Antimitochondrial antibodies are a very specific and sensitive marker of primary biliary cirrhosis, a chronic autoimmune disease.
Antimitochondrial antibodies( AMA , anti-mitochondrial antibodies) are autoantibodies directed against mitochondrial proteins. They were first described in 1956 in a patient with primary biliary cirrhosis of the liver.
Contents:
- Antimitochondrial antibodies - types
- Antimitochondrial antibodies - indications for the test
- Antimitochondrial antibodies - what is the test?
- Antimitochondrial antibodies - how to interpret the result?
Primary biliary cirrhosis is an autoimmune disease that mainly affects women and involves the destruction of the intrahepatic bile ducts caused by the presence of, among others, anti-mitochondrial antibodies directed mainly against the E2 component of the pyruvate dehydrogenase complex, which is located in the inner membrane of the mitochondria.
Antimitochondrial antibodies - types
There are several types of anti-mitochondrial antibodies:
- M1 - against cardiolipin (ACA)
- M2 - against alpha-ketoglutarate dehydrogenase
- M3 - against the outer mitochondrial membrane
- M4 - against sulfite oxidase
- M5, M6, M8 - against proteins of the outer mitochondrial membrane
- M7 - against sarcosine dehydrogenase
- M9 - against glycogen phosphorylase
Anti-mitochondrial antibodies M2 and M9 are considered to be the most specific for primary biliary cirrhosis. Other types of antibodies may be present, for example, in systemic lupus erythematosus.
Antimitochondrial antibodies - indications for the test
Antimitochondrial antibody testing is ordered together with other autoantibodies (e.g., antinuclear antibodies) in suspected primary biliary cirrhosis.
Symptoms of the disease include chronic fatigue and itchy skin. Untreated primary biliary cirrhosis leads tocirrhosis of the liver.
Antimitochondrial antibodies are a sensitive and specific marker of this disease and are present in 90-95% of patients.
Antimitochondrial antibodies - what is the test?
For the determination of anti-mitochondrial antibodies, blood collected from the elbow flexion is fasted. The level of anti-mitochondrial antibodies is determined by immunological methods. The most common type of immunofluorescence is indirect immunofluorescence.
After confirming the presence of anti-mitochondrial antibodies in the tested sample, the antibody titer is determined, i.e. the highest dilution of the serum, in which the presence of antibodies can be detected.
Antimitochondrial antibodies - how to interpret the result?
A positive result is the presence of an antibody titre greater than 1:40. Serological testing for anti-mitochondrial antibodies is part of a complex diagnostic process, and a positive result must always be interpreted in the context of the clinical picture and the presence of the characteristic symptoms of the disease.
About the author
Karolina Karabin, MD, PhD, molecular biologist, laboratory diagnostician, Cambridge Diagnostics Polska A biologist by profession, specializing in microbiology, and a laboratory diagnostician with over 10 years of experience in laboratory work. A graduate of the College of Molecular Medicine and a member of the Polish Society of Human Genetics. Head of research grants at the Laboratory of Molecular Diagnostics at the Department of Hematology, Oncology and Internal Diseases of the Medical University of Warsaw. She defended the title of doctor of medical sciences in the field of medical biology at the 1st Faculty of Medicine of the Medical University of Warsaw. Author of many scientific and popular science works in the field of laboratory diagnostics, molecular biology and nutrition. On a daily basis, as a specialist in the field of laboratory diagnostics, he runs the content department at Cambridge Diagnostics Polska and cooperates with a team of nutritionists at the CD Dietary Clinic. He shares his practical knowledge on diagnostics and diet therapy of diseases with specialists at conferences, training sessions, and in magazines and websites. She is particularly interested in the influence of modern lifestyle on molecular processes in the body.
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