While the mechanisms of the allergic response are well-understood, it remains a mystery why some people experience allergic responses while others dont. The Wall Street Journal recently reported on the work of two researchers who are examining this very question.
Allergen Structure Research
Anna Pomes and Martin Chapman, two researchers based in Charlottesville, VA are focusing on obtaining the answer to why allergies occur in some individuals but not others. The ultimate goal is to create safer and more effective treatments for allergy sufferers and even to develop vaccines that will prevent allergies in the first place.
In order to do this, the researchers are studying the DNA makeup and shape of allergens and how allergens interact with the immune system. Dr. Pomes points out, "Allergens are everywhere and in high amounts. If we know the structure, we can figure out how structure can influence immunogenicity," meaning how potent they are in inducing allergic reactions.
Knowing how structure affects potency is a major step in understanding allergens behavior in the body. For example, the allergen in peanuts, one of the most allergic foods, does not degrade easily; its relatively stable structure allows it to linger in the body.
One discovery made by the research duo is the determination of the structure of two dust mite allergens. In addition, they have discovered the site on the cockroach allergen where the allergy antibody binds, causing the allergic reaction.
How the Shape of Allergen DNA is Determined
The first step Drs. Pomes and Chapman took in order to determine the shape and structure of allergens was cloning allergens. They figured out the DNA sequence of their proteins, then made additional copies of the DNA and purified them from other particles.
Working with other scientists, they subsequently created crystals from the proteins and then froze them. A synchrontron, which spins the particles around so fast they create x-rays, allowed them to determine the proteins shape. In this way, they mapped out the allergens structure.
Allergen Structure and Allergy Treatments
So how does knowing the structure of allergens help allergy sufferers? Scientists hope that immunotherapy using mutant forms of the allergens could be used to treat allergic individuals, especially those for whom medications dont work. Changing even one amino acid in the protein of the allergen can affect the tightness with which the allergen binds to the antibody. A weaker bond could reduce the allergens potency in triggering symptoms.
Immunotherapy involves injecting allergic individuals with tiny amounts of the substance they are allergic to in order to hopefully desensitize their bodies so that eventually their immune systems wont react to offending allergens. Using mutant allergens could make the treatment safer than using the actual allergen, a process which can, though rarely, produce a fatal response in the patient.
More About Immunotherapy
Allergy medications offer relief from allergy symptoms, but do nothing to alter a persons response to allergens. Immunotherapy attempts to do just this by desensitizing the immune systems reaction. The treatment is already being used to treat life-threatening allergies such as peanut allergy or milk allergy, and studies have shown the therapy to be effective.
A recent study conducted by the Duke University Medical Center, for instance, showed that over a six-month period, peanut allergic children went from ingesting 1/1,000 of a peanut to 13 peanuts without experiencing symptoms.
According to the Asthma and Allergy Foundation, immunotherapy is recommended for patients whose allergies last more than a few months per year and who are already on several allergy medications.
The Immune Systems Response to Allergens
Scientists understand that allergies are caused by the bodys immune response to particular allergens, such as dust mite allergen, pollen, certain foods, mold, and pollen, to name some of the most common. Specifically, the allergens are usually proteins, which themselves are long chains of amino acids folded into complex shapes.
Allergens are not actually harmful to the body, but allergic individuals immune systems perceive them as a threat. In response, the immune system produces immunoglobulin, or IgE, antibodies that trigger the release of histamine and other substances, which are responsible for allergy symptoms.
WebMD offers the following step-by-step breakdown of what happens during an allergic reaction:
First, a person is exposed to an allergen by inhaling it, swallowing it, or getting it on or under their skin. After a person is exposed to the allergen, a series of events creates the allergic reaction:
- The body starts to produce a specific type of antibody, called IgE, to bind the allergen.
- The antibodies attach to a form of blood cell called a mast cell. Mast cells can be found in the airways, in the intestines, and elsewhere. The presence of mast cells in the airways and GI tract makes these areas more susceptible to allergen exposure.
- The allergens bind to the IgE, which is attached to the mast cell. This causes the mast cells to release a variety of chemicals into the blood. Histamine, the main chemical, causes most of the symptoms of an allergic reaction.
While research in this field is constantly evolving, a better understanding of how allergens actually cause a reaction may one day lead to the ability to greatly reduce or erase allergies all together. And though advancements in the field have been extensive, the fact remains one of the easiest ways to control your allergies is through environmental control. While you cannot control the larger world around you, places like your home, workplace or car, can be. So, whether it is as simple as placing an air purifier in your bedroom, using a HEPA vacuum cleaner in your home or wearing a mask while doing yard work, jogging or walking, there are many steps you can take to help avoid allergens and the harmful reactions they can cause you.