Every day, roughly three million Canadians experience a reaction to chemical compounds ranging from sneezing, coughing, and a runny nose to life-threatening circumstances such as anaphylactic shock.
But these chemical compounds aren't the dangerous or toxic stuff found in movie plots and terrorist activities nor are they the byproducts of the chemical industry run amok. These are the ordinary chemical compounds of everyday life - pollens, grasses, bee venom, milk, and even peanut butter. They are the chemical compounds that make up the environment around us.
Allergic reactions affect one in every 10 people. Allergic reactions are some of the most common complaints that individuals have when seeing their doctors. And by all accounts, the number of severely allergic individuals is increasing, although that is a statistic that must be taken with a grain of salt as there are many other factors that come into play. So, what exactly is an allergy?
An allergic reaction occurs when the body develops an immune response to a foreign substance called an "allergen". In essence, the body tries to eliminate any foreign substance it finds through the use of the immune system. Indeed, one of the primary tasks for the immune system is to build special cells that travel throughout the body looking for substances that do not belong there. When they find one of these substances, they deal with it.
As we are continually subjected to a barrage of bacterial, viral, parasitic, and fungal diseases, without our immune system to defend us, we would never have evolved into complex organisms in the first place.
Critical to being a multicellular organism is being able to identify "self" from "non-self" and to be able to eliminate "non-self". Indeed, this was the first step in the long road to the evolution life as we know it. (The perpetual defence of the body from invaders is why immune deficiency diseases, such as HIV, are so deadly. The disease's virus doesn't kill its host individual but by compromising the immune system, it makes sure that any and every other pathogen will.)
The way that the immune system protects our bodies is through the synthesis of "immunoglobulins" or antibodies. These are protein molecules. They are very large chemical molecules composed of thousands or millions of atoms linked together in peptide units. All of the immunoglobulins have much the same shape but each has unique receptors designed to recognize and bind a specific "antigen". In the case of an allergic reaction, the antigens are the allergens and they may be anything - from dust mites to pollen grains to food products.
A specific type of immunoglobulin, designated IgE, is found in large quantities in the blood of individuals who suffer from allergies. Scientists believe that it is responsible for the immunological response to allergens. That is, the reaction of IgE to an invading allergen is to attack it and this produces a response which is typically a running nose, a cough, or a mild rash. Most of these responses have to do with eliminating the allergen from the body. For example, as annoying as a sneeze is, it is the body's way of expelling material from the airway with sufficient force to ensure that it gets removed from the body.
However, sometimes the IgE induced response is way out of proportion to the amount of allergen present in the body. People die from bee stings or eating seafood or peanuts because of the resulting response of the body to the allergen. Our immune system is trying to protect us from an invasion of chemicals but it just gets carried away. Some medical professionals argue that the increasing number of individuals that have allergies is a result of not exposing our immune system to a wide enough variety of allergens early enough. We need to let children eat a "peck of dirt" as my mother would say to ensure that their immune system develops appropriate levels of response.
We are chemical beings and we respond to all of the chemicals in our environment, even though we often call these chemicals by many different names such as food or drink or pollen or dust. Pretty much everything around us is made up of complex molecules. When we ingest, inhale, or take in these compounds by other methods, the antibodies of our immune system determine if they are friend or foe and whether or not they should be eliminated.
In fact, the whole point of the immune system is to eliminate the foes in order to save the friends. And foes may be anything but for those of us allergic to tree pollen, this is a very bad time of year because despite our lingering winter, my allergies are starting to kick in.
Please excuse me while I go and sneeze.
