In order to optimally refine the multiple emerging drug targets for hepatitis B virus (HBV), it is vital to evaluate virological and immunological changes at the site of infection. Traditionally liver biopsy has been the mainstay of HBV disease assessment, but with the emergence of non-invasive markers of liver fibrosis, there has been a move away from tissue sampling. Here we argue that liver biopsy remains an important tool, not only for the clinical assessment of HBV but also for research progress and evaluation of novel agents. The importance of liver sampling has been underscored by recent findings of specialised subsets of tissue-resident immune subsets capable of efficient pathogen surveillance, compartmentalised in the liver and not sampled in the blood. Importantly, the assessment of virological parameters, such as cccDNA quantitation, also requires access to liver tissue. We discuss strategies to maximise information obtained from the site of infection and disease pathology. Fine needle aspirates of the liver may allow longitudinal sampling of the local virus/host landscape. The careful utilisation of liver tissue and aspirates in conjunction with blood will provide critical information in the assessment of new therapeutics for the functional cure of HBV.

中文翻译：

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肝脏取样：在功能性治愈的道路上了解 HBV 发病机制的重要窗口

为了优化优化乙型肝炎病毒 (HBV) 的多个新兴药物靶点，评估感染部位的病毒学和免疫学变化至关重要。传统上，肝活检一直是 HBV 疾病评估的中流砥柱，但随着肝纤维化非侵入性标志物的出现，已经远离了组织取样。在这里，我们认为肝活检仍然是一个重要的工具，不仅可以用于 HBV 的临床评估，还可以用于研究进展和评估新药。最近发现的组织驻留免疫亚群的特殊亚群能够有效监测病原体，在肝脏中划分而不在血液中取样，这强调了肝脏取样的重要性。重要的是，病毒学参数的评估，例如 cccDNA 定量，还需要接触肝组织。我们讨论了最大化从感染和疾病病理学部位获得的信息的策略。肝脏的细针抽吸物可能允许对局部病毒/宿主环境进行纵向采样。仔细利用肝组织和抽吸物以及血液，将为评估用于 HBV 功能性治愈的新疗法提供关键信息。