Shuxian Li

Epidemiological characteristics and meteorological factors of childhood Mycoplasma pneumoniae pneumonia in Hangzhou

BackgroundMycoplasma pneumoniae (M. pneumoniae) is an important pathogen of pediatric respiratory infections and the relation of M. pneumoniae pneumonia (MPP) with meteorological factors remains obscure. This study aims to investigate the epidemiological characteristics of childhood MPP and observe if there is a relationship between epidemiological characteristics and meteorological factors in Hangzhou.MethodsM. pneumoniae DNA in nasopharyngeal aspirates of hospitalized pneumonia children were detected by polymerase chain reaction from January 1, 2007 to December 31, 2009. The positive rates of MPP (MPP rates) in different years, seasons and ages were compared. The relationship between MPP rates and meteorological data, including mean air temperature (°C), mean relative humidity (%), monthly precipitation (mm) and raining days were analyzed.ResultsIn 14 799 pneumonia cases found from 2007 to 2009, the MPP rate was 18.5%. Altogether 1610 boys (16.9%) and 1134 girls (21.4%) suffered from MPP with a significant difference between both genders (χ2=45.68, P<0.001). In children younger than 1 year, 1–2 years, 3–6 years, and older than 7 years, the MPP rates were 9.8%, 21.1%, 44.4% and 61.6%, respectively. The MPP rates were significantly higher in older children than in younger ones (trends test χ2=46.72, P<0.001). In a descending order, the MPP rates in summer, autumn, spring, and winter were 27.8%, 23.9%, 18.0% and 11.6%, respectively (χ2=372.75, P<0.001). The MPP rates in 2007 to 2009 were 12.9%, 19.3% and 23.6%, respectively (trends test χ2=13.72, P<0.001). Of the four meteorological factors, only monthly mean air temperature was included in the multiple linear regression model (P<0.001).ConclusionsThis study showed that the MPP rate was higher in older children than in younger ones. Girls had a higher positive rate of MPP than boys. In Hangzhou, MPP was more prevalent in summer and autumn. Air temperature was the only meteorological factor affecting the prevalence of MPP.

Peripheral T lymphocyte subset imbalances in children with enterovirus 71-induced hand, foot and mouth disease

Inflammatory mediators (i.e. cytokines) play a pivotal role in the regulation of pathophysiological processes during EV71-induced hand, foot and mouth disease (HFMD). Different T cell subsets have distinct cytokine secretion profiles, and alteration in the T cell subsets frequency (imbalance) during infection leads to changed cytokine patterns. However, the effects of EV71 infection on T cell subsets were not clear. The objective of this study was to determine whether EV71-induced HFMD can be explained by the emergence of particular T-cell subsets (Th1, Th2, Tc1, Tc2, Th17, Tc17 and Treg cells) and the cytokine they produced (IFN-γ, IL-4, IL-17A and TGF-β1), as well as distinct responses to EV71 infection. We found that when compared to the control group, the percentage of Th1 and Tc1 cells was significantly higher in mild and severe HFMD group. Similar results were found in the Th1/Th2 ratio and IFN-γ levels. On the other hand, the percentage of Th17 cells and IL-17A levels were the highest in severe HFMD cases, and lowest in controls. Similar trend was also found for the Th17/Treg cell ratio. An optimal cutoff value of 2.15% for Th17 cell and 6.72 pg/ml for IL-17A provided a discriminatory value for differentiating the severity of HFMD cases by receiver operating characteristic curve analyses. These findings reveal that the Th1/Th2 and Th17/Treg imbalance exist in HFMD patients, suggesting their involvement in the pathogenesis of EV71 infection, which may have potential value as biomarkers.

Global secretome characterization of A549 human alveolar epithelial carcinoma cells during Mycoplasma pneumoniae infection

BackgroundMycoplasma pneumoniae (M. pneumoniae) is one of the major etiological agents for community-acquired pneumonia (CAP) in all age groups. The early host response to M. pneumoniae infection relies on the concerted release of proteins with various biological activities. However, no comprehensive analysis of the secretory proteins has been conducted to date regarding the host response upon M. pneumoniae infection.ResultsWe employed the liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based label-free quantitative proteomic technology to identify and characterize the members of the human alveolar epithelial carcinoma A549 cell secretome during M. pneumoniae infection. A total of 256 proteins were identified, with 113 being differentially expressed (>1.5-fold change), among which 9 were only expressed in control cells, 10 only in M. pneumoniae-treated cells, while 55 were up-regulated and 39 down-regulated by M. pneumoniae. The changed expression of some of the identified proteins was validated by RT-PCR and immunoblot analysis. Cellular localization analysis of the secretome data revealed 59.38% of the proteins were considered as “putative secretory proteins”. Functional analysis revealed that the proteins affected upon M. pneumoniae infection were mainly related to metabolic process, stress response, and immune response. We further examined the level of one up-regulated protein, IL-33, in clinical samples. The result showed that IL-33 levels were significantly higher in the plasma and bronchoalveolar lavage fluid (BALF) of M. pneumoniae pneumonia (MPP) patients.ConclusionsThe present study provided systematic information about the changes in the expression of secretory proteins during M. pneumoniae infection, which is useful for the discovery of specific biomarkers and targets for pharmacological intervention.

Cerebrospinal fluid Th1/Th2 cytokine profiles in children with enterovirus 71‐associated meningoencephalitis

Enterovirus 71 (EV71) infection can cause severe neurological complications including meningoencephalitis (ME) in some patients with hand, foot and mouth disease (HFMD). However, to date no studies have reported changes in cytokine concentrations and their correlations with clinical variables in patients with ME following EV71 infection. In this study, responses of Th1/Th2 cytokine, including IL‐2, IL‐4, IL‐6, IL‐10, TNF‐α and IFN‐γ, in cerebrospinal fluid (CSF) from patients with EV71‐related HFMD with ME and patients with febrile convulsions (FC) were analyzed using cytometric bead array technology. It was found that CSF IL‐6 and IFN‐γ concentrations were significantly higher in patients with EV71‐related ME than in those with FC. Additionally, both CSF IL‐6 and IFN‐γ concentrations were correlated with CSF cytology, fever duration and duration of hospital stay. More interestingly, a positive correlation between CSF IL‐6 and IFN‐γ concentrations was observed. Finally, receiver operating characteristic analysis revealed that when a cutoff value of 9.40 pg/mL was set for IL‐6, the sensitivity and specificity were 84.5% and 85.5%, respectively, for discriminating EV71‐related ME from FC. In conclusion, IL‐6 and IFN‐γ may be associated with EV71‐induced neuropathology.

Mycoplasma pneumoniae‐associated necrotizing pneumonitis in children

Mycoplasma pneumoniae is a major cause of communityacquired respiratory infections in children and adults. A number of severe pulmonary complications have been reported with M. pneumoniae infection. These complications include obliterative bronchitis, bronchiectasis, pleural effusion, interstitial fibrosis, lung abscess, acute respiratory distress syndrome (ARDS) and necrotizing pneumonitis. Necrotizing pneumonitis, which has been described as a suppurative complication of Streptococcus pneumoniae infection, is a rare manifestation of M. pneumoniae infection. Herein we report on five pediatric patients with necrotizing pneumonitis due to M. pneumoniae and review the relevant literature.

Tracheal diverticula in infants: a report of three cases

Tracheal diverticulum is a paratracheal air cyst in connection with the trachea. It may be congenital or acquired. Congenital tracheal diverticula in infants are rare. Imaging techniques such as high-resolution computed tomography and three-dimensional reconstruction of the airway are useful for diagnosis. Here we report three cases with congenital tracheal diverticula, which were diagnosed by imaging techniques.

Cerebrospinal fluid chemokine patterns in children with enterovirus 71-related encephalitis

Enterovirus 71 (EV71) is a major pathogen that causes hand, foot and mouth disease (HFMD) as well as neurological complications, such as encephalitis. The chemokines involved in the migration of leukocytes have increasingly been implicated in infectious diseases of the central nervous system. Few studies have evaluated the levels of chemokines in HMFD children with EV71-related encephalitis. In the present study, we evaluated the cerebrospinal fluid (CSF) levels of the chemokines IL-8, RANTES, MIG, MCP-1 and IP-10 in 99 children with EV71-related encephalitis and 22 children with febrile convulsion (FC). We found that the concentrations of IL-8, RANTES, MIG and IP-10 were significantly higher in HFMD children with encephalitis compared to patients with FC. Additionally, these four chemokines were dramatically reduced during convalescence. Inversely, the level of MCP-1 was lower in encephalitis patients than FC patients and was not significantly reduced during convalescence. Additionally, MIG was strongly correlated with IP-10 in encephalitis patients. Furthermore, the area under the ROC curve (AUC) of CSF MIG and IP-10 in distinguishing encephalitis from FC were 0.869 and 0.876, and the corresponding sensitivities/specificities were 67.7%/100.0% and 67.7%/95.5%, respectively. In conclusion, our results indicate that chemokines play important roles in the pathogenesis of EV71 infection.

The safety profile of subcutaneous allergen immunotherapy in children with asthma in Hangzhou, East China

BACKGROUND The aim of the current study is to evaluate the prevalence, severity and possible risk factors of systemic reactions (SRs) to subcutaneous allergen immunotherapy (SCIT) in children and adolescents with asthma in Hangzhou, east Chinas Zhejiang province. METHODS From January 2011 to December 2016, this survey analysed the SCIT-related SRs involving 429 patients (265 children and 134 adolescents) affected by allergic asthma. Recorded data included demographics, diagnosis, patient statuses, pulmonary function testing results before and after each injection, allergen dosage, and details of SRs. RESULTS All patients finished the initial phase and six patients withdrew during the maintenance phase. There were 2.59% (328/12,655) SRs in all injections (3.28% in children and 1.47% in adolescents); 15.62% (67/429) patients experienced SRs (18.49% children and 10.98% adolescents). There were 54.57% SRs of grade 1; 42.37% SRs of grade 2; 3.05% SRs of grade 3; and no grades 4 or grade 5 SRs occurred in patients. Most reactions were mild, and were readily controlled by immediate emergency treatment. There was no need for hospitalisation. The occurrence of SRs was significantly higher in children than that in adolescents (p<0.01). A higher ratio of SRs was found among patients with moderate asthma. CONCLUSION This retrospective survey showed that properly-conducted SCIT was a safe treatment for children and adolescents with asthma in Hangzhou, East China. Children and patients with moderate asthma may be prone to develop SRs.

Reply to "How to diagnose Mycoplasma pneumoniae etiology in a child with pneumonia"

About the question raised by Korppi [4], the diagnostic criteria for Mycoplasma pneumoniae pneumonia (MPP) were diverse. Several diagnostic methods have been used to diagnose M. pneumoniae infection, including M. pneumoniae isolation, serologic testing, and molecular-based detection assays [7]. Each of these methods had limitations including serologic testing. However, serologic testing for M. pneumoniae infection was accepted widely. In Liu’s study [5], the diagnosis of active infection with M. pneumoniae was based on an at least fourfold mycoplasma particle agglutinin titer elevation in paired sera or the presence of anti-mycoplasma IgM above the cutoff value. Serological tests were performed in a total of 140 children and paired sera were obtained from only 41 of them. In Eun’s study [1], a fourfold or greater rise in the antibody titers and/or a single titer >1:640 were considered diagnostic of M. pneumoniae infections using indirect particle agglutination test. In this paper, no figure was exactly indicated how many children were only diagnosed based on single serology. Other studies [2, 3, 6, 10] also included single-point serology as a diagnostic criteria. Yamazaki et al. [9] concluded that in unpaired sera, a PA antibody titer of 1:80 or 1:160 is useful for the serological diagnosis of M. pneumonia infection among children with LRTI. We did not do a two-phase serology test. That is a limitation. However, the main aim of our previous study [8] was to compare the diagnostic value of two different specimens, which were nasopharyngeal aspirate (NPA) and bronchoalveolar lavage (BAL) in diagnosing MPP. Therefore, other diagnostic methods should be taken as “gold standard”. We think that one-point ELISA can fulfill the demand of comparing the diagnostic value of two different specimens. Nearly a total overlapping in the 95% confidence intervals of sensitivities and specificities of PCR in NPA vs. BAL were observed [8]. Moreover, likelihood ratio positive were 2.15 and 1.70 for PCR in NPA and BAL, respectively. Likelihood ratio negative were 0.34 and 0.51 for PCR in NPA and BAL, respectively. Only minor effects existed on pretest probability. Combining with other diagnosing parameters, including sensitivity, specificity, positive prediction value and negative prediction value (see the previous article [8]), PCR in NPA and BAL had similar performance as we mentioned previously [8]. The conclusion we made that NPA was superior to BAL for diagnosing MPP was not just based on the diagnosing parameters but also on economy, clinical convenience, and less harmful for children.