Autoantibodies
Autoantibodies (abbreviation: AAk ) are antibodies that bind the body's own antigen . Autoantibodies are a characteristic feature of autoimmune diseases , but can also be detected, for example, in cancer or in diseases that are associated with a chronic loss of body cells . They can either be causally involved in the development of the disease, influence the course or only occur as an accompanying phenomenon without relevance to the clinical picture. For a number of autoimmune diseases, the role of the autoantibodies identified is controversial or not yet fully understood.
Autoantibodies are of particular interest for diagnostic purposes . On the one hand, they make it possible to confirm a suspected diagnosis in the case of non-specific symptoms. In addition, their detection can also be used to support the differential diagnosis between different forms of a disease, such as the distinction between type 1 and type 2 diabetes. Autoantibodies are an important diagnostic parameter for monitoring the progress of some diseases. Predictive diagnostics based on the detection of specific autoantibodies before clinical symptoms appear is also possible for some diseases. However, some autoantibodies occur in various diseases, so that further parameters are necessary for a specific diagnosis in this case.
Therapeutic approaches aimed at suppressing or reducing autoantibodies are in clinical trials for some diseases.
Examples
Rheumatoid factors are immunoglobulins that are directed against the Fc part of IgG . They are often found in people with rheumatoid arthritis . Although high titers correlate with the severity of the disease, they are not specific. Rheumatoid factors are also found in infections. There are different test methods.
Antinuclear antibodies (ANA) are autoantibodies that occur primarily in collagenosis and are directed against intranuclear antigens.
Anti- DNA antibodies can be directed against double-stranded (ds) DNA and single-stranded (ss) DNA. Anti-double-stranded DNA antibodies are relatively specific for systemic lupus erythematosus and usually correlate with the course of the disease.
| Autoimmune disease | Autoantibodies | Antigens |
|---|---|---|
| Rheumatoid arthritis | Rheumatoid factor | Immunoglobulin G Fc part |
| Graves disease | Thyroid Receptor Autoantibodies (TRAK) | Thyrotropin receptor |
| Myasthenia gravis | Anti- acetylcholine receptor | Acetylcholine receptor |
| Systemic lupus erythematosus | Anti-double-stranded DNA Anti-Sm |
Double-stranded DNA Sm ribonucleoprotein |
| drug-induced lupus erythematosus | Anti-histone | Histones |
| Goodpasture Syndrome | Anti-type IV collagen | Type IV collagen |
| Scleroderma | Anti-scl-70 | DNA topoisomerase |
| CREST syndrome | Anti-centromere | Centromere proteins A, B and C |
| Polymyositis / dermatomyositis | Anti-yo-1 | Histidyl synthetase |
| Granulomatosis with polyangiitis | Anti-proteinase 3 | Proteinase 3 |
| Pemphigus vulgaris | Anti-plakoglobin, anti-desmoglein III | Plakoglobin, desmoglein III |
| Sjogren's syndrome | Anti-SS-A (Ro), Anti-SS-B (= La) | Ribonucleoprotein |
| Type 1 diabetes mellitus | IAA ICSA GADA ZnT8A IA-2A (synonym: ICA512) |
Insulin islet cell surface antigens glutamate decarboxylase (mainly GAD65, but also GAD67) zinc transporter 8 tyrosine phosphatase IA-2 |
| Primary biliary cholangitis | Antimitochondrial Antibodies (AMA) | E2 subunit of the pyruvate dehydrogenase complex (PDH-E2) |
| Celiac disease | ARA EMA Anti-tTG |
Reticulin Endomysium Tissue Transglutaminase |
| Kawasaki syndrome | Endothelial Cell Antibodies (AECA) | Medium-sized vessel endothelial cells |
literature
- Karsten Conrad, Werner Schößler, Falk Hiepe: Autoantibodies in systemic autoimmune diseases. A diagnostic guide. Series: Immundiagnostic Library of the Society for the Promotion of Immundiagnostics. Third edition. Pabst Science Publishers, Lengerich, Berlin, Bremen and others 2006, ISBN 3-89967-350-6
- Karsten Conrad, Werner Schößler, Falk Hiepe: Autoantibodies in organ-specific autoimmune diseases. A diagnostic guide. Series: Immundiagnostic Library of the Society for the Promotion of Immundiagnostics. Pabst Science Publishers, Lengerich, Berlin, Bremen and others 2010, ISBN 3-89967-688-2
- Yehuda Shoenfeld (Ed.), M. Eric Gershwin (Ed.), Pier Luigi Meroni (Ed.): Autoantibodies. Second edition. Elsevier, Amsterdam and Boston 2007, ISBN 0-444-52763-X
- Kenneth M. Pollard (Ed.): Autoantibodies and Autoimmunity. Molecular Mechanisms in Health and Disease. Wiley-VCH, Weinheim 2006, ISBN 3-527-31141-6
Web links
- http://www.onmeda.de/laborwerte/rheumafaktor.html
- Entry on rheumatoid factor in Flexikon , a Wiki of the DocCheck company
