A novel variant in a Chinese boy with lysinuric protein intolerance: A case report and literature review.

We report a case of a 4-year-old boy with lysinuric protein intolerance in China. The patient presented with interstitial lung disease with obvious clubbing of the fingers and toes. During the course of diagnosis and treatment, we found he was averse to a high-protein diet, intolerant to activity, and had a history of diarrhea and fractures. Physical examination revealed hepatosplenomegaly and clubbing of the fingers and toes. Next-generation sequencing revealed compound heterozygous mutations (c.1387delG, c.958T > C) in SLC7A7, which was confirmed as a disease-causing gene for lysinuric protein intolerance. After a literature review, we found that c.958T > C had not been previously reported, and summarized the clinical and genetic characteristics of patients from different continents. His symptoms improved significantly after 3 months of being on a low-protein diet, supplementation with lysine, citrulline, carnitine, and trace elements, and oral corticosteroid treatment for 2 months. The patient is still under follow-up.

An injectable and photocurable methacrylate-silk fibroin/nano-hydroxyapatite hydrogel for bone regeneration through osteoimmunomodulation.

Tissue engineering has emerged as a promising approach for addressing bone defects. Most of the traditional 3D printing materials predominantly relying on polymers and ceramics. Although these materials exhibit superior osteogenic effects, their gradual degradation poses a limitation. Digital light processing (DLP) 3D bioprinting that uses natural biomaterials as bioinks has become one of the promising strategies for bone regeneration. In this study, we introduce a hydrogel biomaterial derived from silk fibroin (SF). Notably, we present the novel integration of nano-hydroxyapatite (nHA) into the hydrogel, forming a composite hydrogel that rapidly cross-links upon initiation. Moreover, we demonstrate the loading of nHA through non-covalent bonds in SilMA. In vitro experiments reveal that composite hydrogel scaffolds with 10 % nHA exhibit enhanced osteogenic effects. Transcriptomic analysis indicates that the composite hydrogel promotes bone regeneration by inducing M2 macrophage polarization. Furthermore, rat femoral defect experiments validate the efficacy of SilMA/nHA10 in bone regeneration. This study synthesis of a simple and effective composite hydrogel bioink for bone regeneration, presenting a novel strategy for the future implementation of digital 3D printing technology in bone tissue engineering.

FUNDC1-induced mitophagy protects spinal cord neurons against ischemic injury.

Local ischemia and hypoxia are the most important pathological processes in the early phase of secondary spinal cord injury (SCI), in which mitochondria are the main target of ischemic injury. Mitochondrial autophagy, also known as mitophagy, acts as a selective autophagy that specifically identifies and degrades damaged mitochondria, thereby reducing mitochondria-dependent apoptosis. Accumulating evidence shows that the mitophagy receptor, FUN14 domain-containing 1 (FUNDC1), plays an important role in ischemic injury, but the role of FUNDC1 in SCI has not been reported. In this study, we aimed to investigate whether FUNDC1 can enhance mitophagy and inhibit neuronal apoptosis in the early stage of SCI. In a rat SCI model, we found that FUNDC1 overexpression enhanced neuronal autophagy and decreased neuronal apoptosis in the early stage of injury, thereby reducing spinal cord damage. In vitro studies showed that the neuroprotective effects of FUNDC1 were achieved by inhibiting mitochondria-dependent apoptosis and improving mitochondrial function. In addition, FUNDC1 enhanced mitophagy. The protective effects of FUNDC1 against apoptosis and mitochondrial dysfunction were reversed by 3-methyladenine (3-MA), an autophagy inhibitor. Taken together, our results confirm that FUNDC1 can protect against neuronal loss after SCI by inducing mitophagy, inhibiting mitochondria-dependent apoptosis, and improving mitochondrial function.

Transcriptome analysis reveals the impact of NETs activation on airway epithelial cell EMT and inflammation in bronchiolitis obliterans.

Bronchiolitis obliterans (BO) is a chronic airway disease that was often indicated by the pathological presentation of narrowed and irreversible airways. However, the molecular mechanisms of BO pathogenesis remain unknown. Although neutrophil extracellular traps (NETs) can contribute to inflammatory disorders, their involvement in BO is unclear. This study aims to identify potential signaling pathways in BO by exploring the correlations between NETs and BO. GSE52761 and GSE137169 datasets were downloaded from gene expression omnibus (GEO) database. A series of bioinformatics analyses such as differential expression analysis, gene ontology (GO), Kyoto encyclopedia of genes and genomes (KEGG), and gene set enrichment analysis (GSEA) were performed on GSE52761 and GSE137169 datasets to identify BO potential signaling pathways. Two different types of BO mouse models were constructed to verify NETs involvements in BO. Additional experiments and bioinformatics analysis using human small airway epithelial cells (SAECs) were also performed to further elucidate differential genes enrichment with their respective signaling pathways in BO. Our study identified 115 differentially expressed genes (DEGs) that were found up-regulated in BO. Pathway enrichment analysis revealed that these genes were primarily involved in inflammatory signaling processes. Besides, we found that neutrophil extracellular traps (NETs) were formed and activated during BO. Our western blot analysis on lung tissue from BO mice further confirmed NETs activation in BO, where neutrophil elastase (NE) and myeloperoxidase (MPO) expression were found significantly elevated. Transcriptomic and bioinformatics analysis of NETs treated-SAECs also revealed that NETs-DEGs were primarily associated through inflammatory and epithelial-to-mesenchymal transition (EMT) -related pathways. Our study provides novel clues towards the understanding of BO pathogenesis, in which NETs contribute to BO pathogenesis through the activation of inflammatory and EMT associated pathways. The completion of our study will provide the basis for potential novel therapeutic targets in BO treatment.

Severe pneumonia and pathogenic damage in human airway epithelium caused by Coxsackievirus B4.

Coxsackievirus B4 (CVB4) has one of the highest proportions of fatal outcomes of other enterovirus serotypes. However, the pathogenesis of severe respiratory disease caused by CVB4 infection remains unclear. In this study, 3 of 42 (7.2%, GZ-R6, GZ-R7 and GZ-R8) patients with severe pneumonia tested positive for CVB4 infection in southern China. Three full-length genomes of pneumonia-derived CVB4 were sequenced and annotated for the first time, showing their high nucleotide similarity and clustering within genotype V. To analyze the pathogenic damage caused by CVB4 in the lungs, a well-differentiated human airway epithelium (HAE) was established and infected with the pneumonia-derived CVB4 isolate GZ-R6. The outcome was compared with that of a severe hand-foot-mouth disease (HFMD)-derived CVB4 strain GZ-HFM01. Compared with HFMD-derived CVB4, pneumonia-derived CVB4 caused more intense and rapid disruption of HAE polarity, leading to tight-junction barrier disruption, loss of cilia, and airway epithelial cell hypertrophy. More pneumonia-derived CVB4 were released from the basolateral side of the HAE than HFMD-derived CVB4. Of the 18 cytokines tested, only IL-6 and IL-1b secretion significantly increased on bilateral sides of HAE during the early stage of pneumonia-derived CVB4 infection, while multiple cytokine secretions significantly increased in HFMD-derived CVB4-infected HAE. HFMD-derived CVB4 exhibited stronger neurovirulence in the human neuroblastoma cells SH-SY5Y than pneumonia-derived CVB4, which is consistent with the clinical manifestations of patients infected with these two viruses. This study has increased the depth of our knowledge of severe pneumonia infection caused by CVB4 and will benefit its prevention and treatment.

A novel PRKDC mutation caused B lymphocytes V(D)J rearrangement disorder in the SLE-DAH like symptoms patient.

BACKGROUND: Analyzed the clinical features and treatment process of the patient suffering from immunodeficiency with systemic lupus erythematosus(SLE)-like syndrome in a novel mutation of PRKDC. CASE PRESENTATION: The patient had multiple positive auto-antibodies, chest CT and bronchoscopy showed Diffuse alveolar hemorrhage(DAH), and psychiatric symptoms showed brain atrophy by magnetic resonance imaging (MRI). Whole exon sequencing showed that novel complex heterozygous mutations of PRKDC gene (C. 1777 - 710_1777-709INSA (IVS16/IC16), C.1337T > A(p.Phe446Tyr). The mature B cell (CD19 + CD27 + CD38 dimIgD IgM-) were absent. The treatment of high-dose methylprednisolone (MP) and cyclophosphamide(CTX) can quickly relieve the symptoms of the patient. CONCLUSION: We described the case of an infant immunodeficiency with SLE like-syndrome, which may cause by PRKDC mutation, treated successfully with high-dose MP and CTX.

Identification of Hub Genes in the Pathogenesis of Bronchiolitis Obliterans via Bioinformatic Analysis and Experimental Verification.

Background: Bronchiolitis obliterans (BO) is a chronic disease that can arise as a complication of severe childhood pneumonia and can also impact the long-term survival of patients after lung transplantation. However, the precise molecular mechanism underlying BO remains unclear. We aimed to identify BO-associated hub genes and their molecular mechanisms. Methods: BO-associated transcriptome datasets (GSE52761, GSE137169, and GSE94557) were downloaded from the Gene Expression Omnibus (GEO) database to identify differentially expressed genes (DEGs). Additional bioinformatics analyses, such as Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Protein-Protein Interaction (PPI) analyses, were performed to determine functional roles and DEG-associated regulatory networks. Prediction of hub genes using the 12 algorithms available in the Cytohubba plugin of Cytoscape software was also performed. Verification was performed using the BO mouse model. Results: Our results revealed 57 DEGs associated with BO, of which 18 were down-regulated and 39 were up-regulated. The Cytohubba plugin data further narrowed down the 57 DEGs into 9 prominent hub genes (CCR2, CD1D, GM2A, TFEC, MPEG1, CTSS, GPNMB, BIRC2, and CTSZ). Genes such as CCR2, TFEC, MPEG1, CTSS, and CTSZ were dysregulated in 2,3-butanedione-induced BO mice, whereas TFEC, CTSS, and CTSZ were dysregulated in nitric acid-induced BO mouse models. Conclusion: Our study identified and validated four novel BO biomarkers, which may allow further investigation into the development of distinct BO diagnostic markers and novel therapeutic avenues.

METTL3 Affects Spinal Cord Neuronal Apoptosis by Regulating Bcl-2 m6A Modifications After Spinal Cord Injury.

OBJECTIVE: Spinal cord injury (SCI) is a severe type of neurological trauma. N6-methyladenosine (m6A) modification is one of the most common internal modifications of RNA. The role of METTL3, the predominant methylation enzyme of m6A modification, in SCI remains unclear. This study aimed to investigate the role of methyltransferase METTL3 in SCI. METHODS: After establishing the oxygen-glucose deprivation (OGD) model of PC12 cells and rat spinal cord hemisection model, we found that the expression of METTL3 and the overall m6A modification level were significantly increased in neurons. The m6A modification was identified on B-cell lymphoma 2 (Bcl-2) messenger RNA (mRNA) by bioinformatics analysis, and m6A-RNA immunoprecipitation and RNA immunoprecipitation. In addition, METTL3 was blocked by the specific inhibitor STM2457 and gene knockdown, and then apoptosis levels were measured. RESULTS: In different models, we found that the expression of METTL3 and the overall m6A modification level were significantly increased in neurons. After inducing OGD, inhibition of METTL3 activity or expression increased the mRNA and protein levels of Bcl-2, inhibited neuronal apoptosis, and improved neuronal viability in the spinal cord. CONCLUSION: Inhibition of METTL3 activity or expression can inhibit the apoptosis of spinal cord neurons after SCI through the m6A/Bcl-2 signaling pathway.

Epidemiology of respiratory syncytial virus in hospitalized children with community-acquired pneumonia in Guangzhou: a 10-year study.

Background: Respiratory syncytial virus (RSV) is one of the most common virus causing community-acquired pneumonia (CAP) in children. To guide the prevention, diagnosis and treatment of RSV, we aimed to analyze the epidemiology of RSV in hospitalized children with CAP. Methods: A total of 9,837 hospitalized children (≤14 years old) with CAP from January 2010 to December 2019 were reviewed. Using the real-time polymerase chain reaction (RT-PCR), the oropharyngeal swab specimens were collected and tested for RSV, influenza virus A (INFA), influenza virus B (INFB), parainfluenza virus (PIV), enterovirus (EV), coronavirus (CoV), human metapneumovirus (HMPV), human bocavirus (HBoV), human rhinovirus (HRV), and adenovirus (ADV) for each patient. Results: The detection rate of RSV was 15.3% (1,507/9,837). From 2010 to 2019, the RSV detection rate showed a wavy change (χ2=166.982, P<0.001), with the highest detection rate in 2011 (158/636, 24.8%). RSV can be detected throughout the year, with the highest detection rate in February (123/482, 25.5%). Children younger than 0.5 years old had the highest detection rate (410/1,671, 24.5%). The detection rate of RSV in male children (1,024/6,226, 16.4%) was higher than that in female children (483/3,611, 13.4%) (P<0.001). A proportion of 17.7% (266/1,507) of RSV positive cases were also co-infected with other viruses, and INFA (41/266, 15.4%) was the most common coinfection virus. After adjusting for potential confounders, the RSV-positive children were associated with increased risk of severe pneumonia [odds ratio (OR) 1.26, 95% confidence interval (CI): 1.04 to 1.53, P=0.019]. Moreover, children with severe pneumonia had significantly lower cycle threshold (CT) values of RSV than those without severe pneumonia (28.88±3.89 vs. 30.42±3.33, P<0.01). Patients with coinfection (38/266, 14.3%) had a higher risk of severe pneumonia than those without coinfection (142/1,241, 11.4%), but the difference was not statistically significant (OR 1.39, 95% CI: 0.94 to 2.05, P=0.101). Conclusions: The detection rate of RSV in CAP hospitalized children changed by years, months, ages, and sexes. CAP hospitalized children with RSV are more likely to develop severe pneumonia than those without RSV. Policy makers and doctors should make timely adjustments to prevention measures, medical resources and treatment options based on these epidemiological characteristics.

Quantitative cost­effectiveness index of cancer treatments.

In spite of advancements being made in technology and treatment strategies, which have markedly improved the survival rate of patients, the cost of cancer care worldwide has increased over the past decades. The presence of several cost-effectiveness ratios has provided significant indexes to assess the balance between cost and effectiveness. However, the currently available indexes still fail to provide a comprehensive and objective evaluation of cancer treatment. Therefore, the present study developed a novel approach, namely a quantitative cost-effectiveness index of cancer treatment, based on the calculation of the hospitalization expense index and efficacy evaluation index. The present study used the data of 16 patients with childhood acute myeloid leukemia who received the high-dose chemotherapy as an example, and the quantitative cost-effectiveness index was used to evaluate the value of this approach. As the increasing prevalence of cancer and the rising cost of pharmaceuticals have contributed to the expenditure, the development of this index may help to solve the current dilemma of cancer treatment and may prove to be essential for the development of an effective approach which may be accessible to and affordable by common persons; thus would then lead to a higher cure rate.

The effect of therapeutic bronchoalveolar lavage in combination with glucocorticoids on children with acute exogenous lipoid pneumonia.

BACKGROUND: Exogenous lipoid pneumonia (ELP) is a rare disease caused by the inhalation of oily materials in the alveoli with the pathological characterization by the presence of laden-lipid macrophages in the respiratory specimens. At present, the treatment norm for ELP has not well defined, and so the aim of this study is to evaluate the effect of bronchoalveolar lavage in combination with glucocorticoids on children with ELP. METHODS AND MATERIALS: We retrospectively reviewed 17 children with a confirmed history of exogenous oily materials aspiration, admitted to the First Affiliated Hospital of Guangzhou Medical University from June 2012 to December 2021. Clinical features, blood investigations, tomographic evaluations, therapeutic bronchoalveolar lavage and glucocorticoids use were carried out at the beginning of therapy and throughout a follow-up period. RESULTS: The included children are the median age of 2 years. Fever, dypnea and tachypnea were the most common symptoms. The most common radiological features were airspace consolidations (15, 93.75%). Chest CT scans showed areas of consolidation with air bronchogram (15, 93.75%), poorly defined centrilobular nodules (13, 81.25%), areas of ground-glass attenuation (11, 68.75%) and 'crazy-paving' pattern (6, 37.5%) in the both lower, right middle lung lobes. Neutrophil percentage of peripheral blood and bronchoalveolar lavage fluid exhibited a significantly higher than the normal range. After treatment with multiple bronchoalveolar lavages and local administration of budesonide during the hospital stay, taken by oral prednisolone (1 ~ 2 mg/kg) after discharge, all of children became asymptomatic and presented normal radiological imagings in the follow-up period. CONCLUSION: The most frequently findings in the CT scan of ELP were consolidations and ground-glass attenuation in the both lower and right middle lung lobes. Multiple bronchoalveolar lavages in combination with oral prednisolone for children who had a confirmed history of exogenous oily substances ingestion were an efficient and safe for the clearance of oily materials from the lung and the prevention of fibrosis. This strategy contributed to reducing the damage of ELP in children patients.

Improving the efficiency and biosafety of respiratory syncytial virus identification using a nucleic acid extraction-free reagent.

Respiratory syncytial virus (RSV) is the most important virus that causes lower respiratory tract disease in children; efficient viral identification is an important component of disease prevention and treatment. Here, we developed and evaluated a ready-to-use (RTU) nucleic acid extraction-free direct reagent for identification of RSV (RTU-Direct test) in clinical samples. The limit of detection (LOD) of the RSV RTU-Direct test was consistent with the LOD of the standard test using extracted nucleic acids. The virus inactivation ability of RTU-Direct reagent was confirmed by viral infectivity assays involving RTU-Direct-treated samples containing RSV and human coronavirus OC43. RSV RNA stability was significantly better in RTU-Direct reagent than in conventional virus transport medium (VTM) at room temperature and 4°C (p < 0.05). The clinical performance of the RTU-Direct test was evaluated using 155 respiratory specimens from patients with suspected RSV infection. Positive agreement between the RTU-Direct test and the VTM standard test was 100% (42/42); negative agreement was 99.1% (112/113), and the kappa statistic was 0.968 (p < 0.001). The distributions of Ct values did not significantly differ between the RTU-Direct test and the standard test (p > 0.05). Overall, the RTU-Direct reagent can improve the efficiency and biosafety of RSV detection, while reducing the cost of detection.

A clinical report on high­dose cytarabine therapy for children with acute myeloid leukemia.

Despite improvement in the long-term survival rate following pediatric acute myeloid leukemia (AML), the rate remains low, even with optimal treatment. The present study reports the long-term outcome of a small patient group treated with a single drug, high-dose chemotherapy (HDCT) with cytarabine, including consolidation and maintenance therapy. RT-PCR was conducted to assess 43 fusion genes, and after treatment, all cases have been followed up for 20 years (June 2002-December 2020). With an 80% 5-year survival rate, the results of this study highlight the possibility that pediatric AML can be reasonably effectively treated with relatively simple chemotherapy when necessary. HDCT is clinically safe, effective and relatively inexpensive. We propose that in the context of limited resources, HDCT should be considered as an alternative therapy for pediatric AML.

A juvenile murine model with chronic lung inflammation induced by repeated intratracheal instillation of lipopolysaccharides: a versatile and replicable model.

Background: Recurrent lower respiratory tract infection or chronic pulmonary infection often occur in children with chronic lung diseases (CLDs). By continuous lung inflammation, recurrent and chronic infection could cause irreversible airway structural and lung function damage, which eventually leads to respiratory failure and death. Methods: In purpose of recapitulating persistent high-intensity lung inflammation caused by recurrent lower respiratory tract infection or chronic infection, we established a juvenile murine model with chronic lung inflammation induced by repeated intratracheal instillations of lipopolysaccharides (LPS) from Pseudomonas aeruginosa once a week for 4 weeks. Four-week-old C57BL/6N mice were divided into 4 groups, including LPS0.5 group (n=15), LPS1.0 group (n=15), Control group (n=15) and Normal group (n=15). Mice in LPS0.5 group and LPS1.0 group were instilled intratracheally with 0.5 mg/kg LPS and 1.0 mg/kg LPS respectively. Mice in control group were instilled intratracheally with LPS-free sterile 0.9% NaCl, whereas normal group received no treatment. The successful chronic lung inflammation murine model was validated via (I) pathological manifestations of chronic inflammatory mononuclear-cell infiltration and lung parenchyma damage; (II) decreased lung function. Results: All mice in LPS1.0 group died before the third instillation. No death after instillation was observed in Control and LPS0.5 group. Histological analysis revealed that in LPS0.5 group, 7 days after the third instillation, most bronchus and parabronchial vessels were wrapped by infiltrating monocytes and lymphocyte and alveolar cavities were compressed, which were not observed in control and normal group. Also, ratio of forced expiratory volume in 0.1 second (FEV0.1) and forced vital capacity (FVC) in LPS0.5 group was significantly lower (P<0.0001) than both control group and normal group, suggesting ventilatory dysfunction developed after repeatedly intratracheal instillation once a week for 4 weeks. Conclusions: Intratracheal instillation of 0.5 mg/kg LPS once a week for 4 weeks can cause chronic lung inflammation in young mice.

Human coronaviruses: Origin, host and receptor.

Coronavirus is a type of RNA-positive single-stranded virus with an envelope, and the spines on its surface derived its official name. Seven human coronaviruses 229E, OC43, SARS, NL63, HKU1, MERS, SARS-CoV-2 can cause both a mild cold and an epidemic of large-scale deaths and injuries. Although their clinical manifestations and many other pathogens that cause human colds are similar, studying the relationship between their evolutionary history and the receptors that infect the host can provide important insights into the natural history of human epidemics in the past and future. In this review, we describe the basic virology of these seven coronaviruses, their partial genome characteristics, and emphasize the function of receptors. We summarize the current understanding of these viruses and discuss the potential host of wild animals of these coronaviruses and the origin of zoonotic diseases.

Human Adenovirus Subtype 21a Isolates From Children With Severe Lower Respiratory Illness in China.

Human adenovirus type 21 (HAdV-21) is an important pathogen associated with acute respiratory infection (ARI), but it was rarely reported and characterized so far. In this study, 151 of 1,704 (8.9%) pediatric patients (≤14 years old) hospitalized with ARI in Guangzhou, China in 2019 were positive for HAdV which was the third most frequently detected pathogen. Two HAdV-21-positive patients presented with severe lower respiratory illness and had similar initial symptoms at onset of illness. Then two HAdV-21 strains were isolated and characterized. The two HAdV-21 strains were sequenced and classified as subtype 21a with genomes closely related to strain BB/201903 found in Bengbu, China in March 2019. Phylogenetic analysis for whole genome and major antigen proteins of global HAdV-21 strains showed that HAdV-21 could be classified into two branches, branch 1 including genotype 21p, branch 2 including all other strains dividing into genotype 21a and 21b. There was no significant difference in the plaque size, or the replication curves between the two HAdV-21a strains and the prototype strain HAdV-21p AV-1645. However, there were five highly variable regions (HVR1, HVR3, HVR4, HVR5, and HVR7) in the hexon protein that varied between two branches. Mice immunized with one branch strain showed 2-4-fold lower neutralizing antibody titers against another branch strain. In summary, this study firstly reported two HAdV-21a infections of children in China, characterized two isolates of HAdV-21a associated with severe lower respiratory illness; our results could be important for understanding the HAdV-21 epidemiology and pathogenic, and for developing HAdV-21 vaccine and drug.

3D printing monetite-coated Ti-6Al-4V surface with osteoimmunomodulatory function to enhance osteogenesis.

Titanium and its alloys are widely used in orthopedic implant surgery due to their good mechanical properties and biocompatibility. Recent studies have shown that the healing process of fractures involve not only the calcification of osteoblasts but also the regulation of the immune system. The functionalization of titanium surface coatings is one of the most important methods for solving implant failures. In this study, monetite (CaHPO4) was coated on the Ti-6Al-4V porous scaffold by hydrothermal method. SEM, XRD and EDS were used to characterize the morphology, phase constitutes, elemental content of the coating, respectively. The results indicated that a well bonded and uniformly distributed monetite coating obtained, and the degradation performance and Ca2+ release of the surface coating were also studied. In terms of biology, live/dead staining and CCK8 methods showed the coating had good biocompatibility and BMSCs can adhere and proliferate on the surface. Flow cytometry and ELISA indicated that the surface monetite-coating had good anti-inflammatory properties. Through RNA-seq analysis, it was shown in KEGG that the osteoclast-related pathway was inhibited. In vitro, monetite induced osteogenic gene expression in BMSCs and inhibited the activity of osteoclasts. In vivo experiments showed that the monetite-coating increased bone formation. In summary, monetite-coating can effectively promote the osteogenesis in BMSCs, which may be achieved through bone immune regulation.

Seroprevalence of neutralizing antibodies against the respiratory syncytial virus in healthy adults in Guangzhou, southern China.

Respiratory syncytial virus (RSV) is the major cause of pneumonia and bronchiolitis in infants and young children and mediates substantial morbidity and mortality in the elderly and immunocompromised globally. The development of a safe and effective RSV vaccine and an optimized neutralizing antibody (NAb) with strong virus-neutralizing activity is appealing. To gain some detailed knowledge of the humoral immune response to RSV subgroup A (RSV-A) and RSV-B, we investigated the seroprevalence of pre-existing NAbs by using the microneutralization assay in healthy adult from Guangzhou, southern China. We found that the overall seropositive rate was 84.86% for anti-RSV NAbs. Furthermore, the seropositive rates were 68.47% and 73.61% for anti-RSV-A NAbs and anti-RSV-B NAbs, respectively. In addition, although the seropositive rates and NAb levels were not associated with the blood type, type AB individuals displayed higher seropositive rates for anti-RSV-A NAbs with high titer (≥ 288) and anti-RSV-B NAbs, especially those with moderate titer (≥ 72 to < 288). The seropositive rates and titers were comparable between anti-RSV-A NAbs and anti-RSV-B NAbs in the AB blood type group. Interestingly, only when the NAb titer of the serum to RSV-A was not less than 288, was it not less than 18 to RSV-B, and vice versa. These results would be helpful for a better understanding of the human serum NAb responses to RSV-A and RSV-B.

Analysis of severe human adenovirus infection outbreak in Guangdong Province, southern China in 2019.

During 2018-2019, a severe human adenovirus (HAdV) infection outbreak occurred in southern China. Here, we screened 18 respiratory pathogens in 1704 children (≤ 14 years old) hospitalized with acute respiratory illness in Guangzhou, China, in 2019. In total, 151 patients had positive HAdV test results; 34.4% (52/151) of them exhibited severe illness. HAdV infection occurred throughout the year, with a peak in summer. The median patient age was 3.0 (interquartile range: 1.1-5.0) years. Patients with severe HAdV infection exhibited increases in 12 clinical indexes (P â€‹≤ â€‹0.019) and decreases in four indexes (P â€‹≤ â€‹0.007), compared with patients exhibiting non-severe infection. No significant differences were found in age or sex distribution according to HAdV infection severity (P â€‹> â€‹0.05); however, the distributions of comorbid disease and HAdV co-infection differed according to HAdV infection severity (P â€‹< â€‹0.05). The main epidemic types were HAdV-3 (47.0%, 71/151) and HAdV-7 (46.4%, 70/151). However, the severe illness rate was significantly higher in patients with HAdV-7 (51.4%) than in patients with HAdV-3 (19.7%) and other types of HAdV (20%) (P â€‹< â€‹0.001). Sequencing analysis of genomes/capsid genes of 13 HAdV-7 isolates revealed high similarity to previous Chinese isolates. A representative HAdV-7 isolate exhibited a similar proliferation curve to the curve described for the epidemic HAdV-3 strain Guangzhou01 (accession no. DQ099432) (P â€‹> â€‹0.05); the HAdV-7 isolate exhibited stronger virulence and infectivity, compared with HAdV-3 (P â€‹< â€‹0.001). Overall, comorbid disease, HAdV co-infection, and high virulence and infectivity of HAdV-7 were critical risk factors for severe HAdV infection; these data can facilitate treatment, control, and prevention of HAdV infection.