Activation of the NLRP3 inflammasome by human adenovirus type 7 L4 100-kilodalton protein.

Human adenovirus type 7 (HAdV-7) is a significant viral pathogen that causes respiratory infections in children. Currently, there are no specific antiviral drugs or vaccines for children targeting HAdV-7, and the mechanisms of its pathogenesis remain unclear. The NLRP3 inflammasome-driven inflammatory cascade plays a crucial role in the host's antiviral immunity. Our previous study demonstrated that HAdV-7 infection activates the NLRP3 inflammasome. Building upon this finding, our current study has identified the L4 100 kDa protein encoded by HAdV-7 as the primary viral component responsible for NLRP3 inflammasome activation. By utilizing techniques such as co-immunoprecipitation, we have confirmed that the 100 kDa protein interacts with the NLRP3 protein and facilitates the assembly of the NLRP3 inflammasome by binding specifically to the NACHT and LRR domains of NLRP3. These insights offer a deeper understanding of HAdV-7 pathogenesis and contribute to the development of novel antiviral therapies.

Clinical epidemiology of adenovirus pneumonia among Chinese hospitalized children.

Adenovirus pneumonia is a prevalent form of community-acquired pneumonia among children. Research on the epidemiology and economic burden of this disease is crucial for public health, yet comprehensive data remains scarce, making it crucial to highlight on this topic. In this study, the data were extracted from the face sheet of discharge medical records collected from 26 tertiary children's hospitals from January 2016 to December 2021. In total, 1854 children with laboratory-confirmed adenovirus pneumonia were hospitalized, accounting for 0.13% of the total number of hospitalized for pneumonia in the database during the period. In addition, this figure represents a meager 0.027% when compared to the total number of hospitalized children. The male-to-female ratio was 1.78:1. The 1-3-year age group had the highest number of inpatients for adenoviral pneumonia and the largest proportion of the total hospitalizations in the same age group. Overall, winter is the primary season for the prevalence of adenovirus pneumonia, however, in southern China, there are two peak seasons, winter and summer. Although patients with 3/4 adenovirus pneumonia had no significant complications, some patients had complications such as respiratory failure, diarrhea, and myocardial damage. The median length of stay of adenovirus pneumonia was 8 d [interquartile range (IQR) 6-11], and the median hospitalization cost was 1293.83 United States dollars (IQR 811.81-2472.51). These valuable epidemiological insights into adenovirus pneumonia in Chinese children can help direct the development of targeted prevention and control strategies and surveillance measures for HAdV infections in this demographic.

Expert consensus on the diagnosis, treatment, and prevention of respiratory syncytial virus infections in children.

BACKGROUND: Respiratory syncytial virus (RSV) is the leading global cause of respiratory infections and is responsible for about 3 million hospitalizations and more than 100,000 deaths annually in children younger than 5 years, representing a major global healthcare burden. There is a great unmet need for new agents and universal strategies to prevent RSV infections in early life. A multidisciplinary consensus development group comprising experts in epidemiology, infectious diseases, respiratory medicine, and methodology aims to develop the current consensus to address clinical issues of RSV infections in children. DATA SOURCES: The evidence searches and reviews were conducted using electronic databases, including PubMed, Embase, Web of Science, and the Cochrane Library, using variations in terms for "respiratory syncytial virus", "RSV", "lower respiratory tract infection", "bronchiolitis", "acute", "viral pneumonia", "neonatal", "infant" "children", and "pediatric". RESULTS: Evidence-based recommendations regarding diagnosis, treatment, and prevention were proposed with a high degree of consensus. Although supportive care remains the cornerstone for the management of RSV infections, new monoclonal antibodies, vaccines, drug therapies, and viral surveillance techniques are being rolled out. CONCLUSIONS: This consensus, based on international and national scientific evidence, reinforces the current recommendations and integrates the recent advances for optimal care and prevention of RSV infections. Further improvements in the management of RSV infections will require generating the highest quality of evidence through rigorously designed studies that possess little bias and sufficient capacity to identify clinically meaningful end points.

Development and evaluation of a multiplex digital PCR method for sensitive and accurate detection of respiratory pathogens in children.

The emergence of multiplex digital polymerase chain reaction (dPCR) and other detection technologies for respiratory pathogens in recent years has facilitated greater understanding of respiratory virus epidemics. In this study, a multiplex dPCR method was developed and evaluated as a means of detecting five respiratory pathogens in children with acute lower respiratory tract infection (ALRTI). With 139 nasopharyngeal swabs collected from children with ALRTI, pathogens were detected using dPCR and quantitative real-time PCR (qPCR) methods. Of those specimens, dPCR detected 86 positive cases, while qPCR identified 84. Moreover, dPCR exhibited higher sensitivity than qPCR, and displayed no cross-reactivity with common respiratory pathogens. These findings suggest that dPCR-based method could become one of the most promising options for acute respiratory pathogen detection.

Clinical epidemiology and disease burden of adenoviral encephalitis in hospitalized children in China: A nationwide cross-sectional study.

Importance: Adenovirus encephalitis is a significant infectious disease of the central nervous system that commonly affects children under the age of 5 and has a profound impact on the health of infants and young children throughout China. National multicenter epidemiological studies have significant public health implications. Objective: This study aims to report the epidemiology of adenovirus encephalitis in hospitalized children in China, providing valuable guidance for clinicians. Methods: The data utilized in this study were extracted from the comprehensive Futang Update Medical Records database, which comprises discharge medical records collected by 27 tertiary children's hospitals between January 2016 and December 2018 in China. Specifically, the face sheet of discharge medical records encompassed critical sociodemographic variables and basic medical care details. Results: In this database, a total of 544 children were hospitalized due to adenoviral encephalitis. The male-to-female ratio was 1.62:1, with more boys being affected across different age groups and places of residence. Of the children hospitalized, the highest number of hospitalizations occurred in the 1-3-year age group and the number of hospitalizations decreased each year from 2016 to 2018. The disease exhibits seasonal characteristics with a pronounced peak in the summer months of June and July. While most children (58%) did not have any significant complications, one-third of them developed respiratory complications, including pneumonia and acute bronchitis. The median length of stay for adenoviral encephalitis was 7 days, and the median cost of hospitalization was 2145.56 US dollars. Interpretation: This study highlights the prevalence of adenovirus encephalitis in hospitalized children in China. Children aged 1-3 years were found to be the main demographic hospitalized due to this condition, with boys being significantly more affected than girls. The seasonal variations of adenovirus encephalitis were also found to be significant. Fortunately, the fatality rate associated with this condition was low, and the prognosis was generally favorable.

A fatal case of neonatal viral sepsis caused by human parainfluenza virus type 3.

BACKGROUND: Sepsis is a systemic inflammatory response syndrome caused by severe infection in children, but cases of sepsis associated with human parainfluenza virus (HPIV) have been rarely reported in newborns. CASE PRESENTATION: We report a case of HPIV-3 positive full-term newborn admitted to the Neonatal Intensive Care Unit of Beijing Children's Hospital due to hematuria, gloomy spirit, inactivity and loss of appetite for 6 h. He had septic shock when he arrived the Accident & Emergency Department requiring immediate intubation and mechanical ventilation. Intravenous antibiotics were started. He had completely negative response to all anti-shock treatments including fluid resuscitation and vasopressor supports, and died 14 h later. Viral nucleic acid detection and metagenomic next-generation sequencing (mNGS) analyses of nasopharyngeal aspirate and blood specimens verified an HPIV-3 infection, with negative bacterial culture results. The HPIV-3 strain detected in this patient was subtyped as HPIV C3a, and two unreported amino acid mutations were found in the HN protein region. CONCLUSION: The patient had a severe infection associated with HPIV-3, which was the cause of sepsis and septic shock. This study showed the diagnostic value of mNGS in etiological diagnosis, especially in severe neonatal case.

Multicenter analysis of epidemiological and clinical features of pediatric acute lower respiratory tract infections associated with common human coronaviruses in China, 2014-2019.

The common human coronaviruses (HCoVs) HCoV-229E, HCoV-OC43, HCoV-NL63, and HCoV-HKU1 which are members of the coronavirus family are long co-existed with humans and widely distributed globally. Common HCoVs usually cause mild, self-limited upper respiratory tract infections (URTI), and also associated with lower respiratory tract infections (LRTI), especially in children. However, there are little multicentre studies have been conducted in children of several different areas in China, and the epidemic potential of common HCoVs remains unclear. Understanding of the common HCoVs is valuable for clinical and public health. Herein, we retrospectively analysed the medical records of children with acute lower respiratory tract infection admitted to 9 hospitals from different regions in China from 2014 to 2019. Of the 124 patients who tested positive for coronaviruses, OC43 was the predominant type, accounting for 36.3% (45/124) of the detections. Children aged ≤ 6 months and 12-23 months had the highest detection rate of common HCoVs, and the detection rate gradually declined after 2 years old. These four HCoVs could be detected all year round. Among the areas of our study, the overall positive rate was higher in southern China, especially in Guangzhou (29/124, 23.4%). Moreover, common HCoV-positive patients were codetected with 9 other common respiratory pathogens. 229E (11/13, 84.6%) was the most frequently associated with codetection, with EV/RhV was the most frequently codetected virus. Cough (113/124, 91.1%) and fever (73/124, 58.9%) were the most common symptoms of common HCoVs infection.

A sensitive mass spectrometry-based method to identify common respiratory pathogens in children.

Public health threats posed by emerging respiratory infections are a significant concern, particularly in children and infants. Traditional culture-based detection methods are time-consuming and typically require 1-3 days. Herein, we developed and evaluated a 23-plex common respiratory pathogen mass spectrometry assay that enables the simultaneous detection of 18 common respiratory pathogens in children. This assay combines matrix-assisted laser desorption/ionization time of flight mass spectrometry with multiplex reverse transcription-PCR and targets 11 bacterial and 7 viral pathogens (including 10 subtypes), and two internal controls. The detection limit of the common respiratory pathogen mass spectrometry assay was as low as 1 copy/µL, with no cross-reactivity with other organisms. We assessed the clinical performance of the common respiratory pathogen mass spectrometry assay using respiratory samples from 450 children. The total 450 clinical specimens underwent analysis via matrix-assisted laser desorption/ionization time of flight mass spectrometry, and the outcomes were juxtaposed with those derived from real-time reverse-transcriptase PCR conducted concurrently. The concordance between these methods was 96.0%, and the multiple infection identification rate was 7.1%. This innovative approach enables the simultaneous analysis of numerous outcomes from a solitary examination across 192 specimens within a timeframe of approximately 7 hours, with a dramatically reduced sample use and cost. In summary, the common respiratory pathogen mass spectrometry assay is a sensitive, accurate, and cost-effective method for detecting common respiratory pathogens in children and has the potential to revolutionize the diagnosis of respiratory tract infections. IMPORTANCE This study aimed to present and evaluate a novel co-detection method that enables the simultaneous identification of 11 bacterial and 7 viral pathogens in about 7 hours using matrix-assisted laser desorption/ionization time of flight mass spectrometry. Our approach utilizes a combination of multiplex reverse transcription-PCR and matrix-assisted laser desorption/ionization time of flight mass spectrometry, which overcomes the limitations of conventional assays, which include a long assessment time, technical difficulty, and high costs. As a screening method for common respiratory pathogens in children, common respiratory pathogen mass spectrometry assay has the potential to revolutionize the diagnosis of respiratory tract infections by providing an accurate etiological diagnosis. The common respiratory pathogen mass spectrometry assay is expected to be a critical tool for the diagnosis of respiratory infections in children, offering a more efficient, cost-effective, and accurate approach for the detection of common respiratory pathogens.

Autophagy induced by human adenovirus B7 structural protein VI inhibits viral replication.

Human adenovirus B7 (HAdV-B7) causes severe acute lower respiratory tract infections in children. However, neither the child-specific antivirals or vaccines are available, nor the pathogenesis is clear. Autophagy, as part of innate immunity, plays an important role in resistance to viral infection by degrading the virus and promoting the development of innate and adaptive immunity. This study provided evidence that HAdV-B7 infection induced complete autophagic flux, and the pharmacological induction of autophagy decreased HAdV-B7 replication. In this process, the host protein Bcl2-associated athanogene 3 (BAG3) mediated autophagy to inhibit the replication of HAdV-B7 by binding to the PPSY structural domain of viral protein pVI through its WW structural domain. These findings further our understanding of the host immune response during viral infection and will help to develop broad anti-HAdV therapies.

Cross-reactive antibodies against monkeypox virus exist in the population immunized with vaccinia Tian Tan strain in China.

Monkeypox virus (MPXV) belongs to the Orthopoxvirus genus. The worldwide outbreak of MPXV in 2022 has caused widespread concerns. Cross-reactive antibodies induced by vaccinia-inoculation can provide protection against reinfection by MPXV. The vaccinia Tian Tan (VTT) strain, which was widely inoculated in the Chinese population before the 1980s, has genomic differences from other vaccinia strains, although they all belong to the orthopoxviruses family. The current seroprevalence of VTT-vaccinated populations remains unclear more than four decades after the termination of vaccination campaigns in China. Our results showed that cross-reactive IgG antibodies against MPXV were present in 31.8% (75/236) of vaccinees four decades after VTT-vaccination, suggesting that vaccination with VTT may provide long-term protection against MPXV infection in some individuals.

Clinical and molecular epidemiologic features of enterovirus D68 infection in children with acute lower respiratory tract infection in China.

Acute flaccid paralysis (AFP) associated with enterovirus D68 (EV-D68) infection has attracted much attention since an outbreak in the USA in 2014. Notably, EV-D68 was detected in a child with AFP for the first time in China in 2018. In a multicentre study from May 2017 to December 2019, we monitored EV-D68 infections in hospitalized children with acute lower respiratory tract infection (ALRTI) in China. Out of 3,071 samples collected from patients with ALRTI, ten were positive for EV-D68. All patients presented with mild diseases with no neurological symptoms or signs. Phylogenetic analysis based on the VP1 gene showed that all EV-D68 sequences obtained in this study belonged to subclade B3 and were close to sequences of EV-D68 strains obtained from patients with AFP in the USA. Four EV-D68 strains were isolated, and their complete genome sequences were determined. These sequences did not show any evidence of recombination events. To assess their neurotropism, the isolates were used to infect the "neuronal-like" cell line SH-SY5Y, and resulted in a cytopathic effect. We further analysed the structure and sites that may be associated with neurovirulence, including the stem-loop structure in the untranslated region (3'UTR) and identified amino acid substitutions (M291T, V341A, T860N, D927N, S1108G, and R2005K) in the coding region and specific nucleotides (127T, 262C, and 339T) in the 5' UTR. In conclusion, EV-D68 infection was detected in a small number of children with ALRTI in China from 2017 to 2019. Disease symptoms in these children were relatively mild with no neurological complications, and all EV-D68 sequences belonged to subclade B3.

T cell-mediated immunity during Epstein-Barr virus infections in children.

Epstein-Barr virus (EBV) infection is extremely common worldwide, with approximately 90% of adults testing positive for EBV antibodies. Human are susceptible to EBV infection, and primary EBV infection typically occurs early in life. EBV infection can cause infectious mononucleosis (IM) as well as some severe non-neoplastic diseases, such as chronic active EBV infection (CAEBV) and EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH), which can have a heavy disease burden. After primary EBV infection, individuals develop robust EBV-specific T cell immune responses, with EBV-specific CD8+ and part of CD4+ T cells functioning as cytotoxic T cells, defending against virus. Different proteins expressed during EBV's lytic replication and latent proliferation can cause varying degrees of cellular immune responses. Strong T cell immunity plays a key role in controlling infection by decreasing viral load and eliminating infected cells. However, the virus persists as latent infection in EBV healthy carriers even with robust T cell immune response. When reactivated, it undergoes lytic replication and then transmits virions to a new host. Currently, the relationship between the pathogenesis of lymphoproliferative diseases and the adaptive immune system is still not fully clarified and needs to be explored in the future. Investigating the T cell immune responses evoked by EBV and utilizing this knowledge to design promising prophylactic vaccines are urgent issues for future research due to the importance of T cell immunity.

Metatranscriptome Reveals Specific Immune and Microbial Signatures of Respiratory Syncytial Virus Infection in Children.

Respiratory syncytial virus (RSV) is the most frequently detected respiratory virus in children with acute lower respiratory tract infection. Previous transcriptome studies have focused on systemic transcriptional profiles in blood and have not compared the expression of multiple viral transcriptomes. Here, we sought to compare transcriptome responses to infection with four common respiratory viruses for children (respiratory syncytial virus, adenovirus, influenza virus, and human metapneumovirus) in respiratory samples. Transcriptomic analysis showed that cilium organization and assembly were common pathways related to viral infection. Compared with other virus infections, collagen generation pathways were distinctively enriched in RSV infection. We identified two interferon-stimulated genes (ISGs), CXCL11 and IDO1, which were upregulated to a greater extent in the RSV group. In addition, a deconvolution algorithm was used to analyze the composition of immune cells in respiratory tract samples. The proportions of dendritic cells and neutrophils in the RSV group were significantly higher than those in the other virus groups. The RSV group exhibited a higher richness of Streptococcus than the other virus groups. The concordant and discordant responses mapped out here provide a window to explore the pathophysiology of the host response to RSV. Last, according to host-microbe network interference, RSV may disrupt respiratory microbial composition by changing the immune microenvironment. IMPORTANCE In the present study, we demonstrated the comparative results of host responses to infection between RSV and other three common respiratory viruses for children. The comparative transcriptomics study of respiratory samples sheds light on the significant roles that ciliary organization and assembly, extracellular matrix changes, and microbial interactions play in the pathogenesis of RSV infection. Additionally, it was demonstrated that the recruitment of neutrophils and dendritic cells (DCs) in the respiratory tract is more substantial in RSV infection than in other viral infections. Finally, we discovered that RSV infection dramatically increased the expression of two ISGs (CXCL11 and IDO1) and the abundance of Streptococcus.

Clinical epidemiology and disease burden of bronchiolitis in hospitalized children in China: a national cross-sectional study.

BACKGROUND: Bronchiolitis is a common acute lower respiratory tract infection (ALRTI) and the most frequent cause of hospitalization of infants and young children with ALRTI. Respiratory syncytial virus is the main pathogen that leads to severe bronchiolitis. The disease burden is relatively high. To date, few descriptions of the clinical epidemiology and disease burden of children hospitalized for bronchiolitis are available. This study reports the general clinical epidemiological characteristics and disease burden of bronchiolitis in hospitalized children in China. METHODS: This study included the face sheet of discharge medical records collected from 27 tertiary children's hospitals from January 2016 to December 2020 that were aggregated into the FUTang Update medical REcords (FUTURE) database. The sociodemographic variables, length of stay (LOS) and disease burden of children with bronchiolitis were analyzed and compared using appropriate statistical tests. RESULTS: In total, 42,928 children aged 0-3 years were hospitalized due to bronchiolitis from January 2016 to December 2020, accounting for 1.5% of the total number of hospitalized children of the same age in the database during the period and 5.31% of the hospitalizations for ALRTI. The male to female ratio was 2.01:1. Meanwhile, more boys than girls were observed in different regions, age groups, years, and residences. The 1-2 year age group had the greatest number of hospitalizations for bronchiolitis, while the 29 days-6 months group had the largest proportion of the total inpatients and inpatients with ALRTI in the same age group. In terms of region, the hospitalization rate of bronchiolitis was the highest in East China. Overall, the number of hospitalizations from 2017 to 2020 showed a decreasing trend from that in 2016. Seasonally, the peak hospitalizations for bronchiolitis occurred in winter. Hospitalization rates in North China in autumn and winter were higher than those in South China, while hospitalization rates in South China were higher in spring and summer. Approximately, half of the patients with bronchiolitis had no complications. Among the complications, myocardial injury, abnormal liver function and diarrhea were more common. The median LOS was 6 days [interquartile range (IQR) = 5-8], and the median hospitalization cost was 758 United States dollars (IQR = 601.96-1029.53). CONCLUSIONS: Bronchiolitis is a common respiratory disease in infants and young children in China, and it accounts for a higher proportion of both total hospitalizations and hospitalizations due to ALRTI in children. Among them, children aged 29 days-2 years are the main hospitalized population, and the hospitalization rate of boys is significantly higher than that of girls. The peak season for bronchiolitis is winter. Bronchiolitis causes few complications and has a low mortality rate, but the burden of this disease is heavy.

Standardization of Transfer across Labs between Flow Cytometers for Detection of Lymphocytes in Japanese Encephalitis Vaccinated Children.

An increasing number of laboratories need to collect data from multiple flow cytometers, especially for research projects performed across multiple centers. The challenges of using two flow cytometers in different labs include the lack of standardized materials, software compatibility issues, inconsistencies in instrument setup, and the use of different configurations for different flow cytometers. To establish a standardized flow cytometry experiment to achieve the consistency and comparability of experimental results across multiple centers, a rapid and feasible standardization method was established to transfer parameters across different flow cytometers. The methods developed in this study allowed the transfer of experimental settings and analysis templates between two flow cytometers in different laboratories for the detection of lymphocytes in Japanese encephalitis (JE)-vaccinated children. A consistent fluorescence intensity was obtained between the two cytometers using fluorescence standard beads to establish the cytometer settings. Comparable results were obtained in two laboratories with different types of instruments. Using this method, we can standardize analysis for evaluating the immune function of JE-vaccinated children in different laboratories with different instruments, diminish the differences in data and results among flow cytometers in multiple centers, and provide a feasible approach for the mutual accreditation of laboratory results. The standardization method of flow cytometer experiments will ensure the effective performance of research projects across multiple centers.

A multicentre study on the incidence of respiratory viruses in children with community-acquired pneumonia requiring hospitalization in the setting of the zero-COVID policy in China.

BACKGROUND: Stringent nonpharmaceutical interventions (NPIs) have been implemented worldwide to combat the COVID-19 pandemic, and the circulation and seasonality of common respiratory viruses have subsequently changed. There have been few multicentre studies or comparisons of the prevalence of respiratory viruses accounting for community-acquired pneumonia (CAP) in hospitalized children between the pre-COVID period and the period after community and school reopening in the setting of the zero-COVID policy. METHODS: We included 1543 children with CAP who required hospitalization from November 1, 2020 to April 30, 2021 (period 1), and 629 children with the same conditions from November 1, 2018, to April 30, 2019 (period 2), in our study. All respiratory samples from these patients were screened for six respiratory viruses (respiratory syncytial virus [RSV], adenovirus [ADV], influenza A virus [Flu A], influenza B virus [Flu B], parainfluenza virus type 1 [PIV1], and parainfluenza virus type 3 [PIV3]) using a multiplex real-time PCR assay. RESULTS AND CONCLUSIONS: The median ages of the enrolled patients at the time of diagnosis were 1.5 years and 1.0 years for period 1 and period 2, respectively. In period 1, viral pathogens were detected in 50.3% (776/1543) of the enrolled patients. The most frequently identified viral pathogen was RSV (35.9%, 554/1543), followed by PIV3 (9.6%, 148/1543), PIV1 (3.6%, 56/1543), ADV (3.4%, 52/1543), Flu A (1.0%, 16/1543), and Flu B (0.8%, 13/1543). The total detection rates of these six viruses in the peak season of CAP were at the pre-COVID level. The prevalence of Flu A decreased dramatically, and circulation activity was low compared to pre-COVID levels, while the incidence of PIV3 increased significantly. There were no significant differences in the detection rates of RSV, ADV, Flu B, and PIV1 between the two periods. Our results showed that respiratory viruses accounted for CAP in hospitalized children at pre-COVID levels as communities and schools reopened within the zero-COVID policy, although the prevalence aetiology spectrum varied.