The Immune System Basic Profile includes tests for the integrity of the endogenous or innate and the adaptive or acquired immune system.
Checking the immune system can help identify the underlying causes of many chronic diseases and clinical disorders, allowing appropriate individualized therapeutic interventions to be designed.
What is the Immune System?
The immune system is an amazing network of cells and proteins that work together harmoniously to protect against infections in the body. These cells and proteins are not a single organ like the heart or liver but are scattered throughout the body to provide a rapid response to potential infections.
The immune system is divided into two major subsystems:
The endogenous or innate immune system
The endogenous or innate immune system is based on cells that do not require additional "training" to do their job. These cells include neutrophils, monocytes, natural killer (NK) cells, and a set of proteins called complement proteins.
Neutrophils: Neutrophils or polymorphonuclear white blood cells are the most common type of white blood cell. They are in the bloodstream and can migrate to the sites of infection within minutes. Neutrophils increase in number during an infection. They are the cells that leave the bloodstream and accumulate in the tissues during the first hours of an infection and are responsible for forming pus. Their primary role is to destroy bacteria and yeast/fungi, while they have very little importance in the defense against viruses.
Monocytes: Monocytes are also found in the bloodstream and makeup 5-10% of white blood cells. When monocytes leave the bloodstream to enter the tissues, they change shape and size and become macrophages. Macrophages are essential for the destruction of yeast/fungi and mycobacteria. T lymphocytes can regulate macrophages and often work with them to destroy microorganisms.
Complement System: The complement system consists of more than 25 blood proteins that work methodically to attack foreign cells and microorganisms. Most of the complement proteins are produced in the liver.
NK Cells: Natural killer (NK) cells are named because they kill virus-infected cells. They are particularly important in defending against herpes viruses such as herpes simplex virus, Epstein-Barr virus, and chickenpox virus (VZV). NK cells are also very important for destroying cancer cells and preventing tumors.
The adaptive or acquired immune system
The adaptive or acquired immune system relies on T-lymphocytes (which help other lymphocytes function or act by destroying other cells) and B-lymphocytes (which produce immunoglobulins or antibodies), two types of cells that require "training" to learn not to attack the cells of our body.
T-lymphocytes: T-lymphocytes, or T-cells, are responsible for cellular immunity. There are two main subpopulations of T-cells: cytotoxic and helper T-cells. In addition, regulatory T-cells play a role in regulating the immune response. Cytotoxic T-cells (CD8) destroy cells infected with viruses (or other pathogens) or cells that have other types of damage or are dysfunctional. Helper T cells (CD4) regulate both endogenous and acquired immune responses.
B-Lymphocytes: B-lymphocytes or B-cells are responsible for humoral immunity, i.e., the production of specific antibodies (immunoglobulins). Antibodies protect the organism in many ways.
Cytokines: Cytokines are a significant group of proteins in the body that serve as hormones and as communication signals between the cells of the immune system. They are produced in response to a threat and represent the communication network between the individual parts of the immune system. In some cases, the immune system cells communicate by direct contact with each other. Still, they often communicate by the secretion of cytokines, which can then act on other cells locally or remotely.
Why is it necessary to check the Immune System?
For the human body to function correctly, it needs an intact immune system that will work in a coordinated and effective way, recognizing and destroying only harmful internal and external invaders (viruses, bacteria, parasites, yeast/fungi, cancer cells). At the same time, this reaction should be limited to be absolutely necessary and not destructive to normal tissues.
In other words, the immune system must be structurally intact and functionally balanced.
- When the immune system is overactive and reacts strongly against internal targets, autoimmunity is created.
- When the immune system is overactive and reacts strongly against external targets, then it develops hypersensitivity (e.g., allergy)
- When the immune system is weak and sluggish and does not react against internal targets, i.e., to recognize and remove tumor cells, cancer is developed.
- When the immune system is weak and sluggish and does not react to external targets, bacteria, viruses, parasites, and yeasts create chronic and recurrent infections.
Although the above conditions seem very different, they have a common denominator, a common underlying mechanism: the dysfunction of the Immune System that eventually leads to a chronic disorder of the body.
What diseases is the Immune System involved in?
Disorders of the human body's defense fall into three categories: immunodeficiencies, autoimmunity, and hypersensitivity.
Immunodeficiencies occur when one or more of the components of the immune system is deficient. The ability of the immune system to respond to pathogens begins to decline after the age of 50 due to immuno-aging. Obesity and malnutrition, low-nutrient diets, alcoholism, and drug use are common causes of immune system dysfunction. In addition, the loss of the thymus gland due to genetic mutations or its surgical removal results in severe immunodeficiency and high susceptibility to infections. Immunodeficiencies can be inherited or acquired. Chronic granulomatous disease is an example of inherited immunodeficiency, and AIDS and certain types of cancer are some causes of acquired immunodeficiency.
Autoimmune disorders involve the other end of the immune system disorders, with overactive immune responses. In this case, the immune system fails to distinguish correctly between self and non-self and attacks parts of the body. Under normal conditions, many of the T lymphocytes and many antibodies react with the antigens of the organism itself. One of the functions of specialized cells (located in the thymus and bone marrow) is to present to new lymphocytes the auto-antigens produced throughout the body and to recognize them, thus preventing autoimmunity.
Hypersensitivity is the immune response that damages the body's tissues. They are divided into four categories (type I - IV) based on the mechanisms involved and the time course of the hypersensitivity reaction. Type I hypersensitivity is an immediate or anaphylactic reaction often associated with allergies. Symptoms can range from mild discomfort to death. Type I hypersensitivity is mediated by IgE antibodies, which trigger mast cells and basophils' degranulation when they bind to an allergen. Type II hypersensitivity occurs when antibodies bind to antigens in the body's cells. It is also called antibody-dependent (or cytotoxic) hypersensitivity and is mediated by IgG and IgM antibodies. When deposited in various tissues, immune complexes (complexes of antigens, complement proteins, and IgG and IgM antibodies) trigger Type III hypersensitivity reactions. Type IV hypersensitivity (cell-mediated or delayed-type hypersensitivity) usually takes two to three days to develop. Type IV reactions are involved in many autoimmune and infectious diseases. T cells, monocytes, and macrophages cause these reactions.
Another vital role of the immune system is to detect and destroy tumors. This is called immune surveillance. Transformed tumor cells express antigens that are not found in normal cells. For the immune system, these antigens appear foreign, and their presence causes the immune system cells to attack the transformed cancer cells. The immune system's primary response to tumors is to destroy abnormal cells using cytotoxic T cells, sometimes with the help of helper T cells. NK cells also similarly kill cancer cells. Some tumors bypass the immune system and eventually become cancers. Some cancer cells release substances that inhibit the normal immune response.
