Xianfei Ye

Bio: Xianfei Ye is an academic researcher from Zhejiang University. The author has contributed to research in topics: Antigen & Antibody. The author has an hindex of 4, co-authored 4 publications receiving 58 citations.

Benefit of Early Initiation of Neuraminidase Inhibitor Treatment to Hospitalized Patients With Avian Influenza A(H7N9) Virus

Abstract: Background The significance of early neuraminidase inhibitor (NAI) therapy for treating influenza A(H7N9) is currently unknown. Methods The duration of viral shedding was monitored by reverse-transcription polymerase chain reaction after patients with confirmed H7N9 infection were admitted to the First Affiliated Hospital, Zhejiang University, during April 2013-April 2017. Indices such as the length of hospitalization and mortality were collected, and the correlation between the time of administration of NAI and the severity of disease was systematically analyzed. Results One hundred sixty patients with confirmed H7N9 infection were divided into 3 groups according to NAI starting time. Three of 20 (15%) patients for whom NAI was administered within 2 days died compared with 12 of 52 (23.1%) patients who received treatment within 2-5 days and 33 of 88 (37.5%) patients who were treated after 5 days (P < .05). The median durations of viral shedding from NAI therapy initiation was 4.5 days (interquartile range [IQR], 3-9 days) for patients who took antiviral medication within 2 days, which was significantly different from that for patients who took medication within 2-5 days (7.5 days [IQR, 4.25-12.75 days]) or after 5 days (7 days [IQR, 5-10 days]) (P < .05). We found that the duration of viral shedding from NAI therapy was the shortest in spring 2013 (5.5 days) and the longest in winter-spring 2016-2017 (8.5 days) (P < .05), showing a prolonged trend. Conclusions Early NAI therapy within 2 days of illness shortened the duration of viral shedding and improved survival in patients with H7N9 viral infection.

Increased frequency of circulating follicular helper T cells in children with hand, foot, and mouth disease caused by enterovirus 71 infection.

Abstract: Enterovirus 71 (EV71) is a major causative agent of hand, foot, and mouth disease (HFMD) in children. The role of T follicular helper (TFH) cells in EV71-infected children remains unclear in regulating humoral immunity. The frequency of circulating ICOS(high)/PD-1(high)CXCR5(+)CD4(+) TFH cells in the children with mild and severe EV71 infection and healthy controls (HC) was detected by flow cytometry, respectively. IL-21 and IL-6 mRNA expression and their serum levels, Bcl-6 mRNA expression, and specific neutralizing antibodies against EV71 (NAb-EV71) were measured. In the acute stage of patients with EV71 infection, increased frequencies of circulating TFH cells with ICOS(high) and PD-1(high) expression in the mild and severe patients were observed, and the positive correlations among the frequencies of circulating TFH cells and the serum levels of IL-21, IL-6, and NAb-EV71 titres were detected, respectively. Moreover, the expressions of IL-6 and IL-21 mRNA in PBMCs from patients were also significantly higher than those of HC. However, further analysis did not reveal any significant differences between mild and severe patients. These data indicate a role of TFH cells and associated cytokines in modulating the humoral response during the pathogenesis of EV71 infection.

Serology, virulence and molecular characteristics of Vibrio parahaemolyticus isolated from seafood in Zhejiang province.

Abstract: Vibrio parahaemolyticus is a leading foodborne pathogen in southeastern China. In this study, 105 strains of V. parahaemolyticus were isolated from fresh seafood in 2013 and 2014. The serotypes, virulence-associated genes and sequence types (STs) of these strains were analyzed. 26 defined serotypes were identified and 69 strains (65.7%) had untypeable O or K antigen. 8 strains (7.6%) had the virulence-associated gene tdh and no strain carried the trh gene. 45.7% (48/105) of isolates contained all four T3SS1 genes and 50% (4/8) tdh+ trh- V. parahaemolyticus isolates lacked at least one of the four tested T3SS2α genes. 105 strains could be categorized into 84 STs and only 3 STs (ST3, ST8, ST675) had appeared in clinical strains. V. parahaemolyticus strains from seafood have more diverse and untypeable serotypes, less virulence-associated genes and more STs than strains from clinical sources.

Factors Associated With Prolonged Viral Shedding in Patients With Avian Influenza A(H7N9) Virus Infection

Abstract: Background Data are limited on the impact of neuraminidase inhibitor (NAI) treatment on avian influenza A(H7N9) virus RNA shedding. Methods In this multicenter, retrospective study, data were collected from adults hospitalized with A(H7N9) infection during 2013-2017 in China. We compared clinical features and A(H7N9) shedding among patients with different NAI doses and combination therapies and evaluated factors associated with A(H7N9) shedding, using Cox proportional hazards regression. Results Among 478 patients, the median age was 56 years, 71% were male, and 37% died. The median time from illness onset to NAI treatment initiation was 8 days (interquartile range [IQR], 6-10 days), and the median duration of A(H7N9) RNA detection from onset was 15.5 days (IQR, 12-20 days). A(H7N9) RNA shedding was shorter in survivors than in patients who died (P < .001). Corticosteroid administration (hazard ratio [HR], 0.62 [95% confidence interval {CI}, .50-.77]) and delayed NAI treatment (HR, 0.90 [95% CI, .91-.96]) were independent risk factors for prolonged A(H7N9) shedding. There was no significant difference in A(H7N9) shedding duration between NAI combination treatment and monotherapy (P = .65) or between standard-dose and double-dose oseltamivir treatment (P = .70). Conclusions Corticosteroid therapy and delayed NAI treatment were associated with prolonged A(H7N9) RNA shedding. NAI combination therapy and double-dose oseltamivir treatment were not associated with a reduced A(H7N9) shedding duration as compared to standard-dose oseltamivir.

The Significance of Mesophilic Aeromonas spp. in Minimally Processed Ready-to-Eat Seafood

Abstract: Minimally processed and ready-to-eat (RTE) seafood products are gaining popularity because of their availability in retail stores and the consumers’ perception of convenience. Products that are subjected to mild processing and products that do not require additional heating prior to consumption are eaten by an increasing proportion of the population, including people that are more susceptible to foodborne disease. Worldwide, seafood is an important source of foodborne outbreaks, but the exact burden is not known. The increased interest in seafood products for raw consumption introduces new food safety issues that must be addressed by all actors in the food chain. Bacteria belonging to genus Aeromonas are ubiquitous in marine environments, and Aeromonas spp. has held the title “emerging foodborne pathogen” for more than a decade. Given its high prevalence in seafood and in vegetables included in many RTE seafood meals, the significance of Aeromonas as a potential foodborne pathogen and a food spoilage organism increases. Some Aeromonas spp. can grow relatively uninhibited in food during refrigeration under a broad range of pH and NaCl concentrations, and in various packaging atmospheres. Strains of several Aeromonas species have shown spoilage potential by the production of spoilage associated metabolites in various seafood products, but the knowledge on spoilage in cold water fish species is scarce. The question about the significance of Aeromonas spp. in RTE seafood products is challenged by the limited knowledge on how to identify the truly virulent strains. The limited information on clinically relevant strains is partly due to few registered outbreaks, and to the disputed role as a true foodborne pathogen. However, it is likely that illness caused by Aeromonas might go on undetected due to unreported cases and a lack of adequate identification schemes. A rather confusing taxonomy and inadequate biochemical tests for species identification has led to a biased focus towards some Aeromonas species. Over the last ten years, several housekeeping genes has replaced the 16S rRNA gene as suitable genetic markers for phylogenetic analysis. The result is a more clear and robust taxonomy and updated knowledge on the currently circulating environmental strains. Nevertheless, more knowledge on which factors that contribute to virulence and how to control the potential pathogenic strains of Aeromonas in perishable RTE seafood products are needed.

Circulating serum HBsAg level is a biomarker for HBV-specific T and B cell responses in chronic hepatitis B patients

Abstract: Chronic hepatitis B (CHB) infection functional cure is defined as sustained loss of HBsAg and several therapeutic strategies are in clinical development designed to pharmacologically reduce serum HBsAg, break immune tolerance, and increase functional cure rates. However, little is known about pre-treatment HBsAg levels as an indicator of HBV immune potential. Here, we compared the phenotypes and HBV-specific response of lymphocytes in CHB patients stratified by serum HBsAg levels 50,000 IU/ml (HBshi) using immunological assays (flow cytometry, ICS, ELISPOT). HBshi patients had significantly higher expression of inhibitory PD-1 on CD4+ T cells, particularly among TEMRA subset, and higher FcRL5 expression on B cells. Upon HBcAg(core) or HBsAg(env)-stimulation, 85% and 60% of HBslo patients had IFNγ+TNFα+ and IFNγ+ IL2+ CD4+ T cell responses respectively, in comparison to 33% and 13% of HBshi patients. Checkpoint blockade with αPD-1 improved HBV-specific CD4+ T cell function only in HBslo patients. HBsAg-specific antibody-secreting cells (ASCs) response was not different between these groups, yet αPD-1 treatment resulted in significantly higher fold change in ASCs among patients with HBsAg 5,000 IU/ml. Thus, serum HBsAg correlates with inhibitory receptor expression, HBV-specific CD4+ T cell responses, and augmentation by checkpoint blockade.

Neutrophil-lymphocyte ratio as an early new marker in AIV-H7N9-infected patients: a retrospective study.

Abstract: Background: Avian AIV-H7N9 influenza progresses rapidly and has a high fatality rate. However, it lacks an early effective biomarker to predict disease severity and fatal outcomes successfully. Our study aimed to explore whether the neutrophil-to-lymphocyte ratio (NLR) taken within 24 h after admission can predict disease severity and fatality in AIV-H7N9-infected patients. Methods: We retrospectively studied 237 AIV-H7N9-infected patients from multiple centers from 2013 to 2015. We used univariate analysis and multivariate analysis to compare clinical variables between the survival and fatal groups to evaluate the prognostic value. Results: The NLR taken within 24 h after admission in the fatal group was significantly higher than that in the survival group (P<0.01). Our study found that NLR was independently associated with fatality. The area under the curve (AUC) of the NLR was 0.70, and moreover, when the NLR =19.94, the specificity was 100%, and the sensitivity was 28.4%. The fatality in the NLR ≥19.94 group was significantly increased relative to the patients with an NLR <19.94 (P<0.05). Conclusion: The NLR is potentially a predictive prognostic biomarker in patients infected with the AIV-H7N9 influenza virus.