Autoantibody

Last updated

An autoantibody is an antibody (a type of protein) produced by the immune system that is directed against one or more of the individual's own proteins. Many autoimmune diseases (notably lupus erythematosus) are associated with such antibodies.

Contents

Production

Antibodies are produced by B cells in two ways: (i) randomly, and (ii) in response to a foreign protein or substance within the body. Initially, one B cell produces one specific kind of antibody. In either case, the B cell is allowed to proliferate or is killed off through a process called clonal deletion. Normally, the immune system is able to recognize and ignore the body's own healthy proteins, cells, and tissues, and to not overreact to non-threatening substances in the environment, such as foods. Sometimes, the immune system ceases to recognize one or more of the body's normal constituents as "self", leading to production of pathological autoantibodies. Autoantibodies may also play a nonpathological role; for instance they may help the body to destroy cancers and to eliminate waste products. The role of autoantibodies in normal immune function is also a subject of scientific research.

Cause

The causes of autoantibody production are varied and not well understood. It is thought that some autoantibody production is due to a genetic predisposition combined with an environmental trigger, such as a viral illness or a prolonged exposure to certain toxic chemicals. There is generally not a direct genetic link however. While families may be susceptible to autoimmune conditions, individual family members may have different autoimmune disorders, or may never develop an autoimmune condition. Researchers believe that there may also be a hormonal component as many of the autoimmune conditions are much more prevalent in women of childbearing age. While the initial event that leads to the production of autoantibodies is still unknown, there is a body of evidence that autoantibodies may have the capacity to maintain their production. [1] [2]

Diseases

The type of autoimmune disorder or disease that occurs and the amount of destruction done to the body depends on which systems or organs are targeted by the autoantibodies, and how strongly. Disorders caused by organ specific autoantibodies, those that primarily target a single organ, (such as the thyroid in Graves' disease and Hashimoto's thyroiditis), are often the easiest to diagnose as they frequently present with organ related symptoms. Disorders due to systemic autoantibodies can be much more elusive. Although the associated autoimmune disorders are rare, the signs and symptoms they cause are relatively common. Symptoms may include: arthritis-type joint pain, fatigue, fever, rashes, cold or allergy-type symptoms, weight loss, and muscular weakness. Associated conditions include vasculitis which are inflammation of blood vessels and anemia. Even if they are due to a particular systemic autoimmune condition, the symptoms will vary from person to person, vary over time, vary with organ involvement, and they may taper off or flare unexpectedly. Add to this the fact that a person may have more than one autoantibody, and thus have more than one autoimmune disorder, and/or have an autoimmune disorder without a detectable level of an autoantibody, complicating making a diagnosis.

The diagnosis of disorders associated with systemic autoantibodies starts with a complete medical history and a thorough physical exam. Based on the patient's signs and symptoms, the doctor may request one or more diagnostic studies that will help to identify a specific disease. As a rule, information is required from multiple sources, rather than a single laboratory test to accurately diagnose disorders associated with systemic autoantibodies. Tests may include:

Indications for autoantibody tests

Autoantibody tests may be ordered as part of an investigation of chronic progressive arthritis type symptoms and/or unexplained fevers, fatigue, muscle weakness and rashes. The antinuclear antibody (ANA) test is often ordered first. ANA is a marker of the autoimmune process – it is positive with a variety of different autoimmune diseases but not specific. Consequently, if an ANA test is positive, it is often followed up with other tests associated with arthritis and inflammation, such as a rheumatoid factor (RF), an erythrocyte sedimentation rate (ESR), a c-reactive protein (CRP), and/or complement protein|complement levels.

A single autoantibody test is not diagnostic, but may give clues as to whether a particular disorder is likely or unlikely to be present. Each autoantibody result should be considered individually and as part of the group. Some disorders, such as systemic lupus erythematosus (SLE) may be more likely if several autoantibodies are present, while others, such as mixed connective tissue disease (MCTD) may be more likely if a single autoantibody, ribonucleic protein (RNP), is the only one present. Those who have more than one autoimmune disorder may have several detectable autoantibodies.

Whether a particular autoantibody will be present is both very individual and a matter of statistics. Each will be present in a certain percentage of people who have a particular autoimmune disorder. For instance, up to 80% of those with SLE will have a positive double strand anti-double stranded DNA (anti-dsDNA) autoantibody test, but only about 25–30% will have a positive RNP. Some individuals who do have an autoimmune disorder will have negative autoantibody test results, but at a later date – as the disorder progresses - the autoantibodies may develop.

Systemic autoantibody tests are used to:

Antibody profiling

Antibody profiling is used for identifying persons from forensic samples. The technology can uniquely identify a person by analyzing the antibodies in body fluids. A unique, individual set of antibodies, called individual specific autoantibodies (ISA), is found in blood, serum, saliva, urine, semen, perspiration, tears, and body tissues, and the antibodies are not affected by illness, medication, or food/drug intake. An unskilled technician using inexpensive equipment can complete a test in a couple of hours. [3]

List of some autoantibodies and commonly associated diseases

Note: the sensitivity and specificity of various autoantibodies for a particular disease is different for different diseases.

AutoantibodyAntibody targetCondition
Antinuclear antibodies Anti-SSA/Ro autoantibodies ribonucleoproteins systemic lupus erythematosus, neonatal heart block, primary Sjögren syndrome
Anti-La/SS-B autoantibodiesPrimary Sjögren syndrome
Anti-centromere antibodies centromere CREST syndrome
Anti-dsDNA double-stranded DNA SLE
Anti-Jo1 histidine-tRNA ligase inflammatory myopathy
Anti-RNP Ribonucleoprotein Mixed connective tissue disease
Anti-Smith snRNP core proteins SLE
Anti-topoisomerase antibodies Type I topoisomerase systemic sclerosis (anti-Scl-70 antibodies)
Anti-histone antibodies histones SLE and drug-induced LE [4]
Anti-p62 antibodies [5] nucleoporin 62 primary biliary cirrhosis [5] [6] [7]
Anti-sp100 antibodies [6] Sp100 nuclear antigen
Anti-glycoprotein-210 antibodies [7] nucleoporin 210kDa
Anti-transglutaminase antibodies Anti-tTG celiac disease
Anti-eTG dermatitis herpetiformis
Anti-ganglioside antibodies ganglioside GQ1B Miller Fisher syndrome
ganglioside GD3 acute motor axonal neuropathy (AMAN)
ganglioside GM1multifocal motor neuropathy with conduction block (MMN)
Anti-actin antibodies actin Coeliac disease (antibody levels correlate with the level of intestinal damage [8] [9] ), autoimmune hepatitis, gastric cancer
anti-CCP cyclic citrullinated peptide rheumatoid arthritis
Liver kidney microsomal type 1 antibody autoimmune hepatitis [10]
Lupus anticoagulant Anti-thrombin antibodies thrombin systemic lupus erythematosus
Antiphospholipid antibodies phospholipid antiphospholipid syndrome
Anti-neutrophil cytoplasmic antibody c-ANCA proteins in neutrophil cytoplasm granulomatosis with polyangiitis
p-ANCA neutrophil perinuclear microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis, systemic vasculitides (non-specific)
Rheumatoid factor IgG rheumatoid arthritis
Anti-smooth muscle antibody smooth muscle chronic autoimmune hepatitis
Anti-mitochondrial antibody mitochondria primary biliary cirrhosis [11]
Anti-SRP signal recognition particle dermatomyositis [12]
exosome complex scleromyositis
Anti-AChR nicotinic acetylcholine receptor myasthenia gravis
Anti-MUSK Muscle-specific kinase (MUSK) myasthenia gravis
Anti-VGCC voltage-gated calcium channel (P/Q-type) Lambert–Eaton myasthenic syndrome
Anti-Vinculin vinculin small intestinal bacterial overgrowth
Anti-thyroid autoantibodies Anti-TPO antibodies Thyroid peroxidase (microsomal) Hashimoto's thyroiditis, Graves' disease
Anti-thyroglobulin antibodies (TgAbs) Thyroglobulin Hashimoto's thyroiditis
Anti-thyrotropin receptor antibodies (TRAbs) TSH receptor Graves' disease
Anti-Hu (ANNA-1)Neuronal nuclear proteins paraneoplastic cerebellar degeneration, limbic encephalitis, encephalomyelitis, subacute sensory neuronopathy, choreathetosis [13]
Anti-YoCerebellar Purkinje cells paraneoplastic cerebellar degeneration
Anti-Ma encephalomyelitis, limbic encephalitis
Anti-Ri (ANNA-2)Neuronal nuclear proteins opsoclonus myoclonus syndrome
Anti-Tr glutamate receptor paraneoplastic cerebellar syndrome
Anti-amphiphysin amphiphysin stiff person syndrome, paraneoplastic cerebellar degeneration
Anti-GAD Glutamate decarboxylase stiff person syndrome, diabetes mellitus type 1
Anti-VGKC voltage-gated potassium channel (VGKC) limbic encephalitis, Isaac's Syndrome (autoimmune neuromyotonia)
Anti-CRMP-5 Collapsin response mediator protein 5 optic neuropathy, chorea
basal ganglia neurons Sydenham's chorea, paediatric autoimmune neuropsychiatric disease associated with Streptococcus (PANDAS)
Anti-NMDAr N-methyl-D-aspartate receptor (NMDA) anti-NMDA receptor encephalitis
NMO antibody aquaporin-4 neuromyelitis optica (Devic's syndrome)
Anti-desmoglein (anti-desmosome) Dsg3 (Desmoglein 3) and sometimes Dsg1 Pemphigus vulgaris
Anti-hemidesmosomehemidesmosomes Bullous pemphigoid
Anti-glomerular basement membranebasement membrane in lungs and kidneys Goodpasture syndrome
Anti-parietal cellgastric parietal cells Pernicious anemia
Anti-intrinsic factorintrinsic factor Pernicious anemia
Anti-phospholipase A2 receptorphospholipase A2 receptor Membranous nephropathy

See also

Related Research Articles

<span class="mw-page-title-main">Sjögren syndrome</span> Autoimmune disease affecting the bodys moisture-producing glands

Sjögren syndrome or Sjögren's syndrome is a long-term autoimmune disease that affects the body's moisture-producing glands, and often seriously affects other organ systems, such as the lungs, kidneys, and nervous system.

<span class="mw-page-title-main">Autoimmunity</span> Immune response against an organisms own healthy cells

In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". Prominent examples include celiac disease, diabetes mellitus type 1, Henoch–Schönlein purpura (HSP), systemic lupus erythematosus (SLE), Sjögren syndrome, eosinophilic granulomatosis with polyangiitis, Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, Addison's disease, rheumatoid arthritis (RA), ankylosing spondylitis, polymyositis (PM), dermatomyositis (DM), and multiple sclerosis (MS). Autoimmune diseases are very often treated with steroids.

<span class="mw-page-title-main">Antinuclear antibody</span> Autoantibody that binds to contents of the cell nucleus

Antinuclear antibodies are autoantibodies that bind to contents of the cell nucleus. In normal individuals, the immune system produces antibodies to foreign proteins (antigens) but not to human proteins (autoantigens). In some cases, antibodies to human antigens are produced.

<span class="mw-page-title-main">Autoimmune hepatitis</span> Chronic, autoimmune disease of the liver

Autoimmune hepatitis, formerly known as lupoid hepatitis, plasma cell hepatitis, or autoimmune chronic active hepatitis, is a chronic, autoimmune disease of the liver that occurs when the body's immune system attacks liver cells, causing the liver to be inflamed. Common initial symptoms may include fatigue, nausea, muscle aches, or weight loss or signs of acute liver inflammation including fever, jaundice, and right upper quadrant abdominal pain. Individuals with autoimmune hepatitis often have no initial symptoms and the disease may be detected by abnormal liver function tests and increased protein levels during routine bloodwork or the observation of an abnormal-looking liver during abdominal surgery.

<span class="mw-page-title-main">Primary biliary cholangitis</span> Autoimmune disease of the liver

Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis, is an autoimmune disease of the liver. It results from a slow, progressive destruction of the small bile ducts of the liver, causing bile and other toxins to build up in the liver, a condition called cholestasis. Further slow damage to the liver tissue can lead to scarring, fibrosis, and eventually cirrhosis.

Rheumatoid factor (RF) is the autoantibody that was first found in rheumatoid arthritis. It is defined as an antibody against the Fc portion of IgG and different RFs can recognize different parts of the IgG-Fc. RF and IgG join to form immune complexes that contribute to the disease process such as chronic inflammation and joint destruction at the synovium and cartilage.

A connective tissue disease is a disease which involves damage to, or destruction of, any type of connective tissue in the body. Depending on the specific disease, the affected tissue(s) may be a single specific type, a group of several related tissues, or a wide variety of unrelated types of connective tissue. Some of the most common connective tissue diseases involve injury to collagen and elastin as a result of inflammation. Many connective tissue diseases are strongly connected to autoimmune disease processes.

<span class="mw-page-title-main">Myositis</span> Medical condition

Myositis is a rarely-encountered medical condition characterized by inflammation affecting the muscles. The manifestations of this condition may include skin issues, muscle weakness, and the potential involvement of other organs. Additionally, systemic symptoms like weight loss, fatigue, and low-grade fever can manifest in individuals with myositis.

<span class="mw-page-title-main">Anti-mitochondrial antibody</span> Autoantibodies against liver mitochondria, indicating primary biliary cholangitis

Anti-mitochondrial antibodies (AMA) are autoantibodies, consisting of immunoglobulins formed against mitochondria, primarily the mitochondria in cells of the liver.

Extractable nuclear antigens (ENAs) are over 100 different soluble cytoplasmic and nuclear antigens. They are known as "extractable" because they can be removed from cell nuclei using saline and represent six main proteins: Ro, La, Sm, RNP, Scl-70, Jo1. Most ENAs are part of spliceosomes or nucleosomes complexes and are a type of small nuclear ribonucleoprotein (snRNPS). The location in the nucleus and association with spliceosomes or nucleosomes results in these ENAs being associated with additional RNA and proteins such as polymerases. This quality of ENAs often makes it difficult to purify and quantify their presence for clinical use.

Mixed connective tissue disease, commonly abbreviated as MCTD, is an autoimmune disease characterized by the presence of elevated blood levels of a specific autoantibody, now called anti-U1 ribonucleoprotein (RNP) together with a mix of symptoms of systemic lupus erythematosus (SLE), scleroderma, and polymyositis. The idea behind the "mixed" disease is that this specific autoantibody is also present in other autoimmune diseases such as systemic lupus erythematosus, polymyositis, scleroderma, etc. MCTD was characterized as an individual disease in 1972 by Sharp et al., and the term was introduced by Leroy in 1980.

Scleromyositis, is an autoimmune disease. People with scleromyositis have symptoms of both systemic scleroderma and either polymyositis or dermatomyositis, and is therefore considered an overlap syndrome. Although it is a rare disease, it is one of the more common overlap syndromes seen in scleroderma patients, together with MCTD and Antisynthetase syndrome. Autoantibodies often found in these patients are the anti-PM/Scl (anti-exosome) antibodies.

<span class="mw-page-title-main">Autoimmune disease</span> Disorders of adaptive immune system

An autoimmune disease is a condition that results from an anomalous response of the adaptive immune system, wherein it mistakenly targets and attacks healthy, functioning parts of the body as if they were foreign organisms. It is estimated that there are more than 80 recognized autoimmune diseases, with recent scientific evidence suggesting the existence of potentially more than 100 distinct conditions. Nearly any body part can be involved.

<span class="mw-page-title-main">Anti-dsDNA antibodies</span> Group of anti-nuclear antibodies

Anti-double stranded DNA (Anti-dsDNA) antibodies are a group of anti-nuclear antibodies (ANA) the target antigen of which is double stranded DNA. Blood tests such as enzyme-linked immunosorbent assay (ELISA) and immunofluorescence are routinely performed to detect anti-dsDNA antibodies in diagnostic laboratories. They are highly diagnostic of systemic lupus erythematosus (SLE) and are implicated in the pathogenesis of lupus nephritis.

<span class="mw-page-title-main">Lupus</span> Human autoimmune disease

Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Common symptoms include painful and swollen joints, fever, chest pain, hair loss, mouth ulcers, swollen lymph nodes, feeling tired, and a red rash which is most commonly on the face. Often there are periods of illness, called flares, and periods of remission during which there are few symptoms.

Detection of autoantibodies against mutated citrullinated vimentin is part of rheumatoid arthritis (RA) diagnostics, especially in sera negative for rheumatoid factor. Anti-MCV antibodies are a member of the ACPA family, a group of the so-called antibodies to citrullinated protein/peptide antigens.

Undifferentiated connective tissue disease (UCTD) is a disease in which the connective tissues are targeted by the immune system. It is a serological and clinical manifestation of an autoimmune disease. When there is proof of an autoimmune disease, it will be diagnosed as UCTD if the disease doesn't answer to any criterion of specific autoimmune disease. This is also the case of major rheumatic diseases whose early phase was defined by LeRoy et al. in 1980 as undifferentiated connective tissue disease. The latent Lupus and the incomplete lupus are alternative terms used to describe this condition.

Anti-histone antibodies are autoantibodies that are a subset of the anti-nuclear antibody family, which specifically target histone protein subunits or histone complexes. They were first reported by Henry Kunkel, H.R. Holman, and H.R.G. Dreicher in their studies of cellular causes of lupus erythematosus in 1959–60. Today, anti-histone antibodies are still used as a marker for systemic lupus erythematosus, but are also implicated in other autoimmune diseases like Sjögren syndrome, dermatomyositis, or rheumatoid arthritis. Anti-histone antibodies can be used as a marker for drug-induced lupus.

<span class="mw-page-title-main">Anti-SSA/Ro autoantibodies</span> Type of anti-nuclear autoantibodies

Anti-SSA autoantibodies are a type of anti-nuclear autoantibodies that are associated with many autoimmune diseases, such as systemic lupus erythematosus (SLE), SS/SLE overlap syndrome, subacute cutaneous lupus erythematosus (SCLE), neonatal lupus and primary biliary cirrhosis. They are often present in Sjögren's syndrome (SS). Additionally, Anti-Ro/SSA can be found in other autoimmune diseases such as systemic sclerosis (SSc), polymyositis/dermatomyositis (PM/DM), rheumatoid arthritis (RA), and mixed connective tissue disease (MCTD), and are also associated with heart arrhythmia.

Autoimmunity refers to a pathological immune response of the body's immune system against itself. Autoimmune disease is widely recognized to be significantly more common in women than in men, and often presents differently between the sexes. The reasons for these disparities are still under investigation, but may in part involve the presence of an additional X chromosome in women, as well as the higher presence of female sex hormones such as estrogen. The risk, incidence, and character of autoimmune disease in women may also be associated with female-specific physiological changes, such as hormonal shifts during menses, pregnancy, and menopause.

References

  1. ↑ Böhm I. Apoptosis: the link between autoantibodies and leuko-/lymphocytopenia in patients. Scand J Rheumatol 2004;33: 409 - 416
  2. ↑ Böhm I. Disruption of the cytoskeleton after apoptosis induction by autoantibodies. Autoimmunity 2003;36: 183 - 189
  3. ↑ https://inlportal.inl.gov/portal/server.pt/community/idaho_national_laboratory_biological_systems/352/molecular_forensics/2691 Antibody Sensors
  4. ↑ Table 5-9 in: Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson (2007). Robbins Basic Pathology. Philadelphia: Saunders. ISBN   978-1-4160-2973-1. 8th edition.
  5. 1 2 Wesierska-Gadek J, Hohenuer H, Hitchman E, Penner E (1996). "Autoantibodies against nucleoporin p62 constitute a novel marker of primary biliary cirrhosis". Gastroenterology. 110 (3): 840–7. doi: 10.1053/gast.1996.v110.pm8608894 . PMID   8608894.
  6. 1 2 Szostecki C, Guldner HH, Netter HJ, Will H (1990). "Isolation and characterization of cDNA encoding a human nuclear antigen predominantly recognized by autoantibodies from patients with primary biliary cirrhosis". J. Immunol. 145 (12): 4338–47. doi: 10.4049/jimmunol.145.12.4338 . PMID   2258622. S2CID   43572051.
  7. 1 2 Itoh S, Ichida T, Yoshida T, et al. (1998). "Autoantibodies against a 210 kDa glycoprotein of the nuclear pore complex as a prognostic marker in patients with primary biliary cirrhosis". J. Gastroenterol. Hepatol. 13 (3): 257–65. doi:10.1111/j.1440-1746.1998.01553.x. PMID   9570238. S2CID   73008610.
  8. ↑ Pedreira S, Sugai E, Moreno ML, et al. (2005). "Significance of smooth muscle/anti-actin autoantibodies in celiac disease". Acta Gastroenterol. Latinoam. 35 (2): 83–93. PMID   16127984.
  9. ↑ Carroccio A, Brusca I, Iacono G, et al. (2007). "IgA anti-actin antibodies ELISA in coeliac disease: A multicentre study". Digestive and Liver Disease. 39 (9): 818–23. doi:10.1016/j.dld.2007.06.004. hdl: 10447/34417 . PMID   17652043.
  10. ↑ Kerkar N, Ma Y, Davies ET, Cheeseman P, Mieli-Vergani G, Vergani D (December 2002). "Detection of liver kidney microsomal type 1 antibody using molecularly based immunoassays". J. Clin. Pathol. 55 (12): 906–9. doi:10.1136/jcp.55.12.906. PMC   1769836 . PMID   12461054.
  11. ↑ Oertelt S, Rieger R, Selmi C, Invernizzi P, Ansari A, Coppel R, Podda M, Leung P, Gershwin M (2007). "A sensitive bead assay for antimitochondrial antibodies: Chipping away at AMA-negative primary biliary cirrhosis". Hepatology. 45 (3): 659–65. doi: 10.1002/hep.21583 . PMID   17326160. S2CID   19227989.
  12. ↑ Kao, A. H.; Lacomis, D.; Lucas, M.; Fertig, N.; Oddis, C. V. (2004). "Anti-signal recognition particle autoantibody in patients with and patients without idiopathic inflammatory myopathy". Arthritis & Rheumatism. 50 (1): 209–215. doi:10.1002/art.11484. PMID   14730618.
  13. ↑ Ropper, Allan H.; Samuels, Martin A. (2009). Adams and Victor's Principles of Neurology (9th ed.). McGraw Hill. p. 656. ISBN   978-0-07-149992-7.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.