ANALYSIS OF HEPATITIS C VIRUS SUBTYPES AND ITS CLINICAL SIGNIFICANCE.

探讨丙型肝炎病毒（HCV）亚型的临床意义。用型特异性cDNA探针在NS 5区进行印迹，确定了HCV的7种亚型（1a，1b，2a，2b，3a，3b，4a）。在来自世界各地的约1,600份样本中，未发现HCV-3b，偶尔主要在非洲样本中检测到HCV-4a。表明这两种类型仅在有限的区域内分布，其余5种类型在世界范围内普遍分布。为获得准确的HCV亚型分型结果，需要多种分型方法的联合分析。在日本的一项全国性分析中，证实了干扰素（IFN）治疗HCV 1b相关患者的效果明显优于非相关患者。在西方国家，IFN治疗HCV-3a患者的效果往往优于HCV-1b患者。IFN治疗期间HCV滴度的变化可分为3种类型：快速下降（A）型、高滴度（B）型、高滴度（C）型和高滴度（D）型。 ...更多信息 持续型（C）和介于A型和C型之间的中间型（B）。HCV亚型间IFN效应的差异可能是由于HCV亚型的性质不同，而不是HCV-RNA的含量不同。应用单链构象多态性分析方法，对HCV IFN敏感性决定区的定量人群进行了分析。在C型中，以IFN抗性型的准种最多。而A型则以IFN敏感型多见。HCV-1b在世界不同国家的流行率与肝细胞癌（HCC）的发病率显著相关。在日本，不同都道府县的HCV-1b流行率与HCC死亡率之间存在显著相关性，HCC患者中HCV-1b的流行率显著高于非HCC患者，HCV-1b的HCC发展时间较其他亚型的HCV短，提示HCV-1b的致癌性可能较其它亚型强。少

Clinical significance of the subtypes of hepatitis C virus (HCV) was studied. Seven (1a, 1b, 2a, 2b, 3a, 3b, 4a) subtypes of HCV were determined by blotting using type specific cDNA probes at the NS5 region. In about 1,600 samples obtained from the world, HCV-3b was not found, and HCV-4a was detected occasionally mainly in samples from Africa. indicating these two types distributed in only limited area, and the other 5 types commonly distributed through the world. To obtain the accurate results of HCV subtypes, a combined analysis with different methods for typing was needed. In a nationwide analysis in Japan, it was confirmed that the effects of interferon (IFN) treatment were significantly better in HCV 1b-related patients than in non-related patients. In the Western countries, the effect of IFN treatment tended to be better in patients with HCV-3a than HCV-1b. The pattern of changes in HCV titers during IFN treatment was classified into 3 types : rapid decreased (A) type, high titer … More sustained (C) type and intermediate (B) type between A and C types. The pattern of C type was found only in patients with HCV-1b and not with HCV-2a and-2b, suggesting that the difference of IFN effects between HCV subtypes may be attributed to the difference of quality of HCV subtypes and not to the quantities of HCV-RNA.Quansispesies population of HCV at the IFN sensitivity determining region were analyzed using single strand conformation polymorphism. In C type, the most quasispesies were IFN-resistance type. On the other hand, the most quasispesies in A type were IFN sensitive type. The prevalence of HCV-1b in different countries of the world was significantly correlated with the incidence of hepatocellular carcinoma (HCC). In Japan, a significant correlation between the prevalence of HCV-1b and mortality rate by HCC in different prefectures was found. The prevalence of HCV-1b in patients HCC was significantly higher than patients without HCC.The duration for the development of HCC was shorted in HCV-1b than the other subtypes of HCV., These results suggest that the oncogenecity of HCV-1b may be stronger than the other subtypes of HCV. Less