Hepatitis B Surface Antigen Quantification across Different Phases of Chronic Hepatitis B Virus Infection Using an Immunoradiometric Assay

Association of Hepatitis B Surface Antigen Levels With Long-Term Complications in Chronic Hepatitis B Virus Infection: A Systematic Literature Review

Chronic hepatitis B virus (HBV) infection is a global issue and can lead to cirrhosis and hepatocellular carcinoma (HCC). Hepatitis B surface antigen (HBsAg) is an important marker of HBV infection and HBsAg quantification could be a useful tool in clinical practice. This systematic literature review aimed to explore the association between HBsAg titres and long-term disease outcomes and evaluate the relationship between HBsAg titres, or changes in HBsAg titres, and clinical and treatment characteristics in patients with chronic HBV infection. Structured searches were performed in MEDLINE and Embase (January 2000 to 31 March 2023). Eighty-two studies were included, comprising 51% retrospective cohort studies, mostly conducted in Asia (85%). HBsAg levels were shown to predict the long-term development of cirrhosis and HCC in patients who were untreated prior to and during follow-up; however, these data were inconclusive in mixed and treated populations. HBsAg titres were significantly associated with various virological markers including serum HBV DNA, HBcrAg, HBeAg, HBV RNA levels, intrahepatic covalently closed circular DNA (cccDNA) and intrahepatic HBsAg expression. HBsAg titres generally declined over time; this decline was more pronounced in early (HBeAg-positive) than later disease phases (HBeAg-negative). Higher decline in HBsAg levels was consistently associated with subsequent HBsAg seroclearance and a greater decline in total intrahepatic HBV DNA and cccDNA levels. In conclusion, this review showed that HBsAg levels and rates of decline could inform assessment, management and prediction of outcomes in chronic HBV infection. Further studies in broader, more diverse populations and treated patients are needed.

Nanobiosensing based on optically selected antibodies and superparamagnetic labels for rapid and highly sensitive quantification of polyvalent hepatitis B surface antigen

Hepatitis B surface antigen (HBsAg) is the most clinically relevant serological marker of hepatitis B virus (HBV) infection. Its detection in blood is extremely important for identification of asymptomatic individuals or chronic HBV carriers, screening blood donors, and early seroconversion. Rapid point-of-care HBsAg tests are predominantly qualitative, and their analytical sensitivity does not meet the requirements of regulatory agencies. We present a highly sensitive lateral flow assay based on superparamagnetic nanoparticles for rapid quantification (within 30 min) of polyvalent HBsAg in serum. The demonstrated limit of detection (LOD) of 80 pg mL^-1 in human serum is better than both the FDA recommendations for HBsAg assays (which is 0.5 ng mL^-1) and the sensitivity of traditional laboratory-based methods such as enzyme linked immunosorbent assays. Along with the attractive LOD at lower concentrations and the wide linear dynamic range of more than 2.5 orders, the assay features rapidity, user-friendliness, on-site operation and effective performance in the complex biological medium. These are due to the combination of the immunochromatographic approach with a highly sensitive electronic registration of superparamagnetic nanolabels over the entire volume of a 3D test structure by their non-linear magnetization and selection of optimal antibodies by original optical label-free methods. The developed cost-efficient bioanalytical technology can be used in many socially important fields such as out-of-lab screening and diagnosis of HBV infection at a point-of-demand, especially in hard-to-reach or sparsely populated areas, as well as highly endemic regions.

Model for liver hardness using two-dimensional shear wave elastography, durometer, and preoperative biomarkers

BACKGROUND

Post-hepatectomy liver failure (PHLF) increases morbidity and mortality after liver resection for patients with advanced liver fibrosis and cirrhosis. Preoperative liver stiffness using two-dimensional shear wave elastography (2D-SWE) is widely used to evaluate the degree of fibrosis. However, the 2D-SWE results were not accurate. A durometer measures hardness by quantifying the ability of a material to locally resist the intrusion of hard objects into its surface. However, the durometer score can only be obtained during surgery.

AIM

To measure correlations among 2D-SWE, palpation by surgeons, and durometer-measured objective liver hardness and to construct a liver hardness regression model.

METHODS

We enrolled 74 hepatectomy patients with liver hardness in a derivation cohort. Tactile-based liver hardness scores (0-100) were determined through palpation of the liver tissue by surgeons. Additionally, liver hardness was measured using a durometer. Correlation coefficients for durometer-measured hardness and preoperative parameters were calculated. Multiple linear regression models were constructed to select the best predictive durometer scale. Receiver operating characteristic (ROC) curves and univariate and multivariate analyses were used to calculate the best model’s prediction of PHLF and risk factors for PHLF, respectively. A separate validation cohort (n = 162) was used to evaluate the model.

RESULTS

The stiffness measured using 2D-SWE and palpation scale had good linear correlation with durometer-measured hardness (Pearson rank correlation coefficient 0.704 and 0.729, respectively, P < 0.001). The best model for the durometer scale (hardness scale model) was based on stiffness, hepatitis B virus surface antigen, and albumin level and had an R² value of 0.580. The area under the ROC for the durometer and hardness scale for PHLF prediction were 0.807 (P = 0.002) and 0.785 (P = 0.005), respectively. The optimal cutoff value of the durometer and hardness scale was 27.38 (sensitivity = 0.900, specificity = 0.660) and 27.87 (sensitivity = 0.700, specificity = 0.787), respectively. Patients with a hardness scale score of > 27.87 were at a significantly higher risk of PHLF with hazard ratios of 7.835 (P = 0.015). The model’s PHLF predictive ability was confirmed in the validation cohort.

CONCLUSION

Liver stiffness assessed by 2D-SWE and palpation correlated well with durometer hardness values. The multiple linear regression model predicted durometer hardness values and PHLF.

Designing a magnetic inductive micro-electrode for virus monitoring: modelling and feasibility for hepatitis B virus

A simple model is designed for an inductive immunosensor in which the magnetic particles are attached to the bioreceptors to form a sandwich on the surface of an inductor. The inductor consists of a coil covered on a silicon oxide wafer. The coil comprises 250 turns of a planar gold wire, which is approximately 200 nm thick and 392 mm long, placed in a circle with a diameter of 2 mm. The model is well characterised by controlling the geometrical and electrical parameters and also the permeability of the magnetic material. To evaluate the feasibility of the model for virus monitoring, a novel inductive immunosensor is designed and for the first time applied for the detection of hepatitis B surface antigen (HBsAg). At first, Fab' segment of primary anti-HBsAg is immobilised on the coil. Then, the coil is exposed to HBsAg and the complex is introduced to a secondary antibody conjugated with magnetic particles to form an immune-sandwich. Finally, the influence of magnetic particles on the coil inductance is recorded and used as a signal for HBsAg detection. The magnetic inductive immunosensor showed specific responses toward HBsAg with the detection limit of 1 ng mL^-1, linear range of 1 to 200 ng mL^-1, and a sensitivity of 6 × 10^-4 mL ng^-1. The experimental results showed a very good agreement with simulation data indicating the compatibility of sensor sensitivity to the expected theoretical values. Graphical abstract.