Because of its practicability, the HC02 assay is a very useful alternative to molecular methods of HCV type determination (7)

Because of its practicability, the HC02 assay is a very useful alternative to molecular methods of HCV type determination (7). viral enzymes. Nucleotide sequence analyses from numerous HCV genomes have indicated that this envelope (and genes are highly variable, in contrast to the UTRs, which are highly conserved (14). Phylogenetic analysis of nucleotide sequences Morin hydrate of numerous isolates has enabled definition of six clades and many subtypes within them (4, 5, 17, 18, 20, 21). Type and subtype classification of HCV strains Morin hydrate has enabled specific description of the geographic distribution of the viral types (examined in reference 23): Morin hydrate HCV types 1, 2, and 3 have a worldwide distribution, while the other types are found mainly in North and Central Africa (type 4), South Africa (type 5), and Southeast Asia (type 6) (18, 19). However, local patterns might also occur. For example, phylogenetic analyses of the gene have recently indicated the emergence of HCV type 4 in the northeastern suburbs of Paris (France) (13). In addition to the epidemiological relevance, viral typing might have a clinical impact. Numerous studies have reported a relationship between HCV type and the response to interferon or pegylated interferon therapy, given alone or in combination with Ribavirin (12). Patients infected with HCV type 2 or 3 3 have a better response to treatment than those infected with HCV type 1. Consequently, the recommended period of 6 months of therapy for HCV type 2 or 3 3 infections is usually extended to 1 1 year for HCV type 1 infections (9, 12). Therefore, HCV type determination is now routinely performed when therapy is usually indicated. Many molecular methods based on reverse transcription and PCR amplification of various regions of the viral RNA have been developed to assess HCV genotypes (4, 8, 15, 19-21). Genotyping methods are usually highly sensitive and specific but are expensive, require proper handling and storage of the samples, and can be Rabbit Polyclonal to Dyskerin performed only on HCV RNA-positive samples. Genotype-specific synthetic peptides derived from the NS4 amino acid sequence have been used in an enzyme-linked immunosorbent assay (ELISA) to detect the presence of type-specific antibodies in the sera of infected patients (1, 18). Such a serological typing approach for typing HCV is easy to perform and remains reliable even when HCV RNA is usually undetectable. The HCV Serotyping 1-6 assay (HC02; Abbott Murex) is currently used because it has a high specificity (97.6%) compared to genotyping results (7, 10). The sensitivity of the test ranges from 70 to 87% but can be lower for samples from patients either coinfected with human immunodeficiency computer virus (HIV) (and thus immunosuppressed) or with mixed cryoglobulinemia (10) (our unpublished results). Using a collection of HCV RNA-positive samples for which the HC02 serotyping assay experienced failed to determine the computer virus type, we evaluated a new version of the test (HC03). From this panel, 37.6% of the samples not typeable with HC02 were typed using HC03. MATERIALS AND METHODS Samples. A total of 180 HCV-RNA positive samples (HCV Monitor 1.0; Roche Diagnostics) which experienced previously been tested in a pretherapeutic setting by using the current Abbott Murex HCV Serotyping 1-6 assay (HC02) version were selected and retrospectively analyzed with the new version of Morin hydrate the test (HC03). Of these 180 samples, 39 sera previously serotyped with HC02 were used as controls. The six HCV types were represented and distributed as follows: type 1, = 5; type 2, = 5; type 3, = 7; type 4, = 6; type 5, = 8; type 6, = 4; and mixed types, = 4 (types 1 plus 4, 4 plus 5, 3 plus 6, and 2 plus 6). The remaining 141 samples, which HC02 experienced failed to type, were tested with HC03 to assess the improvement of sensitivity of HC03 over HC02. Of these samples, 42 were positive for HIV antibodies, 44 were negative, and the HIV serological status was not known for 55. Another panel of 22 HCV RNA-positive samples, Morin hydrate which belonged to a multicenter quality control panel (ANRS; Action Concerte 11), were genotyped using INNO-LiPA HCV II (Innogenetics), which allows typing and subtyping (although subtype determination is not usually accurate with this test), and the results were compared to those generated from serological typing using both HC02 and HC03. HCV serological typing. The HCV Serotyping 1-6 assay is an ELISA which distinguishes type-specific antibodies to the six major HCV types. Both HC02 and HC03 make use of a 96-well microtiter plate as the solid phase, with wells coated with synthetic HCV NS4 peptides of each type. Type-specific antibodies present in the.