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There are many ways to think of the human body. One of my favorites is that the body is like a donut. The inside of the donut is our entire body and everything that makes us what we are. The outside is our skin. The hole in the middle is made of our mouth, throat (esophagus), stomach, and intestines. The body treats the entirety of the digestive tract as the outside world. The intestines act like the skin; keeping most things out of the body and only letting specific molecules through.

This has some important implications. The whole outside of the donut – including the throat and intestines – is covered in epithelial cells. These are tight cells that interact with the outside world. When these cells determine that they are touching something dangerous they signal to get rid of it immediately. This might feel like burning or itching on the skin, and may be something like diarrhea or vomiting in the digestive tract. These may feel crummy to us, but they are very useful in keeping us safe.

The immune system is in charge of identifying and reacting to chemical and biological dangers. These can be harmful bacteria, worms, and things like splinters or some drugs. The immune system kicks into action, trying to kill or remove the dangerous particles without damaging body cells. This is a tricky dance. Antibodies will identify the dangerous particles or creatures and special B or T cells will widely sprinkle alarm particles, calling for reinforcements.

What the body does next is determined by where the danger is found. In the gut – which the body treats as the dangerous outside world – the defenses are strong. One of the biggest guns we have is a cell called an eosinophil. These are very dangerous cells. They contain highly toxic particles and proteins that aggressively dunk in on invaders. They also signal to the intestines to  contract and eject the contents. They only exist in specific parts of the body and are normally difficult to activate.

Unfortunately, sometimes our body identifies otherwise safe items as dangerous. This is called allergies, and can be very annoying. Many of us suffer from seasonal allergies, but that doesn’t mean we should glaze over the dangers of allergic reactions. One difficult condition is eosinophilic esophagitis. Eosinophilic means it is caused by the dangerous eosinophil cells. Esophagitis refers to the fact that this happens in the esophagus, the throat. Eosinophils do not normally reside in the throat at all. The throat’s main job is to move food into the stomach, so it doesn’t need to detect danger. When eosinophils mistakenly reside in the throat, however, they can misidentify otherwise safe foods before the stomach gets a chance to digest them. This can result in the eosinophils damaging the throat.

Eosinophilic esophagitis affects four in every thousand people, and can affect people of all ages. Most sufferers were diagnosed as children. In fact, it is one of the most common diagnoses for children who have trouble eating. It is chronic, or long lasting,  and symptoms are debilitating. Sufferers experience inflammation of the throat, poor food intake, vomiting, and a poor appetite. Unfortunately there are few treatments available to fix this condition. The most effective has been reducing the diet of patients. This may consist of starting with a very strict diet and reincorporating food slowly to discover triggers. Scientists are actively looking at the underlying causes of why eosinophils are in the throat to begin with. Possible future treatments would likely stop eosinophils in the throat at a cellular or genetic level.  The body may be a donut, but that doesn’t mean everything is tasty and fresh. If you are suffering from eosinophilic esophagitis or other conditions, call ENCORE Research Group and ask about studies you may qualify for.

By Benton Lowey-Ball, BS Behavioral Neuroscience

Furuta, G. T., & Katzka, D. A. (2015). Eosinophilic esophagitis. New England Journal of Medicine, 373(17), 1640-1648. https://doi.org/10.1056%2FNEJMra1502863

Janeway Jr, C. A., Travers, P., Walport, M., & Shlomchik, M. J. (2001). Effector mechanisms in allergic reactions. In Immunobiology: The Immune System in Health and Disease. 5th edition. Garland Science. https://www.ncbi.nlm.nih.gov/books/NBK27112/

Rothenberg, M. E. (2004). Eosinophilic gastrointestinal disorders (EGID). Journal of Allergy and Clinical Immunology, 113(1), 11-28. https://doi.org/10.1016/j.jaci.2003.10.047

Zuo, L., & Rothenberg, M. E. (2007). Gastrointestinal eosinophilia. Immunology and allergy clinics of North America, 27(3), 443-455.https://doi.org/10.1016%2Fj.iac.2007.06.002