Liver Diseases

M2 Antibodies | LKM 1 Antibodies

 

M2 Antibodies

Product Article No. No. of tests
Varelisa M2 Antibodies  147 96  96 tests

Antigens

Mitochondrial autoantigens are subunits of the 2-oxo acid dehydrogenase complexes and are located in the inner mitochondrial membrane of eukaryotic cells. The primary function of the 2-oxo acid dehydrogenase complex is channeling electrons via oxidative decarboxylase reactions. Today one distinguishes nine different AMA-subclasses (M1 to M9), of which M2 is the most important one as a marker for primary biliary cirrhosis (PBC). M2 antibodies recognize components of the enzyme pyruvate dehydrogenase (PDH). The antigens (approx. 74, 52, 45 and 39 kDa) are ubiquitous, namely in mammalian and yeast mitochondria, as well as in bacteria and chloroplasts. Three of the four M2 antigens are E2 enzymes, which catalyze the transfer of the respective decarboxylated residue from the E1-enzyme (decarboxylase) to coenzyme A. The fourth M2-component is represented by protein X, which is found in association with PDH.

The Varelisa M2 Antibodies assay uses purified pyruvate dehydrogenase.

Antibody specificity and prevalence

Primary Biliary Cirrhosis, PBC (96%), differential diagnosis to autoimmune hepatitis.

Information about Primary Biliary Cirrhosis

Disease activity

AMA concentrations do not correlate with disease stages and prognosis. The effects of drug therapy on AMA levels are limited.

When is the measurement recommended?

  • Suspicion of Primary Biliary Cirrhosis (PBC)

Antibody isotype

IgG

References

  • Leung PSC, Coppel RL, Gershwin E (1996) Mitochondrial autoantibodies. In: Peter JB, Shoenfeld Y (eds.) Autoantibodies, pp 53-60, Elsevier, Amsterdam 
  • Baum H (1995) Mitochondrial antigens, molecular mimicry and autoimmune disease. Biochim Biophys Acta - Mol Basis Dis 1271, 111-121 
  • Berg PA, Klein R (1992) Antimitochondrial antibodies in primary biliary cirrhosis and other disorders: definition and clinical relevance. Dig Dis 10, 85-101

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LKM 1 Antibodies

Product Article No. No. of tests
Varelisa LKM 1 Antibodies 175 96 96 tests

Antigens

Liver/kidney microsomal (LKM) antibodies are characterized using indirect immunofluorescence by their reaction with the cytoplasm of hepatocytes and proximal, but not distal, renal tubules. Anti-LKM 1 antibodies react with the 50 kDa cytochrome P 450 II D6, which is one of at least 15 human hepatic P450 isozymes involved in phase I drug metabolism.

The Varelisa LKM 1 Antibodies assay uses human, recombinant cytochrome P450 II D6.

Antibody specificity and prevalence

  • Autoimmune Hepatitis type II (100%, because AIH type II is characterized by positive LKM 1) 
  • Chronic Hepatitis C (7%) 
  • Halothane Hepatitis (very rare)

Disease activity

LKM 1 antibody concentration do not correlate with disease stages.

When is the measurement recommended?

Suspicion of Autoimmune Hepatitis

Antibody isotypes

IgG

References

  • Manns MP (1996) Liver/kidney microsomal autoantibodies. In: Peter JB, Shoenfeld Y (eds.) Autoantibodies, pp 53-60, Elsevier, Amsterdam 
  • Obermayer Straub P, Strassburg CP, Manns MP (2000) Autoimmune hepatitis. J Hepatol 32 Suppl. 1, 181-197 
  • Mann MP, Rambusch EG (1996) Diagnosis of autoimmune hepatitis. Dtsch Med Wochenschr 121, 1503-1507

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