Occult hepatitis B virus infection in Egypt

Genetic diversity and occult hepatitis B infection in Africa: A comprehensive review

BACKGROUND

Occult hepatitis B infection (OBI) is a globally prevalent infection, with its frequency being influenced by the prevalence of hepatitis B virus (HBV) infection in a particular geographic region, including Africa. OBI can be transmitted through blood transfusions and organ transplants and has been linked to the development of hepatocellular carcinoma (HCC). The associated HBV genotype influences the infection.

AIM

To highlight the genetic diversity and prevalence of OBI in Africa.

METHODS

This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and involved a comprehensive search on PubMed, Google Scholar, Science Direct, and African Journals Online for published studies on the prevalence and genetic diversity of OBI in Africa.

RESULTS

The synthesis included 83 articles, revealing that the prevalence of OBI varied between countries and population groups, with the highest prevalence being 90.9% in patients with hepatitis C virus infection and 38% in blood donors, indicating an increased risk of HBV transmission through blood transfusions. Cases of OBI reactivation have been reported following chemotherapy. Genotype D is the predominant, followed by genotypes A and E.

CONCLUSION

This review highlights the prevalence of OBI in Africa, which varies across countries and population groups. The study also demonstrates that genotype D is the most prevalent.

Genetic diversity, haplotype analysis, and prevalence of Hepatitis B virus MHR mutations among isolates from Kenyan blood donors

BACKGROUND

The rapid spread of HBV has resulted in the emergence of new variants. These viral genotypes and variants, in addition to carcinogenic risk, can be key predictors of therapy response and outcomes. As a result, a better knowledge of these emerging HBV traits will aid in the development of a treatment for HBV infection. However, many Sub-Saharan African nations, including Kenya, have insufficient molecular data on HBV strains circulating locally. This study conducted a population-genetics analysis to evaluate the genetic diversity of HBV among Kenyan blood donors. In addition, within the same cohort, the incidence and features of immune-associated escape mutations and stop-codons in Hepatitis B surface antigen (HBsAg) were determined.

METHODS

In September 2015 to October 2016, 194 serum samples were obtained from HBsAg-positive blood donors residing in eleven different Kenyan counties: Kisumu, Machakos, Uasin Gishu, Nairobi, Nakuru, Embu, Garissa, Kisii, Mombasa, Nyeri, and Turkana. For the HBV surface (S) gene, HBV DNA was isolated, amplified, and sequenced. The sequences obtained were utilized to investigate the genetic and haplotype diversity within the S genes.

RESULTS

Among the blood donors, 74.74% were male, and the overall mean age was 25.36 years. HBV genotype A1 (88.14%) was the most common, followed by genotype D (10.82%), genotype C (0.52%), and HBV genotype E (0.52%). The phylogenetic analysis revealed twelve major clades, with cluster III comprising solely of 68 blood donor isolates (68/194-35.05%). A high haplotype diversity (Hd = 0.94) and low nucleotide diversity (π = 0.02) were observed. Kisumu county had high number of haplotypes (22), but low haplotype (gene) diversity (Hd = 0.90). Generally, a total of 90 haplotypes with some consisting of more than one sequence were observed. The gene exhibited negative values for Tajima's D (-2.04, p<0.05) and Fu's Fs (-88.84). Several mutations were found in 139 isolates, either within or outside the Major Hydrophilic Area (MHR). There were 29 mutations found, with 37.9% of them situated inside the "a" determinant. The most common mutations in this research were T143M and K122R. Escape mutations linked to diagnostic failure, vaccination and immunoglobulin treatment evasion were also discovered. Also, one stop-codon, W163STP, inside the MHR, was found in one sample from genotype A.

CONCLUSION

In Kenya, HBV/A1 is still the most common genotype. Despite limited genetic and nucleotide diversity, haplotype network analysis revealed haplotype variance among HBV genotypes from Kenyan blood donors. The virological properties of immune escape, which may be the source of viral replication endurance, were discovered in the viral strains studied and included immune-escape mutations and stop-codon. The discovery of HBsAg mutations in MHR in all isolates highlighted the need of monitoring MHR mutations in Kenya.

Rate of occult hepatitis B virus infection among individuals with tuberculosis in northeastern Iran: A molecular epidemiological study

One third of the world population has a history of exposure to the hepatitis B virus (HBV), and two billion people are infected with latent tuberculosis (TB). Occult hepatitis B infection (OBI) is defined as the presence of replicative-competent HBV DNA in the liver with detectable or undetectable HBV DNA in the serum of individuals testing negative for the HBV surface antigen (HBsAg). Screening with HBV DNA could identify OBI and significantly reduce carriers and complications of chronic hepatitis B (CHB). This study aims to assess HBV serological markers and OBI molecular diagnosis among people with TB in Mashhad, northeastern Iran. We have performed HBV serological markers (HBsAg, HBc antibodies (Ab) and HBs Ab) in 175 participants. Fourteen HBsAg⁺ sera were excluded for further analysis. The presence of HBV DNA (C, S, and X gene regions) was assessed by the qualitative real-time PCR (qPCR) method. Frequencies of HBsAg, HBc, and HBs Ab were 8% (14/175), 36.6% (64/175), and 49.1% (86/175), respectively. Among these 42.9% (69/161) were negative for all HBV serological markers. The S, C, and X gene regions were positive in 10.3% (16/156), 15.4% (24/156), and 22.4% (35/156) of participants, respectively. The total OBI frequency was estimated at 33.3% (52/156) when based on detecting one HBV genomic region. Twenty-two and 30 participants had a seronegative and seropositive OBI, respectively. Thorough screening of high-risk groups with reliable and sensitive molecular methods could lead to OBI identification and decrease CHB long-term complications. Mass immunization remains critical in preventing, reducing, and potentially eliminating HBV complications.

Prevalence of occult hepatitis B virus infection among patients receiving haemodialysis in Sana'a city

BACKGROUND

Occult hepatitis B virus infection (OBI) is a challenging entity. Due to the increase in invasive procedures, blood transfusions, and difficulties in diagnosing OBI, patients are more likely to acquire OBI. This cross-sectional study was conducted to assess the prevalence of OBI by hepatitis B virus (HBV)-DNA detection, the prevalence of HBV infection by total hepatitis B core antibody (HBcAb) detection, and the potential risk factors for HBV infection in patients receiving haemodialysis regularly.

METHODS

This study included 80 patients receiving haemodialysis regularly, without acute or chronic HBV infection. They were selected from the dialysis units in Sana'a city, Yemen from June 2016 to June 2017. Patients who were positive for hepatitis B surface antigen and hepatitis B surface antibody were excluded from this study. Blood samples were taken prior to each haemodialysis session, and serological markers of HBV were included. HBcAb was measured by enzyme-linked immunosorbent assay, and HBV-DNA was measured by polymerase chain reaction.

RESULTS

HBV-DNA was detected in four patients (5%) and HBcAb was detected in 38 patients (47.5%). There was a significant association between HBV-DNA and HBcAb in patients receiving haemodialysis regularly.

CONCLUSIONS

Patients who test positive for HBcAb should undergo additional HBV-DNA testing to allow accurate HBV screening and prevent infection of other patients.

Occult Hepatitis (B) Infection in Hepatitis (C) Virus Infection Patients after the Treatment with Direct Acting Antiviral Drugs

Background: The prevalence of occult hepatitis B ranges widely in patients with hepatitis C. This may have an impact on treatment of hepatitis C. Aims: The current study aimed to evaluate the prevalence of occult hepatitis B infection in chronic hepatitis C patients who finished the course of treatment with direct acting antiviral drugs and it’s correlation with treatment failure. Setting: Outpatient Clinic of Internal Medicine Department, Faculty of Medicine, Menoufia University, Egypt. Patients and methods: This study was conducted on 900 Egyptian patients chronically infected with HCV. All patients tested positive for serum real time polymerase chain reaction for HCV- RNA and received DAAs therapy for 12 weeks. Patients were categorized to:  Group I: 450 patients with chronic hepatitis C after direct antiviral treatment who responded to treatment. Group II: 450 patients with chronic hepatitis C after direct antiviral treatment who didn’t respond to treatment. All patients were submitted to clinical examination, laboratory investigations and abdominal ultrasonography. Detection of HBV- DNA and HCV- RNA was performed by PCR. Results: The prevalence of OBI detected in sera of HCV patients was 10.6 % (96/900). The present study showed no significant correlation between prevalence of OBI and virologic failure (p-value: 0.084).  There was no statistically significant difference (p-value > 0.05) between the studied groups as regard prevalence of OBI. Conclusion: The prevalence of OBI was 10.6% in patients chronically infected with HCV. OBI doesn't affect the anti-HCV DAAs outcomes.

Global prevalence of occult hepatitis B: A systematic review and meta-analysis

The study aimed to investigate the prevalence and risk factors associated with occult hepatitis B virus (HBV) infection (OBI) in the global population. We searched PubMed, Embase, CINAHL, Cochrane and Web of Science from database inception through 27 Dec, 2018. Studies reporting HBV-DNA serological data in previously undiagnosed hepatitis B patients were included. The data were further categorized according to the presence of risk factors. After an initial screening of 2,325 records, we finally included 98 articles about the prevalence of OBI from 34 countries and regions. The OBI prevalence was 0.82% (95% CI:0.69-0.96) in the general population, 16.26% (95% CI:10.97-22.34) in HIV patients, 13.99% (95% CI:8.33-20.79) in patients with other liver diseases, 4.25% (95% CI:1.64-7.87) in haemodialysis patients and 5.14% (95% CI:2.26-9.01) patients with other risk factors. In conclusion, OBI prevalence varies significantly across different populations and nations, which deserve attention from the public health authorities. Our results generate further epidemiological data to identify the population with OBI, which has important clinical implications in finding these high-risk populations to design preventive and management strategies.

Persistence of Hepatitis B Virus Infection: A Multi-Faceted Player for Hepatocarcinogenesis

Hepatitis B virus (HBV) infection has a multi-dimensional effect on the host, which not only alters the dynamics of immune response but also persists in the hepatocytes to predispose oncogenic factors. The virus exists in multiple forms of which the nuclear localized covalently closed circular DNA (cccDNA) is the most stable and the primary reason for viral persistence even after clearance of surface antigen and viral DNA. The second reason is the existence of pregenomic RNA (pgRNA) containing virion particles. On the other hand, the integration of the viral genome in the host chromosome also leads to persistent production of viral proteins along with the chromosomal instabilities. The interferon treatment or administration of nucleot(s)ide analogs leads to reduction in the viral DNA load, but the pgRNA and surface antigen clearance are a slow process and complete loss of serological HBsAg is rare. The prolonged exposure of immune cells to the viral antigens, particularly HBs antigen, in the blood circulation results in T-cell exhaustion, which disrupts immune clearance of the virus and virus-infected cells. In addition, it predisposes immune-tolerant microenvironment, which facilitates the tumor progression. Thus cccDNA, pgRNA, and HBsAg along with the viral DNA could be the therapeutic targets in the early disease stages that may improve the quality of life of chronic hepatitis B patients by impeding the progression of the disease toward hepatocellular carcinoma.

Current situation of viral hepatitis in Egypt

An estimated 8-10 million people suffer from viral hepatitis in Egypt. Hepatitis A virus (HAV) and hepatitis E virus (HEV) are the major causes of viral hepatitis in Egypt as 50% or more of the Egyptian population are already exposed to HAV infection by the age of 15. In addition, over 60% of the Egyptian population test seropositive for anti-HEV in the first decade of life. HEV mainly causes self-limiting hepatitis; however, cases of fulminant hepatitis and liver failure were reported in Egypt. Hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis D virus (HDV) are the main causes of chronic hepatitis, liver cirrhosis, and liver cancer (hepatocellular carcinoma [HCC]) in Egypt. Globally, Egypt had the highest age-standardized death rate due to cirrhosis from 1990 to 2017. The prevalence rate of HBV (1.3%-1.5%) has declined after national infantile immunization. Coinfection of HBV patients with HDV is common in Egypt because HDV antibodies (IgG) vary in range from 8.3% to 43% among total HBV patients. After the conduction of multiple national programs to control HCV infection, a lower rate of HCV prevalence (4.6%) was recently reported. Data about the incidence of HCV after treatment with direct antiviral agents (DAAs) are lacking. An HCC incidence of 29/1000/year in cirrhotic patients after DAA treatment is reported. A higher rate of infiltrative pattern among HCC patients after DAA treatment is also recognized. Viral hepatitis is one of the major public health concerns in Egypt that needs more attention and funding from health policymakers.

Characterization of Antigen Escape Mutations in Chronic HBV-Infected Patients in Upper Egypt

Background

Mutations within the “a” determinant region (position 124–147) that is present in the major hydrophilic region (MHR, position 99–160) of the hepatitis B surface antigen (HBsAg) are associated with vaccine-escape, lack of diagnosis, and failure to hepatitis B immunoglobulin (HBIG) therapy. Data regarding the amino acid changes of “a” determinant region of HBsAg are limited in Egypt. The prevalence and mutations in this region among chronic HBV (CHB)-infected patients in Upper Egypt are not known.

Material and Methods

Blood samples were collected from HBsAg-positive CHB-infected patients (n=123) admitted to Assiut University Hospitals. Serum samples were screened for HBsAg, HBeAg, anti-HBs and anti-HBe antibodies using commercially available ELISA kits. Viral load was determined by qPCR. In addition, mutational analysis was carried out targeting the HBV surface gene to determine the HBV genotype and vaccine escape mutations.

Results

Sequencing analysis of HBV DNA revealed that genotype D is the major circulating type (81.3%), followed by genotype E (18.7%). Analysis of the HBV genome revealed that 103/123 (83.7%) patients showed wild-type sequences and 20/123 (16.3%) showed mutations in the HBsAg gene. Mutation in seventeen patients (17/20, 85%) showed only one mutation, and three patients showed two mutations (3/20, 15%) in the “a” determinant region. The observed mutations were T115S (3/20, 15%), P120T/S (3/20, 15%), T126S (1/20, 5%), Q129R (2/20, 10%), M133T (2/20, 10%), S143L (5/20, 25%), D144E/A (3/20, 15%), and G145R/A (4/20, 20%). Mutations in the “a” determinant region were detected in genotype D isolates only.

Conclusion

We described for the first time the prevalence and characterization of vaccine escape mutants in CHB patients in Upper Egypt. Mutational analysis of the “a” determinant region revealed the presence of a wide spectrum of mutants in the circulating HBV isolates that could be a potential threat to HBV diagnosis, therapy success, and HBV vaccination program in Upper Egypt.

High Risk of HBV Infection Among Vaccinated Polytransfused Children With Malignancy

AIM OF THE STUDY

The national Egyptian hepatitis B virus (HBV) vaccination program coverage of all infants started in 1992. The study aimed to assess immunity against HBV and occurrence of HBV breakthrough infections in vaccinated polytransfused children with malignancies.

PATIENTS AND METHODS

Eighty-nine polytransfused children with malignancies were recruited; 37 were on chemotherapy (male:female 20:17; mean age 7.7±4.0 y), and there were 52 naive patients (male:female 31:21; mean age 7.6±3.2 y). In addition, 162 age-matched and sex-matched healthy controls were recruited. Patients' sera were tested for quantitative anti-hepatitis B surface (HBs) (enzyme-linked immunoassays technique), hepatitis B surface antigen (HBsAg), total anti-hepatitis B core, and HBV-DNA (nested polymerase chain reaction for surface, core, and x-regions).

RESULTS

There was a significant lower percentage of having protective anti-HBs (10 to 100 IU/L) level among those receiving chemotherapy (13.5%) than those without (44.2%) and controls (32.1%). Twenty-one (67.7%) of those on chemotherapy were HBsAg positive compared with 10 (32.2%) of those without. Overall, 46 patients were HBV-DNA positive; 38 were c-region positive, 5 were s-region positive, 2 positive for the c-region and the s-region, and 1 tested positive for the c-region and the x-region. Of 46 patients, 20 were also positive for HBsAg (overt infection), while 26 had occult HBV infection (HBsAg-negative). Anti-HBs ≥10 IU/L co-existed among 45% of patients with overt infection and in 50% of those with occult infection. There was nonsignificant impact of receiving chemotherapy on the level of HBV-DNA.

CONCLUSIONS

Vaccinated children with malignancies, especially those under chemotherapy, are at a significant risk of HBV infection. The co-existence of anti-HBs with HBsAg and/or HBV-DNA may represent a possible residual transfusion-transmission risk with mutant HBV strains.

Occult hepatitis B in kidney transplants recipients and donors from Western Mexico

BACKGROUND

Occult hepatitis B virus infection (OBI) is defined as the presence of hepatitis B virus (HBV) DNA in serum and/or liver from HBsAg-negative subjects. Our aim was to determine OBI frequency in serum and genomic DNA in patients undergoing renal transplant and their cognate donors in a selected population from Western Mexico.

METHODS

Blood samples were obtained from 94 donors and their cognate recipients (188 participants) before kidney transplantation. Identification of HBV DNA was carried-out by nested (S-region) and semi-nested (Pol-region) PCR in both genomic and serum DNA samples from 188 participants at pre-surgical stage and from a subset of 73 recipients at three-month follow-up.

RESULTS

HBV-DNA was not detected in either genomic or serum DNA samples from recipients or donors prior to transplantation. After three-months of follow-up, 2 out of 73 (2.7%, 95% CI: 0.9-11.9%) recipients were positive to HBV-DNA (Pol-region) in genomic DNA samples using a high sensitivity Taq DNA polymerase.

CONCLUSIONS

OBI incidence in recipients of kidney transplant may be higher than previously recognized. Detection of HBV-DNA was higher in genomic DNA than in serum samples using a high sensitivity Taq DNA polymerase. To the best of our knowledge, this is the first report regarding this specific topic in Mexicans.

Genetic variation in microRNA-100 (miR-100) rs1834306 T/C associated with Hepatitis B virus (HBV) infection: Correlation with expression level

Circulating microRNAs (miRNAs) have a vital role in Hepatitis B virus (HBV) diagnosis and therapeutics. miR-100 was reported to be associated with various aspects of HBV biology. This study focused on a miR-100 Single Nucleotide Polymorphism (SNP) (rs1834306 T/C) and its contribution to an individual's susceptibility and prognosis of HBV infection. The effect of SNP on miR-100 expression will be also evaluated. Two hundred subjects: 100 HBV infected patients and 100 age-and-sex-matched healthy individuals served as a control group. SNP detection was performed using polymerase chain reaction technique with sequence-specific primers (PCR-SSP) method and miR-100 expression through quantitative real-time PCR (qRT-PCR). Our result showed a significant up-regulation of miR-100 expression in HBV patients versus the control group (P < .01). A positive correlation was found between viral load and elevation in miR-100 expression (r = 0.508; P < .01). Concerning miR-100 expression in different genotypes/alleles, TC genotype and T allele in coincides with a significantly elevated expression level of miR-100 (P < .001) in HBV patients than in controls. Best of our knowledge, it is the first observational prospective case-control study concerned with miR-100 (rs1834306 T/C) SNP in the Egyptian population. However, the small size of this preliminary work required more prospective investigations to confirm our data.

Hepatitis B Virus Molecular Epidemiology, Host-Virus Interaction, Coinfection, and Laboratory Diagnosis in the MENA Region: An Update

Hepatitis B virus (HBV) is an enveloped partial double-stranded DNA virus that can cause acute and chronic hepatitis. According to the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC), 257 million people are living with HBV. Moreover, 20,900 acute hepatitis B cases were reported in 2016. Hepatitis B is highly prevalent in the African, Western Pacific, Eastern Mediterranean, South-East Asia, and European regions, respectively. Due to the high mutational rate of HBV and lack of reverse transcriptase proofreading activity, ten different genotypes with different geographical distributions have been identified. HBV pathogenesis and severity of infection depend on several host and viral factors, particularly, the genetic variability of both the host and virus. Although HBV infection is a global health concern, there is a lack of adequate studies and reports in the Middle East and North Africa (MENA) region. Here, we provide a review on HBV epidemiology, pathogenesis, host-pathogen interactions, coinfection with selected viruses, and laboratory diagnosis, focusing on studies conducted in the MENA region to determine the current situation of the HBV infection and outline the future study areas.

Polymorphisms of CYP27B1 are associated with IFN efficacy in HBeAg-positive patients

BACKGROUND

Host single nucleotide polymorphisms were associated with antiviral therapy in CHB patients. The CYP27B1 gene, encoding 25(OH)D₃ -1α hydroxylase, might activate 25(OH)D₃ to 1,25(OH)₂ D₃ in kidney resulted in influencing the efficacy of interferon (IFN). The aim of the study was to investigate the association between CYP27B1 polymorphisms and the response to IFN in HBeAg-positive patients.

METHODS

Eighty-seven HBeAg-positive CHB patients infected with HBV genotype B or C were included in the study. All patients were treated with IFN at least 1 year. According to the response to PEG-IFN therapy, they were divided into three groups: 16 complete responses (CR), 42 partial responses (PR), and 29 nonresponses (NR). Sanger-sequencing was utilized to genotype the CYP27B1 SNPs(rs4646536 and rs10877012).

RESULTS

In logistic regression analysis, the frequency of rs4646536 CC genotype was observed to be higher in the NR group. Besides, the GG genotype of rs10877012 differed significantly among the three groups. The GG genotype was prevalent in patients with CR, and patients with TT genotype result in NR at the end of IFN treatment. The most common haplotype TG was independently associated with CR, after adjustment, and haplotype CT appeared to be associated with NR and PR, rather than CR. The data also showed that patients with baseline 1,25(OH)₂ D₃ > 39.39 pg/mL had higher CR rates at the end of IFN therapy.

CONCLUSION

These results suggested CYP28B1 gene polymorphisms may be independently associated with the efficacy of IFN in HBeAg-positive patients.

Hepatitis B in Egypt: A cross-sectional analysis of prevalence and risk factors for active infection from a nationwide survey

BACKGROUND & AIMS

Viral hepatitis is a major public health challenge in Egypt but little is known about the epidemiology of the hepatitis B virus (HBV) infection, its geographical distribution, or risk factors for infection in the Egyptian context. This study addresses this deficit using data from a nationally representative survey.

METHODS

Cross-sectional analysis of data gathered from men and women aged 15-59 in the Egypt Health Issues Survey (EHIS) 2015, including logistic regression to evaluate the contribution of different factors to risk of HBV infection. This was supplemented by spatial analysis of the distribution of acute or chronic HBV infection at governorate level, and the ecological relationship between HBV and HCV infections.

RESULTS

Population HBV prevalence was 1.4% (95% confidence interval [CI] 1.2-1.6), with a HBV-HCV co-infection rate of 0.06%. Spatial analysis showed localisation of HBV infected individuals primarily to urban areas of Upper Egypt (in contrast to HCV for which prevalence is highest in rural Lower Egypt), and those in early middle age (Adjusted Odds Ratio [AOR] 3.32, 95% CI: 1.66-6.63). HBV positive status among other household members emerged as a powerful driver of infection risk in this analysis (AOR=10.75, 95% CI: 4.98-23.24).

CONCLUSION

Spatial distribution of HBV infection in Egypt differs markedly from HCV and co-infection rates are low. Within-household transmissions appear to be particularly important in explaining the persistence of HBV infection in the general population. Prevention strategies should focus on urban Upper Egypt, and particularly those households with documented cases of infection.

Characteristics of escape mutations from occult hepatitis B virus infected patients with hematological malignancies in South Egypt

AIM

To investigate the prevalence and virological characteristics of occult hepatitis B virus (HBV) infections in patients with hematological malignancies in South Egypt.

METHODS

Serum samples were collected from 165 patients with hematological malignancies to monitor titers of HBV DNA, hepatitis B surface antigen (HBsAg), and antibodies to HBV core (anti-HBc) and surface antigens. Serum samples negative for HBsAg and positive for anti-HBc were subjected to nucleic acid extraction and HBV DNA detection by real-time polymerase chain reaction. DNA sequences spanning the S region were analyzed in cases with occult HBV infection. In vitro comparative study of constructed 1.24-fold wild type and S protein mutant HBV genotype D clones was further performed.

RESULTS

HBV DNA was detected in 23 (42.6%) of 54 patients with hematological malignancies who were HBsAg negative, but anti-HBc positive, suggesting the presence of occult HBV infection. The complete HBV genome was retrieved from 6 occult HBV patients, and P120T and S143L were detected in 3 and 2 cases, respectively. Site directed mutagenesis was done to produce 1.24-fold genotype D clones with amino acid mutations T120 and L143. The in vitro analyses revealed that a lower level of extracellular HBsAg was detected by chemiluminescence enzyme immunoassay (CLEIA) with the clone containing T120 mutation, compared with the wild type or the clone with S143L mutation despite the similar levels of extracellular and intracellular HBsAg detected by Western blot. Southern blot experiments showed that the levels of intracellular HBV DNA were not different between these clones.

CONCLUSION

Occult HBV infection is common in patients with hematological malignancies and associated with P120T and S143L mutations. 120T mutation impairs the detection of HBsAg by CLEIA.