Smith D B, Davidson F, Simmonds P
Department of Medical Microbiology, University of Edinburgh Medical School, Scotland, UK.
J Hepatol. 1995;23 Suppl 2:26-31.
Hepatitis C virus demonstrates considerable divergence in nucleotide sequence. This variation may affect virus detection, disease outcome, and the effectiveness of interferon treatment. For example, infection with genotype 1 is associated with a lower response rate to interferon treatment. Hepatitis C virus can be classified into six distinct types, comprising at least 74 different subtypes. Both types and subtypes are subject to geographical differences in distribution, presumably reflecting the epidemiological history of the virus. However, because this history may be blurred by migration and by commerce in blood products between regions, screening and typing assays must recognize both the major indigenous and more exotic virus genotypes. Little information exists about the role of virus sequence variation in screening for hepatitis C virus antibodies, but there is some evidence that the reactivity of current serological screening assays for hepatitis C virus is genotype dependent. In the future, screening assays may need to include antigens specific for different virus types or may need to be designed with regard to the particular types found in a certain area. Antigenic variation may also mean that an effective vaccine needs to be multivalent to protect against all genotypes present in a given region. There are several polymerase chain reaction-based methods of distinguishing between hepatitis C virus variants. These methods must be continually updated, however, as new sequence variants are discovered. Alternative genotyping assays are based on the host's serological response to virus infection, but these cannot distinguish between virus subtypes and are unsuitable for immunocompromised patients. As more countries are sampled, it is likely that more genotypes will be identified and this may help elucidate the origins of hepatitis C virus. Detailed epidemiological studies may delineate past and current routes of transmission.
丙型肝炎病毒在核苷酸序列上表现出相当大的差异。这种变异可能会影响病毒检测、疾病转归以及干扰素治疗的效果。例如，感染1型基因型与对干扰素治疗的较低反应率相关。丙型肝炎病毒可分为六种不同类型，包括至少74种不同的亚型。病毒类型和亚型在地理分布上存在差异，这大概反映了该病毒的流行病学历史。然而，由于这种历史可能因地区间的人口迁移和血液制品贸易而变得模糊，筛查和分型检测必须识别主要的本土病毒基因型以及更多外来的病毒基因型。关于病毒序列变异在丙型肝炎病毒抗体筛查中的作用，目前所知甚少，但有一些证据表明，当前丙型肝炎病毒血清学筛查检测的反应性取决于基因型。未来，筛查检测可能需要包含针对不同病毒类型的特异性抗原，或者可能需要根据特定地区发现的特定病毒类型来设计。抗原变异也可能意味着有效的疫苗需要是多价的，以预防给定地区存在的所有基因型。有几种基于聚合酶链反应的方法可用于区分丙型肝炎病毒变异体。然而，随着新的序列变异体被发现，这些方法必须不断更新。替代的基因分型检测基于宿主对病毒感染的血清学反应，但这些方法无法区分病毒亚型，且不适用于免疫功能低下的患者。随着更多国家被纳入样本，可能会发现更多的基因型，这可能有助于阐明丙型肝炎病毒的起源。详细的流行病学研究可能会描绘过去和当前的传播途径。
