Functional Medicine Journal

Allergies are overreactions of the immune system. The immune system is a very complex interconnected network, comprising the various different white blood cells (lymphocytes, granulocytes, macrophages, mast cells), as well as the entire system of mucous membranes throughout the body, but especially in the digestive system, where specialized lymphatic tissue, called Peyer’s patches, and an immunoglobulin called secretory IgA play an essential role in the Gut Associated Lymphoid Tissue or GALT. Secretory IgA is essential for the healthy immune functioning of the gut because it will form antigen antibody complexes within the digestive tract allowing the complex to be excreted in the stool, thus preventing the adhesion of antigens to the epithelial lining. Another essential component of the immune system is the normally present bacterial colonies in the mucous membranes of the gut.

An allergy begins long before the manifestation of allergic like symptoms. The body has to be set up to respond to an allergen. This usually begins in early childhood. It takes a disturbed intestinal environment, the internal terrain of the body, for the body to react allergenically. Unfortunately this disturbance to the intestinal environment often goes unnoticed, since it is chronic, and tends to build up over many years.

Dysbiosis is one of the major disturbances to the intestinal environment leading to the presentation of allergenic symptoms. Dysbiosis can be described as an abnormal intestinal flora and an abnormally permeable intestinal mucous membrane. The intestinal flora, comprising of billions of bacteria, forms a fine film on the inside of the intestines. Everything you eat passes through this bacterial layer, which alters and filters the foodstuffs. The build up of pathogenic bacteria, yeast and parasites severely impairs the absorptive ability of the intestinal mucous membranes.

Functional hypochlorhydria and pancreatic insufficiency cause the maldigestion of carbohydrates, fats and proteins. Large macromolecules are left undigested and form the substrate for dysbiosis formation. Over time the villi, the large absorptive surface of the intestines, becomes irritated and inflamed due to the production of destructive enzymes and toxins from the dysbiotic pathogens. This causes the villi to become less dense and the intestinal lining to become “leaky”. With the destruction of the villi comes the reduction of the GALT and the secretory IgA, the body’s first line defense against “foreign” invaders. Large, incompletely digested macromolecules, especially proteins, start to penetrate the hyperpermeable intestinal mucous membrane and enter the blood stream. Once in the bloodstream, the body’s immune system recognizes the small, incompletely digested macromolecules as foreign, and produces antibodies against it. These antigen-antibody complexes circulate in the blood stream, migrating to various tissues in the body. It is the reaction of the antibody/antigen complex systemically that produces the classic allergy symptoms.

The body’s second layer of defense lies in the liver. The liver normally screens the blood for antigens. On each pass through the body, the blood must pass through the liver for cleaning and detoxification. The liver normally takes these foreign substances and destroys them or gets them out of the body. Unfortunately, liver dysfunction is a very common occurrence in our society. The destruction of foreign substances will not occur if the liver is not functioning as it should, if there is too much of the substance to get rid of easily or the liver’s phase I and II detoxification pathways cannot destroy it.

Over 80% of the human immune system is situated alongside the intestines. It is therefore understandable that disturbances of the intestines and the intestinal flora place a tremendous overload on the immune system, which then often reacts “allergically” to otherwise quite innocuous proteins. Allergies are usually indirect ailments of the intestinal mucous membrane. Thus, in treating allergies, the greatest attention needs to be given to assessing the health of the mucosal barrier, identifying whether or not the patient has dysbiosis, restoring the intestinal flora and repairing the intestinal mucous membrane.

In our experience working with physicians, the health of the mucosal barrier is not routinely assessed. The key is to identify the primary cause and extent of increased intestinal hyperpermeability. The test we recommend is the Mucosal Barrier Function Test.

The Mucosal Barrier Function Test

The Mucosal Barrier Function Test measures the serum levels of IgG, IgM and IgA antibodies to five combined dietary proteins (wheat, corn, soy, milk, and eggs), yeast (Candida albicans), two aerobic bacteria (Bacteroides fragilis and Clostridium perfringens), and two anaerobic bacteria (E. coli and Enterococcus) using the ELISA method of analysis.

How is the Mucosal Barrier Function evaluated?

The Mucosal Barrier Function Profile measures the health of the mucosal barrier lining of the GI tract from a functional standpoint. A healthy mucosal barrier will have secretory IgA (sIgA) levels in normal range and will show normal recognition of food proteins, enteric yeasts and enteric aerobic and anaerobic bacteria. This means that IgA, IgM and IgG levels to food proteins, enteric yeasts and enteric aerobic and anaerobic bacteria are all within normal range.

What if the mucosal barrier does not recognize normally encountered antigens?
If the mucosal barrier has shut down, the results for IgA, IgM and IgG levels to food proteins, enteric yeasts and enteric aerobic and anaerobic bacteria will all be <400. A continuum of events can lead to the complete shutdown of the mucosal barrier. When a healthy mucosal barrier is first challenged by an infectious agent, sIgA rises and elevations of specific antibodies may occur. At this point the antigen load is compartmentalized within the GI tract. As the infection begins to overwhelm the mucosal barrier defenses, the humoral immune system becomes more involved by increasing the number of circulating antibodies.

As an infection overpowers the mucosal barrier defenses, at some point the tight junctions between the intestinal cells open up and antigen penetration into the general circulation increases resulting in an increase in allergy and inflammation. Also, if any one of the three antibodies (either IgA, IgM or IgG) are elevated in each of the four compartments on the Mucosal Barrier Function Test (dietary proteins, yeasts, anaerobic bacteria, and aerobic bacteria) this would indicate hyperpermeability in the intestinal mucosal lining.

If no intervention occurs, eventually the mucosal immune response begins to weaken and can eventually shut down. As time goes on it loses its ability to recognize and process antigens properly. Ever increasing antigen penetration can eventually result in overstimulation of the humoral immune system leading to hyper-immune response and eventually the humoral immune system burns out.

If a hyper elevated or shut down mucosal barrier and/or leaky gut is confirmed, it is extremely important to identify the cause.
Suspect: Increased intestinal permeability or “leaky gut”

Possible Causes

1. Exposure to toxic substances (drugs such as NSAIDS and alcohol, chemical exposure)2. Food allergy/intolerance
2. Intestinal dysbiosis
3. Parasite, yeast, viral, or bacterial infection
4. Maldigestion (includes hypochlorhydria, pancreatic insufficiency, and disaccharidase insufficiencies)
5. Bacterial overgrowth of the small bowel
6. Prolonged fasting/nutrient insufficiencies
7. Inflammatory bowel disease, e.g. Crohn’s disease
8. Insufficient mucosal glycocalyx and/or sIgA

Finding the cause of a patient’s intestinal impermeability will help you determine the direction of treatment. It’s important to remember that correcting intestinal hyperpermeability can take quite a long time, especially as it’s often taken years to develop. Fortunately, the gut tends to be a responsive organ, and correcting its imbalances can reverse longstanding, painful symptoms.

For more information on this test please visit this site: http://www.mucosalbarrier.com/