title: Detection of hepatitis C virus antibody in the absence of viral RNA in patients with autoimmune hepatitis.
abstract: OBJECTIVE
  To determine whether laboratory findings showing antibodies to hepatitis C virus (HCV) in patients with autoimmune hepatitis represent false-positive results and to identify possible explanations for true-positive results in these patients.
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  University-based hospital.
  
  
  METHODS
  Fifty-two patients with non-A, non-B chronic hepatitis as a control group and 26 patients with classic chronic active autoimmune hepatitis.
  
  
  METHODS
  Comparison of the results of five kinds of assays of HCV antibodies and HCV RNA.
  
  
  RESULTS
  Of 52 patients with non-A, non-B chronic hepatitis, HCV antibodies (anti-HCV) were detected in 42 patients (81%; 95% CI, 67% to 90%) by a first-generation enzyme-linked immunosorbent assay (ELISA-I), in 39 patients (75%) by Sp42 ELISA, in 37 patients (71%) by RIA-I, in 49 patients (94%) by ELISA-II, and in 48 patients (92%) by RIBA-II. We found HCV RNA in 47 patients (90%; CI, 79% to 97%). Of the 26 patients with autoimmune hepatitis, anti-HCV were detected in 23 patients (88%; CI, 70% to 98%) by ELISA-I, in 12 (46%) by both RIA-I and Sp42 ELISA, in 20 (77%) by ELISA-II, and in 9 (35%) by RIBA-II. However, HCV RNA was found in only five of these patients (19%; CI, 7% to 39%). None of our patients, including controls, had antibodies to superoxide dismutase. Of the 21 patients who had autoimmune hepatitis that was completely responsive to steroid therapy, 18 had anti-HCV by ELISA-I, but 13 of these patients had negative results by RIBA-II, and only two patients had HCV RNA. Of the five patients who did not respond to steroid treatment, all had anti-HCV by ELISA-I, four had negative results by RIBA-II, and three had HCV RNA.
  
  
  CONCLUSIONS
  Testing for HCV antibodies in patients with autoimmune hepatitis frequently elicits positive results when the ELISA-I or ELISA-II tests are used. Most of these appear to represent false-positive results because HCV RNA is usually absent from the serum. Such false positivity may result from previous infection with HCV or from cross-reaction of an epitope of HCV. Other patients with apparent autoimmune hepatitis who fail to respond to corticosteroid therapy may actually have chronic hepatitis C (or other non-A, non-B hepatitis) infection.
authors.affiliation: Osaka City University Medical School, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nishiguchi
authors.forename: T
authors.initials: T
authors.lastname: Kuroki
authors.forename: T
authors.initials: T
authors.lastname: Ueda
authors.forename: K
authors.initials: K
authors.lastname: Fukuda
authors.forename: T
authors.initials: T
authors.lastname: Takeda
authors.forename: S
authors.initials: S
authors.lastname: Nakajima
authors.forename: S
authors.initials: S
authors.lastname: Shiomi
authors.forename: K
authors.initials: K
authors.lastname: Kobayashi
authors.forename: S
authors.initials: S
authors.lastname: Otani
authors.forename: N
authors.initials: N
authors.lastname: Hayashi
mesh_terms: D000328:Adult; D000368:Aged; D001327:Autoimmune Diseases / Q000276:immunology* / Q000382:microbiology; D001483:Base Sequence; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005189:False Positive Reactions; D005260:Female; D016174:Hepacivirus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D006505:Hepatitis / Q000276:immunology* / Q000382:microbiology; D006508:Hepatitis Antibodies / Q000097:blood*; D006526:Hepatitis C / Q000276:immunology; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D012367:RNA, Viral / Q000097:blood*; D011863:Radioimmunoassay; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity
chemical_list: D006508:Hepatitis Antibodies; D012367:RNA, Viral; D011933:Reagent Kits, Diagnostic