[Clinical significance of antibody to Y19 protein in nonA and nonB chronic liver disease].
Antibody against the recombinant protein Y19 deriving from non-structural region 3 (NS3) of the hepatitis C virus (HCV) genome was measured in the serum from 300 patients with nonA-nonB chronic liver disease including serial serum samples from these patients by using an enzyme linked immuno-sorbent assay. Simultaneously, antibodies to a synthetic core peptide (AR142) and the recombinant peptide of NS 3-4 region (C-100) were tested. Anti-Y19 antibody was detected in 83.3%, 65.2% and 76.6% of patients with nonA-nonB chronic hepatitis (n = 144), liver cirrhosis (n = 46) and hepatocellular carcinoma (n = 43), respectively. In sera of other chronic liver disease, the detection rate of anti-Y19 antibody was significantly low comparing to nonA-nonB chronic liver disease. Positive rates of the patients for AR142 antibody and C-100 antibody were similar to the one for Y19 antibody. Patients positive for Y19 antibody have a tendency to be positive for C-100 antibody. Serum Y19 antibody level during and after treatment with natural interferon alpha (IFN-alpha; 5MU, 24 weeks) was studied in 33 patients with chronic hepatitis C. The effectiveness of IFN therapy did not correlate with the Y19 antibody level before the treatment. In most cases Y19 antibody level decreased relating to the improvement of the serum ALT level during the treatment. Y19 antibody level declined not only during IFN treatment but after the treatment in Responder group (as assessed by normal ALT for 6 months after the treatment; n = 14). Whereas, in Non-responder group (the rest of Responder group; n = 16) Y19 antibody level was maintained to the level at the end of the treatment or elevated again to the level before the treatment. In Responder group, 6 of 7 cases in whose serum HCV-RNA disappeared at 6 months after the treatment, had decrease of Y19 antibody to less than 20% of the pretreatment level and Y19 antibody became undetectable in 4 cases at 6 months after the treatment. One case in whom Y19 antibody did not decrease by the treatment had an increase of serum ALT level and a relapse of the disease at 12 months after the treatment. 5 of 6 cases in "Responder" group that HCV-RNA remained positive had more than 20% of Y19 antibody level of the pretreatment level at 6 months after the treatment. Therefore the decrease of Y19 antibody level was closely related to the efficacy in terms of serum ALT level and HCV-RNA level.(ABSTRACT TRUNCATED AT 400 WORDS)
Sakashita
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Second Department of Internal Medicine, Faculty of Medicine, Kagoshima University.
D000595:Amino Acid Sequence; D001483:Base Sequence; D002908:Chronic Disease; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D016174:Hepacivirus / Q000235:genetics / Q000276:immunology; D006508:Hepatitis Antibodies / Q000097:blood*; D006526:Hepatitis C / Q000276:immunology* / Q000628:therapy; D018937:Hepatitis C Antibodies; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins; D000637:Transaminases / Q000097:blood; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000276:immunology*
D006508:Hepatitis Antibodies; D018937:Hepatitis C Antibodies; D016898:Interferon-alpha; D011994:Recombinant Proteins; D017361:Viral Nonstructural Proteins; C081875:Y19 protein, Hepatitis C virus; D000637:Transaminases