对慢性感染患者丙型肝炎病毒核心编码序列的分析揭示了古巴基因型 1b 分离株的变异性、优势、遗传史和对治疗的潜在影响。

Analysis of hepatitis C virus core encoding sequences in chronically infected patients reveals mutability, predominance, genetic history and potential impact on therapy of Cuban genotype 1b isolates.

机构信息

Centro de Ingeniería Genética y Biotecnología, Havana, Cuba.

出版信息

Eur Rev Med Pharmacol Sci. 2011 Nov;15(11):1320-7.

PMID:22195367

Abstract

BACKGROUND AND OBJECTIVES

Hepatitis C virus (HCV) genotypes are relevant to epidemiological questions, vaccine development, and clinical management of chronic HCV infection. In the present work, we aimed at investigating HCV genotype, variability and genetic history of HCV isolates in Cuba from a sample of chronically infected patients.

MATERIAL AND METHODS

A prospective study, involving 73 Cuban anti-HCV positive patients, was carried out. RT-PCR and phylogenetic analysis was employed to determine HCV genotypes. Divergence dates and demographic parameters in a Bayesian coalescent framework were estimated, as implemented in BEAST v1.4.8.

RESULTS

HCV RNA was undetectable in 15 patients that received antiviral therapy. All HCV RNA positive patients, 58, were infected with genotype 1, three of them with subtype 1a and 55 with subtype 1b. The analysis of the DNA sequence coding for a core fragment, spanning nt positions 435-816 (relative to strain H77), revealed high percent (96.7% +/- 0.8%) nucleotide identity within Cuban HCV subtype 1b sequences. However, 56.7% and 20% of 30 analyzed individuals had changes in the core region in a six-month interval, at the nucleotide and amino acid level, respectively. Mutations involving aa changes were mainly found in the region encompassed between aa 70 and 106 of the core protein, with only one isolate showing a point mutation at position 43. Interestingly, some of the observed changes seem to be reversions and might in fact contribute to reducing the variability of this region. The estimated date for the most recent common ancestor of HCV genotype 1b Cuban isolates is 1969 (CI, 1953 to 1977).

DISCUSSION

Analysis of HCV core encoding sequences from chronic patients reveals mutability of genotype 1b isolates in Cuba, which seem to be predominant and rapidly multiplied during the eighty decade of last century, and might limit the benefits obtained from current antiviral therapy.

摘要

背景与目的

丙型肝炎病毒（HCV）基因型与流行病学问题、疫苗开发以及慢性 HCV 感染的临床管理有关。本研究旨在调查古巴慢性 HCV 感染患者样本中 HCV 基因型、变异性和遗传史。

材料与方法

进行了一项前瞻性研究，涉及 73 名古巴抗 HCV 阳性患者。采用 RT-PCR 和系统进化分析来确定 HCV 基因型。在贝叶斯合并框架中，使用 BEAST v1.4.8 估计分歧日期和人口统计学参数。

结果

接受抗病毒治疗的 15 名患者 HCV RNA 不可检测。所有 HCV RNA 阳性患者（58 名）均感染了基因型 1，其中 3 名感染了 1a 亚型，55 名感染了 1b 亚型。对编码核心片段（nt 位置 435-816，相对于 H77 株）的 DNA 序列进行分析显示，古巴 1b 亚型 HCV 序列的核苷酸同一性高达 96.7%±0.8%。然而，在 6 个月的时间间隔内，30 名分析对象中有 56.7%和 20%的个体在核苷酸和氨基酸水平上发生了核心区的变化。核心蛋白 aa 变化区的 aa 变化主要发生在 70-106 位 aa 之间，只有一个分离株在 43 位出现点突变。有趣的是，一些观察到的变化似乎是回复突变，实际上可能有助于减少该区域的变异性。HCV 1b 古巴分离株的最近共同祖先估计日期为 1969 年（置信区间，1953 年至 1977 年）。