Role of peripheral blood mononuclear cell transportation from mother to baby in HBV intrauterine infection

Can newborn infants with positive HIV soon after birth be diagnosed with intrauterine infection?

BACKGROUND

Mother-to-child transmission (MTCT) of human immunodeficiency virus (HIV) can occur intrauterine, intrapartum, and postpartum. Currently, infants with confirmed positive results in virological tests before 48 h of age are defined as having intrauterine infection.

AIM

We herein review the literature that identifies emerging challenges in diagnosing intrauterine HIV infection to rethink the current diagnostic criteria.

FINDINGS

A number of reports have shown that some infants who were diagnosed with intrauterine HIV infection after birth became negative for HIV in the subsequent follow-ups, including negative HIV antibodies at the age of 12-18 months. Such "clearance" of HIV was attributed to various reasons: neonatal antiretroviral treatment (ART), false positivity, strong host immune response, or unknown factors in maternal breast milk.

DISCUSSIONS

Positive HIV tests in newborn infants shortly after birth do not necessarily indicate HIV infection, because maternal HIV can enter fetal circulation intrapartum due to the repetitive, strong uterine contractions. The infants are therefore exposed to, but may not yet be infected with HIV at that time. The current diagnostic criteria cannot differentiate HIV exposure from HIV infection, leading to so-called "challenges in diagnosing intrauterine HIV infection". Those infants diagnosed with intrauterine infection who cleared HIV later were less likely to have been truly infected with HIV, but more likely to have been exposed to HIV. Moreover, we suggest that the determination of HIV antibody titers in infants' serial serum samples can provide valuable information to distinguish intrapartum exposure from intrauterine infection.

Maternal A90V mutation in the PreS1 gene of sub-genotype C2 hepatitis B virus is associated with intrauterine transmission

PreS/S gene mutations could impact virus secretion, infection and immune evasion. However, the relationship between PreS/S mutations and intrauterine transmission has not yet been clarified. Thus, we aimed to explore the associations between PreS/S gene mutations of HBV isolated from mothers and intrauterine transmission. We analyzed the mutations of PreS/S regions of the HBV genome in mothers with HBV DNA levels ≥ 106 IU/mL whose neonates experienced HBV intrauterine transmission (transmission group, GT) and those whose neonates did not experience intrauterine transmission (control group, GC) analyzed using clone-based sequencing. In total, 206 sequences were successfully amplified, including 98 sequences (from 21 mothers) from GT and 108 sequences (from 20 mothers) from GC of genotype C for mutational analysis. Among the 1203 nucleotides of PreS/S regions, there were 219 (18.20%) base substitutions, of which 103 (47.03%) base mutations caused amino acid changes. F80S, A90V and I68T were mutation hotspots. Mothers in GT had a higher mutation rate of A90V in the PreS1 gene than mothers in GC. The A90V mutation increased the risk of HBV intrauterine transmission after adjusting the maternal age and the mode of delivery (OR = 6.23, 95% CI: 1.18-32.97). Moreover, the area under the ROC curve (AUC) for intrauterine transmission due to A90V and a combination of A90V with the mode of delivery were 0.723 (95% CI: 0.575 to 0.891, P = 0.011) and 0.848 (95% CI: 0.723 to 0.972, P < 0.001), respectively. Mothers with the A90V mutation in the PreS1 gene may be a potential risk factor for HBV intrauterine transmission.

Vertical Transmission of Hepatitis B Virus-An Update

Hepatitis B virus (HBV) infection is a major public health problem in the world. Approximately 296 million people are chronically infected. In endemic areas, vertical transmission is a common route of transmission. There are several strategies for the prevention of HBV vertical transmission, such as antiviral treatment during the third trimester of pregnancy and immunoprophylaxis to newborns that includes the administration of hepatitis B immune globulin (HBIG) and an HBV vaccine. Despite this, immunoprophylaxis failure can occur in up to 30% of infants born to HBeAg-positive mothers and/or with high viral load. Therefore, management and prevention of HBV vertical transmission is of paramount significance. In this article, we provided a review of the epidemiology, mechanisms of pathogenesis and risk factors of vertical transmission, as well as the strategies implemented to prevent the infection.

New insights into hepatitis B virus lymphotropism: Implications for HBV-related lymphomagenesis

HBV is one of the most widespread hepatitis viruses worldwide, and a correlation between chronic infection and liver cancer has been clearly reported. The carcinogenic capacity of HBV has been reported for other solid tumors, but the largest number of studies focus on its possible lymphomagenic role. To update the correlation between HBV infection and the occurrence of lymphatic or hematologic malignancies, the most recent evidence from epidemiological and in vitro studies has been reported. In the context of hematological malignancies, the strongest epidemiological correlations are with the emergence of lymphomas, in particular non-Hodgkin’s lymphoma (NHL) (HR 2.10 [95% CI 1.34-3.31], p=0.001) and, more specifically, all NHL B subtypes (HR 2.14 [95% CI 1.61-2.07], p&lt;0.001). Questionable and unconfirmed associations are reported between HBV and NHL T subtypes (HR 1.11 [95% CI 0.88-1.40], p=0.40) and leukemia. The presence of HBV DNA in peripheral blood mononuclear cells has been reported by numerous studies, and its integration in the exonic regions of some genes is considered a possible source of carcinogenesis. Some in vitro studies have shown the ability of HBV to infect, albeit not productively, both lymphomonocytes and bone marrow stem cells, whose differentiation is halted by the virus. As demonstrated in animal models, HBV infection of blood cells and the persistence of HBV DNA in peripheral lymphomonocytes and bone marrow stem cells suggests that these cellular compartments may act as HBV reservoirs, allowing replication to resume later in the immunocompromised patients (such as liver transplant recipients) or in subjects discontinuing effective antiviral therapy. The pathogenetic mechanisms at the basis of HBV carcinogenic potential are not known, and more in-depth studies are needed, considering that a clear correlation between chronic HBV infection and hematological malignancies could benefit both antiviral drugs and vaccines.

Hepadnaviral Lymphotropism and Its Relevance to HBV Persistence and Pathogenesis

Since the discovery of hepatitis B virus (HBV) over five decades ago, there have been many independent studies showing presence of HBV genomes in cells of the immune system. However, the nature of HBV lymphotropism and its significance with respect to HBV biology, persistence and the pathogenesis of liver and extrahepatic disorders remains underappreciated. This is in contrast to studies of other viral pathogens in which the capability to infect immune cells is an area of active investigation. Indeed, in some viral infections, lymphotropism may be essential, and even a primary mechanism of viral persistence, and a major contributor to disease pathogenesis. Nevertheless, there are advances in understanding of HBV lymphotropism in recent years due to cumulative evidence showing that: (i) lymphoid cells are a reservoir of replicating HBV, (ii) are a site of HBV-host DNA integration and (iii) virus genomic diversification leading to pathogenic variants, and (iv) they play a role in HBV resistance to antiviral therapy and (v) likely contribute to reactivation of hepatitis B. Further support for HBV lymphotropic nature is provided by studies in a model infection with the closely related woodchuck hepatitis virus (WHV) naturally infecting susceptible marmots. This animal model faithfully reproduces many aspects of HBV biology, including its replication scheme, tissue tropism, and induction of both symptomatic and silent infections, immunological processes accompanying infection, and progressing liver disease culminating in hepatocellular carcinoma. The most robust evidence came from the ability of WHV to establish persistent infection of the immune system that may not engage the liver when small quantities of virus are experimentally administered or naturally transmitted into virus-naïve animals. Although the concept of HBV lymphotropism is not new, it remains controversial and not accepted by conventional HBV researchers. This review summarizes research advances on HBV and hepadnaviral lymphotropism including the role of immune cells infection in viral persistence and the pathogenesis of HBV-induced liver and extrahepatic diseases. Finally, we discuss the role of immune cells in HBV diagnosis and assessment of antiviral therapy efficacy.

Asialoglycoprotein receptor expression in placenta of women with Hepatitis B Virus e Antigen (HBeAg) positive and negative

OBJECTIVE

This study aimed to determine the relationship between Asialoglycoprotein receptor (ASGP-R) on the placenta and positivity of HBeAg in the mother's serum.

METHOD

We collected 52 placentas from delivered mothers who have HbsAg-positive serum. The HbsAg-positive serum was then examined for HBeAg-positive and HBeAg-negative. Immunohistochemistry staining was performed on block paraffin sections using monoclonal antibody of ASGP-R.

RESULTS

The expression of ASGP-R of 52 placenta samples demonstrated that 37 samples were scored I, five samples were score II, two samples were score III, and eight samples were score IV. We found that 14 of 52 serum samples were HBeAg-positive and 38 were HBeAg-negative.

CONCLUSION

There is a significant correlation between ASGP-R on the placenta and positivity of HBeAg in the mother's serum. The expression of the ASGP-R could increase the risk of HBV transmission. The result of this study could be used as a guideline for preventing and therapeutic approach of HBV from mother to child.

Premature Rupture of Membranes with Concurrent Viral Infection

Treatment of viral infections is geared toward ameliorating maternal symptoms and minimizing perinatal transmission. Multidisciplinary teams often are required to manage sequelae due to viral diseases in patients with preterm premature rupture of membranes (PPROM). although data are scarce regarding the antepartum management of common viruses in PPROM, essential principles may be extrapolated from national guidelines and studies in gravid patients. The well-established risks of prematurity are weighed against the often unclear risks of vertical transmission.

Hepatitis B - Vertical transmission and the prevention of mother-to-child transmission

Hepatitis B virus (HBV) infection is the commonest cause of chronic hepatitis, with an estimated global prevalence of 3.5%, and which leads to significant morbidity and mortality. Mother-to-child transmission (MTCT) during pregnancy is the leading form of transmission in endemic populations, and its interruption is thus crucial as the initial step in the elimination of HBV infection, notwithstanding the availability of potent antiviral medications. The risk of MTCT is dramatically reduced by timely neonatal HBV vaccination and the administration of hepatitis B immunoglobulin after birth in high-risk infants. Maternal HBV DNA quantification during pregnancy allows the assessment of the risk of newborn immunoprophylaxis failure (IF). Maternal antiviral treatment in highly viremic women can reduce the risk of IF. However, the optimal HBV DNA cutoff level for the initiation of antiviral treatment remains to be determined.

Hepatitis B and Pregnancy: Virologic and Immunologic Characteristics

The hepatitis B virus (HBV) is an important human pathogen. Unvaccinated infants infected through mother-to-child transmission (MTCT) are at >95% risk of developing serum hepatitis B surface antigen-positive chronic hepatitis B (CHB). Despite complete passive-active HBV immunoprophylaxis, approximately 10% of infants born to mothers who are highly viremic develop CHB, and thus maternal treatment with nucleos(t)ide analogs (tenofovir disoproxil fumarate, lamivudine, or telbivudine) is recommended in the third trimester of pregnancy to reduce MTCT risk. Viral rebound usually occurs after stopping treatment and, in the context of maternal immunologic reconstitution postpartum, can also precipitate host immune-mediated hepatic (biochemical) flares. In this article, we review the epidemiology of HBV MTCT, discuss management and potential mechanisms of HBV vertical transmission, and highlight recent studies on virologic and immunologic aspects of hepatitis B in pregnancy and postpartum.

Presence of Precore (C)/C Promoter Mutants in Peripheral Blood Mononuclear Cells of Chronic Hepatitis B (CHB) Carriers During Pregnancy Does Not Correlate with Increased Risk of Liver Disease in 4 Years of Follow-Up

PURPOSE

HBV precore (PC) and basal core promoter (BCP) mutants are associated with liver disease severity, yet have been suggested to protect against HBV vertical transmission. HBV within peripheral blood mononuclear cells (PBMC) has been reported in association with intrauterine HBV infection. We analyzed HBV replication status in PBMC and PC/BCP mutants in PBMC from pregnant chronic hepatitis B (CHB) patients.

METHODS

Pregnant CHB carriers were assessed for HBeAg, HBV-DNA, ALT in second-third trimester and liver stiffness measurement (LSM) postpartum. HBV-DNA, HBV-cccDNA, and HBV-mRNA were tested in PBMC by in-house PCR. BCP/PC variants were determined by Sanger sequencing and analyzed using MEGA7.

RESULTS

In 37 CHB pregnant carriers, median age 32 years, 53% Asian, median ALT 19 versus 26 U/L, median HBV-DNA 2.6 versus 8.1 logIU/mL (untreated vs. treated), eight HBeAg⁺, with genotype 10%A, 29%B, 21%C, 10%D, 19%E, eight received tenofovir in pregnancy to reduce vertical transmission risk. HBV-DNA was detected in ~ 55% (25/45) PBMC, and PC/BCP mutations were found in 36% (9/25) and 4% (1/25), respectively. All infants received HBV immunoprophylaxis and tested HBV surface antigen negative at 9-12 months of age. During a median 4 years (IQR 3-5), follow-up all mothers showed normal LSM, with no significant change in ALT, HBeAg status, or HBV-DNA levels compared to baseline in untreated CHB carriers.

CONCLUSION

In this multiethnic cohort of pregnant CHB carriers, HBV replicative intermediates and PC/BCP mutants were found in significant proportion of PBMC, but were not associated with increased risk of HBV immunoprophylaxis failure or liver disease severity over long-term follow-up.

Maternal HBeAg positivity and viremia associated with umbilical cord blood hepatitis B viremia

BACKGROUND

Hepatitis B (HBV) transmission may result from in utero transmission. We aimed to determine the correlation between maternal serum and umbilical cord blood HBV DNA levels in infants delivered by chronic HBV-infected mothers and to describe the effect of cord blood viremia on vertical transmission.

METHODS

A prospective cohort of 92 chronic HBV-infected mother-and-child pairs recruited over three years was analyzed. Maternal and cord blood were tested for HBV DNA by real-time PCR. Standard immunoprophylaxis with both active and passive immunization was administered to all infants. Serological testing was performed on all infants at 9 months of age.

RESULTS

Moderate positive correlation of the maternal HBV DNA with cord blood HBV DNA was demonstrated (r² = 0.521, p = <0.001). HBeAg +ve mothers were younger with higher HBV and cord viremia. At 9 months of age, one infant was infected. Infants delivered by HBeAg positive mothers and mothers with high HBV DNA of more than 6 LOG IU/mL (1 x 10⁶ IU/mL) have increased relative risk of cord blood viremia.

CONCLUSIONS

Maternal HBV DNA and presence of HBeAg were positively correlated to cord blood HBV DNA in infants delivered by chronic HBV-infected mothers. Our data suggest that reducing maternal viremia during the antenatal period may help to reduce cord blood viremia.

Presence of hepatitis B virus markers in umbilical cord blood: Exposure to or infection with the virus?

BACKGROUND

We aimed to clarify whether presence of hepatitis B virus (HBV) markers in cord blood indicates exposure to or infection with HBV.

METHODS

We prospectively recruited HBsAg-positive pregnant women and their neonates 2012 through 2015. All neonates received postnatal immunoprophylaxis. The infants were followed up at 7-14 months of age.

RESULTS

Totally 329 HBsAg-positive pregnant women and 333 neonates were enrolled. No cord blood was anti-HBc IgM positive. A total of 290 (87.1%) neonates were followed up at 7-14 months of age and 6 (2.1%) of them were infected with HBV. Of 146 neonates born to HBeAg-negative mothers, 38 (26.0%) and 30 (20.5%) had detectable HBsAg and HBV DNA in cord blood respectively, but none of 126 infants followed up was infected. Of 187 neonates born to HBeAg-positive mothers, 92 (49.2%) and 79 (42.2%) had detectable HBsAg and HBV DNA in cord blood respectively; 6 (3.7%) of 164 infants followed up were infected. Of seven neonates with HBV DNA > 10⁵ IU/ml in cord blood, four had no infection and three others were infected.

CONCLUSION

Presence of HBsAg and/or HBV DNA, even at high levels, in cord blood just indicates exposure to, but not infection with HBV. Presence of HBV markers in cord blood cannot define intrauterine infection.

Incidence and Risk Factors of Intrauterine Transmission Among Pregnant Women With Chronic Hepatitis B Virus Infection

GOALS

To identify the potential risk factors of hepatitis B virus (HBV) intrauterine transmission and predict the incidence of HBV intrauterine transmission among hepatitis B surface antigen-positive pregnant women with diverse viral load.

BACKGROUND

The intrauterine transmission of HBV significantly contributes to the persistence of a high number of patients infected with HBV. However, its risk factors remain unclear.

MATERIALS AND METHODS

A prospective study was performed on hepatitis B surface antigen-positive pregnant women who delivered from June 2012 to December 2016 at Wuhan Medical Care Center for Women and Children, Wuhan, China.

RESULTS

In total, 1200 women paired with 1219 infants were enrolled. In total, 11 (0.9%) infants were identified with intrauterine transmission. We observed that all infants with intrauterine transmission were born to hepatitis B e antigen-positive mothers who had serum HBV DNA levels >7 log10 copies/mL. Our study suggested that the HBV DNA levels (for each log10 copies/mL increase, odds ratio=5.43; 95% confidence interval, 1.31-22.43; P=0.019) had independent effects on HBV intrauterine transmission in a multivariate logistic regression model. Moreover, cesarean section (odds ratio=0.18; 95% confidence interval, 0.04-0.74; P=0.018) was associated with a reduced risk of HBV intrauterine transmission. The predictive rates of intrauterine transmission were 0.06%, 0.50%, 2.81%, 8.89% in infants with maternal HBV DNA levels of 10, 10, 10, 10 copies/mL, respectively.

CONCLUSIONS

Our data confirmed that increasing maternal viral load has the ability to predict intrauterine HBV transmission. Vaginal delivery increased risk of HBV transmission in infants compared with cesarean section. Further studies are warranted to clarify the possible mechanism underlying these associations.

Impact of HBV replication in peripheral blood mononuclear cell on HBV intrauterine transmission

This study determined the effect of hepatitis B virus (HBV) replication in peripheral blood mononuclear cell (PBMC) from HBsAg-positive mothers on HBV intrauterine transmission. A total of 150 HBsAg-positive mothers and their neonates were recruited in this study. Within 24 h after birth, HBV serological markers, serum HBV DNA, PBMC HBV relaxed circular DNA (rcDNA), and covalently closed circular DNA (cccDNA) were measured in the HBsAg-positive mothers and their neonates before passive-active immune prophylaxis. The relationship between HBV replication in PBMC and HBV intrauterine transmission was examined through Chisquare test and logistic regression. The rate of HBV intrauterine transmission was 8.00% (12/150) in the 150 neonates born to HBsAg-positive mothers. The positivities of PBMC HBV rcDNA and cccDNA in the HBsAg-positive mothers were 36.67% (55/150) and 10% (15/150), respectively. Maternal PBMC HBV cccDNA was a risk factor of HBV intrauterine transmission (OR = 6.003, 95% CI: 1.249-28.855). Maternal serum HBeAg was a risk factor of PBMC HBV rcDNA (OR = 3.896, 95% CI: 1.929-7.876) and PBMC HBV cccDNA (OR = 3.74, 95% CI: 1.186-11.793) in the HBsAg-positive mothers. Administration of hepatitis B immune globulin was a protective factor of PBMC HBV cccDNA (OR = 0.312, 95%CI: 0.102-0.954) during pregnancy. The positivity of PBMC HBV rcDNA was related to that of cccDNA in the HBsAg-positive mothers (χ ²= 5.087, P = 0.024). This study suggests that PBMC is a reservoir of HBV and an extrahepatic site for virus replication and plays a critical role in HBV intrauterine transmission.

Detection of Hepatitis B Virus (HBV) Genomes and HBV Drug Resistant Variants by Deep Sequencing Analysis of HBV Genomes in Immune Cell Subsets of HBV Mono-Infected and/or Human Immunodeficiency Virus Type-1 (HIV-1) and HBV Co-Infected Individuals

The hepatitis B virus (HBV) and the human immunodeficiency virus type 1 (HIV-1) can infect cells of the lymphatic system. It is unknown whether HIV-1 co-infection impacts infection of peripheral blood mononuclear cell (PBMC) subsets by the HBV. Aims To compare the detection of HBV genomes and HBV sequences in unsorted PBMCs and subsets (i.e., CD4+ T, CD8+ T, CD14+ monocytes, CD19+ B, CD56+ NK cells) in HBV mono-infected vs. HBV/HIV-1 co-infected individuals. Methods Total PBMC and subsets isolated from 14 HBV mono-infected (4/14 before and after anti-HBV therapy) and 6 HBV/HIV-1 co-infected individuals (5/6 consistently on dual active anti-HBV/HIV therapy) were tested for HBV genomes, including replication indicative HBV covalently closed circular (ccc)-DNA, by nested PCR/nucleic hybridization and/or quantitative PCR. In CD4+, and/or CD56+ subsets from two HBV monoinfected cases, the HBV polymerase/overlapping surface region was analyzed by next generation sequencing. Results All analyzed whole PBMC from HBV monoinfected and HBV/HIV coinfected individuals were HBV genome positive. Similarly, HBV DNA was detected in all target PBMC subsets regardless of antiviral therapy, but was absent from the CD4+ T cell subset from all HBV/HIV-1 positive cases (P<0.04). In the CD4+ and CD56+ subset of 2 HBV monoinfected cases on tenofovir therapy, mutations at residues associated with drug resistance and/or immune escape (i.e., G145R) were detected in a minor percentage of the population. Summary HBV genomes and drug resistant variants were detectable in PBMC subsets from HBV mono-infected individuals. The HBV replicates in PBMC subsets of HBV/HIV-1 patients except the CD4+ T cell subpopulation.

Compartmentalization of hepatitis B virus: Looking beyond the liver

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.

Clinical relevance of hepatitis B virus variants

The hepatitis B virus (HBV) is a global public health problem with more than 240 million people chronically infected worldwide, who are at risk for end-stage liver disease and hepatocellular carcinoma. There are an estimated 600000 deaths annually from complications of HBV-related liver disease. Antiviral therapy with nucleos/tide analogs (NA) targeting the HBV polymerase (P) can inhibit disease progression by long-term suppression of HBV replication. However, treatment may fail with first generation NA therapy due to the emergence of drug-resistant mutants, as well as incomplete medication adherence. The HBV replicates via an error-prone reverse transcriptase leading to quasispecies. Due to overlapping open reading frames mutations within the HBV P can cause concomitant changes in the HBV surface gene (S) and vice versa. HBV quasispecies diversity is associated with response to antiviral therapy, disease severity and long-term clinical outcomes. Specific mutants have been associated with antiviral drug resistance, immune escape, liver fibrosis development and tumorgenesis. An understanding of HBV variants and their clinical relevance may be important for monitoring chronic hepatitis B disease progression and treatment response. In this review, we will discuss HBV molecular virology, mechanism of variant development, and their potential clinical impact.

Hepatitis B virus (HBV) variants fluctuate in paired plasma and peripheral blood mononuclear cells among patient cohorts during different chronic hepatitis B (CHB) disease phases

Hepatitis B virus is classically considered a hepatotropic virus but also infects peripheral blood mononuclear cells. Chronic hepatitis B has different disease phases modulated by host immunity. We compared HBV variability, drug resistance and immune escape mutations in the overlapping HBV polymerase/surface gene in plasma and peripheral blood mononuclear cells in different disease phases. Plasma and peripheral blood mononuclear cells were isolated from 22 treatment naïve patient cohorts (five inactive, six immune-active, nine HBeAg negative and two immune-tolerant). HBV was genotyped via line probe assay, hepatitis B surface antigen titres were determined by an in-house immunoassay, and HBV DNA was quantified by kinetic PCR. The HBV polymerase/surface region, including full genome in some, was PCR-amplified and cloned, and ~20 clones/sample were sequenced. The sequences were subjected to various mutational and phylogenetic analyses. Clonal sequencing showed that only three of 22 patients had identical HBV genotype profiles in both sites. In immune-active chronic hepatitis B, viral diversity in plasma was higher compared with peripheral blood mononuclear cells. Mutations at residues, in a minority of clones, associated with drug resistance, and/or immune escape were found in both compartments but were more common in plasma. Immune escape mutations were more often observed in the peripheral blood mononuclear cells of immune-active CHB carriers, compared with other disease phases. During all CHB disease phases, differences exist between HBV variants found in peripheral blood mononuclear cells and plasma. Moreover, these data indicate that HBV evolution occurs in a compartment and disease phase-specific fashion.