 |
 |
 |
|
T-cells are white-blood-cells - or lymphocytes - which mature in the thymus. They protect us against invading cells, or antigens. These antigens cause T-cells to become active and produce antibodies. These antibodies stay attached to the cell that created them and the whole antibody-bearing cell attacks the antigens.
T-cells are among the most important cells in the immune system. They originate in the bone marrow and then migrate to the thymus gland (hence the 'T'), where they are trained to respond to a particular target. One T-cell may be subtly altered so that it responds to the polio virus, another to hepatitis-B, a third to the AIDS virus, and so on. Each T-cell has a unique target. When a T-cell leaves the thymus, it goes on the prowl for its enemy. Normally we each have billions of T-cells in our bodies, on the lookout for their individual targets. Once a T-cell spots its enemy, a complex process is set in motion that results in the production of millions of clones. Thus your body can go from having a single scout to well equipped army in a matter of days.
Our bodies produce two main types of T-cells: T-killer cells, which are part of the attack team, and T-helper cells, which direct the whole operation. T-helper cells coordinate other cells in the immune system by producing a family of intercellular signaling substances called 'cytokines'. Each cytokine regulates a different set of cells, suppressing the growth of some and stimulating the growth of others. (Cytokines include the interleukins, interferons, colony-stimulating factors, and tumor necrosis factors.) Without the T-helper cells coordinating the immune system, the battle would be lost. It would be as if you were trying to fight a war when your entire communication network has broken down.
The number of circulating T-cells can give us a clue to the level of an infection. More antigens mean more T-cells.
Causes & Development
Low CD4+ T-cell counts (CD4 counts) are associated with a variety of conditions, including many viral infections, bacterial infections, parasitic infections, sepsis, tuberculosis, coccidioidomycosis, burns, trauma, intravenous injections of foreign proteins, malnutrition, over-exercising, pregnancy, normal daily variation, psychological stress, and social isolation.
The low CD4 counts caused by some of these conditions often fall below 200 per cubic millimeter, which is the level needed to diagnose acquired immunodeficiency syndrome (AIDS) in someone who was previously positive for antibodies to the human immunodeficiency virus (HIV-positive).
Diagnosis & Tests
In addition to the diagnosis of AIDS, CD4 counts are regularly used to make treatment decisions, such as when to start antiretroviral medications and when to begin preventative antibiotics. Because many of the conditions that cause low CD4 counts are common in people diagnosed HIV-positive, caution is advised regarding the use of CD4 counts to make treatment and diagnostic decisions. This is made more urgent since some of the conditions, like psychological stress, are greatly increased when people are told that their CD4 counts are low, which may compound the problem and cause the CD4 count to fall even further. Psychological stress and social isolation are also created by the diagnosis, HIV-positive, and by the diagnosis of AIDS, which may also affect the CD4 count.
|
|
 |
|
 |
Signs, symptoms & indicators of Low T-Helper (CD4) Cell Level:
Risk factors for Low T-Helper (CD4) Cell Level: | | | | | Immunity |  HIV/AIDS | CD4 cells are those cells that are primarily infected with HIV. CD8 cells are those cells that are primarily involved with killing HIV. So as HIV infection progresses, you lose CD4 cells and increase the number of CD8 cells. |
|
| | | | |
Low T-Helper (CD4) Cell Level suggests the following may be present:
Recommendations and treatments for Low T-Helper (CD4) Cell Level: | | | | | Hormone |  DHEA| | One study has found that DHEA therapy (75mg per day) increased CD4 and CD8 cell counts in the majority of HIV patients. [Hasheev, D, et al. Intl AIDS Conference Abstract no PB0322, 1994] |
|
Mineral |
 Zinc| | Low levels of zinc are associated with a drop in T-cell function. |
|
Nutrient |
Alpha Lipoic Acid |
| | | | |
KEY | | Proven definite or direct link | | | May do some good | | | Likely to help |
GLOSSARY
AIDS
Acquired Immune Deficiency Syndrome. An immune system deficiency disorder that suddenly alters the body's ability to defend itself. The AIDS virus invades the T4 helper/inducer lymphocytes and multiplies, causing a breakdown in the body's immune system, eventually leading to overwhelming infection and/or cancer, with ultimate death.
Antibody (Antibodies)
A type of serum protein (globulin) synthesized by white blood cells of the lymphoid type in response to an antigenic (foreign substance) stimulus. Antibodies are complex substances formed to neutralize or destroy these antigens in the blood. Antibody activity normally fights infection but can be damaging in allergies and a group of diseases that are called autoimmune diseases.
Antigen (Antigenic, Antigens)
A substance, usually protein or protein-sugar complex in nature, which, being foreign to the bloodstream or tissues of an animal, stimulates the formation of specific blood serum antibodies and white blood cell activity. Re-exposure to similar antigen will reactivate the white blood cells and antibody programmed against this specific antigen.
Bacteria (Bacterial, Bacterium)
Microscopic germs. Some bacteria are "harmful" and can cause disease, while other "friendly" bacteria protect the body from harmful invading organisms.
CD4
A symbol for glycoprotein expressed on the surface of some lymphocytes, including Helper T-cells. Human CD4 is the receptor that serves as a docking site for HIV viruses on certain lymphocyte cells. Binding of the viral glycoprotein gp120 to CD4 is the first step in viral entry, leading to the fusion of viral and cell membrane. White blood cells are composed primarily of neutrophils, monocytes and lymphocytes. Lymphocytes are either T-cells or B-cells. T-cells (CD3 cells) are divided into T-helper (CD4 cells) and T-suppressor/cytotoxic (CD8 cells) cells.
CD8
White blood cells are composed primarily of neutrophils, monocytes and lymphocytes. Lymphocytes are either T-cells or B-cells. T-cells (CD3 cells) are divided into T-helper (CD4 cells) and T-suppressor/cytotoxic (CD8 cells) cells.
Coccidioidomycosis (Valley Fever)
A disease caused by inhaling spores of the fungus Coccidioides immitis. It starts out as a respiratory illness and may progress to a persistent infection; disseminated coccidioidomycosis is the most severe form and is often fatal. Anyone who is present near dust-producing activities where soil or other materials contaminated with C. immitis are present can get this disease if enough spores are inhaled. Symptoms: First the lungs are infected, possibly producing no symptoms at all or perhaps a fever, chills, and cough. This infection may heal completely, or result in other complications. Approximately 1-in-1000 cases will progress to the disseminated form, leading to lesions in the lung and abscesses throughout the body. These abscesses tend to form in the subcutaneous tissues, skin, bone and the central nervous system (the brain and spinal cord).
Cytokines (Cytokine, TH1, TH2)
Cytokines are chemical messengers that control immune responses. They are secreted by white blood cells, T cells, epithelial cells and some other body cells. There are at least 17 different kinds of interleuken and 3 classes of interferon called alpha, beta and gamma and various subsets. Interleukens and interferons are called “cytokines” and there are two general groupings, Th1 and Th2. Th1 (T-cell Helper type 1) promote cell-mediated immunity (CMI) while Th2 (T-cell Helper type 2) induce humoral immunity (antibodies).
DHEA (DHEA-S)
Dehydroepiandrosterone (DHEA) is a steroid produced by the adrenal glands and is the most abundant one found in humans. DHEA may be transformed into testosterone, estrogen or other steroids. It is found in the body as DHEA or in the sulfated form known as DHEA-S. One form is converted into the other as needed.
Human Immunodeficiency Virus (HIV)
A retrovirus associated with onset of advanced immunodeficiency syndrome (AIDS).
Immune System (Immune Response, Immunity)
A complex that protects the body from disease organisms and other foreign bodies. The system includes the humoral immune response and the cell-mediated response. The immune system also protects the body from invasion by making local barriers and inflammation. The process may involve acquired immunity (the ability to learn and remember a specific infectious agent), or innate immunity (the genetically programmed system of responses that attack, digest, remove, and initiate inflammation and tissue healing).
Milligram (mg, Milligrams)
0.001 or a thousandth of a gram.
Millimeter (Millimeters, mm)
A metric unit of length equaling one thousandth of a meter, or one tenth of a centimeter. There are 25.4 millimeters in one inch.
Necrosis
Death of one or more cells, or of a portion of a tissue or organ.
Parasite (Parasites, Parasitic, Parasitical)
An organism living in or on another organism.
Protein (Proteins)
Compounds composed of hydrogen, oxygen, and nitrogen present in the body and in foods that form complex combinations of amino acids. Protein is essential for life and is used for growth and repair. Foods that supply the body with protein include animal products, grains, legumes, and vegetables. Proteins from animal sources contain the essential amino acids. Proteins are changed to amino acids in the body.
Sepsis (Blood Poisoning, Septicemia)
Like septicemia, an infection that has moved deeply into the body, involving the subcutaneous or submucosal layers, connective tissue, lymph system, or blood. Septicemia: The presence of pathogenic bacteria or other microbes in the blood stream - a serious business, since most defenses are focused outside the bloodstream and the infection has bypassed them either due to its virulence, the depth and severity of the original focal infection or the weakened state of the body's immunity and life energy. Blood poisoning.
Syndrome
A medical condition characterized by a collection of related symptoms (what the patient feels) and signs (what a doctor can observe or measure).
T-Cell (T-Cells)
T cells are lymphocytes that are produced in the bone marrow and mature in the thymus. T cells are responsible for mediating the second branch of the immune system called "cellular immune response." T cells can live for months to years. This lymphocyte population is defined by the presence of a rearranged T-cell receptor.
Thymus (Thymus Gland)
This soft, pinkish-gray gland is tucked behind the sternum between the lungs, shrinks as we come to puberty, and may even atrophy later on. The thymus helps the immune system adapt to various threats. For example, "T" cells are white blood cells that have been activated by the thymus; hence the letter "T". The thymus also produces a number of different compounds that help strengthen the immune system. It increases in size until puberty to approximately 20-50gm and then undergoes progressive atrophy to 5-15gm in older patients. The thymus is the site where bone marrow progenitor cells migrate and differentiate into T-cells. Prothymocytes in the superficial cortex (CD2) give rise to cortical thymocytes (CD1a, CD2, CD3) and CD4 and CD8 (T-helper and -suppressor cells). There are also scattered epithelial cells, macrophages, dendritic cells, and myoid cells. The thymus appears to need plenty of balanced protein, antioxidants like carotenes, vitamin C, E, B6, zinc and selenium.
Tuberculosis
Also known as TB, Consumption or "The White Plague", tuberculosis is an infectious disease caused by a bacterium called Mycobacterium tuberculosis, usually affecting the lungs but possibly also the brain, kidneys and bones. Patients may at first be symptom-free or experience a flu-like illness. In the secondary stage, there might be a slight fever, night sweats, weight loss, fatigue and various other symptoms, depending on the part of the body affected. Tuberculosis of the lung is usually associated with a dry cough that eventually leads to a productive cough with blood-stained sputum. There might also be chest pain and shortness of breath.
Virus (Viri, Viruses)
Any of a vast group of minute structures composed of a protein coat and a core of DNA and/or RNA that reproduces in the cells of the infected host. Capable of infecting all animals and plants, causing devastating disease in immunocompromised individuals. Viruses are not affected by antibiotics, and are completely dependent upon the cells of the infected host for the ability to reproduce.
Zinc
An essential trace mineral. The functions of zinc are enzymatic. There are over 70 metalloenzymes known to require zinc for their functions. The main biochemicals in which zinc has been found to be necessary include: enzymes and enzymatic function, protein synthesis and carbohydrate metabolism. Zinc is a constituent of insulin and male reproductive fluid. Zinc is necessary for the proper metabolism of alcohol, to get rid of the lactic acid that builds up in working muscles and to transfer it to the lungs. Zinc is involved in the health of the immune system, assists vitamin A utilization and is involved in the formation of bone and teeth.
Last updated: Jun 15, 2008
|
 |
|
|
