Signaling Molecules

Here's another excerpt from the new Education Modules.​ It begins the discussion of what are called signaling molecules. They are very important to the immune system, and to people who suffer from allergies and sensitivities.

When immune cells are excited by antigens, they release signaling molecules that do things important to immune function. Unfortunately, they also cause local target organ dysfunction and systemic symptoms. In modern parlance we might think of this as “collateral damage.”  Each SM produces its own signature of symptoms. We’ll discuss the symptoms as well as why immune cells release them.

Histamine is a big one and responsible for two main effects in an inflammatory response: dilating blood vessels and making them more permeable to allow more fluid to pass from the bloodstream into the tissues. This allows for reinforcements to arrive but also results in localized swelling, edema, and redness. Recall that I said symptoms related to allergy and sensitivity responses are caused by chemicals released by cells of the immune system, not by the allergen itself.

Systemic histamine release causes the following symptoms:

Headache. A pulsating, whole-head pain, often with a sense of great pressure or a feeling of bursting within the head

Fast pulse, low blood pressure, irregular heart beat

Itching or burning followed by flushing and an unpleasant heat

Increased stomach acid release with crampy abdominal pain

An asthma attack may be provoked

Anxiety and agitation with a diffuse, odd body sensation sometimes colorfully described as “my bones are on fire”, “I feel weird all over”, “a deep pricking, crawling sensation.”

I heard descriptions like these often in practice. Especially the “I feel weird all over” and “a deep pricking, crawling sensation” when there was nothing visibly wrong with the skin.

Heparin is an anti-clotting SM that inhibits thrombin, which aids in blood coagulation. This allows more blood to flow to the inflamed site. It’s typically released with histamine and is made inside mast cells. When heparin is released, it causes the formation of bradykinin, which we’ll discuss in a minute. 

Serotonin plays a role in sensitivity responses, especially with foods. It makes the gut contract, moving food through the intestines. When irritants are present, more serotonin is produced to make the gut move faster, to get rid of the irritants quicker. We call this diarrhea. If too much serotonin is released into the bloodstream, it will stimulate vomiting. Most people think of serotonin only as a neurotransmitter that affects mood, but I bet you didn’t know that 95% of serotonin is produced and found in the GI tract.

Leukotrienes are found in cell membranes and play a key role in asthma in three ways: they cause inflammation, bronchoconstriction, and mucus production. They also contribute to skin inflammation in psoriasis, inflammatory bowel diseases, and the inflammation in nasal passages that occurs in allergic rhinitis.

Prostaglandins are hormone-like substances that regulate cell function throughout the body. There are a number of them, some with positive effects, some with negative. Symptoms they produce include flushing, pain, shortness of breath, fast heart rate, constricted or dilated blood vessels, diarrhea, and abdominal cramps.

Bradykinin is released when mast cells and basophils split open, and, as we learned is stimulated by heparin release. It causes pain by stimulating nerve endings and causes the blood pressure to drop by dilating peripheral arteries. Bradykinin can cause angioedema, which, if it occurs in the tongue or larynx can cause death by asphyxiation.

* Some of this information came from "Food Allergy," a PDF ebook by Stephen J. Gislason MD. It's a highly recommended reading, though Dr. Gislason doesn't think much of sensitivity elimination therapies. The site instead advices a dietary clean-up and sells products to support that. (The website appears to need some modernizing.)