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HEALTH CONCERN? BioHealth Health Concerns

Core Systems of Function - Immune System


The first line of defense against disease-causing microorganisms is the skin and mucosal barriers. Behind this is a complex defensive system. Collectively these parts are known as the immune system.

The immune system neutralizes or destroys microorganisms and the toxins created by them wherever they attack the body via the extensive lymphatic system (comprised of the spleen, thymus gland, tonsils, bone marrow, and other organs and tissues). The network of lymph vessels (capillaries and lymphatics) drains the clear body fluid known as lymph from the tissues into the bloodstream. Special white blood cells that originate in bone marrow, known as lymphocytes, along with antibodies (proteins that neutralize foreign objects), are primarily responsible for carrying out the work of the immune system.

The first line of immune defense is called the mucosal barrier. Mucous membranes are an integral part of the immune system. They form a protective barrier between the interior of the body and the outside environment. The mucosal barrier is permeable and allows nutrients into the body while protecting it from infectious agents, allergens, and other harmful substances. If testing reveals that mucosal immunity is impaired, therapies should be initiated to rebuild it.

Cellular and humoral immunity. In addition to evaluating mucosal immunity, it is relevant to assess cell-mediated immunity and humoral immunity. Cell-mediated immunity works by the activation of specialized cells called macrophages and natural killer cells, which destroy intracellular pathogens (disease-causing microorganisms). Humoral immunity is the aspect of immunity that involves antibodies. Knowing the status of these immune components provides a comprehensive understanding of one’s ability to fight infectious agents, defend against toxic exposures such as chemicals and heavy metals, and kill aberrant cancer cells.

The Mucosal Barrier: Your First-line Immune Defense

The mucosal barrier refers to all of the mucous membranes that comprise the primary interface between the external environment and the internal environment of the body. Mucosal barriers line the surfaces of your eyes, ears, nose, sinuses, mouth, throat, gastrointestinal tract (from mouth to anus), respiratory tract, urogenital tract, and the vaginal tract.

An analogy can be made between the earth’s ozone layer and your body’s mucosal barriers. The ozone layer lets the right amount of sunlight through, sustaining life on earth; your mucosal barriers allow nutrients through, sustaining your health. The ozone layer prevents harmful levels of radiation from getting through; the mucosal barriers prevent infectious agents and allergens from invading your body. However, just as the earth has a damaged ozone layer, many of us have compromised mucosal barriers that fail to protect us from infectious agents, allergens, and other harmful substances.

This image shows a healthy mucosal barrier on the left and a badly damaged one on the right.

Mucosal barriers

Why does one person get sick while another doesn’t when they’re both exposed to the same infectious agents? Typically, people who become ill have compromised first-line immunity. Take the example of anthrax, which caused fears of terrorism shortly after the 9/11 attacks on the United States. Individuals exposed to the anthrax spores without getting ill had healthy mucosal barriers. Those who got ill did not. Their mucosal barriers were unable to encapsulate the spores and eliminate them.

The structures of the mucosal barriers vary in appearance depending on their locations in the body. Perhaps the most important one is the barrier lining your intestines, given its sheer enormity and its role in digestion and immunity. We won’t go into great depth describing the complex components and mechanisms by which the mucosal structures function—although it is a fascinating topic for scientific minds. What is important is that you appreciate their significance and vulnerability when exposed to chronic stress, especially with regard to the gastrointestinal tract.

Secretory IgA to the Rescue

Inflammation, the result of tissue damage caused by influences such as food intolerance and parasitic infection, will erode the structures of your mucosal barrier. A structurally sound mucosal barrier is vital to preventing infection and illness—and not just because it acts as a border through which harmful substances are denied access. It is also a functional component of your immunity. A healthy mucosal barrier contains adequate amounts of secretory antibodies, which are proteins released to neutralize foreign substances that have entered the body. These mucosal antibodies are known as immunoglobulins, with the most abundant being secretory immunoglobulin A, or secretory IgA.

Secretory IgA represents 73 to 90 percent of the mucosal antibodies produced in the mucous membranes by cells called immunocytes. Less abundant are immunoglobulins M and G. All of these antibodies recognize and neutralize commonly encountered pathogens such as bacteria, fungi, parasites, viruses, and yeast. Secretory IgA also recognizes and processes the proteins in foods. When secretory IgA levels are adequate, food proteins are efficiently processed and the potential for adverse reactions, including allergies, is reduced.

Hormones play an important role in your body’s production of secretory IgA. Elevated cortisol and low DHEA create a deficiency of secretory IgA. In addition to suppressing the immunocytes that produce secretory IgA, high cortisol/low DHEA causes a state of “fight-or-flight response.” In this state, the body behaves as if under threat, increasing demands for cortisol production and creating a state of Pregnenolone Steal. The longer you remain in fight-or-flight under chronic stress, the longer it takes for the immunocytes to recover and stabilize secretory IgA production.

When stress is high, immune defenses are low.

The Danger of Immune Complexes

Each of the many offending microorganisms in our environment is unique, with its own specific antigens (proteins). The mucosal immune system needs to handle these individual antigens appropriately. When secretory IgA is deficient, the body is unable to properly process microorganisms, resulting in their increased penetration through the gastrointestinal tract and into the bloodstream, where they elicit a systemic immune response.

Your body may become overwhelmed with foreign proteins entering its bloodstream, creating antigen overload. Your systemic immunity creates antibodies that bind to antigens to neutralize them. This combined “complex” of antibody and antigen is called an immune complex or antibody–antigen complex. Accumulation of immune complexes put additional stress on your liver and kidneys, impairing detoxification. Accumulation of immune complexes also accelerate allergy and inflammation, perpetuating a vicious cycle.

Depending on where the immune complexes accumulate, the immune system may no longer be able to differentiate between these complexes and the proteins that make up our own tissues. Large immune complexes make us susceptible to autoimmune conditions—conditions in which the body, in essence, attacks itself—involving whatever tissue they enter. For example, if immune complexes invade the intestinal tract system, there is risk for autoimmune gastrointestinal conditions such as Crohn’s disease and inflammatory bowel disease.

The Risky Business of Mucosal Barrier Dysfunction

Because we’re often exposed to opportunistic organisms that can cause infections and even disease and death, our first-line immune defense must be healthy. Some of the infectious agents that our mucosal immune defense protects us from are bacteria including Clostridium, Salmonella, and Streptococcus; viruses such as herpes, HIV, influenza, poliomyelitis, rotavirus, and rubella; and intestinal parasites such as Giardia lamblia, Cryptosporidium parvum, Entamoeba histolytica, and Blastocystis hominis.

Parasites have a nasty habit of invading compromised mucosal barriers, eroding their surfaces and causing an inflammatory response, which results in the collapse of the barrier’s finger-like projections called villi. Collapsed villi can trap infectious organisms such as parasites in pockets where they thrive, perpetuating a 24/7 Chronic Stress Response and depriving the body of nutrients and immune defenses.

Another common source of mucosal tissue inflammation is reactivity to offensive foods. One of the most prevalent and destructive food molecules is gliadin, found in the glutinous portion of grains like wheat and rye. Intolerance to gliadin is referred to as gluten intolerance and is especially common in those with Northern European ancestry. When the gliadin molecule makes contact with a genetically predisposed individual’s mucosal barrier, inflammation results, damaging the barrier.

If the function of your mucosal barrier is compromised, you are at risk for common gastrointestinal diseases: autoimmune achlorhydria (inability to produce hydrochloric acid), pernicious anemia (a condition in which the body does not make enough red blood cells), villous atrophy (a breakdown of the lining of the intestinal tract leading to intestinal permeability), and infectious clostridium (the primary cause of ulcerative colitis). Moreover, a weak first-line immune defense puts you at risk for a myriad of health problems. It ensures that you remain in a Chronic Stress response.

Find a Doctor and Get Your Mucosal Barrier Assessed with Lab Testing

Revelations of Research

A study of female monkeys looked at mucosal barrier integrity relative to penetration of HIV into the vaginal mucosal barrier. It showed that HIV could not penetrate a healthy barrier. The mucosal barrier has the ability to defend against the penetration of HIV and virtually any other opportunistic organism.

Another study tested the ability of the mucosal barrier to defend against the aggressive parasite Giardia lamblia. Twelve inmates agreed to drink water loaded with live Giardia organisms. Before they drank the contaminated water, tests were performed to measure their mucosal barrier function.

Nine of the twelve inmates’ secretory IgA levels were found to be below normal—evidence of compromised first-line immunity. The other three had normal levels of secretory IgA and were considered to have healthy first-line immunity. The study sought to determine which, if any, of the inmates would be able to defend against the Giardia without having to be treated with antiparasitic drugs.

All twelve inmates became extremely ill; they suffered severe diarrhea, flu-like symptoms, cramps, and fever. Of the nine who had compromised mucosal barriers on initial testing, not one showed an elevated mucosal immune response to the Giardia. They were immediately treated with appropriate medications. The three inmates with strong mucosal immune responses tested negative and were not administered medications, but were closely monitored. Over the next couple of weeks, researchers watched their secretory levels shift from elevated to normal. These men continued to test negative and were without symptoms for the duration of the trial.

These studies illustrate that a healthy mucosal immune system enables a natural immunological response to defend against potentially pathogenic (disease-causing) organisms.

A Strong First-line Immune Defense: It’s Up to You

Saliva or blood tests can determine the health of an individual’s first-line immune defense. These tests measure secretory IgA levels and reveal antibody levels to specific antigens, providing critical information about the health and function of mucosal barrier immune defense. Although they don’t identify specific infections, they do indicate whether or not an active infection is present. Further testing can identify the specific infectious agent, providing a doctor with the information necessary to direct treatment. Find out more at

In addition to being your primary defense against infections, healthy mucosal immune function can prevent autoimmune disease and support the body’s ability to tolerate our toxic world. Under persistent chronic stress, your mucosal immunity breaks down, placing high demands on your systemic immunity, or backup system. This can then overwhelm your systemic immunity, leaving your entire immune system compromised. The sooner you identify and eliminate the causes of chronic stress, the sooner you can prevent and reverse illnesses, be they clinical or subclinical in source.

FDM providers take a special interest in the immune system’s various components. Factors such as diet, sleep, exercise, attitude, and certainly stress management, all come into play where the foundation of your immunity is concerned. Lab testing and therapeutic nutrients can help you keep it strong.