[Clinical significance of N-14 antibody (ELISA) in diagnosis of non-A, non-B liver disease].Fukuoka Igaku Zasshi 1992; 83(4):156-67FI
In 1987 Chiron Co. in USA and Arima et al. in Japan reported successful isolation of clones coding peptides specific for non-A, non-B hepatitis infection. Hepatitis C virus (HCV) genome reported by the Chiron is supposed to have structural proteins of core, matrix, envelope and non-structural proteins of NS 1-5 from 5' to 3' end. C-100 antibody of which antigen is derived from the NS 3-4 region of the HCV genome is used generally, it is not sufficient to diagnose hepatitis C. On the other hand, the nucleotide and amino acid sequences in the epitope of N-14 clone established by Arima et al. have homology to those of core region of the HCV genome. Usually there are some mutation in sequences of HCV genome, but there is little mutation in 5' non-coding region and core protein area. Therefore we could diagnose hepatitis C more exactly by using N-14 antibody. In the present study N-14 antibody was determined in 871 healthy subjects and 285 cases with liver diseases by an ELISA. 1.6% of healthy subjects and 70-75% of cases with non-A, non-B chronic liver diseases are positive for N-14 antibody. In acute non-A, non-B hepatitis, 33.3% of sporadic cases and 75.0% of post-transfusion cases are positive for the test. As only 2 of 100 cases with other liver diseases are positive for the test, the N-14 antibody test seems to be highly sensitive and specific for the non-A, non-B hepatitis virus infection. These 1156 cases were tested for the C-100 antibody as well. No much difference between the results by using these tests, 15-20% of discrepancy between the tests, has been observed. In conclusion hepatitis C can be diagnosed exactly by using N-14 antibody as well as by C-100 antibody. In addition for more exact diagnosis of hepatitis C, tests by N-14 antibody in combination with C-100 antibody will be prefered to determine anti HCV.