Hepatitis C virus antibodies, viral RNA levels and genotypes in Thailand

Hepatitis C virus is the main causative agent of post-transfusion hepatitis and can cause chronic liver disease, liver cirrhosis and hepatocellular carcinoma. Sequential comparisons between genomes of HCV indicate that HCV can be calssified into genotypes which show significant geographical and epidemiological distributions. We used specific primers for genotyping of HCV in 65 specimens of chronic hepatitis and blood donors. Forty specimens (70.18%) were infected with HCV genotype V/3a, 7 specimens (12.28%) with genotype IV/1b, 5 specimens (8.77%) with genotype II/1b and V/3a, and 5 specimens (8.77%) with unclassified type in a distribution comparable with the chronic hepatitis and blood donors. We also detected the level of HCV-RNA titers by branch DNA probe assay. Our data showed that 30 cases (73.17%) of blood donors had high HCV-RNA titers in contrast to 8 of the 24 (33.33%) patients with chronic hepatitis. The bDNA assay for HCV-RNA titers was less sensitive than the PCR method for HCV-RNA detection. HCV-RNA levels more than 0.35 Meq/ml were found in 66.7% (4/6) of genotype II/1b, 65% (26/40) in type V/3a and 80% (4/5) in type II/ 1b + V/3a. There were no statistical differences among genotypes. The assay of HCV-RNA genotypes and quantification of HCV-RNA level provide more accurate assessment and therapeutic monitoring and facilitate in deciding the optimum dose and duration of interferon treatment.