GENOTYPING HCV ISOLATES FROM ITALY BY TYPE-SPECIFIC PCR ASSAY IN THE CORE REGION

A revision of the polymerase chain reaction (PCR) core procedure was p erformed for genotyping hepatitis C virus (HCV) in 139 patients from I taly. This procedure, developed prior to the identification of new gen otypes, may be inadequate in several geographical areas. We proposed a new typing mixture in which primers for types 2c and 4, that are repo rted to be circulating in Italy, were added and a primer for type 2b w as substituted. Using the modified procedure, 139 HCV-positive patient s were analysed. The HCV genotype was identified in 96.4% of the cases . We observed double infections and unclassified genotypes in 5 (3.6%) and 5 (3.6%) patients, respectively The classification of isolates in to genotypes and subtypes 2b, 2c and 4 was confirmed by sequence analy sis. Furthermore, the efficiency and accuracy of the modified core pro cedure were evaluated by parallel testing of 107 out of 139 samples us ing the line probe assay, and demonstrated a 98.9% degree of concordan ce. The results demonstrated the specificity of the selected primers f or type 2c, 2b and 4 and confirmed the circulation of types 2c and 4 i n Italy. In conclusion, the proposed modified PCR procedure is the onl y primer-specific PCR genotyping method available for identification o f the 2c and 4 genotypes reported to be circulated in Italy and other European countries.