We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What are Antimitochondrial Antibodies?

By Caitlin Kenney
Updated May 17, 2024
Our promise to you
WiseGeek is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At WiseGeek, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Antimitochondrial antibodies (AMA) are autoantibodies, or antibodies against the self, that target mitochondria. A mitochondrion is an organelle, or a structure within a cell, that helps to manufacture cellular energy, monitor cell growth, and cause cell death, amongst other functions. An antibody is a protein called an immunoglobulin that works with the immune system to locate and disarm damaged cells and foreign objects, such as viruses or harmful bacteria. In a healthy patient, the immune system provides several crucial defense mechanisms for the body, but when the immune system mistakenly turns against healthy tissues in the body, it can cause serious illnesses known as autoimmune disorders. The presence of antimitochondrial antibodies in the blood indicates an autoimmune disease, such as primary biliary cirrhosis (PBC), rheumatoid arthritis, autoimmune hepatitis, systemic lupus erythematosus, or thyroiditis.

An antibody is a protein composed of two heavy polypeptide chains and two light polypeptide chains that form a “Y” shape. The trunk of the “Y” is the constant region, of which there are five classes, or isotypes, that control how the antigen is destroyed and how the immune system should respond. An antigen is the target of the antibody, or mitochondria in the case of antimitochondrial antibodies. The two arms of the “Y” form the variable regions of the antibody, which include hypervariable regions and antigen binding sites. The antigen binding sites are specially formed, either through random composition or in response to an immune reaction, to recognize a very specific antigen, then bind to it and destroy it.

In a healthy body, a mechanism called immune tolerance prevents the body from attacking certain antigens, such as the body’s healthy tissue. Antibodies that fail to recognize self and try to attack healthy tissue are removed from the system. Some external antigens, or non-self antigens, such as an organ transplant or a fetus in a pregnant woman, require an immune system mechanism called acquired tolerance.

The presence of antimitochondrial antibodies in the body’s fluids implies that the immune system has lost its tolerance of mitochondria, or lost its ability to recognize mitochondria as part of the self. These antibodies then target a protein found on an enzyme complex, called pyruvate dehydrogenase complex- enzyme 2 (PDC-E2), in the inner lining of mitochondria. Oftentimes, mitochondria in the liver are most affected.

Autoimmune hepatitis occurs when the immune system attacks the liver, causing inflammation, or swelling, and cirrhosis at late stages. Cirrhosis refers to the scarring of liver tissue, which may lead to impaired liver function. Autoimmune hepatitis presents symptoms of dark urine, pale stool, fatigue, loss of appetite, general itching sensation, nausea, and abdominal swelling and usually arises in young females with family history of the disease. A positive blood test for antimitochondrial antibodies, amongst other signs, is often used to diagnose this disease.

The AMA blood test may also be used to diagnose primary biliary cirrhosis (PBC). For unknown causes, PBC irritates the bile ducts in the liver, causing inflammation, and then blocking of the bile ducts. This obstruction then causes cell damage in the liver and eventually cirrhosis. This disease primarily arises in middle-aged females and presents symptoms of jaundice, belly pain, itching, abdominal swelling, fatty stools, and collection of fat under the skin.

WiseGeek is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.

WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.