Sakugawa Hiroshi, Nakasone Hiroki, Nakayoshi Tomofumi, Orito Etsuro, Mizokami Masashi, Yamashiro Tsuyoshi, Maeshiro Tatsuji, Kinjo Fukunori, Saito Atsushi, Miyagi Yasuhiro
First Department of Internal Medicine, University Hospital, Faculty of Medicine, University of the Ryukyus, Uehara, Okinawa, Japan.
J Med Virol. 2002 Aug;67(4):484-9. doi: 10.1002/jmv.10127.
The present study was designed to examine the distribution of hepatitis B virus (HBV) genotypes among patients at various stages of chronic liver disease type B in Okinawa Prefecture, Japan, where the prevalence of hepatitis B surface antigen is the highest in Japan despite the lowest mortality rate from primary liver cancer. Serum samples from 227 HBV carriers were determined for HBV genotype by polymerase chain reaction (PCR)-restriction fragment length polymorphism. Five of 227 sera were negative for HBV DNA by nested PCR and were excluded from the genotype analysis. Genotype B was predominant in asymptomatic carriers (45/67, 67%), whereas genotype C was predominant in chronic liver disease: 49% (50/103) in patients with chronic hepatitis, 63% (20/32) in patients with cirrhosis, and 60% (12/20) in patients with hepatocellular carcinoma. The distribution of genotype B decreased with increasing liver disease severity. However, this tendency was seen among patients aged less than 50 years old, whereas the prevalence of genotype B was similar among carriers with various liver diseases who were older than age 50. In conclusion, HBV genotype B was prevalent and less frequent among patients with advanced liver disease, particularly in patients aged less than 50 years. These findings suggest that the preponderance of genotype B is responsible for the low mortality rate of primary liver cancer associated with HBV seen in Okinawa Prefecture, despite having the highest HBV carrier rate in Japanese.
本研究旨在调查日本冲绳县B型慢性肝病各阶段患者中乙型肝炎病毒（HBV）基因型的分布情况。冲绳县的乙型肝炎表面抗原流行率在日本最高，但其原发性肝癌死亡率却是日本最低。采用聚合酶链反应（PCR）-限制性片段长度多态性方法，对227例HBV携带者的血清样本进行HBV基因型检测。227份血清样本中有5份经巢式PCR检测HBV DNA呈阴性，被排除在基因型分析之外。B基因型在无症状携带者中占主导地位（45/67，67%），而C基因型在慢性肝病患者中占主导地位：慢性肝炎患者中占49%（50/103），肝硬化患者中占63%（20/32），肝细胞癌患者中占60%（12/20）。B基因型的分布随着肝病严重程度的增加而减少。然而，这种趋势在年龄小于50岁的患者中较为明显，而在年龄大于50岁的不同肝病携带者中，B基因型的流行率相似。总之，B基因型HBV在晚期肝病患者中较为普遍，但频率较低，尤其是在年龄小于50岁的患者中。这些研究结果表明，尽管冲绳县HBV携带率在日本最高，但B基因型占优势是冲绳县HBV相关原发性肝癌死亡率较低的原因。
