Differences in immune recognition of cytochrome P4502D6 by liver kidney microsomal (LKM) antibody in autoimmune hepatitis and chronic hepatitis C virus infection

Clin Exp Immunol. 1994 Jul;97(1):94-9. doi: 10.1111/j.1365-2249.1994.tb06585.x.


LKM-1 antibody, which characterizes a subtype of autoimmune hepatitis (AIH), is also found in some patients with chronic hepatitis C virus (HCV) infection. It has been suggested that HCV initiates autoimmunity through molecular mimicry, because there is partial identity between HCV and cytochrome P4502D6 (CYP2D6), the putative target of LKM-1. Whether CYP2D6 is the target of LKM-1 in HCV-related liver disease, however, is controversial. To clarify this issue, we have studied by phage plaque assay and Western blot the reactivity to recombinant CYP2D6, isolated from a human liver cDNA library, in 55 patients with LKM-1, 18 (14 females, median age 12 years) anti-HCV-negative, with classical AIH, and 37 (27 females, median age 52 years) anti-HCV-positive. Reactivity to CYP2D6 was found in 72% of the anti-HCV-negative, but only in 27% of the anti-HCV-positive patients (P < 0.001), although immunofluorescence LKM-1 titres were similar in the two groups. In addition, to investigate whether the antibody responsible for the LKM-1 fluorescent pattern also reacts with CYP2D6, we have determined the specificity of LKM-1 antibodies present in the supernatant of lymphoblastoid B cell lines obtained from two patients with LKM-1-positive AIH. An oligo/monoclonal antibody thus generated gave both the typical fluorescent pattern and reacted with CYP2D6. Our results show that whilst antibodies producing the characteristic LKM-1 fluorescent pattern can react with CYP2D6, not all LKM-1-positive sera do so, particularly if obtained from patients with chronic HCV infection. This suggests that LKM-1 in HCV infection recognizes epitopes or antigens different from those targeted in AIH.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Antibody Specificity
  • Autoantibodies / blood*
  • Autoantigens
  • Autoimmune Diseases / immunology*
  • B-Lymphocytes / immunology
  • Child
  • Child, Preschool
  • Cytochrome P-450 CYP2D6
  • Cytochrome P-450 Enzyme System / immunology*
  • Female
  • Hepatitis / immunology*
  • Hepatitis C / immunology*
  • Hepatitis, Chronic / immunology*
  • Humans
  • Infant
  • Male
  • Middle Aged
  • Mixed Function Oxygenases / immunology*
  • Recombinant Fusion Proteins / immunology


  • Autoantibodies
  • Autoantigens
  • Recombinant Fusion Proteins
  • anti-liver kidney microsome antibody
  • Cytochrome P-450 Enzyme System
  • Mixed Function Oxygenases
  • Cytochrome P-450 CYP2D6