Virological and Clinical Characteristics of Hepatitis B Virus Genotype A
Virological and Clinical Characteristics of Hepatitis B Virus Genotype A
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DOI：
10.1007/s00535-017-1367-5
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发表时间：
2017
影响因子：
6.3
通讯作者：
Kiyoaki Ito;M. Yoneda;K. Sakamoto;M. Mizokami
中科院分区：
文献类型：
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作者：
Kiyoaki Ito;M. Yoneda;K. Sakamoto;M. Mizokami
B型肝炎病毒（HBV）感染是人类最普遍的慢性病毒感染之一。据报告，B型肝炎表面抗原（HBsAg）的总患病率为3.6%;然而，其因地理区域而异。根据组间基因组差异> 8%，HBV分为10种基因型（A至J）。具体而言，HBV基因型A表现出几种独特的病毒学和临床特征，并可进一步分为七种亚型。其中A2或Ae亚型（A2/[e]）是院内感染的主要病原体，也是男性同性恋者的主要病原体。关于病毒学因素，在基因型A中很少观察到G1896 A前C突变，因为它会破坏前基因组RNA包装所必需的ε信号中的基本茎环结构。HBV基因型A还在乙型肝炎e抗原（HBeAg）前体中含有6个核苷酸的C-末端插入，导致在阳性患者的血清中观察到可变长度的HBeAg蛋白产物。这些分子特征可能有助于基因型A感染患者的特定临床表现，如轻度急性B型肝炎（AHB），AHB中HBsAg阳性持续时间较长，以及成人AHB后慢性化增加。然而，在慢性B型肝炎患者中，A基因型对干扰素的反应比其他基因型更好。在这里，我们回顾了HBV基因型A的病毒学和临床特征，这将有助于阐明持续性病毒感染，宿主遗传因素和治疗之间的关系，在未来的研究。
Hepatitis B virus (HBV) infection is one of the most prevalent chronic viral infections in humans. The overall prevalence of hepatitis B surface antigen (HBsAg) is reported to be 3.6%; however, it varies depending upon the geographic area. HBV is classified into ten genotypes (A through J) on the basis of an intergroup genomic divergence of > 8%. Specifically, HBV genotype A exhibits several unique virological and clinical characteristics and can be further classified into seven subtypes. Among them, subtype A2 or Ae (A2/[e]) isoccasionallyresponsible for nosocomial infection and among homosexual males. Regarding virological factors, the G1896A precore mutation is rarely observed in genotype A as it would disrupt an essential stem-loop structure in the ε signal essential for pregenomic RNA packaging. HBV genotype A also harbors a 6-nucleotide C-terminal insertion in the hepatitis B-e antigen (HBeAg) precursor, resulting in a variable-length HBeAg protein product observed in serum of positive patients. These molecular traits likely contribute to the specific clinical presentation of genotype A-infected patients, such as mild acute hepatitis B (AHB), longer persistence of HBsAg positivity in AHB, and increased chronicity after AHB in adults. However, genotype A shows a better response to interferon than other genotypes in chronic hepatitis B patients. Here, we review the virological and clinical characteristics of HBV genotype A that will be useful in elucidating the association among persistent viral infection, host genetic factors, and treatment in future studies.