title: Liver/kidney microsomal antibody type 1 and liver cytosol antibody type 1 concentrations in type 2 autoimmune hepatitis.
abstract: BACKGROUND
  Liver/kidney microsomal antibody type 1 (LKM1) and liver cytosol antibody type 1 (LC1) are the serological markers of type 2 autoimmune hepatitis (AIH).
  
  
  OBJECTIVE
  Since LKM1 and LC1 react against two distinct liver specific autoantigens (cytochrome P450IID6 (CYP2D6) and a 58 kDa cytosolic polypeptide respectively), the aim was to see whether LKM1 and LC1 concentrations correlate with liver disease activity.
  
  
  METHODS
  Twenty one patients with type 2 AIH were studied.
  
  
  METHODS
  All sera were tested by indirect immunofluorescence, counterimmunoelectrophoresis, and immunoblotting visualised by enhanced chemiluminescence. To evaluate LKM1 and LC1 levels, the 50 kDa microsomal reactivity (corresponding to CYP2D6) and the 58 kDa cytosolic reactivity were quantified by densitometric analysis.
  
  
  RESULTS
  Seven patients were positive for LKM1, nine for LC1, and five for both. Serial serum samples at onset and during immunosuppressive treatment were analysed in 13 patients (four positive for LKM1, six positive for LC1 and three positive for both). During remission, LKM1 concentration remained essentially unchanged in six of seven patients, and decreased in only one. Conversely, in two of nine patients, LC1 was completely lost, and, in the remaining seven, LC1 concentration was reduced by more than 50%. After immunosuppression tapering or withdrawal, flare ups of liver necrosis ensued with increasing LC1 concentration, but not LKM1.
  
  
  CONCLUSIONS
  LC1 concentration, at variance with that of LKM1, parallels liver disease activity, and its participation in the pathogenic mechanisms of liver injury can be hypothesised.
authors.affiliation: Department of Internal Medicine, Cardioangiology and Hepatology, University of Bologna, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Muratori
authors.forename: M
authors.initials: M
authors.lastname: Cataleta
authors.forename: P
authors.initials: P
authors.lastname: Muratori
authors.forename: M
authors.initials: M
authors.lastname: Lenzi
authors.forename: F B
authors.initials: FB
authors.lastname: Bianchi
mesh_terms: D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003378:Counterimmunoelectrophoresis; D003720:Densitometry; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D019693:Hepatitis, Autoimmune / Q000276:immunology* / Q000628:therapy; D006801:Humans; D015151:Immunoblotting; D007165:Immunosuppression Therapy; D007223:Infant; D008297:Male
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; C094307:anti-liver cytosolic protein 1; C060729:anti-liver kidney microsome antibody