Association of Hepatitis B Core-Related Antigen With Hepatitis B Virus Reactivation in Occult Viral Carriers Undergoing High-Risk Immunosuppressive Therapy

What is new on HBsAg and other diagnostic markers in HBV infection?

Challenges in the management of chronic hepatitis B virus (HBV) infection involve the prediction of the natural course to identify patients who require antiviral therapy and the prediction of functional cure as ultimate goal of antiviral therapy. HBV DNA as marker for viral replication is important but not sufficient for an adequate management of patients with chronic HBV infection. Data on the quantification of additional HBV marker such as hepatitis B surface antigen (HBsAg), hepatitis B core-related antigen (HBcrAg) and hepatitis B virus RNA (HBV RNA) have accumulated in recent years. Here we review the current evidence how to use these markers and discuss open issues that require additional research.

Hepatitis B infection acquired after haematopioetic stem cell transplant through horizontal mode

A 22 month old child with thalassaemia major received unrelated umbilical cord blood transplantation. She was born to mother of HBsAg carrier and received hepatitis B immunoglobulin at birth and hepatitis B vaccination. She was HBsAg negative and anti-HBs positive before transplantation. After transplant, she was taken care by her mother and found to be HBsAg positive at 2 year post-transplant. Genotyping of the mother's and child's HBV status confirmed to be of same genotype and demonstrated horizontal transmission in post-transplant setting. Passive immunization of HBV may be considered in early post-transplant phase to prevent horizontal transmission of HBV, and antiviral treatment of the carer should be offered to prevent transmission of infection to immunocompromised child.

The use of biologics in pregnant patients with rheumatic disease

INTRODUCTION

An increasing number of female patients with autoimmune diseases are treated with biologic drugs. Concerns in regard to safety of biologics during pregnancy arise in patients who have not completed their families. Areas covered: A review of the literature dealing with child outcomes of pregnancies exposed to biologics shows that TNF inhibitors (TNFi) are the best studied in regard to human pregnancy. In studies comparing exposed pregnancies to disease-matched controls no increased risk of spontaneous abortion, low birth weight, prematurity or congenital malformations has been observed. For rituximab, tocilizumab, anakinra, belimumab and ustekinumab no prospective, controlled studies are available, and firm conclusions about their safety during pregnancy cannot be drawn. Expert commentary: TNFi appear fairly safe when given in early pregnancy. For biologics other than TNFi prospective, controlled studies on outcomes after early and late pregnancy exposure are urgently needed. Possible effects of TNFi and all other biologics on children's immune function, infection rate and vaccination responses are either limited or absent and need to be extended. Development of laboratory tests to measure concentrations of biologics routinely in children exposed in utero would facilitate decisions in regard to the time point of vaccination with live vaccines.

Complete and Incomplete Hepatitis B Virus Particles: Formation, Function, and Application

Hepatitis B virus (HBV) is a para-retrovirus or retroid virus that contains a double-stranded DNA genome and replicates this DNA via reverse transcription of a RNA pregenome. Viral reverse transcription takes place within a capsid upon packaging of the RNA and the viral reverse transcriptase. A major characteristic of HBV replication is the selection of capsids containing the double-stranded DNA, but not those containing the RNA or the single-stranded DNA replication intermediate, for envelopment during virion secretion. The complete HBV virion particles thus contain an outer envelope, studded with viral envelope proteins, that encloses the capsid, which, in turn, encapsidates the double-stranded DNA genome. Furthermore, HBV morphogenesis is characterized by the release of subviral particles that are several orders of magnitude more abundant than the complete virions. One class of subviral particles are the classical surface antigen particles (Australian antigen) that contain only the viral envelope proteins, whereas the more recently discovered genome-free (empty) virions contain both the envelope and capsid but no genome. In addition, recent evidence suggests that low levels of RNA-containing particles may be released, after all. We will summarize what is currently known about how the complete and incomplete HBV particles are assembled. We will discuss briefly the functions of the subviral particles, which remain largely unknown. Finally, we will explore the utility of the subviral particles, particularly, the potential of empty virions and putative RNA virions as diagnostic markers and the potential of empty virons as a vaccine candidate.