Non-A, non-B posttransfusion hepatitis: comparing C and non-C hepatitis.

Using assays to detect antibodies against antigens (C-100, 5-1-1, C-22 and C-33) of the hepatitis C virus, we tested stored sera from 40 patients prospectively identified as having non-A, non-B posttransfusion hepatitis. The 28 patients who demonstrated seroconversion ("documented hepatitis C") had more severe initial disease; all 20 cases of chronic hepatitis occurred in this subgroup. Only 2 of the 12 patients who did not demonstrate such seroconversion even had symptoms. In the group of patients with documented hepatitis C, chronic hepatitis was more commonly seen in men (89%) than in women (40%). The patients in whom antibody to the C-100 antigen developed were younger and had received more blood than had those patients who had hepatitis C diagnosed by demonstration of antibodies to the 5-1-1, C-22 or C-33 antigen (or all three). The proportion of cases of posttransfusion hepatitis that could be associated with antibody sero-conversion decreased around the time that blood banks switched to an all-volunteer system. The hepatitis seen in patients who failed to demonstrate serological evidence of hepatitis C virus exposure was usually clinically unimportant; it may or may not have been due to viral infection.