Structural implications of amyloidogenic rare variants Ser282Leu and Gln356Arg identified in h-BRCA1.

Preliminary studies have shown BRCA1 (170-1600) residues to be intrinsically disordered with unknown structural details. However, thousands of clinically reported variants have been identified in this central region of BRCA1. Therefore, we aimed to characterize h-BRCA1(260-553) to assess the structural basis for pathogenicity of two rare missense variants Ser282Leu, Gln356Arg identified from the Indian and Russian populations respectively. Small-angle X-ray scattering analysis revealed WT scores Rg -32 Å, Dmax -93 Å, and Rflex-51% which are partially disordered, whereas Ser282Leu variant displayed a higher degree of disorderedness and Gln356Arg was observed to be aggregated. WT protein also possesses an inherent propensity to undergo a disorder-to-order transition in the presence of cruciform DNA and 2,2,2-Trifluoroethanol (TFE). An increased alpha-helical pattern was observed with increasing concentration of TFE for the Gln356Arg mutant whereas Ser282Leu mutant showed significant differences only at the highest TFE concentration. Furthermore, higher thermal shift was observed for WT-DNA complex compared to the Gln356Arg and Ser282Leu protein-DNA complex. Moreover, mature amyloid-like fibrils were observed with 30 µM thioflavin T (ThT) at 37°C for Ser282Leu and Gln356Arg proteins while the WT protein exists in a protofibril state as observed by TEM. Gln356Arg formed higher-order aggregates with amyloidogenesis over time as monitored by ThT fluorescence. In addition, computational analyses confirmed larger conformational fluctuations for Ser282Leu and Gln356Arg mutants than for the WT. The global structural alterations caused by these variants provide a mechanistic approach for further classification of the variants of uncertain clinical significance in BRCA1 into amyloidogenic variants which may have a significant role in disease pathogenesis.

Major HBV splice variant encoding a novel protein important for infection.

BACKGROUND & AIMS: HBV expresses more than 10 spliced RNAs from the viral pregenomic RNA, but their functions remain elusive and controversial. To address the function of HBV spliced RNAs, we generated splicing-deficient HBV mutants and conducted experiments to assess the impact of these mutants on HBV infection. METHODS: HepG2-NTCP cells, human hepatocyte chimeric FRG mice (hu-FRG mice), and serum from patients with chronic hepatitis B were used for experiments on HBV infection. Additionally, SHifter assays and cryo-electron microscopy were performed. RESULTS: We found the infectivity of splicing-deficient HBV was decreased 100-1,000-fold compared with that of wild-type HBV in hu-FRG mice. Another mutant, A487C, which loses the most abundant spliced RNA (SP1), also exhibits severely impaired infectivity. SP1 hypothetically encodes a novel protein HBcSP1 (HBc-Cys) that lacks the C-terminal cysteine from full-length HBc. In the SHifter assay, HBcSP1 was detected in wild-type viral particles at a ratio of about 20-100% vs. conventional HBc, as well as in the serum of patients with chronic hepatitis B, but not in A487C particles. When infection was conducted with a shorter incubation time of 4-8 h at lower PEG concentrations in HepG2-NTCP cells, the entry of the A487C mutant was significantly slower. SP1 cDNA complementation of the A487C mutant succeeded in rescuing its infectivity in hu-FRG mice and HepG2-NTCP cells. Moreover, cryo-electron microscopy revealed a disulfide bond between HBc cysteine 183 and 48 in the HBc intradimer of the A487C capsid, leading to a locked conformation that disfavored viral entry in contrast to the wild-type capsid. CONCLUSIONS: Prior studies unveiled the potential integration of the HBc-Cys protein into the HBV capsid. We confirmed the proposal and validated its identity and function during infection. IMPACT AND IMPLICATIONS: HBV SP1 RNA encodes a novel HBc protein (HBcSP1) that lacks the C-terminal cysteine from conventional HBc (HBc-Cys). HBcSP1 was detected in cell culture-derived HBV and confirmed in patients with chronic infection by both immunological and chemical modification assays at 10-50% of capsid. The splicing-deficient mutant HBV (A487C) impaired infectivity in human hepatocyte chimeric mice and viral entry in the HepG2-NTCP cell line. Furthermore, these deficiencies of the splicing-deficient mutant could be rescued by complementation with the SP1-encoded protein HBcSP1. We confirmed and validated the identity and function of HBcSP1 during infection, building on the current model of HBV particles.

Seeing haemoglobin SC: Challenging the misperceptions.

Historically understudied and regarded as a mild type of sickle cell disease, HbSC can be associated with significant, progressive complications. Prospective studies are urgently needed to address treatment gaps for HbSC disease. Commentary on: Nelson et al. The clinical spectrum of HbSC sickle cell disease-not a benign condition. Br J Haematol 2024;205:653-663.

Incidences of new hepatitis B infection and anti-hepatitis B core-negative occult hepatitis B infection among Japanese blood donors in relation to anti-hepatitis B surface antigen levels.

A transfusion-transmitted hepatitis B virus (HBV) infection caused by blood only positive for anti-hepatitis B surface antigen (anti-HBs) was reported. Occult HBV infection (OBI) with sole anti-HBs among blood donors is an issue. The incidence of HBV infection among repeat blood donors was investigated with a detailed HBV infection phase, focusing on the influence of anti-HBs level. This study followed 3 435 653 donors for HBV DNA conversion over 4 years and 9 months. Infection phase was determined based on marker changes over DNA conversion. This study identified 115 hepatitis B surface antigen (HBsAg) conversions, 72 DNA-only conversions, and 15 DNA plus anti-hepatitis B core (anti-HBc) conversions among donors all negative for HBV DNA, HBsAg, and anti-HBc. Total incidence was 2.38/100 000 person-years (PY). None of these 202 new HBV infections arose in the group with anti-HBs titer ≥ 10 mIU/mL. In total, 30 anti-HBc-negative OBIs were identified (incidence; 0.35/100 000 PY); 7 showed typical secondary anti-HBs response, and 23 showed stable anti-HBc and anti-HBs levels at DNA conversion. The HBV infection-protective ability of anti-HBs ≥ 10 mIU/mL was reinforced. In addition to new infections, the blood donor population includes anti-HBc-positive- and negative OBI with immune reactions or abortive HBV infection.

Significance of hepatitis B virus capsid dephosphorylation via polymerase.

BACKGROUND: It is generally believed that hepatitis B virus (HBV) core protein (HBc) dephosphorylation (de-P) is important for viral DNA synthesis and virion secretion. HBV polymerase contains four domains for terminal protein, spacer, reverse transcriptase, and RNase H activities. METHODS: HBV Polymerase mutants were transfected into HuH-7 cells and assayed for replication and HBc de-P by the Phos-tag gel analysis. Infection assay was performed by using a HepG2-NTCP-AS2 cell line. RESULTS: Here, we show that a novel phosphatase activity responsible for HBc de-P can be mapped to the C-terminal domain of the polymerase overlapping with the RNase H domain. Surprisingly, while HBc de-P is crucial for viral infectivity, it is essential for neither viral DNA synthesis nor virion secretion. The potential origin, significance, and mechanism of this polymerase-associated phosphatase activity are discussed in the context of an electrostatic homeostasis model. The Phos-tag gel analysis revealed an intriguing pattern of "bipolar distribution" of phosphorylated HBc and a de-P HBc doublet. CONCLUSIONS: It remains unknown if such a polymerase-associated phosphatase activity can be found in other related biosystems. This polymerase-associated phosphatase activity could be a druggable target in clinical therapy for hepatitis B.

International review of blood donation screening for anti-HBc and occult hepatitis B virus infection.

BACKGROUND: Hepatitis B core antibody (anti-HBc) screening has been implemented in many blood establishments to help prevent transmission of hepatitis B virus (HBV), including from donors with occult HBV infection (OBI). We review HBV screening algorithms across blood establishments globally and their potential effectiveness in reducing transmission risk. MATERIALS AND METHODS: A questionnaire on HBV screening and follow-up strategies was distributed to members of the International Society of Blood Transfusion working party on transfusion-transmitted infectious diseases. Screening data from 2022 were assimilated and analyzed. RESULTS: A total of 30 unique responses were received from 25 countries. Sixteen respondents screened all donations for anti-HBc, with 14 also screening all donations for HBV DNA. Anti-HBc prevalence was 0.42% in all blood donors and 1.19% in new donors in low-endemic countries; however, only 44% of respondents performed additional anti-HBc testing to exclude false reactivity. 0.68% of anti-HBc positive, HBsAg-negative donors had detectable HBV DNA. Ten respondents did universal HBV DNA screening without anti-HBc, whereas four respondents did not screen for either. Deferral strategies for anti-HBc positive donors were highly variable. One transfusion-transmission from an anti-HBc negative donor was reported. DISCUSSION: Anti-HBc screening identifies donors with OBI but also results in the unnecessary deferral of a significant number of donors with resolved HBV infection and donors with false-reactive anti-HBc results. Whilst confirmation of anti-HBc results could be improved to reduce donor deferral, transmission risks associated with anti-HBc negative OBI donors must be considered. In high-endemic areas, highly sensitive HBV DNA testing is required to identify infectious donors.

Blood donation screening for hepatitis B virus core antibodies: The importance of confirmatory testing and initial implication for rare blood donor groups.

BACKGROUND AND OBJECTIVES: Exclusion of blood donors with hepatitis B virus (HBV) core antibodies (anti-HBc) prevents transfusion-transmitted HBV infection but can lead to significant donor loss. As isolated anti-HBc positivity does not always indicate true past HBV infection, we have investigated the effectiveness of confirmatory anti-HBc testing and the representation of rare blood groups in anti-HBc-positive donors. MATERIALS AND METHODS: Three hundred ninety-seven HBV surface antigen-negative and anti-HBc initially reactive blood donor samples were tested by five different anti-HBc assays. RESULTS: Eighty percentage of samples reactive in Architect anti-HBc assay were positive by the Murex assay and anti-HBc neutralization. Eleven out of 397 samples showed discordant results in supplementary testing from the Murex confirmatory test result, and five remained undetermined following extensive serological testing. Thirty-eight percentage of anti-HBc-positive donors identified as minority ethnic groups compared with 11% representation in anti-HBc-negative donors (p < 0.0001); the frequency of the Ro blood group in anti-HBc-positive donors was 18 times higher in non-white ethnic groups. CONCLUSION: Using two anti-HBc assays effectively enabled the identification of HBV-exposed and potentially infectious donors, their deferral and potential clinical follow-up. However, the exclusion of confirmed anti-HBc-positive donors will still impact the supply of rare blood such as Ro.

Prevalence of occult hepatitis B virus infection and characterisation of hepatitis B surface antigen mutants among adults in western Croatia.

INTRODUCTION AND OBJECTIVES: Occult hepatitis B virus (HBV) infection (OBI) is characterised by low levels of hepatitis B virus (HBV) DNA in the blood/liver of patients with negative hepatitis B surface antigen (HBsAg). This study aimed to determine the OBI prevalence and virological characteristics (viral genotypes and HBsAg mutants) in patients with an "anti-HBc only" serological profile. MATERIALS AND METHODS: A total of 24 900 serum samples were routinely screened for hepatitis B markers over a five-year period. All anti-HBc-positive/HBsAg-negative/anti-HBs-negative sera were selected and analysed for the presence of HBV DNA. Mutational analyses of the HBs gene and polymerase gene sequences were performed. RESULTS: 1749 (7.02%) sera were anti-HBc positive, and 113 (0.45%) sera had an "anti-HBc only" serological profile (HBsAg/anti-HBs negative). HBV DNA was detected in 12/113 (10.61%) "anti-HBc only" positive sera, representing 0.048% of all routinely tested samples. Due to extremely low viremia, HBV genome was successfully sequenced in only two sera where subgenotype D3 was confirmed. Mutational analyses of the S gene revealed multiple missense mutations. In addition to the M133I, Y134F, and G145R mutations, already associated with diagnostic escape, we also found nine novel OBI-related S-gene mutations - S136Y, F158L, K160N, E164G, S167L, A168V, L175S, S210I and F212C. CONCLUSIONS: We detected multiple known and novel S gene mutations in 2/12 (16.6%) OBI cases, nevertheless, further studies are required to determine their role in the pathogenesis of OBI. Understanding the frequencies of clinically relevant HBV mutations may contribute to improvement of diagnostic protocols.

Assessment of biometeorological conditions in Eastern Mediterranean City Adana, Turkey from past to the future.

Human bioclimatic comfort (HBC) is an important subject of climatology in the field of physical geography. Human bioclimatic comfort (HBC) is the feeling of satisfied and comfortable within the ambient atmospheric thermal environment. Earth climate system has been exposed to changes from the beginning, but since 19th century human - induced factors have contributed to these changes. HBC is the combined effect of atmospheric conditions and affected by all the changes in them. Turkey is among the countries in Mediterranean region, expected to develop higher vulnerabilities to the (bio) climate hazards. Therefore, a Mediterranean city in the south of the country, Adana, was chosen as the study area. HBC assessment was made for the past (1961 - 1990), present (1991 - 2022), near (2030 - 2060) and distant future (2070 - 2100) using hourly - data from the official meteorology station between 1961 and 2022, daily data of the climate model scenarios (Representative Concentration Pathway - RCP4.5 and RCP8.5) and Physiological Equivalent Temperature (PET) index, the Rayman model and Geographic Information Systems in the spatial distribution of HBC conditions. The analysis showed that the prevalence of "cold" and "cool" stresses has decreased while that of "hot" and "very hot" stresses has increased from the past to the present in Adana. It is predicted that present conditions will continue in the near and distant future, all comfort ranges will increase to the following warm range and the ideal period for HBC conditions will be the winter season. In order to reduce the adverse HBC conditions in cities due to climate change by creating climate resilient, sustainable and healthy cities, urban design and planning principles should be followed from a geographical point of view.

Seroprevalence Study of Anti-HBs Antibodies in the General Population of Vojvodina, Serbia.

Background and Objectives: Hepatitis B (HB) is a major global health problem and a potentially life-threatening disease caused by the hepatitis B virus (HBV). Also, it is an important cause of morbidity and mortality worldwide. Thanks to serological surveys, testing hepatitis B surface antibodies (anti-HBs) allows for serological assessments of their prevalence. The presence of anti-HBs, which protects against HBV infection, can be attributed to HB vaccination or natural HBV infection. The aim of our study was to evaluate the prevalence of HB surface antibodies (anti-HBs) as an indicator of collective immunity against HBV in the general population of the Autonomous Province of Vojvodina, Serbia. In addition, to distinguish whether anti-HBs were induced by the vaccine or by infection, the presence of antibodies against the hepatitis B core antigen (anti-HBc) was tested among those who were anti-HBs-positive. Materials and Methods: A total of 3467 residual sera samples, collected according to the specifications of the European Sero-Epidemiology Network 2 (ESEN2) study, from April 2015 to March 2016, were screened for the presence of anti-HBs using a chemiluminescence immunoassay. The difference between categorical variables was tested using the chi-square test. Results: Overall, 1870 (53.9%, 95% CI: 52.3-55.6) participants tested positive for anti-HBs. The median age of the study participants was 17 years (IQR 9-35). The anti-HB seroprevalence decreased with age, ranging from 80.7% (95% CI: 78.9-82.4) in the 1-19-year-old group to 16.4% (95% CI: 12.0-20.9) in the ≥60 years' age group. A total of 71 (3.8%, 95% CI: 2.9-4.7) serum samples were also anti-HBc-positive. Higher prevalence, but not statistically significant, was noticed in women (4.1%, 95% CI: 2.8-5.4) compared with men (3.5, 95% CI: 2.4-4.8) (p = 0.542). Also, there was a significant difference across the age groups, where those ≥60 years old had a prevalence of 65.9% (95% CI: 51.9-79.9) and the age category of 1-19-year-olds had just 0.2% (95% CI: 0.0-0.4) (p < 0.001). Conclusions: This study provides a comprehensive assessment of the anti-HBs seroprevalence of the general population in Vojvodina and provides an opportunity to better shape the national preventive strategy related to HBV.

Ultrasensitive PCR system for HBV DNA detection: Risk stratification for occult hepatitis B virus infection in English blood donors.

Occult hepatitis B (HBV) infection (OBI), characterized by low viral loads, accounts for much of the risk of HBV transfusion-transmitted infection. With anticore antibodies (anti-HBc) screening introduced in England, the imperative to identify OBI donors has increased. We aimed to develop an ultra-sensitive PCR system and investigate risk factors for HBV DNA presence in blood donations. Seven extraction methods and three PCR assays were compared. The optimal system was sought to determine HBV DNA presence in anti-HBc-positive donations. Predictors of DNA positivity were subsequently investigated. Extraction from 5 mL of plasma increased sample representation and resulted in HBV DNA detection in low viral load samples (~0.5 IU/mL). Screening of 487 763 donations in 2022 identified two OBI donors and 2042 anti-HBc-positive donors, 412 of the latter with anti-HBs < 100 mIU/mL. Testing of 134 anti-HBc-positive donations utilizing the 5 mL extraction method identified two further HBV DNA-positive donations. Higher anti-HBc titer and anti-HBs negativity were significant predictors of DNA detectability in anti-HBc-positive donations. An ultrasensitive PCR assay identified potentially infectious donations increasing HBV DNA detection in anti-HBc-positive donors from 0.5% to 1.9%. Anti-HBc titers may further complement the risk stratification for DNA positivity in anti-HBc screening and minimize unnecessary donor deferral.

Transfusion-transmitted HBV infection with isolated anti-HBs-positive blood.

BACKGROUND: Hepatitis B virus (HBV)-positive individuals with isolated anti-HBs are found among HBV vaccine recipients and healthy blood donors with no vaccination history. HBV infectivity from blood transfusions derived from such individuals remains unclear. CASE PRESENTATION: A male patient who received transfusion with blood negative for individual donation-NAT, HBsAg and anti-HBc but weakly positive for anti-HBs developed typical transfusion-transmitted (TT)-HBV with anti-HBc response. The responsible blood donor was a frequent repeat donor showing a marked increase in anti-HBs titer without anti-HBc response 84 days after index donation. Test results for his past donations showed transient viremia with very low viral load and fluctuating low-level anti-HBs. The HBV vaccination history of this donor was unknown. DISCUSSION: Anti-HBs and anti-HBc kinetics of the donor suggest a second antibody response to new HBV challenge, representing a vaccine breakthrough case. On the other hand, transient low-level viremia and fluctuating anti-HBs in the test results of past donations suggested chronic occult HBV infection with isolated anti-HBs. CONCLUSION: Whatever the basic infection state, blood donors with isolated weak anti-HBs may include a small population with a risk of causing TT-HBV. Identifying individuals harboring such TT-HBV risk among individuals positive only for anti-HBs is difficult under current screening strategies. Active surveillance for the occurrence of TT-HBV with blood positive only for anti-HBs is necessary.

Chimeric Hepatitis B core virus-like particles harboring SARS-CoV2 epitope elicit a humoral immune response in mice.

BACKGROUND: Virus-like particles are an interesting vector platform for vaccine development. Particularly, Hepatitis B virus core antigen has been used as a promising VLP platform. It is highly expressed in different recombinant expression systems, such as E. coli, and self-assembled in vitro. It effectively improves the immunogenicity of foreign antigenic epitopes on its surface. Various foreign antigens from bacteria, viruses, and protozoa can be genetically inserted into such nanoparticles. The effective immunogenicity due to VLP vaccines has been reported. However, no research has been performed on the SARS-CoV2 vaccine within this unique platform through genetic engineering. Considering the high yield of target proteins, low cost of production, and feasibility of scaling up, E. coli is an outstanding expression platform to develop such vaccines. Therefore, in this investigation, we planned to study and develop a unique HBc VLP-based vaccine against SARS-Cov2 utilizing the E. coli expression system due to its importance. RESULTS: Insertion of the selected epitope was done into the major immunodominant region (MIR) of truncated (149 residues) hepatitis B core capsid protein. The chimeric protein was constructed in PET28a+ and expressed through the bacterial E. coli BL21 expression system. However, the protein was expressed in inclusion body forms and extracted following urea denaturation from the insoluble phase. Following the extraction, the vaccine protein was purified using Ni2 + iminodiacetic acid (IDA) affinity chromatography. SDS-PAGE and western blotting were used to confirm the protein expression. Regarding the denaturation step, the unavoidable refolding process was carried out, so that the chimeric VLP reassembled in native conformation. Based on the transmission electron microscopy (TEM) analysis, the HBC VLP was successfully assembled. Confirming the assembled chimeric VLP, we explored the immunogenic effectivity of the vaccine through mice immunization with two-dose vaccination with and without adjuvant. The utilization of adjuvant was suggested to assess the effect of adjuvant on improving the immune elicitation of chimeric VLP-based vaccine. Immunization analysis based on anti-spike specific IgG antibody showed a significant increase in antibody production in harvested serum from immunized mice with HBc-VLP harboring antigenic epitope compared to HBc-VLP- and PBS-injected mice. CONCLUSIONS: The results approved the successful production and the effectiveness of the vaccine in terms of humoral IgG antibody production. Therefore, this platform can be considered a promising strategy for developing safe and reasonable vaccines; however, more complementary immunological evaluations are needed.

Levels of Antibodies to Hepatitis B Core Antigen Are Associated With Liver Inflammation and Response to Peginterferon in Patients With Chronic Hepatitis B.

BACKGROUND: Emerging evidence suggests a pivotal role for B-cell responses in the natural history of chronic hepatitis B. Serum levels of antibodies to hepatitis B core antigen (anti-HBc) vary across infection stages, but their role in predicting response to antiviral therapy is uncertain. METHODS: Anti-HBc levels were assessed before peginterferon (PEG-IFN) therapy in patients with chronic hepatitis B who either started de novo PEG-IFN (n = 299; 195 hepatitis B e antigen [HBeAg] positive) or started PEG-IFN as add-on to an existing nucleo(s)tide analogue backbone (n = 91; all HBeAg-positive). Associations were explored between anti-HBc and (1) serum biomarkers, (2) liver histological findings, and (3) treatment response. RESULTS: We studied 390 patients. The hepatitis B virus (HBV) genotype were A, B, C, and D in 24%, 9%, 16%, and 49%, respectively; 72% of patients were Caucasian. Among currently untreated HBeAg-positive patients, anti-HBc was correlated with HBV DNA, hepatitis B core-related antigen (HBcrAg), hepatitis B surface antigen (HBsAg), and HBV RNA, but not with alanine aminotransferase (ALT). Higher anti-HBc was associated with more severe histological inflammatory activity (P < .001), irrespective of HBeAg status. After de novo PEG-IFN, higher anti-HBc levels were associated with HBeAg loss, sustained response, HBsAg decline, and HBsAg clearance (P < .050). Among patients treated with add-on PEG-IFN, higher anti-HBc was associated with HBeAg loss (P = .01). CONCLUSIONS: Serum anti-HBc levels correlate with histological inflammatory activity. Higher anti-HBc levels were associated with favorable treatment outcomes. These findings suggest that anti-HBc could be used to select patients most likely to respond to immunomodulatory therapy. CLINICAL TRIALS REGISTRATION: NCT00114361, NCT00146705, NCT00877760, and NCT01532843.

OCRELIZUMAB THERAPY IN PATIENTS WITH ANTI-HBC ANTIBODIES - A PRELIMINARY STUDY.

OBJECTIVE: Aim: Multiple sclerosis (MS) is a chronic inflammatory neurodegenerative disease resulting in cognitive impairment, physical disabilities, and neurological symptoms. Ocrelizumab is an effective drug used in MS treatment. However, it causes a risk of hepatitis B reactivation in anti-HBc positive patients. We describe the impact of entecavir and tenofovir on HBV reactivation during treatment with ocrelizumab. PATIENTS AND METHODS: Materials and methods: Our study included eight patients (aged 18-70 years) with positive anti-HBc antibodies who were diagnosed with MS based on the 2017 McDonald criteria. The subjects were treated with ocrelizumab and were given anti-HBV prophylaxis with nucleoside analogs. The mean time from the beginning of therapy with nucleoside analogs to the initiation of ocrelizumab treatment was 27.5 days. Patients were administered ocrelizumab and none of them was diagnosed with HBV reactivation. RESULTS: Results: None of the laboratory parameters worsened. No severe adverse effects were observed. These results suggest that entecavir and tenofovir are effective in HBV reactivation prophylaxis. Additionally, positive anti-HBc antibodies do not rule out treatment with ocrelizumab. CONCLUSION: Conclusions: In patients with positive anti-HBc antibodies, nucleoside analogs, such as entecavir or tenofovir, should be administered before ocrelizumab administration to reduce the risk of viral reactivation. Further studies on simultaneous treatment with ocrelizumab and nucleoside analogs are required to confirm our findings.

Significance of anti-HBc serological status in primary immune thrombocytopenia.

The association of previous hepatitis B virus (HBV) exposure [hepatitis B surface antigen (HBsAg) negative, hepatitis B core antibody (anti-HBc/HBcAb) positive] with disease severity and decision on treatment option in primary immune thrombocytopenia (ITP) patients remains unclear. Data from 725 patients diagnosed with ITP were analyzed to elucidate the association between anti-HBc serological status and disease severity. Data from a published prospective study [high-dose dexamethasone (HD-DXM), HD-DXM plus recombinant human thrombopoietin, NCT01734044] and two retrospective studies (standard-dose and low-dose rituximab) were rearranged to evaluate the impact of anti-HBc serological status on the response and outcome to ITP-specific treatments and the risk of HBV reactivation related to these treatments. The prevalence of HBsAg- HBcAb+ and HBsAg- HBcAb- in ITP patients was 51·03% and 48·97% respectively. Compared to the HBsAg- HBcAb- group, patients in the HBsAg- HBcAb+ group had lower platelet count, higher bleeding score, and longer hospitalization (P = 0·002, 0·033, and 0·008 respectively). Moreover, the initial complete response rate of HBsAg- HBcAb+ patients was lower than that of HBsAg- HBcAb- patients (45·2% vs 59·8%, P = 0·027). In conclusion, previous HBV exposure was correlated with disease severity and hospitalization in ITP patients. Anti-HBc positivity may be considered as a predictor for poor response to ITP-specific treatments.

Horizontal transmission might be a common route of hepatitis B virus exposure in highly endemic areas.

Hepatitis B virus (HBV) is a common viral pathogen that infects more than a third of the world's population; however, the transmission route remains to be further defined. The 18-year implementation of the free HBV vaccine for children has greatly changed the prevalence of HBV infection in China, which presents a unique real-world model for assessing the pattern of HBV transmission. Cross-sectional data of HBV seromarkers between July 2019 and April 2020 were collected from 53 371 individuals aged 1-60 years in four areas of North to South in Eastern China. Longitudinal data of HBV seromarkers between 2007 and 2020 were collected from 177 adults in an area of South China. The regional- and age-specific changes in HBV seromarkers were analyzed. Overall, positive rates of HBV surface antigen (HBsAg; from 3.44% to 15.1%) and antibody against HBV core antigen (anti-HBc; from 7.6% to 44.0%) significantly increased from North to South. Among persons aged ≤18 years, the positive rates of antibody against HBsAg (anti-HBs) and anti-HBc (+) remained at low levels in the North, while they were increasing among persons aged >12 years in the South, despite higher positive rates of anti-HBs (+). Among persons aged >18 years, the anti-HBs (+) rates remained relatively stable (~60%), while anti-HBc (+) rates increased significantly with age. Up to ~80% of the anti-HBs (+) adults in the South was anti-HBc (+) while it was 13.6% in the North. In the longitudinal cohort, the anti-HBc (+) rate among adults in the South increased by 14.2% during 10 years of follow-up. Horizontal transmission might be a common route in highly endemic areas, and may help to explain the high HBV exposure worldwide. The risk of horizontal transmission among children without seroprotective anti-HBs should be notified in highly endemic areas.

Hepatitis B virus virion secretion is a CRM1-spike-mediated late event.

BACKGROUND: Hepatitis B virus (HBV) is a major human pathogen worldwide. To date, there is no curative treatment for chronic hepatitis B. The mechanism of virion secretion remains to be investigated. Previously, we found that nuclear export of HBc particles can be facilitated via two CRM1-specific nuclear export signals (NES) at the spike tip. METHODS: In this study, we used site-directed mutagenesis at the CRM1 NES, as well as treatment with CRM1 inhibitors at a low concentration, or CRM1-specific shRNA knockdown, in HBV-producing cell culture, and measured the secretion of various HBV viral and subviral particles via a native agarose gel electrophoresis assay. Separated HBV particles were characterized by Western blot analysis, and their genomic DNA contents were measured by Southern blot analysis. Secreted extracellular particles were compared with intracellular HBc capsids for DNA synthesis and capsid formation. Virion secretion and the in vivo interactions among HBc capsids, CRM1 and microtubules, were examined by proximity ligation assay, immunofluorescence microscopy, and nocodazole treatment. RESULTS: We report here that the tip of spike of HBV core (HBc) particles (capsids) contains a complex sensor for secretion of both HBV virions and naked capsids. HBV virion secretion is closely associated with HBc nuclear export in a CRM1-dependent manner. At the conformationally flexible spike tips of HBc particles, NES motifs overlap extensively with motifs important for secretion of HBV virions and naked capsids. CONCLUSIONS: We provided experimental evidence that virions and naked capsids can egress via two distinct, yet overlapping, pathways. Unlike the secretion of naked capsids, HBV virion secretion is highly CRM1- and microtubule-dependent. CRM1 is well known for its involvement in nuclear transport in literature. To our knowledge, this is the first report that CRM1 is required for virion secretion. CRM1 inhibitors could be a promising therapeutic candidate for chronic HBV patients in clinical medicine.

Serum qAnti-HBc combined with ALT and HBsAg predicts significant hepatic inflammation in HBeAg-positive immune active patients.

BACKGROUND AND AIM: Quantitative hepatitis B core antibody (qAnti-HBc) level has been reported to predict significant liver inflammation in treatment-naïve chronic hepatitis B patients. However, little evidence has been revealed that qAnti-HBc alone or with other serum parameters in predicting moderate to severe hepatic inflammation in HBeAg-positive immune active patients treated with entecavir (ETV). METHODS: A total of 142 patients with HBeAg-positive immune active hepatitis were recruited in our study. Serum liver biochemistry, qAnti-HBc, hepatitis B virus markers, and liver inflammation were evaluated during 48-week ETV treatment. The association between liver inflammation grades and serum markers was systematically analyzed. RESULTS: The patients with moderate to severe inflammation (≥ G2) had a significantly higher level of qAnti-HBc compared with those with no to mild liver inflammation patients (< G2). The levels of qAnti-HBc and alanine transaminase (ALT) were positively correlated with hepatic inflammation grades, and qAnti-HBc had a better correlation than ALT, whereas HBsAg was negatively correlated with hepatic inflammation grades before treatment. After 48-week ETV treatment, no correlation was observed between hepatic inflammation grades and qAnti-HBc, ALT, or HBsAg. The combination of qAnti-HBc, ALT, and HBsAg had better performance in predicting significant liver inflammation (≥ G2) than qAnti-HBc alone or its combination with ALT. CONCLUSION: Serum qAnti-HBc levels were positively correlated with hepatic inflammation grades before treatment, but no positive correlation between them was observed after 48-week treatment. The level of qAnti-HBc combined with ALT and HBsAg may serve as a more reliable marker for identifying significant liver inflammation before treatment in HBeAg-positive immune active patients.

Prevalence and incidence rates of laboratory-confirmed hepatitis B infection in South Africa, 2015 to 2019.

BACKGROUND: Hepatitis B virus (HBV), a global public health threat, is targeted for elimination by 2030. As national HBV prevalence and incidence is lacking for South Africa, our study aimed to provide such data in the public health sector. METHODS: We analysed laboratory-confirmed HBV data from 2015 to 2019 to determine annual prevalence and incidence rates of HBV infection per 100,000 population, HBsAg and anti-HBc IgM test positivity rates, and HBsAg and anti-HBc IgM testing rates per 100,000 population. Time trend and statistical analyses were performed on HBsAg and anti-HBc IgM test positivity rates. RESULTS: The national prevalence rate of HBV infection per 100,000 population increased from 56.14 in 2015 to 67.76 in 2019. Over the five years, the prevalence rate was higher in males than females, highest amongst individuals 25 to 49 years old and highest in Gauteng province. The HBsAg test positivity rate dropped from 9.77% in 2015 to 8.09% in 2019. Over the five years, the HBsAg test positivity rate was higher in males than females, amongst individuals 25 to 49 years old and amongst individuals of Limpopo province. Amongst HBsAg positive children under 5 years old, the majority (65.7%) were less than a year old. HBsAg testing rates per 100,000 population were higher in females under 45 years of age and in males 45 years and above. The national incidence rate of acute HBV infection per 100,000 population dropped from 3.17 in 2015 to 1.69 in 2019. Over the five-year period, incidence rates were similar between males and females, highest amongst individuals 20 to 39 years old and highest in Mpumalanga province. Amongst individuals 20 to 24 years old, there was a substantial decline in the incidence and anti-HBc IgM test positivity rates over time. Anti-HBc IgM testing rates per 100,000 population were higher in females under 40 years of age and in males 40 years and above. CONCLUSION: Critical to hepatitis B elimination is strengthened infant vaccination coverage and interruption of vertical transmission. Transmission of HBV infection in adults may be reduced through heightened awareness of transmission routes and prevention measures.