Autoimmune disease is a disorder of the immune system in which autoantibodies and/or effector lymphocytes attack cells and tissues of the organism mounting the immune response. It is a failure of immunological tolerance to self. The sequence of events leads to tissue damage and destruction as well as other features of the disease process. For the purpose of this discussion the organism is a human being. Although autoimmune disease can occur in other higher forms of life, it is a disease of the adaptive immune system. As such, it does not occur in lower forms of life that only have an innate immune system.
Diseases of autoimmunity can affect any of the organ systems of the body. Some diseases affect one type of tissue in one organ system. Others affect multiple types of tissues within an organ system. Yet, others produce disease in multiple different organ systems. Lupus (SLE) is the prototype of the latter.
The actual cause of autoimmune diseases is unknown. But, researchers believe it to involve a combination of environmental and genetic factors. In general terms, the inflammation and other aspects of the immune response which normally provide defense against pathogens, end up being against self instead. The end result is disease in the tissues affected.
There are two ways that the immune system can initiate disease in tissues. The most common way is by producing autoantibodies which bind directly to antigens of affected tissues. The other way is by producing immune complexes which deposit in tissues and cause indirect damage. The latter mechanism is most common when the disease involves the kidneys or is associated with vasculitis. With vasculitis the clusters of antigens and autoantibodies deposit in the blood vessels.
Some of the more common autoimmune disorders are the following:
- Addison’s disease
- Celiac disease
- Graves’ disease
- Hashimoto’s thyroiditis
- Multiple sclerosis
- Pernicious anemia
- Rheumatoid arthritis
- Sjogren’s syndrome
- Systemic lupus erythematosus (Lupus)
- Type 1 diabetes
Advanced knowledge of the pathophysiology is greater for some autoimmune diseases than others. But further increases are the key to understanding the cause. Acquaintance with the terms in regard to it is the basis for that understanding.
Acetylcholine receptor antibody – Is an autoantibody usually present in the blood of individuals with myasthenia gravis. The antibodies cause damage to the acetylcholine receptors at the neuromuscular plate of skeletal muscles. The result is an interruption in the transmission of signals from the nerve endings to the muscles. A blood test can detect this abnormal protein.
Anti-cyclic citrullinated peptide (CCP) antibody (Anti-CCP) – An antibody which binds to citrulline – an amino acid formed from the conversion of a parent amino acid – arginine. It is positive in many patients with rheumatoid arthritis (RA) and correlates more with RA than the rheumatoid factor.
Antinuclear antibody (ANA) – Is an autoantibody directed against structures within the nucleus of a cell. An ANA panel is a blood test for antinuclear antibodies. It is oftentimes positive in a variety of autoimmune diseases. A positive test is more significant, the higher the titer. It is more specific for lupus if antibodies against double-stranded DNA are also present.
Anti-inflammatory medication – Is any of a group of medicines which suppresses inflammation. More specifically, nonsteroidal anti-inflammatory drugs (NSAIDs) are a group of medicines in the aspirin family which suppress inflammation and pain. Some require prescription. Others are available over-the-counter. Their use is in the treatment of some of the autoimmune diseases as well as the pain and inflammation associated with other diseases.
Antimalarial medications – Is a group of medications normally used to treat malaria which is also effective in treating rheumatoid arthritis. The main one is hydroxychloroquine. Its branded name is Plaquenil.
Biologic agents – Are a group of drugs used to treat rheumatoid arthritis that affect various parts of the immune defense system that play a role in the disease process. Their use is generally when other medications have failed. The different classes are as follows:
Collagen vascular disease –Is an autoimmune disease that affects collagen and blood vessels of the body. More specifically, it is a connective tissue disease with vasculitis. Lupus and scleroderma are two of the more common ones.
Connective tissue disease – It is a disease affecting collagen or other core components of connective tissue. It is usually but not always the result of autoimmunity. There are some rare inherited forms. Synonymous use of the term with collagen vascular disease is not uncommon. But in the truest sense of the terms there is a difference. It is the involvement of blood vessels in the case of collagen vascular disease. Ergo, collagen vascular disease is connective tissue disease, but the converse is not always the case.
Corticosteroids – Are the man-made equivalents of glucocorticoid hormones which the adrenal glands produce. Their use is in the treatment of inflammation and other signs and symptoms of autoimmune and some other diseases.
Disease modifying anti-rheumatic drugs (DMARDs) – Is a class of medications for treating rheumatoid arthritis which have the ability to modify the course of the disease as opposed to simply treating pain and inflammation like the NSAIDS. Agents in this group include the following:
HLA-B27 antigen – Is a protein on the surface of white blood cells of some individuals. It is detectable by a blood test. When present it is indicative of a greater than average risk of developing or having certain autoimmune diseases, particularly anklylosing spondylitis.
Immune complex – Is an interlocking cluster of antibodies and antigens which form a network. They form deposits in tissues, particularly blood vessels, the inner lining of the heart, nerves and kidneys. There are various theories of how the process begins. But the complex activates various aspects of the immune system, often including complement. The resulting inflammation and other immune system events cause the tissue damage and resultant disease. The source of the antigens forming the complex can be natural body tissues or foreign particles.
Immunosuppressive –Is a treatment agent which suppresses or prevents a response of the immune system. It is a subclass of disease modifying drug for the treatment of autoimmune disease. Its use is also in the area of organ and tissue transplantation to prevent rejection.
Monoclonal antibodies – Are antibodies produced by identical cells of the immune system which originate from the same parent cell. They are laboratory engineered to act against specific parts and actions of the immune system. Therefore they are one of the more specific and sophisticated biologic agents for treating autoimmune disease.
Nucleus – The central part of a cell that contains it DNA or genetic code. – Nuclear – adj.
Rheumatoid factor – Is an auto antibody often present in rheumatoid arthritis. It reacts against IgG immunoglobulins. A blood test can detect it. The test is often but not always positive in rheumatoid arthritis.
Vasculitis – Is inflammation of blood vessels. The distribution of involvement varies depending upon the disease. The cause is usually unknown. But it is often a feature of autoimmune disease.