[Heterogeneity of antimicrosomal autoantibodies in chronic hepatitis C virus infection and delta hepatitis].
Microsomal antigen autoantibodies are typical of type 2 autoimmune hepatitis, and a strong association with chronic hepatitis C virus (HCV) infection has been reported in certain geographical areas. These autoantibodies have been denominated LKM-1 to differentiate them from those associated with thienylic acid-induced hepatitis (LKM-2) and from those seen in patients with chronic delta hepatitis (LKM-3). To investigate the antigenic specificity of autoantibodies associated with chronic hepatitis C and delta, we analyzed 52 LKM-1 positive serum samples from patients with chronic hepatitis C and 17 LKM-3 positive serum samples from patients with chronic delta hepatitis by indirect immunofluorescence and Western blotting (immunoblotting). Reactivity of subjects with chronic hepatitis C was heterogeneous: only 5 out of 52 LKM-1 positive patients, tested by Western blot, recognized a single protein of 50 kD, previously identified by Manns et al. with an immunogenic epitope of cytochrome P450IID6. Thirteen of the 52 patients also reacted with a 70 kD microsomal protein, and 12 out of 52 reacted only with a 59 kD protein. Twenty-two sera, notwithstanding the high titer in immunofluorescence, did not evidence any reactivity when tested by Western blot. The same sera tested positive in LKM-1 ELISA when solubilized human microsomal proteins were used. Fourteen out of 17 LKM-3 positive sera from patients with chronic hepatitis delta recognized a 55 kD microsomal protein in Western blot; three sera, HCV and HIV positive, did not react with any protein by Western blot. None of these sera was positive in ELISA LKM-1.(ABSTRACT TRUNCATED AT 250 WORDS)
Durazzo
M
M
Istituto di Medicina Interna, Università degli Studi di Torino.
Costa
C
C
Schmidt
E
E
Loges
S
S
Scaglione
L
L
Touscoz
A G
AG
Smedile
A
A
Manns
M P
MP
Rizzetto
M
M
Pagano
G
G
D000918:Antibody Specificity; D001323:Autoantibodies / Q000032:analysis*; D015153:Blotting, Western; D002908:Chronic Disease; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D005260:Female; D005455:Fluorescent Antibody Technique; D006526:Hepatitis C / Q000276:immunology*; D003699:Hepatitis D / Q000276:immunology*; D006801:Humans; D007668:Kidney / Q000276:immunology; D008297:Male; D008861:Microsomes / Q000276:immunology*; D008862:Microsomes, Liver / Q000276:immunology
D001323:Autoantibodies; D000939:Epitopes