Certain patients with hepatitis B virus (HBV) infection present with persistently low levels of serum hepatitis B surface antigen (HBsAg) and have been indicated to have low rates of HBV nucleic acid replication. To explore the serological and molecular epidemiological characteristics of HBV population with low-level HBsAg in the present study, associated serum markers and virologic genotype detection were performed accordingly. Determination of HBV markers was performed using a chemiluminescence immunoassay from which 2,544 out of 45,256 adults who underwent routine health examination were tested positive for HBsAg. HBV DNA was detected by real-time fluorescent quantitative PCR. The patients were divided into low-level and high-level groups, according to their HBsAg levels (cut-off value, 10 IU/ml). The prevalence and levels of HBsAg positivity and HBV DNA in patients with HBV infection were analyzed by age, sex, serological pattern and clinical type. The fibrosis status of patients with low-level HBsAg was assessed by determining the aspartate aminotransferase-to-platelet ratio (APRI), and sequencing was employed to determine serotypes and genotypes. HBV-infected patients with low-level HBsAg (<10 IU/ml) accounted for 15.41% of the 2,544 HBsAg-positive patients, and the prevalence of HBsAg positivity exhibited a tendency to increase with age. The male-to-female ratio was ~1.9:1, and the average age was 54.98±16.28 years among HBV-infected patients with low-level HBsAg. The major serological pattern and clinical types were HBsAg/antibody against hepatitis Be antigen (anti-HBe)/antibody against hepatitis B core antigen (anti-HBc)-positive (94.90%) and chronic asymptomatic (ASC) (97.95%), respectively. HBV DNA exhibited a low-level of replication and the prevalence of HBV DNA positivity assessed by the routine method and by the enrichment method was 27.74% (97/392) and 45.92% (180/392), respectively. No significant differences among the age groups were identified in the different HBsAg level groups (P>0.05). The prevalence of HBV DNA positivity was associated with HBsAg only in patients with serological pattern HBV-M2 (HBsAg/anti-HBe/anti-HBc-positive) in the low-level HBsAg group (odds ratio: 1.30; 95% CI: 1.15–1.47; P<0.05). The APRI had no association with age, HBsAg, HBV DNA level or liver function index in ASC patients in the low-level HBsAg group (P>0.05). The prevalence of the serotype adw and genotype B was 85.53 and 89.47%, respectively. Further improvement in the systematic study of populations with low-level HBsAg has important clinical and epidemiological significance for improving the detection of HBV serological markers, elucidating the mechanisms leading to low-level HBsAg, overcoming immune tolerance to eliminate HBV infection and preventing HBV transmission.

This study aimed to investigate hepatitis B virus (HBV) infection in military personnel in eastern China, which will provide a basis for the prevention of HBV infection.A total of 15,508 soldiers and 2386 officers were recruited from military camps in eastern China. The markers, deoxyribonucleic acid, serotypes, and genotypes of HBV in serum were detected and analyzed.Hepatitis B surface antigen (HBsAg) positive rate was 0.44% in soldiers, in whom the low-level HBsAg accounted for 88.24%. The HBsAg positive rate was 1.72% in officers in whom the low-level HBsAg accounted for 12.20%. There were significant differences in the prevalence of high-level and low-level HBsAg, HBV serotypes, HBV DNA positive rate, and mean log HBV DNA between officers and soldiers (P < .05). Compared with the conventional method for HBV DNA extraction, the enrichment method for HBV DNA extraction could significantly improve the positive rate and quantification of HBV DNA by real-time fluorescence quantitative polymerase chain reaction (P < .05). Sequencing of S gene in HBV was used for the determination of serotype and genotype of HBV. The sequencing success rate was significantly different between soldiers and officers (P < .05) as well as between high-level HBsAg group and low-level HBsAg group (P < .05). Significant difference was also observed in the genotype distribution between soldiers and officers (P < .05).HBV infection displays a low prevalence and a low epidemic state, and the prevalence of low-level HBsAg is higher in soldiers. We should pay attention to improve the quality of conscription examination as well as emphasize the surveillance, prevention, and protection of HBV infection in military officers.

BackgroundThe aim of this study was to investigate the clinical characteristics of individuals with chronic hepatitis B virus (HBV) infection with persistent low levels of hepatitis B surface antigen (HBsAg) and to undertake a correlation analysis of the clinical characteristics.Material/MethodsThe study included 1,204 subjects with chronic HBV infection. Serum HBsAg, HBV envelope antigen (HBeAg), and HBV core antigen (HBcAg) levels were measured using the chemiluminescent microparticle immunoassay (CMIA) and the neutralization test. HBV DNA was measured using real-time fluorescence quantitative polymerase chain reaction (RT-FQ-PCR).ResultsThere were 1,023 subjects in the high-level HBsAg group (HBsAg level ≥10 IU/mL) and 181 subjects in the low-level HBsAg group (HBsAg level <10 IU/mL). In the low-level HBsAg group, the main serological pattern (93.37%) was HBsAg and HBeAg and HBcAg-positive (HBV-M2), and the asymptomatic carrier (ASC) status was 98.34%. The low-level HBsAg group had a lower HBV DNA-positive rate compared with the high-level HBsAg group (40.33% vs. 75.07%), with a normal distribution across all age groups (P>0.05). The low-level HBsAg group included an older age group. A low-level of HBsAg was positively correlated with a low level of replication of HBV DNA (r=0.452).ConclusionsThe findings of this study showed that individuals with chronic HBV infection and sustained low-levels of HBsAg were an older population and had a lower level of replicating HBV DNA when compared with individuals with high levels of HBsAg, and the majority (93.7%) were also HBsAg and HBeAg and HBcAg-positive.

Infectious diseases are a major global cause of morbidity and mortality, seriously affecting public health and socioeconomic stability. Since infectious diseases can be caused by a wide variety of pathogens with similar clinical manifestations and symptoms that are difficult to accurately distinguish, selecting the appropriate diagnostic techniques for the rapid identification of pathogens is crucial for clinical disease diagnosis and public health management. However, traditional diagnostic techniques have low detection rates, long detection times and limited automation, which means that they do not meet the requirements for rapid diagnosis. Recent years have seen continuous developments in molecular detection technology, which has a higher sensitivity and specificity, shorter detection time and increased automation, and performs an important role in the early and rapid detection of infectious disease pathogens. The present study summarizes recent progress in molecular diagnostic technologies such as PCR, isothermal amplification, gene chips and high-throughput sequencing for the detection of infectious disease pathogens, and compares the technical principles, advantages and disadvantages, applicability and costs of these diagnostic techniques.

This study aimed to establish a general and efficient dissociation technique for detecting antibodies in circulating immune complexes (CICs) in serum and to evaluate its clinical application. CICs were efficiently separated from specimens using polyethylene glycol double-precipitation. The best conditions for anti-HBs dissociation from HBsAg-ICs were a pH of 1.80, incubation at 15 °C for 5-10 min, and detection within 10 min after neutralization. The mean dissociation rate, reproducibility, mean dissociation recovery rate and specificity of the new technique were 64.3%, < 5.97, 95.4 and 100%, respectively. They had a favourable linear relationship (r = 0.9932), and the stability of the reagents exceeded 24 months, except the CIC antibody dissociation reagent (> 12 months). Conditions for the dissociation of other CICs tested were similar, but there were differences in the rate of antibody dissociation. Different HBV-M patterns had significantly different levels and rates of antibody dissociation from HBsAg-IC (P < 0.05), and the detection rates of the corresponding antibodies in HCV, core-anti-HCV core antibody (HCV-ICs), HIV P24-anti-HIV P24 antibody (HIV-ICs), insulin-anti-insulin antibody (INS-ICs) and thyroid globulin-anti-thyroid globulin antibody CICs (TG-ICs) were 34.8, 66.7, 20 and 14.3%, respectively. These data suggest that our CIC antibody dissociation technique is a good general pretreatment technique for the detection of antibodies after the precipitation, separation and dissociation of multiple CICs.