Characterization of anti-liver-kidney microsome antibody (anti-LKM1) from hepatitis C virus-positive and -negative sera.
BACKGROUND
Hepatitis C virus-related antibodies were found in sera positive for antibodies to liver/kidney microsome antibody, usually considered a marker of autoimmune hepatitis. The aim of this study was to analyze the specificity of this autoantibody in sera from patients with and without hepatitis C virus infection.


METHODS
Fifteen anti-hepatitis C virus- and anti-liver kidney microsome-positive sera were compared with 11 sera from patients with autoimmune hepatitis, for reactivity against rat and human liver microsomal proteins, P450IID6 recombinant proteins, and various synthetic peptides spanning the 241-429 amino acids sequence of the P450IID6.


RESULTS
Ten of 11 sera from patients with autoimmune hepatitis bound to recombinant proteins spanning the P450IID6 region between amino acids 72 and 458. These sera bound to the 254-271 peptide, and some also recognized the 321-351, 373-389 and 410-429 peptides. Four of 15 antihepatitis C virus recognized the fusion protein coded by the full-length P450IID6 complementary DNA; 3 of them also reacted with the P450IID6 region between amino acids 72-456. Only 1 sera recognized the 321-351 peptide.


CONCLUSIONS
P450IID6 antigenic sites recognized by anti-hepatitis C virus-positive sera were different from those recognized by sera from patients with autoimmune hepatitis.
Yamamoto
A M
AM
INSERM U347, Hôpital de Bicêtre, Kremlin, France.
Cresteil
D
D
Homberg
J C
JC
Alvarez
F
F
D000293:Adolescent; D000328:Adult; D000818:Animals; D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000175:diagnosis; D002648:Child; D002675:Child, Preschool; D019389:Cytochrome P-450 CYP2D6; D003577:Cytochrome P-450 Enzyme System / Q000276:immunology; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D016174:Hepacivirus / Q000276:immunology*; D006505:Hepatitis / Q000175:diagnosis; D006508:Hepatitis Antibodies / Q000097:blood*; D006526:Hepatitis C / Q000175:diagnosis / Q000276:immunology*; D018937:Hepatitis C Antibodies; D006801:Humans; D006899:Mixed Function Oxygenases / Q000276:immunology; D010446:Peptide Fragments / Q000276:immunology; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000276:immunology
D001323:Autoantibodies; D006508:Hepatitis Antibodies; D018937:Hepatitis C Antibodies; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; C060729:anti-liver kidney microsome antibody; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D019389:Cytochrome P-450 CYP2D6