Editorial
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. Sep 18, 2015; 7(20): 2241-2244
Published online Sep 18, 2015. doi: 10.4254/wjh.v7.i20.2241
Compartmentalization of hepatitis B virus: Looking beyond the liver
Sibnarayan Datta
Sibnarayan Datta, Molecular Virology Laboratory, Defence Research Laboratory (DRDO), Assam 784001, India
Author contributions: Datta S envisaged the topic and wrote the article.
Supported by The Defence Research and Development Organization (DRDO), Ministry of Defence, Government of India.
Conflict-of-interest statement: The author declares no conflict of interest related to the submitted manuscript.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Sibnarayan Datta, PhD, DRDS, Molecular Virology Laboratory, Defence Research Laboratory (DRDO), Post bag No. 2, Tezpur, Assam 784001, India. sndatta1978@gmail.com
Telephone: +91-3712-258508 Fax: +91-3712-258534
Received: May 28, 2015
Peer-review started: May 30, 2015
First decision: June 18, 2015
Revised: July 8, 2015
Accepted: July 29, 2015
Article in press: August 3, 2015
Published online: September 18, 2015
Processing time: 109 Days and 22.6 Hours
Abstract

Hepatitis B virus (HBV) is classically considered to be hepatotropic, but accumulating evidences strongly support its extra-hepatotropic nature too. HBV nucleic acids and proteins have long been reported in a variety of extra-hepatic tissues. Of these, HBV has been studied in details in the peripheral blood mononuclear cells (PBMCs), due to its accessibility. From these studies, it is now well established that PBMCs are permissive to HBV infection, replication, transcription and production of infective virions. Furthermore, molecular evolutionary studies have provided definite evidences towards evolution of HBV genome in PBMCs, which is independent of evolution occurring in the liver, leading to the emergence and selection of compartment specific escape variants or drug resistant strains. These variants/resistant strains of HBV remain restricted within the PBMCs and are rarely detected in the serum/plasma. In addition, HBV infected PBMCs have been reported to be directly transmitted through intrauterine modes, and this infection does not correlate significantly with serum HBV surface antigen or HBV DNA markers. This editorial briefly reviews the current knowledge on this topic, emphasizes and delineates the gaps that are required to be filled to properly understand the biological and clinical relevance of extrahepatic tropism of HBV.

Keywords: Lymphotropism; Compartmentalization; Hepatitis B virus; Peripheral blood mononuclear cell; Genotype

Core tip: This editorial discusses the phenomenon of compartmentalization of hepatitis B virus (HBV) in the peripheral blood mononuclear cells, their clinical relevance in emergence of escape mutants/drug resistant strains and also in transmission of infection through intrauterine routes. Referring to findings reported in some of the recently published articles on this topic, possible implications of compartmentalization is discussed with a focus on knowledge gaps that need to be filled to better understand HBV biology and pathology.