Long-term efficacy of a recombinant hepatitis E vaccine in adults: 10-year results from a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Hepatitis E virus (HEV) is a frequently overlooked causative agent of acute hepatitis. Evaluating the long-term durability of hepatitis E vaccine efficacy holds crucial importance.

METHODS

This study was an extension to a randomised, double-blind, placebo-controlled, phase-3 clinical trial of the hepatitis E vaccine conducted in Dontai County, Jiangsu, China. Participants were recruited from 11 townships in Dongtai County. In the initial trial, a total of 112 604 healthy adults aged 16-65 years were enrolled, stratified according to age and sex, and randomly assigned in a 1:1 ratio to receive three doses of hepatitis E vaccine or placebo intramuscularly at month 0, month 1, and month 6. A sensitive hepatitis E surveillance system including 205 clinical sentinels, covering the entire study region, was established and maintained for 10 years after vaccination. The primary outcome was the per-protocol efficacy of hepatitis E virus vaccine to prevent confirmed hepatitis E occurring at least 30 days after administration of the third dose. Throughout the study, the participants, site investigators, and laboratory staff remained blinded to the treatment assignments. This study is registered with ClinicalTrials.gov (NCT01014845).

FINDINGS

During the 10-year study period from Aug 22, 2007, to Oct 31, 2017, 90 people with hepatitis E were identified; 13 in the vaccine group (0·2 per 10 000 person-years) and 77 in the placebo group (1·4 per 10 000 person-years), corresponding to a vaccine efficacy of 83·1% (95% CI 69·4-91·4) in the modified intention-to-treat analysis and 86·6% (73·0 to 94·1) in the per-protocol analysis. In the subsets of participants assessed for immunogenicity persistence, of those who were seronegative at baseline and received three doses of hepatitis E vaccine, 254 (87·3%) of 291 vaccinees in Qindong at the 8·5-year mark and 1270 (73·0%) of 1740 vaccinees in Anfeng at the 7·5-year mark maintained detectable concentrations of antibodies.

INTERPRETATION

Immunisation with this hepatitis E vaccine offers durable protection against hepatitis E for up to 10 years, with vaccine-induced antibodies against HEV persisting for at least 8·5 years.

FUNDING

National Natural Science Foundation of China, Fujian Provincial Natural Science Foundation, Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences, and the Fundamental Research Funds for the Central Universities.

Profile of clinical characteristics and serologic markers of sporadic hepatitis E in a community cohort study

Hepatitis E virus (HEV) is a pathogen of global significance, but the value of HEV-related markers in the diagnosis of hepatitis E remains controversial. Previous studies on hepatitis E profiles have been mainly cross-sectional and conducted among inpatients in large hospitals, and hepatitis E cases have been primarily defined by limited partial markers. In this community-based study, 4,110 active hepatitis cases from a population of nearly 600,000 were followed over 48 months and serial serum samples were collected. Both HEV pathogen (HEV RNA and antigen) and anti-HEV antibody markers were used to determine HEV infection status and the relationship between hepatitis and HEV infection. In total, 98 hepatitis E patients were identified and all available isolates from 58 patients belonged to HEV genotype 4. The mean age of the patients was 58.14 years, with an overwhelming proportion of males (70.4%). Hepatitis E accounted for 22.86% of active hepatitis cases with alanine aminotransferase levels ≥15.0-fold the upper limit of normal, suggesting the need to include HEV in routine testing for these patients. Ninety-two hepatitis E patients were positive for at least 2 of HEV antigen, anti-HEV IgM, and HEV RNA markers at presentation, and 90.22% of them were positive for HEV antigen and anti-HEV IgM. HEV antigen, HEV RNA, and anti-HEV IgM positivity were observed in 89.80%, 82.65%, and 93.88% of hepatitis E patients at presentation, respectively. However, only 57.14% of anti-HEV IgM positivity occurred in hepatitis E patients. These findings will advance our understanding of hepatitis E and improve diagnosis.

Transcriptome Profiling of Male Adult Angiostrongylus cantonensis

Background

The pathogen of angiostrongyliasis is the parasite Angiostrongylus cantonensis, and the transcriptome profiling of the male adult was unclear. We aimed to understand how the male adults adapt, so the expression profile of A. cantonensis adult males was analyzed.

Methods

In order to improve the understanding of the transcriptome of adult males, RNA from three groups of male adult A. cantonensis was extracted and reverse transcribed to construct cDNA libraries. After sequencing, annotation of unigenes and transcripts was performed by querying the NR (Non-Redundant Protein Sequence Database), GO (Gene Ontology) and COG/KOG (Clusters of Orthologous Groups of proteins/euKaryotic Ortholog Groups) databases.

Results

For each group of adults, 43,260,894 raw reads and 43,200,341 clean reads were obtained. After successful assembly, 87,649 unigenes and 146,895 transcripts were obtained. Annotation of the unigenes and transcripts was identical and male adults expressed a series of genes encoding proteins specific to the male gender at the adult stage, such as proteins involved in energy metabolism, energy synthesis and transport. Expression of the ribosome pathway suggests a relationship with the physical activities during the adult male stage.

Conclusion

The transcriptome analysis is a good reference to understand further the expression profile of male adult A. cantonensis.

Case Report: Chronic hepatitis E virus Infection in an individual without evidence for immune deficiency

Chronic hepatitis E virus (HEV) infection occurs mainly in immunosuppressed populations. We describe an investigation of chronic HEV infection of genotype 3a in an individual without evidence for immune deficiency who presented hepatitis with significant HEV viremia and viral shedding. We monitored HEV RNA in plasma and stools, and assessed anti-HEV specific immune responses. The patient was without apparent immunodeficiency based on quantified results of white blood cell, lymphocyte, neutrophilic granulocyte, CD3+ T cell, CD4+ T cell, and CD8+ T cell counts and CD4/CD8 ratio, as well as total serum IgG, IgM, and IgA, which were in the normal range. Despite HEV specific cellular response and strong humoral immunity being observed, viral shedding persisted up to 10⁹ IU/mL. After treatment with ribavirin combined with interferon, the indicators of liver function in the patient returned to normal, accompanied by complete suppression and clearance of HEV. These results indicate that HEV chronicity can also occur in individuals without evidence of immunodeficiency.

Potential of antibody pair targeting conserved antigenic sites in diagnosis of SARS-CoV-2 variants infection

Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has become disaster for human society. As the pandemic becomes more regular, we should develop more rapid and accurate detection methods to achieve early diagnosis and treatment. Antigen detection methods based on spike protein has great potential, however, it has not been effectively developed, probably due to the torturing conformational complexity. By utilizing cross-blocking data, we clustered SARS-CoV-2 receptor binding domain (RBD)-specific monoclonal antibodies (mAbs) into 6 clusters. Subsequently, the antigenic sites for representative mAbs were identified by RBDs with designed residue substitutions. The sensitivity and specificity of selected antibody pairs was demonstrated using serial diluted samples of SARS-CoV-2 S protein and SARS-CoV S protein. Furthermore, pseudovirus system was constructed to determine the detection capability against SARS-CoV-2 and SARS-CoV. 6 RBD-specific mAbs, recognizing different antigenic sites, were identified as potential candidates for optimal antibody pairs for detection of SARS-CoV-2 S protein. By considering relative spatial position, accessibility and conservation of corresponding antigenic sites, affinity and the presence of competitive antibodies in clinical samples, 6H7-6G3 was rationally identified as optimal antibody pair for detection of both SARS-CoV-2 and SARS-CoV. Furthermore, our results showed that 6H7 and 6G3 effectively bind to SARS-CoV-2 variants of concern (VOCs). Taken together, we identified 6H7-6G3 antibody pair as a promising rapid antigen diagnostic tool in containing COVID-19 pandemic caused by multiple VOCs. Moreover, our results also provide an important reference in screening of antibody pairs detecting antigens with complex conformation.

Case Report: Chronic hepatitis E in a hematopoietic stem cell transplant recipient: The first report of hepatitis E virus genotype 4 causing chronic infection in a non-solid organ recipient

Hepatitis E virus (HEV) is one of the most important public health issues around the world, and chronic HEV infection has been reported in immunosuppressed individuals. This study reported a male case, with very severe aplastic anemia (AA), who developed chronic hepatitis E after hematopoietic stem cell transplantation (HSCT). Abnormal alanine aminotransferase (ALT) appeared after HSCT and persisted for twenty-nine months. The case was seropositive for anti-HEV IgG and IgM after HSCT. Twenty-two months after HSCT, HEV RNA and antigen (Ag) testing were positive and persisted for five and seven months, respectively. Positive stains of HEV Ag were present in a liver biopsy sample. HEV Ag was present in bone marrow. The individual rapidly developed liver cirrhosis and was rescued by a regimen of oral ribavirin. These factors suggested there is a risk of HEV infection in HSCT recipients.

Potential of conserved antigenic sites in development of universal SARS-like coronavirus vaccines

Given pandemic risks of zoonotic SARS-CoV-2 variants and other SARS-like coronaviruses in the future, it is valuable to perform studies on conserved antigenic sites to design universal SARS-like coronavirus vaccines. By using antibodies obtained from convalescent COVID-19 patients, we succeeded in functional comparison of conserved antigenic sites at multiple aspects with each other, and even with SARS-CoV-2 unique antigenic sites, which promotes the cognition of process of humoral immune response to the conserved antigenic sites. The conserved antigenic sites between SARS-CoV-2 and SARS-CoV can effectively induce affinity maturation of cross-binding antibodies, finally resulting in broadly neutralizing antibodies against multiple variants of concern, which provides an important basis for universal vaccine design, however they are subdominant, putatively due to their lower accessibility relative to SARS-CoV-2 unique antigenic sites. Furthermore, we preliminarily design RBDs to improve the immunogenicity of these conserved antigenic sites. Our study focusing on conserved antigenic sites provides insights for promoting the development of universal SARS-like coronavirus vaccines, thereby enhancing our pandemic preparedness.

Urine is a viral antigen reservoir in hepatitis E virus infection

BACKGROUND AND AIMS

HEV ORF2 antigen (Ag) in serum has become a tool for diagnosing current HEV infection. Particularly, urinary shedding of HEV Ag has been gaining increasing interest. We aim to uncover the origin, antigenicity, diagnostic performance, and diagnostic significance of Ag in urine in HEV infection.

APPROACH AND RESULTS

Clinical serum and urine samples from patients with acute and chronic HEV infection were analyzed for their Ag levels. Ag in urine was analyzed by biochemical and proteomic approaches. The origin of urinary Ag and Ag kinetics during HEV infection was investigated in mouse and rabbit models, respectively. We found that both the Ag level and diagnostic sensitivity in urine were higher than in serum. Antigenic protein in urine was an E2s-like dimer spanning amino acids 453-606. pORF2 entered urine from serum in mice i.v. injected with pORF2. Ag in urine originated from the secreted form of pORF2 (ORF2^S ) that abundantly existed in hepatitis E patients' serum. HEV Ag was specifically taken up by renal cells and was disposed into urine, during which the level of Ag was concentrated >10-fold, resulting in the higher diagnosing sensitivity of urine Ag than serum Ag. Moreover, Ag in urine appeared 6 days earlier, lasted longer than viremia and antigenemia, and showed good concordance with fecal RNA in a rabbit model.

CONCLUSIONS

Our findings demonstrated the origin and diagnostic value of urine Ag and provided insights into the disposal of exogenous protein of pathogens by the host kidney.

Identification of a cross-neutralizing antibody that targets the receptor binding site of H1N1 and H5N1 influenza viruses

Influenza A viruses pose a significant threat globally each year, underscoring the need for a vaccine- or antiviral-based broad-protection strategy. Here, we describe a chimeric monoclonal antibody, C12H5, that offers neutralization against seasonal and pandemic H1N1 viruses, and cross-protection against some H5N1 viruses. Notably, C12H5 mAb offers broad neutralizing activity against H1N1 and H5N1 viruses by controlling virus entry and egress, and offers protection against H1N1 and H5N1 viral challenge in vivo. Through structural analyses, we show that C12H5 engages hemagglutinin (HA), the major surface glycoprotein on influenza, at a distinct epitope overlapping the receptor binding site and covering the 140-loop. We identified eight highly conserved (~90%) residues that are essential for broad H1N1 recognition, with evidence of tolerance for Asp or Glu at position 190; this site is a molecular determinant for human or avian host-specific recognition and this tolerance endows C12H5 with cross-neutralization potential. Our results could benefit the development of antiviral drugs and the design of broad-protection influenza vaccines.

Circulating subtypes of Influenza viruses seasonally change and therefore vaccines need to be matched to these strains each year, which is why there is a need for next-generation vaccines that can elicit broad and cross-type protection. Here, Li et al. generate a human-mouse chimeric antibody with broad neutralizing activity against seasonal and pandemic H1N1 and some H5N1 viruses in vivo and identify residues on hemagglutinin relevant for its broad neutralization activity.

Three SARS-CoV-2 antibodies provide broad and synergistic neutralization against variants of concern, including Omicron

The rapidly spreading Omicron variant is highly resistant to vaccines, convalescent sera, and neutralizing antibodies (nAbs), highlighting the urgent need for potent therapeutic nAbs. Here, a panel of human nAbs from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) convalescent patients show diverse neutralization against Omicron, of which XMA01 and XMA04 maintain nanomolar affinities and excellent neutralization (half maximal inhibitory concentration [IC50]: ∼20 ng/mL). nAb XMA09 shows weak but unattenuated neutralization against all variants of concern (VOCs) as well as SARS-CoV. Structural analysis reveals that the above three antibodies could synergistically bind to the receptor-binding domains (RBDs) of both wild-type and Omicron spikes and defines the critical determinants for nAb-mediated broad neutralizations. Three nAbs confer synergistic neutralization against Omicron, resulting from the inter-antibody interaction between XMA04 and XMA01(or XMA09). Furthermore, the XMA01/XMA04 cocktail provides synergistic protection against Beta and Omicron variant infections in hamsters. In summary, our results provide insights for the rational design of antibody cocktail therapeutics or universal vaccines against Omicron.

Quantitative evaluation of protective antibody response induced by hepatitis E vaccine in humans

Efficacy evaluation through human trials is crucial for advancing a vaccine candidate to clinics. Next-generation sequencing (NGS) can be used to quantify B cell repertoire response and trace antibody lineages during vaccination. Here, we demonstrate this application with a case study of Hecolin®, the licensed vaccine for hepatitis E virus (HEV). Four subjects are administered the vaccine following a standard three-dose schedule. Vaccine-induced antibodies exhibit a high degree of clonal diversity, recognize five conformational antigenic sites of the genotype 1 HEV p239 antigen, and cross-react with other genotypes. Unbiased repertoire sequencing is performed for seven time points over six months of vaccination, with maturation pathways characterize for a set of vaccine-induced antibodies. In addition to dynamic repertoire profiles, NGS analysis reveals differential patterns of HEV-specific antibody lineages and highlights the necessity of the long vaccine boost. Together, our study presents a quantitative strategy for vaccine evaluation in small-scale human studies.

Application of Hepatitis E Virus-Related Markers on Samples from a Developing Country

BACKGROUND

Nepal is an endemic area for hepatitis E virus (HEV) epidemics. The research on viral hepatitis in Nepal is limited.

METHODS

Serum samples from 170 patients presenting with symptoms of hepatitis were collected from April to May 2014 in Biratnagar, Nepal, and then transported to Xiamen, China, for further evaluation. All samples were tested for HEV RNA, HEV antigen, anti-HEV IgM, anti-HEV IgG and anti-HBc IgM, anti-HCV IgG, and anti-HAV IgM.

RESULTS

Sixteen patients were identified as acute hepatitis E with the presence of ≥ 2 HEV acute phase markers (antigen, RNA, and anti-HEV IgM). HEV infection was the major cause of potential active viral hepatitis (59.2%, 16 of 27), followed by HBV (25.9%, 7 of 27, anti-HBc IgM positive), HAV (18.5%, 5 of 27, anti-HAV IgM positive), and HCV (3.7%, 1 of 27, anti-HCV antibodies). All 16 confirmed HE cases were positive for HEV antigen, while 5 cases were HEV RNA positive, as well as 15 anti-HEV IgM positive. The low positive rate of RNA might be related to the collection and/or the transportation of these samples.

CONCLUSIONS

This study showed that HEV is a major cause of acute hepatitis in developing countries and regions. Application of immunoassay diagnostic kits, especially the HEV antigen tests, showed great potential for HE detection in these countries and regions.

An Optimized High-Throughput Neutralization Assay for Hepatitis E Virus (HEV) Involving Detection of Secreted Porf2

Hepatitis E virus (HEV) is a common cause of acute hepatitis worldwide. Current methods for evaluating the neutralizing activity of HEV-specific antibodies include immunofluorescence focus assays (IFAs) and real-time PCR, which are insensitive and operationally complicated. Here, we developed a high-throughput neutralization assay by measuring secreted pORF2 levels using an HEV antigen enzyme-linked immunosorbent assay (ELISA) kit based on the highly replicating HEV genotype (gt) 3 strain Kernow. We evaluated the neutralizing activity of HEV-specific antibodies and the sera of vaccinated individuals (n = 15) by traditional IFA and the novel assay simultaneously. A linear regression analysis shows that there is a high degree of correlation between the two assays. Furthermore, the anti-HEV IgG levels exhibited moderate correlation with the neutralizing titers of the sera of vaccinated individuals, indicating that immunization with gt 1 can protect against gt 3 Kernow infection. We then determined specificity of the novel assay and the potential threshold of neutralizing capacity using anti-HEV IgG positive sera (n = 27) and anti-HEV IgG negative sera (n = 23). The neutralizing capacity of anti-HEV IgG positive sera was significantly stronger than that of anti-HEV IgG negative. In addition, ROC curve analysis shows that the potential threshold of neutralizing capacity of sera was 8.07, and the sensitivity and specificity of the novel assay was 88.6% and 100%, respectively. Our results suggest that the neutralization assay using the antigen ELISA kit could be a useful tool for HEV clinical research.

[Analysis of polymorphism of Pfhrp2 gene in Plasmodium falciparum from falciparum malaria patients in Yunnan Province]

OBJECTIVE

To analyze the polymorphism of histidine rich protein 2 (HRP II) gene in Plasmodium falciparum (Pfhrp2) from falciparum malaria patients in Yunnan Province, so as to lay the foundation for studying the defection of antigen genes of Plasmodium.

METHODS

The filter paper blood samples and related information of falciparum malaria cases reported were obtained in Yunnan Province from August 2012 to September 2015. Under the guidance of the specific primers, the exon2 regions in Pfhrp2 gene in P. falciparum from DNA samples were amplified by PCR, and the PCR products were sequenced. The sequences of exon2 region in Pfhrp2 gene were blasted by comparing with the reference sequences AY816237, AY816240, and AY816301. Next, the polymorphism of the sequence in exon2 region of Pfhrp2 gene was analyzed by MEGA 5.04 software. The conserved sites and genetic distances between sequences were calculated by using the software as well, and the clustering tree was drawn according to the genetic distances between the amino acid sequences.

RESULTS

A total of 218 bloods samples from the falciparum malaria cases in 15 prefectures of Yunnan Province were collected, and the sources of infection included Yunnan, Africa and Myanmar. The PCR results showed that the exon2 regions in Pfhrp2 genes of 155 samples were positive by amplification and their products were sequenced successfully. The sequence analysis showed that the length range of the amino acid residues of exon2 region in Pfhrp2 gene was from 115 aa to 298 aa, the average length was 239.7 aa. There was no statistically significance among the means of the amino acid residues of the isolates from Africa (239.9 aa), Myanmar (239.5 aa) and Yunnan (241.6 aa) (F = 0.025, P > 0.05). All the 155 amino acid sequences ended with type 12 repeat, 98.1% (152/155) of them started with type 1 repeat and 1.9% (3/155) of them started with type 2. Type 2 presented most frequently repeat in all the sequences and the average repeat times were 12.9. The homologous locus of the DNA sequences in exon2 regions of the 155 Pfhrp2 genes was 894 bp, among which the conservative sites accounted for 20.6% (186/894), and the variable sites for 78.2% (699/ 894). The genetic distances between the sequences of Africa isolates ranged from 0 to 0.741, and those of the Myanmar and Yunnan isolates were 0-0.948 and 0-0.750, respectively. The cluster analysis showed that all the 155 sequences clustered into 3 categories on genetic distances between amino acid sequences according to the size of the amino acid sequence length. At the same level, the sequences had approximate lengths and amino acid repeat types.

CONCLUSIONS

The sequence of exon2 region in Pfhrp2 gene of P. falciparum from falciparum malaria cases in Yunnan Province is highly polymorphic, the P. falciparum isolates are clustered mainly according to the size of the amino acid sequence of exon2 region in Pfhrp2 gene.

Development and evaluation of a rapid point-of-care test for detecting the hepatitis E virus antigen

BACKGROUND

Hepatitis E virus (HEV)-caused acute viral hepatitis is a major threat to public health worldwide. Recently, an enzyme linked immunosorbent assay (ELISA) kit detecting the HEV antigen was reported to have good concordance with the HEV RNA load and showed good clinical performance. But the ELISA kits can barely satisfy the needs of community clinics. In this study, a fluorescent microbead-based immunoassay (FMIA) for detecting the HEV antigen was developed and evaluated.

METHODS

A mouse anti-HEV monoclonal antibody (mAb) conjugated with fluorescent microbeads was used as capturing antibody and another mouse mAb was used as detection antibody. Overall, 150 serum samples were collected from HEV-infected patients (n = 50) and non-HEV cases (n = 100) to evaluate the performance of the FMIA.

RESULTS

The FMIA results showed a strong linear correlation with the viral RNA load. The diagnostic sensitivity and specificity of the HEV antigen FMIA were 92.0% (46/50) and 100.0% (100/100), respectively, and the test was consistent (kappa = 0.937, p = 0.627) with the commercial HEV antigen ELISA. The FMIA also showed good consistency with the PCR results (kappa = 0.939, p = 0.134).

CONCLUSIONS

As a rapid point-of-care (POC) test, a FMIA that is developed with acceptable performance is suitable for acute hepatitis E diagnosis, especially in developing countries and regions, because of its reduced time and simplified operation.

[Time characteristics of imported malaria cases in Yunnan Province]

Objective To investigate the time distribution characteristics and the epidemic trends of imported malaria cases in Yunnan Province. Methods The malaria case records and epidemiological history data of Yunnan Province were collected, and the local infection cases were excluded. The data were statistical analyzed. Results The imported malaria cases had a significantly seasonal periodicity (Q = 26.574, P < 0.05) and epidemic trends (Q = 35.487, P < 0.05). The imported peak was in May, while February was the lowest month of imported cases, and the difference was significant (Z = -2.619, P < 0.05). The simple seasonal prediction model was the best model (R² = 0.677, BIC = 4.867) for forecast while the residual sequence was white noise (Q = 14.226, P > 0.05). By using the model to predict the cases in January, February and March of 2016, the number (95% CI) were 29 (7-50), 22 (0-44) and 31 (8-54), and the actual number of imported malaria cases were 29, 24 and 38 cases respectively and all cases were included in the 95% CI. Conclusion The imported malaria cases in Yunnan Province had a significantly seasonal periodicity and epidemic trends, and the established model has good prediction on the recent cases.

[Geographical features of malaria in Yunnan Province]

OBJECTIVE

To understand the geographical features of malaria in Yunnan Province, so as to provide the reference for malaria elimination.

METHODS

The data of malaria in Yunnan Province from 2012 to 2015 were collected and analyzed.

RESULTS

Totally 2 586 malaria cases were reported in Yunnan Province from 2012 to 2015, in which 274 (10.60%) were local cases and 2 311 (89.37%) were abroad imported, and one (0.03%) was domestic imported. The imported malaria cases and local cases were analyzed according to the sources and locations respectively, and the arithmetic means of the numbers of imported and local cases were 96.29 and 10.96 respectively, the standard deviations of the numbers of imported and local cases were 421.18 and 19.12 respectively, and the difference of the means was not significant (Z = - 0.326, P > 0.10). Both the imported and local malaria cases could be clustered into five sections by the number of 5. The Herfendal-Hirshman indexes of the imported and local malaria cases were 8 121 and 1 598 respectively.

CONCLUSIONS

There is no significant difference of the distribution between the imported and local malaria cases, and they should be attaching equal importance. The non-uniform degree of imported cases is higher than that of the local cases, while both of them could be divided into five major clusters in the prevention and control work.

A high-throughput neutralizing assay for antibodies and sera against hepatitis E virus

Hepatitis E virus (HEV) is the aetiological agent of enterically transmitted hepatitis. The traditional methods for evaluating neutralizing antibody titres against HEV are real-time PCR and the immunofluorescence foci assay (IFA), which are poorly repeatable and operationally complicated, factors that limit their applicability to high-throughput assays. In this study, we developed a novel high-throughput neutralizing assay based on biotin-conjugated p239 (HEV recombinant capsid proteins, a.a. 368–606) and staining with allophycocyanin-conjugated streptavidin (streptavidin APC) to amplify the fluorescence signal. A linear regression analysis indicated that there was a high degree of correlation between IFA and the novel assay. Using this method, we quantitatively evaluated the neutralization of sera from HEV-infected and vaccinated macaques. The anti-HEV IgG level had good concordance with the neutralizing titres of macaque sera. However, the neutralization titres of the sera were also influenced by anti-HEV IgM responses. Further analysis also indicated that, although vaccination with HEV vaccine stimulated higher anti-HEV IgG and neutralization titres than infection with HEV in macaques, the proportions of neutralizing antibodies in the infected macaques’ sera were higher than in the vaccinated macaques with the same anti-HEV IgG levels. Thus, the infection more efficiently stimulated neutralizing antibody responses.

Differences in the epidemiology and virology of mild, severe and fatal human infections with avian influenza A (H7N9) virus

A novel avian influenza A (H7N9) virus caused 5-10 % mild and 30.5 % fatal human infections as of December 10, 2015. In order to investigate the reason for the higher rate of fatal outcome of this infection, this study compared the molecular epidemiology and virology of avian influenza A (H7N9) viruses from mild (N = 14), severe (N = 50) and fatal (N = 35) cases, as well as from non-human hosts (N = 73). The epidemiological results showed that the average age of the people in the mild, severe and fatal groups was 27.6, 52 and 62 years old, respectively (p < 0.001). Males accounted for 42.9 % (6/14), 58.0 % (29/50), and 74.3 % (26/35) of cases in the mild, severe and fatal group respectively (p = 0.094). Median days from onset to start of antiviral treatment were 2, 5 and 7 days in the mild, severe and fatal group, respectively (p = 0.002). The median time from onset to discharge/death was 12, 40 and 19 days in the mild, severe and fatal group, respectively (p < 0.001). Analysis of whole genome sequences showed that PB2 (E627K), NA (R294K) and PA (V100A) mutations were markedly associated with an increased fatality rate, while HA (N276D) and PB2 (N559T) mutations were clearly related to mild cases. There were no differences in the genotypes, adaptation to mammalian hosts, and genetic identity between the three types of infection. In conclusion, advanced age and delayed confirmation of diagnosis and antiviral intervention were risk factors for death. Furthermore, PB2 (E627K), NA (R294K) and PA (V100A) mutations might contribute to a fatal outcome in human H7N9 infection.

Compound heterozygous mutations in TTC7A cause familial multiple intestinal atresias and severe combined immunodeficiency

Familial multiple intestinal atresias is an autosomal recessive disease with or without combined immunodeficiency. In the last year, several reports have described mutations in the gene TTC7A as causal to the disease in different populations. However, exact correlation between different genotypes and various phenotypes are not clear. In this study, we report identification of novel compound heterozygous mutations in TTC7A gene in a Malay girl with familial multiple intestinal atresias and severe combined immunodeficiency (MIA-SCID) by whole exome sequencing. We found two mutations in TTC7A: one that destroyed a putative splicing acceptor at the junction of intron 17/exon 18 and one that introduced a stop codon that would truncate the last two amino acids of the encoded protein. Reviewing the recent reports on TTC7A mutations reveals correlation between the position and nature of the mutations with patient survival and clinical manifestations. Examination of public databases also suggests carrier status for healthy individuals, making a case for population screening on this gene, especially in populations with suspected frequent founder mutations.

Impact of nursing home residence on hospital epidemiology of meticillin-resistant Staphylococcus aureus: a perspective from Asia

In a Singapore hospital practising meticillin-resistant Staphylococcus aureus (MRSA) admission screening, the relative risk for MRSA colonization for those admitted from nursing homes was 6.89 (95% confidence interval: 5.74-8.26; 41% of 190 vs 6.0% of 14,849). However, the MRSA burden on admission attributable to nursing home residence was low (6.9%). Risk factors independently associated with MRSA colonization in patients admitted from nursing homes were previous hospital admissions, broken skin, prior use of antibiotics and Chinese ethnicity. Low rates of nursing home use means that the overall impact of nursing home residence on MRSA in our hospital is low.

Diffusion-weighted magnetic resonance imaging in patients with known or suspected breast malignancy: Correlation between apparent diffusion coefficient and histopathologic diagnoses

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Background: Magnetic resonance imaging (MRI) is an important imaging modality for evaluating patients at high risk for breast malignancy. However, the role and utility of diffusion-weighted imaging (DWI) in breast MRI has not been fully elucidated. This study was designed to investigate the relationship between apparent diffusion coefficient (ADC) values and histopathologic diagnoses in benign and malignant breast pathologies as well as to assess the relative diagnostic value of this parameter.

Methods: We searched our database for patients who received breast MRI studies from February 2010 through March 2011. We then identified those patients who had either known or suspected breast malignancy and who had also undergone DWI. Breast abnormalities were identified through a review of the short tau inversion recovery (STIR) and T1-weighted pre- and post-contrast images. DWI images were evaluated and the corresponding ADC values were calculated. These lesions were correlated with histopathologic results when available.

Results: A total of 174 patient MRI studies were evaluated. Single dominant lesions were assessed and included biopsy-proven infiltrating ductal carcinoma (IDC), biopsy-proven ductal carcinoma in situ (DCIS), and benign lesions including cysts. The median ADC value for IDC was 118 x 10-5 mm2 s-1. The median ADC value for DCIS was 123 x 10-5 mm2 s-1. Finally, the median ADC value for breast cysts was 217 x 10-5 mm2 s-1.

Conclusions: As the role of MRI continues to evolve in the evaluation of breast pathology, the addition of DWI may increase diagnostic confidence for breast cancer, allowing for further differentiation from benign lesions. DWI is feasible to implement in many clinical practices and correlates with imaging features of breast cancer. The DWI images are acquired rapidly and without intravenous contrast. This method of imaging could be used in short intervals to assess treatment response to therapies such as biologic inhibitors or radiation therapy.

Analysis of Kerr effect in resonator fiber optic gyros with triangular wave phase modulation

We present an in-depth analysis of the Kerr effect in resonator fiber optic gyros (R-FOGs) based on triangular wave phase modulation. Formulations that relate gyro output to the rotation rate, the Kerr nonlinearity, and other fiber and gyro parameters are derived and used to study the effect of Kerr nonlinearity on the gyro performance. Numerical investigation shows that the Kerr effect results in a nonzero gyro output even when the gyro is at stationary, which is interpreted as an error in the measurement of rotation rate. This error was found to increase as the frequencies of the two triangular phase modulations deviate from each other, and is not zero even if the intensities of the two counterpropagating beams are exactly the same. For fixed frequencies of the triangular phase modulations, there exists an optimal intensity splitting ratio for the two counterpropagating beams, which leads to zero gyro error. Calculation shows that the measurement error due to the Kerr effect for an R-FOG with a hollow-core photonic bandgap fiber as the fiber loop can be one to two orders of magnitude smaller than an R-FOG with a conventional single mode fiber loop.

A comprehensive model of allergic rhinitis in guinea pigs

INTRODUCTION

The economic and social impact of allergic rhinitis is substantial. The effectiveness of currently available medications is limited and therefore investigations for more effective drugs is essential. This study was intended to establish a model of allergic rhinitis in guinea pigs that can be utilized for further investigation of new drugs.

METHODS

Male Dunkin Hartley guinea pigs were sensitized intranasally to, and challenged with, ovalbumin. Sneezing (SN) and nose rubbing (NR) response to allergen challenge were observed on day 21 post-initiation of sensitization in conscious guinea pigs. Nasal blockade (NB), leukocyte infiltration, and lung inflation pressure (LIP) were assessed in the same guinea pigs 23-28 days post-initiation of sensitization. A ventilator/flow method was used to measure NB and LIP. Leukocyte infiltration into nasal lavage fluid 60 min after challenge in the same animals was recorded as total and differential cell counts.

RESULTS

Sensitized guinea pigs produced acute allergic responses after allergen challenge. This was characterized by increases in SN, NR, NB, and eosinophil infiltration. In addition, intranasal allergen challenge did not change lung inflation pressure.

DISCUSSION

Allergen-induced rhinitis in guinea pigs resembles that in humans. The model reported in this study can be used to reflect the effectiveness of drugs currently used to treat allergic rhinitis and to investigate new potential drugs for the treatment of allergic rhinitis.

Comparative observation with MRI and pathology of brain edema at the early stage of severe burn

OBJECTIVE

To investigate the correlation between MRI features and pathology in brain edema at the early stage of severe burn (5 0% TBSA III degree) in dogs.

METHODS

Fifty-two dogs were randomized into control, simple b urn (SB), burn plus sodium lactate (BSL), and burn plus glucose solution groups (BGS). The manifestation of the brain of control group was compared with that of burn groups at 6, 12, 18 and 24 hours postburn with MRI and pathological examination (gross appearance, electron microscopy and light microscopy).

RESULTS

The earliest findings of brain edema were seen at 12 h ours after burn in BGS group, in which brain swelling was the main feature of MR I. The decrease of SIR on T(1)WI was not observed until it was exceeded 10%. Sig nal of T(2)WI increased by 8.29% at 24 hours after burn. It was difficult to distinguish the gray matter from the white matter at the boundary line, which became blurred later. Histological changes of brain edema were observed as early as 6 hours after burn, being accompanied by swelling of endothelial cells and peri-vescular astrocytes, and vacuolation took place in neurons at 12 hours after burn, with different degrees of necrosis of capillary endothelium, neurons, and axons. These changes became more marked with elapse of time. The BGS group showed the most obvious changes mentioned above at 24 hours after burn.

CONCLUSIONS

The model of the brain edema after severe burn has the feature of both vasogenic edema and cytotoxic edema on the MRI and pathology. Positive MRI findings lagged behind that of the pathomorphological changes.

[Application of triple-color flow cytometry for minimal residual disease detection in acute B-lymphoblastic leukemia]

OBJECTIVE

To set up a sensitive triple-color flow cytometric assay (FCM) for detection of residual leukemia cells.

METHODS

Application of triple-color flow cytometry to the patients for detecting CD(10)(+)CD(22)(+)CD(45)(- or dim) leukemic cells in acute B lymphoblastic leukemia (B-ALL).

RESULTS

Leukemic cells in B-ALL patients' bone marrow (BM) consistently showed the CD(10)(+)CD(22)(+)CD(45)(- or dim) phenotype. FCM analysis could detect leukemic cells at the level of 1 per 10(4) cells. The CD(10)(+)CD(22)(+)CD(45)(- or dim) cell population was absent in normal BM, regenerating BM, and BM from leukemia patients in continuous complete remission. This assay could identify residual leukemic cells in 50 days after starting induction chemotherapy. Furthermore, a gradual increase of leukemic cell population could be monitored by this assay before morphological confirmation of BM relapse.

CONCLUSION

Triple-color FCM was a sensitive method for detecting BM CD(10)(+)CD(22)(+)CD(45)(minus sign or dim) leukemic cells and could be an additional useful tool to monitor MRD in B-ALL patients.

[A canine model of brain edema established in the early postburn stage]

OBJECTIVE

To establish a canine model of brain edema in the early stage of severe burn.

METHODS

Mongrel dogs were inflicted by napalm with 50% TBSA III degree burn. The dogs were randomized into normal control (C), burn (B), burn with balanced salt solution (S) and burn with glucose (G) groups. The macropathological, histopathological and ultrastructural changes of brain tissue and brain water (%) were examined at 6, 12, 18 and 24 postburn hours (PBH), respectively, with simultaneous evaluation of blood brain barrier by (99) TC -- ECD.

RESULTS

Pathological evidence of brain edema exhibited at as early as 6 PBH in B, S and G groups, which included cellular swelling of partial endothelia and pericapillary astrocytes, and ischemic necrosis of endothelia, neurons and axons to varying degrees. All the changes exhibited more and more obvious with the elapse of postburn time. The brain water content in each burn group, especially in G group at 24 PBH, was more than that in C group. It was indicated by nuclide imaging that there appeared gradual increasing of the concentration of (99) TC -- ECD in brain tissue in B and C groups since 6 PBH.

CONCLUSION

This model was established for the convenience of burn scholars to study the pathogenesis and management of postburn brain edema.

[Cord blood plasma selectively stimulates the expansion of hematopoietic pregenitor cells in vitro]

OBJECTIVE

To explore the effect of cord blood (CB) plasma on the expansion of hematopoietic progenitor cells.

METHODS

The effect of CB plasma on the expansion of CB and bone marrow (BM)-derived hematopoietic progenitor cells was studies and compared with those of adult's peripheral blood (PB) plasma and cytokines such as IL-3 and SCF.

RESULTS

(1) CB plasma increased CFU yields of CB-derived progenitor cells by 2.23 +/- 0.52-fold and this expansion was dependent on CB plasma concentrations supplemented in the cultures. Greater expansion of progenitor cells was found when ABO was unmatched between the CB-derived cells and CB plasma. (2) Stimulating effect of CB plasma on BM-derived progenitor cells was also related to ABO type. CFU yields were increased by 1.55 +/- 0.43-fold when ABO was unmatched and not increased when ABO was matched. (3) Expansion of CB-derived progenitor cells by IL-3 and SCF was revealed. Significant increase in CFU yields occurred in the addition of both the cytokine and the CB plasma. (4) No expansion occurred in CB-and BM-derived cell cultures supplemented with PB plasma.

CONCLUSION

There is factor(s) selectively stimulating expansion of progenitor cells in CB plasma. It may be beneficial that CB plasma was transfused with CB-derived stem cell transplantation.

Psychosis and genes with trinucleotide repeat polymorphism

Abnormal expansion of genes with trinucleotide repeat (TNR) polymorphism has been found in a number of neuropsychiatric disorders. These disorders and the major psychoses, schizophrenia and bipolar affective disorder, appear to share an interesting phenomenon: genetic anticipation. Because TNR expansion correlates with anticipation, these unstable DNA sites are considered important candidate loci for the major psychoses. We investigated genes with TNR polymorphisms, including B1, B33, B37, and the N-cadherin gene, in unrelated Caucasian North American and Italian schizophrenics (n = 53 to 74), and matched controls. Also, unrelated Caucasian North American patients with bipolar I affective disorder were screened for the B33 and N-cadherin genes (n = 49 and 63, respectively). No unusually long alleles that would suggest abnormal expansion of the TNR were observed for any of these genes. Also, no statistically significant results were found in tests for genetic association between any of these genes and schizophrenia. For B37, a trend toward a difference in allele counts between schizophrenics and controls was observed. However, no clear evidence for a role of these TNR-containing genes in schizophrenia or bipolar affective disorders was found.

Collateral circulatory development in skeletal muscle

The arterial collateral anastomoses in rectus abdominis of the dog are employed as an animal model. The dynamic changes of collateral channels have been uncovered during roestablishment of collateral circulation. The experimental results display the 3 morphological characters, calibre dilatation, cell proliferation, and vessel reconstruction, at different time intervals in the collateral development. It provides evidence that some useful programme can be added to get a more effective collateral circulatory function in clinical practice.