Autoimmune Diseases (General)

Autoimmune disease (AD) is a condition where the human body's immune system reacts against its own tissues. This process occurs in rheumatoid arthritis (RA), type 1 diabetes, systemic lupus erythematosus (SLE), Crohn's disease, and many other debilitating ailments. Worldwide, autoimmune diseases account for much suffering and morbidity. Many estimates indicate that between 20 to 50 percent of the world's population suffer from some variant of AD. There are too many autoimmune diseases to list here, so a few will be used for illustration.

There is a worldwide distribution of autoimmune conditions and many of the causes and treatments are still unknown. No region, country, race, or gender is invulnerable to AD and the burden of disease falls on all social and economic classes. Although some relationships have been drawn between viral infections, gender, geographic locations, and even diet or occupational exposures, much remains to be seen and understood in the fight against ADs and what must be [Page 193]done to treat them. AD is especially a burden in the developing world as diagnosis and proper treatment often elude those who need them most.

The human body's immune system is able to distinguish self tissues from foreign invading organisms. This is called the self-versus-nonself defense, or immune response. The immune system tissues and cells throughout the body's systems carry markers that enable cells of the immune system to identify these self cells. Cells encountered without markers initiate an immune response and are attacked and eliminated from the human body. This is the process that occurs when an invading organism enters the body. The initiation of this response is called an antigen. Antibodies, such as B cells that will invade and collaborate to kill the attacking bacteria, fungus, or virus, are then formed to continue the response.

AD occurs when the body is unable to properly distinguish self from nonself and initiates a response or an attack that eliminates its own healthy tissues. This attack can be on one organ or on a whole system of organs; for example, with SLE, antibodies are created against the patient's own DNA.

Lymph tissue found in lymph nodes throughout the body, such as the thymus, spleen, and bone marrow, are main centers for immune cells to grow and where signs or symptoms of immune system crisis can usually first be observed. Cells associated with the lymphatic and immune systems travel throughout the body in blood and lymphatic vessels.

Cells that make up the immune system must communicate with one another in order to be able to distinguish which cells are invading and which are not. T cells, B cells, and phagocytes are some major constituents in the immune system. These cells suppress activation of the immune system and maintain immune system homeostasis. T cells are one type of white blood cell that attacks virus-infected cells, foreign cells, and cancer cells. T cells also produce a number of substances that regulate the immune response. Some T cells can seek and destroy invading foreign cells, while some are suppressor T cells. Suppressor T cells slow down and stop the immune response of B cells and other T cells. These suppressor cells effectively “shut off” the antibody production when an infection is under control. When T cells fail or function improperly, AD can result and cells of the immune system attack healthy cells in the body.

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