DETECTION OF SERUM HEPATITIS-C VIRUS-RNA IN HCV ANTIBODY SEROPOSITIVEVOLUNTEER BLOOD-DONORS

Approximately 90% of subjects with chronic hepatitis resulting from he patitis C virus infection have hepatitis C virus RNA in serum. However , the prevalence of hepatitis C virus RNA in serum from subjects with hepatitis C virus antibody associated with persistent normal liver bio chemical values is unclear. Do these subjects have resolved or continu ing infection with hepatitis C virus? The aim of this study was to exa mine whether subjects with hepatitis C virus antibody but normal ALT l evels had evidence of ongoing infection. Our study population was divi ded into four groups. Groups 1, 2 and 3 comprised hepatitis C virus an tibody-positive volunteer blood donors. Group 1 was made up of subject s found to be hepatitis C virus antibody-positive on enzyme-linked imm unosorbent assay with persistent abnormal ALT levels (59 donors: 53 po sitive on recombinant immunoblot assay and 6 indeterminate). Group 2 m embers were hepatitis C virus antibody positive, with persistent norma l ALT levels (50 donors: 39 positive on recombinant immunoblot assay a nd 11 indeterminate). Group 3 members were hepatitis C virus seroposit ive but negative on second-generation recombinant immunoblot assay (n = 48). Twenty patients (not blood donors) with chronic liver disease w ho were anti-hepatitis C virus seronegative were used as controls (gro up 4). Serum samples from all four groups were assayed for hepatitis C virus RNA on reverse transcription and a 40-cycle polymerase chain re action with a combination of primers from the highly conserved 5'-nonc oding and less-conserved third and fourth nonstructural regions. All a ssays were confirmed on hybridization with an internal probe. In group 1, 55 of 59 subjects (93.2%) had hepatitis C virus RNA in serum. In g roup 2, 21 of 50 subjects (42%) had hepatitis C virus RNA in serum. Tw enty-one of the 39 recombinant immunoblot assay-positive subjects (53. 9%) had hepatitis C virus RNA, compared with none of the 11 recombinan t immunoblot assay-indeterminant subjects (p = 0.001 on chi2 assay). I n recombinant immunoblot assay-positive subjects with normal ALT readi ngs less than 1 mo apart, 7 of 8 (87.5%) had RNA in serum, compared wi th 14 of 31 patients (45%) who were followed for at least 1 mo (mean, 6.1 +/- 6.7) (p = 0.03 on chi2 assay). No subject in group 3 or in gro up 4 had hepatitis C virus RNA in serum. In conclusion, approximately 40% to 50% of subjects with hepatitis C virus antibody positivity and persistent normal liver biochemical values have continuing hepatitis C virus infection.