Irreversible airway obstruction in asthma

Aging-Related Mechanisms Contribute to Corticosteroid Insensitivity in Elderly Asthma

Asthma in elderly populations is an increasing health problem that is accompanied by diminished lung function and frequent exacerbations. As potent anti-inflammatory drugs, corticosteroids are commonly used to reduce lung inflammation, improve lung function, and manage disease symptoms in asthma. Although effective for most individuals, older patients are more insensitive to corticosteroids, making it difficult to manage asthma in this population. With the number of individuals older than 65 continuing to increase, it is important to understand the distinct mechanisms that promote corticosteroid insensitivity in the aging lung. In this review, we discuss corticosteroid insensitivity in asthma with an emphasis on mechanisms that contribute to persistent inflammation and diminished lung function in older individuals.

The impact of multistrains of probiotics on Th17-related cytokines in patients with asthma: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

Asthma is known as one of the most common chronic inflammatory diseases characterized by recurrent obstruction and inflammation of the airways. Probiotics are defined as a group of beneficial living microorganisms that are beneficial in many disorders, including allergies. The aim of this study was to investigate the probiotic supplement effects on improvement of clinical asthma symptom and changes in the pattern of Th17-related inflammatory cytokines in asthmatic patients.

METHODS

This was a randomized controlled clinical trial with parallel, double-blind groups. Forty patients with asthma were enrolled and received 1 capsule/day of a probiotic supplement for 8 weeks. Respiratory function tests; and the level of IL-6, IL-17, IL-21 and TGF-β were evaluated at the baseline and end of intervention.

RESULTS

The results showed that the level of IL-6 and IL-17 in patients after receiving probiotics was reduced and expression of TGF-β was increased as compared to the baseline. Also, the expression of IL-17 and IL-21 in the probiotic group was significantly lower than the placebo group at the end of the intervention. In addition, an improvement in pulmonary function tests and clinical symptoms was observed after receiving probiotics.

CONCLUSIONS

Eight-weeks treatment with a probiotic supplementation suggests that it may effect on Th17 cells-associated IL-6, IL-17 and TGF-β; and Forced Expiratory Volume in 1 s and Forced Vital Capacity. Taken together, these results suggest that probiotics may have the ability to affect neutrophilic asthma and they can possibly be used besides common treatments for patients with neutrophilic asthma.

Early Features of Chronic Obstructive Pulmonary Disease in Patients with Asthma: Is there ACO before ACO?

The diagnosis of asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) is considered when a patient presents features of both asthma and COPD, usually including a component of irreversible airway obstruction (IRAO). However, some patients with asthma, particularly smokers, may have various features typical of COPD in the absence of such component of IRAO. Features of early COPD can be found at a young age in such patients even with normal spirometry. More longitudinal studies should be conducted to determine steps needed to improve clinical outcomes of these patients including the early recognition of these changes and the application of preventative/therapeutic interventions.

Quantitative CT metrics are associated with longitudinal lung function decline and future asthma exacerbations: Results from SARP-3

BACKGROUND

Currently, there is limited knowledge regarding which imaging assessments of asthma are associated with accelerated longitudinal decline in lung function.

OBJECTIVES

We aimed to assess whether quantitative computed tomography (qCT) metrics are associated with longitudinal decline in lung function and morbidity in asthma.

METHODS

We analyzed 205 qCT scans of adult patients with asthma and calculated baseline markers of airway remodeling, lung density, and pointwise regional change in lung volume (Jacobian measures) for each participant. Using multivariable regression models, we then assessed the association of qCT measurements with the outcomes of future change in lung function, future exacerbation rate, and changes in validated measurements of morbidity.

RESULTS

Greater baseline wall area percent (β = -0.15 [95% CI = -0.26 to -0.05]; P < .01), hyperinflation percent (β = -0.25 [95% CI = -0.41 to -0.09]; P < .01), and Jacobian gradient measurements (cranial-caudal β = 10.64 [95% CI = 3.79-17.49]; P < .01; posterior-anterior β = -9.14, [95% CI = -15.49 to -2.78]; P < .01) were associated with more severe future lung function decline. Additionally, greater wall area percent (rate ratio = 1.06 [95% CI = 1.01-1.10]; P = .02) and air trapping percent (rate ratio =1.01 [95% CI = 1.00-1.02]; P = .03), as well as lower decline in the Jacobian determinant mean (rate ratio = 0.58 [95% CI = 0.41-0.82]; P < .01) and Jacobian determinant standard deviation (rate ratio = 0.52 [95% CI = 0.32-0.85]; P = .01), were associated with a greater rate of future exacerbations. However, imaging metrics were not associated with clinically meaningful changes in scores on validated asthma morbidity questionnaires.

CONCLUSIONS

Baseline qCT measures of more severe airway remodeling, more small airway disease and hyperinflation, and less pointwise regional change in lung volumes were associated with future lung function decline and asthma exacerbations.

Asthma with Irreversible Airway Obstruction in Smokers and Nonsmokers: Links between Airway Inflammation and Structural Changes

BACKGROUND

The development of irreversible airway obstruction (IRAO) in asthma is related to lung/airway inflammatory and structural changes whose characteristics are likely influenced by exposure to tobacco smoke.

OBJECTIVE

To investigate the interplay between airway and lung structural changes, airway inflammation, and smoking exposure in asthmatics with IRAO.

METHODS

We studied asthmatics with IRAO who were further classified according to their smoking history, those with ≥20 pack-years of tobacco exposure (asthmatics with smoking-related IRAO [AwS-IRAO]) and those with <5 pack-years of tobacco exposure (asthmatics with nonsmoking-related IRAO [AwNS-IRAO]). In addition to recording baseline clinical and lung function features, all patients had a chest computed tomography (CT) from which airway wall thickness was measured and quantitative and qualitative assessment of emphysema was performed. The airway inflammatory profile was documented from differential inflammatory cell counts on induced sputum.

RESULTS

Ninety patients were recruited (57 AwS-IRAO and 33 AwNS-IRAO). There were no statistically significant differences in the extent of emphysema and gas trapping between groups on quantitative chest CT analysis, although Pi10, a marker of airway wall thickness, was significantly higher in AwS-IRAO (p = 0.0242). Visual analysis showed a higher prevalence of emphysema (p = 0.0001) and higher emphysema score (p < 0.0001) in AwS-IRAO compared to AwNS-IRAO and distribution of emphysema was different between groups. Correlations between radiological features and lung function were stronger in AwS-IRAO. In a subgroup analysis, we found a correlation between airway neutrophilia and emphysematous features in AwS-IRAO and between eosinophilia and both airway wall thickness and emphysematous changes in AwNS-IRAO.

CONCLUSIONS

Although bronchial structural changes were relatively similar in smoking and nonsmoking patients with asthma and IRAO, emphysematous changes were more predominant in smokers. However, neutrophils in AwS-IRAO and eosinophils in AwNS-IRAO were associated with lung and airway structural changes.

Regulatory B cells control airway hyperreactivity and lung remodeling in a murine asthma model

BACKGROUND

Asthma is a widespread, multifactorial chronic airway disease. The influence of regulatory B cells on airway hyperreactivity (AHR) and remodeling in asthma is poorly understood.

OBJECTIVE

Our aim was to analyze the role of B cells in a house dust mite (HDM)-based murine asthma model.

METHODS

The influence of B cells on lung function, tissue remodeling, and the immune response were analyzed by using wild-type and B-cell-deficient (μMT) mice and transfer of IL-10-proficient and IL-10-deficient B cells to μMT mice.

RESULTS

After HDM-sensitization, both wild-type and μMT mice developed AHR, but the AHR was significantly stronger in μMT mice, as confirmed by 2 independent techniques: invasive lung function measurement in vivo and examination of precision-cut lung slices ex vivo. Moreover, airway remodeling was significantly increased in allergic μMT mice, as shown by enhanced collagen deposition in the airways, whereas the numbers of FoxP3⁺ and FoxP3^- IL-10-secreting regulatory T cells were reduced. Adoptive transfer of IL-10-proficient but not IL-10-deficient B cells into μMT mice before HDM-sensitization attenuated AHR and lung remodeling. In contrast, FoxP3⁺ regulatory T cells were equally upregulated by transfer of IL-10-proficient and IL-10-deficient B cells.

CONCLUSION

Our data in a murine asthma model illustrate a central role of regulatory B cells in the control of lung function and airway remodeling and may support future concepts for B-cell-targeted prevention and treatment strategies for allergic asthma.

Correlations of forced oscillometric bronchodilator response with airway inflammation and disease duration in asthma

INTRODUCTION

Airway resistance and reactance, measured by forced oscillometry, are used to measure the airway obstruction in patients with asthma.

OBJECTIVES

This study aimed to investigate the oscillometric bronchodilator responses in treated and untreated asthma and evaluate its association with airway inflammation and disease duration.

MATERIALS AND METHODS

This study included 30 nonsmoking patients with mild to moderate treated asthma, 25 patients with newly diagnosed untreated asthma and 29 control subjects. Spirometric and oscillometric measurements were performed before and after inhalation of 400 µg salbutamol. Disease duration was defined as the number of years since asthma diagnosis.

RESULTS

At airway resistance of 5 Hz (R5) and 20 Hz (R20), bronchodilator responses in patients with untreated and treated asthma were greater than those in control subjects. In patients with untreated asthma, higher fractional exhaled nitric oxide concentration (FeNO) levels were strongly correlated with greater reversibility of R20 (r_s  = -0.621, P < 0.001). In patients with treated asthma, there was no significant association between FeNO and oscillometric reversibility, whereas longer disease duration was significantly associated with lesser bronchodilator response at R20 (r_s  = 0.441, P < 0.05). Treated asthma patients with longer disease duration (≥10 years) showed significantly higher post-bronchodilator R5 and R20 than the treated asthma patients with shorter disease duration (<10 years).

CONCLUSION

The present study provides further evidence of an association between airway inflammation and variable airway obstruction in asthma patients and indicates that long-term disease duration could be related to poorly reversible airway resistance in patients with mild to moderate asthma.

Prevalence and factors associated with asthma among adolescents and adults in Uganda: a general population based survey

Background

Recent large-scale population data on the prevalence of asthma and its risk factors are lacking in Uganda. This survey was conducted to address this data gap.

Methods

A general population based survey was conducted among people ≥12 years. A questionnaire was used to collect participants socio-demographics, respiratory symptoms, medical history, and known asthma risk factors. Participants who reported wheeze in the past 12 months, a physician diagnosis of asthma or current use of asthma medications were classified as having asthma. Asthmatics who were ≥ 35 years underwent spirometry to determine how many had fixed airflow obstruction (i.e. post bronchodilator forced expiratory volume in one second/forced vital capacity (FEV₁/FVC) ratio < lower limit of normal (LLN). Descriptive statistics were used to summarize participants’ characteristics. Prevalence of asthma was calculated as a proportion of asthmatics over total survey population. To obtain factors independently associated with asthma, a random-effects model was fitted to the data.

Results

Of the 3416 participants surveyed, 61.2% (2088) were female, median age was 30 years (IQR, 20–45) and 323 were found to have asthma. Sixteen people with asthma ≥35 years had fixed airflow obstruction. The prevalence of asthma was 11.0% (95% CI:8.9–13.2; males 10.3%, females 11.4%, urban 13.0% and rural 8.9%. Significantly more people with asthma smoked than non-asthmatics: 14.2% vs. 6.3%, p < 0.001, were exposed to biomass smoke: 28.0% vs. 20.0%, p < 0.001, had family history of asthma: 26.9% vs. 9.4%, p, < 0.001, had history of TB: 3.1% vs. 1.30%, p = 0.01, and had hypertension: 17.9% vs. 12.0%, p = 0. 003. In multivariate analysis smoking, (adjusted odds ratio (AOR), 3.26 (1.96–5.41, p < 0.001) family history of asthma, AOR 2.90 (98–4.22 p- < 0.001), nasal congestion, AOR 3.56 (2.51–5.06, p < 0.001), biomass smoke exposure, AOR 2.04 (1.29–3.21, p = 0.002) and urban residence, AOR 2.01(1.23–3.27, p = 0.005) were independently associated with asthma.

Conclusion

Asthma is common in Uganda and is associated with smoking, biomass smoke exposure, urbanization, and allergic diseases. Health care systems should be strengthened to provide asthma care. Measures to reduce exposure to the identified associated factors are needed.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-6562-2) contains supplementary material, which is available to authorized users.

Bronchodilator responsiveness as a predictor of success for bronchial thermoplasty

BACKGROUND AND OBJECTIVE

A characteristic feature of asthma is hypertrophied airway smooth muscle, responsible for bronchoconstriction. This is the target of bronchial thermoplasty (BT). It is known that with increasing time and severity some patients develop remodelled airways with fixed airflow obstruction. The question arises whether these patients will still respond to BT.

METHODS

Forty-nine consecutive severe asthmatic patients were prospectively evaluated at baseline and then 6 months after BT. The characteristics recorded included medication usage, exacerbation history, spirometry and the Asthma Control Questionnaire 5-Item Version score (ACQ-5). Seven patients were excluded as they did not demonstrate airflow obstruction at baseline (forced expiratory ratio (forced expiratory volume in 1 s (FEV₁ )/forced vital capacity (FVC)) < 70%). The remaining 42 patients were divided into two cohorts based on their response to bronchodilator. Eighteen patients in whom the FEV₁ improved by at least 12% and 200 mL following bronchodilator were allocated to Group 1 (reversible). The remaining patients were allocated to Group 2 (fixed). The outcomes following BT in these two groups were then compared.

RESULTS

The patient age was 57.2 ± 12.4 years, the ACQ-5 was 3.2 ± 1.0 and the FEV₁ 56.0 ± 16.4% predicted. At baseline, the patient cohorts were very similar, save for the response to bronchodilator, which was 28.1 ± 12.5% in Group 1 and 4.1 ± 5.3% in Group 2. Both groups responded to BT equally well, with significant improvements in ACQ-5, salbutamol usage, exacerbation frequency and the weaning of oral corticosteroids.

CONCLUSION

In patients with severe asthma, the presence or absence of variable airflow obstruction as measured by spirometry does not appear to influence outcomes from BT.

Mepolizumab for Treating Severe Eosinophilic Asthma: An Evidence Review Group Perspective of a NICE Single Technology Appraisal

As part of its single technology appraisal (STA) process, the National Institute for Health and Care Excellence (NICE) invited the company (GlaxoSmithKline) that manufactures mepolizumab (Nucala^®) to submit evidence on the clinical and cost effectiveness of mepolizumab for the treatment of severe eosinophilic asthma. The School of Health and Related Research Technology Appraisal Group (ScHARR-TAG) at the University of Sheffield was commissioned to act as the independent evidence review group (ERG). The ERG produced a review of the evidence for the clinical and cost effectiveness of mepolizumab as add-on to standard of care (SoC) compared with SoC and omalizumab, based upon the company's submission to NICE. The clinical-effectiveness evidence in the company's submission was based predominantly on three randomised controlled trials (DREAM, MENSA and SIRIUS) comparing add-on mepolizumab with placebo plus SoC. The relevant population was defined in terms of degree of asthma severity (four or more exacerbations in the previous year and/or dependency on maintenance oral corticosteroids [mOCS]) and degree of eosinophilia (a blood eosinophil count of ≥ 300 cells/µl in the previous year) based on post hoc subgroup analyses of the pivotal trials. Other subpopulations were considered throughout the appraisal, defined by different eosinophil measurements, number of exacerbations and dependency (or lack thereof) on mOCS. Statistically significant reductions in clinically significant exacerbations were observed in patients receiving mepolizumab compared with SoC meta-analysed across MENSA and DREAM in the modified intention-to-treat (ITT) population (rate ratio [RR] 0.51; 95% confidence interval [CI] 0.42-0.62) as well as in the relevant population (RR 0.47; 95% CI 0.36-0.62). In terms of quality of life, differences on the St. George's Respiratory Questionnaire in MENSA for add-on subcutaneous mepolizumab 100 mg vs. placebo were 7 and 7.5 units in the modified ITT and relevant populations, respectively. A number of issues in the clinical evidence base warrant caution in its interpretation. The ERG noted that the definition of SoC used in the trials differed from that in clinical practice, where patients with severe uncontrolled asthma start treatment with a mOCS. The company's economic post-consultation analysis incorporating a confidential patient access scheme (PAS) estimated that the incremental cost-effectiveness ratio (ICER) for add-on mepolizumab compared with SoC was £27,418 per quality-adjusted life-year (QALY) gained in the relevant population if patients stopped mepolizumab after 1 year unless (1) the number of exacerbations decreased at least 50% or (2) a reduction in corticosteroids dose was achieved whilst maintaining asthma control. The ERG applied an age adjustment to all utilities and corrected the post-continuation assessment utilities, which resulted in an ICER for add-on mepolizumab compared with SoC of £29,163 per QALY gained. The ERG noted that this ICER was not robust for patients who continued treatment due to a corticosteroid dose reduction where exacerbations had decreased by less than 50%, because corticosteroid dose reduction was not allowed in the main trial in which the evidence was gathered (MENSA). The NICE appraisal committee (AC) concluded that add-on mepolizumab could be recommended as an option for treating severe refractory eosinophilic asthma in adults for the relevant population when the stopping rule suggested by the company was applied. The AC also concluded that the comparison between mepolizumab and omalizumab was not clinically relevant or methodologically robust.

Comparative prevalence of co-morbidities in smoking and non-smoking asthma patients with incomplete reversibility of airway obstruction, non-smoking asthma patients with complete reversibility of airway obstruction and COPD patients

BACKGROUND

Asthma with incomplete reversibility of airway obstruction (IRAO) may often be associated to smoking-induced changes. Nevertheless, a high proportion of patients showing IRAO have never smoked. These patients with IRAO often share features of patients with chronic obstructive pulmonary disease (COPD). Although IRAO is still a poorly defined condition, it has been associated with a higher morbidity and mortality than asthma with complete reversibility of airway obstruction (CRAO) or even COPD alone. A high prevalence of comorbidities could contribute to the reported poorer clinical outcome in IRAO, in comparison to CRAO or COPD alone.

AIM

To determine the prevalence of past and current comorbidities in IRAO patients compared to patients with CRAO or COPD.

METHODS

This was a retrospective, cross-sectional study. Demographic data, clinical characteristics and 36 predetermined comorbidities documented from self-report and chart review, were recorded from smoking-associated IRAO (S-IRAO), non-smoking IRAO (NS-IRAO), CRAO and COPD patients.

RESULTS

A total of 199 patients were included in the final analysis (111F/88M, mean (±SD) age of 63 ± 10 years). The CRAO group had more comorbidities than the three other groups, but this difference was significant only with the NS-IRAO group (P = 0.04). For most comorbidities, the prevalence of comorbidities in both IRAO sub-groups was intermediate between CRAO and COPD, with significant differences between S-IRAO and NS-IRAO only for hypertension (P = 0.03), nasal polyps (P = 0.002) and pneumonia (P = 0.04). Typical asthma-associated comorbidities tended to be more prevalent in NS-IRAO patients and COPD-associated comorbidities in S-IRAO patients.

CONCLUSION

In this study, the prevalence of comorbidities was not superior in patients with IRAO, compared to those with CRAO or COPD alone. The prevalence of comorbidities in the two main types of IRAO patients reflects exposure to cigarette smoke and asthma-related mechanisms.

Factors associated with generic health-related quality of life in adult asthma patients in Germany: Cross-sectional study

OBJECTIVES

Given a 9% lifetime prevalence of asthma in Germany and the impairment of health-related quality of life (HRQOL) that goes along with it, it is important to understand parameters affecting HRQOL in asthma patients. Objective of this study was therefore to determine factors associated with generic HRQOL in asthma patients.

METHODS

Data for cross-sectional analyses were obtained from the baseline of an ongoing cohort study.

INCLUSION CRITERIA

physician-diagnosed asthma; age ≥18 years; disease duration ≥3 months; no acute psychiatric/neurological disease; sufficient knowledge of German. HRQOL was assessed by the Short Form 12 Health Survey Questionnaire (SF-12), which comprises a physical (PCS-12) and a mental component (MCS-12). Information on a broad range of parameters potentially influencing HRQOL was collected by examining the patients' medical records and via a self-administered questionnaire. Those parameters were of socio-demographic, disease-specific, treatment-related or psychosocial nature. We conducted multivariable linear regression analyses to assess determinants of HRQOL.

RESULTS

In total, 196 asthma patients participated in the study (mean age: 48 years (range: 18-90); 60.2% females). In multivariable analysis, PCS-12 was negatively associated with older age, being female, insufficient disease control, higher number of medications in tablet form and reporting symptoms of depression. MCS-12 was negatively associated with being female, living alone, insufficient disease control, and reporting symptoms of anxiety or depression.

CONCLUSIONS

Focusing on disease control and screening for depression and anxiety may be promising approaches to improve HRQOL in adult asthma patients. If a patient shows alarming symptoms of anxiety and/or depression, the patient should then be referred for psychiatric treatment.

The Coagulant Factor Xa Induces Protease-Activated Receptor-1 and Annexin A2-Dependent Airway Smooth Muscle Cytokine Production and Cell Proliferation

During asthma exacerbation, plasma circulating coagulant factor X (FX) enters the inflamed airways and is activated (FXa). FXa may have an important role in asthma, being involved in thrombin activation and an agonist of protease-activated receptor-1 (PAR-1). Extracellular annexin A2 and integrins are also implicated in PAR-1 signaling. In this study, the potential role of PAR-1 in mediating the effects of FXa on human airway smooth muscle (ASM) cell cytokine production and proliferation was investigated. FXa (5-50 nM), but not FX, stimulated increases in ASM IL-6 production and cell number after 24- and 48-hour incubation, respectively (P < 0.05; n = 5). FXa (15 nM) also stimulated increases in the levels of mRNA for cytokines (IL-6), cell cycle-related protein (cyclin D1), and proremodeling proteins (FGF-2, PDGF-B, CTGF, SM22, and PAI-1) after 3-hour incubation (P < 0.05; n = 4). The actions of FXa were insensitive to inhibition by hirudin (1 U/ml), a selective thrombin inhibitor, but were attenuated by SCH79797 (100 nM), a PAR-1 antagonist, or Cpd 22 (1 μM), an inhibitor of integrin-linked kinase. The selective targeting of PAR-1, annexin A2, or β1-integrin by small interfering RNA and/or by functional blocking antibodies also attenuated FXa-evoked responses. In contrast, the targeting of annexin A2 did not inhibit thrombin-stimulated ASM function. In airway biopsies of patients with asthma, FXa and annexin A2 were detected in the ASM bundle by immunohistochemistry. These findings establish FXa as a potentially important asthma mediator, stimulating ASM function through actions requiring PAR-1 and annexin A2 and involving integrin coactivation.

Assessment of Consistency of Fixed Airflow Obstruction Status during Budesonide/Formoterol Treatment and Its Effects on Treatment Outcomes in Patients with Asthma

BACKGROUND

The consistency of fixed airflow limitation status during treatment in patients with asthma is unknown.

OBJECTIVE

The objective of this study was to determine the consistency of fixed airflow obstruction (FAO) status during treatment and effects on treatment response.

METHODS

This post hoc analysis from a 12-week study (NCT00652002) assessed patients aged 12 years or more with moderate-to-severe asthma randomized to twice-daily budesonide/formoterol (BUD/FM) via pressurized metered-dose inhaler (pMDI) 320/9 μg, BUD pMDI 320 μg, FM 9 μg via dry-powder inhaler, or placebo. FAO status was assessed postbronchodilator at screening and after study drug administration at weeks 2, 6, and 12 via the forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) ratio < lower limit of normal (LLN) (FAO+) or ≥ LLN (FAO-). Patients with persistent FAO- and FAO+ retained their screening FAO status at all visits. Patients with inconsistent FAO changed categories at least once during the study. Assessments included early withdrawal due to predefined worsening asthma events (PAEs), lung function, and symptoms.

RESULTS

Of 386 patients, 29% had persistent FAO+, 31% inconsistent FAO, and 40% persistent FAO-. PAEs were lowest in the FAO- group overall and with BUD/FM treatment in patients with FAO+ and inconsistent FAO. Baseline demographics and treatment responses of the inconsistent FAO group were most similar to the FAO+ group. The greatest improvements in asthma control days and use of rescue medications were seen with BUD/FM treatment, regardless of FAO status.

CONCLUSIONS

Approximately one third of patients with moderate-to-severe asthma in this study had inconsistent FAO, and their treatment responses were most similar to patients with FAO+. Regardless of FAO status, patients treated with BUD/FM experienced the most improved treatment responses and fewest withdrawals due to PAEs.

Validation of a questionnaire for asthma case identification in pre-schools in Latin America

BACKGROUND AND OBJECTIVE

We recently developed and validated a screening questionnaire for determining which school-aged children may need further investigation to diagnose and manage asthma. In the present study we sought to extend this to pre-school aged children.

METHODS

Questions from the school-aged questionnaire and literature on pre-school asthma were used to inform a focus group of parents with pre-school-aged children with asthma to develop a screening questionnaire. Parents of children attending 6 randomly selected kindergartens in Trelew, Argentina (n = 639) were invited to respond to the questionnaire. A reliability test-retest was undertaken in 187 randomly selected parents who completed the same questionnaire twice within 2-5 weeks. Clinical assessment included a standardized history and physical examination, spirometry before and after a β-agonist inhaler, and chest X-ray. Asthma was diagnosed by the pulmonologist.

RESULTS

Completed surveys were returned for 620 children, 607 of whom underwent clinical evaluation. The mean age was 4.21 years (range of 3.01-5.50) and included 82.5% white and 49.4% male children. Asthma was diagnosed in 103 (17.0%) children); 72 (69.9%) of these children did not have a previous diagnosis of asthma. The specificity, sensitivity, positive predictive value and negative predictive value of the questionnaire were 93.2%, 86.1%, 57.8% and 98.4%, respectively.

CONCLUSIONS

We have demonstrated the utility of a screening questionnaire for identifying pre-school-aged children who may benefit from further assessment for asthma.

Asthma Does Not Always Have a Reversible Airflow Obstruction: A Case Study and a Family Physician Perspective

Asthma has traditionally been seen as a treatment-responsive and reversible inflammatory process, while COPD has been characterised by fixed airway narrowing and alveolar destruction not responsive to treatment. However, in the past two decades there has been increasing evidence on the airway non-reversibility of asthma especially among the elderly patients. This condition has been referred to as overlap syndrome, as they have overlapping features of asthma and COPD. Our case study illustrates the fact that daily high inhaled corticosteroids are the mainstay of treatment, and co-management of such patients with our respiratory colleagues is crucial in stabilising this disease.

μ-chain-deficient mice possess B-1 cells and produce IgG and IgE, but not IgA, following systemic sensitization and inhalational challenge in a fungal asthma model

Allergic bronchopulmonary aspergillosis is often difficult to treat and results in morbidity associated with chronic airway changes. This study assessed the requirement for B cells and their products in the allergic pulmonary phenotype in a murine model of fungal allergic asthma that mimics allergic bronchopulmonary aspergillosis. C57BL/6 and μMT mice (assumed to lack peripheral B cells) were sensitized with Aspergillus fumigatus extract and challenged with two inhalation exposures of live conidia to induce airway disease. Airway hyperresponsiveness after methacholine challenge, peribronchovascular inflammation, goblet cell metaplasia, and fibrotic remodeling of the airways was similar between μMT mice and their wild-type counterparts (C57BL/6). Surprisingly, even in the absence of the μ-chain, these μMT mice produced IgE and IgG Abs, although the Abs induced did not have specificity for A. fumigatus Ags. In contrast, IgA was not detected in either the lavage fluid or serum of μMT mice that had been exposed to A. fumigatus. Our findings also reveal the existence of CD19(+)CD9(+)IgD(+) B-1 cells in the lungs of the μMT animals. These data show the μMT mice to have a developmental pathway independent of the canonical μ-chain route that allows for their survival upon antigenic challenge with A. fumigatus conidia, although this pathway does not seem to allow for the normal development of Ag-specific repertoires. Additionally, this study shows that IgA is not required for either clearance or containment of A. fumigatus in the murine lung, as fungal outgrowth was not observed in the μMT animals after multiple inhalation exposures to live conidia.

Persistent airflow obstruction in young adult asthma patients

BACKGROUND

Lung function determined by spirometry and the severity of dyspnea correlate weakly in asthma patients. We attempted to determine the risk factors in asthma patients having persistent airway obstruction despite of having only mild subjective symptoms, and to examine the possibility of improving FEV1 by treating asthma on the basis of the bronchodilator change in FEV1.

METHODS

We examined asthma patients in their 20s and who visited Sagamihara National Hospital for the first time over a period of four years, by reviewing their clinical records. They underwent tests on the bronchodilator change in FEV1 and a test of airway hyperresponsiveness to histamine dihydrochloride.

RESULTS

One hundred thirty-eight subjects (mean age, 25.6 years; 51 males, 87 females; current smoking, 30.4%; history of childhood asthma, 48.6%) were enrolled. Among them, 18.8% (26/138) showed persistent airway obstruction (postbronchodilator FEV1/FVC (%) <80%). Using the multiple logistic regression model, we found that history of childhood asthma and smoking history were the significant isolated risk factors for persistent airway obstruction. Moreover, we determined that the factors associated with the reversibility of airway obstruction in asthma patients without subjective symptoms were history of childhood asthma.

CONCLUSIONS

In this study, patients not undergoing treatment for asthma were examined. History of childhood asthma and smoking history may be the risk factors for persistent airway obstruction in the asthma patients with mild subjective symptoms. Tests on the bronchodilator change in FEV1 should be performed in patients with history of childhood asthma and smoking history, even if they have only mild subjective symptoms.

High-affinity IgE receptors on dendritic cells exacerbate Th2-dependent inflammation

The IgE-mediated and Th2-dependent late-phase reaction remains a mechanistically enigmatic and daunting element of human allergic inflammation. In this study, we uncover the FcεRI on dendritic cells (DCs) as a key in vivo component of this form of allergy. Because rodent, unlike human, DCs lack FcεRI, this mechanism could be revealed only by using a new transgenic mouse model with human-like FcεRI expression on DCs. In the presence of IgE and allergen, FcεRI(+) DCs instructed naive T cells to differentiate into Th2 cells in vitro and boosted allergen-specific Th2 responses and Th2-dependent eosinophilia at the site of allergen exposure in vivo. Thus, FcεRI on DCs drives the cascade of pathogenic reactions linking the initial allergen capture by IgE with subsequent Th2-dominated T cell responses and the development of late-phase allergic tissue inflammation.

Fms-like tyrosine kinase 3 ligand decreases T helper type 17 cells and suppressors of cytokine signaling proteins in the lung of house dust mite-sensitized and -challenged mice

We previously reported that Fms-like tyrosine kinase 3 ligand (Flt3-L) reversed airway hyperresponsiveness (AHR) and airway inflammation, and increased the number of regulatory CD11c(high)CD8α(high)CD11b(low) dendritic cells and CD4(+)CD25(+)ICOS(+)Foxp3(+)IL-10(+) T-regulatory cells in the lung of allergen-sensitized and -challenged mice. In this study, we evaluated the effect of Flt3-L on Th17 cells and expression of suppressors of cytokine signaling (SOCS) proteins in the lungs of house dust mite (HDM)-sensitized and -challenged mice. BALB/c mice were sensitized and challenged with HDM, and AHR to methacholine was established. Mice were treated with Flt3-L (5 μg, intraperitoneal) daily for 10 days. Levels of IL-4, -5, -6, -8, and -13, and transforming growth factor (TGF)-β in the bronchoalveolar lavage fluid (BALF) were examined by ELISA. Flt3-L treatment reversed existing AHR to methacholine and substantially decreased eosinophils, neutrophils, IL-5, -6, -8, and IL-13, and TGF-β levels in the BALF. HDM-sensitized and -challenged mice showed a significant increase in lung CD4(+)IL-17(+)IL-23R(+)CD25⁻ T cells with high expression of retinoic acid-related orphan receptor (ROR)-γt transcripts. However, administration of Flt3-L substantially decreased the number of lung CD4(+)IL-17(+)IL-23R(+)CD25⁻ T cells, with significantly decreased expression of ROR-γt mRNA in these cells. HDM sensitization caused a significant increase in the expression of SOCS-1, -3, and -5 in the lung. Flt3-L treatment abolished the increase in SOCS-1 and SOCS-3 proteins, whereas SOCS-5 expression was significantly reduced. These data suggest that the therapeutic effect of Flt3-L in reversing the hallmarks of allergic asthma in a mouse model is mediated by decreasing IL-6 and TGF-β levels in the BALF, which, in turn, decrease CD4(+)IL-17(+)IL-23R(+)ROR-γt(+)CD25⁻ T cells and the expression of SOCS-1 and SOCS-3 in the lung of HDM-sensitized and -challenged mice.