COMPARATIVE-STUDY OF 3 METHODS FOR GENOTYPING HEPATITIS-C VIRUS-STRAINS IN SAMPLES FROM SPANISH PATIENTS

Hepatitis C virus (HCV) genotypes may be investigated by a variety of laboratory methods that target different parts of the HCV genome and h ave various degrees of technical difficulty, Since the choice of a par ticular method is difficult, we compared the performance of (i) a type -specific PCR with type-specific primers from the core region, (ii) mo lecular hybridization of the PCR-amplified 5' noncoding region to type -specific probes, and (iii) identification of type-specific antibodies against epitopes of nonstructural region 4 by enzyme-linked immunosor bent assay (ELISA), One hundred fifty-one patients with biopsy-proved chronic hepatitis and HCV RNA in serum were investigated, The HCV geno type was identified in 99%, 100%, and 85% of the cases by type-specifi c PCR, probe hybridization, and ELISA, respectively. The type-specific PCR disclosed infection with type la in 3%, type Pb in 74%, and type 3a in 4% of the cases and suggested infection with two or more HCV typ es, including 2a/2c and 2b, in the remaining 18%. Apparently mixed inf ections were more prevalent in patients with past intravenous drug use (P < 0.001), but cloning and sequencing of PCR products did not confi rm a mixed infection in any of the four cases investigated, Concordant results were obtained by the three procedures with virtually all of t he samples in which the type-specific PCR revealed a single HCV genoty pe, Type-specific hy hybridization and ELISA usually recognized the ge notype producing the strongest DNA band in samples in which type-speci fic PCR suggested a mixed infection, In conclusion, the three procedur es evaluated in this study are reliable for investigation of HCV genot ypes, Type-specific PCR provides information about HCV subtypes, but a mixed infection detected with this method should be interpreted with caution.