Lupus erythematosus | |
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Classification and external resources | |
Artist's depiction of woman with typical Lupus malar rash (‘butterfly’ rash).[1] |
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ICD-10 | L93., M32. |
ICD-9 | 710.0 |
OMIM | 152700 |
DiseasesDB | 12782 |
MedlinePlus | 000435 |
eMedicine | med/2228 emerg/564 |
MeSH | D008180 |
Systemic lupus erythematosus (pronounced /sɨˈstɛmɨk ˈluːpəs ˌɛrɨˌθiːməˈtoʊsəs/ ( listen), often abbreviated to SLE or lupus, is a chronic systemic autoimmune disease (or autoimmune connective tissue disease) that can affect any part of the body. As occurs in other autoimmune diseases, the immune system attacks the body’s cells and tissue, resulting in inflammation and tissue damage.[2]
SLE most often harms the heart, joints, skin, lungs, blood vessels, liver, kidneys, and nervous system. The course of the disease is unpredictable, with periods of illness (called flares) alternating with remissions. The disease occurs nine times more often in women than in men, especially between the ages of 15 and 50, and is more common in those of non-European descent.[3][4][5]
SLE is treatable through addressing its symptoms, mainly with cyclophosphamides, corticosteroids and immunosuppressants; there is currently no cure. SLE can be fatal, although with recent medical advances, fatalities are becoming increasingly rare. Survival for people with SLE in the United States, Canada, and Europe is approximately 95% at five years, 90% at 10 years, and 78% at 20 years.[5]
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SLE is one of several diseases known as "the great imitators" because it often mimics or is mistaken for other illnesses.[7] SLE is a classical item in differential diagnosis,[3] because SLE symptoms vary widely and come and go unpredictably. Diagnosis can thus be elusive, with some people suffering unexplained symptoms of untreated SLE for years.
Common initial and chronic complaints include fever, malaise, joint pains, myalgias, fatigue, and temporary loss of cognitive abilities. Because they are so often seen with other diseases, these signs and symptoms are not part of the diagnostic criteria for SLE. When occurring in conjunction with other signs and symptoms (see below), however, they are considered suggestive.[8]
As many as 30% of sufferers have some dermatological symptoms (and 65% suffer such symptoms at some point), with 30% to 50% suffering from the classic malar rash (or butterfly rash) associated with the disease. Some may exhibit thick, red scaly patches on the skin (referred to as discoid lupus). Alopecia; mouth, nasal, and vaginal ulcers; and lesions on the skin are also possible manifestations.
The most commonly sought medical attention is for joint pain, with the small joints of the hand and wrist usually affected, although all joints are at risk. The Lupus Foundation of America estimates that more than 90 percent of those affected will experience joint and/or muscle pain at some time during the course of their illness.[9] Unlike rheumatoid arthritis, lupus arthritis is less disabling and usually does not cause severe destruction of the joints. Fewer than ten percent of people with lupus arthritis will develop deformities of the hands and feet.[9] SLE patients are at particular risk of developing osteoarticular tuberculosis.[10]
It is suggested that there might be an association between rheumatoid arthritis and SLE,[11] and that SLE is associated with an increased risk of bone fractures in relatively young women.[12]
Anaemia and other iron deficiencies may develop in up to 50% of cases. Low platelet and white blood cell counts may be due to the disease or a side-effect of pharmacological treatment. People with SLE may have an association with antiphospholipid antibody syndrome[13] (a thrombotic disorder), wherein autoantibodies to phospholipids are present in their serum. Abnormalities associated with antiphospholipid antibody syndrome include a paradoxical prolonged PTT Partial thromboplastin time (which usually occurs in hemorrhagic disorders) and a positive test for antiphospholipid antibodies; the combination of such findings have earned the term lupus anticoagulant-positive. Another autoantibody finding in SLE is the anticardiolipin antibody, which can cause a false positive test for syphilis.
A person with SLE may have inflammation of various parts of the heart, such as pericarditis, myocarditis, and endocarditis. The endocarditis of SLE is characteristically noninfective (Libman-Sacks endocarditis) and involves either the mitral valve or the tricuspid valve. Atherosclerosis also tends to occur more often and advances more rapidly than in the general population.[14][15][16]
Lung and pleura inflammation can cause pleuritis, pleural effusion, lupus pneumonitis, chronic diffuse interstitial lung disease, pulmonary hypertension, pulmonary emboli, pulmonary hemorrhage, and shrinking lung syndrome.
Painless hematuria or proteinuria may often be the only presenting renal symptom. Acute or chronic renal impairment may develop with lupus nephritis, leading to acute or end-stage renal failure. Because of early recognition and management of SLE, end-stage renal failure occurs in less than 5% of cases.
A histological hallmark of SLE is membranous glomerulonephritis with "wire loop" abnormalities.[17] This finding is due to immune complex deposition along the glomerular basement membrane, leading to a typical granular appearance in immunofluorescence testing.
Neuropsychiatric syndromes can result when SLE affects the central or peripheral nervous system. The American College of Rheumatology defines 19 neuropsychiatric syndromes in systemic lupus erythematosus.[18] The diagnosis of neuropsychiatric syndromes concurrent with SLE is one of the most difficult challenges in medicine, because it can involve so many different patterns of symptoms, some of which may be mistaken for signs of infectious disease or stroke.[19]
The most common neuropsychiatric disorder people with SLE have is headache,[20] although the existence of a specific lupus headache and the optimal approach to headache in SLE cases remains controversial.[21] Other common neuropsychiatric manifestation of SLE include cognitive dysfunction, mood disorder, cerebrovascular disease,[20] seizures, polyneuropathy,[20] anxiety disorder, and psychosis. It can rarely present with intracranial hypertension syndrome, characterized by an elevated intracranial pressure, papilledema, and headache with occasional abducens nerve paresis, absence of a space-occupying lesion or ventricular enlargement, and normal cerebrospinal fluid chemical and hematological constituents.[22]
More rare manifestations are acute confusional state, Guillain-Barré syndrome, aseptic meningitis, autonomic disorder, demyelinating syndrome, mononeuropathy (which might manifest as mononeuritis multiplex), movement disorder (more specifically, chorea), myasthenia gravis, myelopathy, cranial neuropathy and plexopathy.
Neural symptoms contribute to a significant percentage of morbidity and mortality in patients with Lupus.[23] As a result, the neural side of Lupus is being studied in hopes of reducing morbidity and mortality rates[24]. The neural manifestation of lupus is known as Neuro Psychiatric Systematic Lupus Erythematosus (NPSLE). One aspect of this disease is severe damage to the epithelial cells of the blood-brain barrier.
Lupus has a wide range of symptoms which span out throughout the body. The neurological symptoms include headaches[20], depression, seizures, cognitive dysfunction, mood disorder, cerebrovascular disease[20], polyneuropathy[20], anxiety disorder, psychosis, and in some extreme cases, personality disorders.[25]
Fatigue in SLE is probably multifactorial and has been related to not only disease activity or complications such as anemia or hypothyroidism but also pain; depression; poor sleep quality; poor physical fitness and perceived lack of social support.[26][27]
There is no one specific cause of SLE. There are, however, a number of environmental triggers and a number of genetic susceptibilities.[28][29]
The first mechanism may arise genetically. Research indicates that SLE may have a genetic link. SLE does run in families, but no single, causal, gene has been identified. Instead, multiple genes appear to influence a person's chance of developing lupus when triggered by environmental factors. The most important genes are located in the HLA region on chromosome 6, where mutations may occur randomly (de novo) or may be inherited. HLA class I, class II, and class III are associated with SLE, but only class I and class II contribute independently to increased risk of SLE.[30] Other genes which contain risk variants for SLE are IRF5, PTPN22, STAT4[31], CDKN1A,[32] ITGAM, BLK[31], TNFSF4 and BANK1.[33] some of the susceptibility genes may be population specific.[31]
The second mechanism may be due to environmental factors. These factors may not only exacerbate existing SLE conditions but also trigger the initial onset. They include certain medications (such as some antidepressants and antibiotics), extreme stress, exposure to sunlight, hormones, and infections. UV radiation has been shown to trigger the photosensitive lupus rash and some evidence suggests that UV light might be capable of altering the structure of the DNA, leading to the creation of autoantibodies. Sex hormones such as estrogen play an important role in the occurrence of SLE and it is observed that during reproductive years, the frequency of SLE is 10 times greater in females than in males.
Researchers have sought to find a connection between certain infectious agents (viruses and bacteria), but no pathogen can be consistently linked to the disease. Some researchers have found that women with silicone gel-filled breast implants have produced antibodies to their own collagen, but it is not known how often these antibodies occur in the general population, and there is no data that show that these antibodies cause connective tissue diseases such as SLE. There is also a small but growing body of evidence linking SLE to lipstick usage,[34][35] although lipstick manufacturers do not appear to be concerned about it.[36]
Drug-induced lupus erythematosus is a (generally) reversible condition that usually occurs in people being treated for a long-term illness. Drug-induced lupus mimics SLE. However, symptoms of drug-induced lupus generally disappear once the medication that triggered the episode is stopped. There are about 400 medications that can cause this condition, the most common of which are procainamide, hydralazine, quinidine, and phenytoin.[3]
Discoid (cutaneous) lupus is limited to skin symptoms and is diagnosed by biopsy of rash on the face, neck, or scalp.
One manifestation of SLE is abnormalities in apoptosis, a type of programmed cell death in which aging or damaged cells are neatly disposed of as a part of normal growth or functioning.
In SLE, the body's immune system produces antibodies against itself, particularly against proteins in the cell nucleus. SLE is triggered by environmental factors that are unknown.
"All the key components of the immune system are involved in the underlying mechanisms [of SLE]" according to Rahman, and SLE is the prototypical autoimmune disease. The immune system must have a balance (homeostasis) between being sensitive enough to protect against infection, and being too sensitive and attacking the body's own proteins (autoimmunity). From an evolutionary perspective, according to Crow, the population must have enough genetic diversity to protect itself against a wide range of possible infection; some genetic combinations result in autoimmunity. The likely environmental triggers include ultraviolet light, drugs, and viruses. These stimuli cause the destruction of cells and expose their DNA, histones, and other proteins, particularly parts of the cell nucleus. Because of genetic variations in different components of the immune system, in some people the immune system attacks these nuclear-related proteins and produces antibodies against them. In the end, these antibody complexes damage blood vessels in critical areas of the body, such as the glomeruli of the kidney; these antibody attacks are the cause of SLE. Researchers are now identifying the individual genes, the proteins they produce, and their role in the immune system. Each protein is a link on the autoimmune chain, and researchers are trying to find drugs to break each of those links.[3][37][38]
SLE is a chronic inflammatory disease believed to be a type III hypersensitivity response with potential type II involvement.[39] Reticulate and stellate acral pigmentation should be considered a possible manifestation of SLE and high titers of anticardiolipin antibodies, or a consequence of therapy.[40]
Tingible body macrophages (TBMs) – large phagocytic cells in the germinal centers of secondary lymph nodes – express CD68 protein. These cells normally engulf B cells that have undergone apoptosis after somatic hypermutation. In some people with SLE, significantly fewer TBMs can be found, and these cells rarely contain material from apoptotic B cells. Also, uningested apoptotic nuclei can be found outside of TBMs. This material may present a threat to the tolerization of B cells and T cells. Dendritic cells in the germinal center may endocytose such antigenic material and present it to T cells, activating them. Also, apoptotic chromatin and nuclei may attach to the surfaces of follicular dendritic cells and make this material available for activating other B cells that may have randomly acquired self-specificity through somatic hypermutation.[41]
The exact mechanisms for the development of SLE are still unclear, since the pathogenesis is a multifactorial event. Beside discussed causations, impaired clearance of dying cells is a potential pathway for the development of this systemic autoimmune disease. This includes deficient phagocytic activity and scant serum components in addition to increased apoptosis.
Monocytes isolated from whole blood of SLE sufferers show reduced expression of CD44 surface molecules involved in the uptake of apoptotic cells. Most of the monocytes and tingible body macrophages (TBM), which are found in the germinal centres of lymph nodes, even show a definitely different morphology; they are smaller or scarce and die earlier. Serum components like complement factors, CRP, and some glycoproteins are, furthermore, decisively important for an efficiently operating phagocytosis. With SLE, these components are often missing, diminished, or inefficient.
The clearance of early apoptotic cells is an important function in multicellular organisms. It leads to a progression of the apoptosis process and finally to secondary necrosis of the cells if this ability is disturbed. Necrotic cells release nuclear fragments as potential autoantigens as well as internal danger signals, inducing maturation of dendritic cells (DC), since they have lost their membranes' integrity. Increased appearance of apoptotic cells also simulates inefficient clearance. That leads to maturation of DC and also to the presentation of intracellular antigens of late apoptotic or secondary necrotic cells, via MHC molecules. Autoimmunity possibly results by the extended exposure to nuclear and intracellular autoantigens derived from late apoptotic and secondary necrotic cells. B and T cell tolerance for apoptotic cells is abrogated, and the lymphocytes get activated by these autoantigens; inflammation and the production of autoantibodies by plasma cells is initiated. A clearance deficiency in the skin for apoptotic cells has also been observed in people with cutaneous lupus erythematosus (CLE).[42]
In healthy conditions, apoptotic lymphocytes are removed in germinal centres by specialized phagocytes, the tingible body macrophages (TBM), which is why no free apoptotic and potential autoantigenic material can be seen. In some people with SLE, accumulation of apoptotic debris can be observed in GC because of an ineffective clearance of apoptotic cells. In close proximity to TBM, follicular dendritic cells (FDC) are localised in GC, which attach antigen material to their surface and, in contrast to bone marrow-derived DC, neither take it up nor present it via MHC molecules.
Autoreactive B cells can accidentally emerge during somatic hypermutation and migrate into the GC light zone. Autoreactive B cells, maturated coincidentally, normally do not receive survival signals by antigen planted on follicular dendritic cells, and perish by apoptosis. In the case of clearance deficiency, apoptotic nuclear debris accumulates in the light zone of GC and gets attached to FDC. This serves as a germinal centre survival signal for autoreactive B-cells. After migration into the mantle zone, autoreactive B cells require further survival signals from autoreactive helper T cells, which promote the maturation of autoantibody-producing plasma cells and B memory cells. In the presence of autoreactive T cells, a chronic autoimmune disease may be the consequence.
Autoantibodies to nRNP A and nRNP C initially targeted restricted, proline-rich motifs. Antibody binding subsequently spread to other epitopes. The similarity and cross-reactivity between the initial targets of nRNP and Sm autoantibodies identifies a likely commonality in cause and a focal point for intermolecular epitope spreading.[43]
Elevated expression of HMGB1 was found in the sera of patients and mice with systemic lupus erythematosus, High Mobility Group Box 1 (HMGB1) is a nuclear protein participating in chromatin architecture and transcriptional regulation. Recently, there is increasing evidence that HMGB1 contributes to the pathogenesis of chronic inflammatory and autoimmune diseases due to its pro-inflammatory and immunostimulatory properties.[44]
Antinuclear antibody (ANA) testing and anti-extractable nuclear antigen (anti-ENA) form the mainstay of serologic testing for SLE. Several techniques are used to detect ANAs. Clinically the most widely used method is indirect immunofluorescence. The pattern of fluorescence suggests the type of antibody present in the patient's serum.
ANA screening yields positive results in many connective tissue disorders and other autoimmune diseases, and may occur in normal individuals. Subtypes of antinuclear antibodies include anti-Smith and anti-double stranded DNA (dsDNA) antibodies (which are linked to SLE) and anti-histone antibodies (which are linked to drug-induced lupus). Anti-dsDNA antibodies are highly specific for SLE; they are present in 70% of cases, whereas they appear in only 0.5% of people without SLE.[3] The anti-dsDNA antibody titers also tend to reflect disease activity, although not in all cases.[3] Other ANA that may occur in SLE sufferers are anti-U1 RNP (which also appears in systemic sclerosis), SS-A (or anti-Ro) and SS-B (or anti-La; both of which are more common in Sjögren's syndrome). SS-A and SS-B confer a specific risk for heart conduction block in neonatal lupus.[45]
Other tests routinely performed in suspected SLE are complement system levels (low levels suggest consumption by the immune system), electrolytes and renal function (disturbed if the kidney is involved), liver enzymes, and complete blood count.
Previously, the lupus erythematosus (LE) cell test was not commonly used for diagnosis because those LE cells are only found in 50–75% of SLE cases, and are also found in some people with rheumatoid arthritis, scleroderma, and drug sensitivities. Because of this, the LE cell test is now performed only rarely and is mostly of historical significance.[46]
Some physicians make a diagnosis on the basis of the American College of Rheumatology (ACR) classification criteria. The criteria, however, were established mainly for use in scientific research including use in randomized controlled trials which require higher confidence levels, so some people with SLE may not pass the full criteria.
The American College of Rheumatology established eleven criteria in 1982,[47] which were revised in 1997[48] as a classificatory instrument to operationalise the definition of SLE in clinical trials. They were not intended to be used to diagnose individuals and do not do well in that capacity. For the purpose of identifying patients for clinical studies, a person has SLE if any 4 out of 11 symptoms are present simultaneously or serially on two separate occasions.
The mnemonic to remember the 11 symptoms is 'SOAP BRAIN MD'.[51]
Some people, especially those with antiphospholipid syndrome, may have SLE without four of the above criteria, and also SLE may present with features other than those listed in the criteria.[52][53][54]
Recursive partitioning has been used to identify more parsimonious criteria.[49] This analysis presented two diagnostic classification trees:
Other alternative criteria have been suggested, eg. the St. Thomas' Hospital "alternative" criteria in 1998.[55]
SLE is not understood well enough to be prevented, but, when the disease develops, quality of life can be improved through flare prevention. The warning signs of an impending flare include increased fatigue, pain, rash, fever, abdominal discomfort, headache, and dizziness. Early recognition of warning signs and good communication with a doctor can help individuals remain active, experience less pain, and reduce medical visits.[56]
As longevity of people with SLE increases, the likelihood of complications also increases in four areas: cardiovascular disease, infections, osteoporosis, and cancer. Standard preventive measures, screening for related diseases may be necessary to deal with the increased risks due to the side effects of medications. Extra vigilance is considered warranted in particular for cancers affecting the immune system.[57]
While most infants born to mothers who have SLE are healthy, pregnant mothers with SLE should remain under medical care until delivery. Neonatal lupus is rare, but identification of mothers at highest risk for complications allows for prompt treatment before or after birth. In addition, SLE can flare up during pregnancy, and proper treatment can maintain the health of the mother longer. Women pregnant and known to have the antibodies for anti-Ro (SSA) or anti-La (SSB) often have echocardiograms during the 16th and 30th weeks of pregnancy to monitor the health of the heart and surrounding vasculature.[56]
Contraception and other reliable forms of pregnancy prevention is routinely advised for women with SLE, since getting pregnant during active disease was found to be harmful. Lupus nephritis was the most common manifestation. Overall live-birth was 72.7%; the most common causes of pregnancy loss were spontaneous abortion (miscarriage) and fetal death in utero. Pregnancy outcome was worse in SLE patients whose disease flared up during pregnancy.[58]
The treatment of SLE involves preventing flares and reducing their severity and duration when they occur.
Treatment can include corticosteroids and anti-malarial drugs. Certain types of lupus nephritis such as diffuse proliferative glomerulonephritis require bouts of cytotoxic drugs. These drugs include cyclophosphamide and mycophenolate.
Hydroxychloroquine (HCQ) was the last medication approved by the FDA for lupus in 1955.[59] Some drugs approved for other diseases are used for SLE 'off-label'.
Due to the variety of symptoms and organ system involvement with SLE, its severity in an individual must be assessed in order to successfully treat SLE. Mild or remittant disease can sometimes be safely left untreated. If required, nonsteroidal anti-inflammatory drugs and antimalarials may be used. A number of potential treatments are in clinical trials.[60]
Disease-modifying antirheumatic drugs (DMARDs) are used preventively to reduce the incidence of flares, the process of the disease, and lower the need for steroid use; when flares occur, they are treated with corticosteroids. DMARDs commonly in use are antimalarials such as plaquenil and immunosuppressants (e.g. methotrexate and azathioprine). Hydroxychloroquine is an FDA-approved antimalarial used for constitutional, cutaneous, and articular manifestations. Hydroxychloroquine has relatively few side effects, and there is evidence that it improves survival among people who have SLE.[59] Cyclophosphamide is used for severe glomerulonephritis or other organ-damaging complications. Mycophenolic acid is also used for treatment of lupus nephritis, but it is not FDA-approved for this indication, and FDA is investigating reports that it may be associated with birth defects when used by pregnant women.[61]
In more severe cases, medications that modulate the immune system (primarily corticosteroids and immunosuppressants) are used to control the disease and prevent recurrence of symptoms (known as flares). Depending on the dosage, people who require steroids may develop Cushing's syndrome, side-effects of which may include obesity, puffy round face, diabetes mellitus, large appetite, difficulty sleeping and osteoporosis. Those side-effects can subside if and when the large initial dosage is reduced, but long-term use of even low doses can cause elevated blood pressure and cataracts.
Numerous new immunosuppressive drugs are being actively tested for SLE. Rather than suppressing the immune system nonspecifically, as corticosteroids do, they target the responses of individual [types of] immune cells. Some of these drugs are already FDA-approved for treatment of rheumatoid arthritis.[59] See also Belimumab and Atacicept. Lupuzor has given encouraging results in a phase IIb trial[62]
Since a large percentage of people with SLE suffer from varying amounts of chronic pain, stronger prescription analgesics (pain killers) may be used if over-the-counter drugs (mainly nonsteroidal anti-inflammatory drugs) do not provide effective relief. Potent NSAIDs such as indomethacin and diclofenac are relatively contraindicated for patients with SLE because they increase the risk of kidney failure and heart failure.[59]
Moderate pain is typically treated with mild prescription opiates such as dextropropoxyphene and co-codamol. Moderate to severe chronic pain is treated with stronger opioids, such as hydrocodone or longer-acting continuous-release opioids, such as oxycodone, MS Contin, or Methadone. The Fentanyl duragesic transdermal patch is also a widely-used treatment option for the chronic pain caused by complications because of its long-acting timed release and ease of use. When opioids are used for prolonged periods, drug tolerance, chemical dependency, and addiction may occur. Opiate addiction is not typically a concern, since the condition is not likely to ever completely disappear. Thus, lifelong treatment with opioids is fairly common for chronic pain symptoms, accompanied by periodic titration that is typical of any long-term opioid regimen.
Avoiding sunlight is the primary change to the lifestyle of SLE sufferers, as sunlight is known to exacerbate the disease. Drugs unrelated to SLE should be prescribed only when known not to exacerbate the disease. Occupational exposure to silica, pesticides and mercury can also make the disease worsen.[28]
Renal transplants are the treatment of choice for end-stage renal disease, which is one of the complications of lupus nephritis, but the recurrence of the full disease is common in up to 30% of patients.[63]
Hughes syndrome, also known as the antiphospholipid syndrome or sticky blood syndrome, is also related to the onset of neural lupus symptoms in the brain. In this form of the disease the cause is very different from Lupus: blood clots or 'sticky blood' form - refers to the formation of thromboses (blood clots) in blood vessels, which prove to be fatal if they move within the blood stream[64]. If the thromboses migrate to the brain, they can potentially cause a stroke by blocking the blood supply to the brain! If this disorder is suspected in patients, brain scans are usually required for early detection. These scans can show localized areas of the brain where blood supply has not been adequate. The treatment plan for these patients requires thinning of the blood, either with aspirin or, in more severe cases, with anticoagulants such as warfarin and/or leeches[65].
SLE is considered incurable, but highly treatable.
In the 1950s, most people diagnosed with SLE lived fewer than five years. Advances in diagnosis and treatment have improved survival to the point where over 90% now survive for more than ten years, and many can live relatively asymptomatically. Prognosis is normally worse for men and children than for women; however, if symptoms are present after age 60, the disease tends to run a more benign course. Early mortality, within 5 years, is due to organ failure or overwhelming infections, both of which can be modified by early diagnosis and treatment. The mortality risk is fivefold when compared to the normal population in the late stages, which can be attributed to cardiovascular diseases acquired from corticosteroid therapy, the leading cause of death for people with SLE.[59]
To reduce potential for cardiovascular issues, high blood pressure and high cholesterol should be prevented or treated aggressively. Steroids should be used at the lowest dose for the shortest possible period, and other drugs that can reduce symptoms should be used whenever possible.[59] High serum creatinine, hypertension, nephrotic syndrome, anemia and hypoalbuminemia are poor prognostic factors.[66]
The ANA is the most sensitive screening test for evaluation, whereas anti-Sm (anti-Smith) is the most specific. The dsDNA (double-stranded DNA) antibody is also fairly specific and often fluctuates with disease activity; as such, the dsDNA titer is sometimes useful to monitor disease flares or response to treatment.[67]
The rate of SLE varies considerable between countries, ethnicity, by gender, and has changed over time.[68] In the United States the prevalence of SLE is estimated to be about 53 per 100,000, translating to about 159,000 out of 300 million people in the US being affected.[68][69] In Northern Europe the rate is about 40 per 100,000 people.[70] SLE occurs more frequently and with greater severity among those of non-European descent.[69] That rate has been found to be as high as 159 per 100,000 among those of Afro-Caribbean descent.[68]
SLE, like many autoimmune diseases, affects females more frequently than males, at a rate of almost 9 to 1.[68]
The incidence of SLE in the United States increased from 1.0 in 1955 to 7.6 in 1974. Whether the increase is due to better diagnosis or to increasing frequency of the disease is unknown.[68]
There are several explanations ventured for the term lupus erythematosus. Lupus is Latin for wolf [71], and "erythro" is derived from ερυθρός, Greek for "red." All explanations originate with the reddish, butterfly-shaped malar rash that the disease classically exhibits across the nose and cheeks.
The history of SLE can be divided into three periods: classical, neoclassical, and modern. The classical period began when the disease was first recognized in the Middle Ages and saw the description of the dermatological manifestation of the disorder. The term lupus is attributed to 12th-century physician Rogerius, who used it to describe the classic malar rash. The neoclassical period was heralded by Móric Kaposi's recognition in 1872 of the systemic manifestations of the disease. The modern period began in 1948 with the discovery of the LE cell (the lupus erythematosus cell—a misnomer, as it occurs with other diseases as well) and is characterised by advances in our knowledge of the pathophysiology and clinical-laboratory features of the disease, as well as advances in treatment.[72]
Medical historians have theorized that people with porphyria (a disease that shares many symptoms with SLE) generated folklore stories of vampires and werewolves, due to the photosensitivity, scarring, hair growth, and porphyrin brownish-red stained teeth in severe recessive forms of porphyria (or combinations of the disorder, known as dual, homozygous, or compound heterozygous porphyrias).[72]
Useful medication for the disease was first found in 1894, when quinine was first reported as an effective therapy. Four years later, the use of salicylates in conjunction with quinine was noted to be of still greater benefit. This was the best available treatment until the middle of the twentieth century, when Hench discovered the efficacy of corticosteroids in the treatment of SLE.[72]
Since Lupus is considered to be currently untreatable, current research is being geared towards finding a possible cause, cure and more effective treatment plans to increase the quality and longevity of life for lupus patients.
Several papers discuss the importance of the presence of antibodies in the brain that are only produced in patients with Lupus. One such paper, highlights the inhibition of astrocyte proliferation in brain tissue from Lupus patient serum[93]. Astrocytes are glial cells in the brain that participate in the support of cells that form the blood brain barrier. They are extremely useful in that they provide a nutritional balance between ions in the brain, keeping it at a normal level[94]. Therefore studying the effect Lupus has on astrocytes is extremely important. For this study, the researchers used immunofluorescence to track the antibodies near the corpus callosum to see if anticardiolipin antibodies have an inhibitory effect on brain cells; and if they elicit thrombus formation in brain vessels, which does play a part in neuropsychiatric lupus.
However a majority of the recent papers focus on the blood brain barrier and its effect on lupus. It was found that 20–70% of lupus patients with neurological symptoms have some form of a central nervous system involvement[95]. This can be determined using various imaging methods as well as using a cerebral spinal fluid tap. However the focus of most of the studies on neurological symptoms in lupus patients focuses more on blood brain barrier damage. This ties along with the astrocyte study however the focus is not antibodies but rather the impact the damage of the blood brain barrier has on the onset of lupus. In a study conducted in London, the researchers measured the albumin content in the brain using imaging and spinal fluid. The images were used to illustrate blood brain barrier damage while the spinal tap was used to measure the protein content in the brain. Albumin is a protein that can be carried into the brain through the blood brain barrier by other transport proteins. If the ratio of albumin outside the barrier to inside the barrier is high, this means that either the barrier is damaged, or the transport proteins are not functioning well. This blood brain barrier damage can impact Lupus patients by increasing their discomfort and increasing the intensity of the disease[96].
In terms of new drugs/medication that are being researched, a new drug was just used in a study, claimed it could treat systemic lupus! This study was called BLISS- 76 which tested the drug, Belimumab (HGS1006, LymphoStat-B™ ), a Fully Human Monoclonal Anti-BLyS Antibody. This drug stimulates B lymphocytes extending the life of B Cells, which produce antibodies against foreign and self cells - which is what an autoimmune disease essentially does. Research is still being conducted for this drug and is not yet ready to be released into the market[97]
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