Department of Microbiology, All India Institute of Medical Sciences, Bhopal, India.
Department of Molecular and Cellular Medicine, Institute of Liver and Biliary Sciences, New Delhi, India.
Sci Rep. 2022 Oct 22;12(1):17795. doi: 10.1038/s41598-022-22699-8.
The transplacental route of vertical transmission of Hepatitis B Virus (HBV) has been known for over a decade. Here we present evidence which suggest HBV can replicate in placenta. Forty-one HBsAg positive and 10 control pregnant women were enrolled in the study after obtaining informed consent. HBV positives were further divided in the High Viral Load (HVL) Group and Low Viral Load (LVL) Group according to INASL guidelines 2018. The Presence of the HBV DNA and expression of NTCP in the placenta was analyzed by qPCR/RT-qPCR and/or immunohistochemistry (IHC). The presence of cccDNA was assessed using Digital Droplet PCR while the presence of pre-genomic (pg) RNA was assessed through qRT-PCR and sequencing. The presence of HBeAg and HBcAg in the placenta was assessed by IHC. Immunostaining of NTCP, HBeAg and HBcAg on trophoblasts along with the presence of total HBV DNA, cccDNA and pgRNA indicated, that these cells are not only susceptible to HBV infection but may also support viral replication. This is further supported by the finding that trophoblasts of the several HBeAg seronegative samples harbored the HBeAg. Although, we did not find any correlation in NTCP expression and viral markers with viral load indicates placental replication may not aping hepatocytes. The presence of the HBV receptor, NTCP along with the presence of cccDNA, pgRNA, and HBeAg in placenta of HBV infected females without circulating HBeAg suggest that placenta act as a replication host.
乙型肝炎病毒（HBV）的胎盘垂直传播途径已经被人们了解了十余年。在这里，我们提供了证据表明 HBV 可以在胎盘内复制。在获得知情同意后，我们纳入了 41 名 HBsAg 阳性和 10 名对照孕妇。根据 2018 年 INASL 指南，HBV 阳性孕妇进一步分为高病毒载量（HVL）组和低病毒载量（LVL）组。通过 qPCR/RT-qPCR 和/或免疫组化（IHC）分析胎盘内 HBV DNA 的存在和 NTCP 的表达。通过数字液滴 PCR 评估 cccDNA 的存在，通过 qRT-PCR 和测序评估前基因组（pg）RNA 的存在。通过 IHC 评估胎盘内 HBeAg 和 HBcAg 的存在。对滋养层细胞上的 NTCP、HBeAg 和 HBcAg 的免疫染色，以及总 HBV DNA、cccDNA 和 pgRNA 的存在表明，这些细胞不仅容易受到 HBV 感染，而且可能支持病毒复制。这一发现进一步表明，在几个 HBeAg 血清阴性样本的滋养层细胞中存在 HBeAg。尽管我们没有发现 NTCP 表达和病毒标志物与病毒载量之间存在任何相关性，但这表明胎盘复制可能并不依赖于肝细胞。HBV 感染女性的胎盘存在 HBV 受体 NTCP 以及 cccDNA、pgRNA 和 HBeAg 的存在，表明胎盘可以作为复制宿主。
