Hepatitis C viral RNA in clotting factor concentrates and the development of hepatitis in recipients

The polymerase chain reaction (PCR) was used to detect hepatitis C (HCV) viral sequences (HCV-RNA) in clotting factor concentrates that had been stored at 4 degrees C for 1 to 16 years. A total of 43 concentrates were tested, comprising 31 batches of factor VIII, 6 of factor IX, 2 of antithrombin III, 3 of FEIBA, and 1 of factor VII. HCV-RNA was detected in 13 of the 43 batches (30.2%). Concentrates that had not undergone viral inactivation during manufacture were significantly more likely to contain detectable HCV-RNA than concentrates that had been virally inactivated (56.3% v 14.5%, P = .006). HCV sequences were more commonly detected in concentrates made from paid donor plasma than in those made from volunteer donor plasma (44% v 11%, P = .041), and more commonly in virally inactivated concentrates with pre-1989 than with post-1989 expiration dates (50% v 0%, P = .004). Of the four batches of heat-treated products that were HCV-RNA positive, at least three transmitted non-A, non-B hepatitis (NANBH). An association between the presence of HCV-RNA in concentrates and the development of NANBH was demonstrated in nine previously untreated patients on prospective follow-up. HCV-RNA was detected in the concentrates administered to the six patients whose alanine aminotransferase (ALT) abnormalities met the diagnostic criteria for NANBH and who later seroconverted for HCV, but it was not detected in the concentrates administered to the three patients whose ALT abnormalities failed to satisfy the diagnostic criteria and who did not seroconvert. We suggest that the use of this PCR technique to monitor clotting factor concentrates derived from pooled blood may potentially contribute to product safety.