Hepatitis "C" antigen in non-A, non-B post-transfusion hepatitis.

Evidence for a new hepatitis-specific antigen has been obtained from double immunodiffusion assays between acute and convalescent sera obtained from patients with non-A, non-B post-transfusion hepatitis. The designation hepatitis C (HC) antigen is proposed. HC was found in the acute-phase sera of all 13 non-A, non-B post-transfusion hepatitis patients with longer incubation and duration periods (type 2) tested, but only transiently in 4 out of 10 acutephase sera obtained from patients with type 1 non-A, non-B hepatitis, with shorter incubation and duration periods. The antigen was also detected in 2 out of 16 single specimens obtained during the acute phase from acute hepatitis patients who had not received a blood-transfusion. This suggests presence of a carrier state. No patients with alcoholic hepatitis and no healthy blood-donor carried HC antigen. The antigen seems distinct from those of hepatitis A and B (surface and core). It migrated in the serum beta-globulin region and had a buoyant density of 1.30 and a molecular weight between 100 000 and 300 000. Antibodies against HC antigen were found in only 30% of the type-2 non-A, non-B post-transfusion hepatitis patients and did not persist for long. However, these antibodies were directed specifically against HC antigen and moved in a manner similar to 7S globulin on rate-zonal centrifugation.