Comparison of Mycoplasma pneumoniae IgM and IgE Antibody Levels in Asthmatic and Non-Asthmatic Adults

OBJECTIVE

Mycoplasma pneumoniae (M. pneumoniae), an extracellular pathogen lacking a cell wall, causes respiratory infection in adults and children and has been implicated in asthma exacerbation; immunoglobulin (Ig) E may be involved in these exacerbations. Specific IgM and IgG immune response to M. pneumoniae has been reported, but less is known about IgE M. pneumoniae antibody (Ab) responses in asthma. Previous studies in our laboratory demonstrated that asthmatic children have increased IgM M. pneumoniae levels, but not IgE. Thus, we sought to investigate whether past M. pneumoniae infection triggers production of M. pneumoniae-specific IgE Abs in adult subjects with/without asthma.

METHODS

M. pneumoniae- IgE and -IgM Ab responses were studied in adult asthmatic (N=22) and non-asthmatic (N=22) subjects (ELISA). Data are reported as antibody index. Threshold detection levels: IgE, IgM: 0.2, 0.9, respectively.

RESULTS

M. pneumoniae-IgE Ab levels were low and below the threshold of detection in both asthmatic and non-asthmatics (0.002±0.008 vs. 0.02±0.03; P=0.021). However, specific-IgM levels were slightly higher in non-asthmatics compared with asthmatics (0.96±0.37 vs. 0.79±0.31; P=0.054). M. pneumoniae-IgM Ab positivity was similar in both groups (P=1.0).

CONCLUSION

IgM M. pneumoniae Abs may play an important role in non-asthma and persist for months after acute infection. IgE M. pneumoniae Abs may play a less important role in both groups.

miR-143-3p impacts on pulmonary inflammatory factors and cell apoptosis in mice with mycoplasmal pneumonia by regulating TLR4/MyD88/NF-κB pathway

miR-143-3p is correlated with inflammatory pain responses, such as hsa-miR-143-3p expression reduction in fibromyalgia. The present study aimed to explore the effects of miR-143-3p and Toll-like receptor (TLR) 4/myeloid differentiation factor 88 (MyD88)/NF-κB signaling pathway on pulmonary inflammatory factors levels and alveolar epithelial cell apoptosis in mycoplasmal pneumonia mice. Twenty mice were selected as normal group. The 120 successfully modeled Mycoplasma pneumoniae (MP) infection mice were randomly divided into model group (without any treatment), negative control (NC) group (injected with NC mimic), miR-143-3p mimic group (injected with miR-143-3p mimic), miR-143-3p inhibitor group (injected with miR-143-3p inhibitor), TAK-242 group (treatment with TAK-242), and miR-143-3p inhibitor + TAK-242 group (treatment with miR-143-3p inhibitor + TAK-242). Compared with model group, model mice had up-regulated miR-143-3p expression and decreased MyD88 and p-NF-κB p50 protein expressions (all P<0.05); Model mice treated with miR-143-3p mimic and TAK-242 had reduced interleukin (IL)-2 and tumor necrosis factor (TNF)-α contents and protein expressions of MyD88, p-NF-κB p50, increased IL-10 content, fewer alveolar epithelial cell apoptosis, lower Bax expression and higher Bcl-2 expression (all P<0.05); however, mice with miR-143-3p inhibitor treatment showed opposite trends in terms of above indicators. The exacerbation of mycoplasmal pneumonia caused by miR-143-3p inhibitor was partly improved by miR-143-3p inhibitor + TAK-242 combination treatment (all P<0.05). Therefore, up-regulation of miR-143-3p expression may ameliorate pulmonary inflammatory factors levels and reduce alveolar epithelial cell apoptosis in mycoplasmal pneumonia mice by inhibiting TLR4/MyD88/NF-κB signaling pathway.

Immunochromatography for the diagnosis of Mycoplasma pneumoniae infection: A systematic review and meta-analysis

The aim of this study was to evaluate the diagnostic performance of immunochromatographic tests (ICTs) for the detection of Mycoplasma pneumoniae. Medline/Pubmed, Embase, the Cochrane Library, and ISI Web of Science were searched through June 12, 2019 for relevant studies that used ICTs for the detection of M. pneumoniae infection with polymerase chain reaction (PCR) or microbial culturing as reference standards. Pooled diagnostic accuracy with 95% confidence interval (CI) was calculated using a bivariate random effects model. We also constructed summary receiver operating characteristic curves and calculated the area under the curve (AUC). Statistical heterogeneity was evaluated by χ² test or Cochrane’s Q test. Thirteen studies including 2,235 samples were included in the meta-analysis. The pooled sensitivity and specificity for diagnosing M. pneumoniae infection were 0.70 (95% CI: 0.59–0.79) and 0.92 (95% CI: 0.87–0.95), respectively. The positive likelihood ratio (LR) was 8.94 (95% CI: 4.90–14.80), negative LR 0.33 (95% CI: 0.22–0.46), diagnostic odds ratio 29.20 (95% CI: 10.70–64.20), and AUC 0.904. In subgroup analysis, ICTs demonstrated similar pooled sensitivities and specificities in populations of children only and mixed populations (children + adults). Specimens obtained from oropharyngeal swabs exhibited a higher sensitivity and specificity than those of nasopharyngeal swab. Moreover, pooled estimates of sensitivity and accuracy for studies using PCR as a reference standard were higher than those using culture. The pooled sensitivity and specificity of Ribotest Mycoplasma^®, the commercial kit most commonly used in the included studies, were 0.66 and 0.89, respectively. Overall, ICT is a rapid user-friendly method for diagnosing M. pneumoniae infection with moderate sensitivity, high specificity, and high accuracy. This suggests that ICT may be useful in the diagnostic workup of M. pneumoniae infection; however, additional studies are needed for evaluating the potential impact of ICT in clinical practice.

MHC-DRB1 exon 2 polymorphism and its association with mycoplasma ovipneumonia resistance or susceptibility genotypes in sheep

Major histocompatibility complex (MHC) polymorphisms are associated with animal and human diseases. However, only a few studies have reported an association between MHC polymorphisms and mycoplasma ovipneumonia (MO). In the present study, three resistance/susceptibility genotypes associated with MO were identified by polymerase chain reaction-restriction fragment length polymorphism genotyping, assessing the clinical and pathological features, and examining the immune factors. The current results showed that MvaI bb and HaeIII ee were dominant genotypes in the susceptible Hu population, while MO-resistant populations, Dorper and D 9 H hybrids, were dominated by the MvaI cc and HaeIII dd genotypes, suggesting that MvaI cc and HaeIII dd genotypes might be associated with the trait of MO resistance. Further, the clinical symptoms and pathological morphology in the susceptibility group infected with MO were more severe than those in the resistant groups infected similarly. The data on the changes in the immune factor responses were utilized to deduce the molecular mechanism underlying the MO resistance/susceptibility. The results showed that the susceptible genotypes promote the inflammatory responses by inducing a high expression of TNFa, IFNc, IL-4, IL-6, and IL-1b, while the resistant genotypes inhibit the inflammatory response by increasing the expression of IL-2 and IL-10 significantly. This finding would provide the theoretical guidance for propagating sheep breeds that are highly resistant to MO.

Association between inflammation factors and Mycoplasma pneumoniae in children: Protocol for a systematic review

BACKGROUND

Several clinical studies have reported that inflammation factors (IF) are associated with Mycoplasma pneumoniae in children. However, no study systematically investigated the association between IF and M pneumoniae in pediatric population. Thus, this study will explore the association between IF and pediatric M pneumoniae systematically.

METHODS

This study will search following databases of PUBMED, PsycINFO, Scopus, Cochrane Library, EMBASE, Web of Science, and Chinese Biomedical Literature Database from inception to the February 28, 2019 without any language limitations. We will cover clinical studies of M pneumoniae that report associations between IF and M pneumoniae. In addition, reference lists of relevant studies will also be identified to avoid missing any eligible studies. Two investigators will independently screen and select studies, and will assess the methodological quality for each study, which is evaluated by using Newcastle Ottawa Scale. Any disagreements will be settled down through discussion with a third investigator until consensus is reached.

RESULTS

This study will explore the associations between IF and M pneumoniae by assessing the changes of IF, such as interleukin (IL)-4, IL-5, IL-6, IL-10, IL-13, and IL-17 at different stages of M pneumoniae.

CONCLUSION

The findings of this study may provide most recent evidence for the associations between IF and M pneumoniae in pediatric populations.

ETHICS AND DISSEMINATION

Ethical approval is not needed in this study, because no individual patient data will be utilized in this study. The findings of this study are expected to be published at peer-reviewed journal or will be presented at professional conference.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD42019125359.

Dietary Supplementation with Low-Molecular-Weight Fucoidan Enhances Innate and Adaptive Immune Responses and Protects against Mycoplasma pneumoniae Antigen Stimulation

In this study, the low-molecular-weight (LMW) fucoidan, rich in fucose and sulfate, was extracted and purified from the edible brown seaweed, Laminaria japonica. In this study, we orally administered LMW fucoidan to mice for 6 weeks. We then examined fucoidan's effects on innate immunity, adaptive immunity, and Mycoplasma pneumoniae (MP)-antigen-stimulated immune responses. Our data showed that LMW fucoidan stimulated the innate immune system by increasing splenocyte proliferation, natural killer (NK) cell activity, and phagocytic activity. LMW fucoidan also increased interleukin (IL)-2, IL-4, and interferon (IFN)-γ secretion by splenocytes and immunoglobulin (Ig)-G and IgA content in serum, which help regulate adaptive immune cell functions, and decreased allergen-specific IgE. In MP-antigen-stimulated immune responses, the IgM and IgG content in the serum were significantly higher in the LMW fucoidan group after MP-antigen stimulation. Our study provides further information about the immunomodulatory effects of LMW fucoidan and highlights a potential role in preventing M. pneumoniae infection.

Independent predictors for longer radiographic resolution in patients with refractory Mycoplasma pneumoniae pneumonia: a prospective cohort study

OBJECTIVES

To examine prospectively the radiographic clearance of refractory Mycoplasma pneumoniae pneumonia (RMPP) in immunocompetent children, and to identify independent predictors of time to complete radiographic resolution in patients with RMPP.

DESIGN

A prospective cohort study.

SETTING

Children's Hospital of Soochow University, China.

PARTICIPANTS

A total of 187 patients with RMPP treated with bronchoscopy were prospectively enrolled in the study between January 2012 and December 2015.

METHODS

Serial chest radiographs were obtained after discharge every 4 weeks up to a maximum of 24 weeks after diagnosis or until large infiltration on chest radiographs had resolved. Multivariate logistic regression was performed to identify independent predictors of time to complete radiographic resolution.

RESULTS

Of the 187 patients with RMPP, bronchial mucus plug formation was detected in 73 (39.0%). C reactive protein (CRP) ≥50 mg/L, lactate dehydrogenase (LDH) ≥480 U/L, total fever duration ≥10 days and presence of mucus plugs were associated with longer time to radiographic clearance (all p<0.01). Compared with children without mucus plugs, those with mucus plugs were significantly more likely to have longer time to radiographic clearance (adjusted OR: 11.5; 95% CI 2.5 to 45.7; p<0.01).

CONCLUSION

Clinicians might use duration of fever, CRP, LDH and presence of mucus plugs as parameters to identify children at a longer time to radiographic clearance in patients with RMPP.

Increased Total Serum Immunoglobulin E in Children Developing Mycoplasma pneumoniae-related Extra-pulmonary Diseases

Mycoplasma pneumoniae has been recognized to be involved in several extra-pulmonary diseases, but the underlying immunologic mechanisms are still largely unknown. Recently, we observed a significant elevation of serum Immunoglobulin E (IgE) in a small group of these children. Here, we assessed total serum IgE levels in children affected with Mycoplasma pneumoniae-related extra-pulmonary diseases. We prospectively collected the data of 162 children admitted to the hospital (because of respiratory infections or extra-pulmonary diseases) who were evaluated for Mycoplasma pneumoniae serology and total serum IgE levels, concomitantly. Based upon clinical and serology aspects, 3 groups of children were identified: I) with non-mycoplasma respiratory disease; II) with mycoplasma-related respiratory diseases; III) with extra-pulmonary diseases related to concomitant/recent Mycoplasma pneumoniae infection. Interestingly, children with Mycoplasma pneumoniae-related extra-pulmonary diseases showed a significant elevation of total serum IgE. In particular, patients developing Mycoplasma pneumoniae-related extra-pulmonary diseases (group III) showed significantly higher level of IgE than both previous groups (p<0.001 vs. group I; p<0.01 vs. group II). In conclusion, hospitalized children diagnosed with Mycoplasma pneumoniae-related extra-pulmonary diseases resulted to have significantly increased serum IgE compared to children developing respiratory illnesses only.

[Effects of Huaiqihuang granules on immune function in children with severe Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To observe the effects of Huaiqihuang granules on the immune function in children with severe Mycoplasma pneumoniae pneumonia.

METHODS

Pediatric inpatients with severe Mycoplasma pneumoniae pneumonia were randomly divided into Huaiqihuang granule treatment group (n=51) and conventional treatment group (n=47). The Huaiqihuang granule treatment group was orally administered Huaiqihuang granules in addition to the conventional treatment, while the conventional treatment group received conventional treatment only. Levels of serum IgA, IgG, and IgM, percentages of CD4+ and CD8+ T lymphocyte subsets, and CD4+/CD8+ ratio were examined in the two groups. The incidence rate of respiratory tract re-infection within three months following treatment was compared between the two groups.

RESULTS

The levels of serum IgA, IgG, and IgM, the percentage of CD4+ T lymphocytes, and the CD4+/CD8+ ratio were significantly higher in the Huaiqihuang granule treatment group than in the conventional treatment group three months after treatment (P<0.05). In contrast, the percentage of CD8+ T lymphocytes was significantly lower in the Huaiqihuang granule treatment group than in the conventional treatment group (P<0.05). In addition, the incidence rate of respiratory tract re-infection within three months following treatment was significantly lower in the Huaiqihuang granule treatment group than in the conventional treatment group (P<0.05).

CONCLUSIONS

Huaiqihuang granules can regulate immune functions and reduce the incidence of short-term respiratory tract re-infection in children with severe Mycoplasma pneumoniae pneumonia.

[Effects of Huaiqihuang granules on immune function in children with severe Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To observe the effects of Huaiqihuang granules on the immune function in children with severe Mycoplasma pneumoniae pneumonia.

METHODS

Pediatric inpatients with severe Mycoplasma pneumoniae pneumonia were randomly divided into Huaiqihuang granule treatment group (n=51) and conventional treatment group (n=47). The Huaiqihuang granule treatment group was orally administered Huaiqihuang granules in addition to the conventional treatment, while the conventional treatment group received conventional treatment only. Levels of serum IgA, IgG, and IgM, percentages of CD4⁺ and CD8⁺ T lymphocyte subsets, and CD4⁺/CD8⁺ ratio were examined in the two groups. The incidence rate of respiratory tract re-infection within three months following treatment was compared between the two groups.

RESULTS

The levels of serum IgA, IgG, and IgM, the percentage of CD4⁺ T lymphocytes, and the CD4⁺/CD8⁺ ratio were significantly higher in the Huaiqihuang granule treatment group than in the conventional treatment group three months after treatment (P<0.05). In contrast, the percentage of CD8⁺ T lymphocytes was significantly lower in the Huaiqihuang granule treatment group than in the conventional treatment group (P<0.05). In addition, the incidence rate of respiratory tract re-infection within three months following treatment was significantly lower in the Huaiqihuang granule treatment group than in the conventional treatment group (P<0.05).

CONCLUSIONS

Huaiqihuang granules can regulate immune functions and reduce the incidence of short-term respiratory tract re-infection in children with severe Mycoplasma pneumoniae pneumonia.

[Association of T lymphocyte subsets and allergens with Mycoplasma pneumoniae infection complicated by wheezing in infants and young children]

OBJECTIVE

To investigate the percentage of T lymphocyte subsets and allergen screening results in infants and young children with Mycoplasma pneumoniae (MP) infection complicated by wheezing.

METHODS

Flow cytometry was used to measure the percentage of peripheral blood T cell subsets in 354 infants and young children with MP infection complicated by wheezing (MP wheezing group), 336 infants and young children with MP infection but without wheezing (MP non-wheezing group), and 277 children with recurrent wheezing (recurrent wheezing group). Allergen screening was also performed for these children.

RESULTS

Both the MP wheezing group and recurrent wheezing group had significantly lower percentages of CD3⁺ and CD3⁺CD8⁺ lymphocytes than the MP non-wheezing group (p<0.05). The MP groups with or without wheezing had a significantly higher percentage of CD3⁺CD4⁺ lymphocytes than the recurrent wheezing group (p<0.05). Both the MP wheezing group and recurrent wheezing group had significantly higher percentages of CD3^-CD19⁺ and CD19⁺CD23⁺ lymphocytes than the MP non-wheezing group (p<0.05), and the recurrent wheezing group had the highest percentages (p<0.05). The overall positive rate of food allergens was significantly higher than that of inhaled allergens (30.3% vs 14.7%; p<0.05). The positive rates of food and inhaled allergens in the recurrent wheezing group and MP wheezing group were significantly higher than in the MP non-wheezing group (p<0.05), and the recurrent wheezing group had the highest rates.

CONCLUSIONS

Imbalance of T lymphocyte subsets and allergic constitution play important roles in the pathogenesis of MP infection complicated by wheezing in infants and young children.

CYP1A1 mediates the suppression of major inflammatory cytokines in pulmonary alveolar macrophage (PAM) cell lines caused by Mycoplasma hyponeumoniae

Mycoplasmal pneumonia is a lung infection disease caused by Mycoplasma hyopneumoniae in swine. We previously reported that Cytochrome P450 1A1 (CYP1A1) expression was significantly downregulated in pigs infected with M. hyopneumoniae compared to the healthy controls. In this study, pulmonary alveolar macrophage (PAM) cell lines with CYP1A1 overexpression or siRNA-mediated CYP1A1 silencing were used to explore the biological function and regulatory mechanism of CYP1A1 gene expression changed on the inflammatory response of pigs infected with M. hyopneumoniae. The results showed that the cells overexpressing CYP1A1 infected with M. hyopneumoniae led to a rapid increase in PPAR-γ expression, which resulted in decreasing the levels of several inflammatory cytokines including IL-1β, IL-6, IL-8 and TNF-α. On the contrary, this effect was just opposite in CYP1A1-RNAi cells infected with M. hyopneumoniae. We suggest that CYP1A1 suppress the inflammatory response caused by M. hyopneumoniae infection, via PPAR-γ signaling pathway in pigs.

Elongation Factor Tu and Heat Shock Protein 70 Are Membrane-Associated Proteins from Mycoplasma ovipneumoniae Capable of Inducing Strong Immune Response in Mice

Chronic non-progressive pneumonia, a disease that has become a worldwide epidemic has caused considerable loss to sheep industry. Mycoplasma ovipneumoniae (M. ovipneumoniae) is the causative agent of interstitial pneumonia in sheep, goat and bighorn. We here have identified by immunogold and immunoblotting that elongation factor Tu (EF-Tu) and heat shock protein 70 (HSP 70) are membrane-associated proteins on M. ovipneumonaiea. We have evaluated the humoral and cellular immune responses in vivo by immunizing BALB/c mice with both purified recombinant proteins rEF-Tu and rHSP70. The sera of both rEF-Tu and rHSP70 treated BALB/c mice demonstrated increased levels of IgG, IFN-γ, TNF-α, IL-12(p70), IL-4, IL-5 and IL-6. In addition, ELISPOT assay showed significant increase in IFN-γ⁺ secreting lymphocytes in the rHSP70 group when compared to other groups. Collectively our study reveals that rHSP70 induces a significantly better cellular immune response in mice, and may act as a Th1 cytokine-like adjuvant in immune response induction. Finally, growth inhibition test (GIT) of M. ovipneumoniae strain Y98 showed that sera from rHSP70 or rEF-Tu-immunized mice inhibited in vitro growth of M. ovipneumoniae. Our data strongly suggest that EF-Tu and HSP70 of M. ovipneumoniae are membrane-associated proteins capable of inducing antibody production, and cytokine secretion. Therefore, these two proteins may be potential candidates for vaccine development against M. ovipneumoniae infection in sheep.

The role of the PM2.5-associated metals in pathogenesis of child Mycoplasma Pneumoniae infections: a systematic review

The peak occurrence of Mycoplasma pneumoniae (M. pneumoniae) infections in childhood and haze episodes is concurrent. Together, the prevalence of macrolide-resistant M. pneumoniae varies among countries might also be related to the concentration of ambient fine particulate mass (aerodynamic diameter ≤2.5 μm, PM2.5). Numerous cohort studies have identified consistent associations between ambient PM2.5 and cardiorespiratory morbidity and mortality. PM2.5 is a carrier of the heavy metals. The relationship between PM2.5-associated metals and M. pneumoniae infections in childhood has been increasingly drawing public attention. First, we reviewed original articles and review papers in Pubmed and Web of Science regarding M. pneumoniae and PM2.5-associated metal and analyzed the structural basis of PM2.5-associated metal interaction with M. pneumoniae. Then, the possible mechanisms of action between them were conjectured. Mechanisms of oxidative stress induction and modulation of the host immune system and inflammatory responses via Toll-like receptors (TLRs) and/or the nuclear factor-kappa B (NF-κB) pathway are postulated to be the result of PM2.5-associated metal complex interaction with M. pneumoniae. In addition, a heavy metal effect on M. pneumoniae-expressed community-acquired respiratory distress syndrome (CARDS) toxin, and activation of the aryl hydrocarbon receptor (AhR) and TLRs to induce the differentiation of T helper (Th) cells are also regarded as important reasons for the influence of the heavy metals on the severity of M. pneumoniae pneumonia and the initial onset and exacerbation of M. pneumoniae associated asthma. PM2.5-associated metals via complex mechanisms can exert a great impact on the host through interaction with M. pneumoniae.

Regulatory CD4+CD25+ T Cells Dampen Inflammatory Disease in Murine Mycoplasma Pneumonia and Promote IL-17 and IFN-γ Responses

Mycoplasmas cause respiratory diseases characterized by persistent infection and chronic airway inflammation. Mycoplasma lung disease is immunopathologic, with CD4⁺ Th cells determining both disease severity and resistance to infection. Th2 cell responses promote immunopathology, while Th1 cells confer resistance to infection. However, regulatory CD4⁺ T cells may also have a role in the pathogenesis of mycoplasma respiratory diseases. We hypothesized Treg cells control the severity of the inflammatory lesions and may also promote persistence of infection. To examine this, BALB/c mice were depleted of CD25⁺ cells, and had increased disease severity due to Mycoplasma pulmonis infection. Increases in mycoplasma antibody responses and lymphocyte infiltration into lungs also occurred after CD25⁺ cell depletion. CD4⁺CD25⁺ regulatory T cells promoted IFN-γ and IL-17 mycoplasma-specific CD4⁺ T cell responses in vitro and in vivo, while dampening IL-13⁺ Th responses. Neither IL-10 nor TGF-ß expression was detected in CD4⁺CD25⁺ T cells from lymph nodes. Thus, a regulatory T cell population plays an important role in controlling damaging immune responses in mycoplasma respiratory disease but does not contribute to persistence of infection. It appears that a regulatory T cell population preferentially dampens Th2 cell-mediated inflammatory responses to mycoplasma through a mechanism independent of IL-10 or TGF-ß characteristic of “classic” Treg cells.

Early Serologic Diagnosis of Mycoplasma pneumoniae Pneumonia: An Observational Study on Changes in Titers of Specific-IgM Antibodies and Cold Agglutinins

There have been some limitations on early diagnosis of Mycoplasma pneumoniae (MP) infection because of no immunoglobulin M (IgM) responses and variable detection rates of polymerase chain reaction in the early stage of the disease. We wanted to discuss regarding early diagnostic method using short-term paired titration of MP-specific IgM and cold agglutinins (CAs) in the early stage of MP pneumonia.The participants of this study were 418 children with MP pneumonia during 2 recent epidemics (2006-2007 and 2011), and they were diagnosed by an anti-MP IgM antibody test (Serodia Myco II) examined twice during hospitalization at presentation and around discharge (mean of 3.4 ± 1.3 days apart). CA titers were simultaneously examined twice during study period. Anti-MP IgM antibody titer ≥1:40 and CA titer ≥1:4 were considered positive, respectively. The relationships between 2 IgM antibodies in the early stage were evaluated.Regarding MP-specific antibody titers, 148 patients showed a seroconversion, 245 patients exhibited increased titers, and 25 patients had unchanged higher titers (≥1:640) during hospitalization. The median MP-specific antibody titers at each examination time were 1:80 and 1:640, respectively; those of CAs were 1:8 and 1:32, respectively. Illness duration prior to admission showed a trend of association with both titers, and patients with shorter illness duration had a higher rate of negative titers or lower titers at each examination time. CAs and MP-specific antibody titers were correlated in the total patients at presentation and at 2nd examination (P < 0.001, respectively), and the diagnostic corresponding rates of CAs to IgM antibody test were 81% to 96% in patient subgroups.Short-term paired MP specific-IgM determinations in the acute stage may be used as a definitive diagnostic method for MP pneumonia. Paired CA titers showed a correlation with MP-specific antibody titers, suggesting they can be used as an adjuvant diagnostic method.

Role of anti-inflammatory cytokines in pathogenesis of pediatric mycoplasma pneumoniae pneumonia

Through detection and analysis of the changes of interleukin (IL)-2 and IL-10 in children with mycoplasma pneumoniae pneumonia (MPP), this study aimed to explore the role of cytokines in the pathogenesis of pediatric MPP as well as immunological pathogenesis of MPP, to provide guidance for clinical diagnosis, assessment and treatment of MPP. Enzyme linked immunosorbent adsorption (ELISA) analysis was applied to determine the expression level of IL-2 and IL-10 in serum. According to the experimental results, we found that the expression levels of IL-2 and IL-10 changed significantly in different phases of MPP in comparison with a healthy control group and a case control group. The expression levels of IL-2 and IL-10 can be used as an important indicator for early diagnosis of MPP. Accordingly, detection of IL-2 and IL-10 is of great significance to the diagnosis of MPP and studies on their roles can provide guidance for treatment.

Decreased Interleukin-10 Responses in Children with Severe Mycoplasma pneumoniae Pneumonia

Several cytokines may play roles in the immunological pathogenesis of mycoplasmal pneumonia caused by Mycoplasma pneumoniae. In this study, we investigated serum cytokine profiles in children with mycoplasmal pneumonia. The serum levels of interleukin (IL)-8, IL-10, and IL-18 were examined using ELISA kits in 34 patients with M. pneumoniae infection (Group 1, 11 with severe mycoplasmal pneumonia; Group 2, 13 with mild mycoplasmal pneumonia; Group 3, 10 with asthma) and 32 age-matched, non-infected controls. The serum levels of IL-8, IL-10, and IL-18 increased significantly in patients with mycoplasmal pneumonia compared with those in controls (P<0.01). The serum levels of IL-10 decreased significantly in Group 1 compared with those in Group 2 (P<0.01). The serum levels of IL-18 increased significantly in Group 1 compared with those in Group 2 (P<0.01). The serum levels of IL-10 and IL-18 decreased significantly in 10 M. pneumoniae-infected patients with asthma compared with those in 24 M. pneumoniae-infected patients without asthma (P<0.01). We examined the level of interleukins (IL-8, IL-10 and IL-18) after the patients started therapy. The data showed that IL-18 were lower after therapy (P<0.01). Collectively, our data suggested that these cytokines may be involved in the pathogenesis of mycoplasmal pneumonia.

Rapid diagnosis of Mycoplasma pneumoniae in children with pneumonia by an immuno-chromatographic antigen assay

Mycoplasma pneumoniae is a particularly important pathogen that causes community acquired pneumonia in children. In this study, a rapid test was developed to diagnose M. pneumoniae by using a colloidal gold-based immuno-chromatographic assay which targets a region of the P1 gene. 302 specimens were analyzed by the colloidal gold assay in parallel with real-time PCR. Interestingly, the colloidal gold assay allowed M. pneumoniae identification, with a detection limit of 1 × 10(3) copies/ml. 76 samples were found to be positive in both real-time PCR and the colloidal gold assay; two specimens positive in real-time PCR were negative in the rapid colloidal gold assay. The specificity and sensitivity of the colloidal gold assay were 100% and 97.4%, respectively. These findings indicate that the newly developed immuno-chromatographic antigen assay is a rapid, sensitive and specific method for identifying M. pneumoniae, with potential clinical application in the early diagnosis of Mycoplasma pneumoniae infection.

The determinant of periodicity in Mycoplasma pneumoniae incidence: an insight from mathematical modelling

Until the early 1990 s, incidences of Mycoplasma pneumoniae (MP) infection showed three to five year epidemic cycles in multiple countries, however, the mechanism for the MP epidemic cycle has not been understood. Here, we investigate the determinant of periodicity in MP incidence by employing a mathematical model describing MP transmission dynamics. Three candidates for the determinant of periodicity were evaluated: school-term forcing, minor variance in the duration of immunity, and epidemiological interference between MP serotypes. We find that minor variation in the duration of immunity at the population level must be considered essential for the MP epidemic cycle because the MP cyclic incidence pattern did not replicate without it. Minor variation, in this case, is a less dispersed distribution for the duration of immunity than an exponential distribution. Various lengths of epidemic cycles, including cycles typically found in nature, e.g. three to five year cycles, were also observed when there was minor variance in the duration of immunity. The cyclic incidence pattern is robust even if there is epidemiological interference due to cross-immune protection, which is observed in the epidemiological data as negative correlation between epidemics per MP serotype.

Changes in levels of IL-9, IL-17, IFN-γ, dendritic cell numbers and TLR expression in peripheral blood in asthmatic children with Mycoplasma pneumoniae infection

Mycoplasma pneumoniae (MP) infection in children with asthma resulted in a more severe allergic state compared with a non-MP infected group. The infection rate of children with asthma was higher than that of the other groups, suggesting that being asthmatic may be a predisposing factor for MP infection and that the infection itself is an important co-factor in the disease progression of asthma. The number of dendritic cells (DCs) and the expression of TLR2 and TLR4 were compared in 22 asthmatic patients with MP infection, 22 asthmatic patients without MP infection, and 17 normal children as controls. The percentages of DCs in the peripheral blood of the three groups showed significant differences between asthmatic children with MP infection and controls, and asthmatic children without MP and controls (P<0.05), whereas no difference was found between asthmatic children with and without MP infection. The asthmatic children with MP infection group showed increased expression of TLR-2 and TLR-4 on DCs (P<0.01). Asthmatic patients infected with MP showed that DCs and TLRs (TLR-2, TLR-4) might play an important role in asthma pathogenesis with MP infection. The cytokines produced by the T-cell subsets in asthmatic children with MP infection showed a significant increase in IL-9 (P<0.01) and a decrease in IFN-γ (P<0.05) levels post-MP infection, while the IL-17 level remained stable (P>0.05), indicating a shift towards Th1/Th9 in the presence of MP infection.

[Determination of Th9 cells and IL-9 in children with Mycoplasma pneumoniae infection]

OBJECTIVE

To investigate the clinical significance of T helper type 9 (Th9) cells and interleukin-9 (IL-9) in children suffering from Mycoplasma pneumoniae (MP) infection.

METHODS

A total of 86 children who were diagnosed with MP infection between January 2013 and June 2014 were classified into upper respiratory infection (URI) group (n=29), mild MP pneumonia (MPP) group (n=32) and severe MPP group (n=25). Twenty-eight healthy children were used as the control group. Peripheral blood mononuclear cells were isolated by Ficoll density gradient centrifugation, and the percentage of Th9 cells in peripheral blood was measured by flow cytometry. Serum IL-9 level was determined using ELISA.

RESULTS

The URI, mild MPP, and severe MPP groups had significantly higher percentages of Th9 cells and IL-9 levels than the control group (P<0.05); the mild MPP and severe MPP groups had significantly higher percentages of Th9 cells and IL-9 levels than the URI group (P<0.05), and the two indices were significantly higher in the severe MPP group than in the mild MPP group (P<0.01).

CONCLUSIONS

Children with MP infection have an elevated percentage of Th9 cells and IL-9 expression, both of which are positively correlated with the severity of the disease. It can be predicted that Th9 cells and IL-9 can be used as evaluation indicators for the progression and outcome of children with MP infection.

Diagnostic sensitivity of a rapid antigen test for the detection of Mycoplasma pneumoniae: Comparison with real-time PCR

A rapid antigen kit for the detection of the Mycoplasma pneumoniae ribosomal protein L7/L12 using an immunochromatographic assay, Ribotest Mycoplasma, became available in Japan in 2013. To determine the sensitivity of Ribotest compared with real-time polymerase chain reaction (PCR), we prospectively performed these two tests simultaneously in adolescent and adult patients with community-acquired pneumonia (CAP). In addition, we retrospectively analyzed the theoretical sensitivity of Ribotest using M. pneumoniae PCR-positive specimens from previous studies. In prospective study, 118 CAP cases were enrolled, and 16 cases were diagnosed as M. pneumoniae pneumonia; eight cases were PCR-positive, one case was culture positive, and all cases demonstrated a four-fold increase in antibody titer. Ribotest was positive in 15 cases; five cases were PCR positive and 10 cases were PCR negative. For the PCR was control test, the sensitivity, specificity, and overall agreement with Ribotest were 62.5%, 90.9%, and 88.9%, respectively. In the retrospective study, we used 1110 M. pneumoniae PCR-positive specimens, which are collected from pediatric patients with respiratory tract infection who visited 65 institutions throughout Japan. Using a cut-off level for the Ribotest of 8.3 × 10(4) copy/mL in transport medium, 667 (60.0%) specimens were theoretically positive. In conclusion, our prospective and retrospective results demonstrated that the diagnostic sensitivity of Ribotest compared with PCR was not high, at approximately 60%. Thus, treatment decisions about M. pneumoniae pneumonia should be based on clinical findings such as Japanese Respiratory Society scoring system and not on Ribotest results alone.

[Etiologic deciphering of community-acquired pneumonia caused by mycoplasma pneumoniae]

AIM

Use of a complex of methods for etiologic deciphering of an acute respiratory infection.

MATERIALS AND METHODS

Clinical samples of blood sera, nasopharynx washes and sputum were obtained from 35 patients with acute respiratory disease (ARD). "Difco PPLO Broth" was used for M. pneumoniae cultivation. AHR, IFR, PCR, IFA were used in the study.

RESULTS

Results of the study have shown that M. pneumoniae antigens in blood, sera samples were detected in AHR in 32 patients, and specific G and M class antibodies--in 21 and 18 cases, respectively. Simultaneous detection of IgG and IgM was registered in 14 patients. M. pneumoniae cell DNA was detected in 10 of 20 blood sera samples. Circulating immune complexes were isolated from blood sera of 8 patients (4 with pneumonia, 4 with ARD) and M. pneumoniae antigens were detected in them by using direct-IFR. IFR study of sputum and nasopharynx smears has shown that M. pneumoniae antigens were detected in 29 of 35 samples. In 12 of 15 smear samples M. pneumoniae. DNA was detected by PCR. In 10 cases results of antigen detection by IFR as well as DNA in PCR coincided. Results of analysis of all the clinical material have shown that in 33 of 35 patients positive results coincided for 2 or 3 and in some cases 4 of the laboratory study methods used.

CONCLUSION

The use of diagnostic test complex significantly increases the accuracy of the study results, and detection of specific antibodies allows to determine disease period.

[Serum tumor necrosis factor-&alpha;, interleukin -6 and galctin-3 concentrations in children with Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To study the changes in serum tumor necrosis factor-&alpha; (TNF- &alpha;), interleukin-6 (IL-6) and galctin-3 (Gal-3) concentrations in children with Mycoplasma pneumoniae pneumonia (MPP), and their roles in MPP.

METHODS

Serum TNF-&alpha;, IL-6 and Gal-3 concentrations were measured using double antibody sandwich ELISA in 48 children with acute MPP (severe: 21 cases; mild: 27 cases) and in 30 healthy children (control group).

RESULTS

Serum concentrations of TNF-&alpha;, IL-6 and Gal-3 in both the severe and mild groups were significantly higher than in the control group before treatment. The concentrations of the three indexes in the severe group were significantly higher than in the mild group. Serum concentrations of the three indexes decreased significantly after treatment in both groups.

CONCLUSIONS

Serum TNF-&alpha;, IL-6 and Gal-3 play important roles in the occurrence and development of pediatric MPP and their levels are associated the severity of this disorder.

[Clinical efficacy of adjuvant therapy with glucocorticoids in children with lobar pneumonia caused by Mycoplasma pneumoniae]

OBJECTIVE

To study the clinical efficacy of adjuvant therapy with glucocorticoids in children with lobar pneumonia caused by Mycoplasma pneumoniae.

METHODS

One hundred and eight children with lobar pneumonia caused by Mycoplasma pneumoniae were randomly divided into routine treatment and hormone treatment groups. Both groups were treated with azithromycin and other symptomatic therapies. In addition to the basic treatment, the hormone treatment group was given dexamethasone 0.25-0.3 mg/(kg·d) by intravenous drip until the body temperature was normal. Then given oral prednisone tablets 0.5-1 mg/(kg·d) (gradually reduced) for a total treatment course of 7-10 days. Before and after treatment pulmonary functions were examined, and serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), interleukin-2 (IL-2) and interleukin-6 (IL-6) were measured.

RESULTS

The duration of fever, cough relief time and pulmonary shadow absorption time on chest X-ray were significantly shorter in the hormone treatment group than in the routine treatment group (P<0.05). After treatment, the two groups showed improvements in serum CRP, ESR, IL-2, and IL-6 (P<0.05), but the hormone treatment group showed significantly more improvement (P<0.05). Varying degrees of mixed ventilation dysfunction were seen in the two groups before treatment, and hormone therapy significantly improved pulmonary function, especially promoting the recovery of small airway function.

CONCLUSIONS

Adjuvant therapy with glucocorticoids can effectively alleviate clinical symptoms, promote the absorption of pulmonary inflammation, and improve pulmonary function in children with lobar pneumonia caused by Mycoplasma pneumoniae.

[Effect of Mycoplasma pneumoniae infection on function of T lymphocytes in bronchoalveolar lavage fluid of asthmatic children]

OBJECTIVE

To investigate the effect of Mycoplasma pneumoniae (MP) infection on the function of T lymphocytes in the bronchoalveolar lavage fluid (BALF) of asthmatic children in acute and stable periods and the relationship between MP infection and asthma.

METHODS

Seventy-one hospitalized children (with bronchitis, pneumonia, and asthma) were divided into non-MP infection control group (group A, pneumonia and bronchitis without MP infection), non-MP infection asthma group (group B), and MP infection asthma group (group C). Flow cytometry was used to determine CD3(+), CD4(+), and CD8(+) T cell counts and CD4(+)/CD8(+) ratio in BALF among all children in acute and stable periods.

RESULTS

Compared with group A, groups B and C showed significant differences in CD3(+), CD4(+), and CD8(+) T cell counts and CD4(+)/CD8(+) ratio (P<0.05) in acute and stable periods, had decreased CD3(+) and CD4(+) T cell counts, an increased CD8(+) T cell count, and a significantly decreased CD4(+)/CD8(+) ratio (P<0.05) in the acute period, and had decreased CD3(+) and CD4(+) T cell counts and CD4(+)/CD8(+) ratio and an increased CD8(+) T cell count (P<0.05) in the stable period. Compared with group B, group C had significantly decreased CD3(+) and CD4(+) T cell counts and CD4(+)/CD8(+) ratio (P<0.05) and a significantly increased CD8(+) T cell count (P<0.05) in the acute period and showed no significant differences in CD3(+), CD4(+), and CD8(+) T cell counts (P>0.05) and a significant decrease in CD4(+)/CD8(+) ratio (P<0.05) in the stable period.

CONCLUSIONS

The immunological function of T lymphocytes in the airway declines significantly among asthmatic children with MP infection in acute and stable periods, leading to immue system disorder. MP may be associated with the pathogenesis of asthma.

[Effect of low-dose methylprednisolone on serum TNF-α level in children with Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To investigate the effect of low-dose methylprednisolone on serum tumor necrosis factor alpha (TNF-α) level in children with Mycoplasma pneumoniae pneumonia (MPP).

METHODS

A case-control study was conducted among 38 children with MPP who received treatment in the Affiliated Hospital of Yan'an University between January and December 2012, and who had not received glucocorticoids before hospitalization. They were randomly divided into methylprednisolone treatment (n=20) and conventional treatment groups (n=18). The methylprednisolone treatment group was administered with methylprednisolone (1 mg/kg·d) by intravenous drip for three days in addition to conventional treatment. Serum samples were collected from both groups before treatment and on days 4 and 7 of treatment. Twenty-five children who underwent physical examination in the healthcare clinic during the same period were randomly selected as a normal control group, and serum samples were collected on the same day that the physical examination was performed. Serum TNF-α levels in the three groups were measured using enzyme-linked immunosorbent assay.

RESULTS

On admission, the methylprednisolone treatment and conventional treatment groups had significantly higher serum TNF-α levels than the normal control group (P<0.01), but there was no significant difference between the methylprednisolone treatment and conventional treatment groups. On days 4 and 7 of treatment, the methylprednisolone treatment group had significantly lower serum TNF-α levels than the conventional treatment group (P<0.05; P<0.01). On day 7 of treatment, there was no significant difference in serum TNF-α level between the methylprednisolone treatment and normal control groups, but the conventional treatment group still had a significantly higher serum TNF-α level than the normal control group (P<0.01).

CONCLUSIONS

Low-dose methylprednisolone can significantly decrease serum TNF-α level and inhibit inflammatory response in children with MPP, and may reduce damage caused by inflammatory response.

Mycoplasma pneumoniae extract induces an IL-17-associated inflammatory reaction in murine lung: implication for mycoplasmal pneumonia

Mycoplasma pneumoniae (Mp) may cause immune cell reactions as pivotal aspects of this clinically common respiratory pathogen. Our aim is to determine if Mp extract induces a cellular immune response associated with interleukin (IL)-17, leading to lung inflammation and lung injury. BALB/c mice were immunized with Mp extract intraperitoneally followed by its intratracheal administration, to mimic repeated Mp infection found in humans (repeated inoculation, RI group). Those with a single inoculation were compared as single inoculation group (SI group). Analysis of bronchoalveolar lavage fluid (BALF) demonstrated that keratinocyte-derived cytokine, tumor necrosis factor-α, and IL-6 were produced and peaked on days 0.5 or 1, followed by IL-17 on day 2. Levels of these mediators in BALF were higher in RI group than SI group (P < 0.05). Further, significantly more neutrophils were recruited to the lungs of the RI group (P < 0.05). These observations suggest that IL-17 is involved in the prolonged induction of neutrophils in mice treated with Mp extract.

[Protective immune responses induced by intranasal immunization with Mycoplasma pneumoniae P1C-IL-2 fusion DNA vaccine in mice]

OBJECTIVE

To investigate the immune responses and immune protections of a DNA vaccine constructed by fusing Mycoplasma pneumoniae (M. pneumoniae) p1 gene car boxy terminal region (p1c gene) with interleukin-2 (IL-2) gene.

METHODS

BALB/c mice were immunized by intranasal inoculation of P1C-IL-2 fusion DNA vaccine. Levels of serum IgG, IgG isotypes, BAL fluids IgA, IFN-γ and IL-4 were detected by ELISA. We established the mouse models infected with M. pneumoniae, and then observed the histopathological changes in lungs and counted colonies in bronchoalveolar lavage fluid (BALF) after challenged intranasally with M. pneumoniae.

RESULTS

Serum total IgG, IgG1 and IgG2a isotypes, levels of IFN-γ and IL-4 in BALF increased significantly in the group inoculated with P1C-IL-2 fusion DNA vaccine as compared with the one with P1C DNA vaccine (P<0.05), while there was no significant difference in BALF IgA between the two groups (P>0.05). The lung tissue inflammation was aggravated and the histopathologic score (HPS) of P1C-IL-2 DNA vaccine immunized mice significantly increased as compared with those in P1C DNA vaccine immunized mice at 1, 3, 6 d after challenged intranasally with M. pneumoniae (P<0.05). The P1C-IL-2 fusion DNA vaccine did not show significant difference from P1C DNA vaccine in the detectable number of M. pneumoniae strain in BALF(P>0.05).

CONCLUSION

IL-2 can enhance the systemic immune responses of P1C DNA vaccine, but it also can develop a severe histopathological change in early days after infection of M. pneumoniae.

Dendritic cells are the major antigen presenting cells in inflammatory lesions of murine Mycoplasma respiratory disease

Mycoplasmas cause chronic respiratory diseases in animals and humans, and to date, development of vaccines have been problematic. Using a murine model of mycoplasma pneumonia, lymphocyte responses, specifically T cells, were shown to confer protection as well as promote immunopathology in mycoplasma disease. Because T cells play such a critical role, it is important to define the role of antigen presenting cells (APC) as these cells may influence either exacerbation of mycoplasma disease pathogenesis or enhancement of protective immunity. The roles of APC, such as dendritic cells and/or macrophages, and their ability to modulate adaptive immunity in mycoplasma disease are currently unknown. Therefore, the purpose of this study was to identify individual pulmonary APC populations that may contribute to the activation of T cell responses during mycoplasma disease pathogenesis. The present study indeed demonstrates increasing numbers of CD11c⁻ F4/80⁺ cells, which contain macrophages, and more mature/activated CD11c⁺ F4/80⁻ cells, containing DC, in the lungs after infection. CD11c⁻ F4/80⁺ macrophage-enriched cells and CD11c⁺ F4/80⁻ dendritic cell-enriched populations showed different patterns of cytokine mRNA expression, supporting the idea that these cells have different impacts on immunity in response to infection. In fact, DC containing CD11c⁺ F4/80⁻ cell populations from the lungs of infected mice were most capable of stimulating mycoplasma-specific CD4⁺ Th cell responses in vitro. In vivo, these CD11c⁺F4/80⁻ cells were co-localized with CD4⁺ Th cells in inflammatory infiltrates in the lungs of mycoplasma-infected mice. Thus, CD11c⁺F4/80⁻ dendritic cells appear to be the major APC population responsible for pulmonary T cell stimulation in mycoplasma-infected mice, and these dendritic cells likely contribute to responses impacting disease pathogenesis.

[Mycoplasma pneumoniae capsular polysaccharides bind to DC-SIGN and promote the secretion of IL-10]

OBJECTIVE

To explore the interaction of Mycoplasma pneumoniae (M. pneumoniae) capsular polysaccharide (CPS) with dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) and its influence on the secretions of IL-10 and IL-12.

METHODS

M. pneumoniae CPS and lipid-associated membrane proteins (LAMPs) were extracted and purified, and the specific binding of CPS and DC-SIGN was detected using indirect immunofluorescence staining. The expressions of IL-10 and IL-12 was tested by ELISA in immature DC after treated by CPS or/and LAMPs.

RESULTS

Indirect immunofluorescence staining showed CPS could recognized and bind specifically to the DC, which could be blocked by the DC-SIGN-specific blocking antibody. ELISA revealed that the production of immunosuppressive cytokine IL-10 increased when immature DC were stimulated by CPS, and the effect was more obvious with the presence of LAMPs(P<0.05). But the production of IL-12 did not change significantly after stimulation of CPS or/and LAMPs.

CONCLUSION

The CPS of M.pneumoniae can recognize and bind to the DC-SIGN specifically and promote the immature DC to secret IL-10.

Syndrome de Miller Fisher avec anticorps anti GQ1b négatif au cours d’une pneumonie à Mycoplasma pneumoniae

Le Syndrome de Miller Fisher est caractérisé par l'association d'une ophtalmoplégie, d'une ataxie et d'une aréflexie ostéo-tendineuse. Une infection virale est le plus souvent retrouvée dans les jours ou semaines qui précèdent la symptomatologie. Nous rapportons un cas de syndrome de Miller Fisher survenu chez une femme de 75 ans, et ce au décours d'une infection pulmonaire à Mycoplasma pneumoniae. Les sérologies virales habituelles étaient négatives. Les anticorps anti GQ1b étaient absents. Il n'y avait pas de lésion du tronc cérébral à l'imagerie par résonnance magnétique. L’évolution clinique était favorable après perfusion d'immunoglobulines humaines polyvalentes et des macrolides en comprimés. La sérologie Mycoplasma pneumoniae doit être systématiquement recherchée dans le bilan du syndrome de Miller Fisher.

Airway epithelial NF-κB activation promotes Mycoplasma pneumoniae clearance in mice

BACKGROUND/OBJECTIVE

Respiratory infections including atypical bacteria Mycoplasma pneumoniae (Mp) contribute to the pathobiology of asthma and chronic obstructive pulmonary disease (COPD). Mp infection mainly targets airway epithelium and activates various signaling pathways such as nuclear factor κB (NF-κB). We have shown that short palate, lung, and nasal epithelium clone 1 (SPLUNC1) serves as a novel host defense protein and is up-regulated upon Mp infection through NF-κB activation in cultured human and mouse primary airway epithelial cells. However, the in vivo role of airway epithelial NF-κB activation in host defense against Mp infection has not been investigated. In the current study, we investigated the effects of in vivo airway epithelial NF-κB activation on lung Mp clearance and its association with airway epithelial SPLUNC1 expression.

METHODOLOGY/MAIN RESULTS

Non-antimicrobial tetracycline analog 9-t-butyl doxycycline (9-TB) was initially optimized in mouse primary tracheal epithelial cell culture, and then utilized to induce in vivo airway epithelial specific NF-κB activation in conditional NF-κB transgenic mice (CC10-(CA)IKKβ) with or without Mp infection. Lung Mp load and inflammation were evaluated, and airway epithelial SPLUNC1 protein was examined by immunohistochemistry. We found that 9-TB treatment in NF-κB transgene positive (Tg+), but not transgene negative (Tg-) mice significantly reduced lung Mp load. Moreover, 9-TB increased airway epithelial SPLUNC1 protein expression in NF-κB Tg+ mice.

CONCLUSION

By using the non-antimicrobial 9-TB, our study demonstrates that in vivo airway epithelial NF-κB activation promotes lung bacterial clearance, which is accompanied by increased epithelial SPLUNC1 expression.

[Levels of interleukin-4 and interferon-gamma in the bronchoalveolar lavage fluid of children with refractory Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To measure levels of interleukin-4 (IL-4) and interferon-gamma (INF-γ) in the bronchoalveolar lavage fluid (BALF) of children with refractory Mycoplasma pneumoniae pneumonia (RMPP), and to investigate changes in local Th1-Th2-type cytokine levels in children with RMPP and their significance.

METHODS

A total of 42 children with RMPP were divided into atopic (n=11) and non-atopic groups (n=31) according to whether they had eczema, allergic rhinitis, urticaria, and family history of allergic disease. The study also included a control group of 12 children with bronchial foreign bodies who underwent foreign body removal and were re-examined by fiberoptic bronchoscopy four weeks later. The different cells in BALF from all children were analyzed, and the levels of IL-4 and INF-γ in BALF were measured using enzyme-linked immunosorbent assay.

RESULTS

Compared with the control group, the total number of cells in BALF from children with RMPP increased significantly (P<0.05), the increase mainly accounted for by neutrophils (P<0.01), and levels of IL-4 and INF-γ in BALF from children with RMPP increased significantly (P<0.05). Compared with the control group, levels of IL-4 and INF-γ in BALF in the atopic group increased significantly (P<0.05). The level of INF-γ in BALF in the non-atopic group also increased significantly (P<0.05). There were no significant differences in INF-γ/IL-4 ratio among all groups (P>0.05).

CONCLUSIONS

Significant increase in cell numbers, especially neutrophils, as well as IL-4 and INF-γ levels, can be seen in BALF from children with RMPP, but there is no change to the INF-γ/IL-4 ratio. This indicates a significant local inflammatory response in children with RMPP, but there is no evidence of Th2-dominated inflammatory response.

Optimized serodiagnosis of Mycoplasma pneumoniae infections

Serologic methods are well established for the diagnosis of Mycoplasma pneumoniae infections in humans, but they are less sensitive than polymerase chain reaction (PCR). To improve their sensitivity, a new panel of antigens was tested. Compared with PCR results, up to 92% of PCR-positive patients were confirmed by our immunoblotting approach having a specificity between 92.6% and 100%.

Mast cell TNF receptors regulate responses to Mycoplasma pneumoniae in surfactant protein A (SP-A)-/- mice

BACKGROUND

Mycoplasma pneumoniae (Mp) frequently colonizes the airways of patients with chronic asthma and likely contributes to asthma exacerbations. We previously reported that mice lacking surfactant protein A (SP-A) have increased airway hyperresponsiveness (AHR) during M pneumoniae infection versus wild-type mice mediated by TNF-α. Mast cells (MCs) have been implicated in AHR in asthma models and produce and respond to TNF-α.

OBJECTIVE

Determine the contribution of MC/TNF interactions to AHR in airways lacking functional SP-A during Mp infection.

METHODS

Bronchoalveolar lavage fluid was collected from healthy and asthmatic subjects to examine TNF-α levels and M pneumoniae positivity. To determine how SP-A interactions with MCs regulate airway homeostasis, we generated mice lacking both SP-A and MCs (SP-A(-/-)Kit(W-sh/W-sh)) and infected them with M pneumoniae.

RESULTS

Our findings indicate that high TNF-α levels correlate with M pneumoniae positivity in human asthmatic patients and that human SP-A inhibits M pneumoniae-stimulated transcription and release of TNF-α by MCs, implicating a protective role for SP-A. MC numbers increase in M pneumoniae-infected lungs, and airway reactivity is dramatically attenuated when MCs are absent. Using SP-A(-/-)Kit(W-sh/W-sh) mice engrafted with TNF-α(-/-) or TNF receptor (TNF-R)(-/-) MCs, we found that TNF-α activation of MCs through the TNF-R, but not MC-derived TNF-α, leads to augmented AHR during M pneumoniae infection when SP-A is absent. Additionally, M pneumoniae-infected SP-A(-/-)Kit(W-sh/W-sh) mice engrafted with TNF-α(-/-) or TNF-R(-/-) MCs have decreased mucus production compared with that seen in mice engrafted with wild-type MCs, whereas burden was unaffected.

CONCLUSION

Our data highlight a previously unappreciated but vital role for MCs as secondary responders to TNF-α during the host response to pathogen infection.

[A family associated outbreak of Mycoplasma pneumoniae infection in a hospital ward]

OBJECTIVE

To describe the epidemiological and serological features on a family associated outbreak caused by Mycoplasma pneumoniae (MP) infection occurred in Beijing in August 2007.

METHODS

Mutual exposure of the family members was investigated and retrospective medical record was reviewed for the hospitalized patients. Serum antibodies to MP were measured and chest X-rays were taken for all the family members.

RESULTS

This family consisted of 5 members, with fixed members as the boy (13 years old), his father (43 years old) and mother (44 years old), grandmother (64 years old) and uncle (32 years old) who was involved in taking care of the sick boy and his father. During 23 days of the event, four of all the five family members were ill. Three (boy, father and uncle) had radiographic pneumonia, whose paired sera all showed a ≥ fourfold increase in antibody titer, and two of them were confirmed by chest X-ray on day 2 after onset of fever. The grandmother suffered from bronchitis, with positive (PA) serum antibody to MP. Serum MP-IgG from the father and uncle was positive, 3 days and 2 days after the onset of fever. The chances of contact between grandmother with the boy and uncle with the father were both only in the hospital wards. Only the mother remained asymptomatic, with her serum MP-IgM(-) and MP-IgG(+) for which the blood sample was collected 37 days after close contact with the boy. The longest time of exposure to the patients was between mother and the boy but only the mother did not increase her total workload or feeling for fatigue.

RESULTS

of MP-IgG from post-infection did not completely defend against the repeated MP infection. Combined risk factors as index patients with severe cough, prolonged close contact, poorly ventilation of the environment, and family members with excessive fatigue might work as the causes of this family MP outbreak.

[Levels of TNF-α, IL-6 and IL-10 in bronchoalveolar lavage fluid in children with Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To study the levels and roles of cytokines TNF-α, IL-6 and IL-10 in bronchoalveolar lavage fluid (BALF) in children with Mycoplasma pneumoniae pneumonia (MPP).

METHODS

The levels of TNF-α, IL-6 and IL-10 in BALF were measured using ELISA in children with MPP at acute stage (n=45) and at remission stage (n=30). Twenty children without lung lesions severed as the control group.

RESULTS

The TNF-α, IL-6 and IL-10 levels in BALF were higher in children with MPP at acute stage than those in the control group (P<0.05). The levels of TNF-α and IL-6 in BALF at remission stage were reduced to the levels similar to the control group and were significantly lower than those at the acute stage in children with MPP. However, the levels of IL-10 in BALF remained at higher levels at remission stage in children with MPP.

CONCLUSIONS

The levels of TNF-α, IL-6 and IL-10 in BALF increase in children with MPP at acute stage, suggesting that the cytokines may be involved in the pathogenesis of MPP.

SPLUNC1 promotes lung innate defense against Mycoplasma pneumoniae infection in mice

Short palate, lung, and nasal epithelium clone 1 (SPLUNC1) protein is highly expressed in normal airways, but is dramatically decreased in allergic and cigarette smoke exposure settings. We have previously demonstrated SPLUNC1 in vitro antibacterial property against Mycoplasma pneumoniae (Mp). However, its in vivo biological functions remain unclear. The objectives of this study were to determine the in vivo functions of SPLUNC1 following bacterial (eg, Mp) infection, and to examine the underlying mechanisms. We generated SPLUNC1-deficient mice and utilized transgenic mice overexpressing human SPLUNC1 exclusively within the airway epithelium. These mice were infected with Mp and, twenty-four hours post infection, their host defense responses were compared to littermate controls. Mp levels and inflammatory cells increased in the lungs of SPLUNC1(-/-) mice as compared to wild type controls. SPLUNC1 deficiency was shown to contribute to impaired neutrophil activation. In contrast, mice overexpressing hSPLUNC1 exclusively in airway epithelial cells demonstrated lower Mp levels. Furthermore, neutrophil elastase activity was significantly increased in mice overexpressing hSPLUNC1. Lastly, we demonstrated that SPLUNC1 enhanced Mp-induced human neutrophil elastase (HNE) activity, and HNE directly inhibited the growth of Mp. Our findings demonstrate a critical in vivo role of SPLUNC1 in host defense against bacterial infection, and likely provide a novel therapeutic approach to restore impaired lung innate immune responses to bacteria in patients with chronic lung diseases.

PAComplex: a web server to infer peptide antigen families and binding models from TCR-pMHC complexes

One of the most adaptive immune responses is triggered by specific T-cell receptors (TCR) binding to peptide-major histocompatibility complexes (pMHC). Despite the availability of many prediction servers to identify peptides binding to MHC, these servers are often lacking in peptide-TCR interactions and detailed atomic interacting models. PAComplex is the first web server investigating both pMHC and peptide-TCR interfaces to infer peptide antigens and homologous peptide antigens of a query. This server first identifies significantly similar TCR-pMHC templates (joint Z-value ≥ 4.0) of the query by using antibody-antigen and protein-protein interacting scoring matrices for peptide-TCR and pMHC interfaces, respectively. PAComplex then identifies the homologous peptide antigens of these hit templates from complete pathogen genome databases (≥10(8) peptide candidates from 864,628 protein sequences of 389 pathogens) and experimental peptide databases (80,057 peptides in 2287 species). Finally, the server outputs peptide antigens and homologous peptide antigens of the query and displays detailed interacting models (e.g. hydrogen bonds and steric interactions in two interfaces) of hitTCR-pMHC templates. Experimental results demonstrate that the proposed server can achieve high prediction accuracy and offer potential peptide antigens across pathogens. We believe that the server is able to provide valuable insights for the peptide vaccine and MHC restriction. The PAComplex sever is available at http://PAcomplex.life.nctu.edu.tw.

Preceding infections and anti-ganglioside antibody profiles assessed by a dot immunoassay in 306 French Guillain-Barré syndrome patients

We describe by an in-house dot immunoassay, specific anti-ganglioside and sulfatide antibodies, by comparing the results from a large group of 134 infected French GBS patients and those from 172 noninfected French GBS and 142 control groups. A recent infection was identified in 134/306 (43.8%) GBS patients: Campylobacter jejuni (24.6%) was the most common agent, followed by cytomegalovirus (12.4%), Mycoplasma pneumoniae (3.2%) and Epstein-Barr virus (1.3%). Anti-ganglioside antibodies were detected in 97/306 (31.7%) of total GBS patients, 82/134 (61.2%) of GBS patients with a recent identified infection and 15/172 (8.7%) of the patients without identified infection. According to the specificities and antibody classes, four specific IgG antibody profiles were individualised against the two major GM1 and GD1a gangliosides in motor axonal C. jejuni-associated GBS variants, against GQ1b and disialylated gangliosides in Miller Fisher syndrome and its variants. One specific IgM profile against GM2 was found in 16/38 (42%) of severe sensory demyelinating CMV-associated GBS and in 8/17 (47%) of subjects with recent CMV infection with no neurological disease. IgG or IgM antibodies to GM1 were found in 5/10 M. pneumoniae-infected patients. IgM antibodies to GM1 were observed in the control groups, 15% of the 74 patients with amyotrophic lateral sclerosis, 19% of the 51 patients with chronic inflammatory demyelinating polyneuropathy, and 9% of the 21 healthy control subjects. The fine specificity of the four IgG antibody profiles and the IgM anti-GM2 profile is closely related to the nature of the preceding infections and the pattern of clinical features.

[The analyses of Mycoplasma pneumoniae antibody test results in patients with respiratory tract infection]

OBJECTIVE

To investigate the relationship between the infection rate of Mycoplasma pneumoniae (MP) and age, sex and season.

METHODS

Passive agglutination assay was used to detect Mycoplasma pneumoniae antibodies (MP-Ab) in the serum of patients with respiratory tract infection, and MP-Ab test results in 2010 were analyzed.

RESULTS

The positive rates of 5 year test results were 30.10%; among the results, the positive rates of male and female patients were respectively 30.74% and 36.12%, the difference was statistically significant (P < 0.05); And every age group were significantly different (P < 0.001), among each group, the positive rate of 3-14 years old patients was the highest; the season was no significant difference in incidence rates; the patients of positive titer > 1:640 accounted for 10.18% of the patients.

CONCLUSION

MP infection is increasing year by year, children aged 3 to 14 has become the high-risk groups. Women are more susceptible to MP than the men and the chances of infection are throughout the year, but the most of the patients have a good prognosis.

[Serologic diagnosis of Mycoplasma pneumoniae infections]

Mycoplasma pneumoniae is a human pathogen with worldwide distribution. This microorganism is a common cause (10-30%) of community-acquired pneumonia, also called primary atypical pneumonia because of the spectrum of clinical and radiological findings. The immune response is mainly based on rapid antibody production against peptide and glycolipid antigens derived from this microorganism. During the primary infection, IgM levels generally rise within the first week, and are then followed by an IgG response. Titers of IgG and IgA increase in reinfections. Microbiological diagnosis is based on specific antibody detection. Polymerase chain reaction (PCR) techniques performed on sputum or pharyngeal/nasopharyngeal exudates, as well as the development of multiplex PCR reactions allowing identification of M. pneumoniae and other respiratory pathogens, would by highly useful in routine diagnosis. The most common serological techniques are complement fixation, immunofluorescence, particle agglutination, and enzyme immunoassay. Diagnosis should be performed by selecting the most appropriate test according to functional criteria and population groups. Specific detection of IgM antibodies should not be included in the differential diagnosis in adults and young people. Diagnostic criteria including seroconversion or rising IgG titers may not be clinically useful, because of the time delay and the difficulty of obtaining a second serum specimen for testing, given the mildness of the clinical symptoms.

[Th1/Th2 immune response in bronchoalveolar lavage fluid in children with severe Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To study the status of Th1/Th2 immune response and the value of the detection of cytokines in bronchoalveolar lavage fluids (BALF) by examining the levels of IFN-γ and IL-4 in BALF and serum in children with severe Mycoplasma pneumonia (MPP).

METHODS

The levels of IFN-γ and IL-4 in BALF and serum were measured using ELISA in 25 children with severe MPP, 25 children with mild MPP and 25 children with foreign body in bronchus.

RESULTS

The levels of IL-4 and IFN-γ and the IL-4/IFN-γ ratio in BALF in children with severe MPP were significantly higher than those in children with foreign body in bronchus (P<0.01 or P<0.05). The serum levels of IL-4 and the IL-4/IFN-γ ratio in children with severe MPP were significantly higher than those in children with foreign body in bronchus (P<0.01) or with mild MPP (P<0.05). The levels of IL-4 and the IL-4/IFN-γ ratio in BALF were significantly higher than in serum (P<0.05).

CONCLUSIONS

The data suggest that the imbalance of Th1/Th2 exists in children with severe MPP and it seems to represent a predominant Th2-like cytokine response. The detection of cytokines in BALF appears to be more sensitive than in serum and may be of value in the diagnosis and therapy of MPP.

[Serum levels of IL-13 and TNF-alpha in children with Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To examine serum levels of interleukin-13 (IL-13) and tumor necrosis factor alpha (TNF-alpha) in children with Mycoplasma pneumoniae (MP) pneumonia.

METHODS

Eighty children with MP pneumonia complicated by wheezing or without (n=40 each), 40 children with pneumonia from non-MP infection and 40 healthy children were enrolled. Serum levels of IL-13 and TNF-alpha were measured using ELISA.

RESULTS

The serum levels of IL-13 and TNF-alpha in the MP pneumonia group were significantly higher than those in non-MP pneumonia group and the healthy control group (P<0.01). The children with MP pneumonia complicated by wheezing had increased serum levels of IL-13 (214.6 + or - 67.2 ng/L vs 189.6 + or - 52.1 ng/L; P<0.01) and TNF-alpha(0.55 + or - 0.13 ng/mL vs 0.42 + or - 0.16 ng/mL; P<0.01)compared with those without wheezing.

CONCLUSIONS

The increase in serum levels of IL-13 and TNF-alpha may play important roles in the pathogenesis of MP pneumonia and wheezing attack in children.