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目的初步探讨东北部延边地区 HCV 基因型分布和1a 型的感染状况。方法对44例来自延边地区的 HCV RNA 阳性样本进行 HCV5′非编码区(5′NCR)复合酶切分型分析。将分型结果为1a 型的4例样品(分别为 Y2、Y4、Y6、Y8)进行5′NCR 和 NS5B 区的扩增,测序,然后与27个HCV 全基因参考序列(均来自 GenBank)比对并构建遗传进化树。结果 44例样品中1a/1b 混合型19例(43.1%),1b 型12例(27.3%),2a/1b 混合型8例(18.2%),1a 型4例(9.1%),2a 型1例(2.3%),2b 型以及3～6型未检出。其中,1a 型的4例样品 Y2、Y4、Y6、Y8分别与各基因型的全基因参考序列相比较,在5′NCR 与1a 型参考序列 HC-J1的同源性最高,分别为0.990、0.990、0.990、0.990,进化树分析也证实为1a 型;在 NS5B 区与1b 型参考序列 HC-J4的同源性最高,分别为0.936、0.957、0.936、0.936,进化树分析表明为1b 型。结论延边地区以1a/1b 型混合感染为主,1b 型和1b/2a 型感染次之,与中国其他地区存在明显差异。对4例1a 型 HCV 病毒株的分析发现,存在 HCV5′NCR 与 NS5B 分型结果不一致现象。分析推测可能是 HCV 基因组在生物进化过程中自然重组的表现,但尚需进一步研究证实。
Objective To investigate the distribution of HCV genotype and the infection status of type 1a in Yanbian area of northeast China. Methods Forty-four HCV RNA positive samples from Yanbian area were genotyped by restriction endonuclease digestion (5’NCR). The 4 samples (type Y2, Y4, Y6, Y8) of type 1a were amplified, sequenced and then compared with 27 HCV genome reference sequences Pair and construct a phylogenetic tree. Results Of the 44 samples, 19 (43.1%) were classified as 1a / 1b, 12 (27.3%) as type 1b, 8 (2a) Cases (2.3%), 2b and 3 to 6 were not detected. Among them, 1a sample of 4 samples Y2, Y4, Y6, Y8 respectively compared with the whole genome reference sequence of each genotype, in 5’NCR and 1a reference sequence HC-J1 the highest homology, respectively 0.990, 0.990, 0.990 and 0.990 respectively. The phylogenetic tree also showed la type 1a. The NS5B region shared the highest homology with the HC-J4 reference genotype 1b (0.936,0.957,0.936,0.936, respectively) and the phylogenetic tree showed type 1b. Conclusion The mixed infection of type 1a / 1b in Yanbian area was the dominant one, followed by the infection of type 1b and 1b / 2a, which was significantly different from other areas in China. Analysis of 4 cases of type 1a HCV strains found inconsistencies in the classification of HCV 5’NCR and NS5B. It is speculated that it may be the result of natural recombination of HCV genome in the process of biological evolution, but it needs further study to confirm.