This article was originally posted on RealClearScience.

The adaptive immune response is the branch of our immune system that most people are familiar with. It’s the reason vaccines work. When exposed to a molecule that triggers an immune reaction (known as an “antigen”), the body produces antibodies that specifically bind to that molecule, eventually leading to its destruction. The most common class of antibody produced is called immunoglobulin G (IgG).

Our bodies can also produce a less common type of antibody called immunoglobulin E (IgE). Notably, IgE helps fight off parasitic infections, but other than that, its role is largely unknown. In the developed world, parasites are no longer a major concern, so immunologists believe that IgE occupies its time by causing trouble, instead.

If you have allergies, blame IgE. For some reason, benign substances such as peanuts and cat hair can incite our immune system, which kicks out gobs of IgE. These antibodies then bind to an immune cell called a mast cell, triggering it to release a bunch of chemicals which produce all the symptoms we commonly associate with allergies — sneezing, coughing, itchiness and overall misery. In worst case scenarios, an out-of-control allergic response called anaphylatic shock occurs. This can be deadly.

Does IgE have any modern-day redemptive qualities? According to new research in the journal Immunity, the answer is yes. Continue reading →