Potential of ultra-highly sensitive immunoassays for hepatitis B surface and core-related antigens in patients with or without development of hepatocellular carcinoma after hepatitis B surface antigen seroclearance.

AIMS: Hepatitis B surface antigen (HBsAg) seroclearance indicates a "functional cure" in chronic hepatitis B (CHB) virus infection. However, several cases of hepatocellular carcinoma (HCC) development have been reported after HBsAg seroclearance. We evaluated the potential of HBsAg and hepatitis B core-related antigen (HBcrAg), measured by the ultra-highly sensitive assays, in cases with HCC development after HBsAg seroclearance. METHODS: We enrolled 17 patients with CHB who achieved HBsAg seroclearance, defined by the conventional assay using Architect HBsAg QT kit (five HCC patients and 12 non-HCC patients). HBsAg and HBcrAg were measured in their stored serum samples using ultra-highly sensitive assays featuring "immunoassay for total antigen including complex via pretreatment (iTACT)" technology. RESULTS: All five patients who developed HCC were positive for HBsAg or HBcrAg by iTACT-HBsAg or iTACT-HBcrAg at all follow-up points. HBcrAg levels in the HCC group, using iTACT-HBcrAg, were significantly higher than those in the non-HCC group at HBsAg seroclearance (3.6 LogU/ml (2.8-4.2) versus 2.6 (<2.1-3.8), p = 0.020). The best cutoff value of iTACT-HBcrAg for predicting HCC development was 2.7 LogU/ml by receiver operating characteristic curve analysis. The prevalence of HBcrAg ≥2.7 in the HCC group was significantly higher than that in non-HCC group (100% [5/5] versus 33% [4/12], p = 0.029). CONCLUSIONS: Residual low viral antigen might predict HCC development even if HBsAg seroclearance was achieved according to a conventional assay. The results suggest that iTACT assays of HBsAg and HBcrAg would be useful for monitoring CHB patients.

Hepatitis B Core-related Antigen: An Alternative to Hepatitis B Virus DNA to Assess Treatment Eligibility in Africa.

BACKGROUND: To eliminate hepatitis B virus (HBV) infection, it is essential to scale up testing and treatment. However, conventional tools to assess treatment eligibility, particularly nucleic acid testing (NAT) to quantify HBV DNA, are hardly available and affordable in resource-limited countries. We therefore assessed the performance of a novel immunoassay, hepatitis B core-related antigen (HBcrAg), as an inexpensive (US$ <15/assay) alternative to NAT to diagnose clinically important HBV DNA thresholds (≥2000, ≥20 000, and ≥200 000 IU/mL) and to select patients for antiviral therapy in Africa. METHODS: Using a well-characterized cohort of treatment-naive patients with chronic HBV infection in The Gambia, we evaluated the accuracy of serum HBcrAg to diagnose HBV DNA levels and to indicate treatment eligibility determined by the American Association for the Study of Liver Diseases, based on reference tests (HBV DNA, hepatitis B e antigen, alanine aminotransferase, liver histopathology, and/or FibroScan). RESULTS: A total of 284 treatment-naive patients were included in the analysis. The area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity of serum HBcrAg were 0.88 (95% confidence interval [CI], .82-.93), 83.3%, and 83.9%, respectively, to diagnose HBV DNA ≥2000 IU/mL; and 0.94 (95% CI, .88-.99), 91.4%, and 93.2% for ≥200 000 IU/mL. A simplified treatment algorithm using HBcrAg without HBV DNA showed high AUROC (0.91 [95% CI, .88-.95]) with a sensitivity of 96.6% and specificity of 85.8%. CONCLUSIONS: HBcrAg might be an accurate alternative to HBV DNA quantification as a simple and inexpensive tool to identify HBV-infected patients in need of antiviral therapy in low- and middle-income countries.

Implantation of adipose-derived regenerative cells enhances ischemia-induced angiogenesis.

OBJECTIVE: Therapeutic angiogenesis using autologous stem/progenitor cells represents a novel strategy for severe ischemic diseases. Recent reports indicated that adipose tissues could supply adipose-derived regenerative cells (ADRCs). Accordingly, we examined whether implantation of ADRCs would augment ischemia-induced angiogenesis. METHOD AND RESULTS: Adipose tissue was obtained from C57BL/6J mice, and ADRCs were isolated using standard methods. ADRCs expressed stromal cell-derived factor 1 (SDF-1) mRNA and proteins. Hind limb ischemia was induced and culture-expanded ADRCs, PBS, or mature adipocytes (MAs) as control cells were injected into the ischemic muscles. At 3 weeks, the ADRC group had a greater laser Doppler blood perfusion index and a higher capillary density compared to the controls. Implantation of ADRCs increased circulating endothelial progenitor cells (EPCs). SDF-1 mRNA abundance at ischemic tissues and serum SDF-1 levels were greater in the ADRC group than in the control group. Finally, intraperitoneal injection of an anti-SDF-1 neutralizing antibody reduced the number of circulating EPCs and therapeutic efficacies of ADRCs. CONCLUSIONS: Adipose tissue would be a valuable source for cell-based therapeutic angiogenesis. Moreover, chemokine SDF-1 may play a pivotal role in the ADRCs-mediated angiogenesis at least in part by facilitating mobilization of EPCs.

Novel and highly sensitive immunoassay for total hepatitis B surface antigen, including that complexed with hepatitis B surface antibody.

BACKGROUND: Hepatitis B surface antigen (HBsAg) is used as a clinical marker of hepatitis B virus (HBV) infection. However, conventional HBsAg assays have so far failed to accurately detect HBsAg in blood because of interference by patient-derived antibodies against HBsAg (HBsAb). METHODS: We developed a novel, fully automated assay system that can detect total HBsAg in blood, including antigens complexed with HBsAb. The immunoassay inactivates HBsAb via a simple pretreatment step to dissociate the HBsAg molecule from HBsAg-HBsAb complexes and thereby estimate total HBsAg. Accordingly, the test has been termed the "immunoassay for total antigen including complex via pretreatment (iTACT)-HBsAg." RESULTS: The recovery rate of HBsAg in the presence of HBsAb was greater than 87 % at a cutoff value set at 5.0 mIU/mL on the basis of data from 545 healthy controls. Analyses using serial serum samples from 25 HBV carriers who became negative for HBsAg during follow-up showed that the iTACT-HBsAg could detect HBsAg over a period of years despite a loss in detection by conventional assays and was able to detect HBsAg in 39 (53 %) of 73 samples with HBsAb. CONCLUSIONS: The new iTACT-HBsAg assay appears to detect total HBsAg with high sensitivity, even in the presence of HBsAb, and may useful in identifying subclinical or occult HBV carriers.