Assay of HCV‐related antibodies and their consequent changes following interferon treatment

The hepatitis C virus (HCV) core antibody and NS‐4 antibody were measured in 25 cases of type C chronic hepatitis after interferon (IFN) treatment. The antibody titres were quantitated and the changes in the antibody titres and the therapeutic effects were compared. The titres of the passive haemagglutination assay (HCV‐PHA) before and after IFN administration were also measured and compared with the therapeutic effects. No significant correlation was seen between the core, NS‐4 and HCV‐PHA titres before IFN administration and the resultant therapeutic effects, but many cases showing excellent effects were seen among those with core antibody titres under 100 U/L and those with HCV‐PHA titres less than 2.¹⁶ In a study of the changes in the core and NS‐4 antibody titres, these titres tended to decrease during IFN administration. In cases showing excellent effects, these decreases continued for a long period after completion of IFN administration and then became negative in some cases. However, in the remaining cases, titres showed increases up to 3 months after completion of IFN administration. HCV‐PHA showed reduced titres in many cases of excellent effects before and after IFN administration; and there were also cases showing decreases with two power differences.