IntroductionCarbapenem-resistant Enterobacteriaceae (CRE) is the most common clinical pathogens. Investigating the antimicrobial resistance, hypervirulence and clinical characteristics of CRE isolated from children is helpful to guide for anti-infection treatments.MethodsNonduplicated CRE clinical strains were isolated and mass spectrometry was applied to identify clinical isolated strains. VITEK 2 Compact system and Kirby-Bauer method were used to analyze the antimicrobial susceptibility. Besides, the drug resistance and hypervirulence associated genes were detected by polymerase chain reaction (PCR) and sequencing.ResultsA total of 281 non-duplicated CRE strains were identified in this study. Klebsiella pneumoniae (55.87%), Escherichia coli (36.65%) and Klebsiella aerogenes (3.20%) were the top 3 CRE strains. These strains showed high resistance to most of antimicrobial agents and carried carbapenemase genes, including blaOXA-232 (38.08%), blaKPC-2 (20.28%), blaOXA-1 (17.08%), blaNDM-5 (10.32%) and blaNDM-1 (8.90%). In addition, blaTEM-1 (98.93%), blaCTX-M-14 (88.61%) and blaSHV-11 (87.54%) were the prevalent extended-spectrum β-lactamase (ESBL) genes in these strains, while the detection rate of AmpC cephalosporinase genes were not high. Besides, 45 (28.66%) carbapenem-resistant Klebsiella pneumoniae (CRKP) strains carried hypervirulence associated genes iucA (24.84%), prmpA (17.83%), peg-344 (17.20%), and prmpA2 (9.55%). Among them, 22 (14.01%) CRKP strains were also identified as carbapenem-resistant and hypervirulent Klebsiella pneumoniae (CR-HVKP). What’s worse, the patients infected with CR-HVKP had a worse prognosis overall.ConclusionThis study revealed the drug resistance, hypervirulence and epidemiology of CRE strains in pediatric patients in Suzhou of eastern China. Unfortunately, CR-HVKP strains with more several infection were also identified, which should be of great concern to clinicians.

MicroRNAs (miRNAs) have emerged as critical epigenetic regulators in the pathogenesis of childhood bronchial asthma. This study employed high-throughput sequencing to explore miRNA expression profiles in an asthma cohort, with a focus on elucidating the functional mechanisms of key miRNAs. Notably, among the miRNAs validated by RT-qPCR, miR-31-5p exhibited the largest area under the curve (AUC) value and demonstrated significant anti-inflammatory effects in an OVA-induced allergic inflammation mouse model. Bioinformatics analysis and dual-luciferase reporter assays confirmed that TBXA2R is a direct target of miR-31-5p. Mechanistically, stimulation with house dust mite (HDM) and IL-4 downregulated miR-31-5p expression in A549 cells, accompanied by elevated levels of TBXA2R and eotaxins (CCL11, CCL24, CCL26). Conversely, overexpression of miR-31-5p suppressed TBXA2R-mediated eotaxin production. These findings highlight the significant role of miR-31-5p in peripheral blood mononuclear cells (PBMCs) of asthmatic children, suggesting its potential involvement in upregulating eotaxin expression in A549 cells through negative regulation of TBXA2R.

To examine chemokine expression in children with Respiratory Syncytial Virus (RSV) bronchiolitis and evaluate its clinical utility for early warning and prognosis. Five hospitalised RSV bronchiolitis children and five matched controls were studied. To validate findings, 50 RSV infants and 30 controls were assessed for recurrent wheezing after 1 year. Blood leukocyte RNA-seq identified RSV-associated hub genes via GO/KEGG analysis, with flow cytometry confirming chemokine expression. Twelve hub genes were identified, with 712 differentially expressed genes (292 upregulated, 420 downregulated). RSV patients showed elevated CXCL2, CXCL12, CXCL13, CCL13, and CCL24 (P < 0.05). CXCL12 was higher in moderate-to-severe cases (Area Under the Curve, AUC = 0.835, 95% CI 0.714-0.956, P < 0.05), while CXCL13 was elevated in recurrent wheezers (AUC = 0.851, 95% CI 0.711-0.991, P < 0.05). CXCL12 predicted severity, and CXCL13 predicted recurrence (ROC-confirmed, P < 0.05). CXCL12 and CXCL13 may serve as biomarkers for assessing RSV bronchiolitis severity and predicting recurrence, aiding early clinical evaluation and prognosis.

Mycoplasma pneumoniae caused lower respiratory tract infection in children and can exacerbate these infections through the production of various inflammatory factors, with chemokines playing a key role. However, the pathogenesis of this infection is complicated and thus has not been thoroughly studied. We clarified that cytokine expression levels were analyzed in both peripheral blood and bronchoalveolar lavage fluid (BALF), and in vitro assays were conducted using THP-1 macrophages. We discovered that, compared to control children, M. pneumoniae pneumonia (MPP) patients expressed significantly higher levels of CXCL10 both in the peripheral blood and BALF. Moreover, numbers of macrophages, predominantly with a M1 phenotype, were significantly increased in BALFs of children of MPP. In vitro, coculture with IFN-γ or activated CD4+ Th1 cells significantly promoted CXCL10 expressions in THP-1 derived macrophages, which was largely reversed by siRNA-mediated down regulation of STAT1. In addition, IFN-γ-stimulated macrophages greatly promoted the trans-migration of Th1 cells. our data show that Th1 cells-derived IFN-γ augments CXCL10 production in macrophages via the JAK-STAT1 pathway, which subsequently recruits more immune cells like Th1 cells into the infection sites, thereby constituting a positive feedback loop and aggravating the type I inflammatory responses in MPP patients.

BACKGROUND:Lower respiratory infections are the leading cause of illness and death in children under 5, primarily due to respiratory syncytial virus(RSV). Climate and pollution influence disease and pathogen prevalence. This study investigates the correlation between meteorological factors, atmospheric pollutants, and RSV infections in children, aiming to implement effective clinical measures and reduce RSV risk in children by enhancing the environment. METHODS:This study included patients with lower respiratory tract infections who were hospitalized in the Department of Respiratory Medicine at Children's Hospital of Soochow University from January 2006 to December 2019 as the research subjects. This study analyzed detection rates across different ages, genders, and seasons, while also examining the relationship of RSV infection between meteorological factors and atmospheric pollutants. RSV was detected using direct immunofluorescence, and an LS-SVM prediction model with lag nonlinear curves was established in conjunction with meteorological data. In this model, monthly average temperature, atmospheric pollutant levels, and average monthly wind speed were used as predictive variables for construction and prediction. A distributed lag nonlinear model (DLNM) was developed, which included the creation of a lag nonlinear curve by integrating meteorological data. RESULTS:A total of 19,637 pediatric cases of lower respiratory tract infections were included in this study. The detection rate of RSV over 14 years averaged 14.9% (2934/19637). The male-to-female ratios for positive detection was 1.2:1. The primary detection season for RSV is winter, with a detection rate of 33.7%. The prevalence of RSV was correlated with climatic factors and atmospheric pollution. Utilizing the monthly average temperature, monthly average wind speed, and levels of atmospheric pollutants as the predictive factors in LS-SVM for model construction and prediction, a DLNM identified that the relative risk (RR) of RSV infection fluctuated with changes in the temperature and wind speed. CONCLUSION:RSV has the highest detection rate in infants and is often detected during winter.The influence of meteorological factors and atmospheric pollutants on RSV infection rates cannot be overlooked, with observation of a lag effect.

Background: Cytokine levels in the peripheral blood of children infected with the influenza A virus are significantly associated with disease diagnosis and severity. This study aimed to investigate the correlation between the expression levels of six cytokines in the peripheral blood of pediatric patients with influenza and the diagnosis and severity of their condition. Methods: The levels of six cytokines were measured using a flow cytometric microsphere array. Statistical analysis was performed using IBM SPSS Statistics 26.0 to compare differences between the groups, with a P value of less than 0.05 considered statistically significant. Results: Univariate analysis showed that the levels of interferon alpha-2 (IFN-alpha 2), monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), and interleukin-18 (IL-18) were significantly elevated in the influenza group (P <= 0.001). IL-18 levels were higher in the H3N2 group than in the H1N1 group (P=0.03), and IFN-alpha 2 levels were higher in the Mycoplasma coinfection group compared to the influenza-only group (P=0.04). Notably, significant differences in IFN-alpha 2 and MCP-1 levels were observed between the mild-moderate and severe influenza A subgroups (P=0.008, P=0.01, respectively). Negative correlations were found between the severity of influenza A and the levels of IFN-alpha 2 and MCP-1 (r=-0.357, P=0.006 and r=-0.329, P=0.01, respectively). Multifactorial logistic regression and receiver operating characteristic (ROC) curve analysis identified IFN-alpha 2 and MCP-1 as independent risk factors for severe influenza A. Conclusions: Inflammatory cytokine levels are critical in modulating the immune and inflammatory responses of the body. IFN-alpha 2 and MCP-1 could serve as early indicators of severe influenza A. IL-18 levels were significantly higher in the H3N2 group compared to the H1N1 group, this finding may aid in differentiating between influenza subtypes, providing insights for tailored interventions.

Objective: To investigate the significance of VISTA in bronchial asthma and its impact on the disease. Methods: Human peripheral blood of asthma children was gathered. The expression concentrations of VISTA, IL-4, IL-6, CD25, CD40L, and PD-L2 in peripheral blood plasma were detected by ELISA. We established the mouse model of asthma and intervened with agonistic anti-VISTA mAb (4C11) and VISTA fusion protein. ELISA, flow cytometry, and Western blotting were performed to detect the expression levels of Th1, Th2, and Th17 cell subsets and related characteristic cytokines, as well as the protein levels of MAPKs, NF-kappa B, and TRAF6 in lung tissues. In addition, the infiltration of eosinophils and inflammatory cells, airway mucus secretion, and VISTA protein expression in lung histopathological sections of different groups of mice were analyzed. Results: The concentration of VISTA in human asthma group decreased significantly (p < 0.05); A positive correlation was observed between VISTA and CD40L. The intervention of 4C11 mAb and fusion protein respectively during the induction period increase the differentiation of Th1 cells and the secretion of IFN-gamma, and inhibit the differentiation of Th2 and Th17 cells, as well as the secretion of IL-4, IL-5, IL-13 and IL-17, partially reduce the pathological changes of asthma in mouse lungs and correct the progress of asthma. The MAPK, NF-kappa B, and TRAF6 protein levels were the middle range in the 4C11 mAb and fusion protein groups (p < 0.05). Conclusion: The findings suggest VISTA may play a negative regulatory role in the occurrence and development of bronchial asthma.

Background: Neutrophilic asthma is characterized by the predominant infiltration of neutrophils in airway inflammation. Objective: To explore the therapeutic potential of an antibody against the inducible T cell co-stimulator ligand (ICOSL) in a mouse model of neutrophilic asthma. Methods: Female BALB/c mice were randomly assigned to different groups. They were then injected with ovalbumin (OVA)/lipopolysaccharides (LPS) to induce neutrophilic asthma. The mice were then treated with either anti-ICOSL (the I group), control IgG (the G group), or no treatment (the N group). Additionally, a control group of mice received vehicle PBS and was labeled as the C group (n=6 per group). One day after the last allergen exposure, cytokine levels were measured in plasma and bronchoalveolar lavage fluid (BALF) using ELISA. After analyzing and categorizing BALF cells, the lung tissues were examined histologically and immunohistochemically. Results: Administering anti-ICOSL resulted in a significant decrease in the total number of inflammatory infiltrates and neutrophils found in BALF. Moreover, it led to a decrease in the levels of interleukin (IL)-6, IL-13, and IL-17 in both BALF and plasma. Additionally, there was an increase in IFN-gamma levels in the BALF of asthmatic mice (p<0.05 for all). Treatment with anti-ICOSL also reduced lung interstitial inflammation, mucus secretion, and ICOSL expression in asthmatic mice. Conclusion: The treatment of anti-ICOSL effectively improved lung interstitial inflammation and mucus secretion in mice with neutrophilic asthma by restoring the balance of Th1/Th2/Th17 responses. These findings indicate that blocking the ICOS/ICOSL signaling could be an effective way to manage neutrophilic asthma.

Abstract Objective To investigate the etiological characteristics of plastic bronchitis (PB) caused by pulmonary infections in children and to identify any differences in the clinical features of PB cases caused by different pathogens. Method We collected data on children diagnosed with PB and admitted to the Respiratory Department at Soochow University Children’s Hospital between July 2021 and March 2023 utilizing electronic bronchoscopy. We analyzed clinical characteristics and the species of pathogens causing the illness in these children. Result A total of 45 children were enrolled. The main clinical symptoms observed were cough (100%), fever (80%), shortness of breath (28.9%), and wheezing (20.0%). Pathogens were identified in 38 (84.4%) patients. Mycoplasma pneumoniae (MP) had the highest detection rate at 53.3%, followed by the Boca virus at 26.7%. MP-induced PB typically occurs in older children with an average age of 7.46 ± 2.36 years, with the main symptoms including high fever (85.7%) and local hyporespiration (42.9%). In contrast, Boca virus-induced PB tends to occur in younger children, with the main symptoms of moderate fever (54.5%), and wheezing (54.5%). The MP group exhibited a higher incidence of both internal and external pulmonary complications, including pleural effusion (42.9%), elevated aspartate aminotransferase (52.4%), lactic dehydrogenase (76.2%), and D-D dimer (90.5%). Conversely, the Boca virus group primarily showed pulmonary imaging of atelectasis (81.8%), with no pleural effusion. The average number of bronchoscopic interventions in the MP group was 2.24 ± 0.62, which was significantly higher than that required in the Boca virus group (1.55 ± 0.52). During the second bronchoscopy, 57.1% of children in the MP group still had visible mucus plugs, while none were observed in the Boca virus group. Conclusion MP and Boca virus are the primary pathogens responsible for PB among children. The clinical manifestations of PB typically vary significantly based on the pathogen causing the condition.

ObjectiveClimate and environmental change is a well-known factor causing bronchial asthma in children. After the outbreak of coronavirus disease (COVID-19), climate and environmental changes have occurred. The present study investigated the relationship between climate changes (meteorological and environmental factors) and the number of hospitalizations for pediatric bronchial asthma in Suzhou before and after the COVID-19 pandemic.MethodsFrom 2017 to 2021, data on daily inpatients diagnosed with bronchial asthma at Children's Hospital of Soochow University were collected. Suzhou Meteorological and Environmental Protection Bureau provided daily meteorological and environmental data. To assess the relationship between bronchial asthma-related hospitalizations and meteorological and environmental factors, partial correlation and multiple stepwise regression analyses were used. To estimate the effects of meteorological and environmental variables on the development of bronchial asthma in children, the autoregressive integrated moving average (ARIMA) model was used.ResultsAfter the COVID-19 outbreak, both the rate of acute exacerbation of bronchial asthma and the infection rate of pathogenic respiratory syncytial virus decreased, whereas the proportion of school-aged children and the infection rate of human rhinovirus increased. After the pandemic, the incidence of an acute asthma attack was negatively correlated with monthly mean temperature and positively correlated with PM2.5. Stepwise regression analysis showed that monthly mean temperature and O3 were independent covariates (risk factors) for the rate of acute asthma exacerbations. The ARIMA (1, 0, 0) (0, 0, 0) 12 model can be used to predict temperature changes associated with bronchial asthma.ConclusionMeteorological and environmental factors are related to bronchial asthma development in children. The influence of meteorological and environmental factors on bronchial asthma may be helpful in predicting the incidence and attack rates.

Background Refractory mycoplasma pneumoniae pneumonia (RMPP) is a serious mycoplasma pneumoniae infection and is difficult to diagnose early. The levels of serum soluble B7-dendritic cell (sB7-DC) in children with mycoplasma pneumoniae pneumonia (MPP) were assessed to explore the clinical significance of sB7-DC levels in RMPP. Methods A total of 65 patients with mycoplasma pneumoniae pneumonia (MPP) were enrolled in this study between January 2017 and December 2018. The patients were divided into the general mycoplasma pneumoniae pneumonia (GMPP) (n=30) and RMPP groups (n=35); the data of 20 normal children served as a control group (n=20). An enzyme-linked immunoassay kit was used to detect the expression of soluble B7-dendritic cell (sB7-DC) and other inflammatory factors. Binary logistic regression was performed to identify the independent predictors of RMPP. Receiver operating characteristic (ROC) curves were drawn to evaluate the value of each independent risk factor in the early diagnosis of RMPP. Results The results showed that compared to the GMPP group, children in the RMPP group had a significantly longer hospital stay and had a significantly longer fever duration (P<0.05). The values of interferon-gamma (IFN-γ), interleukin 17 (IL-17), and sB7-DC in the RMPP group were significantly higher than those in the normal control and GMPP groups (all P<0.05). The results of the correlation analysis showed that sB7-DC was positively correlated with IFN-γ and IL-17 and these indicators could be used in combination to evaluate the severity of the disease. The binary logistic regression analysis identified IL-17 and sB7-DC as independent risk factors for RMPP (P<0.05). The ROC curve analysis showed that the cut-off values of IL-17 and sB7-DC were 309.6 pg/L and 1,109.7 pg/mL, respectively. The areas under the curve (AUCs) of IL-17 and sB7-DC were 0.741 and 0.794, respectively. The sensitivity of IL-17 to RMPP prediction was 83.3%, and the specificity was 62.9%. The sensitivity and specificity of sB7-DC to RMPP were 86.7% and 62.9%, indicating that sB7-DC had the highest predictive power for RMPP. Conclusions The level of serum sB7-DC may play an important role in the early diagnosis of RMPP. Our research results provide a theoretical basis for the early diagnosis of RMPP.

BackgroundWithin the past 3-5 years, Mycoplasma pneumoniae has become a major pathogen of community-acquired pneumonia in children. The pathogenic mechanisms involved in M. pneumoniae infection have not been fully elucidated.MethodsPrevious protein microarray studies have shown a differential expression of CXCL9 after M. pneumoniae infection. Here, we conducted a hospital-based study to explore the clinical significance of the type 1 immune response inflammatory factors interferon (IFN)-γ and CXCL9 in patients with M. pneumoniae pneumonia (MPP). Then, through in vitro experiments, we explored whether CARDS toxin stimulated F-DCs (dendritic cells incubated with Flt3L) to promote Th-cell differentiation; we also investigated the IFN-γ-induced CXCL9 secretion pathway in macrophages and the role of CXCL9 in promoting Th1 cell migration.ResultsThe CXCL9 expression level was upregulated among patients with a higher fever peak, fever duration of greater than 7 days, an imaging manifestation of lobar or segmental, or combined pleural effusion (P<0.05). The peripheral blood levels of IFN-γ and CXCL9, which were higher in patients than in the healthy control group, were positively correlated with each other (r=0.502, P<0.05). In patients, the CXCL9 expression level was significantly higher in the bronchoalveolar lavage fluid (BALF) than in the peripheral blood, and the BALF CXCL9 expression level was higher than that in the healthy control group (all P<0.05). Our flow cytometry analysis revealed that M1-phenotype macrophages (CD16+CD64+CD163−) were predominant in the BALF from children with MPP. In in vitro experiments, F-DCs stimulated with CARDS toxin promoted the differentiation of CD4+IFN-γ+ Th (Th1) cells (P<0.05). Moreover, IFN-γ induced high levels of CXCL9 expression in M1-type macrophages in a dose-dependent and time-dependent manner. Additionally, macrophages transfection with STAT1-siRNA-1 downregulated the expression of CXCL9 (P<0.05), and CXCL9 promoted Th1 cell migration (P<0.05).ConclusionsOur findings suggest that CARDS toxin induces a type 1 immune response positive feedback loop during M. pneumoniae infection; this putative mechanism may be useful in future investigations of immune intervention approaches for M. pneumoniae pneumonia.

The role of micro RNAs (miRNAs) in asthma remains unclear. In this study, we examined the role of miRNA in targeting FOXO1 in asthma. Results showed that miR-493-5p was one of the differentially expressed miRNAs in the PBMCs of asthmatic children, and was also associated with Th cell differentiation. The miR-493-5p expression decreased significantly in the OVA-induced asthma mice than the control groups. The miR-493-5p mimic inhibited the expression of the IL-9, IRF4 and FOXO1, while the inhibitor restored these effects. Moreover, the Dual-Luciferase analysis results showed FOXO1 as a novel valid target of miR-493-5p. According to the rescue experiment, miR-493-5p inhibited Th9 cell differentiation by targeting FOXO1. Then the exosomes in association with the pathogenesis of asthma was identified. Various inflammatory cells implicated in asthmatic processes including B and T lymphocytes, DCs, mast cells, and epithelial cells can release exosomes. Our results demonstrated that the DC-derived exosomes can inhibit Th9 cell differentiation through miR-493-5p, thus DC-derived exosomal miR-493-5p/FOXO1/Th9 may serve as a potential therapeutic target in the development of asthma.

Objective: We sought to compare the clinical characteristics of pediatric respiratory tract infection and respiratory pathogen isolations during the coronavirus disease (COVID-19) pandemic to those of cases in 2018 and 2019.Methods: Our study included all children from 28 days to 15 years old with respiratory tract infections who were admitted to the Department of Respiration, in the Children's Hospital of Soochow University, between January 2018 and December 2020. Human rhinovirus (HRV) and human metapneumovirus (hMPV) were detected by reverse transcription polymerase chain reaction (RT-PCR). Mycoplasma pneumoniae (MP) and human bocavirus (HBoV) were detected by real-time fluorescence quantitative polymerase chain reaction (qPCR); In parallel, Mycoplasma pneumoniae was detected by enzyme-linked immunosorbent assays, and bacteria were detected by culture in blood, bronchoalveolar lavage specimen, and pleural fluid.Results: Compared to 2018 and 2019, the pathogen detection rate was significantly lower in 2020. With regard to infections caused by single pathogens, in 2020, the detection rates of MP were the lowest and those of HRV were the highest when compared to those in 2018 and 2019. Meanwhile, the positive rates of respiratory syncytial virus (RSV) and hMPV reported in 2020 were less than those recorded in 2018 but similar to those recorded in 2019. Also, the 2020 rate of adenovirus (ADV) was lower than that recorded in 2019, but similar to that recorded in 2018. There were no statistical differences in the positive rates of HBoV and PIV III over the 3 years surveyed. Infections in infants were significantly less common in 2020, but no significant difference was found among children aged 1 to 3 years. The detection rate of pathogens in children old than 5 years in 2020 was significantly lower than those recorded in the previous 2 years. Notably, the pathogen detection rates in the first and second quarters of 2020 were similar to those recorded in the previous 2 years; however, the rates were reduced in the third and fourth quarters of 2020. As for co-infections, the positive rate was at its lowest in 2020. In the previous 2 years, viral-MP was the most common type of mixed infection. By contrast, in 2020, viral-viral infections were the most common combination.Conclusion: The pathogen detection rate was significantly reduced in Suzhou City during the COVID-19 pandemic. Public interventions may help to prevent respiratory pathogen infections in children.

OBJECTIVES:To investigate the epidemiological characteristics of respiratory Haemophilus influenzae (HI) infection in children in Suzhou, China and its association with climatic factors and air pollutants. METHODS:The data on air pollutants and climatic factors in Suzhou from January 2016 to December 2019 were collected. Respiratory secretions were collected from 7 940 children with acute respiratory infection who were hospitalized during this period, and bacterial culture results were analyzed for the detection of HI. A stepwise regression analysis was used to investigate the association of HI detection rate with air pollutants (PM2.5, PM10, NO2, SO2, CO, and O3) and climatic factors (monthly mean temperature, monthly mean humidity, monthly total rainfall, monthly total sunshine duration, and monthly mean wind speed). RESULTS:In 2016-2019, the 4-year overall detection rate of HI was 9.26% (735/7 940) among the children in Suzhou. The children aged <1 year and 1-<3 years had a significantly higher HI detection rate than those aged ≥3 years (P<0.01). The detection rate of HI in spring was significantly higher than that in the other three seasons, and the detection rate of HI in autumn was significantly lower than that in the other three seasons (P<0.001). The multiple linear regression analysis showed that PM10 and monthly mean wind speed were independent risk factors for the detection rate of HI: the detection rate of HI was increased by 0.86% for every 10 µg/m3 increase in the concentration of PM10 and was increased by 5.64% for every 1 m/s increase in monthly mean wind speed. Air pollutants and climatic factors had a lag effect on the detection rate of HI. CONCLUSIONS:HI is an important pathogen for acute respiratory infection in children in Suzhou and is prevalent in spring. PM10 and monthly mean wind speed are independent risk factors for the detection rate of HI.

Background Programmed death-ligand 1 (PD-L1) is an important immune checkpoint inhibitor. Recent studies suggest that the PD-L1-mediated pathway may be a promising target in allergic asthma. However, the mechanism by which PD-L1 represses neutrophilic asthma (NA) remains unclear. In this study, we examined correlations between the expression of PD-L1 and the production of T helper cell type 1 (Th1), T helper cell type 2 (Th2), and T helper cell type 17 (Th17) cells in pediatric patients with NA and a mouse model. Methods The clinical samples of 26 children with asthma and 15 children with a bronchial foreign body were collected over a period of 12 months by the Children’s Hospital of Soochow University. An experimental mouse model of asthma was established to study NA. An enzyme-linked immunoassay (ELISA) was used to assess soluble PD-L1 (sPD-L1) and cytokines [e.g., interleukin (IL)-4, IL-6, interferon gamma (IFN-γ), IL-17 and granulocyte-macrophage colony-stimulating factor (GM-CSF)] in bronchoalveolar lavage fluid (BALF). Results NA patients had significantly higher levels of sPD-L1, IL-6, IL-17, and GM-CSF in their BALF than non-NA and control patients (P<0.05). In a murine model of asthma, the positive rate and fluorescence intensity of PD-L1 in the NA group and the immunoglobulin G (IgG)-treated NA group were higher than in the PD-L1 antibody (Ab)-treated NA group and the phosphate-buffered saline (PBS) control group (P<0.05). In the plasma and the BALF of the NA group and the IgG-treatment NA group, the levels of IL-17, IL-4, tumor necrosis factor alpha (TNF-α), and granulocyte colony-stimulating were higher than those in the PBS control group (P<0.05). The histopathological examination of lung tissues from all mice groups showed that a large number of inflammatory cells were found around the airway in the NA group and the IgG-treatment group. Conclusions PD-L1 may contribute to the Th17/IL-17 immune response, which is associated with neutrophilic inflammation and asthma. A PD-L1 blockade reduces pulmonary neutrophils and mucus production.

The role of long non-coding RNAs (lncRNA) in asthma remains unclear. In this study, we examined the role of long non-coding RNA taurine upregulated 1 (lncRNA TUG1) in asthma. We found that lncRNA TUG1 is one of the differentially expressed lncRNAs in the monocytes of asthmatic children and is associated with Th cell differentiation. LncRNA TUG1 and miR-29c are mainly distributed in the cytoplasm of macrophages. Our data suggested that lncRNA TUG1 increased in macrophages stimulated by House Dust Mite in a dose-dependent manner. Using loss- and gain of function strategy, we found that miR-29c might regulate Th2 cell differentiation by directly targeting co-stimulatory molecule B7-H3. Furthermore, down-regulation of lncRNA TUG1 decreased the level of GATA3 in CD4+T cells and was associated with miR-29c/B7-H3 axis. Moreover, the dual-luciferase reporter assay confirmed that lncRNA TUG1 serves as a competing endogenous RNA to sponge miR-29c. According to the rescue experiment, lncRNA TUG1 regulated Th2 cell differentiation via miR-29c. These data suggest that lncRNA TUG1 in macrophages regulates Th2 cell differentiation via miR-29c/B7-H3 axis.

Objective:To study the macrolides resistance of Mycoplasma pneumoniae(MP) in Suzhou area, and try to explore the relationship between drug resistance and refractory Mycoplasma pneumoniae pneumonia (RMPP). Methods:From a series of hospitalized children who were diagnosed as Mycoplasma pneumoniae pneumonia (MPP) from October 2013 to September 2014 in Suzhou area, 48 children were treated with Azithromycin (10 mg/kg, once a day, intravenous drip for 5-7 days), and the clinical symptoms and chest imaging were still progressing so they were clinically diagnosed as RMPP, and 34 children who were successfully treated with macrolides antibiotics (MA) were clinically diagnosed as general MPP (GMPP). MP DNA was extracted from the airway secretion of children in the two groups, and the point mutations of 2063 and 2064 of 23S rRNA were sequenced, and according to the MP 23S rRNA sequencing results, the children were divided into macrolides antibiotic resistant MP group (MRMP) and macrolides antibiotic sensitive MP group (MSMP). The clinical characteristics of the two groups were compared. Results:In the MRMP group, the incidence of RMPP was 62.2% (46/74 cases), while in MSMP group, the incidence of RMPP was 25.0% (2/8 cases). The point mutation of MP 23S rRNA had no significant effect on the occurrence of RMPP ( χ2=2.719, P=0.099). Compared with MRMP group, MSMP group presented shorter fever time and less glucocorticoid use.No significant differences between the two groups were found in chest imaging examination, as well as some laboratory results, including the total number and classification of white blood cell (WBC), C-reactive protein (CRP), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and creatine kinase isoenzyme (CK-MB). Conclusions:The fever duration of MPP lasted more than 1 week, suggesting the possibility of macrolides resistance of MP, but macrolides resistance did not aggravate the occurrence of RMPP.It is unreliable to judge the MRMP by chest imaging features and laboratory results.

目的:探讨百日咳综合征住院患儿的临床特点及影响住院危险因素，提高临床诊治水平。方法:回顾性分析2014年至2019年在苏州大学附属儿童医院呼吸科住院的489例百日咳综合征患儿的病史、症状、体征、实验室检查及病原学等资料，总结其临床特点及影响住院危险因素。结果:年龄<3个月占53.17%，3～6个月占24.13%，>6个月占22.70%。患儿均有痉挛样咳嗽，其他症状发生率依次为喘息32.11%、咳嗽后青紫7.16%、呼吸困难3.27%、咳嗽后吸气性回声2.04%。实验室检查中白细胞升高占75.05%，淋巴细胞比例升高占73.62%，CRP升高占13.29%，血小板计数升高占85.89%。病原学检测阳性率61.15%，病毒检出率为35.58%，细菌检出率为30.47%，肺炎支原体检出率为13.70%，单一病原排序前5位是鼻病毒(24.57%)、肺炎支原体(16.46%)、肺炎链球菌(10.57%)、呼吸道合胞病毒(8.85%)、流感嗜血杆菌(8.11%)；混合感染占17.79%，其中病毒混合细菌占62.07%，病毒混合肺炎支原体占19.54%，细菌混合肺炎支原体占13.79%，病毒、细菌及肺炎支原体混合占4.60%。季节以春、夏季最为多见，占73.00%，其次为秋季19.02%，冬季7.98%。住院≥14 d的患儿中重症肺炎、先天性气道发育畸形、先天性心脏病、胃扭转、喘息发生率均明显高于住院<14 d患儿，差异均有统计学意义( χ 2＝54.920、13.986、4.770、19.966、6.891， P均<0.05)。 结论:百日咳综合征多见于6个月以下患儿，以春夏季多见，痉挛样咳嗽是特征性临床表现，血常规提示以淋巴细胞为主的白细胞升高，感染病原依次是病毒、细菌和肺炎支原体，前3位病原体依次是鼻病毒、肺炎支原体和肺炎链球菌，年龄<1岁易发生混合感染。有喘息症状、病情重、有先天性气道发育异常、先天性心脏病、胃扭转是住院时间延长的危险因素。

Background：There is an increasing attention on miRNAs because of their functional effect on polarization of CD4+ T cells. This study explores the mechanism of miR-493-5p regulating Th9 cell differentiation in allergic asthma. Methods: The allergic airway inflammation is induced by Ovalbumin(OVA)in mice. CD4+ T cells from normal mice are cultured under Th9 cell conditions. IL-9 levels in mice and CD4+T cells are analyzed by RT-qPCR, ELISA, flow cytometry and western blot. The miR-493-5p levels in mice and cells are detected by RT-qPCR. The interaction between FOXO1 and miR-493-5p is predicted by TargetScan and confirmed by dual luciferase assay. The pathological state is evaluated by H&E staining and Lung resistance is measured in the allergic mice treated with miR-493-5p agomiR before stimulation. Results: The miR-493-5p expression in OVA-induced mice decreases significantly, accompanied by a significant upregulation in IL-9, IRF4 and FOXO1 expression and proportion of CD4+Th9 cells. MiR-493-5p mimic inhibits the expression of IL-9, IRF4 and FOXO1 and Th9 cell differentiation, while the inhibitor promotes these effects. MiR-493-5p mimic represses FOXO1 expression through interacting with 3’UTR of FOXO1 mRNA. The rescue experiment proves that miR-493-5p regulates the differentiation of Th9 cell and the expression of IL-9 by targeting FOXO1. In addition, we find that miR-493-5p agomiR treatment inhibits the FOXO1, IL-9 and IRF4 expression, decreases the proportion of CD4+ Th9 cells, alleviates the pathological state of lung tissue and airway hyperreactivity in OVA-induced asthma mice. Conclusions: Our study confirmed that miR-493-5p inhibited Th9 cell differentiation in allergic asthma by targeting FOXO1.