Expression of IL-4, Cepsilon RNA, and Iepsilon RNA in the nasal mucosa of patients with seasonal rhinitis: effect of topical corticosteroids

The Role of IgE in Upper and Lower Airway Disease: More Than Just Allergy!

Immunoglobulin E (IgE) is a well-known key factor in allergic airway disease; however, its central role in non-allergic airway inflammation is often underestimated. In some airway diseases, IgE is produced as a result of allergic sensitization. However, in others, IgE production occurs despite the lack of a specific allergen. Although multiple pathways contribute to the production of IgE in airway disease, it is its activity in mediating the inflammatory response that is associated with disease. Therefore, an understanding of IgE as the unifying component of upper and lower airway diseases has important implications for both diagnosis and treatment. Understanding the role of IgE in each upper and lower airway disease highlights its potential utility as a diagnostic marker and therapeutic target. Further classification of these diseases by whether they are IgE mediated or non–IgE mediated, rather than by the existence of an underlying allergic component, accounts for both systemic and localized IgE activity. Improvements in diagnostic methodologies and standardization of clinical practices with this classification in mind can help identify patients with IgE-mediated diseases. In doing so, this group of patients can receive optimal care through targeted anti-IgE therapeutics, which have already demonstrated efficacy across numerous IgE-mediated upper and lower airway diseases.

B cells and upper airway disease: allergic rhinitis and chronic rhinosinusitis with nasal polyps evaluated

Introduction: The first mucosal site to encounter inhaled allergen, antigen, and microbes is the upper airway. It must perforce have a rapid system of environmental threat recognition and self-defense. B cells play a critical role in such airway host-defense, tissue surveillance, and immune modulation. Several common upper airway diseases can be defined in the expression of either exaggerated or dysregulated B-cell function within T2-high mucosal inflammatory states.Areas covered: In this review, the authors discuss the immunology of allergic rhinitis (AR) and chronic rhinosinusitis with nasal polyps (CRSwNP) in the context of highlighting key aspects of B-cell biology and function. The review is based on the findings of a literature search using the terms B cells, rhinitis, nasal polyps, and rhinosinusitis.Expert opinion: Despite the emerging role of B-cell overdrive and dysfunction in upper airway disease, studies are lacking specifics to B cells, particularly in association with sinonasal infection and mucosal inflammation. There is a pressing need to focus on how respiratory inflammation, alongside impaired or exaggerated B-cell function, amplifies and further dysregulates immune signaling pathways in the disease setting of AR and CRSwNP.

Food Intolerance of Unknown Origin: Caused by Mucosal Inflammation? A Pilot Study

INTRODUCTION

The prevalence of patients with food intolerance (FI) has increased significantly. Immunoglobulin (Ig)E-mediated food allergies (FAs) are detected by determining IgE antibodies and skin prick test. Carbohydrate malabsorptions are clarified with breath tests. However, these diagnostic measures cannot capture all intolerances and have limitations in case of gut-mediated FI. The aims of this pilot study were to evaluate different methods to determine intestinal mucosal IgE in patients with FA and to characterize the intestinal mucosa in patients with FI of unknown origin (FH).

METHODS

Patients with FA and FH were compared with healthy controls. To determine the IgE antibodies and the cytokines tumor necrosis factor (TNF)-α and interferon (IFN)-γ of the intestinal mucosal, a lavage was performed as part of an ileocolonoscopy and samples were taken using the cytobrush and biopsy forceps. In a subgroup, mucosal samples were also taken from the duodenum.

RESULTS

Data in homogenates of intestinal mucosal samples yielded the highest sensitivity for IgE antibody titers compared with lavage and cytobrush. Patients with FA presented increased intestinal TNF-α and low IFN-γ values. This was in contrast to FH patients, who showed low intestinal IgE antibodies and TNF-α levels, but increased IFN-γ values.

DISCUSSION

The determination of IgE antibodies to diagnose intestinal IgE-mediated FA is most reliable in intestinal mucosal samples. Increased TNF-α and low IFN-γ levels in patients with FA characterize an allergic reaction. Decreased TNF-α and increased IFN-γ levels in patients with FH indicate an inflammation-related intolerance reaction (see Visual Abstract, Supplementary Digital Content 1, http://links.lww.com/CTG/A520).

Mechanisms of Aeroallergen Immunotherapy: Subcutaneous Immunotherapy and Sublingual Immunotherapy

Allergen immunotherapy (AIT) is an effective way to treat allergic disorders, targeting the underlying mechanisms and altering the disease course by inducing a long-lasting clinical and immune tolerance to allergens. Although sublingual and subcutaneous routes are used in daily practice, many novel ways to decrease side effects and duration and increase efficacy have been pursued. Further studies are needed to develop biomarkers for the identification of AIT responder patients and also to use the developed knowledge in allergy prevention studies. Future directions in AIT include treatments for autoimmune diseases, chronic infections, organ transplantation, and breaking immune tolerance to cancer cells.

WITHDRAWN: Topical steroid for chronic rhinosinusitis without polyps

Review withdrawn from Issue 4, 2016. Replaced by new reviews 'Intranasal steroids versus placebo or no intervention for chronic rhinosinusitis' (Chong 2016a) and 'Different types of intranasal steroids for chronic rhinosinusitis' (Chong 2016b).

The editorial group responsible for this previously published document have withdrawn it from publication.

Local immunoglobulin e in the nasal mucosa: clinical implications

Immunoglobulin E (IgE) can be highly elevated in the airway mucosa independently of IgE serum levels and atopic status. Mostly, systemic markers are assessed to investigate inflammation in airway disease for research or clinical practice. A more accurate but more cumbersome approach to determine inflammation at the target organ would be to evaluate markers locally. We review evidence for local production of IgE in allergic rhinitis (AR) and chronic rhinosinusitis with nasal polyps (CRSwNP). Diagnostic and therapeutic consequences in clinical practice are discussed. We describe that the airway mucosa has the intrinsic capability to produce IgE. Moreover, not only do IgE-positive B cells reside within the mucosa, but all tools are present locally for affinity maturation by somatic hypermutation (SHM), clonal expansion, and class switch recombination to IgE. Recognizing local IgE in the absence of systemic IgE has diagnostic and therapeutic consequences. Therefore, we emphasize the importance of local IgE in patients with a history of AR or CRSwNP.

Cytokine profiles in allergic rhinitis

Allergic rhinitis, particularly seasonal allergic rhinitis, is considered a classic Th2-mediated disease, with important contributions to pathology by interleukins 4, 5 and 13. As such, allergic rhinitis is an excellent model for studying allergic inflammation, with findings potentially relevant to the mechanism of lower airways inflammation seen in allergic asthma. However, recent evidence has revealed roles for additional non-Th2 cytokines in asthma, including IL-17 family cytokines and epithelial-derived cytokines. Additionally, putative roles for epithelial-derived cytokines and innate lymphoid cells have been described in chronic rhinosinusitis with nasal polyps. Here, evidence for the involvement of different cytokines and cytokine groups in allergic rhinitis is considered.

B-lymphocyte lineage cells and the respiratory system

Adaptive humoral immune responses in the airways are mediated by B cells and plasma cells that express highly evolved and specific receptors and produce immunoglobulins of most isotypes. In some cases, such as autoimmune diseases or inflammatory diseases caused by excessive exposure to foreign antigens, these same immune cells can cause disease by virtue of overly vigorous responses. This review discusses the generation, differentiation, signaling, activation, and recruitment pathways of B cells and plasma cells, with special emphasis on unique characteristics of subsets of these cells functioning within the respiratory system. The primary sensitization events that generate B cells responsible for effector responses throughout the airways usually occur in the upper airways, tonsils, and adenoid structures that make up the Waldeyer ring. On secondary exposure to antigen in the airways, antigen-processing dendritic cells migrate into secondary lymphoid organs, such as lymph nodes, that drain the upper and lower airways, and further B-cell expansion takes place at those sites. Antigen exposure in the upper or lower airways can also drive expansion of B-lineage cells in the airway mucosal tissue and lead to the formation of inducible lymphoid follicles or aggregates that can mediate local immunity or disease.

Inflammatory Cell Patterns in the Nasal Mucosa of Patients with Idiopathic Rhinitis

Background

Nonallergic rhinitis comprises many subgroups of rhinitis (vasomotor rhinitis, nonallergic rhinitis with eosinophilia syndrome, occupational rhinitis, idiopathic rhinitis, etc. in which its main feature is known to be free of allergy. We evaluate the cellular infiltrate of subjects with idiopathic rhinitis and compare them with allergic and control counterparts for detecting underlying pathophysiology.

Methods

Subjects selected from patients admitted to Istanbul University Medical Faculty between 2006 and 2009 were classified into idiopathic rhinitis (n = 16; mean age, 26.5 years), allergic rhinitis (n = 17; mean age, 31.1 years), and the control (n = 25, mean age, 28.8 years) groups. Inferior turbinate specimens were collected using Gerritsma forceps. Skin-prick testing was performed. Immunohistochemical detection was performed using B7 (chymase, clone CC1) and G3 (tryptase, clone AA1) primary antibodies for mast cells, human eosinophil major basic protein (clone BMK-13) for eosinophils, and immunoglobulin E (IgE) Ab-1 for mast and plasma cells in epithelium, superficial, and deep submucosa.

Results

We found significantly higher levels of mast cells within the different sites of nasal mucosa of allergic and idiopathic subjects compared with normal mucosa (p < 0.05). Additionally, a significant increase was observed in IgE+ cells of the patients with allergic and idiopathic rhinitis compared with the controls (p < 0.05 for each) Eosinophils were significantly increased within the epithelium of allergic patients’ mucosa.

Conclusion

We seem to have supportive data about possible mechanisms of “idiopathic rhinitis” that suggests local allergic inflammation. The study results provided important information for further provocation and immunohistochemical studies analyzing the shared mechanism of allergic and idiopathic rhinitis.

The who, where, and when of IgE in allergic airway disease

Allergic asthma and allergic rhinitis/conjunctivitis are characterized by a T(H)2-dominated immune response associated with increased serum IgE levels in response to inhaled allergens. Because IgE is a key player in the induction and maintenance of allergic inflammation, it represents a prime target for therapeutic intervention. However, our understanding of IgE biology remains fragmentary. This article puts together our current knowledge on IgE in allergic airway diseases with a special focus on the identity of IgE-secreting cells ("who"), their location ("where"), and the circumstances in which they are induced ("when"). We further consider the therapeutic implications of the insights gained.

[Nonspecific IgE potential in nasal discharge for diagnosing allergic rhinitis]

Given that the nasal discharge of subjects with allergic rhinitis contains IgE, we studied nonspecific IgE potential in nasal discharge as a diagnostic marker for allergic rhinitis. We divided 38 adults into 2 groups, one with 22 with Japanese cedar pollinosis and one with 16 with watery rhinorrhea negative to MAST33. The pollinosis group was exposed to Japanese cedar pollen in an environmental exposure unit, and eosinophils in nasal discharge, serum total IgE, pollen-specific IgE, and local IgE in nasal discharge were examined for the 2 groups to determine IgE levels in nasal discharge using the Allerwatch rapid test. In the pollinosis group, nasal discharge IgE correlated significantly with the number of eosinophils. The nasal discharge IgE had higher specificity than the eosinophil examination, whereas nasal discharge eosinophils had higher sensitivity than the IgE examination. We thus found that measuring IgE and eosinophils in nasal discharge is useful for clinically diagnosing allergic rhinitis.

Topical steroid for chronic rhinosinusitis without polyps

BACKGROUND

Topical corticosteroid is used as part of a comprehensive medical treatment for chronic rhinosinusitis (CRS) without polyps. Nevertheless, there is insufficient evidence to show a clear overall benefit. Trials studying the efficacy of topical corticosteroid use various delivery methods in patients who have or have not had sinus surgery, which directly impacts on topical delivery and distribution.

OBJECTIVES

To assess the effects of topical steroid in patients with CRS without nasal polyps and perform a meta-analysis of symptom improvement data, including subgroup analysis by sinus surgery status and topical delivery methods.

SEARCH STRATEGY

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ISRCTN and additional sources for published and unpublished trials. The date of the most recent search was 9 July 2010.

SELECTION CRITERIA

All randomised trials in which a topically administered corticosteroid was compared with either a placebo, no treatment or alternative topically administered corticosteroid for the treatment of CRS without polyps in patients of any age.

DATA COLLECTION AND ANALYSIS

Two authors reviewed the search results and selected trials meeting the eligibility criteria, obtaining full texts and contacting authors where necessary. We documented our justification for the exclusion of studies. Two authors extracted data using a pre-determined standardised data form.

MAIN RESULTS

Ten studies (590 patients) met the inclusion criteria. The trials were of low (six trials) and medium (four trials) risk of bias. The primary outcome was sino-nasal symptoms. When compared to placebo, topical steroid improved symptom scores (standardised mean difference -0.37; 95% confidence interval (CI) -0.60 to -0.13, P = 0.002; five trials, n = 286) and had a greater proportion of responders (risk ratio 1.69; 95% CI 1.21 to 2.37, P = 0.002; four trials, n = 263). With a limited number of studies, the subgroup analyses of patients who had received sinus surgery versus those who had not was not significant (P = 0.35). Subgroup analyses by topical delivery method revealed more benefit when steroid was administered directly to the sinuses than with simple nasal delivery (P = 0.04). There were no differences between groups for quality of life and adverse events.

AUTHORS' CONCLUSIONS

Topical steroid is a beneficial treatment for CRS without polyps and the adverse effects are minor. It may be included in a comprehensive treatment of CRS without polyps. Direct delivery of steroid to the sinuses may bring more beneficial effect. Further studies comparing different topical drug delivery methods to the sinuses, with appropriate treatment duration (longer than 12 weeks), are required.

Bax-gene transfer enhances apoptosis by steroid treatment in human nasal fibroblasts

Gene therapy has become a focus not only in the study of cancer but also lifestyle-related diseases. In case of chronic rhinosinusitis with nasal polyps and aspirin-induced asthma, nasal polyps poorly respond to a local administration of steroid. The Bax and Bcl-2 proteins play important roles in the regulation of apoptosis. The treatment of steroid (prednisone) induced apoptosis in the fibroblast. The Bax accelerates apoptosis. Apoptosis is very important in the anti-inflammatory mechanism. In this study, we investigated whether the overexpression of Bax in human fibroblasts influences apoptosis by treatment with a steroid (prednisolone) in vitro. Human nasal fibroblasts were isolated from small pieces of nasal polyp and were transfected with a bax gene-bearing mammalian expression vector. Human nasal fibroblasts were transiently transfected with the expression vector hBaxpcDNA3 (Bax-NF) or native pcDNA3 (Neo-NF). Both transfectants (Bax-NF, Neo-NF) and wild-type-nasal fibroblast (wt-NF) were cultured in conditioning medium and treated with each concentration of prednisolone for 72 h. Prednisolone at a concentration of 10 ng/ml decreased the viability of Bax-NF compared to that of Bax-NF in the absence of prednisolone. The cytotoxicity of prednisolone to Bax-NF was significantly higher than that to Neo-NF or wt-NF (p < 0.01) and the susceptibility of Bax-NF to prednisolone was about 1,000 times that of Neo-NF or wt-NF. We found that the transfer of the exogenous bax gene enhanced the induction of apoptosis by steroid-treatment in human nasal fibroblasts. Therefore, we suggest that exogenous Bax protein expression by gene transfer might be useful for the treatment of nasal polyps. We will further the preclinical study in improving steroids dose and in adopting to transfer bax gene to the nasal polyps by intranasal injection, thus providing a more effective and safer way for the nasal polyps that poorly respond to a local administration of steroids.

Local and systemic IgE in the evaluation and treatment of allergy

Traditional descriptions of type I hypersensitivity and its manifestations center on systemic immunoglobulin E (IgE)-mediated reactions to inciting antigens. Hence, many current diagnostic and therapeutic measures are based on systemic skin testing for allergy, systemic pharmacotherapy, and immunotherapy. Recent developments in rhinology and pulmonology, particularly in defining the phenomenon of local IgE production in various airway inflammatory conditions, have an impact on both medical and surgical diagnosis and management of these conditions. This review includes a discussion of allergy as a systemic disease, current systemic diagnostic and management strategies for allergy, and local IgE presence and synthesis in the upper and lower airways.

Mast cell function is not altered by Coronin-1A deficiency

Coronin-1A is a WD repeat protein family member, highly expressed in all hematopoietic lineages, and acts as a regulator of F-actin dynamics and Ca2+ signaling. In Coro1a(Lmb3) mice results in inactivation of the protein and leads to disease resistance in a model of lupus erythematosus. In Coro1a(-/-) and Coro1a(Lmb3) mice, peripheral T cells exhibit impairments in survival, migration, activation, and Ca2+ flux. In this study, we show that in vitro-differentiated mast cells from Coro1a(Lmb3) mice are viable, developed normally, and are fully functional in assays of degranulation, cytokine secretion, and chemotactic migration, despite increased F-actin levels. In Coro1a(Lmb3) mast cells, Ca2+ flux in response to physiological FcεRI stimulation is unaffected. Finally, Coro1a(Lmb3) mice showed similar in vivo mast cell responses as the WT mice. Coronin-1B and Coronin-1C expression levels were not increased in Coro1a(Lmb3) mast cells but were higher in mast cells than in CD4 T cells or B cells in WT mice. We conclude that Coronin-1A activity is not required for mast cell function.

Germinal-centre reactions in allergic inflammation

Primary and secondary immune responses in the germinal centres of lymphoid organs have been studied in the past. There is now compelling evidence of a third stage in the immune response, in 'tertiary lymphoid organs' that develop at sites of chronic inflammation in response to persistent local antigen challenge. Germinal-centre-like reactions are well-documented in the target organs of autoimmune diseases. Here, we review recent evidence that they also occur at sites of allergic inflammation.

Mast cell survival and activation by IgE in the absence of antigen: a consideration of the biologic mechanisms and relevance

Mast cells are not only major effector cells in allergy and host defense against parasites and bacteria but also important cellular components in other immune responses. Recent studies on the effects of monomeric IgE on mast cell survival and activation have made an impact on our view of the IgE binding to its high-affinity receptors, Fc epsilonRI. Traditionally, IgE binding to Fc epsilonRI has been considered as a passive action of "sensitization" before receptor aggregation by Ag. However, recent studies indicate that at high concentrations some monoclonal IgEs have effects on mast cells similar to or identical to those induced by IgE+Ag stimulation. These effects may be due to induction of Fc epsilonRI aggregation by these IgEs in the absence of Ag. This review will synthesize recent findings of the heterogeneity of IgEs in their ability to induce survival and activation events, their mechanisms, the potential in vivo significance of IgE-Fc epsilonRI interactions, and the implications of the mouse studies to human diseases.

A quantitative analysis of cedar pollen-specific immunoglobulins in nasal lavage supported the local production of specific IgE, not of specific IgG

Many studies have proved the relevance of local immune responses, rather than systemic immunity, to the pathogenesis of allergic rhinitis. Indeed, allergen-specific B lymphocyte undergoes class switching to IgE in situ. However, the relative contribution of in situ production to the amount in serum is still ambiguous. Here, a quantitative comparison of the local concentration of allergen-specific IgE with the systemic concentration was explored for the estimation. Among seasonal rhinitis patients, total and Japanese cedar pollen (JCP)-specific IgE, IgA and IgG antibodies were quantified in nasal lavage fluid (NLF) and serum with the time-resolved fluorescence immunosorbent assay. Although the total amounts of IgE and IgG classes in the NLF, which were apparently passive discharge from the mucosal tissue, were smaller and variable, the relative proportions of JCP-specific antibodies could be quantitatively compared between NLF and serum or between subjects. The proportions of specific IgE in the NLF were remarkably higher than in serum (average 13.2-fold) in most subjects, which strongly supported the predominant in situ production of the specific IgE and subsequent dilutions in the systemic circulations. Similar but smaller values were obtained for IgA (average 3.7-fold). In contrast, the specific proportions of IgG in the NLF were surprisingly consistent with serum (average 1.0-fold), suggesting that the specific IgG was mostly produced in the downstream lymphoid organs. The local productions of specific IgE would encourage the topical therapies and the usage of the NLF for the diagnosis of allergic rhinitis.

Epsilon germ-line and IL-4 transcripts are expressed in human intestinal mucosa and enhanced in patients with food allergy

BACKGROUND

The mechanisms of gastrointestinal (GI) food allergy (FA) are poorly understood. Immunoglobulin E (IgE) is increased in stools from patients with FA, as well as the number of cells carrying IgE in intestinal mucosa, but the origin of IgE production remains unknown. To investigate a local production of IgE in intestine, we analysed the levels of transcripts for epsilon germ-line (epsilonGT), and potential regulators of IgE production, IL-4, IL-13, IFN-gamma, IL-4Ralpha, STAT6 and FcepsilonRIalpha in intestinal mucosa of adult patients with FA.

METHODS

Endoscopic biopsies were obtained from the caecum of 25 patients with FA and 14 control patients. The levels of epsilonGT, IL-4, IL-13, IFN-gamma, IL-4Ralpha, STAT6 and FcepsilonRIalpha mRNA were analysed by real-time RT-PCR and compared with unpaired nonparametric Mann-Whitney test.

RESULTS

The mean epsilonGT transcript level in caecum was increased in FA patients compared with control patients (P < 0.05). IL-4 mRNA expression was also increased in FA patients (P < 0.05), whereas mRNA expression for IL-13, IFN-gamma, IL-4Ralpha, STAT6 and FcepsilonRIalpha mRNA expression was not altered. However, the ratio of IL-4 mRNA/IFN-gamma mRNA was significantly increased in FA patients (P < 0.05). No correlation was observed between epsilonGT transcripts expression in intestinal mucosa and total IgE levels in serum.

CONCLUSIONS

This study shows that (i) epsilonGT transcripts are expressed in human intestinal mucosa; (ii) epsilonGT and IL-4 transcripts are increased in caecal mucosa from patients with FA. These results suggest local production of IgE in intestine that might be of importance for inflammatory reactions in the GI tract.

Allergen drives class switching to IgE in the nasal mucosa in allergic rhinitis

IgE-expressing B cells are over 1000 times more frequent in the nasal B cell than the peripheral blood B cell population. We have investigated the provenance of these B cells in the nasal mucosa in allergic rhinitis. It is generally accepted that expression of activation-induced cytidine deaminase and class switch recombination (CSR) occur in lymphoid tissue, implying that IgE-committed B cells must migrate through the circulation to the nasal mucosa. Our detection of mRNA for activation-induced cytidine, multiple germline gene transcripts, and epsilon circle transcripts in the nasal mucosa of allergic, in contrast to nonallergic control subjects, however, indicates that local CSR occurs in allergic rhinitis. The germline gene transcripts and epsilon circle transcripts in grass pollen-allergic subjects are up-regulated during the season and also when biopsies from allergic subjects are incubated with the allergen ex vivo. These results demonstrate that allergen stimulates local CSR to IgE, revealing a potential target for topical therapies in allergic rhinitis.

T lymphocytes and food allergy

Food allergy is a hypersensitivity reaction to normally harmless substances and involves humoral immune responses, mediated by immunoglobulin (IgE) synthesized by B lymphocytes, and cellular immune responses mediated by T lymphocytes. An IgE-mediated mechanism leads to clinical symptoms occurring immediately after food ingestion, e. g., "the oral allergy syndrome". For delayed reactions involving the gastrointestinal tract or the skin, the underlying immune mechanisms are less clear. In order to elucidate the cellular response to food allergens, human allergen-specific T cell cultures generated in vitro represent helpful tools. The majority of food allergen-specific CD4(+) T lymphocytes isolated from food-allergic individuals was found to synthesize high levels of IL-4 and IL-13, two cytokines required for initiation of IgE synthesis. Due to selective homing profiles, food-specific T cells seem also to be involved in defining the target organ of the allergic inflammation. Recent data provide evidence that in addition to IgE-mediated inflammation, food allergen-specific T lymphocytes may also cause inflammatory responses independently of IgE-mediated mechanisms.

IgE- and IgE+Ag-mediated mast cell migration in an autocrine/paracrine fashion

Mast cells are the major effector cells for immediate hypersensitivity and chronic allergic reactions. These cells accumulate in mucosal tissues of allergic reactions, where immunoglobulin E (IgE) is produced locally. Here we provide evidence that, in addition to antigen that can attract IgE-bound mast cells, the type of IgE molecules that efficiently activate mast cells can promote the migration of mast cells in the absence of antigen. IgE- and IgE+Ag-mediated migration involves an autocrine/paracrine secretion of soluble factors including adenosine, leukotriene B4, and several chemokines. Their secretion depends on 2 tyrosine kinases, Lyn and Syk, and they are agonists of G-protein-coupled receptors and signal through phosphatidylinositol 3-kinase gamma, leading to mast cell migration. In mouse experiments, naive mast cells are attracted to IgE, and IgE-sensitized mast cells are attracted to antigen. Therefore, IgE and antigen are implicated in mast cell accumulation at allergic tissue sites with local high IgE levels.

Cytokine expression in allergic inflammation: systematic review of in vivo challenge studies

BACKGROUND

Allergic inflammatory responses are driven by cells of the immune system that rely on cytokines to regulate the activity of other immune and structural cells.

OBJECTIVE

To review published studies to (1) identify cytokines consistently increased after allergen challenge in atopic patients and (2) investigate temporal variation in cytokine expression.

METHODS

A PUBMED systematic search was used to extract data from studies involving analysis of cytokine expression in fluids or biopsies following in vivo allergen challenge in atopic patients.

RESULTS

Data were extracted from 82 studies. There were no consistent reports of cytokine protein increase in fluids of patients at 0-1 h after challenge. At 4-12 h, the chemokines eotaxin, macrophage inflammatory protein-1alpha, RANTES (regulated on activation normal T cell expressed and secreted) and interleukin (IL)-8 have all been consistently reported to be up-regulated. At 18-24 h after challenge, the lymphokines IL-4, IL-5 and IL-13, as well as the pro-inflammatory cytokines granulocyte-macrophage colony-stimulating factor, tumour necrosis factor-alpha and IL-6 are consistently increased when compared with the respective control value. There were no reports of up-regulation in interferon-gamma protein and mRNA and in IL-2 mRNA.

CONCLUSION

The expression of granulocyte-macrophage colony-stimulating factor is consistently increased in tissues at 4-12 h after challenge. The influence of this cytokine on antigen capture and presentation by dendritic cells should be further investigated. Additionally, allergen challenge studies are needed that investigate the expression of macrophage-derived chemokine and thymus-regulated and activation-regulated chemokine in tissues of atopic patients. Blocking the effects of these lymphocyte-specific chemokines might provide new therapeutic approaches for the control of allergic inflammation.

Grass Pollen Immunotherapy Induces Mucosal and Peripheral IL-10 Responses and Blocking IgG Activity

T regulatory cells and IL-10 have been implicated in the mechanism of immunotherapy in patients with systemic anaphylaxis following bee stings. We studied the role of IL-10 in the induction of clinical, cellular, and humoral tolerance during immunotherapy for local mucosal allergy in subjects with seasonal pollinosis. Local and systemic IL-10 responses and serum Ab concentrations were measured before/after a double-blind trial of grass pollen (Phleum pratense, Phl P) immunotherapy. We observed local increases in IL-10 mRNA-positive cells in the nasal mucosa after 2 years of immunotherapy, but only during the pollen season. IL-10 protein-positive cells were also increased and correlated with IL-10 mRNA(+) cells. These changes were not observed in placebo-treated subjects or in healthy controls. Fifteen and 35% of IL-10 mRNA signals were colocalized to CD3(+) T cells and CD68(+) macrophages, respectively, whereas only 1-2% of total CD3(+) cells and 4% of macrophages expressed IL-10. Following immunotherapy, peripheral T cells cultured in the presence of grass pollen extract also produced IL-10. Immunotherapy resulted in blunting of seasonal increases in serum allergen Phl p 5-specific IgE, 60- to 80-fold increases in Phl p 5-specific IgG, and 100-fold increases in Phl p 5-specific IgG4. Post-immunotherapy serum exhibited inhibitory activity, which coeluted with IgG4, and blocked IgE-facilitated binding of allergen-IgE complexes to B cells. Both the increases in IgG and the IgG "blocking" activity correlated with the patients' overall assessment of improvement. Thus, grass pollen immunotherapy may induce allergen-specific, IL-10-dependent "protective" IgG4 responses.

Local somatic hypermutation and class switch recombination in the nasal mucosa of allergic rhinitis patients

Immunoglobulin E is produced by nasal B cells in response to allergen. We have analyzed IgE V(H) region sequences expressed in the nasal mucosa of patients suffering from allergic rhinitis. V(H) region sequences were amplified by RT-PCR from IgE(+) B cells from nasal biopsies. In two of six patients, sequence analysis clearly demonstrated the presence of closely related IgE(+) B cell clones: cells displaying identical signature regions across CDR3/FWR4, indicating a common clonal ancestry, but a mixture of shared and diverse somatic mutations across the V(H) region. Furthermore, in one of the two patients exhibiting related IgE(+) B cell clones, five IgA(+) B cell clones, related to the IgE(+) B cell family, were also isolated from the patient's nasal mucosa. This evidence, combined with the local expression of mRNA transcripts encoding activation-induced cytidine deaminase, suggests that local somatic hypermutation, clonal expansion, and class switch recombination occur within the nasal mucosa of allergic rhinitics. The presence of related B cells in the nasal mucosa does not appear to result from the random migration of IgE(+) cells from the systemic pool, as analysis of a nonatopic subject with highly elevated serum IgE did not exhibit any detectable V(H)-Cepsilon transcripts in the nasal mucosa. We have provided evidence that suggests for the first time that the nasal mucosa of allergic rhinitics is an active site for local somatic hypermutation, clonal expansion, and class switch recombination, making it of major significance for the targeting of future therapies.

S epsilon S mu and S epsilon S gamma switch circles in human nasal mucosa following ex vivo allergen challenge: evidence for direct as well as sequential class switch recombination

B cells switch to IgE under the influence of IL-4, IL-13, and CD40 costimulation through a multistep process involving epsilon germline transcription and class switch recombination. Classically, switching has been considered an event restricted to lymphoid tissues; however, epsilon germline transcripts (I(initiator)epsilon RNA) have been observed within lung, sinus, and nasal tissue of individuals with asthma, sinusitis, and rhinitis. Furthermore, nasal mucosal tissue from allergic rhinitics produces epsilon germline transcripts following ex vivo allergen challenge. Collectively, these studies raised the possibility that switching to IgE may occur locally, at sites of allergic inflammation. Although epsilon germline transcripts are considered necessary to target the IgE locus, it is class switch recombination that ultimately leads to de novo IgE production. In this study, we demonstrate that S epsilon S mu DNA switch circles (products of class switch recombination) as well as I epsilon and C epsilon RNA are produced within nasal tissue from allergic individuals following ex vivo allergen challenge. epsilon germline transcription was inhibited when tissue was cultured with a combination of allergen and neutralizing Abs against IL-4 and IL-13, indicating that de novo cytokine production mediated the isotype switch. We also show allergen-induced appearance of S epsilon S gamma DNA switch circles and up-regulation of C gamma 4 mRNA, illustrating that sequential switching to IgE also occurred. This work strongly suggests that B cells residing within the nasal mucosa undergo switching to IgE in the context of a local immune response to allergen.

Molecular immunology and immunotherapy for chronic sinusitis

The development of chronic sinusitis is a complex multifactorial process characterized by inflammation of nasal and sinus mucosa. Many studies have shown that the composition of the inflammatory substrate in chronic sinusitis is similar to that seen in allergic rhinitis and in the late-phase response to antigen challenge. Mononuclear cells, consisting of T and B lymphocytes and activated eosinophils, are prominent in the sinus mucosa of patients with chronic sinusitis, especially in atopic patients. Cellular recruitment and activation of the inflammatory infiltrate have been largely attributed to the effects of T(H)2 cytokines (namely interleukin -4, IL-5, IL-13, and granulocyte-macrophage colony-stimulating factor). Current treatment of allergic chronic sinusitis consists of nasal corticosteroids and immunotherapy. A subgroup of steroid-insensitive patients demonstrates an overexpression of a variant of the glucocorticoid receptor (GR). Despite these advances, the management and treatment of chronic sinusitis is often fraught with failures and remains a frustrating task for both physician and patient.

The biology of IGE and the basis of allergic disease

Allergic individuals exposed to minute quantities of allergen experience an immediate response. Immediate hypersensitivity reflects the permanent sensitization of mucosal mast cells by allergen-specific IgE antibodies bound to their high-affinity receptors (FcepsilonRI). A combination of factors contributes to such long-lasting sensitization of the mast cells. They include the homing of mast cells to mucosal tissues, the local synthesis of IgE, the induction of FcepsilonRI expression on mast cells by IgE, the consequent downregulation of FcgammaR (through an insufficiency of the common gamma-chains), and the exceptionally slow dissociation of IgE from FcepsilonRI. To understand the mechanism of the immediate hypersensitivity phenomenon, we need explanations of why IgE antibodies are synthesized in preference to IgG in mucosal tissues and why the IgE is so tenaciously retained on mast cell-surface receptors. There is now compelling evidence that the microenvironment of mucosal tissues of allergic disease favors class switching to IgE; and the exceptionally high affinity of IgE for FcepsilonRI can now be interpreted in terms of the recently determined crystal structures of IgE-FcepsilonRI and IgG-FcgammaR complexes. The rate of local IgE synthesis can easily compensate for the rate of the antibody dissociation from its receptors on mucosal mast cells. Effective mechanisms ensure that allergic reactions are confined to mucosal tissues, thereby minimizing the risk of systemic anaphylaxis.

Allergic and nonallergic forms of atopic diseases

Atopic dermatitis, allergic rhinitis, and asthma are atopic diseases that develop on a complex genetic background, the so-called atopic diathesis. Although they target different organs, in most patients they are characterized by the presence of elevated total serum IgE levels. However, a subgroup of atopic patients exhibits normal IgE levels and mechanisms contributing to the so-called "intrinsic" or "nonallergic form" have been the matter of intensive research work in the last years. Because of the rapid advancements in the research field of atopic diseases, it now becomes possible for the first time to delineate a new disease classification of allergic and nonallergic subtypes of atopic diseases, thereby bringing hope to the clinician for a more specific treatment approach for each subgroup of these patients.

Induction of IL-10+CD4+CD25+ T cells by grass pollen immunotherapy

BACKGROUND

Immunotherapy involves the modulation of allergen-specific T-cell responses, either T(H)2-to-T(H)1 immune deviation or, in bee venom-treated patients, induction of IL-10 production by CD4+CD25+ T cells. IL-10-producing CD4+CD25+ regulatory T cells have emerged as potential mediators of immune tolerance in numerous murine models of immunopathology.

OBJECTIVE

The aim of this study was to evaluate the role of IL-10 production and CD4+CD25+ T cells in the response to grass pollen immunotherapy.

METHODS

PBMCs were isolated from patients after 1 year of grass pollen immunotherapy and from matched untreated atopic and healthy control subjects. After 6 days of in vitro stimulation with Phleum pratense, production of IL-10, IL-5, IL-4, and IFN-gamma and proliferation and numbers of CD4+CD25+ T cells were measured. T cells were then stimulated for a further 5 hours with phorbol 12-myristate 13-acetate and ionomycin and assessed for intracellular IL-10 by means of flow cytometry.

RESULTS

Patients undergoing immunotherapy produced significantly more IL-10 than atopic control subjects (patients undergoing immunotherapy, 116 +/- 21 pg/mL [n = 11]; atopic patients, 30 +/- 5 pg/mL [n = 11]; P <.001), and the number of CD4+CD25+ cells identified after allergen stimulation was also greater in the immunotherapy group. The numbers of CD4+CD25+ T cells correlated positively with activation as measured by proliferation in both of the control groups but not in the immunotherapy group. Moreover, only T cells from patients undergoing immunotherapy were positive for intracellular IL-10, and these were almost exclusively CD4+CD25+ cells.

CONCLUSION

Grass pollen immunotherapy results in a population of circulating T cells that express the IL-10(+) CD4+CD25+ phenotype in response to allergen restimulation.

Local IgE synthesis in allergic rhinitis and asthma

Local IgE production has been a contentious concept for over 40 years. Although a host of clinical observations suggested a local source of IgE, co-localization of IgE to B cells in the nasal mucosa could not be demonstrated. In contrast, igE-producing B cells were observed in local lymphoid tissue. Definitive proof of local IgE synthesis in the nasal mucosa has now become available. Here, we review the recent developments in local IgE research in allergic rhinitis and asthma within their historical context, and speculate on the implications of both local IgE synthesis and ongoing research into local immunoglobulin isotype switching for patient therapy.

Novel insights into class switch recombination

The discovery of activation-induced cytidine deaminase, a putative RNA editing enzyme essential for both class switch recombination and somatic hypermutation, marked the field of isotype switching studies in the year 2000. More recent work from the same group now highlights some essential mechanistic aspects of the switch recombination process. In particular, much has been learnt about the relationship between transcription and recombination and the transcriptional competence of intronic promoters on looped-out circular DNA uncoupled from the proximal and distal enhancers. These findings have far-reaching implications, particularly for studies of class switch recombination in tissues. Although these important advances do not directly relate to interleukin-4-dependent immunoglobulin E switching, the conceptual and experimental tools developed through these studies are certain to foster progress in the immunoglobulin E field.

Increases in allergen-specific IgE in BAL after segmental allergen challenge in atopic asthmatics

IgE is important in both early and late allergic responses. Increases in the numbers of RNA transcripts coding for IgE have been observed in the bronchial mucosa of asthmatics and in the nasal mucosa of hay fever patients both during natural allergen exposure and after nasal allergen challenge, suggesting that IgE may be synthesized locally in the mucosa. In this study we have examined bronchoalveolar lavage (BAL) taken before and 24 h after bronchoscopic segmental allergen challenge from 18 atopic asthmatic patients, looking for evidence of increases in IgE protein. Allergen-specific IgG and total and allergen-specific IgE were measured in BAL using a fluoroenzyme immunoassay. There was a significant increase in allergen-specific IgE (Ku/L) in the BAL after allergen challenge [before [median (interquartile range)] 0 (0, 0); after 0.35 (0, 1.87): p = 0.009] which was not observed for allergen-specific IgG (p = 1.0) or for IgE specific to an allergen to which the subject was sensitized but was not used for provocation (p = 1.0). Correction for corresponding increases in total IgE, albumin, and urea in BAL did not affect the observed changes in allergen-specific IgE. These data indicate that allergen provocation results in a selective local accumulation of isotype-specific and allergen-specific IgE antibody within the bronchi, independent of alterations in circulating IgE.

Mode of action of intranasal corticosteroids

The mode of action of intranasal corticosteroids (INCS) is complex. It is not known whether INCS penetrate the nasal mucosa or act on target cells; however, their low systemic activity supports the concept of local action on nasal mucosa. This local effect can nonetheless influence a variety of inflammatory cells and their mediators such as epithelial cells, lymphocytes, basophils, mast cells, and Langerhans cells. Corticosteroid-induced inhibition of immunoglobulin E-dependent release of histamine is a possible but unproven mode of action. Epithelial cells are an important target for corticosteroids, and INCS concentration is high at the epithelial surface. INCS may combine with the corticosteroid receptors in epithelial cells, which are then expelled into the airway lumen together with the dead epithelial cells or migrating inflammatory cells. A reduced influx of mediator cells may explain some of the effects of INCS on rhinitis symptoms, but it cannot explain all of the effects because INCS also reduce the early-phase sneezing and rhinorrhea after an allergen challenge outside the pollen season. In this situation, the number of surface mast cells/basophils is very low, as it is in the absence of allergic rhinitis. The mechanism by which INCS treatment of allergic rhinitis reduces itching, sneezing, and rhinorrhea, the characteristic symptoms of an early-phase response involving mast cell release of histamine, remains to be determined. Studies should be conducted to characterize the broad range of mechanisms by which INCS produce their therapeutic effects in allergic rhinitis.

Inflammatory patterns of allergic and nonallergic rhinitis

Rhinitis is a chronic condition of the nasal mucosa that affects a large segment of the population. The symptoms of rhinitis occur in a variety of sinonasal conditions, which may be broadly classified as allergic (seasonal or perennial) or nonallergic (infectious or a number of noninfectious etiologies) based on the presence or absence of atopy. The cytokine profile and inflammatory patterns underlying these two conditions vary because of certain differences in their pathophysiology as discussed in this review.

Local expression of epsilon germline gene transcripts and RNA for the epsilon heavy chain of IgE in the bronchial mucosa in atopic and nonatopic asthma

BACKGROUND

The demonstration of epsilon germline gene (Cepsilon) transcripts and mature mRNA for the epsilon heavy chain gene (Iepsilon) in the nasal mucosa suggested that IgE synthesis may occur in allergic rhinitis.

OBJECTIVE

In view of our previous demonstration of increases in IL-4 mRNA(+) cells in asthmatic subjects, we assessed whether local IgE synthesis may also be a feature of bronchial asthma.

METHODS

Fiberoptic bronchoscopic mucosa biopsy specimens were obtained from 9 atopic asthmatic subjects and 10 nonatopic normal (intrinsic) control subjects. To control for atopy, we also studied 9 nonatopic asthmatic subjects and 10 atopic nonasthmatic control subjects. Tissue was processed for immunohistochemistry for B cells (CD20) and in situ hybridization for Iepsilon and Cepsilon RNA(+) cells and IL-4 mRNA(+) cells.

RESULTS

B-cell numbers in the bronchial mucosa were similar for asthmatic subjects compared with control subjects, whereas significantly higher numbers of Iepsilon RNA(+) (P =.02 and P =.04, respectively), Cepsilon RNA(+) (P =.01 and P =.03, respectively), and IL-4 mRNA(+) (P =.001 and P =.001, respectively) cells were observed in atopic asthmatic subjects and nonatopic asthmatic subjects, respectively, but not in atopic control subjects compared with nonatopic control subjects. In asthmatic subjects there were significant correlations between Iepsilon RNA(+) cells (r = 0.54, P =.02) and Cepsilon RNA(+) cells (r = 0.48, P =.05) when compared with the number of IL-4 mRNA(+) cells.

CONCLUSION

Increases in Iepsilon and Cepsilon RNA(+) cells, but not B-cell numbers, in the bronchial mucosa provide evidence for local IgE synthesis in both atopic and nonatopic asthma. These changes appear to relate to asthma rather than atopy per se and, at least in part, may be under the regulation of IL-4.

Total and specific IgE in nasal polyps is related to local eosinophilic inflammation

BACKGROUND

Nasal polyps (NPs) are characterized by eosinophilic inflammation and often coexist with asthma. However, the role of atopy and IgE in NP pathogenesis is unclear.

OBJECTIVE

We sought to determine whether there is an association between total and specific IgE to a variety of allergens in polyp and nonpolyp tissue and markers of eosinophilic inflammation or skin test results.

METHODS

Homogenates were prepared from nasal tissue of 20 patients with NPs and 20 patients without NPs and analyzed for concentrations of IL-5, IL-4, eotaxin, leukotriene (LT) C4/D4/E4, sCD23, and histamine (ELISA). Eosinophil cationic protein (ECP), tryptase, and total and specific IgE for inhalant allergens and Staphylococcus aureus enterotoxins were measured (ImmunoCAP).

RESULTS

The concentrations of total IgE, IL-5, eotaxin, ECP, LTC4/D4/E4, and sCD23 were significantly higher in NP tissue compared with nonpolyp tissue. Total IgE was significantly correlated to IL-5, ECP, LTC4/D4/E4, and sCD23 and to the number of eosinophils in NPs. On the basis of the presence of specific IgE antibodies in tissue, 3 NP groups were defined. NP group 1 demonstrated no measurable specific IgE, and NP group 2 selected specific IgE. The third group demonstrated a multiclonal specific IgE, including IgE to S aureus enterotoxins, a high total IgE level, and a high prevalence of asthma.

CONCLUSIONS

These studies suggest that there is an association between increased levels of total IgE, specific IgE, and eosinophilic inflammation in NPs, which may be of relevance in the pathophysiology of nasal polyposis. Similarly, the presence of specific IgE to staphylococcal enterotoxins A and B also points to a possible role of bacterial superantigens.

Regulation of allergic airways inflammation by cytokines and glucocorticoids

Cytokines mediate the allergic inflammatory response of the airways, and glucocorticosteroids ameliorate allergy symptoms by regulating cytokine expression. Recent studies provide insight into the manner by which cytokines work together to mediate allergic airway disease. Real progress has also been gained in our understanding of subcellular mechanisms of allergic inflammation, particularly the role of transcription factors in regulating the expression of specific cytokine profiles and the differentiation of the TH2 subset. This article provides an update of recently reported findings in this field and highlights emerging concepts of allergic inflammation.

A comparison of the anti-inflammatory properties of intranasal corticosteroids and antihistamines in allergic rhinitis

Allergic rhinitis manifests itself clinically due to the local release of mediators from activated cells within the nasal mucosa. Treatment strategies aim either to reduce the effects of these mediators on the sensory neural and vascular end organs, or to reduce the tissue accumulation of the activated cells that generate them. Corticosteroids intervene at a number of steps in the inflammatory pathway, and, by reducing the release of cytokines and chemokines, inhibit cell recruitment and activation. These effects are evident both in vivo and in vitro. While antihistamines also have some anti-inflammatory effects in vitro, these require higher concentrations than with corticosteroids and are not consistently reproduced in vivo. In addition, although antihistamines and corticosteroids might appear to have complementary mechanisms of action, clinical trials suggest that their co-administration does not confer any additional long-term benefits compared with that achieved with corticosteroids alone. Topical corticosteroids are therefore the preferred anti-inflammatory therapy for persistent allergic rhinitis.

Recruitment of CD1a+ Langerhans cells to the nasal mucosa in seasonal allergic rhinitis and effects of topical corticosteroid therapy

BACKGROUND

Local antigen presentation may be necessary for both primary and recall T-cell responses to grass pollen in hay fever patients. We examined the effect of seasonal allergen exposure on nasal mucosal antigen-presenting cell (APC) populations and the effects of topical corticosteroid therapy.

METHODS

Nasal biopsies were collected from 46 grass pollen-sensitive seasonal rhinitis patients before the grass-pollen season. A second biopsy was collected during the pollen season, when patients had received 6 weeks' treatment with either fluticasone propionate (200 microg, twice daily) or placebo. Cell populations in biopsy sections were quantified by immunocytochemistry.

RESULTS

Significant increases in submucosal and epithelial CD1a+ Langerhans cells, but not CD68 + macrophages or CD20 + B cells, were observed during the pollen season. Seasonal increases in CD1a+ Langerhans cells were inhibited by corticosteroid therapy.

CONCLUSIONS

Recruitment of CD1a+ Langerhans cells to the nasal mucosa during natural seasonal allergen exposure may contribute to local T cell responses. Topical corticosteroids may act, at least in part, by inhibiting effective allergen presentation to T cells through inhibition of recruitment of Langerhans cells to the nasal mucosa.

Recruitment of T cells to the lung in response to antigen challenge

T-cell recruitment to the lungs is thought to represent a key step in airway allergic inflammation. T cells coordinate and amplify effector functions of antigen-specific and nonspecific proinflammatory cells, such as B cells and eosinophils. The T(H)2 cell, in particular, promotes allergic inflammation through the expression of IL-4, IL-5, and IL-13, proinflammatory cytokines that are important in the induction of B-cell switching and the promotion of eosinophil proliferation and survival. This cytokine profile has been implicated in asthma; elevations in bronchoalveolar lavage IL-4 and IL-5 levels have been observed in asthmatic patients. The recruitment of T(H) cells to the site of allergic inflammation (lung) is the subject of this review.