Inhaled corticosteroid effects both eosinophilic and non-eosinophilic inflammation in asthmatic patients

Modelling ASthma TrEatment Responses (MASTER): Effect of individual patient characteristics on the risk of exacerbation in moderate or severe asthma: A time-to-event analysis of randomized clinical trials

AIMS

There is limited understanding of how clinical and demographic characteristics are associated with exacerbation risk in patients with moderate-to-severe asthma, and how these factors correlate with symptom control and treatment response. Here we assess the relationship between baseline characteristics and exacerbation risk during regular dosing with inhaled corticosteroids (ICS) monotherapy or in combination with long-acting beta2-agonists (ICS/LABA) in clinical trial patients with varying levels of symptom control, as assessed by the asthma control questionnaire (ACQ-5).

METHODS

A time-to-event model was developed using pooled patient data (N = 16 282) from nine clinical studies [Correction added on 26 July 2023, after first online publication: The N value in the preceding sentence has been corrected in this version.]. A parametric hazard function was used to describe the time-to-first exacerbation. Covariate analysis included the assessment of the effect of seasonal variation, clinical and demographic baseline characteristics on baseline hazard. Predictive performance was evaluated by standard graphical and statistical methods.

RESULTS

An exponential hazard model best described the time-to-first exacerbation in moderate-to-severe asthma patients. Body mass index, smoking status, sex, ACQ-5, % predicted forced expiratory volume over 1 s (FEV1 p) and season were identified as statistically significant covariates affecting baseline hazard irrespective of ICS or ICS/LABA use. Fluticasone propionate/salmeterol (FP/SAL) combination therapy resulted in a significant reduction in the baseline hazard (30.8%) relative to FP monotherapy.

CONCLUSIONS

Interindividual differences at baseline and seasonal variation affect the exacerbation risk independently from drug treatment. Moreover, it appears that even when a comparable level of symptom control is achieved in a group of patients, each individual may have a different exacerbation risk, depending on their baseline characteristics and time of the year. These findings highlight the importance of personalized interventions in moderate-to-severe asthma patients.

Exhaled and Nasal Nitric Oxide - Impact for Allergic Rhinitis

FeNO measurement is a validated non-invasive technique, which is used for diagnosis and monitoring of asthma. It would be desirable to find a reliable method to monitor allergic rhinitis (AR) via measurement of FeNO, and/or nasal nitric oxide (nNO). The aim of our study was the assessment of the efficacy of FeNO and nNO as markers in AR treatment. FeNO and nNO were measured with the portable NO analyser (NIOX MINO®) in healthy participants and in patients with AR. The patients were examined during the pollen season and out of it. The effect of local corticosteroids and antihistamine therapy was observed in patients with AR during pollen season after three weeks of therapy. There are significant differences between FeNO and nNO in patients with AR compared to healthy controls at all set points of measurements. While FeNO responded well to the treatment with both antihistamines and combined therapy, nNO decreased only after combined therapy with antihistamines and nasal corticosteroids. nNO monitoring alone is not a suitable method to monitor inflammation of the upper airways in AR and its suppression by anti-allergic treatment and should be correlated with other markers as FeNO or symptom scores.

Effect of IL‑7 on Th17 cell responses in a mouse model of neutrophilic asthma

Neutrophilic asthma (NA) is characterized by neutrophil-mediated inflammation and the presence of Th17 cells. However, the mechanisms underlying Th17 cell responses in NA remain unknown. The aim of the present study was to examine the effects of interleukin (IL)-7 on Th17 cell responses in NA. A NA mouse model was sensitized by airway delivery of ovalbumin (OVA) and lipopolysaccharide and challenged with 1% OVA aerosol from day 21 for 3 consecutive days. Airway resistance was then measured to assess airway hyper-responsiveness (AHR). Cells from bronchoalveolar lavage fluid (BALF) underwent Diff-Quick and hematoxylin and eosin staining for classification. The levels of IL-17 in the BALF were determined by ELISA. The effects of IL-7 administration and STAT5 inhibition on Th17 cells were also characterized in vitro using splenic CD4⁺ T cells. Ki-67, Bcl-2 and activated caspase-3 expression in differentiated Th17 cells were analyzed by flow cytometry. The mouse model of NA was characterized by increased AHR, elevated levels of IL-17, high neutrophil counts in BALF, accumulated inflammatory cells in the lung and Th17 cell responses. IL-7 promoted the expression of Ki-67 and Bcl-2 while reducing caspase-3 expression. STAT5 inhibitor treatment decreased the levels of Ki-67 and Bcl-2, and resulted in increased expression of caspase-3. These results suggested that the IL-7/JAK/STAT5 signaling pathway may be involved in Th17 cell responses in NA.

Mast Cells and Their Progenitors in Allergic Asthma

Mast cells and their mediators have been implicated in the pathogenesis of asthma and allergy for decades. Allergic asthma is a complex chronic lung disease in which several different immune cells, genetic factors and environmental exposures influence the pathology. Mast cells are key players in the asthmatic response through secretion of a multitude of mediators with pro-inflammatory and airway-constrictive effects. Well-known mast cell mediators, such as histamine and bioactive lipids are responsible for many of the physiological effects observed in the acute phase of allergic reactions. The accumulation of mast cells at particular sites of the allergic lung is likely relevant to the asthma phenotype, severity and progression. Mast cells located in different compartments in the lung and airways have different characteristics and express different mediators. According to in vivo experiments in mice, lung mast cells develop from mast cell progenitors induced by inflammatory stimuli to migrate to the airways. Human mast cell progenitors have been identified in the blood circulation. A high frequency of circulating human mast cell progenitors may reflect ongoing pathological changes in the allergic lung. In allergic asthma, mast cells become activated mainly via IgE-mediated crosslinking of the high affinity receptor for IgE (FcεRI) with allergens. However, mast cells can also be activated by numerous other stimuli e.g. toll-like receptors and MAS-related G protein-coupled receptor X2. In this review, we summarize research with implications on the role and development of mast cells and their progenitors in allergic asthma and cover selected activation pathways and mast cell mediators that have been implicated in the pathogenesis. The review places an emphasis on describing mechanisms identified using in vivo mouse models and data obtained by analysis of clinical samples.

Differential effects of postoperative oral corticosteroid on eosinophilic vs. non-eosinophilic CRSwNP subtypes

PURPOSE

The efficacy of postoperative oral corticosteroids on surgical outcomes in chronic rhinosinusitis with nasal polyps (CRSwNP) patients following endoscopic sinus surgery (ESS) remains controversial. This study evaluated the potential benefits of postoperative oral corticosteroids on surgical outcomes in CRSwNP patients and investigated the differential effects on eosinophilic CRSwNP (ECRSwNP) and noneosinophilic CRSwNP (NECRSwNP).

MATERIALS AND METHODS

Patients with bilateral CRSwNP who underwent ESS were enrolled and randomized to receive either oral prednisolone (30 mg/day) or placebo for 2 weeks after surgery. Visual analog scale (VAS) and Sino-Nasal Outcome Test 22 (SNOT-22) scores were chosen as the subjective outcomes, evaluated at preoperative baseline and 1, 3, and 6 months postoperatively. Lund-Kennedy Endoscopic Scores (LKESs) were used as the objective outcome, evaluated at preoperative baseline and at 2 weeks and 2, 3, and 6 months postoperatively.

RESULTS

In total, 100 patients with bilateral CRSwNP were enrolled, of whom only 82 completed the 6-month follow-up. The subjective outcomes showed no significant difference at each follow-up points. Of the objective outcomes, the corticosteroid group reporting a trend of improvement in LKESs at 6 months postoperatively (p = 0.05). After stratification by tissue eosinophils, only patients with NECRSwNP (<10 eosinophils/HPF) demonstrated a significant improvement in LKESs at 3 months postoperatively (p = 0.03).

CONCLUSIONS

Postoperative oral corticosteroids did not provide additional improvements in VAS and SNOT-22 scores; nevertheless, a trend of LKES improvement was noted at 6 months postoperatively. After stratification by tissue eosinophils, this effect was significant only among NECRSwNP patients at 3 months follow-up.

Sputum interleukin-25 correlates with asthma severity: a preliminary study

Introduction

Interleukin 25 is an epithelial-derived cytokine associated with allergic Th2 inflammation. However, little is known about the role of IL-25 in different asthma phenotypes and its relationship with disease severity.

Aim

To evaluate and compare the mRNA and protein expression of IL-25 in patients with mild-to moderate/severe asthma and cough variant asthma (CVA).

Material and methods

Thirty-eight patients with stable asthma (11 patients with mild-to-moderate asthma, 14 patients with severe asthma and 13 patients with CVA) and 14 control subjects were enrolled. IL-25 protein concentration was measured in induced sputum (IS) supernatants by ELISA and IL-25 mRNA expression was evaluated in IS cells by real time PCR.

Results

No differences in IS IL-25 mRNA and IL-25 concentration between controls and the whole asthma group were found. In the detailed analysis, a lower IL-25 mRNA expression in sputum cells was observed in severe asthma compared to CVA and controls. IL-25 protein concentration in sputum supernatants was elevated in patients with severe asthma compared to controls, CVA and mild-to-moderate asthma. A sputum IL-25 level was increased in atopic vs. non-atopic asthma patients. The elevated IL-25 mRNA expression and protein concentration was associated with a lower eosinophil and higher neutrophil percentage in asthmatic airways.

Conclusions

Our results suggest that IL-25 is particularly associated with severe asthma. The relationship between IL-25 and neutrophilic airway inflammation suggests the pleiotropic role of IL-25 in the immune response in this disease.

Expression of Inflammatory Mediators in Induced Sputum: Comparative Study in Asthma and COPD

Asthma and COPD are the most common obstructive lung diseases characterized by inflammation in the lower airways which contribute to airflow limitation. Different inflammatory mediators are thought to play a key role in these diseases. This study was conducted in 13 patients with asthma, 12 patients with COPD, and 13 control subjects. The expression of mRNA of IL-6, IL-13, CXCL8, TSLP, IL-33, IL-25, IL-17, ECP, mast cell tryptase, CCL24, and CCL26 was assessed in induced sputum cells by real time PCR. We found that CXCL8 was strongly related to the neutrophil percentage but differed significantly in COPD and asthma patients. The expression of IL-17 was lower in patients with atopic asthma compared to non-atopic asthma. The percentage of macrophages correlated negatively with the expression of mast cell tryptase and ECP in COPD, and with CXCL8 in asthma. The expression of ECP correlated negatively with the severity of COPD symptoms measured by CAT. We conclude that asthma and COPD demonstrate a significant overlap in the airway cytokine profile. Thus, differentiation between the two diseases is difficult as based on a single cytokine, which suggests the coexistence of phenotypes sharing a common cytokine network in these obstructive lung diseases.

WNT/β-catenin pathway modulates the TNF-α-induced inflammatory response in bronchial epithelial cells

In this study, TNF-α was found to activate the WNT/β-catenin pathway in BEAS-2B human bronchial epithelial cells. Levels of phospho-LRP6, Dvl-2, and phospho-GSK-3β were elevated, while that of Axin was reduced by TNF-α treatment. Nuclear translocation of β-catenin and the reporter activity of a β-catenin-responsive promoter were increased by TNF-α treatment. Under the same experimental conditions, TNF-α activated the NF-κB signaling, which includes the phosphorylation and degradation of IκB and nuclear translocation and target DNA binding of NF-κB, and it was found that an inhibitor of NF-κB activation, JSH-23, inhibited TNF-α-induced Wnt signaling as well as NF-κB signaling. It was also found that recombinant Wnt proteins induced NF-κB nuclear translocations and its target DNA binding, suggesting that Wnt signaling and NF-κB signaling were inter-connected. TNF-α-induced modulations of IκB and NF-κB as well as pro-inflammatory cytokine expression were significantly suppressed by the transfection of β-catenin siRNA compared to that of control siRNA. Transfection of a β-catenin expression plasmid augmented the TNF-α-induced modulations of IκB and NF-κB as well as pro-inflammatory cytokine expression. These results clearly demonstrated that the WNT/β-catenin pathway modulates the inflammatory response induced by TNF-α, suggesting that this pathway may be a useful target for the effective treatment of bronchial inflammation.

Leukotriene B4 levels in sputum from asthma patients

Poor asthma control is associated with increased airway neutrophils. Leukotriene B4 (LTB4) is a potent neutrophil chemoattractant. We examined the levels of LTB4 levels in the sputum of asthma patients and the relationship with disease severity.

47 asthma patients (categorised according to Global Initiative for Asthma treatment stage) and 12 healthy controls provided sputum samples that were processed first with PBS to obtain supernatants and secondly with dithiothreitol (DTT) to obtain supernatants. LTB4 levels were determined by ELISA.

LTB4 levels were significantly higher in step 1 (steroid naïve) and step 3 (inhaled corticosteroid (ICS) plus long acting β-agonist) patients than step 2 patients (ICS alone) (p=0.02 and p=0.01, respectively). There was very good correlation when comparing PBS processed to DTT processed supernatants.

High LTB4 levels were found in the sputum of asthmatics at step 3 despite ICS use.

The levels of LTB4 are increased in the sputum of subgroups of asthma patientshttp://ow.ly/Xu6I303jVb5

Classification of Asthma Based on Nonlinear Analysis of Breathing Pattern

Normal human breathing exhibits complex variability in both respiratory rhythm and volume. Analyzing such nonlinear fluctuations may provide clinically relevant information in patients with complex illnesses such as asthma. We compared the cycle-by-cycle fluctuations of inter-breath interval (IBI) and lung volume (LV) among healthy volunteers and patients with various types of asthma. Continuous respiratory datasets were collected from forty age-matched men including 10 healthy volunteers, 10 patients with controlled atopic asthma, 10 patients with uncontrolled atopic asthma, and 10 patients with uncontrolled non-atopic asthma during 60 min spontaneous breathing. Complexity of breathing pattern was quantified by calculating detrended fluctuation analysis, largest Lyapunov exponents, sample entropy, and cross-sample entropy. The IBI as well as LV fluctuations showed decreased long-range correlation, increased regularity and reduced sensitivity to initial conditions in patients with asthma, particularly in uncontrolled state. Our results also showed a strong synchronization between the IBI and LV in patients with uncontrolled asthma. Receiver operating characteristic (ROC) curve analysis showed that nonlinear analysis of breathing pattern has a diagnostic value in asthma and can be used in differentiating uncontrolled from controlled and non-atopic from atopic asthma. We suggest that complexity analysis of breathing dynamics may represent a novel physiologic marker to facilitate diagnosis and management of patients with asthma. However, future studies are needed to increase the validity of the study and to improve these novel methods for better patient management.

Non-eosinophilic airway hyper-reactivity in mice, induced by IFN-γ producing CD4(+) and CD8(+) lung T cells, is responsive to steroid treatment

Non-eosinophilic asthma is characterized by infiltration of neutrophils into the lung and variable responsiveness to glucocorticoids. The pathophysiological mechanisms have not been characterized in detail. Here, we present an experimental asthma model in mice associated with non-eosinophilic airway inflammation and airway hyper-responsiveness (AHR). For this, BALB/c mice were sensitized by biolistic DNA immunization with a plasmid encoding the model antigen β-galactosidase (pFascin-βGal mice). For comparison, eosinophilic airway inflammation was induced by subcutaneous injection of βGal protein (βGal mice). Intranasal challenge of mice in both groups induced AHR to a comparable extent as well as recruitment of inflammatory cells into the airways. In contrast to βGal mice, which exhibited extensive eosinophilic infiltration in the lung, goblet cell hyperplasia and polarization of CD4(+) T cells into Th2 and Th17 cells, pFascin-βGal mice showed considerable neutrophilia, but no goblet cell hyperplasia and a predominance of Th1 and Tc1 cells in the airways. Depletion studies in pFascin-βGal mice revealed that CD4(+) and CD8(+) cells cooperated to induce maximum inflammation, but that neutrophilic infiltration was not a prerequisite for AHR induction. Treatment of pFascin-βGal mice with dexamethasone before intranasal challenge did not affect neutrophilic infiltration, but significantly reduced AHR, infiltration of monocytes and lymphocytes as well as content of IFN-γ in the bronchoalveolar fluid. Our results suggest that non-eosinophilic asthma associated predominantly with Th1/Tc1 cells is susceptible to glucocorticoid treatment. pFascin-βGal mice might represent a mouse model to study pathophysiological mechanisms proceeding in the subgroup of asthmatics with non-eosinophilic asthma that respond to inhaled steroids.

The Value of Induced Sputum in the Diagnosis and Management of Children with Bronchial Asthma

Background

Induced sputum in children with bronchial asthma represents a non-invasive method of bronchial inflammation assessment. The main objective of our study was to analyze the cellularity of sputum in patients with bronchial asthma according to the level of disease control and the controlling therapy (with/without inhaled glucocorticoids). The second objective was to establish the correlation between sputum cellularity and other indirect parameters used to evidence bronchial inflammation (exhaled nitric oxide) and obstruction (forced expiratory volume in 1 second).

Methods

The study included children with bronchial asthma that were assessed clinically (physical exam, questionnaire on the control of bronchial asthma in children) and by medical tests (induced sputum, exhaled nitric oxide, spirometry).

Results

In patients with partially controlled asthma and those with uncontrolled asthma, the eosinophils percentage in the sputum was higher than in patients with controlled asthma (19.8±26.4% respectively 9.2±20.5% versus 4.5±14.6%, p<0.001). Higher percentage of neutrophils in the sputum was found in the partially controlled and uncontrolled asthma than in the controlled asthma (43.9±20.1% respectively 51.6±38.3% versus 35±19.7%, p=0.009). We also evidenced a direct and statistically significant correlation between the exhaled nitric oxide and the neutrophils percentage in the sputum (r=0.67, p=0.0003). Also, an indirect, moderate to good correlation (r=−0.56, p=0.005) was evidenced between the values of the forced expiratory volume in 1 second and the high eosinophils percentage in the sputum.

Conclusions

In partially controlled and uncontrolled bronchial asthma the eosinophils and neutrophils count in the sputum is significantly higher than in patients with controlled asthma. There is an indirect correlation between the high eosinophils count in the sputum and the forced expiratory volume in 1 second, as well as a direct correlation between the neutrophils count and the exhaled nitric oxide, suggesting that induced sputum should be used in combination with other indirect parameters for the evidence of bronchial inflammation.

[Determining asthma treatment in children by monitoring fractional exhaled nitric oxide, sputum eosinophils and leukotriene B₄]

Sputum eosinophils and exhaled fractional nitric oxide (FENO) are markers of airway inflammation in asthma. Cytokines, cysteinyl-leukotrienes and leukotriene B4 (LTB4) are responsible for this inflammation. The aim of this study is to determine the usefulness of these markers in monitoring asthma treatment in children. FENO, sputum eosinophils, and LTB4 in induced sputum were performed in 10 children (9-15 years old). These determinations were repeated four months later, after the beginning or an increase in the treatment. FENO values tended to decrease (P=.15), pulmonary function tended to improve (P=.10), and sputum eosinophils decreased (P=.003) compared to the first determination. There were no differences in LTB4 concentrations (P=.88). Sputum eosinophils seem to be more precise than FENO in the monitoring of inflammation in asthmatic children.

The role of exhaled nitric oxide assessment in children with bronchial asthma

BACKGROUND

Exhaled nitric oxide (eNO) assessment in children with bronchial asthma (BA) is an easy and non-invasive test that provides informations on the presence of bronchial inflammation.

METHODS

The study included 110 children aged between 5-18 years with a diagnosis of BA. The patients were assessed clinically (objective examination, questionnaire regarding the disease control) and by medical tests (exhaled breath analysis for nitric oxide, induced sputum, spirometry).

RESULTS

Of the 33 patients with non-atopic BA, 9 (27.27%) presented normal eNO values, and 24 (72.72%) had higher than normal levels. There were 26 patients with controlled BA, 59 with partially controlled BA and 25 with uncontrolled BA, the levels of eNO demonstrating the existence of the statistically significant differences between the mean values of the variables obtained in the studied groups (p=0.003). Increased individual values were more frequently noted in patients with an exacerbation of asthma in the last month (70% vs 56.6%), but the differences were not statistically significant. Of the 77 patients with atopic BA, 35 (45.45%) had normal eNO, while 42 (54.54%) had increased values. The normal values of the eNO were most frequently noted in patients undergoing treatment with inhaled glucocorticoids (IGC). Patients with low percent of eosinophils in sputum had increased eNO values (p=0.03).

CONCLUSIONS

The investigation of the airways by measuring the eNO levels is a useful method of assessing bronchial inflammation in children with bronchial asthma, in order to establish the disease responsiveness and therapy.

Prostanoid DP receptor antagonists suppress symptomatic asthma-like manifestation by distinct actions from a glucocorticoid in rats

While inhaled glucocorticoids are the best treatment for the majority of chronic asthmatics, there is a small group who do not respond to these drugs or whose disease can only be controlled by high doses of oral glucocorticoids with risks of severe side effects. Therefore, a safe novel anti-asthmatic agent which has a different mechanism from that of glucocorticoids is needed for the management of asthma. We have previously shown that an orally active prostanoid DP receptor antagonist, S-5751, had potent anti-inflammatory effects in guinea pig and sheep asthma models. In this study, using a rat asthma like model, we found that lung neutrophilia and proinflammatory cytokine secretion as well as bronchial hyperresponsiveness and lung eosinophilia were induced by repeated antigen-inhalations after antigen-sensitization. These symptoms are similar to the pathogenesis of symptomatic asthma. Orally-administered prostanoid DP receptor antagonists S-5751 and pinagladin significantly suppressed not only bronchial hyperresponsiveness and lung eosinophilia but also neutrophilia and mucus secretion in the lung, while oral prednisolone inhibited only bronchial hyperresponsiveness and eosinophil infiltration. In addition, prostanoid DP receptor antagonists significantly suppressed interleukin (IL)-1β, IL-6 and CXCL1 mRNA in contrast to suppression of IL-4 and CCL11 mRNA by prednisolone. The majority of prostanoid DP receptor-expressing cells in both rat and human asthmatic lungs are infiltrative macrophages and/or monocytes. These results suggest that prostanoid DP receptor antagonists utilize different mechanisms from glucocorticoids, and that they would be a novel alternative and/or combination drug for asthma therapy.

Neutrophilic Cells in Sputum of Allergic Asthmatic Children

Airway inflammation is regarded as a central feature of asthma and is mostly sustained by eosinophilic infiltrate. Recent studies have shown that a co-activation of eosinophil- and neutrophil-dependent inflammatory mechanisms might explain why some asthmatics do not respond to conventional asthma therapy. The aim of our study is to determine whether neutrophilic inflammation was involved in 55 allergic children with mild-moderate persistent asthma and the relationship with the response to steroid treatment. Before the sputum analysis, all children underwent spirometry with the reversibility test, and were divided into two groups on the basis of the response (such as >12% of baseline FEV1): group 1 positive and group 2 negative. Eosinophil cationic protein concentrations were measured by radioimmunoassay and neutrophyl myeloperoxidase (MPO) concentrations were measured by an MPO-EIA. Ten healthy children of comparable ages served as control group. Total IgE, FEV1 and FEV/FVC values were similar in both groups. The sputum macrophage count was higher in controls than in allergic asthmatics, but there was no difference between groups 1 and 2 (59.6% vs 18.3% and 17%; p≤ 0.005). Sputum neutrophils were significantly higher in group 2 both vs controls (62% vs 34%; p≤ 0.005) and vs group 1 (62% vs 37%; p≤ 0.005). Our data suggest that neutrophils are involved in airway allergic inflammation in mild-moderate persistent childhood asthma and a high neutrophil count in sputum may be related to a lower responsiveness to inhaled corticosteroids.

Role of neurogenic substance P in overexpression of alveolar macrophages' neurokinin 1 receptor in mice exposed to cigarette smoke

Neurokinin 1 receptors (NK1Rs) in alveolar macrophages (AMs) are overexpressed by cigarette smoke (CS) in vivo and substance P (SP) in vitro. Because CS could stimulate pulmonary C-fibers (PCFs) to release SP, we asked whether this neurogenic SP was responsible for AMs' NK1R overexpression during CS. We compared pulmonary SP and AMs' NK1R gene and protein levels in intact and PCF-degenerated mice exposed to filtered air (FA) and CS. Pulmonary SP was increased by CS but almost eliminated by PCF degeneration, which closely correlated to the changes in AMs' NK1R expression. Moreover, SP was higher in the PCF-degenerated mice exposed to CS than FA. To evaluate the direct effects of CS and SP on the NK1R expression and the involvement of nuclear factor (NF)-kappaB, macrophages were exposed to CS condensate (CSC) and/or SP without or with blocking NK1R or inhibiting NF-kappaB activation in vitro. CSC itself induced a moderate secretion of SP from macrophages, and amplified NK1R responses to SP that were completely eliminated by blocking NK1R, and substantially reduced after inhibiting NF-kappaB. Our results suggest that CS produces AMs' NK1R overexpression primarily by both promoting neurogenic SP release and synergizing NK1R response to neurogenic SP largely via activating NF-kappaB pathway.

The utility of sputum eosinophils and exhaled nitric oxide for monitoring asthma control with special attention to childhood asthma

The monitoring of sputum eosinophils has received certain attention as a tool for improving asthma management both in children and in adults. The present paper reviews the technique and also the usefulness of induced sputum in the diagnosis and assessment of asthma, together with its ability to predict the response to treatment and to anticipate asthma exacerbations. Special attention is addressed to childhood asthma. The authors conclude that due to cost-effectiveness reasons derived from high labour costs, together with the unpleasantness of the technique and the failure to obtain adequate samples in a non-negligible percentage of children, this technique should be only used for research purposes.

Elevated urinary leukotriene E4 levels are associated with hospitalization for pain in children with sickle cell disease

Cysteinyl leukotrienes (CsyLTs) are inflammatory mediators produced by white blood cells. Leukotriene LTE(4) is the stable metabolite of CsyLTs, which can be measured in urine. We tested two hypotheses among children with sickle cell disease (SCD): (1) baseline urinary LTE(4) levels are elevated in children with SCD when compared with controls; and (2) baseline LTE(4) levels are associated with an increased incidence rate of hospitalization for SCD-related pain. Baseline LTE(4) levels were measured in children with SCD (cases) and children without SCD matched for age and ethnicity (controls). Medical records of cases were reviewed to assess the frequency of hospitalization for pain within 3 years of study entry. LTE(4) levels were obtained in 71 cases and 22 controls. LTE(4) levels were higher in cases compared with controls (median LTE(4): 100 vs. 57 pg/mg creatinine, P < 0.001). After adjustment for age and asthma diagnosis, a greater incidence rate of hospitalization for pain was observed among children with SCD in the highest LTE(4) tertile when compared with the lowest (114 vs. 52 episodes per 100 patient-years, P = 0.038). LTE(4) levels are elevated in children with SCD when compared with controls. LTE(4) levels are associated with an increased rate of hospitalizations for pain.

Th17 and allergy

The identification of novel helper T (Th) cell subsets, i.e., IL-17-producing Th cells (Th17 cells) and regulatory T cells (Treg cells), provided new insight into our understanding of the molecular mechanisms involved in the development of infectious and autoimmune diseases as well as immune responses, and thus led to revision of the classic Th1/Th2 paradigm. Several current lines of evidence from gene-deficient mice indicate that IL-17 and Th17 cells, but not IFN-gamma and Th1 cells, are responsible for the development of autoimmune diseases such as murine arthritis and encephalomyelitis, which have classically been considered to be Th1-mediated disorders. Th17 cells may also contribute to the pathogenesis of classically recognized Th2-mediated allergic disorders. In this review, we summarize the current knowledge regarding IL-17 and Th17 cells and discuss their potential roles in the pathogenesis of allergic disorders.

Mast cells in the promotion and limitation of chronic inflammation

Observations of increased numbers of mast cells at sites of chronic inflammation have been reported for over a hundred years. Light and electron microscopic evidence of mast cell activation at such sites, taken together with the known functions of the diverse mediators, cytokines, and growth factors that can be secreted by appropriately activated mast cells, have suggested a wide range of possible functions for mast cells in promoting (or suppressing) many features of chronic inflammation. Similarly, these and other lines of evidence have implicated mast cells in a variety of adaptive or pathological responses that are associated with persistent inflammation at the affected sites. Definitively characterizing the importance of mast cells in chronic inflammation in humans is difficult. However, mice that genetically lack mast cells, especially those which can undergo engraftment with wildtype or genetically altered mast cells, provide a means to investigate the importance of mast cells and specific mast cell functions or products in diverse models of chronic inflammation. Such work has confirmed that mast cells can significantly influence multiple features of chronic inflammatory responses, through diverse effects that can either promote or, perhaps more surprisingly, suppress aspects of these responses.

Loss of Control of Asthma Following Inhaled Corticosteroid Withdrawal Is Associated With Increased Sputum Interleukin-8 and Neutrophils

BACKGROUND

The role of neutrophils in exacerbations of asthma is poorly understood. We examined the effect of withdrawal of inhaled corticosteroids on sputum inflammatory indexes in a double-blind study in patients with moderate, stable asthma.

METHODS

Following a 2-week run in period, 24 subjects were randomized to receive either budesonide (400 microg bid) or placebo, and the study was continued for another 10 weeks.

RESULTS

Loss of asthma control developed in 8 of 12 patients over the 10-week period of steroid withdrawal, whereas only 1 of 10 patients with budesonide treatment had exacerbations. Those with an exacerbation had increased sputum interleukin (IL)-8 (p < 0.0001) and increased sputum neutrophil numbers (p < 0.0001) compared to those without an exacerbation. The significant elevation in sputum IL-8 and neutrophil counts initially occurred 2 weeks prior to an exacerbation. Sputum neutrophilia correlated positively with changes in IL-8 levels (r(2) = 0.76, p = 0.01).

CONCLUSIONS

Rapid withdrawal of inhaled corticosteroids results in an exacerbation of asthma that is preceded by an increase in sputum neutrophils and IL-8 concentrations, in contrast to an increase in eosinophils reported in previous studies in which inhaled steroids are slowly tapered.

Microarray profiling of lymphocytes in internal diseases with an altered immune response: potential and methodology

Recently it has become possible to investigate expression of all human genes with microarray technique. The authors provide arguments to consider peripheral white blood cells and in particular lymphocytes as a model for the investigation of pathophysiology of asthma, RA, and SLE diseases in which inflammation is a major component. Lymphocytes are an alternative to tissue biopsies that are most often difficult to collect systematically. Lymphocytes express more than 75% of the human genome, and, being an important part of the immune system, they play a central role in the pathogenesis of asthma, RA, and SLE. Here we review alterations of gene expression in lymphocytes and methodological aspects of the microarray technique in these diseases. Lymphocytic genes may become activated because of a general nonspecific versus disease-specific mechanism. The authors suppose that in these diseases microarray profiles of gene expression in lymphocytes can be disease specific, rather than inflammation specific. Some potentials and pitfalls of the array technologies are discussed. Optimal clinical designs aimed to identify disease-specific genes are proposed. Lymphocytes can be explored for research, diagnostic, and possible treatment purposes in these diseases, but their precise value should be clarified in future investigation.