LKM-1

Product Information

Liver/kidney microsomal antigen type 1 (LKM-1) is an important diagnostic marker for autoimmune hepatitis, specifically for autoimmune hepatitis type 2 (AIH2). AIH2 is an autoimmune disease that mostly affects young people and children. It is rarer than type 1 autoimmune hepatitis (AIH1) and regarded as the more severe form of AIH. While AIH1 is characterized by anti-nuclear (ANA) and anti-smooth muscle (ASMA) antibodies, AIH2 is defined by the presence of LKM-1 as well as anti-liver cytosol type 1 (LC1) autoantibodies or in some cases anti-LC-1 autoantibodies alone.

LKM-1 antibodies may also be present occasionally in patients with chronic hepatitis C, but evidence suggests they target different epitopes on the antigen. The antigenic target of anti-LKM-1 autoantibodies has been identified as Cytochrome P450 2D6 (CYP2D6), a mono oxygenase and member of the cytochrome P450 superfamily of enzymes. This enzyme plays another significant role in the medical field due to its involvement in the metabolism of about 25% of frequently prescribed pharmaceuticals, as well as steroids and other xenobiotic substances. CYP2D6 is a membrane anchored, heme containing enzyme with a characteristic P450 fold. The membrane spanning region is located on the N-terminus, the epitopes and the immunodominant region are located in the C-terminal region of the protein.

AROTEC LKM-1 is a truncated, soluble form of the human Cytochrome P450 2D6 enzyme, lacking the short 22-amino-acid N-terminal transmembrane domain. The large soluble P450 domain contains a heme cofactor and gives the antigen its characteristic pale pink color. LKM-1 is produced in insect cells using the Baculovirus expression system.

Clinical Indications

Autoimmune Hepatitis

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MSDS

References

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