Sy B T, Nguyen H M, Toan N L, Song L H, Tong H V, Wolboldt C, Binh V Q, Kremsner P G, Velavan T P, Bock C-T
Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany; Vietnam Military Medical University, Ha Noi, Viet Nam.
J Viral Hepat. 2015 Jan;22(1):55-63. doi: 10.1111/jvh.12228. Epub 2014 Feb 18.
Hepatitis D virus (HDV) infection is acquired as a co- /superinfection of Hepatitis B virus (HBV) and can modulate the pathophysiology of chronic hepatitis B and related liver diseases including hepatocellular carcinoma. Among the eight distinct HDV genotypes reported, relatively few studies have attempted to investigate the prevalence of HDV mixed genotypes and RNA recombination of HDV. With a recorded prevalence of 10-20% HBV infection in Vietnam, this study investigated the HDV variability, HDV genotypes and HDV recombination among twenty-one HDV isolates in Vietnamese HBsAg-positive patients. HDV subgenomic and full-length genome sequences were obtained using newly established HDV-specific RT-PCR techniques. The nucleotide homology was observed from 74.6% to 99.4% among the investigated full-length genome of the HDV isolates. We observed HDV genotype 1 and HDV genotype 2 in the investigated Vietnamese patients. Although no HDV genotype mixtures were observed, we report here a newly identified recombinant of HDV genotypes (HDV 1 and HDV 2). The identified recombinant HDV isolate C03 revealed sequence homology to both HDV genotype 1 (nt1 to nt907) and HDV genotype 2 (nt908 to nt1675; HDAg coding region) with a breakpoint at nt908. Our findings demonstrate the prevalence of intergenotypic recombination between HDV genotypes 1 and 2 in a Vietnamese HBsAg-positive patient. Extended investigation on the distribution and prevalence of HDV, HDV mixed genotypes and recombinant HDV genotypes in a larger Vietnamese population offers vital insights into understanding of the micro-epidemiology of HDV and subsequent pathophysiology in chronic HBV- /HDV-related liver diseases.
丁型肝炎病毒（HDV）感染是在乙型肝炎病毒（HBV）合并/重叠感染时获得的，并且可以调节慢性乙型肝炎及包括肝细胞癌在内的相关肝脏疾病的病理生理过程。在已报道的8种不同的HDV基因型中，相对较少的研究试图调查HDV混合基因型的流行情况以及HDV的RNA重组。越南记录的HBV感染率为10%-20%，本研究调查了越南HBsAg阳性患者中21株HDV分离株的HDV变异性、HDV基因型及HDV重组情况。使用新建立的HDV特异性RT-PCR技术获得了HDV亚基因组和全长基因组序列。在所研究的HDV分离株全长基因组中，核苷酸同源性在74.6%至99.4%之间。我们在研究的越南患者中观察到了HDV基因型1和HDV基因型2。虽然未观察到HDV基因型混合情况，但我们在此报告一种新鉴定的HDV基因型重组体（HDV 1和HDV 2）。鉴定出的重组HDV分离株C03在nt1至nt907与HDV基因型1、nt908至nt1675（HDAg编码区）与HDV基因型2均显示出序列同源性，断点位于nt908。我们的研究结果表明，在一名越南HBsAg阳性患者中存在HDV基因型1和2之间的基因型间重组。对更大规模越南人群中HDV、HDV混合基因型及重组HDV基因型的分布和流行情况进行进一步调查，对于理解HDV的微观流行病学以及慢性HBV/HDV相关肝脏疾病随后的病理生理学具有重要意义。
