Antibody to hepatitis-C-virus-related proteins in sera from alanine-aminotransferase-screened blood donors and prospectively studied recipients.

A prospective study of posttransfusion non-A, non-B hepatitis was conducted in Malmö, Sweden, in 1984-1985, in which donors were alanine aminotransferase (ALT) screened but not ALT selected. Among 741 patients studied at 0, 6, and 12 weeks after transfusion, 13 developed non-A, non-B hepatitis, and these were further followed up. Stored sera from the 13 hepatitis patients and their 123 donors were tested for anti-hepatitis C virus (HCV) by ELISA and if positive, analyzed by recombinant immunoblot assay (RIBA). All ALT-elevated blood units (n = 301) and a similar number of ALT-normal units were also tested. Only 4/13 patients with non-A, non-B hepatitis seroconverted to anti-HCV, all with ALT peaks greater than 10 times the upper normal. All seroconversions occurred within 5 months after transfusion and could be confirmed by RIBA. Hepatitis C in recipients occurred both after transfusion of blood that was strongly positive, weakly positive, and/or negative for anti-HCV by ELISA. In donors grouped by ALT levels, the anti-HCV prevalence varied between 0.4 (normal ALT) and 14% (ALT elevated greater than or equal to 2 times). Of the total of 9 donor units positive by ELISA, only 5 were confirmed by RIBA. Of the 5 recipients of the RIBA-positive blood units, 3 went into hepatitis, 1 remained normal at 10.5 weeks, and 1 showed a slight, transient ALT elevation at week 12. The recipients of ELISA-positive but RIBA-negative blood remained healthy.