Airway Inflammatory Cell Numbers Research Articles

Cannabinoid receptor 2 as a regulator of inflammation induced oleoylethanolamide in eosinophilic asthma

BackgroundOleoylethanolamide (OEA), an endogenously generated cannabinoid-like compound, has been reported to be increased in patients with severe asthma and aspirin-exacerbated respiratory disease. Recruitment of activated eosinophils in the airways is a hallmark of bronchial asthma. ObjectiveTo explore the direct contribution of cannabinoid receptor 2 (CB2), a cognate receptor of OEA, which induces of eosinophil activation in vitro and in vivo. MethodsWe investigated OEA signaling in the eosinophilic cell line dEol-1, in peripheral blood eosinophils from asthmatics. In order to confirm whether eosinophil activation by OEA is CB2 dependent or not, CB2 siRNA and the CB2 antagonist SR144528 were used. The numbers of airway inflammatory cells and the levels of cytokines were measured in bronchoalveolar lavage fluid, and airway hyper-responsiveness were examined in the BALB/c mice. ResultsCB2 expression was increased after OEA treatment in both peripheral blood eosinophils and dEol-1 cells. It was also elevated after OEA-induced recruitment of eosinophils to the lungs in vivo. However, SR144528 treatment reduced the activation of peripheral blood eosinophils from asthmatic patients. Furthermore, CB2 knockdown decreased the activation of dEol-1 cells and the levels of inflammatory and T2 cytokines. SR144528 treatment alleviated airway hyper-responsiveness and eosinophil recruitment to the lungs in vivo. ConclusionThese results suggest that CB2 may contribute to the pathogenesis of eosinophilic asthma. Our results provide a new insight into the molecular mechanism of signal transduction by OEA in eosinophilic asthma.

Changes in intestinal homeostasis and immunity in a cigarette smoke- and LPS-induced murine model for COPD: the lung-gut axis.

Chronic obstructive pulmonary disease (COPD) is often associated with intestinal comorbidities. In this study, changes in intestinal homeostasis and immunity in a cigarette smoke (CS)- and lipopolysaccharide (LPS)-induced COPD model were investigated. Mice were exposed to cigarette smoke or air for 72 days, except days 42, 52, and 62 on which the mice were treated with saline or LPS via intratracheal instillation. Cigarette smoke exposure increased the airway inflammatory cell numbers, mucus production, and different inflammatory mediators, including C-reactive protein (CRP) and keratinocyte-derived chemokine (KC), in bronchoalveolar lavage (BAL) fluid and serum. LPS did not further impact airway inflammatory cell numbers or mucus production but decreased inflammatory mediator levels in BAL fluid. T helper (Th) 1 cells were enhanced in the spleen after cigarette smoke exposure; however, in combination with LPS, cigarette exposure caused an increase in Th1 and Th2 cells. Histomorphological changes were observed in the proximal small intestine after cigarette smoke exposure, and addition of LPS had no effect. Cigarette smoke activated the intestinal immune network for IgA production in the distal small intestine that was associated with increased fecal sIgA levels and enlargement of Peyer’s patches. Cigarette smoke plus LPS decreased fecal sIgA levels and the size of Peyer’s patches. In conclusion, cigarette smoke with or without LPS affects intestinal health as observed by changes in intestinal histomorphology and immune network for IgA production. Elevated systemic mediators might play a role in the lung-gut cross talk. These findings contribute to a better understanding of intestinal disorders related to COPD.

Oleoylethanolamide induces eosinophilic airway inflammation in bronchial asthma

Asthma is a chronic eosinophilic inflammatory disease with an increasing prevalence worldwide. Endocannabinoids are known to have immunomodulatory biological effects. However, the contribution of oleoylethanolamide (OEA) to airway inflammation remains to be elucidated. To investigate the effect of OEA, the expression of proinflammatory cytokines was measured by RT-qPCR and ELISA in airway epithelial (A549) cells. The numbers of airway inflammatory cells and cytokine levels in bronchoalveolar lavage fluid, airway hyperresponsiveness, and type 2 innate lymphoid cells (ILC2s) were examined in BALB/c mice after 4 days of OEA treatment. Furthermore, eosinophil activation after OEA treatment was evaluated by measuring cellular CD69 levels in eosinophils from human peripheral eosinophils using flow cytometry. OEA induced type 2 inflammatory responses in vitro and in vivo. OEA increased the levels of proinflammatory cytokines, such as IL-6, IL-8, and IL-33, in A549 cells. In addition, it also induced eosinophilic inflammation, the production of IL-4, IL-5, IL-13, and IL-33 in bronchoalveolar lavage fluid, and airway hyperresponsiveness. OEA increased the numbers of IL-5- or IL-13-producing ILC2s in a mouse model. Finally, we confirmed that OEA increased CD69 expression (an eosinophil activation marker) on purified eosinophils from patients with asthma compared to those from healthy controls. OEA may play a role in the pathogenesis of asthma by activating ILC2s and eosinophils.

The significance of CD163-expressing macrophages in asthma

BackgroundCD163 is one of the scavenger receptors that are specifically expressed on macrophages and are well known to be upregulated by various inflammatory responses, including chronic obstructive pulmonary disease in airway diseases. ObjectiveTo evaluate the CD163 expression in the lungs of patients with fatal asthma and investigated whether CD163 contributes to the pathogenesis in asthma. MethodsThe CD163 expressions in the lungs of patients with fatal asthma (n = 9) and in those of nonasthma control subjects (n = 8) were tested by immunohistochemistry. In mouse models of asthma, airway hyperresponsiveness (AHR) and the numbers of airway inflammatory cells in the bronchoalveolar lavage fluid (BALF) were analyzed in the CD163-deficient mice and the control wild-type mice. ResultsThe numbers of CD163-positive macrophages in the lung tissues were significantly increased in the all 6 patients with fatal asthma than in the control subjects. In mouse models of asthma, AHR and the numbers of infiltrating leukocytes, such as eosinophils, lymphocytes, neutrophils, and macrophages, in the BALF were significantly decreased in the CD163-deficient mice when compared with control wild-type mice. The concentrations of interferon γ and interleukin 5 in the BALF were significantly decreased in the CD163-deficient mice when compared with those in the control wild-type mice. ConclusionCD163 may play important roles in airway inflammation and AHR in asthma.

Aerosolised Mesenchymal Stem Cells Expressing Angiopoietin-1 Enhances Airway Repair.

The aim of this study was to investigate the effects of MSCs and MSC-expressing ANGPT1 (MSC-pANGPT1) treatment via aerosolisation in alleviating the asthma-related airway inflammation in the rabbit model. Rabbits were sensitised and challenged with both intraperitoneal injection and inhalation of ovalbumin (Ova). MSCs and MSC-pANGPT1 cells were aerosolised into rabbit lungs using the MicroSprayer® Aerosolizer Model IA-1B 48h after injury. The post mortem was performed 3days following cell delivery. Histopathological assessments of the lung tissues and inflammatory response were quantitatively scored following treatments. Administration of aerosolised MSCs and MSC-pANGPT1 were significantly reduced inflammation of the airways (p < 0.001), as reflected by improved of structural changes such as thickness of the basement membrane, epithelium, mucosa and sub-mucosa regions. The airway inflammation score of both treatment groups revealed a significant reduction of inflammation and granulocyte infiltration at the peribronchiale and perivascular regions (p < 0.05). Administration of aerosolised MSCs alone was resulted in significant reduction in the levels of pro-inflammatory genes (IL-4 and TGF-β) while treatment with aerosolised MSC-pANGPT1 led to further reduction of various pro-inflammatory genes to the base-line values (IL4, TNF, MMP9 and TGF-β). Treatment with both aerosolised MSCs and MSC-pANGPT1 cells was also alleviated the number of airway inflammatory cells in the bronchoalveolar lavage (BAL) fluid and goblet cell hyperplasia. Our findings suggest that treatment with MSCs alone attenuated airway inflammation and structural changes of the airway. Treatment with MSC-pANGPT1 provided an additional effect in reducing the expression levels of various pro-inflammatory genes. Both of these treatment enhancing airway repair and therefore may provide a basis for the development of an innovative approach for the treatment and prevention of airway inflammatory diseases.

Effect of waterpipe tobacco smoking on airway inflammation in murine model of asthma

Objective: There has been an increase in the popularity of waterpipe tobacco smoking (WTS) worldwide, especially in the younger population, including asthma patients. In this study, we investigated the effects of waterpipe smoking on airway inflammation, cytokine levels and oxidative stress markers in an antigen-driven murine model of asthma.Materials and methods: Balb/c mice were divided into four groups; (1) control (received fresh air, ovalbumin sensitization and saline challenge), (2) WTS (received WTS, ovalbumin sensitization and saline challenge), (3) Ova S/C (received fresh air, ovalbumin sensitization and ovalbumin challenge) and (4) simultaneous WTS and Ova S/C (received WTS, ovalbumin sensitization and ovalbumin challenge). Airway inflammatory cells were evaluated in the broncho-alveolar lavage fluid. Cytokines [interleukin (IL)-13, 10 and 18] and oxidative stress markers [superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx)] were evaluated in the lung homogenates.Results: Chronic exposure to WTS significantly increased the number of airway inflammatory cells in mice, specifically: eosinophils, neutrophils, macrophages and lymphocytes. The level of IL-13 in the lungs was increased and the level of IL-10 was reduced (p < 0.05) by WTS.Chronic WTS potentiated the increase in inflammatory cells induced by Ova S/C (p < 0.05). The level of IL-13 in the lungs was increased by simultaneous WTS and Ova S/C (p < 0.05) while, levels of IL-10, IL-18, SOD, catalase and GPx in the lungs were not affected.Conclusions: Chronic WTS exposure induced airway inflammation in control mice and enhanced airway inflammation in murine model of asthma.

P2Y12 antagonist attenuates eosinophilic inflammation and airway hyperresponsiveness in a mouse model of asthma.

Leukotriene E4 (LTE4) that plays a key role in airway inflammation is expressed on platelets and eosinophils. We investigated whether blocking of the P2Y12 receptor can suppress eosinophilic inflammation in a mouse model of asthma because platelets and eosinophils share this receptor to be activated. BALB/c mice were sensitized by intraperitoneal injection of ovalbumin (OVA), followed by OVA nebulization. On each challenge day, clopidogrel, a P2Y12 antagonist was administered 30 min. before each challenge. Forty-eight hours after the last OVA challenge, mice were assessed for airway hyperresponsiveness (AHR), cell composition and cytokine levels, including chemokine ligand 5 (CCL5), in bronchoalveolar lavage (BAL) fluid. EOL cells were treated with LTE4, with or without clopidogrel treatment, and intracellular and extracellular eosinophil cationic protein (ECP) expressions were measured to find the inhibiting function of P2Y12 antagonist on eosinophilic activation. The levels of P2Y12 expression were increased markedly in the lung homogenates of OVA-sensitized and -challenged mice after platelet depletion. Administration of clopidogrel decreased AHR and the number of airway inflammatory cells, including eosinophils, in BAL fluid following OVA challenge. These results were associated with decreased levels of Th2 cytokines and CCL5. Histological examination showed that inflammatory cells as well as mucus-containing goblet cells were reduced in clopidogrel-administered mice compared to vehicle-treated mice. Clopidogrel inhibited extracellular ECP secretion after LTE4 stimulation in EOL-1 cells. Clopidogrel could prevent development of AHR and airway inflammation in a mouse model of asthma. P2Y12 can be a novel therapeutic target to the suppression of eosinophils in asthma.

Attenuation of airway inflammation by simvastatin and the implications for asthma treatment: is the jury still out?

Although some studies have explained the immunomodulatory effects of statins, the exact mechanisms and the therapeutic significance of these molecules remain to be elucidated. This study not only evaluated the therapeutic potential and inhibitory mechanism of simvastatin in an ovalbumin (OVA)-specific asthma model in mice but also sought to clarify the future directions indicated by previous studies through a thorough review of the literature. BALB/c mice were sensitized to OVA and then administered three OVA challenges. On each challenge day, 40 mg kg−1 simvastatin was injected before the challenge. The airway responsiveness, inflammatory cell composition, and cytokine levels in bronchoalveolar lavage (BAL) fluid were assessed after the final challenge, and the T cell composition and adhesion molecule expression in lung homogenates were determined. The administration of simvastatin decreased the airway responsiveness, the number of airway inflammatory cells, and the interleukin (IL)-4, IL-5 and IL-13 concentrations in BAL fluid compared with vehicle-treated mice (P<0.05). Histologically, the number of inflammatory cells and mucus-containing goblet cells in lung tissues also decreased in the simvastatin-treated mice. Flow cytometry showed that simvastatin treatment significantly reduced the percentage of pulmonary CD4+ cells and the CD4+/CD8+ T-cell ratio (P<0.05). Simvastatin treatment also decreased the expression of the vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 proteins, as measured in homogenized lung tissues (P<0.05) and human epithelial cells. The reduction in the T cell influx as a result of the decreased expression of cell adhesion molecules is one of the mechanisms by which simvastatin attenuates airway responsiveness and allergic inflammation. Rigorous review of the literature together with our findings suggested that simvastatin should be further developed as a potential therapeutic strategy for allergic asthma.

Persistence of systemic inflammation in COPD in spite of smoking cessation

Cigarette smoking, which exposes the lung to high concentrations of reactive oxygen species (ROS), is the major risk factor for chronic obstructive pulmonary disease (COPD) [1]. ROS are responsible for lipid peroxidation, protein oxidation, DNA alterations, and cell damage. Coupled with oxidant/antioxidant imbalance, these changes lead to lung inflammatory responses through multiple pathways, among which the activation of stress kinases (c-Jun activated kinase, extracellular signal-regulated kinase, p38 kinase) and redox-sensitive transcription factors, such as nuclear factor (NF)-kappaB and activator protein-1, resulting in the expression of kinase- and NF-κB-dependent proinflammatory cytokines and chemokines [2]. COPD is related to smoking habit in the majority of cases, and smoking cessation is the single most beneficial and effective way to reduce COPD morbidity, hospital admissions and disease progression [1]. However, persistent inflammation in the airways of COPD subjects may continue after smoking cessation, as shown by studies showing a similar number of airway inflammatory cells, including CD4+ and CD8+ lymphocytes, in the bronchial biopsies of both current smokers and ex-smokers with COPD [3], and by other studies analyzing the composition of induced sputum, which showed a persistent increase in the number of airway neutrophils and lymphocytes one year after smoking cessation [4]. A persistent overall burden of non invasive markers of oxidative stress has also been found in the airways after smoking cessation [5]. Also systemic markers of inflammation were found elevated in the serum of COPD patients [6,7]. Taken together, these studies indicate that, in COPD patients, ongoing inflammation is persistent in spite of smoking cessation: this phenomenon is considered one of the determinants of the progressive decline in lung function. This issue of Multidisciplinary Respiratory Medicine features an article by Serapinas et al. [8] on the presence of markers of systemic inflammation in a sample of 320 COPD patients according to their smoking status. The authors devoted their attention to the serum concentrations of the following set of oxidant markers: C-reactive protein (CRP), alpha-1 antitrypsin (AAT), tumor necrosis factor-α (TNF-α), and soluble tumor necrosis factor receptor (sTNFR)-1 and sTNFR-2. The markers were analyzed in relation to current smoking (n = 202) and ex-smoking (n = 61), as well never-smoker (n = 57) status. Mean (SD) forced expiratory volume in one second/forced vital capacity (FEV1/FVC) (%) was 54.8 (10.7), while mean (SD) pack/years in smokers and ex-smokers was 22.7 ± 12.9. The main result of the study was that AAT, CRP and sTNFR-1 concentrations were significantly increased in both smokers and ex-smokers as compared to never-smokers. This study adds to the number of reports showing the presence of systemic and airway inflammation in COPD patients, irrespective of whether they were current or ex-smokers. Although inflammation is also present as a consequence of smoking in the airways of asymptomatic smokers, a significant decrease of oxidant markers occurs after smoking cessation in these subjects [4]. It is not known why - at variance with what occurs in asymptomatic smokers - inflammation persists after quitting smoking in COPD patients [1]. One of the leading explanations is the altered regulation of inflammatory gene expression, even though epigenetic mechanisms are implicated too. In a recent study it has been shown that smoking per se modulates the expression of genes from all the inflammatory functional groups except for the matrix metalloproteinases group [10]. The inflammation related genes (except TNF-a) were found to be up-regulated, while genes from the growth factor/receptor group, adhesion molecules and vessel tone/maintenance factors were down-regulated in smokers. It is notable that all of these genes exhibited a similar profile in patients with moderate COPD, suggesting a crucial role of cigarette smoking in the genesis of these changes. However, one of the most significant changes associated with COPD was the increased expression of matrix metalloproteinases [10]. Although the COPD puzzle is still far from being solved, multidisciplinary research linking the different expertise of epidemiological, biological, translational and clinical nature is believed to be the best response to such a difficult task.

IL‐12 p80‐dependent macrophage recruitment primes the host for increased survival following a lethal respiratory viral infection

A protective immune response to a respiratory viral infection requires a series of coordinated cellular and molecular responses. We have previously demonstrated that increased expression of airway epithelial cell interleukin (IL)-12 p80, a macrophage chemoattractant, is associated with human respiratory viral infection and mediates post-viral mortality in the mouse. To better understand the role of IL-12 p80-dependent macrophage chemotaxis in mediating viral immunity, we generated a transgenic mouse strain utilizing a promoter to drive IL-12 p40 gene expression in the airway epithelium. This transgenic strain secreted biologically active IL-12 p80 in a lung-specific manner, and demonstrated a selective increase in the number of resident, unactivated airway macrophages at baseline. Following infection with a sublethal dose of mouse parainfluenza virus type 1 (Sendai virus), the transgenic mice demonstrated an earlier peak and decline in the number of airway inflammatory cells. The transgenic mice were resistant to a lethal dose of virus and this viral resistance was dependent on the increased number of airway macrophages at baseline as partial depletion prior to infection abrogated this phenotype. The survival advantage in the transgenic mice was independent of viral load but was associated with a more rapid decline in the number of airway inflammatory cells and concentrations of multiple chemokines including the CC chemokine ligand 2 (CCL2)/JE, CCL3/macrophage inflammatory protein (MIP)-1alpha, CCL4/MIP-1beta, and CCL5/RANTES. Collectively, these results suggest that IL-12 p80-driven increases in the number of resident airway macrophages prime the host for a protective immune response that can confer increased survival following a lethal respiratory viral infection.

Selective Inducible Nitric Oxide Synthase Inhibition Has No Effect on Allergen Challenge in Asthma

Exhaled breath nitric oxide (Fe(NO)) is increased in asthma. NO is produced predominantly by inducible nitric oxide synthase (iNOS). We evaluated the selective and potent iNOS inhibitor GW274150 in asthma. Twenty-eight steroid-naive patients with asthma participated in a double-blind, randomized, double-dummy, placebo-controlled, three-period cross-over study. Subjects received GW274150 (90 mg), montelukast (10 mg), or placebo once daily for 14 days. Fe(NO) was assessed predose on Days 1, 7, 10, and 14. Adenosine 5'-monophosphate (AMP) challenge was performed on Day 10, allergen challenge on Day 14 followed by methacholine challenge (MCh) 24 hours later, and then bronchoscopy. GW274150 reduced predose Fe(NO) by 73, 75, and 71% on Days 7, 10, and 14, respectively, compared with placebo. Montelukast did not reduce Fe(NO). GW274150 did not inhibit AMP reactivity whereas for montelukast there was a trend toward inhibition: the mean doubling dose difference versus placebo was 0.64 (95% confidence interval [95% CI], 0 to 1.28). GW274150 did not inhibit early (EAR) and late (LAR) asthmatic responses to allergen, or MCh reactivity, despite reduced Fe(NO) levels. Montelukast inhibited EAR and LAR FEV1; the mean difference versus placebo for minimal FEV1 was 0.37 L (95% CI, 0.19 to 0.55) and 0.18 L (95% CI, 0.04 to 0.32), respectively. MCh reactivity was inhibited by montelukast (mean doubling dose difference vs. placebo, 0.51; 95% CI, 0.02 to 1.01). GW271540 also had no effect on inflammatory cell numbers in bronchoalveolar lavage fluid after allergen challenge. Selective iNOS inhibition effectively reduces Fe(NO) but does not affect airway hyperreactivity or airway inflammatory cell numbers after allergen challenge in subjects with asthma. Clinical trial registered with www.clinicaltrials.gov (NCT00273013).

Role of intercellular adhesion molecule‐1 in a murine model of toluene diisocyanate‐induced asthma

Adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) are thought to contribute to the airway inflammation and airway hyper-responsiveness (AHR) of allergic asthma. Some differences from allergic asthma have been noted, including airway neutrophilia, and the involvement of ICAM-1 in toluene diisocyanate (TDI) asthma is currently unclear. We utilized mice lacking ICAM-1 expression (ICAM-1(-/-)) to investigate the role of ICAM-1 in airway inflammation and AHR in TDI-induced asthma. Male C57BL/6J mice (ICAM-1(+/+)) and ICAM-1(-/-) mice were intranasally sensitized to TDI solution or solvent alone. Airway inflammation, AHR and cytokine secretion were assessed 24 h after challenge by TDI or solvent. The production of antigen-specific IgG and IgE by TDI sensitized and non-sensitized mice was determined. TDI challenge to ICAM-1(+/+) mice induced an increase in airway inflammatory cell numbers, AHR and cytokine secretion of TNF-alpha, macrophage inflammatory protein-2 (MIP-2), IL-4, IL-5 and IFN-gamma into the bronchoalveolar lavage fluid. All these pathophysiological changes were reduced in ICAM-1(-/-) mice. Serum levels of TDI-specific IgG and IgE of ICAM-1(-/-) and ICAM-1(+/+) mice were comparable. These results suggest that ICAM-1 plays an essential role in airway inflammation and AHR in TDI-induced asthma.

Beyond Our Pages

Beyond Our Pages

IL-4 Receptor Signaling in Clara Cells Is Required for Allergen-Induced Mucus Production

Excessive mucus production is an important pathological feature of asthma. The Th2 cytokines IL-4 and IL-13 have both been implicated in allergen-induced mucus production, inflammation, and airway hyperreactivity. Both of these cytokines use receptors that contain the IL-4Ralpha subunit, and these receptors are expressed on many cell types in the lung. It has been difficult to determine whether allergen-induced mucus production is strictly dependent on direct effects of IL-4 and IL-13 on epithelial cells or whether other independent mechanisms exist. To address this question, we used a cell type-specific inducible gene-targeting strategy to selectively disrupt the IL-4Ralpha gene in Clara cells, an airway epithelial cell population that gives rise to mucus-producing goblet cells. Clara cell-specific IL-4Ralpha-deficient mice and control mice developed similar elevations in serum IgE levels, airway inflammatory cell numbers, Th2 cytokine production, and airway reactivity following OVA sensitization and challenge. However, compared with control mice, Clara cell-specific IL-4Ralpha-deficient mice were nearly completely protected from allergen-induced mucus production. Because only IL-13 and IL-4 are thought to signal via IL-4Ralpha, we conclude that direct effects of IL-4 and/or IL-13 on Clara cells are required for allergen-induced mucus production in the airway epithelium.

Gelatinase activities in the airways of premature infants and development of bronchopulmonary dysplasia.

Matrix-degrading metalloproteinases may play a role in the pathophysiology of bronchopulmonary dysplasia (BDP). We, therefore, evaluated correlations between gelatinase activities [metalloproteinase (MMP)-2 and MMP-9] or tissue inhibitor of metalloproteinase (TIMP)-1 levels present in the airways during the initial phase of hyaline membrane disease and the onset of BPD. Tracheal aspirates were obtained within 6 h of birth (day 0) from 64 intubated neonates with a gestational age < or =30 wk. Forty-five neonates were resampled on day 3 or 5. Total MMP-2 level measured by zymography fell with time, whereas total MMP-9 level and TIMP-1 levels, assayed by ELISA, increased; the MMP-9 increase correlated with the increase in airway inflammatory cell numbers. Among the parameters measured on day 0, 3, or 5, lower total MMP-2 level, lower birth weight, and higher fraction of inspired oxygen on day 0 were significantly and independently associated with the development of BPD. In conclusion, MMP-9 level and TIMP-1 levels increased after birth but are not linked to BPD outcome. In contrast, low MMP-2 level at birth is strongly associated with the development of BPD.

Early interventions in asthma with inhaled corticosteroids

We have earlier shown epithelial damage in the airway mucosa in patients with asthma. Later other structural changes have been recognized in asthma, such as deposition of collagen and tenascin in the subepithelial basement membrane and changes in the laminin subchain composition. These processes are modified by an inflammatory process in the airways. Both the United States National Institutes of Health and the British Thoracic Society guidelines on the management of asthma emphasize the need for early use of anti-inflammatory drugs. Many clinical studies that used airway biopsy specimens have shown a decrease in airway inflammatory cell numbers after inhaled corticosteroid therapy. However, there is very little information on the effects of asthma medication on the structural components of the airways. Both the synthesis and degradation of many extracellular matrix components may be affected by the disease process and the drugs resulting in altered remodeling and gene expression in the airways. Because there are only a few studies that try to identify early changes in asthma, it is not known whether the anti-inflammatory treatment of asthma proposed by the guidelines is started early enough. (J Allergy Clin Immunol 2000;105:S582-5.)

Bronchoalveolar lavage findings in patients with chronic nonproductive cough.

Mast cells and eosinophils may play a role in the pathophysiology of chronic cough in nonasthmatics. It is unknown, however, whether degranulation of these cells occurs in the airways of such patients. Thirty-five nonsmoking patients referred with a chronic nonproductive cough (mean cough duration 76.2 months) were evaluated using a comprehensive diagnostic protocol. Bronchoalveolar lavage (BAL) cell differentials and BAL histamine, tryptase and eosinophilic cationic protein (ECP) concentrations were determined. Ten nonsmoking healthy volunteers served as controls. Diagnostic subgroups were identified: eight postnasal drip syndrome (PNDS), seven cough variant asthma (CVA), seven gastro-esophageal reflux (GOR), seven dual aetiology and six idiopathic. Nonasthmatic coughers (NAC) were characterized as those patients without bronchial hyperresponsiveness on histamine challenge and whose cough had either responded to therapy for PNDS or GOR or failed to improve with antiasthma therapy. There was a significant increase in both eosinophil and mast cell numbers (p<0.05) and in histamine levels (p = 0.027) when NAC patients were compared with controls. Tryptase and ECP levels were elevated in 7 of 23 and 6 of 23 NAC patients, respectively. In conclusion, airway inflammatory cell numbers are not only increased but also activated, suggesting an important role for airways inflammation in the pathophysiology of chronic nonproductive cough.

Single oral dose of prednisone decreases leukotriene B 4 production by alveolar macrophages from patients with nocturnal asthma but not control subjects: Relationship to changes in cellular influx and FEV 1

Background: Nocturnal worsening of asthma is associated with an increase in numbers of airway inflammatory cells during the early morning. However, cell function during the night, with and without administration of steroids, has not been investigated. Objective: This study was designed to determine the effect of prednisone on pulmonary alveolar macrophage production of leukotriene B 2 and thromboxane B 2 at night and how it relates to changes in pulmonary function and cellular influx. Methods: Alveolar macrophages were obtained from patients with nocturnal asthma, patients with nonnocturnal asthma, and normal control subjects at 4:00 am by bronchoalveolar lavage after administration of placebo and prednisone. Cells were placed in limited cell culture, and eicosanoids were measured from baseline and stimulated cells. Results: Patients with nocturnal asthma had both a significantly greater fall in forced expiratory volume in 1 second (FEV 1) and a greater influx of neutrophils and eosinophils at 4:00 am than normal subjects after placebo treatment, whereas patients with nonnocturnal asthma had intermediary responses. There was no difference in baseline or stimulated LTB 4 production during placebo administration in the three groups. After prednisone treatment, there was an improvement in the nocturnal fall in FEV 1 and a significant decrease in the neutrophil influx in patients with nocturnal asthma compared with the other groups. These changes were accompanied by a significant decrease in the stimulated LTB 4 production in patients with nocturnal asthma compared with a small increase in both patients with nonnocturnal asthma and normal subjects. Thromboxane B 2 production did not change. The decrease in LTB 4 production was correlated with the fall in granulocytic cells and improvement in the nocturnal FEV 1. However, the two variables with the greatest combined influence on the improvement in FEV 1 were the decrease in stimulated LTB 4 production and the fall in neutrophil influx. Conclusions: We demonstrate for the first time that a single oral dose of prednisone decreases LTB 4 production from alveolar macrophages, obtained at night from patients with nocturnal asthma, during a time of known inflammation. Further, this decrease in stimulated production is associated with decreases in cellular influx and improvement in pulmonary function.

Changes in bronchoalveolar lavage inflammatory cells in asthmatic patients treated with high dose inhaled beclomethasone dipropionate

Using serial bronchoalveolar lavage (BAL), we have studied changes in the airway inflammatory cell populations in 20 asthmatic patients, before and after treatment with inhaled beclomethasone dipropionate (BDP), 2,000 micrograms daily in an uncontrolled study. There was a significant improvement in asthma severity, as measured by symptom score and airways responsiveness, and there were significant reductions in the total BAL eosinophil, epithelial cell and mast cell counts, with a significant increase in the percentage BAL lymphocyte count. No significant correlations were found between the changes in airway inflammatory cell numbers and the reduction in asthma severity. In contrast, the fall in ROS generation by the pulmonary macrophage and granulocyte populations was nonsignificant, but the improvement in airways responsiveness was positively correlated to the reduction in the unstimulated pulmonary macrophage activity. Although these data are uncontrolled, the results are compatible with previous studies in suggesting an effect of steroids on the eosinophil, mast cell and epithelial cell in asthmatic airways. They also highlight the probable importance of the luminal lymphocyte population and pulmonary macrophage activation within the asthmatic airway, the beneficial modulatory effect of inhaled BDP treatment upon them, and the relative steroid-resistance of pulmonary inflammatory cell activity.