Why are we allergic?

Autumn is coming, and the season of allergies is coming again. Do not look at the increasing number of people with allergies today, the proportion of allergic people in developed countries has exceeded 20%, but the term allergy was not created until the early 20th century. Research on allergies is also seriously lagging behind. Scientists only know that allergies are caused by excessive activity of the immune system, but so far they still don’t know what causes allergies and what kind of people are more susceptible to allergies.

The most important thing is that scientists have been unable to understand why we are allergic, and what is the significance of our ancestors to advanced this function. About half a century ago, doctors discovered a parasite called worm that stimulated the body to produce large amounts of immunoglobulin E (IgE), the most important marker of allergic reactions, so some people speculated that allergies were initially It was evolved to deal with worms. Unfortunately, this defense mechanism is too easy to miss the target, which leads to allergies. However, later generations found that IgE does not kill worms.

What really works is interleukin, which has nothing to do with allergic reactions. In 1991, evolutionary biologist Maggie Profetter of the University of California at Berkeley proposed a new interpretation of the allergic reaction intended to help the body fight environmental toxins. It is important to know that most allergens are toxins in nature. For example, the macromolecular compounds in many plants are actually insecticides. Unfortunately, because Profite is not studying immunization, the hypothesis she proposed is not accepted by the mainstream scientific community.

Almost at the same time, a Russian graduate student named Roseland Meztov came to Yale University in the United States to study under the school’s famous immunology professor Charles Jenway. The latter believes that although antibodies are useful, it takes time to produce antibodies, so the body should have a separate defense system designed to deal with emergencies. As long as the appearance of the invading enemy looks like a similarity to the enemy it has encountered before, the system will immediately attack it.

It was during the study of this set of defense systems, which were later called “natural immunity,” and Mr. Meztov realized that the explanation that Profite proposed in the past might be correct. Since then, Meztov has devoted himself to studying allergies, and An important paper was published in the 2012 issue of Nature, explaining his point of view. Meztov cited four reasons: First, common allergic symptoms include sneezing, runny nose, tearing, diarrhea, and vomiting, which are similar to the process of detoxification. Second, allergic reactions occur very quickly, even after a few seconds of exposure to allergens, which is more in line with the detoxification process, not so much as to deal with parasites.

Third, allergic people are very sensitive to allergens, as long as there are traces of allergens in the environment. Be aware that even with infectious agents such as germs and viruses, the human immune system is not as sensitive, let alone worms. Fourth, the ingredients of allergens are extremely diverse, ranging from small molecule compounds in penicillin to complex proteins in animal venom, which is not explained by worm theory. After the publication of this paper, several laboratories have found more reasons to prove that this explanation is likely to be correct.

For example, the human body’s perception of environmental toxins is formed during infancy. The reason why allergies in modern society are more and more, it is probably because the environment of life is too clean and has not touched dirty things. For example, modern people have more opportunities to travel, and they are farther and farther away. They are more likely to be exposed to new things that are less likely to be exposed when they are young. The human body can’t adapt to this new way of life, which leads to more Allergic reaction.