Typing hepatitis C virus by polymerase chain reaction with type-specific primers: application to clinical surveys and tracing infectious sources

1 Immunology Division, Jichi Medical School, Tochigi-Ken 329-04, 2 Department of Hygiene, University of Hiroshima, Hiroshima-Ken 734, 3 First Department of Internal Medicine, Yamanashi Medical College, Yamanashi-Ken 409-38, 4 Department of Internal Medicine, Iwaki Kyoritsu General Hospital, Fukushima-Ken 973, 5 Japanese Red Cross Blood Center, Saitama-Ken 362, 6 Department of Immunology, The Kitasato Institute, Tokyo 108 and 7 Mita Institute, Tokyo 108, Japan 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 < 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. Received 9 September 1991; accepted 7 November 1991.