MARKERS OF HEPATITIS-C VIRUS-INFECTION IN SARDINIAN BLOOD-DONORS - RELATIONSHIP WITH ALANINE AMINOTRANSFERASE LEVELS

Serum samples from 1,765 consecutive Sardinian blood donors, negative for hepatitis B surface antigen (HBsAg) and for antibodies to human im munodeficiency virus (HIV) (anti-HIV), were evaluated for the presence of antibodies to hepatitis C virus (anti-HCV) by second-generation EL ISA. Anti-HCV was detected in 25 (1.45%) of the 1,765 donors examined. Anti-HCV was found in 15 of the 1,690 (0.9%) donors with normal alani ne aminotransferase (ALT) and in 10 of the 75 (13%) donors with elevat ed ALT (P < 0.0001). Of the 15 anti-HCV-positive donors with normal AL T, only five (33%) were confirmed to be positive by second-generation RIBA, six (40%) were indeterminate, while four (27%) were RIBA negativ e. HCV RNA, as detected by polymerase chain reaction (PCR) using a set of primers from the 5'-noncoding region, was found in six of the 15 ( 40%) donors with normal ALT, including five RIBA positive and one inde terminant. Of the 10 anti-HCV-positive donors with elevated ALT, all w ere RIBA positive and eight (80%) had detectable HCV RNA, Thus, among ELISA-reactive donors, those with elevated ALT had a significantly hig her probability of being positive for second-generation RIBA and HCV R NA compared to those with normal ALT levels (P = 0.028). None of the 6 5 donors with elevated ALT but negative for anti-HCV by ELISA had dete ctable serum HCV RNA, as compared to eight of 10 anti-HCV ELISA-positi ve donors (P < 0.0001). However, although negative for HBsAg, 12 of th e 65 (18%) had serum HBV DNA by PCR. This study demonstrates that the combined use of second-generation ELISA and RIBA anti-HCV assays is hi ghly effective in identifying HCV infection, whereas the specificity o f ELISA alone for the screening of blood donors with normal ALT values appears to be limited. In contrast, in donors with elevated ALT level s, there is a positive correlation between second-generation assays (E LISA and RIBA) and HCV viremia. The high proportion of inapparent HBV infection in blood donors with elevated ALT levels underlines the impo rtance of this test for the prevention of transfusion-associated viral hepatitis. (C) 1993 Wiley-Liss, Inc.