Establishment and methodological evaluation of a chemiluminescence assay for detection of anti-envelope protein (E1, E2) antibodies in the serum of hepatitis C virus-infected patients.

BACKGROUND: To establish a chemiluminescence method for detecting anti-E1 and anti-E2 antibodies in the serum of patients with hepatitis C virus (HCV) infection. METHODS: The microplate was coated with recombinant envelope proteins E1 and E2 by indirect method, respectively, and the kits for detecting anti-E1 and anti-E2 antibodies were prepared. The methodological indexes were evaluated. RESULTS: The methodological indexes of the kits were as follows: precision test (the variation coefficient of anti-E1 antibody 6.71%-8.95% for within run and 9.91%-12.16% for between run, the variation coefficient of anti-E2 antibody 6.06%-8.44% for within run and 10.77%-13.98% for between run, respectively). The blank limit and detection limit were 1.18 RLIR and 3.16 RLIR for the anti-E1 antibody, and 1.26 RLIR and 3.32 RLIR for the anti-E2 antibody, respectively. The correlation coefficients (r) of anti-E1 and anti-E2 were 0.9963 and 0.9828, the analysis and measurement ranges (AMR) were 1.66-41.28 RLIR and 1.55-19.46 RLIR, and the average recovery was 96.4% and 93.7%, respectively. The rheumatoid factor and other positive serum samples had no interference or cross-reaction to the test, and the kits were stable within 15 months. The positive rates of anti-E1 and anti-E2 antibodies in 45 patients with HCV infection were 35.6% (16/45) and 44.4% (20/45), respectively. CONCLUSIONS: The kits for detecting anti-E1 and anti-E2 meet the requirements of methodology, and can be used in screening diagnosis, disease monitoring, prognosis evaluation, disease mechanism, and epidemiological studies of HCV infection. The HCV envelope proteins E1 and E2 have an immune response in HCV-infected patients.

Development and application of a universal extraction-free reagent based on an algal glycolipid.

In this study, we independently developed a universal nasopharyngeal swab extraction-free reagent based on a trehalose lipid for the rapid detection of pathogen nucleic acids in respiratory infectious diseases. By comparing the isothermal amplification results of a 2019-nCoV pseudovirus solution treated with different components of the extraction-free reagent, we determined the optimal composition of the extraction-free reagent to be a mixed solution of 10 mmol L-1 tris-HCl containing 0.05 mmol L-1 EDTA (TE solution), 5% glycine betaine, 0.5% Triton X-100, and 1.5% trehalose lipid. The results showed that the extraction-free reagent could cleave DNA viruses, RNA viruses, and bacteria to release nucleic acids and did not affect the subsequent nucleic acid amplification. Its efficiency was consistent with that of magnetic bead extraction. Real-time fluorescence quantitative PCR was used to analyze the stability and repeatability of the detection results of the samples treated with the extraction-free reagent and the sensitivity of the extraction-free reagent. The results showed that the extraction-free kit could stably store the pathogen nucleic acid for at least 24 hours, the detection repeatability was satisfactory, and there was no incompatibility with the detection limits of various manufacturers' nucleic acid detection reagents. In conclusion, the established nucleic acid extraction-free method can effectively lyse respiratory infectious disease pathogens to release nucleic acids (DNA and RNA) at room temperature and can directly amplify nucleic acids without extraction steps. This method takes a short time and has high efficiency. The released nucleic acid met the requirements of molecular biological detection methods such as real-time fluorescence quantitative PCR (qPCR), reverse transcription-polymerase chain reaction (RT-PCR), and isothermal nucleic acid amplification (INAA).

Advances in the application of molecular diagnostic techniques for the detection of infectious disease pathogens (Review).

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 high­throughput sequencing for the detection of infectious disease pathogens, and compares the technical principles, advantages and disadvantages, applicability and costs of these diagnostic techniques.

Establishment and Evaluation of Recombinant Expression of HCV Transmembrane Protein (p7) and Detection of Anti-p7 Antibody in Serum of HCV-Infected Patients by Chemiluminescence.

OBJECTIVE: Our aim was to establish a chemiluminescence method for detecting anti-transmembrane protein (p7) antibody in the serum of patients with hepatitis C virus (HCV) infection. METHODS: The p7 gene was amplified by polymerase chain reaction using the plasmid PUC-p7 containing the p7 nucleic acid sequence of the HCV 1b genotype as the template, and recombinant plasmid pGEX-KG-p7 was constructed. After p7 fusion, the protein was induced and expressed in the prokaryote, extracted, and purified; the anti-p7 antibody detection kit was prepared, and its efficacy was evaluated. RESULTS: The plasmid pGEX-KG-p7 was constructed correctly, and p7 fusion protein was obtained. The methodological indexes of the kit, the precision test, blank limit and detection limit, etc, met the requirements. The positive rate of serum anti-p7 antibody in 45 patients with HCV infection was 20%. CONCLUSIONS: The kit can be used in screening diagnosis, condition monitoring, prognosis, and disease mechanism and epidemiological study of HCV infection. The p7 protein has immune response in HCV-infected patients.

Analysis of S gene characteristic sequences and changes in properties of protein expression in HBV ASCs with low-level HBsAg.

Objective: We detected the serum HBsAg immune complex (HBsAg-CIC) and sequenced the HBV S gene in these patients to reveal the association between sustained low-level expression of HBsAg and mutated S gene sequence characteristics, protein function changes, and HBsAg immune complex formation. Methods: A total of 204 samples were collected and divided into high-level (n = 60, HBsAg level >10 IU/ml) and low-level (n = 144, HBsAg level ≤ 10 IU/ml) HBsAg groups. The clinical and epidemiological data of the two groups were statistically compared. According to different serological patterns and genotypes, the HBsAg-CIC results of the high-level and low-level HBsAg groups were divided into different subgroups, and then the HBsAg-CIC positive rates among different subgroups were compared. We sequenced the S gene of HBV from the two groups and identified the relevant mutations in the MHR of the S gene. In addition, we compared the changes in HBsAg protein properties and functions after hot spot mutation in the MHR of the S gene. Results: Comparing the positive rates of HBsAg-CIC under different serological patterns and genotypes in the two groups, the HBsAg-CIC positive rate was higher in the low-level HBsAg group. Moreover, there was weak correlation between HBsAg-CIC and HBsAg or HBV DNA in both groups (r = 0.32, 0.27, 0.41, 0.48; P < 0.05). Sequencing of S gene in the two groups, showed that the hot-spot mutations were T126A, M133L/T/S, and F134L/T/I in MHR of S gene of genotype B, and hot-spot mutations were Q101R and I126S/T in MHR of S gene of genotype C. Additionally, the positive rate of MHR mutation in the S gene from HBsAg-CIC positive patients was higher in the low-level HBsAg group. Conclusion: The host immune process of clearing HBV seems to have multiple site mutations in MHR, which changes the physicochemical properties and functions of HBsAg and intensifies the formation of HBsAg-CIC, thus avoiding the effective recognition of HBsAg by the host and resulting in immune tolerance between the host and HBV, which may be one of the formation mechanisms of sustained low-level expression of HBsAg in the serum of HBV-infected persons.

[Detection of serum anti-NS2 antibody and recombinant hepatitis C virus nonstructural protein 2 (NS2): its development and evaluation].

Objective To express the recombinant HCV NS2, establish and evaluate the detection method of serum anti-ns2 antibody based on chemiluminescence. Methods Using the NS2 sequence plasmid of HCV 1b genotype (PUC-NS2) as the template, a recombinant plasmid containing the whole NS2 sequence (pGEX-KG-NS2) was constructed. Prokaryotic expression of NS2 protein was induced. The purified NS2 fusion protein was coated on the microplate, and the anti-NS2 antibody detection kit was prepared based on chemiluminescence, and the methodological index was evaluated. Results NS2 fusion protein with relative molecular weight (Mr) of about 51 000 was successfully induced and expressed, and a serum anti-NS2 antibody detection kit was synthesized. Methodological evaluation of kit: Precision test showed favorable results (intra batch coefficient of variation [CV] was 4.60%~9.17%, inter batch CV was 6.62%~10.09%). The relative luminous intensity ratio (RLIR) of the blank limit and the detection limit were 1.57 and 4.80 (r=0.9870), respectively, and the analytical measurement range (AMR) was 1.63~44.50 RLIR. Accuracy experiments: The average recovery was 99.4%. The positive serum samples such as rheumatoid factor had no cross reaction to this test, and the kit was stable within 15 months. The positive rate of anti-NS2 antibody in serum of 45 HCV infected patients was 20% (9/45). Conclusion The prokaryotic expression of HCV NS2 fusion protein is successfully obtained, and the anti-NS2 antibody detection kit in serum is developed.

Research Progress on the Mechanism of Persistent Low-Level HBsAg Expression in the Serum of Patients with Chronic HBV Infection.

Among HBV-infected persons, there is a group of people with hepatitis B surface antigen (HBsAg) showing persistently low levels of expression. The production of low-level HBsAg does not mean a good outcome of chronic HBV infection. Patients still have virus replication and sustained liver damage, and they have the potential to transmit the infection. This risk poses a challenge to clinical diagnosis and blood transfusion safety and is a major concern of experts. However, the mechanism behind persistent low-level HBsAg expression in serum is not completely clear, and complete virus clearance by the host is vital. In this review, we summarize the research progress on the mechanism behind low-level expression of HBsAg in patients with chronic HBV infection in recent years.

Coexistence of two blaKPC-2 genes in a blaNDM-1-carrying multidrug-resistant ST15 Klebsiella pneumoniae isolate recovered from cerebrospinal fluid in China.

OBJECTIVES: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is increasingly reported worldwide and has posed a serious challenge for public health. Here we report the complete genome sequence of a multidrug-resistant (MDR) K. pneumoniae carrying one blaNDM-1 and two copies of blaKPC-2 genes isolated from a cerebrospinal fluid specimen in China. METHODS: The minimal inhibitory concentrations (MICs) of 26 antimicrobial agents against K. pneumoniae strain KP46 were measured. The complete genome sequence of KP46 was determined using Illumina and Nanopore platforms. The derived short and long reads were assembled using Unicycler. Multilocus sequence typing (MLST), antimicrobial resistance genes, virulence genes, and plasmid replicons were predicted in silico using the BacWGSTdb server. The phylogenetic relationship between KP46 and 454 ST15 K. pneumoniae strains obtained from NCBI GenBank database was analysed based on a core genome MLST (cgMLST) strategy. RESULTS: K. pneumoniae strain KP46 was resistant to all antimicrobial agents tested, except for tigecycline, colistin, cefiderocol, and fosfomycin. The genome sequence of KP46 belonged to sequence type 15 (ST15), which contained seven circularized contigs comprising 5 674 521 bp, including one chromosome and six plasmids. Serval antimicrobial resistance genes were identified, including a blaNDM-1 gene located in a 53 096 bp IncX3 plasmid, and two copies of blaKPC-2 gene located both in a 103 807 bp IncX6 and an 88 164 bp IncFII plasmid, respectively. The most closely related strain was another ST15 strain also isolated from China with five cgMLST loci differences. CONCLUSION: We reported the first complete genome sequence of a K. pneumoniae ST15 clinical isolate coharbouring blaNDM-1 and two copies of blaKPC-2 in China. This study will provide insight into the antimicrobial resistance mechanisms and phylogeny of carbapenem-resistant ST15 K. pneumoniae.

Analysis of the Complete Genomes of Enterovirus 71 Subtypes in China.

Enterovirus 71 (EV-A71) is one of the most pathogens to hand, foot, and mouth disease (HFMD) as well as neurological complications in young children. Molecular characteristic of EV-A71 is important to prevent the virus outbreak. Here, the complete genomes of EV-A71 from China between 1998 and 2019 were downloaded from GenBank. The phylogenetic trees were developed by MEGA7.0 software, and the complete genetic epidemiological characteristics and amino acid mutations of EV-A71 from China were also analysed. The results showed that major epidemic EV-A71 subtype was C4b before 2004, while it turned to C4a after 2004 in mainland China, and C4 and B5 were major subtypes in Taiwan. VP1, VP4, 2C, 3C, 3D, and complete genome sequence can be used for virus genotyping, and VP1, VP4, and complete genomes have obvious advantages over other segments. There were many significant mutations in the viral complete genome sequence. This study indicated that the major C4 and B5 subtypes will contribute to the development of vaccines and drugs of EV-A71 for prevention and monitoring of EV-A71-associated HFMD in China.

Traditional Chinese Medicine Enema Therapy in a Patient With a Confirmed Negative SARS-CoV-2 Test in the Respiratory Tract but Positive in the Intestinal Tract: A Case Report.

We report the case of a 43-year-old man who was infected with SARS-CoV-2 in February 2020 and actively cooperated with treatment in the hospital. During the course of treatment, we found that the respiratory SARS-CoV-2 nucleic acid became negative, but remained positive in the intestinal tract. As a result, we adjusted the treatment plan to include traditional Chinese medicine enema treatment. The patient had negative intestinal SARS-CoV-2 nucleic acid test within 4 days, and the subsequent repeated review of intestinal SARS-CoV-2 nucleic acid was negative, and the virus was undetectable. It is suggested that traditional Chinese medicine enema treatment may be helpful to remove the SARS-CoV-2 in the intestines of patients with COVID-19 infection, and may support the treatment of patients with respiratory SARS-CoV-2 nucleic acid negative and positive in the intestinal tract.

Clinical characteristics and association analysis of persistent low-level HBsAg expression in a physical examination population with HBV infection.

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.

[Corrigendum] Sequence analysis of the Pre­S gene in chronic asymptomatic HBV carriers with low­level HBsAg.

After the publication of the article, the authors realize that the grant funding number for the support that they received from Natural Science Foundation of Zhejiang Province appeared incorrectly in the Funding section of the paper: This should have been featured as grant no. LY15H200001 (i.e., with an 'L' at the start of the number). The authors regret that this error was not corrected prior to the publication of their paper, and apologize to the funders for any inconvenience caused. [the original article was published in International Journal of Molecular Medicine 42: 2689-2699, 2018; DOI:10.3892/ijmm.2018.3831].

Establishment and evaluation of a general dissociation technique for antibodies in circulating immune complexes.

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.

Analysis of clinical characteristics and S gene sequences in chronic asymptomatic HBV carriers with low-level HBsAg.

BACKGROUND: During the natural hepatitis B virus (HBV) infection process, some infected subjects are characterized by a sustained low serum HBV surface antigen (HBsAg) expression level. Most members in this population are chronic asymptomatic HBV carriers (ASCs). To elucidate the mechanism underlying low-level HBsAg expression in ASCs, we sequenced the HBV S gene in these patients to reveal specific sequence characteristics. METHODS: Overall, 1308 cases of chronic ASCs were grouped according to their HBsAg serum expression levels (10 IU/mL). The clinical characteristics of the population were analysed in detail. The HBV S gene was sequenced from 276 ASC cases with low-level HBsAg expression. Additionally, 100 of 1032 ASC cases with high-level HBsAg expression were randomly selected for HBV S gene sequencing based on age matching according to the low-level HBsAg group. A comparative analysis was conducted with the HBV S gene sequences from ASCs with low HBsAg expression and the HBV reference S gene sequences from ASCs with high HBsAg expression. RESULTS: The population with low-level HBsAg expression displayed the following primary clinical characteristics: mostly chronic asymptomatic HBV carriers, older age (mean age 55.09 years), HBsAg/anti-HBe/anti-HBc (core) positivity as the main serological pattern (97.1%), low HBV DNA replication (1.32 ± 1.60 log10 IU/mL), a low HBV-DNA positive rate (45.65%) and primarily genotype B (82.54%) and serotype adw (84.13%). The comparative analysis of the HBV S gene sequences from ASCs with low-level HBsAg showed significant mutations (including co-mutations) on both sides of the main hydrophilic region (MHR). CONCLUSION: Significant mutations in multiple regions and at multiple sites (including co-mutations) on both sides of the MHR may be one cause of the low HBsAg expression level in this population.

An epidemiological survey of HBV infection and low-level HBsAg in military camps in eastern China.

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.

Sequence analysis of the Pre-S gene in chronic asymptomatic HBV carriers with low-level HBsAg.

In a hepatitis B virus (HBV)­infected population, persistently low expression levels of serum HBV serum antigen (HBsAg) are present, particularly in chronic asymptomatic HBV carriers (ASCs). The present study sequenced the HBV Pre­S gene, and aimed to elucidate its features in ASCs with low HBsAg expression compared with in the established HBV Pre­S reference gene sequences from ASCs with high HBsAg expression. A total of 1,308 ASCs were grouped according to HBsAg serum levels (cut­off value, 10 IU/ml), and clinical characteristics were analyzed in detail. The HBV Pre­S gene was sequenced in 276 ASCs with low­level HBsAg; in addition, 100 of the remaining 1,032 ASCs with high­level HBsAg were randomly selected for HBV Pre­S gene sequencing on the basis of age matching with the low­level HBsAg group. Comparative analysis of the gene sequences from these groups was subsequently conducted. The major clinical features of the population with low­level HBsAg were as follows: Most were ASCs with chronic HBV infection; 97.1% were HBsAg/anti­HBe/anti­HBc­positive; 82.54% carried the B genotype; and 84.13% displayed the adw serotype. The results indicated that there were novel and meaningful mutations, including co­mutations, at numerous loci and sites in the Pre­S gene, as well as deletion mutations in the Pre­S2 gene. These mutations in the Pre­S1 and Pre­S2 gene fragments accounted for 65.38% (68/104) of the 104 B genotype cases in the low­level HBsAg group and 90.91% (20/22) of the 22 C genotype cases in the low­level HBsAg group, respectively. In conclusion, Pre­S gene mutations may be associated with HBV replication defects, which may be the cause of the observed low expression levels of HBsAg.

Clinical Characteristics and Correlation Analysis of Subjects with Chronic Hepatitis B Virus (HBV) Infection and Sustained Low Levels of Hepatitis B Surface Antigen (HBsAg).

BACKGROUND The 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 AND METHODS The 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). RESULTS There 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). CONCLUSIONS The 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.

A novel general and efficient technique for dissociating antigen in circulating immune complexes.

Circulating immune complexes (CICs) are produced during the immune response. It is more clinically important to establish a general and efficient CICs dissociation technique for the detection of antigens for CICs other than the detection of free antigens in the serum. Polyethylene glycol (PEG) two-precipitation separation and glycine-HCl as a buffer system were employed to develop a general and efficient buffer dissociation technique to separate CICs from serum and dissociate antigens from CICs. The measurement value of new PEG two-precipitation separation technique was higher than traditional PEG precipitation separation technique. There were slight differences in the dissociation conditions of HCV Core-IC, HIV P24-IC, Ins-IC and TG-IC as compared to HBsAg-IC. The detection of antigens in HBsAg-IC, HCV Core-IC, HIV P24-IC, Ins-IC and TG-IC with this technique was superior to that with HCl Dissociation, Trypsin Digestion or Immune Complex Transfer technique. PEG two-precipitation dissociation technique may reduce macromolecular protein and the adhesion of free antigens during the co-precipitation, which increases the efficiency of separation and precipitation of CICs. This technique also avoids the damage of reagents to antigens, assuring the repeatability, reliability and validity. Thus, this technique is application in samples negative or positive for free antigens.

Epidemiology and transmission characteristics of human adenovirus type 7 caused acute respiratory disease outbreak in military trainees in East China.

BACKGROUND: Human adenovirus type 7 (HAdV7) is globally attracting great concern as its high morbidity and severity in respiratory diseases, especially in Asia. OBJECTIVE: To investigate the clinical and epidemiologic characteristics of HAdV7 infection outbreak in East China. METHODS: The clinical samples were collected from the patients of an ARD outbreak in East Chinafor the detection of causative pathogens by multiplex PCR. The molecular type of human adenovirus isolates were identified by sequencing and homologous comparison based on their hexon genes. The spatiotemporal dynamics of global HAdV7 was investigated using the phylogenetic and phylogeographic analyses. Total 67 referenced HAdV7 hexon sequences (>800 bp) from GenBank were selected for constructing the maximum likelihood tree by MEGA 5.1.0, grouped according to the tree topology for the further migration analysis by PAUP* 4.0 and MigraPhyla 1.0 b to understand the transmission patterns of HAdV7 in global epidemics. RESULTS: The results showed HAdV7 as the causative pathogen in this outbreak, and the outbreak strains had the hexon sequences highly identical with the isolates in Shaanxi (2012). The origin of HAdV7 was inferred as California, meanwhile a total of 21 migration routes were acquired. HAdV7 in this outbreak was statistically proven dispersed from Shaanxi province (2012). CONCLUSIONS: The analyses of epidemiology and transmission pattern of HAdV7 would not only enrich the molecular biological basic database but also provide theoretical basis for HAdV7 prevention and control strategy.

Laboratory diagnosis of avian influenza virus H7N9 infection in a renal transplant recipient.

A renal transplant recipient who had atypical clinical manifestations, unclear epidemiological exposure history and negative results from influenza virus antigen and nucleic acid amplification in throat swab specimens was admitted into our hospital on April 17, 2013. He was finally diagnosed as avian influenzavirus H7N9 infection. Here, we reviewed the epidemiological, clinical and laboratory findings of this patient. We speculated that the specimens should be collected repeatedly at different sites for suspected cases or special cases needing differential diagnosis; different methods or kits should be used for laboratory testing; atypical clinical manifestations caused by the special nature of patients such as long-term use of immunosuppressive agents and autoimmune diseases should also be taken into account.