An autoantibody is an antibody protein produced by the immune system that is directed against one or more of the individual’s own proteins. 

Many autoimmune diseases are associated with such antibodies.

Auto antibodies are produced by B cells and plasma cells, that target the bodies own cells, tissues, and proteins. 

The presence of autoantibodies can suggest an underlying pathophysiological process. 

Autoantibodies may be produced years before clinical symptoms of disease become apparent, and sometimes they are present in healthy individuals.

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, 

Each B cell produces one specific kind of antibody. 

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.

This also prevents overreaction to non-threatening substances in the environment, such as foods. 

When the immune system ceases to recognize one or more of the body’s normal constituents as its self, it leads to production of pathological autoantibodies. 

Autoantibodies play a nonpathological role to help the body to destroy cancers and to eliminate waste products.

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. 

Autoantibody production is generally not due to a direct genetic link.

 Families may be susceptible to autoimmune conditions, individual family members may have different autoimmune disorders, or may never develop an autoimmune condition. 

There may also be a hormonal component to autoantibody formation as many autoimmune conditions are much more prevalent in women of childbearing age. 

There evidence that autoantibodies may have the capacity to maintain their production.

The type of autoimmune disorder or disease that occurs and the amount of destruction done to the body that results depends on which systems or organs are targeted by the autoantibodies, and to what degree.

Organ specific autoantibodies that primarily target a single organ, (such as the thyroid in Graves’ disease and Hashimoto’s thyroiditis), are often the easiest to diseases diagnose as they frequently present with organ related symptoms. 

Disorders due to systemic autoantibodies can be much more difficult to diagnose.

Autoimmune disorders signs and symptoms 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 and anemia. 

Symptoms vary from person to person, vary over time, vary with organ involvement, and they may taper off or flare unexpectedly. 

A patient 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.

Diagnostic tests: 

blood tests to detect inflammation, autoantibodies, and organ involvement

x-rays and other imaging scans to detect changes in bones, joints, and organs

biopsies to look for pathologic changes in tissue specimens

Autoantibody tests are 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. 

The positive ANA test 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. 

Some autoimmune disorders, such as systemic lupus erythematosus (SLE) are 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. 

Patients with more than one autoimmune disorder may have several autoantibodies.

A many as 80% of those with SLE will have a positive double strand anti-double stranded DNA (anti-dsDNA) autoantibody test, and only about 25–30% will have a positive RNP. 

Some individuals with an autoimmune disorder have negative autoantibody test results, but at a later date the autoantibodies may develop.

Systemic autoantibody tests are used to:

Help diagnose systemic autoimmune disorders.

Help determine the degree of organ or system involvement and damage.

Monitor the course of the disorder and the effectiveness of treatments. 

Antibody profiling can identify people from forensic samples by analyzing the antibodies in body fluids. 

There is no prevention or cure for autoimmune disorders at this time. 

Treatment is used to alleviate symptoms and to help maintain body function.

Each person has a unique, individual set of antibodies, called individual specific autoantibodies found in blood, serum, saliva, urine, semen, perspiration, tears, and body tissues.

These autoantibodies are not affected by illness, medication, or food/drug intake. 

The sensitivity and specificity of various autoantibodies for a particular disease is different for different diseases.

Antinuclear antibodies Anti-SSA/Ro autoantibodies ribonucleoproteins systemic lupus erythematosus, neonatal heart block, primary Sjögren syndrome

Anti-La/SS-B autoantibodies Primary 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

Anti-p62 antibodies nucleoporin primary biliary cirrhosis

Anti-sp100 antibodies Sp100 nuclear antigen

Anti-glycoprotein-210 antibodies 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 GM1 multifocal motor neuropathy with conduction block (MMN)

Anti-actin antibodies actin Coeliac disease (antibody levels correlate with the level of intestinal damage, autoimmune hepatitis, gastric cancer

anti-CCP cyclic citrullinated peptide rheumatoid arthritis

Liver kidney microsomal type 1 antibody autoimmune hepatitis

Lupus anticoagulant Anti-thrombin antibodies thrombin systemic lupus erythematosus

Antiphospholipid antibodies 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

Anti-SRP signal recognition particle dermatomyositis

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

Anti-Yo Cerebellar 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-hemidesmosome hemidesmosomes Bullous pemphigoid

Anti-glomerular basement membrane basement membrane in lungs and kidneys

Goodpasture syndrome

Anti-parietal cell gastric parietal cells Pernicious anemia

Anti-intrinsic factor intrinsic factor Pernicious anemia

Anti-phospholipase A2 receptor phospholipase A2 receptor

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