Autoimmune diseases are the result of the immune system reacting against the body’s own cells. Normally the immune system defends the body against antigens, such as foreign bodies, bacteria or viruses. Sometimes there is a malfunction and the immune system mistakes the body’s own tissues or organs for antigens and attacks them. Nearly any part of the body is susceptible to such an attack.

More than 80 medical conditions may be considered autoimmune diseases. Examples include type 1 diabetes, rheumatoid arthritis, lupus and multiple sclerosis. Autoimmune diseases affect between 14 and 24 million Americans, or up to 8 percent of the population, according to U.S. health agencies. Autoimmune diseases can affect anyone, but many of these conditions are more common in women.

The causes of autoimmune diseases are not completely understood. An inherited link, related to multiple genes, is recognized and is believed to make some people more susceptible to the diseases. However, people with identical genes (such as identical twins) only have a 15 to 50 percent chance of developing the same autoimmune disease (an average of a 30 percent chance). These occurrence rates indicate that some other trigger, such as exposure to an antigen or environmental factors, may activate the disease. Nutrition and hormones are also possibly involved.

With more than 80 possible autoimmune diseases, there are a variety of possible symptoms. Early symptoms are often nonspecific, such as fatigue, dizziness, and joint and muscle pain. In some cases, symptoms occur sporadically, which makes diagnosis difficult. Furthermore, autoimmune diseases may progress unnoticed for years until severe symptoms appear and prompt people to seek medical attention.

There is no known cure for autoimmune diseases. Initial treatment is aimed at repairing or replacing functions lost to tissue damage. In addition, treatment may involve immunosuppressive medications that reduce damage. Whatever treatment is used, it is likely to continue throughout the remainder of the patient’s life, and many side effects of these treatments are possible.

Autoimmune diseases are being studied in many current medical research projects. Topics of study include potential causes, improved diagnostic techniques and new treatment methods. With more advances anticipated in the future, physicians hope to reduce the occurrence and help provide cures for autoimmune diseases.

Autoimmune diseases are medical conditions in which the immune system attacks the body’s own cells and tissues instead of foreign materials and invasive pathogens (disease-causing agents). More than 80 conditions are known or potential autoimmune diseases.

Together, these diseases afflict between 14 and 24 million Americans, according to the National Institutes of Health. Autoimmune disorders may affect between 5 and 8 percent of the U.S. population, according to the Centers for Disease Control and Prevention. However, these conditions appear to be occurring more frequently than in past decades.

The immune system uses antibodies to fight infections. Antibodies are proteins that recognize pathogens such as viruses and bacteria and prevent the invasion and unwanted production of cells. They also help rid the body of toxins and malignant (cancerous) cells. When an unfamiliar antigen (foreign body) enters the body, white blood cells produce antibodies designed specifically to attack it. Other white blood cells known as T cells (T lymphocytes), along with a group of chemicals known as the complement system, work with the antibodies to eliminate the foreign organism.

The immune system also develops the ability to distinguish between the body’s own cells and proteins, and those of antigens. When this normal process is disrupted, the immune system may attack the body’s cells. This process is the basis of autoimmune disease development in humans.

More than 80 diseases have been identified as known or possible autoimmune conditions. They can affect a variety of body systems including the nervous system, glands, digestive tract, kidneys, lungs, blood vessels, sense organs, joints, skin and even hair.

They can range from causing no symptoms to the presence of severely debilitating symptoms. Autoimmune diseases may cause injury to a single organ or tissue type, or the immune response can cause widespread injury to multiple organs or tissues.

Common examples of recognized autoimmune diseases include:

• Rheumatoid arthritis and juvenile rheumatoid arthritis
  
  
• Type 1 diabetes and a variation called latent autoimmune diabetes of adulthood
  
  
•  Hashimoto’s thyroiditis and Graves' disease
  
  
• Multiple sclerosis
  
  
• Systemic lupus erythematosus and some other forms of lupus
  
  
• Pernicious anemia
  
  
• Vitiligo
  
  
• Sjogren’s syndrome
  
  
• Alopecia areata (patchy baldness)
  
  

• Celiac disease (gluten intolerance)
  
  

• Autoimmune hepatitis
  
  

• Autoimmune glomerulonephritis (kidney disease)

Less-common autoimmune diseases include:

Conditions in which autoimmunity may play a role include:

• Crohn’s disease and ulcerative colitis
• Psoriasis and psoriatic arthritis
• Polymyalgia rheumatica
• Temporal arteritis
• Sarcoidosis

Conditions that have some features in common to many autoimmune diseases but are generally believed to be due to other factors include fibromyalgia and chronic fatigue syndrome. In addition, there are many immune disorders that do not involve autoimmunity, ranging from allergies to HIV/AIDS.

Women are more susceptible than men to most autoimmune diseases. Some studies estimate that as many as 75 percent of patients with an autoimmune disease are women. When all of these types of diseases are grouped together, deaths from autoimmune diseases are among the top 10 causes of death for women under the age of 65.

However, the prevalence of specific autoimmune diseases varies by sex. More than 85 percent of patients with thyroiditis, scleroderma and lupus are women. In contrast, type 1 diabetes occurs in both sexes at about the same rate.

Autoimmune diseases can affect all races and ethnic groups, but the prevalence varies according to the specific condition.

The causes of autoimmune diseases are not completely understood. Many years of scientific research have focused on the role of the immune system in initiating an attack on the body’s own cells. The results appear to indicate that autoimmune diseases result from a combination of factors.

Genetics play a major role in the development of certain autoimmune diseases. For type 1 diabetes, as well as other autoimmune diseases, an increased risk is seen in certain families. For example, identical twins share the same genes. Thus, when one twin has an autoimmune disease, the other twin has a 15 to 50 percent chance of developing the same disease (an average of a 30 percent chance). In comparison, non-identical twins and other siblings have a 2 to 5 percent chance of developing the disease.

Researchers are exploring which genes may be responsible for autoimmune diseases. The majority of autoimmune disease appear to result from the effects of multiple genes acting together to disrupt immune system function. In addition, an individual with one autoimmune disease has an increased risk of developing another. This may mean that some of the genetic mechanisms that increase a person’s susceptibility are common to multiple autoimmune diseases.

Genetics is not the only contributor to the development of autoimmune diseases – exposure to toxins and environmental factors are also important. There is evidence that certain medications, heavy metals, other pollutants and ultraviolet light from the sun may have a role. Deficiencies in micronutrients such as antioxidants and the mineral selenium may also contribute.

Scientific evidence indicates that many autoimmune diseases can be triggered by a preceding infection. For example, the Epstein-Barr, rubella and mumps viruses are among the infectious diseases that have all been implicated in the development of autoimmune diseases in some people. These and other infectious antigens may resemble proteins of normal body cells. After the immune system fights these viral infections, it may mistake the healthy body cells for the antigens.

The signs and symptoms of autoimmune diseases vary widely depending on the specific disease. Autoimmune diseases often result in body tissues being destroyed, an organ experiencing abnormal growth or changes in organ function. Additionally, these signs can develop in one or multiple tissues and organs.

Common targets of autoimmune attacks include red blood cells, blood vessels, connective tissues, endocrine glands, muscles, joints and skin. In type 1 diabetes, the target is the endocrine glands and specifically the pancreas.

Nonspecific symptoms that are associated with a number of autoimmune diseases include:

• Fatigue
• Dizziness
• Joint and muscle pain
• Fever
• Difficulty concentrating
• Skin problems
• Unexplained weight loss or gain

Some symptoms occur in certain patterns. Patients may experience attacks followed by remission. During times of remission, patients may feel that the condition has resolved, only to experience additional attacks later.

Autoimmune diseases can be difficult to diagnose during the early stages of disease. How difficult the specific diagnosis is will depend on the type of autoimmune disease and the symptoms experienced by the patient, which may come and go. In other instances, the disease may progress unnoticed for some time.

For example, people with type 1 diabetes may not recognize early warning signs, such as excessive thirst or unexplained weight loss. For some individuals, the condition may not be diagnosed until a severe complication, such as ketoacidosis, occurs and results in the need for immediate medical attention.

In most cases, a physician’s diagnosis will rely on the patient’s medical history, a physical examination and medical testing. In compiling the medical history, a physician may ask about the symptoms the patient is experiencing, whether there are any patterns of their occurrence, triggering incidents or other contributing factors.

Patients may wish to keep a symptoms list or diary of when symptoms occur and any groups of symptoms that are experienced together. Patients should share this list with their physician, as well inform the physician of any family members with similar symptoms or other autoimmune diseases.

No single diagnostic test can detect an autoimmune disease. Autoantibody blood tests may identify the misguided antibodies that attack healthy body cells. These tests may also be used to rule out other possible causes of a patient’s symptoms.

No definitive diagnosis criteria are available for many of the autoimmune diseases. Instead, numerous consultations with medical specialists and tests performed over months to years may be necessary to determine the presence of such a disorder.

For some autoimmune disorders, people with known risk factors such as family history may be advised by their physician to undergo genetic tests or regular screening tests, such as thyroid blood tests or glucose tests.

No cure for autoimmune diseases is available. Instead, initial treatment focuses on replacing or repairing organ function and restoring normal metabolic function as much as possible.

For example, a physician may recommend augmenting missing or depleted hormones or other substances that the affected organ or tissue normally produces. This could mean blood transfusions, thyroid medications, vitamins or other dietary supplements. For type 1 diabetes, patients will require insulin therapy to control glucose (blood sugar) levels and prevent complications.

Treatment may involve using immunosuppressives such as corticosteroids or disease-modifying antirheumatic drugs(DMARDs). Immunosuppressives reduce the immune system’s ability to produce antibodies, which reduces the damage they can cause to body tissues. This treatment has many possible negative side effects, including reducing the body’s ability to respond normally to infections. Other possible side effects from long-term use of  corticosteroids may include secondary diabetes, osteoporosis, fractures, glaucoma and cataracts.

Transplanting a viable organ or functioning cells may also help treat certain autoimmune diseases that affect a single organ, such as a kidney transplant for severe glomerulonephritis or a pancreas transplant or islet cell transplant for autoimmune diabetes. However, the new tissue is still susceptible to the immune response that damaged the original one.

Specific treatment for any autoimmune disease will be determined by a physician based on the patient’s:

• Age, general health status and medical history
• Extent of the disease
• Tolerance for specific therapies
• Expectations for the course of the disease
• Personal opinion or preference

Continuous treatment for autoimmune diseases is necessary for the remainder of the patient’s life. Regular consultations with a specialist physician are typically recommended to monitor the treatment and to help prevent complications.

Although environmental factors may play a role in the development of an autoimmune disease, patients apparently must first be genetically susceptible to the condition. Thus, for most autoimmune disorders, prevention may not be currently possible.

A significant amount of research is being conducted on autoimmune diseases, and clinical research studies into autoimmune diseases are receiving more attention than in times past. Much of this research is focused on better understanding the diseases and their causes.

Scientists anticipate that identifying potential disease triggers will allow the development of methods to prevent autoimmune diseases. The potential roles of pollutants, such as exposure to PCBs (polychlorinated biphenyls), heavy metals, pesticides, dioxins and hormonal compounds, are among the possible causes being explored.

Research is also under way to improve diagnostic abilities. This includes refining genetic tests and improving autoantibody testing to identify specific antibodies that attack certain cells in the body.

Physicians are also working to develop definitive diagnostic criteria for use in identifying additional specific types of autoimmune disease. With these criteria, it may be possible to provide more rapid diagnosis, start treatment sooner, reduce disease damage or its progression, and address patients’ frustration.

New treatment methods for autoimmune diseases are also being developed. One goal is the development of focused immunosuppressives that could reduce the negative side effects of certain medications. Scientists are trying to decrease the need for immunosuppressives after an islet cell transplant or organ transplant. Gene therapy is also being studied as a means to replace the function of damaged tissues and reduce the autoimmune response.

Preparing questions in advance can help patients have more meaningful discussions with healthcare professionals regarding their conditions. Patients may wish to ask their doctor the following questions about autoimmune diseases:

1. Why do you think I may have an autoimmune disease?
   
   
2. What type of autoimmune disease might I have?
   
   
3. Are there other possible causes of my symptoms?
   
   
4. What is a symptom diary? Should I keep one?
   
   
5. What screening or diagnostic tests are recommended for me? Do I need to do anything to prepare for them?
   
   
6. What do my tests indicate? Are they definitive, or do I need more tests?
   
   
7. How is my condition treated?
   
   
8. What are the benefits of treatment for me? What are the risks?
   
   
9. Do I have any alternatives?
   
   
10. Are my family members also susceptible to the disease? Should they have any tests?
    
    
11. Will my disease get worse over time?
    
    
12. Do I need to make lifestyle changes to cope with this disease?
    
    
13. Do you recommend that I consult a specialist in autoimmune diseases or my specific condition?