The Mucosal Barrier Function Test : The Gut Connection to Allergies

Dicken Weatherby, ND and Ron Grisanti, DC

Allergies are overreactions of the immune system. The immune system is a very complex interconnected network, comprised of the various white blood cells (lymphocytes, granulocytes, macrophages, mast cells) as well as the mucous membranes throughout the body. It is especially complex in the digestive system, where specialized lymphatic tissue, Peyer’s patches, and the immunoglobulin secretory IgA play an essential role in the Gut Associated Lymphoid Tissue (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 billions of bacteria, forms a fine film on the inside of the intestines. Everything we eat passes through this bacterial layer, which alters and filters the foodstuffs. The buildup 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 become 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 bloodstream. Once in the bloodstream, the body’s immune system recognizes the small, incompletely digested macromolecules as foreign, and produces antibodies against them. These antigen-antibody complexes circulate in the bloodstream, migrating to various tissues in the body. It is the reaction of the antigen-antibody complex systemically that produces the classic allergy symptoms.

The body’s second layer of defense lies in the liver, which 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 if the liver’s phase I and II detoxification pathways cannot destroy the substance.

More than 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.

Mucosal Barrier Function TestA healthy mucosal barrier will have sIgA levels in normal range and will show normal recognition of food proteins, enteric yeasts, enteric aerobic and anaerobic bacteria

The mucosal barrier function test was developed because microbial flora imbalance cannot be fully understood in its diagnostic and therapeutic implications without coordination of the intestinal flora, including the dietary proteins. The mucosal barrier function test utilizes a highly sensitive and accurate ELISA test method that measures serum IgG-, IgM- and IgA-specific antibody titers to the purified antigens from five dietary proteins, several enteric bacteria (three aerobic, two anaerobic) and three strains of Candida.

The test only requires two milliliters of serum. False negatives for antibodies to Candida, which might be associated with a compromised immune system, can be ruled out by concomitant assessment of antibody titers for dietary proteins and GI bacterial flora. Likewise, abnormally low levels of antibodies for the array of antigens are indicative of immunodeficiency.

Evaluation of the Mucosal Barrier Function

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 these food proteins and organisms are all within the normal range.

Recognition of Unusual 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 <400ng/mL. 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.

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

If no intervention occurs, eventually the mucosal immune response begins to weaken and can 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 (see the accompanying list of possible causes).

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

Possible Causes of Increased Intestinal Permeability

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

WeatherbyDicken Weatherby, ND is based in southern Oregon. A graduate of NCNM, Dicken is co-author of the bestselling book Blood Chemistry and CBC Analysis-Clinical Laboratory Testing from a Functional Perspective. He has self-published seven other books in the field of alternative medical diagnosis, has created numerous information products, and runs a number of successful Web sites (www.BloodChemistryAnalysis.com, www.Health-E-Marketing.com and www.StrawBale.com). He is involved in research, writing and consulting, and teaches functional diagnosis seminars in both the U.S. and his native country, the U.K.

Ron Grisanti, DC has been practicing in Greenville, SC for 26 years. He is a board-certified chiropractic orthopedist and has his master’s degree in nutritional science from the University of Bridgeport. He is actively involved in teaching a nutritional, functional medicine-based practice to chiropractic physicians.

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