Asthmatic airway neutrophilia after allergen challenge is associated with the glutathione S-transferase M1 genotype

Effect of Obesity on the Expression of Genes Associated with Severe Asthma-A Pilot Study

Asthma is a complex condition resulting from the interaction of genes and environment. Obesity is a risk factor to develop asthma and contributes to poor response to asthma therapy and severity. The aim of the study was to evaluate the effect of obesity on the expression levels of genes previously associated with severe asthma. Three groups of subjects were studied: non-obese asthmatics (NOA), obese asthma patients (OA), and non-asthmatic obese subjects (O). Previously reported overexpressed (IL-10, MSR1, PHLDA1, SERPINB2, and CD86) and underexpressed genes (CHI3L1, CPA3, IL-8, and PI3) in severe asthma were analyzed by RT-qPCR in peripheral blood mononuclear cells (PBMCs). In the overexpressed genes, obesity significantly decreased the expression of MSR1 and PHLDA1 and had no effects on CD86, IL-10, and SERPINB2. In underexpressed genes, obesity did not affect PI3, CHI3L1, and IL-8 and significantly reduced CPA3 expression. The results of this study show that obesity should be included among the known factors that can contribute toward modifying the expression of genes associated with asthma and, in particular, severe asthma.

Genetic Variation of Glutathione S-Transferase M1 Is Associated with Patients with Ovarian Endometriosis and Endometriosis-Related Primary Infertility

BACKGROUND

The aim of the study was to investigate the role of the genetic variation of glutathione S-transferase M1 (GSTM1) in the development of ovarian endometriosis and endometriosis-related primary infertility risk.

METHODS

This case-control study included 564 women with ovarian endometriosis and 576 normal women in the control group in northern China. The polymorphism of GSTM1 was genotyped by polymerase chain reaction (PCR)/ligase detection reaction method. To assess the biological significance of polymorphisms, the level of GSTM1 mRNA expression in patients' endometrial tissues with different genotypes was detected by quantitative real-time PCR (qRT-PCR).

RESULTS

Compared with the positive genotype, the null genotype of GSTM1 was associated with the risk of developing ovarian endometriosis (OR = 1.29, 95% CI = 1.02-1.62). Further analysis showed that patients with a null genotype also had a significantly higher risk of primary infertility than patients with positive genotypes (OR = 1.59, 95% CI = 1.01-2.49). In addition, we found that GSTM1 mRNA expression was present in the endometrial tissue of all patients, but the expression level of patients with a positive genotype was nearly 10 times higher than that of patients with a negative genotype.

CONCLUSION

Our results suggest that the GSTM1 polymorphism is not only related to the genetic susceptibility to ovarian endometriosis but also a potential molecular marker of primary infertility in patients with ovarian endometriosis.

Asthma Phenotypes and Endotypes: Implications for Personalised Therapy

Asthma is increasingly recognised as a heterogeneous group of diseases with similar clinical presentations rather than a singular disease entity. Asthma was historically categorised by clinical symptoms; however, newer methods of subgrouping, describing and categorising the disease have sub-defined asthma. These sub-definitions are intermittently called phenotypes or endotypes, but the real meanings of these words are poorly understood. Novel treatments are currently and increasingly available, partly in the monoclonal antibody environment, and also some physical therapies (bronchial thermoplasty), but additionally small molecules are not far away from clinical practice. Understanding the disease pathogenesis and the mechanism of action more completely may enable identification of treatable traits, biomarkers, mediators and modifiable therapeutic targets. However, there remains a danger that clinicians become preoccupied with the concept of endotypes and biomarkers, ignoring therapies that are hugely effective but have no companion biomarker. This review discusses our understanding of the concept of phenotypes and endotypes in appreciating and managing the heterogeneous condition that is asthma. We consider the role of functional imaging, physiology, blood-, sputum- and breath-based biomarkers and clinical manifestations that could be used to produce a personalised asthma profile, with implications on prognosis, pathophysiology and most importantly specific therapeutic responses. With the advent of increasing numbers of biological therapies and other interventional options such as bronchial thermoplasty, the importance of targeting expensive therapies to patients with the best chance of clinical response has huge health economic importance.

Mucosal Type 2 Innate Lymphoid Cells Are a Key Component of the Allergic Response to Aeroallergens

RATIONALE

Newly characterized type 2 innate lymphoid cells (ILC2s) display potent type 2 effector functionality; however, their contribution to allergic airways inflammation and asthma is poorly understood. Mucosal biopsy used to characterize the airway mucosa is invasive, poorly tolerated, and does not allow for sequential sampling.

OBJECTIVES

To assess the role of ILC2s during nasal allergen challenge in subjects with allergic rhinitis using novel noninvasive methodology.

METHODS

We used a human experimental allergen challenge model, with flow cytometric analysis of nasal curettage samples, to assess the recruitment of ILC2s and granulocytes to the upper airways of subjects with atopy and healthy subjects after allergen provocation. Soluble mediators in the nasal lining fluid were measured using nasosorption.

MEASUREMENTS AND MAIN RESULTS

After an allergen challenge, subjects with atopy displayed rapid induction of upper airway symptoms, an enrichment of ILC2s, eosinophils, and neutrophils, along with increased production of IL-5, prostaglandin D2, and eosinophil and T-helper type 2 cell chemokines compared with healthy subjects. The most pronounced ILC2 recruitment was observed in subjects with elevated serum IgE and airway eosinophilia.

CONCLUSIONS

The rapid recruitment of ILC2s to the upper airways of allergic patients with rhinitis, and their association with key type 2 mediators, highlights their likely important role in the early allergic response to aeroallergens in the airways. The novel methodology described herein enables the analysis of rare cell populations from noninvasive serial tissue sampling.

Advance of antioxidants in asthma treatment

Asthma is an allergic disease, characterized as a recurrent airflow limitation, airway hyperreactivity, and chronic inflammation, involving a variety of cells and cytokines. Reactive oxygen species have been proven to play an important role in asthma. The pathogenesis of oxidative stress in asthma involves an imbalance between oxidant and antioxidant systems that is caused by environment pollutants or endogenous reactive oxygen species from inflammation cells. There is growing evidence that antioxidant treatments that include vitamins and food supplements have been shown to ameliorate this oxidative stress while improving the symptoms and decreasing the severity of asthma. In this review, we summarize recent studies that are related to the mechanisms and biomarkers of oxidative stress, antioxidant treatments in asthma.

Neutrophilic inflammation in asthma: mechanisms and therapeutic considerations

INTRODUCTION

Neutrophilic airway inflammation represents a pathologically distinct form of asthma and frequently appears in symptomatic adulthood asthmatics. However, clinical impacts and mechanisms of the neutrophilic inflammation have not been thoroughly evaluated up to date. Areas covered: Currently, distinct clinical manifestations, triggers, and molecular mechanisms of the neutrophilic inflammation (namely Toll-like receptor, Th1, Th17, inflammasome) are under investigation in asthma. Furthermore, possible role of the neutrophilic inflammation is being investigated in respect to the airway remodeling. We searched the related literatures published during the past 10 years on the website of Pub Med under the title of asthma and neutrophilic inflammation in human. Expert commentary: Epidemiologic and experimental studies have revealed that the neutrophilic airway inflammation is induced by a wide variety of stimuli including ozone, particulate matters, cigarette smoke, occupational irritants, endotoxins, microbial infection and colonization, and aeroallergens. These triggers provoke diverse immune and inflammatory responses leading to progressive and sometimes irreversible airway obstruction. Clinically, neutrophilic airway inflammation is frequently associated with severe asthma and poor response to glucocorticoid therapy, indicating the need for other treatment strategies. Accordingly, therapeutics will be targeted against the main mediators behind the underlying molecular mechanisms of the neutrophilic inflammation.

Neutrophil recruitment by allergens contribute to allergic sensitization and allergic inflammation

PURPOSE OF REVIEW

To discuss the presence and role of neutrophils in asthma and allergic diseases, and outline the importance of pollen and cat dander-induced innate neutrophil recruitment in induction of allergic sensitization and allergic inflammation.

RECENT FINDINGS

Uncontrolled asthma is associated with elevated numbers of neutrophils, and levels of neutrophil-attracting chemokine IL-8 and IL-17 in bronchoalveolar lavage fluids. These parameters negatively correlate with lung function. Pollen allergens and cat dander recruit neutrophils to the airways in a toll-like receptor 4, myeloid differentiation protein-2, and chemokine (C-X-C motif) receptor (CXCR) 2-dependent manner. Repeated recruitment of activated neutrophils by these allergens facilitates allergic sensitization and airway inflammation. Inhibition of neutrophil recruitment with CXCR2 inhibitor, disruption of toll-like receptor 4, or small interfering RNA against myeloid differentiation protein-2 also inhibits allergic inflammation. The molecular mechanisms by which innately recruited neutrophils contribute to shifting the airway inflammatory response induced by allergens from neutrophilic to an eosinophilic-allergic is an area of active research.

SUMMARY

Recent studies have revealed that neutrophil recruitment is important in the development of allergic sensitization and inflammation. Inhibition of neutrophils recruitment may be a strategy to control allergic inflammation.

Facilitation of Allergic Sensitization and Allergic Airway Inflammation by Pollen-Induced Innate Neutrophil Recruitment

Neutrophil recruitment is a hallmark of rapid innate immune responses. Exposure of airways of naive mice to pollens rapidly induces neutrophil recruitment. The innate mechanisms that regulate pollen-induced neutrophil recruitment and the contribution of this neutrophilic response to subsequent induction of allergic sensitization and inflammation need to be elucidated. Here we show that ragweed pollen extract (RWPE) challenge in naive mice induces C-X-C motif ligand (CXCL) chemokine synthesis, which stimulates chemokine (C-X-C motif) receptor 2 (CXCR2)-dependent recruitment of neutrophils into the airways. Deletion of Toll-like receptor 4 (TLR4) abolishes CXCL chemokine secretion and neutrophil recruitment induced by a single RWPE challenge and inhibits induction of allergic sensitization and airway inflammation after repeated exposures to RWPE. Forced induction of CXCL chemokine secretion and neutrophil recruitment in mice lacking TLR4 also reconstitutes the ability of multiple challenges of RWPE to induce allergic airway inflammation. Blocking RWPE-induced neutrophil recruitment in wild-type mice by administration of a CXCR2 inhibitor inhibits the ability of repeated exposures to RWPE to stimulate allergic sensitization and airway inflammation. Administration of neutrophils derived from naive donor mice into the airways of Tlr4 knockout recipient mice after each repeated RWPE challenge reconstitutes allergic sensitization and inflammation in these mice. Together these observations indicate that pollen-induced recruitment of neutrophils is TLR4 and CXCR2 dependent and that recruitment of neutrophils is a critical rate-limiting event that stimulates induction of allergic sensitization and airway inflammation. Inhibiting pollen-induced recruitment of neutrophils, such as by administration of CXCR2 antagonists, may be a novel strategy to prevent initiation of pollen-induced allergic airway inflammation.

Myeloid differentiation protein 2 facilitates pollen- and cat dander-induced innate and allergic airway inflammation

BACKGROUND

The National Health and Nutrition Examination Survey identified several pollens and cat dander as among the most common allergens that induce allergic sensitization and allergic diseases. We recently reported that ragweed pollen extract (RWPE) requires Toll-like receptor 4 (TLR4) to stimulate CXCL-mediated innate neutrophilic inflammation, which in turn facilitates allergic sensitization and airway inflammation. Myeloid differentiation protein 2 (MD2) is a TLR4 coreceptor, but its role in pollen- and cat dander-induced innate and allergic inflammation has not been critically evaluated.

OBJECTIVE

We sought to elucidate the role of MD2 in inducing pollen- and cat dander-induced innate and allergic airway inflammation.

METHODS

TCM(Null) (TLR4(Null), CD14(Null), MD2(Null)), TLR4(Hi), and TCM(Hi) cells and human bronchial epithelial cells with small interfering RNA-induced downregulation of MD2 were stimulated with RWPE, other pollen allergic extracts, or cat dander extract (CDE), and activation of nuclear factor κB (NF-κB), secretion of the NF-κB-dependent CXCL8, or both were quantified. Wild-type mice or mice with small interfering RNA knockdown of lung MD2 were challenged intranasally with RWPE or CDE, and innate and allergic inflammation was quantified.

RESULTS

RWPE stimulated MD2-dependent NF-κB activation and CXCL secretion. Likewise, Bermuda, rye, timothy, pigweed, Russian thistle, cottonwood, walnut, and CDE stimulated MD2-dependent CXCL secretion. RWPE and CDE challenge induced MD2-dependent and CD14-independent innate neutrophil recruitment. RWPE induced MD2-dependent allergic sensitization and airway inflammation.

CONCLUSIONS

MD2 plays an important role in induction of allergic sensitization to cat dander and common pollens relevant to human allergic diseases.

Allergens Induce the Release of Lactoferrin by Neutrophils from Asthmatic Patients

Background

Despite the evidence that Lactoferrin (Lf) is involved in allergic asthma processes, it is unknown whether neutrophils can be one of the main cellular sources of this key inflammatory mediator directly in response of an IgE mediated stimulus. The present study was undertaken to analyze this question.

Methods

Neutrophils from healthy subjects (n = 34) and neutrophils from allergic asthmatic patients (n = 102) were challenged in vitro with specific allergens to which the patients were sensitized, PAF, or agonist mAbs against IgE-receptors, and the levels of Lf were measured in the culture supernatant. The levels of serum IgE together with the severity of symptoms were also analyzed.

Results

Lf was released into the culture supernatant of neutrophils from allergic asthmatic patients in response to allergens and PAF. This response was highly allergen-specific, and did not happen in neutrophils from healthy donors. Allergen effect was mimicked by Abs against FcεRI and galectin-3 but not by FcεRII. The levels of released Lf correlated well with the levels of serum specific IgE and severity of asthma symptoms. These observations represent a novel view of neutrophils as an important source of Lf in allergic asthma. Importantly, the levels of released Lf by neutrophils could therefore be used to evaluate disease severity in allergic asthmatic patients.

Children's Inter-Individual Variability and Asthma Development

Children of different ages vary in their response to environmental stressors due to their continuous development and changes in their bodies' anatomy, physiology, and biochemistry. Each age group of children has special biological features that distinguish their toxicokinetic and toxicodynamic characteristics from other age groups. The variability in responses extends to include children of the same age group. These intra- and inter-group differences in biological features explains the variability in responses to environmental exposures. Based on such differences in children's responses to exposures, adverse health outcomes and diseases develop differently in children. One of these diseases that are common in children is asthma. Asthma is a complex respiratory chronic disease that is multifactorial in origin. This paper discusses how variability in certain factors among children contributes to asthma occurrence or exacerbation, and links these factors to asthma in children of different ages. The importance of this review is to provide an insight on factors affecting asthma prevalence among children. These factors are usually overlooked in clinical or public health practice, which might significantly affect asthma management, and decrease the predictability of asthma detection measures. Therefore, keeping these factors into consideration can significantly improve asthma treatment and assist in asthma prevention amongst susceptible populations.

Innate responses to pollen allergens

PURPOSE OF REVIEW

The aim of the present review was to discuss the effects of pollen components on innate immune responses.

RECENT FINDINGS

Pollens contain numerous factors that can stimulate an innate immune response. These include intrinsic factors in pollens such as nicotinamide adenine dinucleotide phosphate oxidases, proteases, aqueous pollen proteins, lipids, and antigens. Each component stimulates innate immune response in a different manner. Pollen nicotinamide adenine dinucleotide phosphate oxidases induce reactive oxygen species generation and recruit neutrophils that stimulate subsequent allergic inflammation. Pollen proteases damage epithelial barrier function and increase antigen uptake. Aqueous pollen extract proteins and pollen lipids modulate dendritic cell function and induce Th2 polarization. Clinical studies have shown that modulation of innate immune response to pollens with toll-like receptor 9- and toll-like receptor 4-stimulating conjugates is well tolerated and induces clear immunological effects, but is not very effective in suppressing primary clinical endpoints of allergic inflammation.

SUMMARY

Additional research on innate immune pathways induced by pollen components is required to develop novel strategies that will mitigate the development of allergic inflammation.

Glutathione S-transferase M1 modulates allergen-induced NF-κB activation in asthmatic airway epithelium

BACKGROUND

Glutathione S-transferase M1 (GSTM1) is a phase II enzyme and regulator of inflammatory signaling in airway epithelial cells. We have found upregulation of neutrophilic airway inflammation in atopic asthmatics expressing GSTM1 gene (GSTM1+) compared to GSTM1null asthmatics. We hypothesized that GSTM1 modulates NF-κB activation in bronchial epithelium in atopic asthmatics. We determined regulation of allergen-induced NF-κB activation in bronchial epithelium by GSTM1 in human atopic asthmatics in vivo.

METHODS

Endobronchial biopsies and bronchoalveolar lavage fluid samples were collected from 13 GSTM1+ and 12 GSTM1null human atopic asthmatics at baseline and 24 h after segmental allergen challenge. A quantitative analysis of NF-κB activation in airway epithelium was accomplished using a polyclonal antibody against the phosphorylated p65 component of NF-κB. Elastase-positive neutrophils in the bronchial wall were quantified.

RESULTS

Postallergen neutrophilia in airway subepithelium and epithelial lining fluid was greater in GSTM1+ compared to GSTM1null asthmatics. Airway eosinophilia was similar in GSTM1+ and GSTM1null asthmatics. Allergen-provoked NF-κB induction in bronchial epithelium was significantly greater in GSTM1+ compared to GSTM1null asthmatics. Activation of NF-κB activation in airway epithelial cells correlated with interleukin-8 concentrations and absolute neutrophil numbers in bronchoalveolar lavage fluid in GSTM1+ but not GSTM1null asthmatics.

CONCLUSIONS

Allergen-induced neutrophilic airway inflammation in GSTM1+ asthmatics is associated with NF-κB activation in airway epithelial cells in vivo. These novel data provide a potential mechanism of the genomic link between GSTM1 polymorphism and airway neutrophilia in atopic asthma.

Gender-dependent effect of GSTM1 genotype on childhood asthma associated with prenatal tobacco smoke exposure

It remains unclear whether the GSTM1 genotype interacts with tobacco smoke exposure (TSE) in asthma development. This study aimed to investigate the interactions among GSTM1 genotype, gender, and prenatal TSE with regard to childhood asthma development. In a longitudinal birth cohort in Taiwan, 756 newborns completed a 6-year follow-up, and 591 children with DNA samples available for GSTM1 genotyping were included in the study, and the interactive influences of gender-GSTM1 genotyping-prenatal TSE on childhood asthma development were analyzed. Among these 591 children, 138 (23.4%) had physician-diagnosed asthma at 6 years of age, and 347 (58.7%) were null-GSTM1. Prenatal TSE significantly increased the prevalence of childhood asthma in null-GSTM1 children relative to those with positive GSTM1. Further analysis showed that prenatal TSE significantly increased the risk of childhood asthma in girls with null-GSTM1. Furthermore, among the children without prenatal TSE, girls with null-GSTM1 had a significantly lower risk of developing childhood asthma and a lower total IgE level at 6 years of age than those with positive GSTM1. This study demonstrates that the GSTM1 null genotype presents a protective effect against asthma development in girls, but the risk of asthma development increases significantly under prenatal TSE.

Sputum neutrophil count after bronchial allergen challenge is related to peripheral blood neutrophil chemotaxis in asthma patients

OBJECTIVE

The aim of this study was to estimate relations between sputum neutrophilia and the chemotactic activity of peripheral blood neutrophils after the bronchial allergen challenge in asthma patients.

MATERIALS AND METHODS

Fifteen patients with allergic asthma (AA), 13 patients with allergic rhinitis (AR), all sensitized to Dermatophagoides pteronyssinus, and 8 healthy subjects (HS) underwent bronchial challenge with D. pteronyssinus. Sputum and peripheral blood collection were performed 24 h before, 7 and 24 h after the bronchial challenge. Cell counts were determined by the May-Grünwald-Giemsa method. Neutrophil chemotaxis was analyzed by a flow cytometer; IL-8 levels were measured by ELISA.

RESULTS

Sputum neutrophil count and peripheral blood neutrophil chemotaxis of patients with AA were greater 7 and 24 h after the challenge compared with the baseline values and patients with AR and HS (P < 0.05). Moreover, a significant correlation was found between the neutrophil count in sputum and IL-8 levels, and the chemotactic activity of peripheral blood neutrophils 24 h after the bronchial challenge only the patients with AA (P < 0.05).

CONCLUSIONS

Increased sputum neutrophil count was found to be associated with an enhanced chemotactic activity of peripheral blood neutrophils during allergen-induced late-phase airway inflammation in patients with allergic asthma.

Oxidative Stress and Therapeutic Development in Lung Diseases

Oxidative stress has many implications in the pathogenesis of lung diseases. In this review, we provide an overview of Reactive Oxygen Species (ROS) and nitrogen (RNS) species and antioxidants, how they relate to normal physiological function and the pathophysiology of different lung diseases, and therapeutic strategies. The production of ROS/RNS from endogenous and exogenous sources is first discussed, followed by antioxidant systems that restore oxidative balance and cellular homeostasis. The contribution of oxidant/antioxidant imbalance in lung disease pathogenesis is also discussed. An overview of therapeutic strategies is provided, such as augmenting NO bioactivity, blocking the production of ROS/RNS and replacement of deficient antioxidants. The limitations of current strategies and failures of clinical trials are then addressed, followed by discussion of novel experimental approaches for the development of improved antioxidant therapies.

Neutrophils from allergic asthmatic patients produce and release metalloproteinase-9 upon direct exposure to allergens

BACKGROUND

Asthma is characterized by airway inflammation and remodelling in which matrix metalloproteinases (MMPs) play an important role. MMP-9 is the major MMP found in the bronchoalveolar lavage fluids and bronchial biopsies from patients with allergic asthma after allergen challenge, where it correlates with the count of neutrophils and macrophages. However, the cellular sources of MMP-9 in this inflammatory condition have not yet been clearly identified. This work was undertaken to analyse whether neutrophils may be a source of MMP-9 in the allergic asthma condition upon allergen challenge.

METHODS

Neutrophils from allergic asthmatic patients were in vitro stimulated, and the levels of MMP-9 release were measured in the cell culture supernatants using enzyme-linked immunosorbent assay (ELISA) and zymography.

RESULTS

We show that MMP-9 is released by neutrophils, but not by eosinophils from allergic asthmatic patients in response to allergens to which the patients were sensitized. Neutrophils also released MMP-9 in response to anti-IgE Abs, and agonist Abs against FcεRI, FcεRII/CD23 and galectin-3. Inhibitors of transcription and translation, actinomycin D and cycloheximide, partially cancelled this process, suggesting that MMP-9 is also de novo synthesized in response to stimuli. We also show evidence that the MAPKs, p38 and extracellular signal-regulated kinase, as well as the transcription factor NF-κB, are involved, as specific chemical inhibitors of these cell-signalling pathways abolished the anti-IgE/allergen-dependent MMP-9 release.

CONCLUSIONS

These data demonstrate that the exposure of neutrophils to allergens leads to generation of MMP-9, which may then lead to remodelling in asthma.

Histamine stimulates hydrogen peroxide production by bronchial epithelial cells via histamine H1 receptor and dual oxidase

Oxidative stress has been implicated in the pathogenesis of bronchial asthma. Besides granulocytes, the airway epithelium can produce large amounts of reactive oxygen species and can contribute to asthma-related oxidative stress. Histamine is a major inflammatory mediator present in large quantities in asthmatic airways. Whether histamine triggers epithelium-derived oxidative stress is unknown. We therefore aimed at characterizing human airway epithelial H2O2 production stimulated by histamine. We found that air-liquid interface cultures of primary human bronchial epithelial cells (BECs) and an immortalized BEC model (Cdk4/hTERT HBEC) produce H2O2 in response to histamine. The main source of airway epithelial H2O2 is an NADPH dual oxidase, Duox1. Out of the four histamine receptors (H1R-H4R), H1R has the highest expression in BECs and mediates the H2O2-producing effects of histamine. IL-4 induces Duox1 gene and protein expression levels and enhances histamine-induced H2O2 production by epithelial cells. Using HEK-293 cells expressing Duox1 or Duox2 and endogenous H1R, histamine triggers an immediate intracellular calcium signal and H2O2 release. Overexpression of H1R further increases the oxidative output of Duox-expressing HEK-293 cells. Our observations show that BECs respond to histamine with Duox-mediated H2O2 production. These findings reveal a mechanism that could be an important contributor to oxidative stress characteristic of asthmatic airways, suggesting novel therapeutic targets for treating asthmatic airway disease.

Allergen immunotherapy decreases LPS-induced NF-κB activation in neutrophils from allergic patients

BACKGROUND

Allergen-specific immunotherapy (IT) is widely used to treat allergic diseases. The molecular mechanisms have not been clarified yet completely. The present work was undertaken to analyze the effect of IT in the activation of NF-κB.

METHODS

Neutrophils from 15 pollen-allergic IT-treated patients, 10 untreated pollen-allergic patients, and 10 healthy donors were in vitro stimulated with LPS. NF-κB activation (p65/p52) was measured in their nuclear extracts by enzyme-linked immunosorbent assay (ELISA). IκBα phosphorylation, NF-κB-repressing factor (NRF) activation, and thromboxane A2 (TXA2 ) and Interleukin-8 (IL-8) release were measured by ELISA.

RESULTS

There was a positive correlation between the score of symptoms and NF-κB activation in human neutrophils. IT significantly decreased NF-κB activation levels in neutrophils compared with neutrophils from untreated patients. IκBα phosphorylation and NRF activation levels were, respectively, significantly lower and higher in neutrophils from IT-treated patients than from untreated patients. IL-8 and TXA2 release were significantly lower in neutrophils from IT-treated patients than from untreated patients.

CONCLUSIONS

IT positive effects are at least in part mediated by the negative regulation of NF-κB activation in human neutrophils. These observations represent a novel view of neutrophils as possible cell target to treat IgE-dependent diseases through NF-κB downmodulation.