Analysis of the mechanism of liver injury and carcinogenesis in HCV infection

自从从实验感染的黑猩猩血浆中克隆出丙型肝炎病毒的基因组以来，对丙型肝炎病毒抗体的检测表明，丙型肝炎病毒是大多数非甲非乙型肝炎的病原体。我们评估了抗丙型肝炎病毒核心蛋白抗体的流行情况，发现95%以上的NANB慢性肝病与丙型肝炎病毒有关，抗丙型肝炎病毒核心蛋白的存在与丙型肝炎病毒携带者密切相关。我们通过竞争性RT-PCR法对血清中的丙型肝炎病毒RNA进行定量，以将丙型肝炎病毒的复制水平与(1)携带者状态的不同阶段或(2)对干扰素(IFN)治疗的持续应答相关联。血清中的丙型肝炎病毒核糖核酸含量在10.4~10.5拷贝/毫升血清之间。无症状献血员和慢性迁延性肝炎患者的HCVRNA滴度均低于慢性活动性肝炎、肝硬变和肝细胞癌患者。初始滴度…长期应答者干扰素治疗前HCVRNA水平明显低于短期应答者和无应答者。多变量分析显示，治疗前的丙型肝炎病毒RNA滴度是干扰素治疗持续应答的最强独立预测因子。我们通过免疫组织化学研究和原位杂交技术确定了感染丙型肝炎病毒的肝细胞的定位。在所研究的标本中，只有不到50%的标本呈阳性染色或信号。阳性的肝细胞散在分布于小叶内。小叶内炎症和纤维化在阳性结果的样本中得分高于阴性样本。在肝细胞癌患者的肝组织中，用聚合酶链式反应检测到链特异性的丙型肝炎病毒核糖核酸，发现癌组织和非癌肝组织中不仅有正链扩增，也有负链扩增。这些结果表明，晚期肝病患者的丙型肝炎病毒复制水平较高，病毒复制水平的升高可能在肝损伤、肝病进展和癌变过程中起重要作用。较少

Since the genome of hepatitis C virus (HCV) was been cloned from experimentally infected chimpanzee plasma, testing for antibody to hepatitis C virus has shown that HCV is the etiological agent for most cases of non-A, non-B (NANB) hepatitis. We evaluated the prevalence of antibody to the core protein of HCV and found that HCV is related with more than 95% of NANB chronic liver disease and that there is a close correlation between the presence of anti-HCV core and HCV carriers. We quantified HCV RNA in serum by the competitive RT-PCR assay to correlate the replicative level of HCV with (1)various stages of the carrier states or (2)a sustained response to interferon (IFN) therapy. The amounts of HCV RNA in serum ranged from 10^4 to 10^<9.5> copies/mL serum. The titer of HCV RNA were lower in asymptomatic blood donors and in patients with chronic persistent hepatitis compared with those having chronic active hepatitis, liver cirrhosis and hepatocellular carcinoma (HCC). The initial titer … More of HCV RNA before IFN therapy of long-term responders were significantly lower than those of short-term responders and non-responders. Multivariate analysis showed that the HCV RNA titer before therapy was the strongest independent predictor of a sustained response to IFN therapy. We determined the localization of the HCV-infected hepatocytes by immunohistochemical studies and "in situ"hybridization technique. Positive staining or signal was found in less than 50% of studied specimens. Hepatocytes with positive results were scattered in the lobules. Intralobular inflammation and fibrosis had higher scores for samples with positive rather than negative results. In liver tissue of patients with HCC, detection of strand-specific HCV RNA by PCR showed that not only positive-strand but also negative-strand could be amplified in both cancerous and non- cancerous liver tissue. These results showed that the replicative level of HCV is higher in advanced liver disease, and that elevation of viral replication might play an important role in liver injury, progression of liver disease and carcinogenesis. Less