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.
DESIGN: Cross-sectional.
SETTING: University-based hospital.
PATIENTS: 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: