EARLY DETECTION OF ANTI-HCC ANTIBODY IN ACUTE HEPATITIS-C VIRUS (HCV)BY WESTERN-BLOT (IMMUNOBLOT) USING A RECOMBINANT HCV CORE PROTEIN-FRAGMENT

Crude extract from Escherichia coli which expressed a recombinant prot ein containing amino acids 2 to 127 of the hepatitis C virus (HCV) cor e protein was used to detect the antibody against HCV core protein (an ti-HCc). After electrophoretic separation of proteins from the extract , Western blot (immunoblot) analysis was performed with the serum samp les. This method was compared with a commercially available second-gen eration enzyme immunoassay (EIA) which employed synthetic peptides cor responding to highly antigenic segments of both structural and nonstru ctural portions of HCV. Also, reverse transcription PCR for HCV RNA wa s used for comparison. Seventy-two serum samples from three groups of patients were tested. Groups I and II represented healthy subjects and subjects with acute hepatitis A or B, respectively. Group III include d patients with newly acquired acute hepatitis C. By Western blot anal ysis, 31 of 31 (100%) samples from group I were negative for anti-HCc antibody, whereas 4 of 22 (18%) samples from group II were positive fo r anti-HCc. One of these four samples was also positive for anti-HCV a ntibody by the second-generation EIA (1 of 22 [4.5%]). Among 19 patien ts diagnosed with newly acquired acute hepatitis C, 4 (21%) were posit ive for anti-HCV by the second-generation EIA, whereas 12 of 19 (63%) were positive for anti-HCc by Western blot analysis. Of EIA-positive s ubjects, 4 of 4 (100%) were also positive for anti-HCc by Western blot analysis, whereas among EIA-negative subjects, 8 of 15 (53%) were pos itive. For HCV RNA detected by reverse transcription PCR, 15 of 19 (80 %) of this group of samples were positive. Strikingly, the peak biliru bin level for patients with EIA-negative and Western blot-positive res ults is significantly higher than that for patients with consistent EI A and Western blot results (22.7 versus 7.2 mg/dl). A series of serum samples from a patient with concurrent hepatitis B and C viral infecti on was also studied by both tests. Although anti-HCc persisted through out the course of infection, anti-HCV by EIA converted from negative t o positive 20 days after admission and then converted back to negative 30 days later.