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Typing hepatitis C virus by polymerase chain reaction with type-specific primers: application to clinical surveys and
H Okamoto1, Y Sugiyama, S Okada
1Immunology Division, Jichi Medical School, Tochigi-Ken, Japan.
Insights
Hepatitis C virus (HCV) typing identified four distinct types based on core gene variations. Type II was most prevalent in blood donors and non-A, non-B liver disease patients in Japan.
Area of Science:
- Virology
- Molecular Biology
- Hepatology
Background:
- Hepatitis C virus (HCV) is a major cause of chronic liver disease.
- Genotypic variation within HCV complicates diagnosis and treatment.
- Previous studies suggested heterogeneity among HCV isolates.
Purpose of the Study:
- To develop and validate a method for typing Hepatitis C virus (HCV) based on core gene sequences.
- To investigate the distribution of different HCV types in various populations.
Main Methods:
- Nucleotide sequencing of the HCV core gene from 44 isolates.
- Development of a polymerase chain reaction (PCR) assay using universal and type-specific primers for HCV typing.
- Analysis of PCR product sizes to determine HCV types (I, II, III, IV).
Main Results:
- Four distinct HCV types were identified based on core gene sequence variations.
- Type II was the predominant HCV type (82%) in Japanese blood donors and (60%) in patients with non-A, non-B liver disease.
- HCV typing revealed co-infections in patients and haemophiliacs, and identical types in mother-infant pairs and accidental transmission cases.
Conclusions:
- A reliable PCR-based method for HCV typing was established.
- HCV type distribution varies between different risk groups and geographical locations.
- Understanding HCV genotypes is crucial for tracking transmission and managing liver disease.
Abstract:
Based on variation in nucleotide sequence within restricted regions in the putative C (core) gene of hepatitis C virus (HCV), four groups of HCV have been postulated in a panel of 44 HCV isolates. They were provisionally designated types I, II, III and IV. A method for typing HCV was developed, depending on the amplification of a C gene sequence by polymerase chain reaction using a universal primer (sense) and a mixture of four type-specific primers (antisense). HCV types were determined by the size of the products specific to each of them. Type II was found in HCV samples from 131 (82%) of 159 blood donors, more often than in those from 48 (60%) of 80 patients with non-A, non-B (NANB) liver disease in Japan (P less than 0.01). In 11 haemophiliacs who had received imported coagulation factor concentrates, type I was found in five, as against type II in four. Double infection with two different HCV types was found in two patients with chronic NANB liver disease (types I and II; II and III) and two haemophiliacs (types I and II; I and III). HCV types were identical in mother and baby in each of two examples of perinatal transmission, and were also identical in donor and recipient in a case of accidental needle exposure.