中国东北部延边地区丙型肝炎病毒1a型感染研究

The distribution of hepatitis C virus genotype la in Yanbian area

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 Hepatitis C Virus （HCV）genotype l a in Yanbian area, Jilin province. Methods The genotypes of the serum specimens of 47 patients with HCV from Yanbian area were determined by Scheme ABC of RFLP based on HCV 5＇ noncoding region （5＇NCR）. The samples of type la （Y2, Y4, Y6, and Y8） were amplified from the 5＇NCR and NS5B regions by RT- PCR, and then sequenced directly. These sequences were subjected to phylogenetic analysis with 27 reference sequences of HCV complete genomes from GenBank. Results 44 specimens were HCV RNA positive, among which 19 specimens （43.2%） were of the type 1a/1b , 12 （27.3 % ） were of the type 1b, 8 （18.2%） were of the type 2a/1b, 4 （9.1%） were of the type 1a, and 1 （2.3 % ） was of the type 2a, however, the genotypes 2b and 3 - 6 lacked. The phylogenetic analysis for 1 a samples showed that according to 5＇NCR they belonged to type la, while on NS5B belonging to type lb. The most nucleotide identity of 5＇ NCR was respectively 0. 990, 0.990, 0.990, and 0.990 between Y2, Y4, Y6, Y8 and the isolate HC-J1 （genotype 1a）, while that of NS5B was respectively 0.936, 0.957, 0.936, and 0.936 between Y2, Y4, Y6, Y8 and the isolate HC-J4 （genotype 1 b ）. Conclusion In Yanbian area the distribution of HCV genotype is different from those in other areas and 1a/1b has even replaced 1b as the most HCV genotype here. The results of genotyping 1a on 5＇NCR and NS5B are completely inconsistent. This phenomenon may be the consequence of recombination in evolution.