HEPATITIS-C VIRUS-RNA IN FACTOR-VIII CONCENTRATES

Background: Hepatitis C virus (HCV) RNA was measured in commercial factor VIII concentrates, that is, antihemophilic factor (human) (AHF), to allow the retrospective evaluation of the effect of various virus-inactivation procedures. The impact on AHF of recent anti-HCV screening of plasma was also investigated. Study Design and Methods: A total of 183 lots of AHF made by six United States-licensed manufacturers from anti-HCV-unscreened (1976-1991) or screened (1992-1993) plasma were examined. Detection and quantitation of HCV RNA were achieved by reverse transcription and nested polymerase chain reaction at limiting dilution. Anti-HCV in AHF was also measured. Results: Earlier AHF lots subjected to non-virus-inactivated treatment (36 lots), dry heat (11 lots), or heating in n-heptane (4 lots) had relatively high levels of HCV RNA. Most (76%) wet-heated lots prepared before 1992 contained HCV RNA. No HCV RNA was detected in lots purified by immunoaffinity and subsequently heated or solvent/detergent (S/D)-treated. However, trace levels of HCV RNA were detected in S/D-treated lots made by one of four manufacturers before 1992. Since the start of anti-HCV plasma screening in 1992, 38 lots prepared by six manufacturers were negative for HCV RNA. Prevalence of anti-HCV was also associated with earlier concentrates and with S/D-treated lots from that single manufacturer. Conclusion: Anti-HCV screening of plasma by manufacturers in conjunction with current virus-inactivation procedures, wet-heating or S/D treatment (either process with or without affinity purification), appears to reduce HCV RNA to undetectable levels in AHF.