Design of a novel multiepitope vaccine with CTLA-4 extracellular domain against Mycoplasma pneumoniae: A vaccine-immunoinformatics approach

BACKGROUND

Community-acquired pneumonia often stems from the macrolide-resistant strain of Mycoplasma pneumoniae, yet no effective vaccine exists against it.

METHODS

This study proposes a vaccine-immunoinformatics strategy for Mycoplasma pneumoniae and other pathogenic microbes. Specifically, dominant B and T cell epitopes of the Mycoplasma pneumoniae P30 adhesion protein were identified through immunoinformatics method. The vaccine sequence was then constructed by coupling with CTLA-4 extracellular region, a novel molecular adjuvant for antigen-presenting cells. Subsequently, the vaccine's physicochemical properties, antigenicity, and allergenicity were verified. Molecular dynamics modeling was employed to confirm interaction with TLR-2, TLR-4, B7-1, and B7-2. Finally, the vaccine underwent in silico cloning for expression.

RESULTS

The vaccine exhibited both antigenicity and non-allergenicity. Molecular dynamics simulation, post-docking with TLR-2, TLR-4, B7-1, and B7-2, demonstrated stable interaction between the vaccine and these molecules. In silico cloning confirmed effective expression of the vaccine gene in insect baculovirus vectors.

CONCLUSION

This vaccine-immunoinformatics approach holds promise for the development of vaccines against Mycoplasma pneumoniae and other pathogenic non-viral and non-bacterial microbes.

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.