Mast cell-associated alveolar inflammation in patients with atopic uncontrolled asthma (original) (raw)
Related papers
Key role for mast cells in nonatopic asthma
Journal of Allergy and Clinical Immunology, 2002
The mechanisms involved in non-atopic asthma are poorly defined. In particular, the importance of mast cells in the development of non-atopic asthma is not clear. In the mouse, pulmonary hypersensitivity reactions induced by skin sensitization with the low molecular weight compound dinitrofluorobenzene (DNFB) followed by an intra-airway application of the hapten have been featured as a model for non-atopic asthma. In the present study, we employed this model to examine the role of mast cells in the pathogenesis of non-atopic asthma. Firstly, the effect of DNFB sensitization and intra-airway challenge with dinitrobenzene sulphonic acid (DNS) on mast cell activation was monitored during the early phase of the response in BALB/c mice. Secondly, mast cell-deficient W/W v , Sl/Sl d mice and their respective normal (+/+) littermate mice and mast cell-reconstituted W/W v mice (BMMC→ W/W v ) were used. Early phase mast cell activation was found, which was maximal 30 min after DNS challenge in DNFB-sensitized BALB/c, +/+ mice, but not in mast cell-deficient mice. An acute bronchoconstriction and increase in vascular permeability accompanied the early phase mast cell activation. BALB/c, +/+ and BMMC→ W/W v mice sensitized with DNFB and DNS-challenged exhibited tracheal hyperreactivity 24 and 48 h after the challenge when compared to vehicle-treated mice. Mucosal exudation and infiltration of neutrophils in bronchoalveolar lavage fluid associated the late phase response.
Asthma is a chronic inflammatory disease of the lung and its pathophysiology is initiated by mast cell activation in response to the antigen binding to IgE receptor as well as by TH2 cell activation. Mast cells are well established effector cells in asthma where they exacerbate the inflammatory response, playing a key role in early phase, degranulating and increasing histamine. Human mast cells possess high affinity IgE receptors and are ubiquitous but predominantly localized in mucosal and connective tissue and are distributed along blood vessels. There are two types of mast cells: connective tissue mast cells (TC) and mucosal mast cells (T mast cells). TC mast cells contain more heparin, whereas T mast cells contain more chondroitin sulfate. In asthma, mast cell activation can trigger degranulation, releasing secretory granule complex and preformed mediators, such as histamine and proteases, along with the synthesis of leukotrines and prostaglandins, and induction of cytokines and chemokines. Leukotrine inhibitors and omalizumab, which inhibits IgE, both relieve the asthma exacerbation when administered to humans and permit to reduce the use of other drugs. The release of cytokines by mast cells, such as TNF-alpha, IL-1, IL-6 and IL-33, participate in the pathogenesis of asthma. Stress worsens asthma, and this effect is also mediated by mast cell activation through the release of cytokines. Administration of IL-33 in experimental animals provokes pathological effects in the mucosal tissues and augments antibody IgE and IgA in blood vessels. Here, we report the impact of mast cell biology in asthma pathogenesis.
The role of human mast cells in allergy and asthma
Bioengineered, 2022
Mast cells are tissue-inhabiting cells that play an important role in inflammatory diseases of the airway tract. Mast cells arise in the bone marrow as progenitor cells and complete their differentiation in tissues exposed to the external environment, such as the skin and respiratory tract, and are among the first to respond to bacterial and parasitic infections. Mast cells express a variety of receptors that enable them to respond to a wide range of stimulants, including the high-affinity FcεRI receptor. Upon initial contact with an antigen, mast cells are sensitized with IgE to recognize the allergen upon further contact. FcεRI-activated mast cells are known to release histamine and proteases that contribute to asthma symptoms. They release a variety of cytokines and lipid mediators that contribute to immune cell accumulation and tissue remodeling in asthma. Mast cell mediators trigger inflammation and also have a protective effect. This review aims to update the existing knowledge on the mediators released by human FcεRI-activated mast cells, and to unravel their pathological and protective roles in asthma and allergy. In addition, we highlight other diseases that arise from mast cell dysfunction, the therapeutic approaches used to address them, and fill the gaps in our current knowledge. Mast cell mediators not only trigger inflammation but may also have a protective effect. Given the differences between human and animal mast cells, this review focuses on the mediators released by human FcεRI-activated mast cells and the role they play in asthma and allergy.
Airway Tissue Mast Cells in Persistent Asthma
Chest, 2003
Study objectives: To determine if persistent airway tissue mast cells are associated with treatment failure when patients discontinue inhaled corticosteroids (ICS). Design: Double-blind, randomized, placebo-controlled trial. Setting: Multicenter, tertiary referral centers. Patients or participants: Forty-five subjects with asthma recruited from six medical centers in the United States. Interventions: The Asthma Clinical Research Network undertook a 28-week, randomized, multicenter, double-blind, placebo-controlled trial of 164 subjects with clinically stable, persistent asthma. A subset of subjects (n ؍ 45) underwent bronchoscopy with endobronchial biopsy and BAL at the end of a 6-week run-in period, during which all subjects received triamcinolone acetonide (TAA), 400 g bid. Airway tissue mast cells, eosinophils, neutrophils, macrophages, and T cells were quantified morphometrically along with determination of BAL tryptase. At the end of the run-in period, subjects were then randomized to receive salmeterol (42 g bid), placebo, or continue TAA for 16 weeks followed by a second bronchoscopy. Measurements and results: Outcome variables included airway tissue mast cells, eosinophils, neutrophils, macrophages, and T cells that were quantified morphometrically and BAL tryptase. Thirty-five subjects completed the treatment phase; an additional 10 subjects, who were randomized to either salmeterol or placebo after the run-in, had treatment failure. When the bronchoscopy results performed at the end of the run-in, prior to randomization, were analyzed, the treatment failure group demonstrated significantly more tissue mast cells as compared to the nontreatment failure group despite 6 weeks of therapy with TAA (p ؍ 0.04). BAL tryptase was also significantly higher in the treatment failure group (p < 0.0001). Of those subjects who completed the study, tissue mast cells and BAL tryptase did not change significantly within any of the treatment groups during the treatment phase (p > 0.05). Conclusions: Persistent elevations in airway tissue mast cells and BAL tryptase after treatment with TAA predict treatment failure in patients for whom discontinuation of ICS is being considered.
The role of the mast cell in the pathophysiology of asthma
Journal of Allergy and Clinical Immunology, 2006
There is compelling evidence that human mast cells contribute to the pathophysiology of asthma. Mast cells, but not T cells or eosinophils, localize within the bronchial smooth muscle bundles in patients with asthma but not in normal subjects or those with eosinophilic bronchitis, a factor likely to be important in determining the asthmatic phenotype. The mechanism of mast cell recruitment by asthmatic airway smooth muscle involves the CXCL10/CXCR3 axis, and several mast cell mediators have profound effects on airway smooth muscle function. The autacoids are established as potent bronchoconstrictors, whereas the proteases tryptase and chymase are being demonstrated to have a range of actions consistent with key roles in inflammation, tissue remodeling, and bronchial hyperresponsiveness. IL-4 and IL-13, known mast cell products, also induce bronchial hyperresponsiveness in the mouse independent of the inflammatory response and enhance the magnitude of agonist-induced intracellular Ca 21 responses in cultured human airway smooth muscle. There are therefore many pathways by which the close approximation of mast cells with airway smooth muscle cells might lead to disordered airway smooth muscle function. Mast cells also infiltrate the airway mucous glands in subjects with asthma, showing features of degranulation, and a positive correlation with the degree of mucus obstructing the airway lumen, suggesting that mast cells play an important role in regulating mucous gland secretion. The development of potent and specific inhibitors of mast cell secretion, which remain active when administered long-term to asthmatic airways, should offer a novel approach to the treatment of asthma. (J Allergy Clin
Mast cells are associated with exacerbations and eosinophilia in children with severe asthma
European Respiratory Journal, 2016
The role of mast cells in the pathogenesis of childhood asthma is poorly understood. We aimed to estimate the implication of airway mucosal mast cells in severe asthma and their relationship with clinical, functional, inflammatory and remodelling parameters.Bronchial biopsies were performed in 36 children (5–18 years) with severe asthma: 24 had frequent severe exacerbations and/or daily symptoms in the previous year (symptomatic group), and 12 had few symptoms and a persistent obstructive pattern (paucisymptomatic group). Nine children without asthma were included as control subjects. We assessed mast cells in the submucosa and airway smooth muscle using c-kit antibodies and in the entire biopsy area using Giemsa.The number of submucosal mast cells was higher in the symptomatic group than in the paucisymptomatic group (p=0.02). The number of submucosal mast cells correlated with the number of severe exacerbations (p=0.02, r=0.37). There were positive correlations between the number ...
Allergy, 2005
Background: Bronchial asthma is characterized by airways smooth muscle hypertrophy and infiltration of mast cells in the bronchial mucosa. The aim of this investigation was to study the distribution of mast cells in different compartments in the bronchial mucosa of allergic and nonallergic asthma in relation to airways remodeling. Methods: Bronchial biopsies were obtained from 29 subjects with allergic and nonallergic asthma and healthy controls. The biopsies were stained for mast cells by means of the tryptase specific antibody AA1. Extracellular deposition of mast cell products were judged on a semi-quantitative scale. Mast cells per mm 2 were counted in epithelium, lamina propria and the smooth muscle compartment. Smooth muscle was visualized by actin antibodies and the proportion of staining of the biopsy estimated. Laminin and tenascin layers were visualized by their respective antibodies. Results: Airways smooth muscle thickness was greater in allergic vs nonallergic asthma (P < 0.001). Mast cells were increased in all three compartments in both allergic and nonallergic asthma, with significantly higher numbers in smooth muscles in allergic asthma (P < 0.03). The extracellular deposition of mast cell products was more common in allergic than nonallergic asthma in lamina propria and smooth muscles (P ¼ 0.025; P ¼ 0.002, respectively). In patients with allergic asthma the numbers of mast cells with extracellular deposition of mast cell products were significantly correlated to the thickness of the laminin and tenascin layers. Conclusion: Our results suggest that there are large differences between allergic and nonallergic asthmatics as to mast cell activation and airways smooth muscle thickness. Our data implies that mast cells are causally involved in structural alterations in allergic asthma.
The Role of Mast Cells in IgE-Independent Lung Diseases
Clinical Reviews in Allergy & Immunology, 2020
Mast cells (MCs) are granular cells of the innate immune system which develop from CD34+/CD117+ progenitors and play a role in orchestrating adaptive immune responses. They have a well-known role in allergic reactions following immunoglobulin (Ig)E-mediated activation of the cell-surface expressed IgE high-affinity receptor (FcεRI). MCs can also respond to various other stimuli due to the expression of a variety of receptors including toll-like receptors (TLRs), immunoglobulin (IgG) receptors (FcγR), complement receptors such as C5a (CD88) expressed by skin MCs, neuropeptides receptors including nerve growth factor receptor, (NGFR), cytokines receptors such as (IL)-1R and IL-3R, and chemokines receptors including CCR-1 and CCR-3. MCs release three groups of mediators upon degranulation differentiated according to their chemical composition, storage, and time to release. These include preformed mediators (mainly histamine, tryptase, and chymase), de novo synthesized mediators such as...