What is Anti LKM-1 (Liver Kidney Microsomes) Antibody?

Also Known As: Liver Kidney Microsomal Type 1 Antibodies, LKM1 Antibodies, Anti-Liver/Kidney Microsomal Antibodies Type 1, Anti-LKM1, Anti-P450 2D6 Antibody

Formal Name: Liver Kidney Microsome Type 1 Antibodies (Cytochrome P450 2D6 Antibodies)

Liver kidney microsome type 1 (anti-LKM-1) antibodies are autoantibodies, proteins produced by the body’s immune system that recognize and target its own enzyme called cytochrome P450 2D6 (CYP2D6), a protein found primarily in liver cells. The development of anti-LKM-1 antibodies is strongly associated with type 2 autoimmune hepatitis. This test detects and measures the amount (titer) of anti-LKM-1 (or antibody against CYP2D6) in the blood.

Autoimmune hepatitis is an acute or chronic inflammation of the liver that can lead to liver cirrhosis and, in some cases, to liver failure. It is hepatitis that is not due to another identifiable cause, such as a viral infection, exposure to a drug or toxin, a hereditary disorder, or alcohol abuse. Anyone can develop the disorder, but the majority of those affected are women.

There is general agreement that there are two main types of autoimmune hepatitis (debate continues as to whether there is a distinct third type). Type 1 is the most common form of autoimmune hepatitis in the United States and is associated with the presence of smooth muscle antibodies (SMA) in the blood. Type 2 is less common and tends to be more severe. It is associated with anti-LKM-1 antibodies and primarily affects young girls and is more common in Europe than in the United States.

How is it used?

The liver-kidney microsome type 1 antibody (anti-LKM-1 or CYP2D6 antibody) test is primarily used along with a smooth muscle antibody (SMA) and an antinuclear antibodies (ANA) test to help diagnose autoimmune hepatitis and to differentiate between the two major types, type 1 and type 2.

These tests may be used to follow up on abnormal liver test findings, such as persistently increased alanine aminotransferase (ALT), aspartate aminotransferase (AST), or bilirubin. Additional tests may be ordered, such as immunoglobulins, as these may be increased with autoimmune hepatitis and/or hepatitis B and/or hepatitis C, to rule out viral hepatitis.

When is it ordered?

The anti-LKM-1 test may be ordered when a healthcare practitioner is investigating an individual’s liver disease and wants to distinguish between different causes of liver injury. It may be ordered along with other testing, such as an SMA and ANA test. These tests are usually ordered when a person presents with signs and symptoms, such as fatigue, weakness, and jaundice, and has abnormal findings on routine liver tests.

Signs and symptoms associated with autoimmune hepatitis may also include:

• Itching
• An enlarged liver
• Joint aches
• Abdominal discomfort
• Abnormal blood vessels in the skin (spider angiomas)
• Nausea or vomiting
• Dark urine
• Loss of appetite
• Pale or clay-colored stools
• Muscle pain (myalgia)
• In women, lack of menstrual periods (amenorrhea)
• Skin rashes
• Fluid buildup (edema)

Many of these signs and symptoms are not specific to autoimmune hepatitis; they are also seen with other causes of liver injury and with other conditions.