Eosinophil cationic protein and interleukin-8 levels in bronchial lavage fluid from children with asthma and infantile wheeze

Regulation and directed inhibition of ECP production by human neutrophils

Background

Neutrophils are involved in the pathophysiology of allergic asthma, where the Eosinophil Cationic Protein (ECP) is a critical inflammatory mediator. Although ECP production is attributed to eosinophils, we reported that ECP is also present in neutrophils from allergic patients where, in contrast to eosinophils, it is produced in an IgE-dependent manner. Given the key role of ECP in asthma, we investigated the molecular mechanisms involved in ECP production as well as the effects induced by agonists and widely used clinical approaches. We also analyzed the correlation between ECP production and lung function.

Methods

Neutrophils from allergic asthmatic patients were challenged with allergens, alone or in combination with cytokines, in the presence of cell-signaling inhibitors and clinical drugs. We analyzed ECP levels by ELISA and confocal microscopy. Lung function was assessed by spirometry.

Results

IgE-mediated ECP release is dependent on phosphoinositide 3-kinase, the extracellular signal-regulated kinase (ERK1/2) and the production of reactive oxygen species by NADPH-oxidase. Calcineurin phosphatase and the transcription factor NFAT are also involved. ECP release is enhanced by the cytokines interleukin (IL)-5 and granulocyte macrophage-colony stimulating factor, and inhibited by interferon-γ, IL-10, clinical drugs (formoterol, tiotropium and budesonide) and allergen-specific IT. We also found an inverse correlation between asthma severity and ECP levels.

Conclusions

Our results suggest the molecular pathways involved in ECP production and potential therapeutic targets. We also provide a new method to evaluate disease severity in asthmatic patients based on the quantification of in vitro ECP production by peripheral neutrophils.

The relationship between inflammation and remodeling in childhood asthma: A systematic review

OBJECTIVES

We aimed to perform a systematic review of all studies with direct measurements of both airway inflammation and remodeling in the subgroup of children with repeated wheezing and/or persistent asthma severe enough to warrant bronchoscopy, to address whether airway inflammation precedes remodeling or is a parallel process, and also to assess the impact of remodeling on lung function.

METHODS

Four databases were searched up to June 2017. Two independent reviewers screened the literature and extracted relevant data.

RESULTS

We found 526 references, and 39 studies (2390 children under 18 years old) were included. Airway inflammation (eosinophilic/neutrophilic) and remodeling were not present in wheezers at a mean age of 12 months, but in older pre-school children (mean 2.5 years), remodeling (mainly increased reticular basement membrane [RBM] thickness and increased area of airway smooth muscle) and also airway eosinophilia was reported. This was worse in school-age children. RBM thickness was similar in atopic and non-atopic preschool wheezers. Airway remodeling was correlated with lung function in seven studies, with FeNO in three, and with HRCT-scan in one. Eosinophilic inflammation was not seen in patients without remodeling. There were no invasive longitudinal or intervention studies.

CONCLUSION

The relationship between inflammation and remodeling in children cannot be determined. Failure to demonstrate eosinophilic inflammation in the absence of remodeling is contrary to the hypothesis that inflammation causes these changes. We need reliable, non-invasive markers of remodeling in particular if this is to be addressed.

Biomarkers to predict asthma in wheezing preschool children

Wheezing in preschool children is a very common symptom. An adequate prediction of asthma in these children is difficult and cannot be reliably assessed with conventional clinical tools. The study of potential predictive biomarkers in various media, ranging from invasive sampling (e.g. bronchoscopy) to non-invasive sampling (lung function testing and exhaled breath analysis), was comprehensively reviewed. The evolution in biomarker discovery has resulted in an 'omics' approach, in which hundreds of biomarkers in the field of genomics, proteomics, metabolomics, and 'breath-omics' can be simultaneously studied. First, results on gene expression and exhaled breath profiles in predicting an early asthma diagnosis are promising. However, many hurdles need to be overcome before clinical implementation is possible. To reliably predict asthma in a wheezing child, probably a holistic approach is needed, combining clinical information with blood sampling, lung function tests, and potentially exhaled breath analysis. The further development of predictive, non-invasive biomarkers may eventually improve an early asthma diagnosis in wheezing preschool children and assist clinicians in early treatment decision-making.

The role of transforming growth factor-β1 in airway inflammation of childhood asthma

TGF-beta-targeting structural and inflammatory cells has been implicated in the mechanisms leading to the inflammatory and restructuring processes in asthma, suggesting an impact of TGF-beta1 signaling on the development and persistency of this disease. We investigated the potential early involvement of TGF-beta1 activity in the immunological and molecular mechanisms underlying progression of inflammation in childhood asthma. We evaluated the levels of TGF-beta1 in induced sputum supernatants (ISSs) and the expression of small mother cell against decapentaplegic (Smad) 2 and Smad7 proteins in induced sputum cells (ISCs) from children with intermittent asthma (IA), moderate asthma (MA) and control subjects (C). Furthermore, we investigated the regulatory role of TGF-beta1 activity on eosinophil and neutrophil adhesion to epithelial cells using adhesion assay, and on the granulocyte expression of adhesion molecule CD11b/CD18 Macrophage-1 antigen (MAC-1), by flow cytometry. We found that the levels of TGF-beta1 are increased in ISSs of IA and MA in comparison to C, concomitantly to the activation of intracellular signaling TGFbeta/Smads pathway in ISCs. In MA, TGF-beta1 levels correlated with the number of sputum eosinophils and neutrophils. Furthermore, we showed the ability of sputum TGF-beta1 to promote eosinophil and neutrophil adhesion to epithelial cells, and to increase the expression of MAC-1 on the granulocyte surface. This study shows the activation of TGFbeta/Smad signaling pathway in the airways of children with IA and, despite the regular ICS treatment, in children with MA, and provides evidence for the contribution of TGF-beta1 in the regulation of granulocyte activation and trafficking.

Limonene inhalation reduces allergic airway inflammation in Dermatophagoides farinae-treated mice

Limonene is one of the main flavonoids which is reported to inhibit the inflammatory response by suppressing the production of reactive oxygen species. The aim of this study was to evaluate whether limonene can inhibit Dermatophagoides farinae-induced airway hyperresponsiveness (AHR), eosinophilic infiltration and other histological changes in the lung, T helper (Th) 2 cytokine production and airway remodeling in a mice model of asthma. Treatment with limonene significantly reduced the levels of IL-5, IL-13, eotaxin, MCP-1, and TGF-β₁ in bronchoalveolar lavage fluid. The goblet cell metaplasia, thickness of airway smooth muscle, and airway fibrosis were markedly decreased in limonene-treated mice. Furthermore, AHR to acetylcholine was significantly abrogated in limonene-treated mice. These results indicate that limonene has a potential to reduce airway remodeling and AHR in asthma model.

Exhaled nitric oxide fractions are well correlated with clinical control in recurrent infantile wheeze treated with inhaled corticosteroids

Fractional exhaled nitric oxide (FeNO) is a non-invasive marker of bronchial inflammation in asthma. However, the interest of FeNO measurement remained limited in infantile wheeze. The aim of this prospective study was to evaluate the feasibility and reproducibility of FeNO off-line measurement in very young children with recurrent wheeze and to assess whether clinical control of infantile wheeze correlates with FeNO levels. Two exhalation samples were collected in mylar balloon during quite tidal breathing. FeNO measurements were performed off-line by a NO analyzer. The participating patients were aged ≤36 months, wheezes had started before the age of 24 months, and they were receiving maintenance treatment with inhaled corticosteroids for at least 3 months duration. The studied population comprised of 40 uncontrolled infants with persistent wheezy respiratory symptoms, median age 14.5 months, and 40 with optimal controlled infantile wheeze, median age 14 months. The reproducibility was excellent (r = 0.95; p < 0.0001). There was a significant difference in FeNO levels between the groups of persistent wheeze and well-controlled infants: 19.8 (2.5-99.3) ppb vs. 7.7 (0.6-29.5) ppb, p < 0.0001. At a FeNO level >15 ppb, the predictive values for uncontrolled disease were as follows: positive predictive value = 65%, negative predictive value = 90%. FeN0 levels were not increased by atopy or passive tobacco. Off-line assessment of FeNO is feasible, reproducible, and well accepted in wheezy very young children. Optimal clinical control of infantile wheeze appeared to be associated with the control of bronchial inflammation when evaluated by FeNO measurements.

Anti-inflammatory effects of limonene from yuzu (Citrus junos Tanaka) essential oil on eosinophils

Yuzu (Citrus junos Tanaka) has been used as a traditional medicine in Japan. We investigated in vitro anti-inflammatory effects of limonene from yuzu peel on human eosinophilic leukemia HL-60 clone 15 cells. To examine anti-inflammatory effects of limonene on the cells, we measured the level of reactive oxygen species (ROS), monocyte chemoattractant protein-1 (MCP-1), nuclear factor (NF) kappa B, and p38 mitogen-activated protein kinase (MAPK). We found that low concentration of limonene (7.34 mmol/L) inhibited the production of ROS for eotaxin-stimulated HL-60 clone 15 cells. 14.68 mmol/L concentration of limonene diminished MCP-1 production via NF-kappa B activation comparable to the addition of the proteasomal inhibitor MG132. In addition, it inhibited cell chemotaxis in a p38 MAPK dependent manner similar to the adding of SB203580. These results suggest that limonene may have potential anti-inflammatory efficacy for the treatment of bronchial asthma by inhibiting cytokines, ROS production, and inactivating eosinophil migration.

Markers of eosinophilic and neutrophilic inflammation in bronchoalveolar lavage of asthmatic and atopic children

BACKGROUND

Recent studies performing fiberoptic bronchoscopy in children have improved our understanding of asthma pathophysiology. Eosinophilic, but also neutrophilic, inflammation has been described in asthma, but the relationship with atopy was incompletely investigated. The aim of this study is to examine inflammatory cells and mediators in children with asthma compared to the appropriate controls, i.e. atopic children without asthma and children with no atopy or asthma. Moreover, asthmatic children were analysed separately based on the presence of atopy and stratified by age.

METHODS

We recruited 191 children undergoing fiberoptic bronchoscopy for appropriate indications: 91 asthmatics (aged 1.4-17 years), 44 atopics without asthma (1.6-17.8 years) and 56 nonasthmatic nonatopic controls (1.4-14 years). In bronchoalveolar lavage, total and differential cell counts and inflammatory mediators, including ECP, eotaxin, IL-8 and TNFalpha, were analysed.

RESULTS

Eosinophils and ECP levels were increased in asthmatic children when compared to controls (P = 0.002 and P = 0.01, respectively), but also atopic children without asthma had increased ECP levels compared to controls (P = 0.0001). Among asthmatic children, eosinophils and ECP levels were not different between atopic and nonatopic individuals. Neither neutrophils nor the related mediators (IL-8 and TNFalpha) differed significantly in the three groups. This pattern of inflammation was observed in both preschool and school-aged asthmatic children.

CONCLUSIONS

This study suggests that markers of eosinophilic, but not neutrophilic inflammation, are increased in asthmatic children and also in atopic children without asthma. Of interest, in asthmatic children, the activation of the eosinophilic response is not solely because of the presence of atopy.

The indication and effectiveness of low-dose erythromycin therapy in pediatric patients with bronchial asthma

To elucidate the mechanisms of intractable pediatric bronchial asthma and the indication of low-dose erythromycin (EM) therapy, the serum chemokine levels of and the angiogenic factor were evaluated in 55 pediatric patients with bronchial asthma; 7.4 +/- 3.5 yr old, who had been treated with inhaled steroid, leukotriene receptor antagonist, theophylline and others for more than a year. Both the levels of interleukin (IL) 8 (p = 0.036) and vascular endothelial growth factor (VEGF) (p = 0.005) were higher in patients with severe type than those of patients with the milder type, while other chemokine levels such as serum eotaxin and MCP1 did not show the correlation with the severity of bronchial asthma. Induction of therapy with low-dose EM induced improvement of the clinical symptoms in patients with severe type and decrease of their serum chemokine levels: IL8; from 736 +/- 88 to 75 +/- 85 pg/ml (p < 0.0005), and VEGF; from 352.0 +/- 160.5 to 132.2 +/- 59.9 pg/ml (p = 0.021) within the next 6 months. Moreover, low-dose EM resulted in a decreased daily peak-trough fluctuation rate of the serum theophylline concentration; (C(max )- C(min))/C(min), from 1.3 +/- 0.5 to 0.5 +/- 0.3, which led to the maintenance of effective serum levels. These results indicated that IL8 and VEGF affect the severity of standard therapies resistance intractable bronchial asthma. Through the suppression of these chemokines and maintenance of effective theophylline levels, low-dose EM therapy improves the symptoms of bronchial asthma.

Non-invasive markers of airway inflammation and remodeling in childhood asthma

To evaluate the relationship between pro-inflammatory and pro-remodeling mediators and severity and control of asthma in children, the levels of IL-8, MMP-9, TIMP-1 in induced sputum supernatants, the number of sputum eosinophils, as well as FeNO, were investigated in 35 asthmatic children, 12 with intermittent (IA) and 23 with moderate asthma (MA), and 9 controls (C). The patients with asthma were followed for 1 yr and sputum was obtained twice during the follow-up. Biomarker levels were correlated with the number of exacerbations. We found that IL-8, MMP-9, TIMP-1 and the numbers of eosinophils in induced sputum, as well as FeNO, were increased in children with IA and MA in comparison to C. The ongoing inflammation was confirmed by increased nuclear p65 NF-kappaB subunit localization in sputum cells. In MA, FeNO measurements, sputum eosinophils and IL-8 levels, positively correlated with the occurrence of disease exacerbations during a 1-yr follow-up. According to FeNO, sputum eosinophils and IL-8 sputum concentrations, and the number of exacerbations, two distinct phenotypes of MA were identified. This study shows that the presence of bronchial inflammation is detectable in the airways of some IA, as well as in the airways of MA, despite the regular ICS treatment. This study also proposes the need to perform large prospective studies to confirm the importance of measuring specific biomarkers in induced sputum, concomitantly to FeNO analyses, to assess sub-clinical airway inflammation and disease control in children with asthma.

Early intervention with suplatast tosilate for prophylaxis of pediatric atopic asthma: a pilot study

The onset of asthma may be related to Th2 cytokine dominance at the time when food allergies occur several months after birth. This study investigated the effectiveness of early intervention with a Th2 cytokine inhibitor (suplatast tosilate) for prevention of asthma in infants with food allergies and atopic dermatitis. Suplatast tosilate dry syrup (6 mg/kg daily) or a histamine H(1)-blocker (ketotifen fumarate dry syrup: 0.06 mg/kg daily) was administered randomly to 53 infants with atopic dermatitis caused by food allergies. The primary endpoints were the incidence of asthma and the time to the onset of wheezing. The peripheral blood Th1/Th2 ratio, total IgE level, and eosinophil count were measured before and after treatment. After 24 months of treatment, the prevalence of asthma was significantly lower in the suplatast group (20.8%) than in the ketotifen group (65.6%, p < 0.01). Additionally, the time from the start of treatment to the initial episode of wheezing for infants who developed asthma was significantly longer in the suplatast group than the ketotifen group (p < 0.01). Furthermore, the eosinophil count was significantly decreased by suplatast treatment (p < 0.05), and there was a significant difference between the suplatast and ketotifen groups with respect to both the eosinophil count (p < 0.01) and the Th1/Th2 ratio (p < 0.05). The results of the present pilot study suggest that suplatast tosilate is useful for the primary prevention of wheezing and asthma in children.

Disease surveillance using bronchoalveolar lavage

The role of pulmonary infection and inflammation in the pathogenesis of destructive lung disease in cystic fibrosis (CF) is undisputed. The use of bronchoscopy and bronchoalveolar lavage (BAL) has demonstrated that these processes may begin early in life and be present in the absence of overt clinical symptoms. Some children diagnosed following newborn screening can be infected with Pseudomonas aeruginosa in infancy. Studies using BAL have demonstrated a relationship between lower airway inflammation and bacterial load in the lungs; however, inflammation may occur in the absence of obvious current infection. BAL has the potential to provide a greater understanding of the pathogenesis of CF lung disease and microbiological surveillance provides the opportunity for early detection and eradication of P. aeruginosa. Lack of standardization inhibits the ability to compare data from different centres and to optimize treatment strategies. This review discusses the recommendations from a workshop held in early 2007 aimed at achieving a standardized approach to BAL in infants and young children with CF.

[What methods can we use to measure inflammation in the asthmatic child?]

Pulmonary function tests remain the best method to assess underlying bronchial inflammation, particularly distal airway flow. However, these tests are limited in their ability to differentiate treatment-reversible small airway obstruction from definitive remodeling related to a viral infection. The increased availability of the exhaled fraction of nitric oxide (FeNO) measurement means that this method is accessible and attractive. In spite of a number of studies, mainly in adults, its use in the management of asthma needs more investigation. Threshold values that permit optimum management are poorly defined, and strategies based on variations of FeNO do not result in reduction of the number of exacerbations, although they do permit better control of drug use and better control of inflammation. Sputum eosinophil counts are of interest for the prevention of exacerbations, although while not well validated they may be useful in some asthmatic children. Also, they require an experienced cytology laboratory. Finally, recent data on bronchial biopsies in children with difficult-to-treat asthma will be summarized.

Neutrophil but not eosinophil inflammation is related to the severity of a first acute epidemic bronchiolitis in young infants

Acute bronchiolitis is the main cause of emergency visits and hospitalizations in infants. Recent data suggest that neutrophil- and eosinophil-mediated inflammations were part of bronchiolitis pathophysiology. Apart from the defined risk factors, few was known on the underlying pathophysiology, which might point out the differences observed in the severity of the disease. The aim of this study was to assess whether the clinical severity of acute epidemic bronchiolitis in young infants might be related to a specific underlying inflammatory process. Total and differential cell counts, IL-8, eotaxin, eosinophil cationic protein (ECP) and albumin levels were assessed at the time of admission in bronchial secretions from 37 infants (median age 17 wk) with acute bronchiolitis. Outcome severity variables were: hypoxemia, Silverman score, tachypnea, feeding alteration, and duration of hospitalization. Neutrophils predominated, and eosinophils were present in 54% of the infants. IL-8 levels strongly correlated with ECP and albumin levels. Albumin levels were correlated with ECP and eotaxin levels. IL-8 levels were higher in infants with hypoxemia and inversely related with SaO(2) levels. IL-8 and albumin levels significantly rose with respiratory rate, and Silverman score. IL-8, albumin and ECP levels were significantly higher in infants hospitalized >/=7 days. Furthermore, IL-8 levels were correlated with the duration of hospitalization. Neither cell counts nor eotaxin levels were related to the severity criteria studied. This study suggests that IL-8-associated airway inflammation significantly contributed to the severity of acute epidemic bronchiolitis.

In vitro toxicity evaluation of diesel exhaust particles on human eosinophilic cell

Diesel exhaust particles (DEPs), comprised mainly of particles less than 2.5 microm (PM 2.5) in aerodynamic diameter, have been assumed to enhance the response of asthma to allergen inhalation. Although eosinophilic infiltration is remarkable in the event of bronchial asthma induced by DEPs, the precise mechanisms leading to eosinophilia are unknown. To examine the effect of DEPs on eosinophils, we measured the cytokine products and activity of nuclear factor-kappa B (NF-kappa B) after addition of the proteasomal inhibitor MG132 in HL-60 clone 15 cells differentiated into eosinophils. We measured eotaxin-induced chemotaxis of cells and their activity of p38 mitogen-activated protein (MAP) kinase was analysed. Interleukin (IL)-8 and monocyte chemoattractant protein-1 (MCP-1) were increased markedly in DEPs-treated cells. The active form of NF-kappaB in cells treated with DEPs was increased, and this effect was significantly decreased by the administration of MG132. Cell migration in the presence of DEPs was significantly greater, and inhibited by adding N-acetyl l-cysteine. P38 MAP kinase activity was highly influenced by DEPs-treatment. DEPs induce MCP-1 and IL-8 production by up-regulating NF-kappa B activity, which is inhibited in the presence of an inhibitor of proteasomal degradation. DEP also promotes eotaxin-induced chemotaxis in a p38-dependent manner.

Neutrophils as a novel source of eosinophil cationic protein in IgE-mediated processes

The production of eosinophil cationic protein (ECP) in IgE-mediated diseases has been associated mainly with eosinophils, although no IgE-dependent ECP release has been observed in these cells. Because there is increasing evidence of neutrophil participation in allergic processes, we have examined whether human neutrophils from allergic patients were able to produce ECP by an IgE-dependent mechanism. After challenge with specific Ags to which the patients were sensitized, ECP release was detected in the culture medium. Furthermore, intracellular protein was detected by flow cytometry, immunofluorescence staining, and Western blotting. Expression at both mRNA and de novo protein synthesis were detected, respectively, by RT-PCR and radiolabeling with (35)S. Ag effect was mimicked by cell treatment with anti-IgE Abs or Abs against FcepsilonRI and galectin-3 (FcepsilonRI>galectin-3), but not against FcepsilonRII. These observations represent a novel view of neutrophils as possible source of ECP in IgE-dependent diseases.

Bacterial colonization in respiratory secretions from acute and recurrent wheezing infants and children

Lower respiratory tract infection in childhood often results in airway obstruction, characterized by wheezing. However, contribution of bacterial colonization to the wheezy state in children remains unclear. Wheezing and non-wheezing children requiring hospitalization were classified into three groups: (i) wheezing children having a past history of recurrent wheezing; (ii) wheezing children without such history; and (iii) non-wheezing children as control subjects. Respiratory secretions as sputum were analyzed microscopically, and cultured. Cultured pathogenic bacterial species in sputum were categorized into two subgroups according to their amounts, i.e., dominant and non-dominant amounts of colonies. Incidence of bacterial colonization and wheezing were assessed. Hospitalized children were mainly 1- to 2-yr old, and rapidly decreased in number for older ages. Children in the three groups belonged to different clinical entities. Children in the recurrent wheezing group were highly sensitized to mite allergens, and still required hospitalization after 2 yr of age. Incidence of bacterial colonization was similar between the three groups. Dominant and non-dominant amounts of bacterial colonization were 170/997 (17.1%) and 170/997 (17.1%), respectively, in the recurrent wheezing group; 28/146 (19.2%) and 35/146 (24.0%), respectively, in the acute wheezing group; and 15/56 (26.8%) and 7/56 (12.5%), respectively, in the non-wheezing group. Regardless of the presence of wheezing, bacterial colonization commonly occurred at a young age in the three groups. In recurrent wheezing children, boys (122/611, 20.0%) carried non-dominant amounts of bacteria more frequently than girls (48/386, 12.4%) (p < 0.01). Boys showed predominant wheezing and susceptibility to bacterial colonization. Assessment of bacterial colonization allowed us to characterize asthma onset and outgrowth in childhood.

Age and sex as factors of response to RSV infections among those with previous history of wheezing

Although enhanced immune reaction caused by the respiratory syncytial virus (RSV) in allergen-sensitized animal model has been reported, RSV illnesses in children already sensitized or having recurrent wheezing episodes have not been completely studied. In addition, the reason for male dominances in RSV infection at young ages was also inconclusive. Therefore, gender analysis in recurrent wheezing children with RSV infection can shed light on asthma pathogenesis. We studied the clinical features and the laboratory data of RSV infections in children who had recurrent wheezing histories. The subjects with RSV infection consisted of 98 boys and 58 girls. The children under 4 yr of age were 123 (78.8%) in number. Children with pneumonia were 78 and those with febrile episode were 119. Children above 1 yr of age were highly sensitized with mite antigen (75/96, 78.1%). The clinical symptoms and signs differed according to their ages. Children in each age group behaved differently in their immune reaction to RSV. Above all, 3-yr-old children deteriorated clinically during acute RSV infection, accompanied by transient elevated C-reactive protein (CRP) and suppressed blood eosinophil counts. Clinical features differed in several points between boys and girls. In general, the white blood cell count and the CRP levels were higher in girls in every age group. Blood eosinophil counts at the acute illness were significantly higher in boys than girls aged 2 and 3< yr. Age and gender comparison in already sensitized children might suggest a clue to asthma pathogenesis.

Airway inflammation in asymptomatic children with episodic wheeze

Airway pathologies have been comprehensively researched in adult asthma, but in children, the extent of airway inflammation associated with episodic wheeze, often diagnosed as asthma, has not been fully characterized. It is not clear whether persistent airway inflammation is present in the absence of wheezing symptoms, and there is controversy regarding the role of age and atopy. This study assessed cellular and cytokine markers of airway inflammation in asymptomatic children with a history of episodic wheeze. Children with a history of episodic wheeze and cough (study group) and nonasthmatic patients requiring elective surgery (control group) were recruited. All subjects in the study group had a history of significant episodic wheezing (>2 episodes per year), and used only as-needed beta-agonist treatment. Bronchoalveolar lavage (BAL) was obtained using bronchoscopic lavage (study group) and nonbronchoscopic lavage (control group). Differential cell counts of BAL and flow cytometry were performed to identify T-lymphocyte phenotypes, and intracellular cytokine profiles were measured after phorbol-12-myristate 13-acetate (PMA) stimulation of BAL fluid T-cells. Twenty-one children with a history of 2-12 episodes of wheeze per year and 21 nonasthmatic subjects without respiratory symptoms were recruited. Study and control subjects were matched for age (median age, 5 years) and demographic characteristics. Study subjects had higher IgE levels, but their measurements were still within normal range. No significant differences in BAL differential cell counts were noted, and in both groups, the majority of T-cells were CD3+ CD8+, with a median CD4:CD8 ratio of 0.6. There was no significant difference in T-cell expression of the activation markers HLA-DR and CD25 (IL-2 receptor), or in PMA-induced production of the intracellular cytokines IFN-gamma, IL-2, IL-4, IL-5, and IL-10. The results of this study suggest that significant T-cell-driven airway inflammation is absent in mild or nonatopic, asymptomatic children of this age group who have episodic wheeze. Our findings support asthma management guidelines that do not recommend long-term treatment of this group of patients with anti-inflammatory medications.

Gender analysis in acute bronchiolitis due to respiratory syncytial virus

It is reasonable to compare immune reactions between boys and girls because many infections in the early stages are predominant in males. A relationship between immunomodulatory effects of sex hormone surge in boys at early months and infectious diseases is still unclear. We compared clinical features between boys and girls who suffered from wheezing that was initially triggered by acute respiratory syncytial virus (RSV) bronchiolitis. For systemic immune response evaluation, white blood cell (WBC) count, blood eosinophil count, and serum C-reactive protein (CRP) were measured. For local inflammation evaluation, scores for eosinophils and neutrophils in sputum were evaluated microscopically. Patients consisted of 90 boys and 51 girls. Most children were under 6 months of age. WBC counts and serum CRP levels were significantly increased in girls compared with boys. Blood eosinophilia at the acute stage was rarely observed in children after 6 months of age. For local response evaluation, sputum specimens obtained from 42 boys and 29 girls were microscopically examined. Sputum eosinophil score of 2+ and more was observed in boys (6/42) exclusively. In contrast, sputum neutrophilia was commonly observed in boys and girls. From a follow-up study, we confirmed that 28 children with RSV bronchiolitis showed wheezing episodes afterwards. However, their blood and sputum eosinophilia during RSV bronchiolitis did not reflect their subsequent wheezing. We speculated that gender-specific responses to RSV infection might account for male susceptibility. Differences in RSV pathogenicity between boys and girls should be further investigated in terms of asthma progression.

Bronchoalveolar lavage eosinophil cationic protein and interleukin-8 levels in acute asthma and acute bronchiolitis

OBJECTIVE

In this study, we measured the levels of eosinophil cationic protein (ECP) and interleukin (IL)-8 in bronchoalveolar lavage (BAL) fluid from patients with acute asthma and acute bronchiolitis, to determine any similarities or dissimilarities in the profiles of these biochemical markers in the two diseases.

METHODS

BAL fluids were obtained from children with acute asthma (n=16), infants with acute bronchiolitis caused by respiratory syncytial virus (n=18), and control subjects (n=14). Children with asthma were selected to be free of viral infection. BAL cell counts and differentials were determined, and ECP and IL-8 levels were measured by radioimmunoassay and ELISA, respectively.

RESULTS

ECP levels in BAL fluids were significantly higher in the asthma group than in the bronchiolitis (P<0.01) or control (P<0.0001) groups. However, IL-8 levels were significantly higher in the bronchiolitis group than in the asthma (P<0.01) or control (P<0.001) groups. IL-8 levels in the asthma group and ECP levels in the bronchiolitis group were similar to those of the control group.

CONCLUSION

This difference in profiles of ECP and IL-8 in acute asthma and acute bronchiolitis, together with a different inflammatory cell pattern, suggests that the nature of the inflammatory process within the lower respiratory tract may be distinctive in these two diseases.

The influence of intravenous hydrocortisone on cytokine levels in children with asthma

Nocturnal airway obstruction occurs frequently in childhood asthma and results from increased airway inflammation. Lymphocytes are believed to be key effector cells of airway wall inflammation, releasing pro-inflammatory mediators and cytokines. A previous study showed that hydrocortisone infusion, an effective anti-inflammatory treatment, improves nocturnal and daytime FEV(1) values. This study in 16 children with moderate asthma was designed to assess whether there exists day and night differences in IL-4, IL-5, IL-8, and IFN-gamma production of concanavaline A stimulated peripheral blood mononuclear cells. Furthermore, we investigated whether substitution of low serum cortisol levels with intravenous hydrocortisone would affect those parameters. Saline (as a placebo) or hydrocortisone (30 microg/m(2) body surface area/24 h) was intravenously administered in a randomized, double blind, cross-over design. Measurements under saline or hydrocortisone infusions were separated by 1 wk. At 04:00 and 16:00 hours 10 ml blood was taken for determination of peripheral blood mononuclear cell isolation and stimulation, and an eosinophil count. Hydrocortisone infusion significantly reduced the nocturnal fall in FEV(1). Median values of IFNgamma, IL-4, IL-5, and IL-8 produced by peripheral blood mononuclear cells did not significantly differ at 04:00 and 16:00 hours, both with saline and hydrocortisone infusion. Our results suggest that FEV(1) improvement is not due to suppression of circulating peripheral blood mononuclear cell activation. We hypothesize that it is rather due to its effect on local lung tissue epithelial and/or fibroblasts thereby reducing airway inflammation and vascular leakage.

Markers of eosinophilic inflammation and tissue re-modelling in children before clinically diagnosed bronchial asthma

Chronic inflammatory changes in the bronchial mucosa have been well documented in patients with established asthma. Much less is known of the changes, which occur in the airways of children early in the evolution of their disease with most of the information based on indirect markers of inflammation only. We evaluated markers of inflammation and tissue re-modelling in bronchial biopsies from children with early respiratory symptoms before a clear clinical diagnosis of bronchial asthma could be made. We examined bronchial biopsies performed in 27 children between the ages of 1.2 and 11.7 yr who were bronchoscoped for a clinical indication because of recurrent or chronic respiratory symptoms. The patients were re-evaluated 22-80 months after the original bronchoscopy to determine whether or not they had subsequently developed bronchial asthma. There were more eosinophils in the bronchial mucosa (129.4 vs. 19.1 cells/mm2 of lamina propria, p <0.001) and the thickness of the subepithelial lamina reticularis was greater (4.65 vs. 3.72 microm, p=0.044) in children with bronchial asthma diagnosed at follow-up, compared with the children who did not progress to asthma. Eosinophilic inflammation and airway re-modelling occur early in the natural history of bronchial asthma and are present even before asthma would be diagnosed based on clinical symptoms. Recognition of these changes and their significance for clinical disease should emphasize the need for timely detection and diagnosis of asthma in children to facilitate the early introduction of anti-asthma therapy.

Difficult asthma in the pre-school child

The most important aspect of dealing with a pre-school child suspected of having difficult asthma, is to ensure that the diagnosis is correct, in order to avoid the inappropriate use of therapies such as inhaled corticosteroids. After exclusion of other diagnoses, if a pre-school child is thought to have asthma, difficult or otherwise, the corollary is, what sort of asthma? Is it a syndrome with airway inflammation susceptible to treatment, or one in which there is no inflammation and time alone will result in resolution of symptoms? Probably the most common mistake in this age group is to fail to recognise the latter and institute ever more aggressive and useless therapies. An approach to excluding other diagnoses, appropriate investigations to elicit the presence of airway inflammation and suggestions for subsequent management have been detailed in this review.

Childhood asthma: exhaled markers of airway inflammation, asthma control score, and lung function tests

Exhaled markers of airway inflammation become increasingly important in the management of childhood asthma. The aims of the present study are: 1) to compare exhaled markers of inflammation (nitric oxide, carbon monoxide, and acidity of breath condensate) with conventional asthma measures (lung function tests and asthma control score) in childhood asthma; and 2) to investigate the detectability of albumin, CRP, IL-6, IL-8, TNF-alpha, sICAM-1, and sTNF-R75 in the exhaled breath condensate (EBC) of asthmatic children. Thirty-two children with mild to moderate persistent asthma and healthy controls aged 6-12 years were studied. We measured exhaled NO and CO, and subsequently EBC was collected. Inflammatory mediators in EBC were measured using an enzyme-linked immunosorbent assay. Respiratory symptoms and asthma control were assessed using the asthma control questionnaire (ACQ) of Juniper et al. (Eur Respir J 1999;14:902-907). Exhaled NO showed a significant correlation with exhaled CO (r = 0.59, P < 0.05) and FEV1 (r = -0.59, P < 0.05), but not with ACQ score (r = 0.48, P = 0.06). Exhaled CO was correlated with prebronchodilator FEV1 (r = -0.45, P < 0.05), but not with asthma control (r = 0.18, P = 0.35). Acidity of EBC was significantly lower in asthmatic children than in healthy controls (P < 0.05), but did not correlate with any of the conventional asthma measures. We were not able to demonstrate the presence of CRP, IL-6, IL-8, TNF-alpha, sICAM-1, and sTNF-R75 in EBC. Albumin was found in two EBC samples of asthmatic children. We conclude that exhaled NO had a better correlation with lung function parameters and asthma control than exhaled CO and acidity of EBC, in mild to moderate persistent childhood asthma. However, exhaled NO, CO, and deaerated pH of EBC did not differ between asthmatic children and controls, possibly because of a too homogeneous and well-controlled study population. To further evaluate the clinical utility of exhaled markers in monitoring childhood asthma, more studies are required on a wider range of asthma severity, and preferably with repeated measurements of markers and of asthma control.

Exhaled breath condensate eicosanoids and sputum eosinophils in asthmatic children: a pilot study

Cysteinyl leukotrienes (cys-LTs), LTB4 and 8-isoprostane are increased in the exhaled breath condensate (EBC) from asthmatic patients. The aim of this study was to investigate whether the measurement of cys-LTs, LTB4 and 8-isoprostane in EBC can reflect the level of airway inflammation assessed by induced sputum in asthmatic children sensitized to house dust mite (HDM) during natural avoidance of HDM allergens. Twelve children were evaluated at the time of admission (T0) and after 3 months of stay (T1) at the Istituto Pio XII (Misurina, Italian Dolomites 1756 m). Sputum eosinophil percentage and measurement of cys-LTs, LTB4 and 8-isoprostanes in the breath condensate at T0 and T1 were evaluated. Eosinophil percentage in induced sputum was 8.5 +/- 1.1% at T0 and 3.5 +/- 0.4% at T1 (p = 0.011). Neutrophil percentage in sputum was 1.1 +/- 0.5% at T0 and 1.5 +/- 1.0% at T1 (ns). Cys-LTs mean level was 14.24 +/- 4.53 pg/ml at T0 and 4.65 +/- 0.68 pg/ml at T1 (p = 0.0125). LTB4 level was 2.36 +/- 0.19 pg/ml at T0 and 2.41 +/- 0.23 pg/ml at T1 (ns). 8-Isoprostane level reduced from 17.47 +/- 3.18 pg/ml at T0 to 7.36 +/- 3.26 pg/ml at T1 (p = 0.003). This study show that exhaled cys-LTs and 8-isoprostane, as well as eosinophil percentage in induced sputum, are reduced after allergen avoidance in asthmatic children suggesting a potential application of EBC for the non-invasive evaluation of airway inflammation in asthma in allergic asthmatic children.

Clinical and biological heterogeneity in children with moderate asthma

To evaluate the relationship between inflammatory markers and severity of asthma in children, the amount of interleukin-8 (IL-8) and granulocyte/macrophage colony-stimulating factor (GM-CSF) released by peripheral blood mononuclear cells, exhaled nitric oxide (FE NO) levels, p65 nuclear factor-kappaB subunit, and phosphorylated IkBalpha expression by peripheral blood mononuclear cells were assessed in six control subjects, 12 steroid-naives subjects with intermittent asthma, and 17 children with moderate asthma. To investigate their predictive value, biomarker levels were correlated with the number of exacerbations during a 18-month follow-up period. We found that GM-CSF release was higher in moderate and intermittent asthmatics than in control subjects, whereas IL-8 release was higher in moderate than in intermittent asthmatics and control subjects. FE NO levels were similar among study groups. In moderate asthmatics, IL-8, GM-CSF, and FE NO significantly correlated with the exacerbation numbers. Moreover, p65 and phosphorylated IkBalpha levels were greater in moderate than in intermittent asthmatics and control subjects. According to GM-CSF, IL-8, and FE NO levels, two distinct subgroups of moderate asthmatics (low and high producers) were identified. High producers experienced more exacerbations than low producers. This study shows ongoing inflammation associated with biological and clinical heterogeneity in moderate asthmatics despite regular treatment and proposes that large prospective studies confirm the importance of biomarkers to assess inflammation and asthma control in children with asthma.

Stimulation of P2 purinergic receptors induces the release of eosinophil cationic protein and interleukin-8 from human eosinophils

1. Extracellular nucleotides are the focus of increasing attention for their role as extracellular mediators since they are released into the extracellular environment in a regulated manner and/or as a consequence of cell damage. 2. Here, we show that human eosinophils stimulated with different nucleotides release eosinophil cationic protein (ECP) and the chemokine interleukin 8 (IL-8), and that release of these two proteins has a different nucleotide requirement. 3. Release of ECP was triggered in a dose-dependent manner by ATP, UTP and UDP, but not by 2'-&3'-o-(4-benzoyl-benzoyl)adenosine 5'-triphosphate (BzATP), ADP and alpha,beta-methylene adenosine 5' triphosphate (alpha,beta-meATP). Release of IL-8 was triggered by UDP, ATP, alpha,beta-meATP and BzATP, but not by UTP or ADP. Pretreatment with pertussis toxin abrogated nucleotide-stimulated ECP but not IL-8 release. 4. Release of IL-8 stimulated by BzATP was fully blocked by the P2X(7) blocker KN-62, while release triggered by ATP was only partially inhibited. IL-8 secretion due to UDP was fully insensitive to KN-62 inhibition. 5. Priming of eosinophils with GM-CSF increased IL-8 secretion irrespectively of the nucleotide used as a stimulant. 6. It is concluded that extracellular nucleotides trigger secretion of ECP by stimulating a receptor of the P2Y subfamily (possibly P2Y(2)), while, on the contrary, nucleotide-stimulated secretion of IL-8 can be due to activation of both P2Y (P2Y(6)) and P2X (P2X(1) and P2X(7)) receptors.

Neutrophils in asthma pathophysiology

Although the role of eosinophils, mast cells, and T cells in asthma has long been recognized, several reports suggest that neutrophils may also be involved. In most studies of people with mild asthma, neutrophil numbers in the airways are not different from controls. However, in severe asthma, including asthma deaths, neutrophils are usually raised. Furthermore, most pediatric studies suggest that neutrophils are raised in some children, in particular in the young or infantile wheeze group. Measurements of inflammatory mediators in the airways of asthmatic subjects suggest that neutrophils are activated.

Interleukin-6, interleukin-8, interleukin-11, and interferon-gamma levels in nasopharyngeal aspirates from wheezing children with respiratory syncytial virus or influenza A virus infection

The differences between respiratory syncytial virus (RSV) and influenza A virus (IFAV) in the pathogenesis of wheezing in young children have not been clearly defined. The aim of this study was to assess the contributions of RSV vs IFAV in the pathogenesis of upper airway inflammation in wheezy young children. We compared interleukin (IL)-6, IL-8, IL-11, and interferon-gamma (IFN-gamma) levels in nasopharyngeal aspirates (NPA) from non-asthmatic children with respiratory virus infections (RSV in 17 children and IFAV in 13 children), asthmatic children with viral infections (RSV in nine children, IFAV in 10 children), and 22 unaffected healthy children (controls). Levels of IL-11 in NPA from asthmatic children were significantly higher than those from non-asthmatic children with RSV infection, and RSV infection enhanced the IL-11 production in NPA significantly compared to IFAV infection. Nasopharyngeal epithelium from children with RSV infection secreted more IL-6 than that of children with IFAV infection. There was little difference in the IL-8 and IFN-gamma levels between asthmatic and non-asthmatic children with RSV or IFAV infection. In conclusion, asthma enhanced IL-11 production in RSV infection rather than IFAV infection in early childhood. There was a trend towards greater IL-6 production in RSV infection compared with IFAV infection.

15-deoxy-Delta 12,14-PGJ2 induces IL-8 production in human T cells by a mitogen-activated protein kinase pathway

Mast cells, platelets, and some macrophages are abundant sources of PGD(2) and its active metabolite 15-deoxy-Delta(12,14)-PGJ(2) (15-d-PGJ(2)). The lipid mediator 15-d-PGJ(2) regulates numerous processes, including adipogenesis, apoptosis, and inflammation. The 15-d-PGJ(2) has been shown to both inhibit as well as induce the production of inflammatory mediators such as TNF-alpha, IL-1beta, and cyclooxygenase, mostly occurring via a nuclear receptor called peroxisome proliferator-activated receptor-gamma (PPAR-gamma). Data concerning the effects of 15-d-PGJ(2) on human T cells and immune regulation are sparse. IL-8, a cytokine with both chemotactic and angiogenic effects, is produced by T lymphocytes following activation. Whether 15-d-PGJ(2) can regulate the production of IL-8 in T cells in unknown. Interestingly, 15-d-PGJ(2) treatment of unstimulated T cells induces cell death. In contrast, in activated human T lymphocytes, 15-d-PGJ(2) does not kill them, but induces the synthesis of IL-8. In this study, we report that 15-d-PGJ(2) induced a significant increase in both IL-8 mRNA and protein from activated human T lymphocytes. The induction of IL-8 by 15-d-PGJ(2) did not occur through the nuclear receptor PPAR-gamma, as synthetic PPAR-gamma agonists did not mimic the IL-8-inducing effects of 15-d-PGJ(2). The mechanism of IL-8 induction was through a mitogen-activated protein kinase and NF-kappaB pathway, as inhibitors of both systems abrogated IL-8 protein induction. Therefore, 15-d-PGJ(2) can act as a potent proinflammatory mediator in activated T cells by inducing the production of IL-8. These findings show the complexity with which 15-d-PGJ(2) regulates T cells by possessing both pro- and anti-inflammatory properties depending on the activation state of the cell. The implications of this research also include that caution is warranted in assigning a solely anti-inflammatory role for 15-d-PGJ(2).

A double-blinded, randomized, placebo-controlled trial of cetirizine in preventing the onset of asthma in children with atopic dermatitis: 18 months' treatment and 18 months' posttreatment follow-up

BACKGROUND

Because asthma is not a curable condition, the development of strategies for prevention of the disease has a high priority. Atopic dermatitis is a common precursor to the development of asthma, and 2 studies have suggested that the use of an H(1) receptor antagonist might reduce the development of asthma while the treatment is being administered, at least in subgroups with evidence of high IgE levels. However, no trial to date has conducted follow-up after the initial treatment has been stopped to establish whether the intervention has merely suppressed symptoms or truly prevented disease.

OBJECTIVE

We sought to establish whether the use of cetirizine compared with placebo for 18 months in infants with atopic dermatitis suppressed or truly delayed the onset of asthma, even after cessation of therapy.

METHODS

The Early Treatment of the Atopic Child study was a double-blinded, parallel-group, randomized trial of 0.25 mg/kg body weight cetirizine administered twice daily compared with placebo given to infants between 1 and 2 years of age with atopic dermatitis. After 18 months of treatment, follow-up continued for a further 18 months. This article reports the outcome over the full 3 years of follow-up and relates the outcomes to the allergic status on the basis of IgE antibody measurements at recruitment.

RESULTS

Although there was no difference in cumulative prevalence of asthma between active and placebo treatment in the intention-to-treat population (P = .7), those infants with evidence of sensitivity to house dust mite, grass pollen, or both who were treated with cetirizine were significantly less likely to have asthma compared with those treated with placebo over the 18 months of treatment (P = .005 and .002, respectively), and this effect was sustained for the grass pollen-sensitized infants over the full 36 months (P = .008). In the house dust mite-sensitized group there was a gradual narrowing of the difference between active and placebo treatment in terms of cumulative prevalence of asthma at the end of 36 months but no evidence of a rebound immediately after the treatment stopped (P = .04). In the placebo population there was a significantly higher risk of development of asthma in those sensitized at baseline to egg (relative risk, 1.4 [95% CI, 1.1-1.7]), house dust mite (relative risk, 1.6 [95% CI, 1.3-1.9]), grass pollen (relative risk, 1.7 [95% CI, 1.4-2.1]), or cat (relative risk, 1.5 [95% CI, 1.2-1.9]). Early and persistent sensitization conferred a higher risk than transient or later sensitization.

CONCLUSIONS

Cetirizine compared with placebo truly delays or, in some cases, prevents the development of asthma in a subgroup of infants with atopic dermatitis sensitized to grass pollen and, to a lesser extent, house dust mite. Further studies are required focusing specifically on sensitized groups to substantiate this finding. The study also highlights risk factors for asthma in infants with atopic dermatitis and indicates that early and persistent aeroallergen sensitization confers a higher risk than later development of sensitivity.