Serotyping and genotyping of hepatitis C virus in Taiwanese patients with type C chronic liver disease and uraemic patients on maintenance haemodialysis

Background: To evaluate a recombinant immunoblot hepatitis C virus (HCV) se rotyping assay, which determines HCV serotypes 1, 2, and 3 by detecting typ e-specific antibodies to core-and NS-4-derived peptides. Methods: Immunoreactivity of type-specific antibodies among 173 chronic hep atitis C patients and 43 haemodialysis patients in Taiwan was examined and the serotyping results were compared with genotyping by Okamoto's method. S erial specimens from 29 patients undergoing interferon-alpha therapy were a lso evaluated. Results: Of the 205 specimens for which genotyping data were available, 51. 2% were of serotype 1, 31.7% of serotype 2, 1.0% of serotype 3, 2.4% of eit her serotype 1 or 3, and the remaining 13.7% were untypable. The serotypabl e rate was significantly lower in haemodialysis patients than in chronic he patitis C patients (70.0% vs 94.9%; P < 0.001). Serotyping of genotype 2b s pecimens was significantly more dependent on core peptide bands than other genotypes. Using genotyping as the reference, the overall sensitivity, spec ificity and concordance of the recombinant immunoblot HCV serotyping assay were 86.3%, 97.2% and 83.9%, respectively. However, the serotyping assay ha d significantly lower sensitivity (69.2%), specificity (77.8%) and concorda nce (53.8%) for genotype 2b specimens. Of nine HCV complete responders, one lost type-specific antibodies 6 months after the cessation of interferon-a lpha treatment. Conclusions: These results suggest that, except for less than optimal perfo rmance with immunocompromised or genotype 2b patients, the HCV serotyping a ssay is a practical and useful method for HCV typing in the clinical settin g in Taiwan. (C) 2000 Blackwell Science Asia Pty Ltd.