Chemotherapy for malignancy induces a remission in asthma symptoms and airway inflammation but not airway hyperresponsiveness

Inflammation with infiltrations of eosinophils and mast cells into the walls of airways is considered to increase airway hyperresponsiveness (AHR), which in turn characterizes asthma. We present a child with AHR in whom the clinical course of asthma was related to eosinophilic bronchitis. Our patient was admitted at age 6 months with bronchiolitis and at age 4 years with asthma. Inhaled corticosteroids were begun at age 7 years. At age 8 he developed a meningeal sarcoma. While on chemotherapy, his asthma symptoms resolved and he no longer required prophylactic asthma treatment. After 14 months off all chemotherapy, he again had mild episodic asthma. While receiving chemotherapy for malignancy, he had an admission with a coagulase negative staphylococcal bacteremia. During sputum induction with 4.5% saline, he developed cough, wheeze, and a 20% reduction in peak expiratory flow (220 to 180 L/min) that reversed after treatment with salbutamol. The sputum cell count was 1.7 × 10⁶/ml with 1.1 × 10⁶ being neutrophils. Two weeks later and prior to the induction of the second sputum, a 21% increase in FEV₁ was recorded after bronchodilator inhalation (82% to 99% of predicted). The second sputum contained 2.7 × 10⁶/ml cells with 1.6 × 10⁶/ml neutrophils. Neither eosinophils nor mast cells were identified in the sputum. A third sputum obtained 14 months after the cessation of chemotherapy showed a sputum cell count of 16 × 10⁶/ml, with 11.6 × 10⁶ neutrophils and 0.4 × 10⁶ eosinophils; no mast cells were detected. A reversible 15% reduction in FEV₁ was detected on hypertonic saline challenge testing. This boy had persistent airway hyperreactivity and reversible airways obstruction on three occasions during and following chemotherapy. When he developed asthma symptoms, his sputum contained neutrophils and eosinophils; while on chemotherapy his sputum did not contain eosinophils and he was symptom-free and off all asthma therapy. One can speculate that chemotherapy for malignancy can induce a remission in asthma symptoms but not AHR, and remission in symptoms is associated with a lack of eosinophilic or mast cell infiltrates in the sputum. Pediatr Pulmonol. 1998; 25:74–77. © 1998 Wiley-Liss, Inc.     

Natural porcine surfactant augments airway inflammation after allergen challenge in patients with asthma

There is increasing evidence for a role of pulmonary surfactant in asthma and allergic inflammation. In murine asthma models, recent studies have demonstrated that surfactant components downregulate the allergic inflammation. Therefore, we tested the hypothesis that in individuals with mild asthma, a natural porcine surfactant preparation (Curosurf) given before segmental allergen challenge can reduce the allergic airway inflammation. Ten patients with asthma and five healthy control subjects were treated in two segments with either Curosurf or vehicle followed by local allergen challenge. Six additional patients with asthma received Curosurf before allergen challenge in one segment as above, but the second segment was instilled with Curosurf without allergen challenge. Unexpectedly, surfactant treatment augmented the eosinophilic inflammation 24 hours after allergen challenge. A direct chemotactic effect of Curosurf was excluded. However, levels of eotaxin and interleukin-5 were increased in bronchoalveolar lavage after Curosurf treatment, whereas IFN-gamma-levels and numbers of IFN-gamma(+) T cells were decreased. Curosurf had no influence on spreading and retention of allergen determined by allergen uptake in mice. These findings demonstrate that treatment with a natural porcine surfactant results in an augmentation of the eosinophilic inflammation after allergen challenge that is more likely due to immunomodulatory effects than to biophysical properties of the surfactant.     

Anti-interleukin 5 but not anti-IgE prevents airway inflammation and airway hyperresponsiveness.

The role of IL-5 and allergen-specific IgE in the development of eosinophilic airway inflammation and airway hyperresponsiveness (AHR) was investigated in a murine model. BALB/c mice were sensitized to ovalbumin (OVA) by intraperitoneal injection on Days 1 and 14, followed by airway challenge with OVA on Days 28 and 29. Anti-IL-5 (TRFK-5) or anti-IgE (antibody 1-5) was administered before each airway challenge. Sensitized and challenged mice developed increased OVA-specific IgE serum levels, Th2 cytokine production by peribronchial lymph node (PBLN) cells, increased numbers of eosinophils (predominantly located in the peribronchial regions of the lungs), and increased airway responsiveness to methacholine (MCh). Anti-IgE treatment significantly decreased serum anti-OVA IgE levels and prevented the development of anaphylaxis but failed to affect T cell function, eosinophil airway infiltration, and AHR in sensitized and challenged mice. In contrast, treatment with anti-IL-5 antibody did not affect B cell (Ig serum levels), T cell (cytokine production), or mast cell function (immediate cutaneous reactivity) but completely inhibited development of eosinophilic lung inflammation and AHR. These data identify IL-5-mediated eosinophilia as a major target for development of AHR in this model, with little effect resulting from neutralization of IgE.     

Inhibition of phosphodiesterase 4 attenuates airway hyperresponsiveness and airway inflammation in a model of secondary allergen challenge

We compared for the first time the therapeutic potential of a specific phosphodiesterase 4 (PDE4) inhibitor, rolipram, with anti-VLA-4 and anti-IL-5 in a model of secondary allergen exposure of previously sensitized and challenged mice. To address these issues, mice were sensitized and challenged with ovalbumin (OVA) (primary challenge). Six weeks later, sensitized/challenged mice were reexposed to OVA (secondary challenge) and airway response (resistance [RL] and dynamic compliance [Cdyn]) to inhaled methacholine was monitored. After secondary OVA challenge, RL significantly increased as did the number of lung inflammatory cells and IL-4 and IL-5 production in bronchoalveolar lavage fluid (BALF). Administration of rolipram, in a dose-dependent manner, significantly prevented both changes in RL and Cdyn, as well as eosinophil, lymphocyte, and neutrophil accumulation in the BALF; IL-4 and IL-5 levels in BALF were also significantly reduced. In contrast, treatment with anti-VLA-4 and anti-IL-5 only prevented changes in RL and eosinophil numbers and IL-5 production in BALF. Further, goblet cell hyperplasia was suppressed only by treatment with rolipram. None of the treatments affected OVA-specific antibody levels. These studies confirm that IL-5 dependent eosinophilic inflammation plays an essential role in the development of certain aspects of airway function after rechallenge of sensitized mice and that lymphocytes and neutrophils are also important in the development of altered airway function. The use of agents that inhibit PDE4 may have an important role in the treatment of asthma in previously sensitized mice.     

IRAK-M knockout promotes allergic airway inflammation,but not airway hyperresponsiveness,in house dust mite-induced experimental asthma model

BackgroundIL-1 receptor associated-kinase (IRAK)-M, expressed by airway epithelium and macrophages, was shown to regulate acute and chronic airway inflammation exhibiting a biphasic response in an OVA-based animal model. House dust mite (HDM) is a common real-life aeroallergen highly relevant to asthma pathogenesis. The role of IRAK-M in HDM-induced asthma remains unknown. This study was aimed to investigate the effect of IRAK-M on allergic airway inflammation induced by HDM using IRAK-M knockout (KO) mice and the potential underlying mechanisms.MethodsIRAK-M KO and wild-type (WT) mice were sensitized and challenged with HDM. The differences in airway inflammation were evaluated 24 hours after the last challenge between the two genotypes of mice using a number of cellular and molecular biological techniques. In vitro mechanistic investigation was also involved.ResultsLung expression of IRAK-M was significantly upregulated by HDM in the WT mice. Compared with the WT controls, HDM-treated IRAK-M KO mice showed exacerbated infiltration of inflammatory cells, particularly Th2 cells, in the airways and mucus overproduction, higher epithelial mediators IL-25, IL-33 and TSLP and Th2 cytokines in bronchoalveolar lavage (BAL) fluid. Lung IRAK-M KO macrophages expressed higher percentage of costimulatory molecules OX40L and CD 80 and exhibited enhanced antigen uptake. However, IRAK-M KO didn’t impact the airway hyperreactivity (AHR) indirectly induced by HDM.ConclusionsThe findings indicate that IRAK-M protects allergic airway inflammation, not AHR, by modifying activation and antigen uptake of lung macrophages following HDM stimulation. Optimal regulation of IRAK-M might indicate an intriguing therapeutic avenue for allergic airway inflammation.     

Allergic bronchial asthma: airway inflammation and hyperresponsiveness

The international consensus report on diagnosis and treatment of asthma was published in 1992 (Clin Exp Allergy 22: 1-72). According to the report, asthma is a chronic inflammatory disorder of the airways in which many cells play a role, including mast cells and eosinophils. Airway inflammation causes various symptoms of asthma which are usually associated with widespread but variable airflow obstruction and causes an associated increase in airway responsiveness to a variety of stimuli. The definition of asthma, provided in this report, is an epoch-making revision of the conventional recognition of asthma based on respiratory physiology and does not contradict the empirical knowledge that asthma responds well to steroid therapy. One reason, which led airway inflammation to be understood as a major factor in the pathophysiology of asthma is the technological advance and the widespread use of bronchoscopes. The use of bronchoscopy as a research tool has markedly improved the understanding of the pathology of asthma. It became also possible to link biopsy findings to autopsy findings in patients who died of asthma. However, it is relatively difficult to repeat a biopsy of the airway mucosal membranes in individual asthmatic patients. Here, animal models of asthma play a significant role. Findings from animal models can provide a clue for the development of new anti-asthmatic drugs. This paper will deal with the paradigm of allergic asthma and focus on recent topics of interleukin (IL)-4 and IL-5, which seem to play a central role in allergic asthma. The causative relationship between airway inflammation and hyperresponsiveness will be discussed.     

Roles of hyperresponsiveness and airway inflammation in bronchial asthma

Bronchial hyperresponsiveness is one important feature of bronchial asthma, and evidence has been accumulated that airway inflammation contributes to the specific airway response in asthmatic patients. Increase in airway responsiveness following viral infection, exposure to allergen, ozone or chemical sensitizers supports the evidence for a link between hyperresponsiveness and airway inflammation. However, as only some respiratory tract infections induce an increase in hyperresponsiveness, and patients with chronic bronchitis and cystic fibrosis have less airway hyperresponsiveness than asthmatics, airway inflammation is considered to be only one of many factors contributing to the hyperresponsiveness of asthmatic airways.     

Roflumilast, a phosphodiesterase 4 inhibitor, reduces airway hyperresponsiveness after allergen challenge

BACKGROUND: Roflumilast, an oral, once-daily phosphodiesterase 4 inhibitor, is currently in clinical development for the treatment of asthma. OBJECTIVES: This pilot study examined the effect of roflumilast on allergen-induced airway hyperresponsiveness (AHR) to histamine challenge and asthmatic response to allergen challenge. METHODS: In a randomized, double-blind, 2-period, crossover trial, 13 patients with mild allergic asthma [mean forced expiratory volume in 1 s (FEV(1)) % predicted = 86%] received a single dose of oral roflumilast 1,000 microg or placebo. Patients were administered roflumilast 60 min before allergen challenge, and asthmatic responses were assessed via change in FEV(1) 相似文献   

Clinical features and airway inflammation in mild asthma versus asymptomatic airway hyperresponsiveness

RATIONALE: We still do not know why some subjects with airway hyperresponsiveness (AHR) experience no respiratory symptoms. OBJECTIVES: Our aim was to compare pulmonary function, perception of bronchoconstriction, and airway inflammation in atopic subjects with mild recently diagnosed (<5 years, n=30) or longer-standing (5 years or more, n=30) symptomatic asthma in comparison with atopic subjects with asymptomatic AHR (n=27). METHODS: All subjects had measurements of expiratory flows, PC(20) methacholine, perception of breathlessness and induced sputum cell differential, eosinophil cationic protein and alpha(2)-macroglobulin levels. RESULTS: Compared with the other groups, PC(20) was significantly lower in longer-standing asthma and perception score for breathlessness at 20% fall in FEV(1) was lower in asymptomatic subjects. Markers of airway inflammation were similar in all groups. There were no significant correlations between sputum eosinophils, alpha(2)-macroglobulin and/or eosinophil cationic protein levels and FEV(1), FVC or PC(20) in either group. CONCLUSION: Subjects with mild asthma or asymptomatic AHR are similar in regard to induced sputum markers of airway inflammation. Although perception of bronchoconstriction was slightly lower in asymptomatic subjects, additional factors are probably involved to explain why they report no respiratory symptoms. Further studies are needed to determine why these last are asymptomatic.     

IL-10 is necessary for the expression of airway hyperresponsiveness but not pulmonary inflammation after allergic sensitization

Cytokines play an important role in modulating inflammatory responses and, as a result, airway tone. IL-10 is a regulatory cytokine that has been suggested for treatment of asthma because of its immunosuppressive and anti-inflammatory properties. In contrast to these suggestions, we demonstrate in a model of allergic sensitization that mice deficient in IL-10 (IL-10-/-) develop a pulmonary inflammatory response but fail to exhibit airway hyperresponsiveness in both in vitro and in vivo assessments of lung function. Reconstitution of these deficient mice with the IL-10 gene fully restores development of airway hyperresponsiveness comparable to control mice. These results identify an important role of IL-10, downstream of the inflammatory cascade, in regulating the tone of the airways after allergic sensitization and challenge.     

Markers of airway inflammation and airway hyperresponsiveness in patients with well-controlled asthma.

In steroid-naive asthmatics, airway hyperresponsiveness correlates with noninvasive markers of airway inflammation. Whether this is also true in steroid-treated asthmatics, is unknown. In 31 stable asthmatics (mean age 45.4 yrs, range 22-69; 17 females) taking a median dose of 1,000 microg inhaled corticosteroids (ICS) per day (range 100-3,600 microg x day(-1)), airway responsiveness to the "direct" agent histamine and to the "indirect" agent mannitol, lung function (forced expiratory volume in one second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF)), exhaled nitric oxide (eNO), and number of inflammatory cells in induced sputum as a percentage of total cell count were measured. Of the 31 subjects, 16 were hyperresponsive to mannitol and 11 to histamine. The dose-response ratio (DRR: % fall in FEV1/cumulative dose) to both challenge tests was correlated (r=0.59, p=0.0004). However, DRR for histamine and DRR for mannitol were not related to basic lung function, eNO, per cent sputum eosinophils and ICS dose. In addition, NO was not related to basic lung function and per cent sputum eosinophils. In clinically well-controlled asthmatics taking inhaled corticosteroids, there is no relationship between markers of airway inflammation (such as exhaled nitric oxide and sputum eosinophils) and airway responsiveness to either direct (histamine) or indirect (mannitol) challenge. Airway hyperresponsiveness in clinically well-controlled asthmatics appears to be independent of eosinophilic airway inflammation.     

Role of nitric oxide in airway inflammation and hyperresponsiveness in bronchial asthma

Nitric oxide (NO) is produced within the airways and has a variety of actions on the airway function. Nitric oxide is a potent bronchodilator, and NO released from airway epithelial cells and inhibitory nonadrenergic non-cholinergic nerve terminals may attenuate airway hyperresponsiveness. However, a large amount of NO produced by inducible NO synthase may facilitate airway inflammation, which then leads to airway hyperresponsiveness. Although the role of NO remains controversial, the measurement of exhaled NO may well be of value in the clinical management of asthma.     

Dose-dependent effects of inhaled mometasone furoate on airway function and inflammation after allergen inhalation challenge

Comparisons of the potency of different inhaled corticosteroids, delivery devices, and treatment regimens in the management of asthma can only be made when outcome measurements display a dose-dependent effect. These outcomes have been difficult to identify. In this study, we compared in a randomized, double-blind, crossover design, the effects of 6 d treatment with placebo and three doses (50, 100, and 400 microg, twice daily) of mometasone furoate delivered by dry powder inhaler (MF-DPI) on responses after allergen inhalation challenge. Twelve mild asthmatic subjects with dual responses after allergen inhalation were studied. Outcome measurements included early and late asthmatic responses, the change in methacholine airway responsiveness 24 h after challenge, and sputum eosinophilia measured 7 and 24 h after challenge. All three doses of MF-DPI demonstrated similar attenuation of early responses and allergen-induced airway hyperresponsiveness relative to placebo (p < 0.05). The late maximal %fall in FEV(1) after placebo treatment was 23.5% and was significantly reduced in a dose-dependent manner to 12.3%, 11.0%, and 5.9% for the 50-, 100-, and 400-microg twice-daily treatments (p = 0.007). The allergen-induced increase in sputum eosinophilia (x10(4) cells/ml) 24 h after challenge during placebo treatment was 60.2 and was significantly reduced to 24.0, 15.3, and 6.2 for the 50-, 100-, and 400-microg twice-daily treatments. MF-DPI is effective at attenuating allergen-induced early and late responses, airway hyperresponsiveness, and sputum eosinophilia, and dose-response effects exist for the attenuation of the late response.     

Mediator release after nasal airway challenge with allergen

An in vivo model of human allergic disease has been developed in which nasal challenge with antigen leads to physiologic changes, together with a release of increased amounts of inflammatory mediators into nasal secretions obtained by washing the nose with saline. In 105 experiments involving 35 subjects, only allergic subjects consistently demonstrated an increase in the concentrations of the mast cell mediator, histamine, and the putative mast cell mediators, TAME-esterase and PGD2. The release of each mediator was significantly (p less than 0.001) related to the physiologic change (sneezing). The release of each mediator also correlated significantly with the release of the other 2 mediators (p less than 0.001). This system, for the first time, clearly relates an in vivo symptom and mediator release and thus should provide an excellent tool for the further study of the allergic response and nasal pathophysiology.     

Migration to a western country increases asthma symptoms but not eosinophilic airway inflammation

The prevalence of asthma symptoms varies markedly throughout the world. However, the asthma mechanisms involved are not defined. Studying the effects of migration can help identify the reasons for this geographic variation. The aims of this study were to examine the prevalence of asthma symptoms, airway hyperresponsiveness (AHR), and induced sputum eosinophils in adolescents who migrate to Australia. The study was conducted in Sydney, Australia, where adolescent students completed a video symptom questionnaire, hypertonic saline challenge, sputum induction, and allergy skin testing. The 211 students had widely different cultural backgrounds, including Asian, South Pacific, Middle Eastern, European, and African countries. Among adolescents who were migrants to Australia, the prevalence of asthma symptoms was higher than that reported using a similar methodology in their country of origin. Asthma symptom prevalence was related to residence time in Australia. The prevalence of wheeze was 17.2% in recent arrivals, 20.5% in adolescents living in Australia for >2 years, and 36.3% in those living all their lifetime in Australia (P = 0.013). For every year of residence in Australia, there was an 11% increase in prevalence of current wheeze (odds ratio, 1.11; P = 0.02). This effect was not related to atopy, AHR, or eosinophilic airway inflammation. Sputum neutrophils were elevated in recent arrivals. In conclusion, adolescents who migrate to Australia report increased asthma symptoms, compared to their country of origin, and asthma symptoms are further increased for every additional year of residence in Australia. The development of wheeze after migration to Australia was independent of eosinophilic inflammation and consistent with noneosinophilic asthma mechanisms.     

Disruption of L-histidine decarboxylase reduces airway eosinophilia but not hyperresponsiveness

Histamine has a variety of airway actions and is considered to be an important mediator in asthma. This study examined the role of endogenous histamine in allergic airway eosinophil recruitment and hyperresponsiveness using L-histidine decarboxylase gene knockout mice. Histamine levels of the airways in L-histidine decarboxylase knockout mice were largely diminished compared with wild-type mice. Inhalation challenge with ovalbumin (OVA) in OVA-sensitized wild-type mice caused eosinophil accumulation in the lung as well as airway hyperresponsiveness to methacholine 3 days after the challenge. The eosinophil recruitment was significantly reduced in the knockout mice. In the bone marrow, the proliferation of eosinophils was enhanced after OVA challenge in the wild-type mice; however, the proliferation was significantly reduced in the knockout mice. The induction of P-selectin in the lung after OVA challenge was also inhibited in the knockout mice. In contrast, airway hyperresponsiveness was not suppressed in the knockout mice. These results suggest that endogenous histamine is involved in the accumulation of eosinophils into the airways after allergic challenge, possibly acting in the bone marrow and producing P-selectin in the airways. Furthermore, allergen-induced airway hyperresponsiveness appeared to occur independently of airway eosinophilia in our present model.     

Mechanisms of airway hyperresponsiveness in asthma

Abstract:   Airway hyperresponsiveness (AHR) is a fundamental abnormality in asthma. There are many potential factors contributing to the excessive airway response demonstrable on airway challenge. These range from abnormalities of airway smooth muscle, airway remodelling and airway inflammation to abnormalities in the neural control of airway calibre. None of these by themselves fully explains the abnormalities seen on the dose response curves of the asthmatic. In this review, the main mechanisms are described, together with recent evidence providing a pathway by which a number of these mechanisms may interact to cause AHR through abnormality in ventilation distribution and airway closure. There is now evidence for a close relationship between ventilation heterogeneity and AHR which could be exploited clinically.