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Systemic lupus erythematosus (SLE) is a chronic, often life-long, autoimmune disease. It can be mild to severe, and affects mostly women. SLE may affect various parts of the body, but it most often manifests in the skin, joints, blood, and kidneys. SLE was first described in 1828. Its very name helps define the disease:
Systemic is used because the disease can affect organs and tissue throughout the body.
Lupus is Latin for wolf. It refers to the rash that extends across the bridge of the nose and upper cheekbones and was thought to resemble a wolf bite.
Erythematosus is from the Greek word for red and refers to the color of the rash..
Lupus has many different symptomsn ones include:
Fatigue
Joint pain or swelling
Skin rashes
CAUSES/RISK FACTORS FOR LUPUS
Systemic lupus erythematosus is a complex disorder that most likely results from a combination of processes and factors.
Environmental factors, such as viruses, exposure to chemicals, or sunlight, trigger inflammatory or immune activity. This immune activation may begin as an appropriate response to an unwanted "invader." But, because of a combination of genetic factors, an individual with lupus develops an ongoing immune response that does not shut itself off appropriately. This leads to waxing and waning flares of inflammation that can involve various organs of the body, depending on specific features of this self-perpetuating immune response in individual patients.
The exact combination of genes that predispose individuals to SLE may differ somewhat from patient to patient, but probably share certain common features which tend to impair the ability of the body to get rid of immune-triggering particles and which tend to prolong or increase the degree of immune responsiveness to these triggers.
A major characteristic of lupus is that it is an autoimmune response in which immune factors, called autoantibodies, attack the person's own cells. Some autoantibodies are normal in a well-balanced immune system, and serve various roles to help the body dispose of wastes, protect from infectious invaders, and to keep blood vessels clear. In healthy people, autoantibodies tend to be well-regulated and well "masked," or covered up, until needed. Therefore, it is probably the high activity and high detestability of autoantibodies that makes lupus unique, not the fact that they exist.
THE INFLAMMATORY PROCESS AND AUTOIMMUNITY
The Normal Immune System Response. The inflammatory process is a byproduct of the activity of the body's immune system, which fights infection and heals wounds and injuries:
When an injury or an infection occurs, white blood cells are mobilized to rid the body of any foreign proteins, such as a virus.
The masses of blood cells that gather at the injured or infected site produce factors to fight any infections.
In the process, the surrounding area becomes inflamed and some healthy tissue is injured. The immune system is then called upon to repair wounds by clotting any bleeding blood vessels and initiating fiber-like patches to the tissue.
Under normal conditions, the immune system has special factors that control and limit this inflammatory process.
The Infection Fighters. B cells and T cells are two important components of the immune system that play a role in the inflammation associated with lupus. Both B cells and T cells belong to a family of immune cells called lymphocytes. Lymphocytes help fight infection.
B cells and T cells are involved in the immune system's response to infection. Antigens are foreign bodies (such as bacteria and viruses) that stimulate the immune system to produce autoantibodies. When a T cell recognizes an antigen it will produce chemicals (cytokines) that cause B cells to multiply and release many immune proteins (antibodies). These antibodies circulate widely in the bloodstream, recognizing the foreign particles and triggering inflammation in order to rid the body of the invasion.
An antigen is a substance that can provoke an immune response. Typically antigens are substances not usually found in the body.
For reasons that are still not completely understood, both the T cells and B cells become overactive in lupus patients. In lupus, a complex interaction between activated immune cells and an impaired antigen-elimination process leads to a greater than normal range of what the antibodies recognize. Eventually, antibodies are made that recognize more of the body's own tissues in a stronger or more persistent manner than is healthy, and inflammatory responses are mounted in these tissues.
Autoantibodies. In the majority of patients with SLE, antinuclear antibodies (ANA) are detectable. Such autoantibodies may be present in individuals up to 7 years prior to their developing symptoms of lupus. Some subtypes of ANA are found in lupus patients and only rarely in people without lupus. These include:
Anti-ds DNA. An autoantibody called anti-double stranded DNA (anti-ds DNA) may play an important role in some lupus patients.
Anti-Sm antibodies. This antibody is found most often in lupus patients of African descent and is almost never detected in people without lupus.
Anti-Ro (SSA) and Anti-La (SSB)
Antiphospholipid antibodies
Cytokines. Most immune cells secrete or stimulate the production of powerful immune factors called cytokines. In small amounts, cytokines are indispensable for maintaining the balance of the body during immune responses, including:
Infections
Injuries
Tissue repair
Blood clotting
Clearing of debris from inflamed blood vessels
Other aspects of healing.
If overproduced, however, they can cause serious damage, including dangerous levels of inflammation and cellular injury. Specific cytokines called interferons and interleukins play a critical role in SLE by regulating the secretion of autoantibodies by B cells.
Complement. Another immune factor of high interest in SLE is the complement system. This is comprised of more than 30 proteins and is important for defending and regulating the immune response. Inherited deficiencies in certain complement components (C1q, C1r, C1s, C4, and C2) have long been associated with SLE.
GENETIC FACTORS
SLE is a complex disorder and researchers are still in the early stages of unraveling how genetic factors may alter and affect the immune system. Researchers estimate that 20 - 100 different genetic factors may make a person susceptible to SLE.
RISK FACTORS
The number of people diagnosed with lupus has more than tripled over the past four decades. This may simply indicate a greater degree of doctor training in recognizing the syndrome. GENDER About 90% of lupus patients are women, most diagnosed when they are in their childbearing ages. Hormones may be an explanation. After menopause, women are only 2.5 times as likely as men to contract SLE. Flares also become somewhat less common after menopause in women who have chronic SLE.
ETHNICITY
African-Americans are three to four times more likely to develop the disease than Caucasians and to have severe complications. Hispanics and Asians are also more susceptible to the disease.
FAMILY HISTORY
A family history plays a strong role in SLE. A brother or sister of a patient with the disorder has 20 times the risk as someone without an immediate family member with SLE.
RISK FACTORS IN CHILDREN
The disease is rare in childhood. When it does occur, it is often associated with thrombotic thrombocytopenia purpura, a condition resulting from abnormally low levels of blood platelets. SLE in children may also be caused by certain medications, including minocycline and zafirlukast.
PRESENCE OF OTHER AUTOIMMUNE DISORDERS
Rheumatoid Arthritis. Studies have investigated the relationship among hormones, SLE, and rheumatoid arthritis, another autoimmune disease. Higher levels of estrogen are associated with SLE, while lower levels are associated with rheumatoid arthritis. Some research suggests that some patients, in fact, progress from one disease to the other, and that such transitions occur during major hormonal shifts, such as the onset of menopause or pregnancy. Rheumatoid arthritis is a systemic autoimmune disease that initially attacks the lining, or synovium, of the joints.
DRUG-INDUCED LUPUS
Many prescription drugs can cause lupus-like skin symptoms. These include high blood pressure (hypertension) medications, including hydrochlorothiazide, angiotensin-converting-enzyme inhibitors, and calcium-channel blockers. About 40 different drugs have been linked to lupus onset. Anyone diagnosed with cutaneous lupus erythematosus should be sure to tell their doctors all the medications (including herbs and supplements) that they are taking.
LIFESTYLE FACTORS
Smoking. Smoking may be a risk factor for triggering SLE and can increase the risk for skin and kidney problems in women who have the disease.
POSSIBLE SLE TRIGGERS
In genetically susceptible people, there are various external factors that can provoke an immune response. Possible SLE triggers include colds, fatigue, stress, chemicals, sunlight, and certain drugs.
Viruses. Patients with SLE may be more likely to have been exposed to certain viruses than the general population. These viruses include the Epstein-Barr virus (the cause of mononucleosis), cytomegalovirus, and parvovirus-B1. In particular, some research suggests a strong association between Epstein-Barr virus (EBV) and increased risk of lupus, particularly for African-Americans.
Sunlight. Ultraviolet (UV) rays found in sunlight are important SLE triggers. When they bombard the skin, they can alter the structure of DNA in cells below the surface. The immune system may perceive these altered skin cells as foreign and trigger an autoimmune response against them. UV light is categorized as UVB or UVA depending on the length of the wave. Shorter UVB wavelengths cause the most harm.
Chemicals. Clusters of SLE cases have occurred in populations with high exposure to certain chemicals. Chlorinated pesticides and crystalline silica are two suspects. A number of other chemicals are under investigation. However, it is very difficult to determine a causal role for any specific chemicals. (Silicone breast implants have been under intense scrutiny as a possible trigger of autoimmune diseases, including SLE. The weight of evidence to date, however, finds no support for this concern.) Some drugs have been associated with a temporary lupus syndrome (drug-induced lupus), which resolves when these drugs are stopped.
Hormones. Cytokines, major immune factors that are active in SLE, are directly affected by sex hormones. In general, estrogen enhances antibody production, and testosterone reduces antibody production, although their exact role in SLE may be more complicated than that since there are various ways in which each hormone might influence various immune cells. Women with SLE may have lower levels of several active male hormones (androgens), and some men who are affected by SLE may also have abnormal androgen levels. Premature menopause, and its accompanying symptoms (such as hot flashes), is common in women with SLE. Hormone replacement therapy (HRT), which is used to relieve these symptoms, increases the risk for blood clots and heart problems. It is not clear whether HRT triggers SLE flares. Women should discuss with their doctors whether HRT is an appropriate and safe choice. Guidelines recommend that women who take HRT use the lowest possible dose for the shortest possible time. Women with SLE who have active disease, antiphospholipid antibodies, or a history of blood clots or heart disease should not use HRT.
Oral Contraceptives. Female patients with lupus used to be cautioned against taking oral contraceptives (OCs) due to the possibility that estrogen could trigger lupus flare-ups. However, recent evidence indicates that OCs are safe, at least for women with inactive or stable lupus. Women who have been newly diagnosed with lupus should avoid OCs. Lupus can cause complications in its early stages. For this reason, women should wait until the disease reaches a stable state before taking OCs. In addition, women who have a history of, or who are at high risk for, blood clots (particularly women with antiphospholipid syndrome) should not use OCs. The estrogen in OCs increases the risk for blood clots.
Sources: lupus.org, rheumatology.org, hopkinslupus, hss.edu
The number of people diagnosed with lupus has more than tripled over the past four decades. This may simply indicate a greater degree of doctor training in recognizing the syndrome. GENDER About 90% of lupus patients are women, most diagnosed when they are in their childbearing ages. Hormones may be an explanation. After menopause, women are only 2.5 times as likely as men to contract SLE. Flares also become somewhat less common after menopause in women who have chronic SLE.
ETHNICITY
African-Americans are three to four times more likely to develop the disease than Caucasians and to have severe complications. Hispanics and Asians are also more susceptible to the disease.
FAMILY HISTORY
A family history plays a strong role in SLE. A brother or sister of a patient with the disorder has 20 times the risk as someone without an immediate family member with SLE.
RISK FACTORS IN CHILDREN
The disease is rare in childhood. When it does occur, it is often associated with thrombotic thrombocytopenia purpura, a condition resulting from abnormally low levels of blood platelets. SLE in children may also be caused by certain medications, including minocycline and zafirlukast.
PRESENCE OF OTHER AUTOIMMUNE DISORDERS
Rheumatoid Arthritis. Studies have investigated the relationship among hormones, SLE, and rheumatoid arthritis, another autoimmune disease. Higher levels of estrogen are associated with SLE, while lower levels are associated with rheumatoid arthritis. Some research suggests that some patients, in fact, progress from one disease to the other, and that such transitions occur during major hormonal shifts, such as the onset of menopause or pregnancy. Rheumatoid arthritis is a systemic autoimmune disease that initially attacks the lining, or synovium, of the joints.
DRUG-INDUCED LUPUS
Many prescription drugs can cause lupus-like skin symptoms. These include high blood pressure (hypertension) medications, including hydrochlorothiazide, angiotensin-converting-enzyme inhibitors, and calcium-channel blockers. About 40 different drugs have been linked to lupus onset. Anyone diagnosed with cutaneous lupus erythematosus should be sure to tell their doctors all the medications (including herbs and supplements) that they are taking.
LIFESTYLE FACTORS
Smoking. Smoking may be a risk factor for triggering SLE and can increase the risk for skin and kidney problems in women who have the disease.
POSSIBLE SLE TRIGGERS
In genetically susceptible people, there are various external factors that can provoke an immune response. Possible SLE triggers include colds, fatigue, stress, chemicals, sunlight, and certain drugs.
Viruses. Patients with SLE may be more likely to have been exposed to certain viruses than the general population. These viruses include the Epstein-Barr virus (the cause of mononucleosis), cytomegalovirus, and parvovirus-B1. In particular, some research suggests a strong association between Epstein-Barr virus (EBV) and increased risk of lupus, particularly for African-Americans.
Sunlight. Ultraviolet (UV) rays found in sunlight are important SLE triggers. When they bombard the skin, they can alter the structure of DNA in cells below the surface. The immune system may perceive these altered skin cells as foreign and trigger an autoimmune response against them. UV light is categorized as UVB or UVA depending on the length of the wave. Shorter UVB wavelengths cause the most harm.
Chemicals. Clusters of SLE cases have occurred in populations with high exposure to certain chemicals. Chlorinated pesticides and crystalline silica are two suspects. A number of other chemicals are under investigation. However, it is very difficult to determine a causal role for any specific chemicals. (Silicone breast implants have been under intense scrutiny as a possible trigger of autoimmune diseases, including SLE. The weight of evidence to date, however, finds no support for this concern.) Some drugs have been associated with a temporary lupus syndrome (drug-induced lupus), which resolves when these drugs are stopped.
Hormones. Cytokines, major immune factors that are active in SLE, are directly affected by sex hormones. In general, estrogen enhances antibody production, and testosterone reduces antibody production, although their exact role in SLE may be more complicated than that since there are various ways in which each hormone might influence various immune cells. Women with SLE may have lower levels of several active male hormones (androgens), and some men who are affected by SLE may also have abnormal androgen levels. Premature menopause, and its accompanying symptoms (such as hot flashes), is common in women with SLE. Hormone replacement therapy (HRT), which is used to relieve these symptoms, increases the risk for blood clots and heart problems. It is not clear whether HRT triggers SLE flares. Women should discuss with their doctors whether HRT is an appropriate and safe choice. Guidelines recommend that women who take HRT use the lowest possible dose for the shortest possible time. Women with SLE who have active disease, antiphospholipid antibodies, or a history of blood clots or heart disease should not use HRT.
Oral Contraceptives. Female patients with lupus used to be cautioned against taking oral contraceptives (OCs) due to the possibility that estrogen could trigger lupus flare-ups. However, recent evidence indicates that OCs are safe, at least for women with inactive or stable lupus. Women who have been newly diagnosed with lupus should avoid OCs. Lupus can cause complications in its early stages. For this reason, women should wait until the disease reaches a stable state before taking OCs. In addition, women who have a history of, or who are at high risk for, blood clots (particularly women with antiphospholipid syndrome) should not use OCs. The estrogen in OCs increases the risk for blood clots.
Sources: lupus.org, rheumatology.org, hopkinslupus, hss.edu
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