Local production of IgE in the respiratory mucosa and the concept of entopy: does allergy exist in nonallergic rhinitis?

Chemical respiratory sensitization-Current status of mechanistic understanding, knowledge gaps and possible identification methods of sensitizers

Respiratory sensitization is a complex immunological process eventually leading to hypersensitivity following re-exposure to the chemical. A frequent consequence is occupational asthma, which may occur after long latency periods. Although chemical-induced respiratory hypersensitivity has been known for decades, there are currently no comprehensive and validated approaches available for the prospective identification of chemicals that induce respiratory sensitization, while the expectations of new approach methodologies (NAMs) are high. A great hope is that due to a better understanding of the molecular key events, new methods can be developed now. However, this is a big challenge due to the different chemical classes to which respiratory sensitizers belong, as well as because of the complexity of the response and the late manifestation of symptoms. In this review article, the current information on respiratory sensitization related processes is summarized by introducing it in the available adverse outcome pathway (AOP) concept. Potentially useful models for prediction are discussed. Knowledge gaps and gaps of regulatory concern are identified.

Chief Complaint: Nasal Congestion

Nasal obstruction is the subjective perception and objective state of insufficient airflow through the nose. Nasal congestion, conversely, describes a state of not just inadequate airflow or obstructive phenomena but also pressure- and mucus-related states to the patient. Nasal receptors belonging to the transient receptor potential (TRP) protein family mediate the sense of nasal patency via the trigeminal nerve. The transient receptor potential melastatin-8 (TRPM8) responds to temperatures around 8°C to 22°C, and is stimulated by menthol and other cooling agents. The radiant effects of airflow create heat loss to activate these receptors and humans perceive this as nasal patency rather than the direct detection of airflow. The thermovascular state of the mucosa, in conditions such as rhinitis, influence TRPM8 activation. Nasal endoscopy can show signs of rhinitis and should be considered an essential part of the workup of nasal congestion. Efforts to relieve nasal congestion need to manage the mucosal state and surgery needs to ensures that the nasal cavity mucosa is exposed to the cooling effects of airflow rather than simply creating a passage to the nasopharynx.

Anti-IL5 Therapies for Severe Eosinophilic Asthma: Literature Review and Practical Insights

Severe refractory asthma (SRA) still has a high economic and social impact, including a reduction in quality of life (QoL), productivity, a greater risk of exacerbations and emergency department (ED) visits. Another major issue is the need of oral corticosteroids (OCS), often due to a poor response to standard therapies or the lack of indication for currently available biological drugs. A thorough understanding of the immunological pathways and eosinophilopoietic processes allows a correct application of the new pharmacological strategies and leads to better clinical responses. For these unmet needs, several monoclonal antibody (mAb) drugs have been introduced over the past few years. These are mainly available for allergic and especially eosinophilic uncontrolled refractory asthma. As the number of therapeutic options increases, the choice of biological drugs can be made only after careful considerations of the particular asthma endotype, patients’ comorbidities and clinical data. The selection of the correct therapeutic option can therefore be guided after a careful evaluation of the particular endotype and phenotype, from the combined evaluation of inflammatory biomarkers, clinical picture and comorbidities. The careful evaluation of all these parameters can therefore help the physician in the optimal management of these complex patients, for whom it is often possible to achieve exceptional results by managing the available options in the best possible way. The aim of this review is to define the positioning of the biological drugs currently available for type 2 asthma, with a special focus on options for eosinophilic asthma in the context of the most recent knowledge of immunological pathways.

BSACI guideline for the diagnosis and management of allergic and non-allergic rhinitis (Revised Edition 2017; First edition 2007)

This is an updated guideline for the diagnosis and management of allergic and non-allergic rhinitis, first published in 2007. It was produced by the Standards of Care Committee of the British Society of Allergy and Clinical Immunology, using accredited methods. Allergic rhinitis is common and affects 10-15% of children and 26% of adults in the UK, it affects quality of life, school and work attendance, and is a risk factor for development of asthma. Allergic rhinitis is diagnosed by history and examination, supported by specific allergy tests. Topical nasal corticosteroids are the treatment of choice for moderate to severe disease. Combination therapy with intranasal corticosteroid plus intranasal antihistamine is more effective than either alone and provides second line treatment for those with rhinitis poorly controlled on monotherapy. Immunotherapy is highly effective when the specific allergen is the responsible driver for the symptoms. Treatment of rhinitis is associated with benefits for asthma. Non-allergic rhinitis also is a risk factor for the development of asthma and may be eosinophilic and steroid-responsive or neurogenic and non- inflammatory. Non-allergic rhinitis may be a presenting complaint for systemic disorders such as granulomatous or eosinophilic polyangiitis, and sarcoidoisis. Infective rhinitis can be caused by viruses, and less commonly by bacteria, fungi and protozoa.

Severe refractory asthma: current treatment options and ongoing research

Patients with severe asthma have a greater risk of asthma-related symptoms, morbidities, and exacerbations. Moreover, healthcare costs of patients with severe refractory asthma are at least 80% higher than those with stable asthma, mainly because of a higher use of healthcare resources and chronic side effects of oral corticosteroids (OCS). The advent of new promising biologicals provides a unique therapeutic option that could achieve asthma control without OCS. However, the increasing number of available molecules poses a new challenge: the identification and selection of the most appropriate treatment. Thanks to a better understanding of the basic mechanisms of the disease and the use of predictive biomarkers, especially regarding the Th2-high endotype, it is now easier than before to tailor therapy and guide clinicians toward the most suitable therapeutic choice, thus reducing the number of uncontrolled patients and therapeutic failures. In this review, we will discuss the different biological options available for the treatment of severe refractory asthma, their mechanism of action, and the overlapping aspects of their usage in clinical practice. The availability of new molecules, specific for different molecular targets, is a key topic, especially when considering that the same targets are sometimes part of the same phenotype. The aim of this review is to help clarify these doubts, which may facilitate the clinical decision-making process and the achievement of the best possible outcomes.

Local allergic rhinitis: evolution of concepts

The discovery of an exclusive local production of IgE antibodies dates back to the 1970s, but only recently the pathophysiology of such phenomenon was deeply investigated, leading to the concept of local allergic rhinitis (LAR). Currently, LAR is defined by the occurrence, in patients with symptoms clearly suggesting allergic rhinitis but with negative results to common allergy testing, of allergen specific IgE in the nasal mucosa. Most studies investigating LAR were based on the development of rhinitis symptoms following nasal provocation test (NPT) with the suspected allergens, but such test may be performed by a number of options, none of them being as yet acknowledged and recommended in consensus document. On the other hand, also the mere detection of IgE in the nasal mucosa indicates, as for IgE measurement in blood or other tissues, allergic sensitization but cannot give the certainty of clinical allergy. Therefore, the combination of IgE detection in nasal mucosa and a positive result of NPT should be used to diagnose LAR. Recent data on the use for in vitro testing of molecular allergy diagnostics in place of whole allergen extracts suggest that this method could improve the sensitivity and specificity of laboratory tests, and an appraisal of the basophil activation test as a third level technique, to be implemented when the results of local IgE testing and NPT are uncertain, is currently ongoing.

Innovative treatments for severe refractory asthma: how to choose the right option for the right patient?

The increasing understanding of the molecular biology and the etiopathogenetic mechanisms of asthma helps in identification of numerous phenotypes and endotypes, particularly for severe refractory asthma. For a decade, the only available biologic therapy that met the unmet needs of a specific group of patients with severe uncontrolled allergic asthma has been omalizumab. Recently, new biologic therapies with different mechanisms of action and targets have been approved for marketing, such as mepolizumab. Other promising drugs will be available in the coming years, such as reslizumab, benralizumab, dupilumab and lebrikizumab. Moreover, since 2010, bronchial thermoplasty has been successfully introduced for a limited number of patients. This is a nonpharmacologic endoscopic procedure which is considered a promising therapy, even though several aspects still need to be clarified. Despite the increasing availability of new therapies, one of the major problems of each treatment is still the identification of the most suitable patients. This sudden abundance of therapeutic options, sometimes partially overlapping with each other, increases the importance to identify new biomarkers useful to guide the clinician in selecting the most appropriate patients and treatments, without forgetting the drug-economic aspects seen in elevated direct cost of new therapies. The aim of this review is, therefore, to update the clinician on the state of the art of therapies available for refractory asthma and, above all, to give useful directions that will help understand the different choices that sometimes partially overlap and to dispel the possible doubts that still exist.

Is nonhomogeneous expression of tissue mast cells or allergen specific IgEs bound to tissue mast cells possible?

Skin prick tests (SPTs) are widely used to demonstrate an IgE-mediated hypersensitivity reaction to a specific allergen. However, local allergic conditions cannot be diagnosed with SPTs. Local specific IgE production was only presented before in mucosal tissues. We present a patient with house dust mite sensitization that had variable SPTs results in different body regions.

The role of local allergy in the nasal inflammation

Local allergic inflammation (LAI) is recognized recently. 'entopy' was used to define LAI, which was positively correlated with allergen provocation testing, local sIgE up-regulation, inflammatory mediator secretion, and a lack of systemic allergy. The study of LAI is in its infancy and focuses mainly on the respiratory system. It is closely related to nasal inflammation and plays important roles in patients with nonallergic rhinitis (NAR), nonallergic chronic sinusitis with nasal polyps (CRSwNP), and nonallergic fungal rhinosinusitis (NAFRS). Based on studies using nasal allergen provocation testing, 40-57% of patients with NAR exhibited positive results and could be diagnosed as local allergic rhinitis. Total IgE and common airborne allergen-sIgE were up-regulated in eosinophilic CRSwNP patients compared to noneosinophilic CRSwNP patients and healthy controls, possibly due to local allergic inflammation. Some researchers also found that the level of local sIgE was increased in patients with NAFRS; they suggested that local allergic inflammation occurs in NAFRS. Studies of LAI will increase our understanding of nasal inflammation and help to establish novel treatments. However, the diagnosis of local allergic inflammation is complex due to the lack of convenient detection methods. The relationship between local allergic inflammation and systemic allergic inflammation is unclear, and an appropriate treatment for local allergic inflammation is required.

Mepolizumab for severe refractory eosinophilic asthma: evidence to date and clinical potential

Severe asthma is characterized by major impairment of quality of life, poor symptom control and frequent exacerbations. Inflammatory, clinical and causative factors identify different phenotypes and endotypes of asthma. In the last few years, new treatment options have allowed for targeted treatments according to the different phenotypes of the disease. To accurately select a specific treatment for each asthmatic variant, the identification of appropriate biomarkers is required. Eosinophilic asthma is a distinct phenotype characterized by thickening of the basement membrane and corticosteroid responsiveness. This review reports the latest evidence on an anti-IL-5 monoclonal antibody, mepolizumab, a new and promising biological agent recently approved by the FDA specifically for the treatment of severe eosinophilic refractory asthma.

Tailored therapy for severe asthma

Patients with severe asthma or COPD have often a suboptimal symptom control due to inadequate treatment. A better understanding of pathogenetic mechanisms, phenotypes, endotypes and the new technologies available in the fields of molecular biology and immunogenetics have made it possible to synthesize specific monoclonal antibodies virtually able to interact with any target antigen, or to open a way for new therapeutic target options. At the moment, the only biologic drug available in clinical practice is omalizumab. To overcome the limits of omalizumab, the research has focused on new monoclonal antibodies presenting higher avidity for IgE (e.g. ligelizumab and lumiximab) and ability to interact also with low affinity IgE receptor (FcϵRII). At present, many new biological drugs with different mechanisms of action and targets are matter of research. It is very important to identify the asthmatic phenotype in order to select the most appropriate drug for the individual patient. The most promising agents are targeted against cytokines of Th2 pattern and related receptors, such as IL-2 (daclizumab) and IL-13 (lebrikizumab) or IL-5 in patients with hypereosinophilia (mepolizumab, reslizumab and benralizumab). Other interesting drugs have as a target TNF-α or its soluble receptor (infliximab, golimumab and etanercept) or IL-1 (canakinumab), a cytokine with an important systemic proinflammatory action. Finally, the discovery of increased levels of C5a in the airways of asthmatic patients has led to the synthesis of a specific monoclonal antibody (eculizumab). Further help should come from the identification of biomarkers that can guide in choosing the best treatment for the individual patient, such as IgE for omalizumab or periostin for lebrikizumab.

Prevalence of allergic rhinitis among adults in urban and rural areas of china: a population-based cross-sectional survey

Purpose

The aim of the present study was to compare the prevalence of self-reported and confirmable allergic rhinitis (AR) with positive skin prick test (SPT) results among adults living in urban and rural areas of China.

Methods

Adults from a community in Beijing and a village in Baoding were selected as representative urban and rural dwellers, respectively. All eligible residents were enrolled from the population register and received a face-to-face interview using modified validated questionnaires. Equal sets of randomly selected self-reporting AR-positive and AR-negative participants who responded to the questionnaires were also investigated using skin prick tests.

Results

A total of 803 participants in the rural area and a total of 1,499 participants in the urban area completed the questionnaires, with response rates being 75.9% and 81.5% respectively. The prevalence of self-reported AR of the rural area (19.1%) was significantly higher than that of the urban area (13.5%). The elementary school of educational level increased the risk of having AR (adjusted OR=2.198, 95% CI=1.072-2.236) .The positive SPT rates among subjects with self-reported AR in the rural and urban areas were 32.5% and 53.3%, respectively; the confirmable AR prevalence of 6.2% and 7.2% among the rural and urban adults, respectively.

Conclusions

The prevalence of confirmable AR is similar between rural and urban areas in China, although there is a higher prevalence of self-reported AR in the former.

Serum eosinophil cationic protein level in Chinese subjects with nonallergic and local allergic rhinitis and its relation to the severity of disease

BACKGROUND

Nonallergic rhinitis (NAR) is a common disease, and local allergic rhinitis (LAR) is a newly described entity that is called "entopy" in recent years. However, the etiology and incidence of NAR and LAR are uncertain. This study evaluates the incidence of LAR in Chinese subjects and serum eosinophil cationic protein (ECP) levels in patients with NAR and LAR and its relationship with symptom scores.

METHODS

Positive skin-prick tests (SPT), nasal allergen provocation testing (NAPT) to Dermatophagoides farinae (DF), serum Phadiatop tests, and symptom score evaluations were performed in 147 patients with nonatopic persistent rhinitis. LAR was diagnosed by positive NAPT to DF results. The serum ECP level was measured using the UniCAP100 automated system by enzyme-linked immunosorbent assay (Pharmacia Diagnostics, Uppsala, Sweden).

RESULTS

Twelve patients were diagnosed with LAR, and 135 patients were diagnosed with NAR. There was no statistical difference of the visual analog scale scores between the two groups. Serum ECP was significantly increased in the patients with NAR. Serum ECP in the LAR group showed no difference compared with the NAR group or the controls. In the NAR group, nasal obstruction, rhinorrhea, and total scores had close and statistically significant relationships with serum ECP level.

CONCLUSION

The present study provides the first evidence that LAR exists in Chinese subjects. This study also suggests that eosinophils and ECP take part in the pathogenesis of NAR. A local examination for ECP and specific IgE in nasal lavage fluid or secretions in patients with LAR should be performed in a future study.

Detecting local immunoglobulin E from mucosal brush biopsy of the inferior turbinates using microarray analysis

BACKGROUND

It has been previously demonstrated that local, antigen-specific immunoglobulin E (IgE) can be detected using a standard in vitro assay of lysed epithelial cells in saline, harvested via nasal mucosal brush biopsy (MBB). However, compared to surgical biopsy or serum, smaller amounts of IgE are harvested using MBB, making detection much more difficult. Microarray analysis (MA) requires less IgE for detection, making this an attractive option for MBB. The goals of this study were to compare MA to a standard IgE assay for detecting antigen-specific IgE from MBB and to test the association between the presence of multiple positive components on MA with specific IgE on standard assay and skin-prick testing (SPT) grade.

METHODS

MBB samples from 18 allergic rhinitis patients, which were previously tested for antigen-specific IgE to common airborne allergens using a standard IgE assay, underwent MA for antigen-specific IgE to multiple components of airborne and food allergens. Fisher's exact probability testing was used to measure the strength of association between the 2 testing modalities for Timothy grass, ragweed, cat, Alternaria, and D. farinae.

RESULTS

MA correlated very highly with standard assay (p < 0.0001) and 50% of positive antigens on MA detected multiple components to that antigen. The presence of multiple components was not associated with specific IgE levels on standard assay or SPT grade.

CONCLUSION

This is the first demonstration that antigen-specific IgE in saline samples can be measured using MA. The ability of MA to measure smaller amounts of IgE, with similar accuracy, may give it a potential advantage for MBB analysis in the future.

Microarrayed recombinant allergens for diagnostic testing

The development of protein microarray-based immunoassays and the availability of recombinant allergens have, to a significant extent, emerged together over the past decade. Their long-anticipated wider application to allergy diagnosis has recently begun to accelerate. This review discusses some of the strengths and weaknesses of molecularly defined allergy testing and the microarray platform. Several recent applications of microarray assays to allergy testing are also summarized. Promising findings, particularly in the context of food and latex allergy, point to the potential for greater resolution between clinical reactivity and asymptomatic sensitization with this platform.