ANTI-MITOCHONDRIAL AND ANTI-SMOOTH MUSCLE ANTIBODIES

CLINICAL UTILITY:

Autoantibodies to mitochondria and smooth muscle are associated with a variety of liver diseases, but the particular antibody and its serum titer can be useful in differential diagnosis. For example, anti-mitochondrial antibodies (AMA) are present in high titers in approximately 90% of patients with primary biliary cirrhosis, and present in lower titers in 7-30% of patients with chronic active hepatitis, but rarely found in extrahepatic jaundice.

When found in high titer, antibodies to smooth muscle (ASMA) suggest a diagnosis of chronic active hepatitis. Low titers of ASMA occur in acute infectious hepatitis, alcoholic cirrhosis, viral infections such as infectious mononucleosis, malignancies and occasionally in normal healthy individuals.

In some severe cases of chronic active hepatitis both anti-smooth muscle antibodies and anti-nuclear antibodies (homogeneous pattern) are present.

METHOD DESCRIPTION:

Indirect immunofluorescence is the method used to detect antibodies to mitochondria and smooth muscle. AMA are titered to end point on mouse kidney tissue, and ASMA are titered to 1:640 on mouse stomach tissue.

REFERENCE RANGE:

Negative. Low titers (1:10) may appear in a small percentage of the normal population.

SPECIMEN REQUIREMENTS:

0.5 ml serum. Freeze.