Hepatitis B Surface Antigen Titers Research Articles

B-099 Development and Improvement of Novel MASTM Infectious Controls for Serology Diagnostic Tests

Abstract Background Human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) remain major infections around the world. As not all viral infections are preventable, serological assays play a critical role in diagnoses, therapeutic monitoring, and treatment of these infections. The Thermo Scientific™ MAS™ Omni™ Infectious Controls are a family of controls containing single or multiple analytes in human plasma-based matrix designed to mimic patient samples in the assessment of serological assay performance. One of the greatest challenges within the field of Infectious Serology testing is method variation amongst the semi-quantitative assays. As an example, a result that is considered a low positive on one analyzer, may be considered a high positive on a different analyzer. Therefore, platform agnostic Quality Control material will provide evaluation among different methods. Quality Controls may also be developed to focus on certain platforms based on “fit-for-purpose” applications. We report here the development and performance evaluation of the MAS™ Omni Infectious Controls - For Use with Siemens Assays. Methods Two new MAS™ Omni Infectious Controls were developed and characterized to be added to the existing catalog of MAS™ Omni Infectious Control Products. MAS™ Omni Infectious BSI (Bloodstream Infectious) Positive Control Panel—For Use with Siemens Assays* is a multi-constituent IVD quality control containing anti-HIV-1/2, anti-HBc, anti-HCV, and anti-HTLV I/II antibodies, as well as Hepatitis B surface antigen (HBsAg) that was developed for the Siemens Assays platform. The new product has been adapted from the existing BSI Positive Control Panel* by increasing the titer of HBsAg while decreasing the titer of anti-HBc and anti-HCV. MAS™ anti-HBs Positive Control - For Use with Siemens Assays* was developed for the assessment of assay performance detecting anti-HBs on the Siemens Assays Platform. The new product has been adapted from the existing anti-HBs Positive Control by increasing the titer of anti-HBs. Development and performance evaluations were performed on SIEMENS™ and non- SIEMENS™ platforms. Shelf life of the products are determined by accelerated, real-time stability, open vial, and in-use monitoring. Results Two new MAS™ Omni Infectious Controls were developed and evaluated to be specifically used on the Siemens Assays Platform. Both products demonstrated acceptable performance on the SIEMENS™ Centaur™ and Abbott™ Architect™. Stability studies demonstrated a minimum of 24- or 12-months shelf life, 30 or 60 days of open vial stability, and 8 hours of in-use stability when stored at 2–8°C, respectively. Additionally, the studies demonstrate a basic understanding of method variation within Infectious Serology test methods. Conclusions Two new MAS™ Omni Infectious Control products that mimic patient samples have been developed for the assessment of assay performance on the Siemens Assay Platform in the clinical laboratory for anti-HBc, anti-HCV, and Hepatitis B surface antigen (HBsAg). These reliable and stable control materials will better support the assessment of serological assay performance on the Siemens platforms. *Availability of product in each country depends on local regulatory marketing authorization status

Unraveling the Complexity of Atypical Serological Profiles in Chronic Hepatitis B: Insights Into Disease Dynamics and Clinical Implications.

Introduction Chronic hepatitis B (CHB) continues to be a significant global public health problem. Conventional serological markers play a pivotal role in diagnosing and prognosticating CHB, but atypical serological profiles deviating from established norms pose challenges. Methods A cohort of 35 CHB patients who did not receive an antiviral treatment with atypical serological markers was followed for five years (2017-2022). Demographics, serological parameters, and changes were documented. Serological parameters and serum viral loads (hepatitis B virus (HBV)-deoxyribonucleic acid (DNA) levels) were assayed at the central laboratory during their routine follow-ups. Three groups of atypical serological markers are defined: hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (anti-HBs) positivity; hepatitis B e antigen(HBeAg) and anti-hepatitis B e-antigen (anti-HBe) positivity; and isolated core (anti-hepatitis B core (anti-HBc) immunoglobulin G (IgG)) positivity. Patients with concomitant HBsAg and anti-HBs were also stratified into seroreversion groups. Changes in serological markers and HBV-DNA levels across the study period were documented and evaluated at the end of the study period. Statistical analysis was conducted using the Kruskal-Wallis test and IBM SPSS Statistics software for Windows, Version 23.0 (IBM Corp., Armonk, NY, USA). Results In a cohort of 35 patients with atypical hepatitis B serology, demographic analysis revealed that 51.4% (n=18) were female and 48.6% (n=17) were male, with a mean age of 45.7 years. Educational distribution showed that 45.7% (n=16) completed primary education, 22.8% (n=8) had a high school education, and 31.5% (n=11) held university degrees. Among these patients, 10 displayed the concurrent presence of HBsAg and anti-HBs, with 60% (n=6) being female. Serum HBV-DNA was detectable in all cases. After five years, 60% (n=6) exhibited seroconversion from HBsAg to anti-HBs, particularly notable in females (66.7%). These patients showed lower HBsAg titers and serum HBV-DNA levels (p = 0.048, p = 0.036). A subset of 15 patients demonstrated simultaneous HBeAg and anti-HBe positivity. The HBeAg seropositivity waned over time, with 40% (n=6) and 26.7% (n=4) females and males, respectively, retaining positivity by the fifth year. During this period, serum HBV-DNA levels decreased. The remaining five patients sustained HBeAg and anti-HBe positivity. Among 10 patients solely positive for anti-HBc IgG, three had concurrent HBV-DNA positivity. Strikingly, three patients with negative HBV-DNA developed anti-HBs positivity after five years. Conclusion The complexity of CHB infection demands a comprehensive understanding. Atypical serological profiles suggest distinct disease stages, immune response variations, and viral mutations. This study enhances comprehension of viral replication, immune responses, and disease progression, potentially guiding tailored therapeutic strategies.

An Insight Into the Factors Affecting the Prevalence and Natural History of Hepatitis D.

Epidemiological studies and recent metanalyses addressing hepatitis D have reported a wide variation in the prevalence of the disease. Between 4.5% to 15% of all hepatitis B surface antigen (HBsAg) positive patients are thought to harbor the hepatitis D virus. The emergent variation in prevalence can be attributed to several factors. Unsurprisingly, published literature shows that the prevalence of the disease is higher in areas where aggregate viral hepatitis infections are endemic and amongst groups with high-risk practices facilitating the horizontal transfer. Meanwhile, the natural history of the disease is influenced by the genotype of the virus, the hepatitis D virus (HDV) RNA levels, HBV-HDV codominance, HBsAg titers, HBV genotype, nutritional status, HIV co-infection, and prior treatment. Together these factors contribute to the accelerated development of fibrosis and the increased risk of hepatocellular carcinoma. Superinfection with genotype 1 results in rapid progression to cirrhosis with lower rates of remission. Genotype 3 follows an aggressive course but shows a good response to interferon therapy. Other genotypes have better outcomes. The course of the disease leading to these outcomes can be tracked by HDV-specific models integrating clinical surrogate markers and epidemiological factors such as age, region, alanine aminotransferase (ALT), gamma-glutamyl transferase, albumin, platelets and cholinesterase, and liver stiffness.

The Predictive Role of Hepatitis B Biomarkers on HBV Reactivation following Direct-Acting Antiviral Therapy in HBV/HCV Coinfected Patients.

Hepatitis B and C (HBV/HCV) coinfected patients have a potential risk of hepatitis B reactivation (HBVr) after direct-acting antivirals (DAAs) treatment. The study intends to investigate the predictive role of HBV biomarkers in HBVr. Forty-six HBV/HCV coinfected patients receiving DAAs were enrolled. All patients completed treatment and follow-up to the 12th-week post-DAA treatment (P12). Blood samples were measured for HBV biomarkers, including hepatitis B surface antigen (HBsAg), hepatitis B core-related antigen (HBcrAg), and HBV pregenomic RNA (HBV pgRNA). The predictive factors for HBVr after DAA treatment were analyzed. Among 31 patients without nucleot(s)ide analogue (NA) treatment, seven (22.5%, 7/31) developed HBVr without hepatitis flare-up. Patients with HBVr had higher HBsAg titers than those without HBVr from baseline to P12 (p = 0.008, 0.009, 0.004, and 0.006 at baseline, week 4, end of treatment, and P12, respectively). The baseline HBsAg level was the only predictive factor associated with HBVr (HR, 2.303; 95% CI, 1.086–4.882; p = 0.030). In predicting HBVr, a baseline HBsAg titer > 20 IU/mL had a sensitivity, specificity, positive predictive value, and negative predictive value of 85.7%, 75.0%, 50%, and 94.7%, respectively. No patient had HBVr if the baseline HBsAg titer was <8 IU/mL. Serum HBcrAg and HBV pgRNA levels had no role in predicting HBVr. In conclusion, HBV/HCV coinfected patients are at risk of HBVr after DAA treatment. The baseline HBsAg level was the predictive factor associated with HBVr. Patients with a baseline HBsAg titer < 8 IU/mL can be considered as not having HBVr.

Effect of switching from nucleos(t)ide maintenance therapy to PegIFN alfa-2a in patients with HBeAg-positive chronic hepatitis B: A randomized trial.

Induction of a durable viral response is difficult to achieve in patients with chronic hepatitis B (CHB), even from long-term use of a nucleos(t)ide analogue (NA). This study investigated whether switching to peginterferon (PegIFN) alfa-2a after long-term NA therapy induced a durable viral response. Patients with hepatitis B e antigen (HBeAg)-positive CHB who received any NA for at least 72 weeks and had a low level of HBV DNA (≤100 IU/mL) were randomized (1:1) to receive PegIFN alfa-2a (180 μg/week) or NA for 48 weeks. The primary endpoint was change in the hepatitis B surface antigen (HBsAg) titer during antiviral therapy. We randomized 149 CHB patients to the two groups. Compared to baseline, the HBsAg levels in both groups were not lower at week 12, but were lower after 24, 36, and 48 weeks (all p<0.001). The maximal HBsAg decline in the PegIFN alfa-2a group was at week 36 (0.50±0.88 log10 IU/mL), and this decline was smaller in the NA group (0.08±0.46 log10 IU/mL). The percentage of patients with HBeAg seroconversion at week 48 was also greater in the PegIFN alfa-2a group (15/75 [20.0%] vs. 5/74 [6.8%], p = 0.018). Multivariable analysis indicated the PegIFN alfa-2a group had a greater change in HBeAg seroconversion at week 48 (p = 0.027). Patients had relatively good tolerance to PegIFN alfa-2a therapy. CHB patients who switched to PegIFN alfa-2a for 48 weeks had a significantly lower HBsAg titer and increased HBeAg seroconversion relative to those who remained on NA therapy. (ClinicalTrials.gov; NCT01769833).

Correlation between Results of Semi-Quantitative and Quantitative Tests for Hepatitis B Virus Surface Antigen among Patients Achieving Viral Suppression with Antiviral Treatment.

Background: Hepatitis B virus (HBV) infection remains a threat to global public health. Serum hepatitis B surface antigen (HBsAg) has been used in screening for HBV infection. Quantitative HBsAg assays are useful for monitoring the natural history of HBV infection and its response to therapy. The aim of this study was to determine the relationship between quantitative (qHBsAg; IU/mL) and semi-quantitative (sqHBsAg; signal-to-cutoff ratio [S/Co]) HBsAg titers in patients with chronic hepatitis B (CHB). Methods: We retrospectively included 284 samples with HBV DNA < 20 IU/mL from patients who had simultaneous qHBsAg (using electrochemiluminescence assay) and sqHBsAg tests. Patients were grouped according to their serum HBV-envelope antigen (HBeAg) status (HBeAg-negative, n = 239 and HBeAg-positive, n = 45). The Spearman test was used to analyze the correlation between the quantitative and semi-quantitative assays. Results: There was a significant linear correlation between sqHBsAg and qHBsAg in the HBeAg-negative patients (qHBsAg [IU/mL] = 0.0094 × sqHBsAg [S/Co]1.323; adjusted R2 = 0.8445; p < 0.001). There was a substantial hook effect in the assays from the HBeAg-positive patients, so we performed a stratified analysis according to qHBsAg <1000 IU/mL or ≥1000 IU/mL and found a significant positive linear correlation between sqHBsAg S/Co and qHBsAg (qHBsAg [IU/mL] = 0.072 × sqHBsAg [S/Co]1.331; adjusted R2 = 0.7878; p < 0.001) in HBeAg-positive patients with qHBsAg titers of <1000 IU/mL and a significant negative correlation in HBeAg-positive patients with qHBsAg titers of ≥1000 IU/mL (qHBsAg [IU/mL] = 8.987 × 1014 × sqHBsAg [S/Co]−3.175; adjusted R2 = 0.6350; p < 0.001). Conclusions: There was a highly linear, positive correlation between qHBsAg and sqHBsAg in HBeAg-negative CHB patients. The hook effect led to a negative correlation in HBeAg-positive CHB patients with qHBsAg titers ≥1000 IU/mL.

The Impact of Sodium Dodecyl Sulfate and 2-Mercaptoethanol on Antibody and Antigen Binding.

To evaluate the effect of sodium dodecyl sulfate (SDS) and 2-mercaptoethanol (2-ME) on antigen-antibody binding when incubated at 100°C, which is the pretreatment temperature required for western blots. Serum that tested positive for hepatitis B surface antigen (HBsAg) plus loading buffer were mixed at a ratio of 4:1 and incubated in a water bath. We then detected HBsAg using double immunodiffusion and ELISA. The HBsAg titer was 1:512 in the control group when incubated at 37°C. Incubation with SDS at 100°C reduced the antigen titer to 1:32. The inhibitory effect on HBsAg titer reached 96.9% after incubation at 100°C with SDS and 2-ME. We detected strong inhibition of antigens in western blots via SDS and 2-ME. It is likely that false-negative results will be obtained from western blots of antigens with weak resistance to these reagents.

Thyroid dysfunction is associated with the loss of hepatitis B surface antigen in patients with chronic hepatitis B undergoing treatment with α-interferon.

ObjectiveTo investigate the influence of thyroid dysfunction on the antiviral efficacy of α-interferon in adult patients with chronic hepatitis B (CHB).MethodsWe performed a retrospective study of 342 patients with CHB who underwent interferon treatment for >12 weeks. Patients with thyroid dysfunction before or during treatment were defined as the thyroid dysfunction group (n = 141) and those with normal thyroid function were defined as the normal thyroid function group (n = 201). The prevalences of hepatitis B virus (HBV) DNA undetectability, low hepatitis B surface antigen (HBsAg) titre (<250 IU/mL), HBsAg loss, and hepatitis B envelope antigen loss were compared.ResultsDuring interferon treatment, 69 of 270 (25.6%) participants with normal thyroid function at baseline developed thyroid dysfunction, whereas 11 of 72 (15.3%) with thyroid dysfunction at baseline regained normal thyroid function. The thyroid dysfunction group had significantly higher prevalences of low HBsAg titre (29.8% vs. 18.9%) and HBV DNA undetectability (66.0% vs. 40.3%). Multivariate logistic regression analysis showed that thyroid dysfunction was associated with HBsAg loss (odds ratio 4.945, 95% confidence interval 1.325–18.462).ConclusionsThese results suggest that thyroid dysfunction is not an absolute contraindication, but is associated with HBsAg loss, in patients with CHB undergoing α-interferon treatment.

A perspective of the relationship of serum HBV DNA and HBsAg apportioned by the same hepatic parenchyma cell volume with inflammation in the natural history of chronic hepatitis B.

This study aimed to investigate the dynamic changes of serum HBV DNA and hepatitis B surface antigen (HBsAg) titers apportioned by the same hepatic parenchyma cell volume (HPCV) at different liver histological inflammation grades in the natural history of chronic hepatitis B (CHB). The serum HBV DNA and HBsAg titers were detected by real-time polymerase chain reaction and electrochemiluminescence, separately, in CHB patients without any treatment. The serum HBV DNA levels and HBsAg titers apportioned by the same HPCV were figured out based on sphere geometry theory. In addition, the differences of HBV DNA levels and HBsAg titers apportioned by the same HPCV in different liver inflammation grades were further assessed based on statistical analysis. There was no difference of serum HBV DNA levels or HBsAg titers before apportioned by the same HPCV in liver inflammation grades 1-4, but significant differences were observed after apportion in CHB patients (HBV DNA: P=0.101; HBsAg: P=0.211 & HBV DNA apportioned by HPCV: P<0.001; HBsAg apportioned by HPCV: P<0.001). No correlation was observed between HBV DNA levels and liver inflammation grades (r=0.083, P=0.186), or between HBsAg titers and liver inflammation grades (r=0.083, P=0.078). A significant correlation was observed between HBV DNA levels apportioned by HPCV and liver inflammation grades (r=0.249, P<0.001), and obvious correlation of HBsAg titers apportioned by HPCV and liver inflammation grades was also found in CHB patients (r=0.554, P<0.001). These results suggest that the levels of serum HBV DNA and HBsAg apportioned by the same HPCV are correlated with the severity of liver histological inflammation grade in the natural history of CHB.

The role of quantitative HBsAg in the natural history of e antigen-negative chronic hepatitis B: A Tunisian prospective study

Background/AimsDuring the natural course of Chronic Hepatitis B (CHB) infection, differentiation between inactive carrier (IC) and HBeAg negative CHB is a subject of ongoing debate. We studied the role of hepatitis B surface antigen (HBsAg) level as a means of differentiating between CHB and IC in a group of untreated chronic HBeAg-negative HBV-infected patients. StudyA total of 115 HBeAg negative carriers were enrolled and followed up for>12 months; 78 as inactive carriers (IC), and 37 as active carriers (AC). Among ACs, patients were categorized according to the highest rate of viral load: AC1 (n=23), active carriers with persistent HBV-DNA<20,000 IU/mL; AC2 (n=14), active carriers with HBV-DNA>20,000 IU/mL. ResultsHBsAg levels were higher in AC compared to IC patients (1607 IU/ml vs. 225 IU/ml respectively, P=0.001). Among the AC group, the 23 AC1 cases had HBsAg levels significantly lower than the 14 AC2 patients (1756 IU/mL vs. 3327 IU/mL respectively; P<10-3). HBsAg showed weak correlation with HBV-DNA in the whole cohort (r=0.44, P<0.01). The suggested cutoff value of HBsAg titer to differentiate between the two groups was 938 IU/mL. Combined single-point quantification of HBsAg (938 IU/mL) and HBV DNA (2000 IU/mL) identified IC with 87.2% specificity and 91.7% positive predictive value. ConclusionThis study confirms the predictability of a one-time combined HBsAg and HBV DNA measurement for true inactive carriers requiring neither strict follow-up nor antiviral treatment.

Field performance of HBsAg rapid diagnostic tests in rural Ethiopia

Point-of-care rapid diagnostic tests (POC-RDTs) are widely used to screen and diagnose hepatitis B virus (HBV) infection and are often the only available diagnostic tools in resource-limited settings. The aim of this study was to evaluate the validity of three hepatitis B surface antigen (HBsAg) POC-RDTs (Healgen®, Advanced Quality™ and Determine™) in an area with high prevalence of HBV in eastern Ethiopia. Results were compared with a commercial enzyme linked immunosorbent assay (ELISA) as gold standard. Quantification of HBsAg was performed in false negative samples.A total of 511 subjects were screened, of whom 81 (15.9 %) were HBsAg-positive with the gold standard. All three POC-RDTs were positive in 65 of the 81 positive samples, yielding a sensitivity (95 % confidence interval) of 80.2 % (70.3−87.5) and a specificity of 99.8 % (98.7−100 for Healgen® and Determine™; 98.6−100 for Advanced Quality™). False negatives were observed in 16 patients associated with low levels of HBsAg (median 1.5 IU/mL). All three POC-RDTs had reasonably high sensitivity and excellent specificity, but false negative results were observed in patients with low titres of HBsAg. Thus, these POC-RDTs might be useful to identify patients in need of HBV treatment, but cannot be recommended as blood donor screening tests.

Apolipoprotein H drives hepatitis B surface antigen retention and endoplasmic reticulum stress during hepatitis B virus infection.

Apolipoprotein H (APOH), also known as beta2-glycoprotein I (beta2-GPI), is an acute phase protein in hepatitis B virus (HBV) infection and binds to hepatitis B surface antigen (HBsAg) with high-affinity. APOH expression is upregulated by HBV and the large surface protein (LHBs), but also elevated in HBV-related hepatoma cells. Previous studies show that intracellular retention of HBsAg induces endoplasmic reticulum (ER) stress, a key driver of hepatocyte damage during chronic liver injury, but the mechanisms are unclear. We hypothesize that APOH mediates HBV-induced ER stress through increased retention of HBsAg. VR-APOH-myc and VR-LHBs-flag plasmids were constructed by PCR using pcDNA3.1(-)-APOH or an HBV expression vector, respectively. APOH and ER stress markers were examined at protein and mRNA levels by Western Blot or RT-qPCR. HBsAg titer was assayed by ELISA. RNA-seq was performed to elucidate the transcriptional impact of APOH manipulation in HBV-producing cells (HepG2.2.15 cells). We found that HBV upregulates APOH expression in 293 T cells, and APOH overexpression subsequently inhibits secretion of HBsAg. Next, we show that LHBs overexpression in conjunction with APOH leads to ER stress in 293 T cells, as evidenced by production of the binding immunoglobulin protein (BiP) and C/EBP homologous protein (CHOP), as well as increased splicing of X-box binding protein 1 (XBP1). We further observed that loss of beta2-GPI reduced CHOP expression in HepG2.2.15 cells, while beta2-GPI overexpression enhanced CHOP production. The interaction of beta2-GPI and HBV initiates ER stress through driving intracellular retention of HBsAg and activates the UPR.

Serum HBV RNA Dynamic and Drug Withdrawal Predictor Value in Patients With Chronic HBV Infection on Long-term Nucleos(t)ide Analogue (NA) Therapy.

This study aimed to investigate the dynamic pattern of serum hepatitis B virus (HBV) RNA in chronic hepatitis B (CHB) patients on long-term nucleos(t)ide analogue (NA) therapy and evaluate predictor value of end-of-treatment (EOT) serum HBV RNA status on drug-withdrawal durability. We carried out a real-life cohort study of 326 CHB patients on NA treatment between February 12, 2016 and February 21, 2018. Thirty of these patients discontinued NA treatment after enrollment, and were included in 2-year off-therapy follow-up. Serum HBV RNA levels were determined using the RNA simultaneous amplification testing method. Both serum HBV RNA and DNA levels declined significantly in long-term antiviral progress. When the treatment duration was longer than 3 years, the undetectable rates of HBV RNA and DNA were 55.10% and 97.0%, respectively. The serum HBV RNA-negative rate was 39.5%. The cumulative 2-year off-therapy viral and clinical relapse rate was 40.56%; 95% confidence interval (95% CI), 21.51-59.61 and 31.31%; 95% CI, 11.32-51.29 in all patients, respectively. Patients with EOT hepatitis B surface antigen (HBsAg)≤1000 IU/mL plus HBV RNA negativity had a relatively lower cumulative 2-year off-therapy viral relapse rate (23.01%; 95% CI, 0.17-45.99). EOT HBsAg≤1000 IU/mL plus HBV RNA negativity showed obvious superiority for the EOT HBsAg≤1000 IU/mL single in drug withdrawal durability prediction, with better specificity (18.18% vs. 72.73%, P=0.03), and the positive predictive value and negative predictive value were 76.92% and 47.06%, respectively. In the long-term antiviral process, both serum HBV RNA and DNA levels declined significantly. EOT serum HBV RNA negativity was not an independent drug withdrawal marker, but can complement the HBsAg titer to monitor drug withdrawal in CHB patients on long-term NA therapy.

Hepatitis B Surface Antigen Levels Are Related to Spontaneous Hepatitis B Surface Antigen Seroconversion in Inactive Hepatitis B Carriers.

The cure for hepatitis B is defined as the hepatitis B surface antigen (HBsAg) seroclearance and/or seroconversion. Predictors of spontaneous seroconversion are not well described. The objective of this study is to identify predictors of spontaneous HBsAg seroconversion from community practice. We performed a matched analysis of patients who HBsAg seroconverted (cases) and patients who did not HBsAg seroconvert (control) in a 1:5 ratio according to date of clinic visit between 2014 and 2019 in a large community practice situated in Los Angeles area. Baseline laboratory and clinical data were collected. Univariate analysis and 2-sided t tests were performed, χ test for proportions, and logistic regression. We identified 14 cases and 70 controls. The mean (±SD) ages of the cases and controls were 53.6 (±12.2) and 49.5 (±13.1), respectively (P=0.45). Most patients were women, and all patients were of Asian descent. There were statistically significant mean (±SD) baseline differences between cases and controls in HBsAg titers (459.8±311.0 and 782.0±393.3 IU/mL, P=0.01) and alanine aminotransferase (ALT) values (17.6±4.4 and 25.1±16.7 IU/mL, P<0.01), respectively. Baseline hepatitis B virus DNA and other pertinent laboratory values did not differ between cases and controls. Eleven of 14 cases (79%) and 11 of 70 controls (16%) baseline HBsAg titers were <1000 IU/mL (P<0.01). The results of a logistic regression demonstrated that HBsAg titers and ALT values were predictor variables for HBsAg seroconversion (P=0.01 and <0.01, respectively). Spontaneous HBsAg seroclearance and seroconversion is an uncommon event in patients with chronic hepatitis B. The most important predictors of seroconversion are HBsAg titers<1000 IU/mL and low baseline ALT values.

Comparative study of μ‐stat methanol feeding control in fed‐batch fermentation of Pichia pastoris producing HBsAg: an open‐loop control versus recurrent artificial neural network‐based feedback control

AbstractBACKGROUNDIn recent decades, artificial neural network (ANN) has been shown to be a robust and promising tool in monitoring and controlling bioprocess systems. In a previous study, the authors designed a highly accurate and precise recurrent neural network (RNN) for predicting the biomass amount of recombinant Pichia pastoris Mut+ producing intracellular hepatitis B surface antigen (HBsAg) during fed‐batch methanol fermentation. In the current work, the aim was to compare the production efficiency of HBsAg between conventional predefined μ‐stat methanol feeding control (open‐loop control) – already established in large‐scale production – and methanol feeding based on a μ‐stat feedback control system using RNN. For this purpose, for each methanol feeding strategy, bench‐scale, fed‐batch fermentation processes were carried out twice.RESULTSAccording to the results, in contrast to the established μ‐stat predefined feeding strategy (open‐loop), the deviation of specific growth rate and biomass in μ‐stat feedback control based on RNN was negligible. Also, in the suggested methanol feeding control strategy, the HBsAg titer, specific productivity and yield between the performed fed‐batch fermentations – unlike the conventional method – were approximately identical, with average values of 110.8 μg mL−1, 1.52 μg g−1 dry biomass and 0.34 μg g−1 MeOH respectively.CONCLUSIONComparing the biomass growth pattern and HBsAg production efficiency with the conventional μ‐stat predefined feeding in open‐loop control, the new proposed feeding control system illustrated significantly high process efficiency. This reliable control system based on ANN can have many applications in the biopharmaceutical industry for the control of process key parameters as well as for enhancing process efficiency. © 2019 Society of Chemical Industry

Continuous fermentation of recombinant Pichia pastoris Mut+ producing HBsAg: Optimizing dilution rate and determining strain-specific parameters

There is a growing interest in the biopharmaceutical industry to enhance production efficiency via shifting batch to continuous manufacturing. In the previous study, we demonstrated that under identical operation condition, continuous fermentation of recombinant Pichia pastoris (P. pastoris) Mut+ producing intracellular hepatitis B surface antigen (HBsAg) has considerably higher efficiency compared to the conventional fed-batch process. In the current work, by examining various dilution rates, we further optimized the process efficiency, and also determined some strain-specific parameters. According to the results, continuous operation at the dilution rate of 0.015 1/h demonstrated the highest performance compared to other dilution rates of 0.009, 0.02, 0.25, 0.03 and 0.0417 1/h. In the optimum dilution rate, the average HBsAg titer, yield, specific and volumetric productivity were 283.9mgHBsAg/L, 0.71mgHBsAg/g MeOH, 0.0097mgHBsAg/g wet cell weight (WCW)/h and 4.26mgHBsAg/L/h, respectively. Compared to the continuous fermentation in the previous study, the volumetric and specific productivities were improved by the factors of 2.0 and 2.5, respectively. Following Herbert-Pirt linear relation between specific growth rate and methanol consumption rate, the obtained biomass yield and maintenance coefficient in the continuous fermentation were 1.22 (g WCW/g MeOH) and 0.008 (g MeOH/g WCW/h), respectively. The consistency in the process condition and efficiency without any genetic instability and contamination in the one-month operation- in each fermentation run- suggests that the studied recombinant strain could be one of the potential candidates for continuous biomanufacturing of hepatitis B vaccine.

Accurate and cost-effective prediction of HBsAg titer in industrial scale fermentation process of recombinant Pichia pastoris by using neural network based soft sensor.

In the current work, the attempt was made to apply best-fitted artificial neural network (ANN) architecture and the respective training process for predicting final titer of hepatitis B surface antigen (HBsAg), produced intracellularly by recombinant Pichia pastoris Mut+ in the commercial scale. For this purpose, in large-scale fed-batch fermentation, using methanol for HBsAg induction and cell growth, three parameters of average specific growth rate, biomass yield, and dry biomass concentration-in the definite integral form with respect to fermentation time-were selected as input vectors; the final concentration of HBsAg was selected for the ANN output. Used dataset consists of 38 runs from previous batches; feed-forward ANN 3:5:1 with training algorithm of backpropagation based on a Bayesian regularization was trained and tested with a high degree of accuracy. Implementing the verified ANN for predicting the HBsAg titer of the five new fermentation runs, excluded from the dataset, in the full-scale production, the coefficient of regression and root-mean-square error were found to be 0.969299 and 2.716774, respectively. These results suggest that this verified soft sensor could be an excellent alternative for the current relatively expensive and time-intensive analytical techniques such as enzyme-linked immunosorbent assay in the biopharmaceutical industry.

Traditional Chinese Medicine Syndrome Patterns and Their Association with Hepatitis B Surface Antigen Levels during the Natural History of Chronic Hepatitis B Virus Infection.

The aim of this study is to investigate traditional Chinese medicine syndrome (TCMS) patterns and their association with hepatitis B surface antigen (HBsAg) levels during the natural history of chronic hepatitis B virus infection (CHB). Patients were categorized according to the phase of CHB, as follows: immune tolerance (ITP); immune clearance (ICP); low or nonreplication (LRP); reactivation (RAP); hepatic cirrhosis (HC); and primary liver cancer (PLC). TCMS patterns were classified among the following types: spleen-kidney deficiency (SKD); liver-qi depression (LQD); damp-heat in liver-gallbladder (LGDH); liver-kidney deficiency (LKD); and blood stasis blocking collateral (BSBC). HBsAg levels and other serological indicators were quantified for all patients and their association with TCMS was statistically analyzed and determined. Two hundred and eighty-nine patients with CHB were included. During the natural history of CHB, TCMS patterns were statistically different among the different phases (P < 0.001). The most frequently occurring syndromes among the six progressive phases were SKD, LGDH, LKD, LGDH, BSBC, and LGDH, respectively. The predominant patterns in the inactive stage (ITP + LRP), active stage (ICP + RAP), and late or advanced stage (HC + PLC) were SKD (31%), LGDH (51.8%) and BSBC (34.4%), respectively. Median HBsAg levels were also statistically different among the five patterns of TCMS (P < 0.001). The highest HBsAg levels were observed in SKD (4.48 log10 IU/mL). Medium levels were in LQD (3.91 log10 IU/mL) and LGDH (3.90 log10 IU/mL). The lowest HBsAg levels were in LKD (3.60 log10 IU/mL) and the second lowest levels in BSBC (3.81 log10 IU/mL). In addition, HBsAg levels in LKD and BSBC were significantly lower than those in SKD, LQD, and LGDH (P < 0.05 or 0.001). TCMS was altered during the natural history of CHB and correlated with HBsAg titers. This study could provide further insight into the therapy of CHB.

Entecavir add-on or switch-to pegylated interferon improves HBsAg clearance in HBe antigen negative chronic hepatitis B patients

Background and aimsChronic hepatitis B (CHB) patients rarely achieve hepatitis B surface antigen (HBsAg) loss with nucleoside/nucleotide analog therapy.MethodsIn this retrospective study, it was evaluated that the rate of HBsAg loss in the HBe antigen negative (HBeAg−) patients (n=101) treated with entecavir (ETV) for ≥24 weeks followed by switching to (n=22) or adding on (n=26) pegylated interferon (PEG-IFN), and continuing ETV (n=53).ResultsHBsAg clearance rate at week 48 was 9% (2/22), 15% (4/26), and 0% (0/53) (P<0.05), in switch-to or add-on, or ETV monotherapy CHB patients, respectively. HBsAg reduction at week 48 was 1.182, 0.6614, or 0.056 log IU/mL, in switch-to, add-on, and ETV patients, respectively (P<0.001). The response rate (HBsAg reduction >1 log IU/mL at week 48) in the switch-to, add-on, and ETV monotherapy CHB patients was 60%, 40%, and 2%, respectively (P<0.001). In the switch-to and add-on patients, HBsAg reduction and clearance were associated with HBsAg titers at week 0 and HBsAg reduction at week 24. Furthermore, HBsAg reduction at week 24 was associated with the response rate at week 48 in the switch-to and add-on patients, showing that the area under the receiver operating characteristic curve was 0.904. Positive predictive value and negative predictive value for response rate was 70% and 100% with cut-off value 0.2 log IU/mL, respectively.ConclusionIn summary, we demonstrated that PEG-IFN enhanced HBsAg loss in HBeAg− CHB patients. High HBsAg clearance was achieved in the patients with HBsAg titers at baseline <1,000 IU/mL and HBsAg reduction >0.2 log IU/mL.

Suppression of hepatitis B surface antigen production by combination therapy with nucleotide analogues and interferon in children with genotype C hepatitis B virus infection.

Sustained suppression of hepatitis B surface antigen (HBsAg) production after interferon (IFN) treatment has not been reported for children with genotype C chronic hepatitis B virus (HBV) infection, which is prevalent in Asia. Among children with hepatitis B envelope antigen-positive genotype C chronic HBV infection, we compared the efficacy of combination therapy with nucleotide analogues and IFN-α in 11 children with 12 historical cases treated with IFN monotherapy. The combination of lamivudine and conventional IFN-α was introduced for the first three patients; the other eight patients were treated with entecavir and pegylated IFN. Demographic factors as well as baseline HBsAg titers and HBV-DNA levels were similar between the two groups. In the combination therapy group, viral loads were suppressed in 9/11 to below 4.0logcopies/mL both at the end of the therapy (EOT) and at 6months after EOT. In contrast, in the IFN monotherapy group, suppression of viral loads was observed in 2/12 and 3/12 at EOT and at 6months after EOT, respectively. In the combination therapy group, HBsAg titers dropped from 4.03 at pretreatment to 2.91logIU/mL at 6months after EOT with 4/11 showing a drop to below 1000IU/mL (one patient achieved HBsAg clearance). In contrast, the amount of HBsAg did not change during the corresponding periods in the IFN monotherapy group. Our preliminary results suggest that combination therapy might be effective in the suppression of HBsAg production as well as HBV-DNA production for children with genotype C chronic HBV infection.