The effect of omalizumab on nasal allergic inflammation

A robust mRNA signature obtained via recursive ensemble feature selection predicts the responsiveness of omalizumab in moderate-to-severe asthma

BACKGROUND

Not being well controlled by therapy with inhaled corticosteroids and long-acting β2 agonist bronchodilators is a major concern for severe-asthma patients. The current treatment option for these patients is the use of biologicals such as anti-IgE treatment, omalizumab, as an add-on therapy. Despite the accepted use of omalizumab, patients do not always benefit from it. Therefore, there is a need to identify reliable biomarkers as predictors of omalizumab response.

METHODS

Two novel computational algorithms, machine-learning based Recursive Ensemble Feature Selection (REFS) and rule-based algorithm Logic Explainable Networks (LEN), were used on open accessible mRNA expression data from moderate-to-severe asthma patients to identify genes as predictors of omalizumab response.

RESULTS

With REFS, the number of features was reduced from 28,402 genes to 5 genes while obtaining a cross-validated accuracy of 0.975. The 5 responsiveness predictive genes encode the following proteins: Coiled-coil domain- containing protein 113 (CCDC113), Solute Carrier Family 26 Member 8 (SLC26A), Protein Phosphatase 1 Regulatory Subunit 3D (PPP1R3D), C-Type lectin Domain Family 4 member C (CLEC4C) and LOC100131780 (not annotated). The LEN algorithm found 4 identical genes with REFS: CCDC113, SLC26A8 PPP1R3D and LOC100131780. Literature research showed that the 4 identified responsiveness predicting genes are associated with mucosal immunity, cell metabolism, and airway remodeling.

CONCLUSION AND CLINICAL RELEVANCE

Both computational methods show 4 identical genes as predictors of omalizumab response in moderate-to-severe asthma patients. The obtained high accuracy indicates that our approach has potential in clinical settings. Future studies in relevant cohort data should validate our computational approach.

International consensus statement on allergy and rhinology: Allergic rhinitis - 2023

BACKGROUND

In the 5 years that have passed since the publication of the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR-Allergic Rhinitis 2018), the literature has expanded substantially. The ICAR-Allergic Rhinitis 2023 update presents 144 individual topics on allergic rhinitis (AR), expanded by over 40 topics from the 2018 document. Originally presented topics from 2018 have also been reviewed and updated. The executive summary highlights key evidence-based findings and recommendation from the full document.

METHODS

ICAR-Allergic Rhinitis 2023 employed established evidence-based review with recommendation (EBRR) methodology to individually evaluate each topic. Stepwise iterative peer review and consensus was performed for each topic. The final document was then collated and includes the results of this work.

RESULTS

ICAR-Allergic Rhinitis 2023 includes 10 major content areas and 144 individual topics related to AR. For a substantial proportion of topics included, an aggregate grade of evidence is presented, which is determined by collating the levels of evidence for each available study identified in the literature. For topics in which a diagnostic or therapeutic intervention is considered, a recommendation summary is presented, which considers the aggregate grade of evidence, benefit, harm, and cost.

CONCLUSION

The ICAR-Allergic Rhinitis 2023 update provides a comprehensive evaluation of AR and the currently available evidence. It is this evidence that contributes to our current knowledge base and recommendations for patient evaluation and treatment.

Past, present, and future of anti-IgE biologics

About 20 years after the identification of immunoglobulin E (IgE) and its key role in allergic hypersensitivity reactions against normally harmless substances, scientists have started inventing strategies to block its pathophysiological activity in 1986. The initial concept of specific IgE targeting through the use of anti-IgE antibodies has gained a lot of momentum and within a few years independent research groups have reported successful generation of first murine monoclonal anti-IgE antibodies. Subsequent generation of optimized chimeric and humanized versions of these antibodies has paved the way for the development of therapeutic anti-IgE biologicals as we know them today. With omalizumab, there is currently still only one therapeutic anti-IgE antibody approved for the treatment of allergic conditions. Since its application is limited to the treatment of moderate-to-severe persistent asthma and chronic spontaneous urticaria, major efforts have been undertaken to develop alternative anti-IgE biologicals that could potentially be used in a broader spectrum of allergic diseases. Several new drug candidates have been generated and are currently assessed in pre-clinical studies or clinical trials. In this review, we highlight the molecular properties of past and present anti-IgE biologicals and suggest concepts that might improve treatment efficacy of future drug candidates.

CD23 expression on switched memory B cells bridges T-B cell interaction in allergic rhinitis

BACKGROUND

The contribution of B-cell subsets and T-B cell interaction to the pathogenesis of allergic rhinitis (AR) and mechanisms of allergen immunotherapy (AIT) remain poorly understood. This study aimed to outline circulating B-cell signature, the underlying mechanism, and its association with clinical response to AIT in patients with AR.

METHODS

IgD/CD27 and CD24/CD38 core gating systems were used to determine frequencies and phenotypes of B cells. Correlations between B cells, T cells, antigen-specific IgE, and disease severity in AR patients were investigated. Switched memory B cells were co-cultured with type 2 follicular helper T (Tfh2) cells and follicular regulatory T (Tfr) cells. Associations between B-cell subsets and clinical benefits of AIT were analyzed.

RESULTS

Frequencies and absolute numbers of circulating memory B cells were increased in AR patients. CD23 expression on CD19⁺ CD20⁺ CD27⁺ IgD^- switched memory B cells was significantly enhanced and positively correlated with antigen-specific IgE levels, symptom scores, and Tfh2/Tfr cell ratio in AR patients. Compared with those from healthy controls, Tfh2 cells from AR patients had a greater capacity to induce CD23 expression on switched memory B cells via IL-4, which was unable to be sufficiently suppressed by AR-associated Tfr cells with defective IL-10 expression. CD23 expression on switched memory B cells was downregulated after 12-month AIT, which positively associated with disease remission in AR patients.

CONCLUSION

T-B cell interaction, bridged by CD23 expression particularly on switched memory B cells, may be involved in the disease pathogenesis and mechanism of AIT in patients with AR.

Effect of monoclonal antibody drug therapy on mucosal biomarkers in airway disease: A systematic review

BACKGROUND

Monoclonal antibody therapies have a growing role in treating refractory airway disease.

OBJECTIVE

The review aimed to summarize the response of respiratory mucosa to monoclonal antibody treatments in inflammatory airway conditions.

DESIGN

We conducted a systematic review including risk of bias assessment.

DATA SOURCES

MEDLINE, EMBASE and PubMed from 1 January 2000 to 16 November 2019 were searched.

ELIGIBILITY CRITERIA

Eligible studies assessed the immunological and histological response of airway mucosa to monoclonal antibody therapy compared with baseline or a comparison group in patients with respiratory diseases (asthma, chronic rhinosinusitis and allergic rhinitis). Any prospective interventional studies, including randomized controlled trials (RCTs) and single-arm trials, were eligible.

RESULTS

There were 4195 articles screened, and full-text analysis produced n = 11 studies with extractable data. Nine were RCTs, and two were single-arm trials. These studies focused on asthma (n = 9 articles), chronic rhinosinusitis (n = 1) and allergic rhinitis (n = 1). Five monoclonal antibody drugs were assessed (omalizumab, mepolizumab, dupilumab, benralizumab and tralokinumab). Risk of bias was low (n = 6) or unclear (n = 3) in the RCTs and moderate in the single-arm trials. Omalizumab reduced the mucosal concentration of its target, IgE. Dupilumab reduced the concentration of one of its targets, IL-13, but not IL-4. Omalizumab, mepolizumab and benralizumab reduced tissue eosinophil cell density. Dupilumab decreased mucosal eosinophil granule proteins. Tralokinumab did not affect airway mucosa.

CONCLUSIONS

Knowledge of the expected biological response of monoclonal antibody therapy on biomarkers in disease tissue provides an important supplement to data about clinical outcomes. An understanding of the biological effect is essential to identify likely responders, reasons for treatment failure and necessary adjustments to monoclonal antibody treatment. Further investigation into the effect of monoclonal antibody therapy on disease mucosa and more precise endotyping are required to move closer to achieving personalized medicine.

Anti-IgE treatment in allergic rhinitis

OBJECTIVES

To review the efficacy of anti-IgE therapy in allergic rhinitis (AR).

METHODS

Literature search was performed using the PubMed and Proquest Central databases at Kırıkkale University Library.

RESULTS

Although the skin prick testing in patients suffering from AR is positive (indicating that antigen-specific Immunoglobulin E has been produced), there is no association with overall circulating IgE levels. Correlation was lacking between circulating IgE level and either skin prick tests or laboratory testing for specific IgE. Omalizumab binds to uncomplexed IgE in man more avidly than does Fc-epsilon. The effect of omalizumab is to lower the level of IgE and downgrade production of FceRI receptors (which bind IgE) in mast cells and basophils, causing less mast cell recruitment and responsivity and thus diminishing eosinophilic infiltration and activation. Anti-IgE therapy through omalizumab may shorten the lifetime of mast cells and causes dendritic cells to downgrade their production of FcεRI. There are reports indicating benefit from omalizumab in managing food allergies, nasal polyp formation, essential anaphylaxis, AR, venom allergy and eczema. Omalizumab acts to lessen circulating IgE levels, whilst reducing production of FceRI by mast cells and basophils. The fact that omalizumab influences how eosinophils respond may be down to disruption of the antigen-IgE-mast cell interactions, with mast cells being recruited at lower levels and thus chemotactic eosinophilic recruitment via cytokines being greatly reduced. Omalizumab has the effect in cases of perennial AR of blocking the increased eosinophilic recruitment and tissue infiltration initiated by seasonal antigens. Likewise, in omalizumab-treated cases, circulating unbound IgE levels showed significant decreases. For patients with perennial AR, the average daily nasal severity score was significantly reduced where omalizumab was administered, compared to placebo.

CONCLUSION

Omalizumab has efficacy in ameliorating symptoms and reduces the necessity for additional medication in both seasonal and perennial allergic rhinitis.

Clinical Efficacy and Safety of Omalizumab in the Treatment of Allergic Rhinitis: A Systematic Review and Meta-analysis of Randomized Clinical Trials

Background

Patients with moderate to severe allergic rhinitis (AR) who are treated according to the current rhinitis management guidelines may be inadequately controlled. These patients are at risk of serious comorbidities, such as asthma and chronic sinusitis. These symptoms, sneezing and an itchy, runny, stuffy nose, may have a negative impact on patients’ daily functioning. Omalizumab is being developed as a new choice for the treatment of AR. We therefore undertook a meta-analysis to assess the efficacy and safety of omalizumab in the treatment of AR.

Methods

We systematically searched PubMed, Cochrane Library, and MEDLINE databases for randomized controlled studies on the treatment of AR with omalizumab. Our evaluation outcomes were symptom scores, medication efficacy, combined symptom and medication scores, and adverse events. We descriptively summarized and quantitatively synthesized original data to evaluate the efficacy and safety of omalizumab in the treatment of AR by using Stata12.0 software for meta-analyses.

Results

The results of our meta-analysis showed that there were statistically significant differences between the omalizumab group and the control group in the following aspects: daily nasal symptom score (standardized mean difference [SMD] = –0.443, 95% confidence interval [CI]: –0.538 to –0.347, P < .001); daily ocular symptom score (SMD = –0.385, 95% CI: –0.5 to –0.269, P < .001); daily nasal medication symptom scores (SMD = –0.421, 95% CI: –0.591 to –0.251, P < .001); proportion of days of emergency drug use (risk ratio [RR] = 0.488, 95% CI: 0.307 to 0.788, P < .005); rhinoconjunctivitis-specific quality of life questionnaire (SMD = –0.286, 95% CI: –0.418 to –0.154, P < .001); and overall evaluation (RR = 1.435, 95% CI: 1.303–1.582, P < .001). There was no statistically significant difference in safety indicator: adverse events (RR = 1.026, 95% CI: 0.916–1.150, P = .655).

Conclusion

Omalizumab is effective and relatively safe in patients with AR; omalizumab used in conjunction with special immunotherapy has shown promising results, especially in reducing adverse events.

Association of upper and lower airway eosinophilic inflammation with response to omalizumab in patients with severe asthma

Background: The anti-immunoglobulin E monoclonal antibody, omalizumab, is used to treat severe asthma and has the potential to ameliorate airway inflammation. However, the effect of omalizumab in ameliorating upper airway inflammation has not been fully elucidated. Objective: We investigated the association of upper and lower airway inflammation with the response to omalizumab treatment. Methods: We used the Global Evaluation of Treatment Effectiveness to assess the efficacy of omalizumab in treating 16 patients with severe asthma. We also investigated the symptom score, short-acting β-agonist inhaler use, pulmonary function, biomarkers, computed tomography scans, and nasal mucosa pathology at omalizumab initiation and after four months of treatment. Results: When the fraction of exhaled nitric oxide (FeNO) and the percentage of sputum eosinophil were used as indicators of lower airway inflammation, positive correlations were found between CD20 B-cell, mast cell, and eosinophil counts in the nasal mucosa. Improved asthma symptoms were observed in 12 of the 16 severe asthma cases. The FeNO and eosinophil levels in the nasal tissue, prior to the administration of omalizumab were predictors of the response to asthma treatment. Conclusions: These findings suggest heterogeneity among people with severe asthma. In addition, the phenotype associated with response to omalizumab, leading to improvement in asthma symptoms, comprises upper airway eosinophilia and high FeNO levels.

The Role of Anti-IgE Immunoglobulin Therapy in Nasal Polyposis: A Pilot Study

Background

Although the etiology of nasal polyposis (NP) remains unknown, emerging evidence showing elevated local IgE levels and eosinophilic infiltration suggests an allergic etiology. Given this evidence, this pilot study examined whether anti-IgE therapy is efficacious in the treatment of NP.

Methods

Data were retrospectively collected on two groups of patients with atopic asthma and NP who underwent endoscopic sinus surgery (ESS), including a control group (n = 4) and an anti-IgE treatment group (n = 4), who received the anti-IgE agent, omalizumab, postoperatively. Both groups were evaluated by sinus computed tomography (CT) and nasal endoscopic examination, and comparisons were made between the groups with respect to differences in the recurrence of NP after ESS.

Results

Collectively, the subjects showed a direct relationship between NP severity and pretreatment total serum IgE levels. Preoperatively, there were no differences between the groups with regard to their total serum IgE levels, sinus CT scores, and endoscopically determined NP scores. Relative to corresponding preoperative values, there was no significant improvement in the sinus CT scores in either treatment group postoperatively. In contrast, relative to preoperative values, the nasal polyp scores significantly improved in the anti-IgE group, whereas the control group showed no significant improvement.

Conclusion

This pilot study provides new evidence establishing that (1) endoscopic NP severity directly correlates to total serum IgE levels and (2) inclusion of anti-IgE therapy in the postpolypectomy management of atopic asthmatic individuals may reduce the severity of NP recurrence.

International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis

BACKGROUND

Critical examination of the quality and validity of available allergic rhinitis (AR) literature is necessary to improve understanding and to appropriately translate this knowledge to clinical care of the AR patient. To evaluate the existing AR literature, international multidisciplinary experts with an interest in AR have produced the International Consensus statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR).

METHODS

Using previously described methodology, specific topics were developed relating to AR. Each topic was assigned a literature review, evidence-based review (EBR), or evidence-based review with recommendations (EBRR) format as dictated by available evidence and purpose within the ICAR:AR document. Following iterative reviews of each topic, the ICAR:AR document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:AR document addresses over 100 individual topics related to AR, including diagnosis, pathophysiology, epidemiology, disease burden, risk factors for the development of AR, allergy testing modalities, treatment, and other conditions/comorbidities associated with AR.

CONCLUSION

This critical review of the AR literature has identified several strengths; providers can be confident that treatment decisions are supported by rigorous studies. However, there are also substantial gaps in the AR literature. These knowledge gaps should be viewed as opportunities for improvement, as often the things that we teach and the medicine that we practice are not based on the best quality evidence. This document aims to highlight the strengths and weaknesses of the AR literature to identify areas for future AR research and improved understanding.

Treating Moderate-to-Severe Allergic Asthma with a Recombinant Humanized Anti-IgE Monoclonal Antibody (Omalizumab)

Bronchial asthma is a chronic inflammatory disease of the airways which is recognized as a highly prevalent health problem in both the developed and the developing world, with significant human and economic consequences.Allergy is acknowledged as a major risk factor for asthma. The pathogenetic aspects of allergic asthma are characterized by airway inflammation with infiltration of mast cells, basophils, eosinophils, monocytes and T helper type 2 lymphocytes, along with the isotype switching of B cells to generate immunoglobulins of the immunoglobulin E (IgE) class. Increased asthma severity is not only associated with recurrent hospitalization and increased mortality but also with higher social costs.Inhaled corticosteroids are the standard anti-inflammatory medication and are effective for most asthma patients, but there is a substantial number of asthmatics who remain symptomatic even after receiving treatment with inhaled corticosteroids and long-acting beta(2)-adrenoceptor agonists (beta(2)-agonists), and sometimes are in need of systemic corticosteroids to control the disease. These patients account for about 50% of the healthcare costs of asthma.New treatment options more specifically targeting the pathophysiologic events causing development of asthma are therefore required in these patients.A novel therapeutic approach to asthma and other allergic respiratory diseases involves interference with the action of IgE and prevention of subsequent IgE-mediated responses.Omalizumab is a humanized recombinant monoclonal anti-IgE antibody developed for the treatment of allergic diseases, with clear efficacy in adolescent and adult patients with moderate-to-severe allergic asthma. This non-anaphylactogenic anti-IgE antibody inhibits IgE functions by blocking free serum IgE and inhibiting their binding to cellular receptors. Omalizumab therapy is well tolerated and significantly improves symptoms and disease control, and reduces asthma exacerbations and the need to use high dosages of inhaled corticosteroids. Moreover, omalizumab improves quality of life of patients with severe persistent allergic asthma that is inadequately controlled by currently available asthma medications. In conclusion, omalizumab may fulfill an important need in patients with moderate-to-severe asthma inadequately controlled with inhaled corticosteroids +beta(2)-agonists.

A pilot study of omalizumab in eosinophilic esophagitis

Eosinophilic disorders of the gastrointestinal tract are an emerging subset of immune pathologies within the spectrum of allergic inflammation. Eosinophilic Esophagitis (EoE), once considered a rare disease, is increasing in incidence, with a rate of over 1 in 10,000 in the US, for unknown reasons. The clinical management of EoE is challenging, thus there is an urgent need for understanding the etiology and pathophysiology of this eosinophilic disease to develop better therapeutic approaches. In this open label, single arm, unblinded study, we evaluated the effects of an anti-IgE treatment, omalizumab, on local inflammation in the esophagus and clinical correlates in patients with EoE. Omalizumab was administered for 12 weeks to 15 subjects with long standing EoE. There were no serious side effects from the treatment. Esophageal tissue inflammation was assessed both before and after therapy. After 3 months on omalizumab, although tissue Immunoglobulin E (IgE) levels were significantly reduced in all but two of the subjects, we found that full remission of EoE, which is defined as histologic and clinical improvement only in 33% of the patients. The decrease in tryptase-positive cells and eosinophils correlated significantly with the clinical outcome as measured by improvement in endoscopy and symptom scores, respectively. Omalizumab-induced remission of EoE was limited to subjects with low peripheral blood absolute eosinophil counts. These findings demonstrate that in a subset of EoE patients, IgE plays a role in the pathophysiology of the disease and that anti-IgE therapy with omalizumab may result in disease remission. Since this study is open label there is the potential for bias, hence the need for a larger double blind placebo controlled study. The data presented in this pilot study provides a foundation for proper patient selection to maximize clinical efficacy.

Novel targeted therapies for eosinophil-associated diseases and allergy

Eosinophil-associated diseases often present with life-threatening manifestations and/or chronic organ damage. Currently available therapeutic options are limited to a few drugs that often have to be prescribed on a lifelong basis to keep eosinophil counts under control. In the past 10 years, treatment options and outcomes in patients with clonal eosinophilic and other eosinophilic disorders have improved substantially. Several new targeted therapies have emerged, addressing different aspects of eosinophil expansion and inflammation. In this review, we discuss available and currently tested agents as well as new strategies and drug targets relevant to both primary and secondary eosinophilic diseases, including allergic disorders.

Unraveling the significance of IgE autoantibodies in organ-specific autoimmunity: lessons learned from bullous pemphigoid

Bullous pemphigoid (BP), a cutaneous autoimmune blistering disease, has provided a useful model to elucidate a role for IgE in autoimmunity. IgE antibodies specific for the BP180 autoantigen are detected in sera and biopsy samples from the majority of BP patients. In BP biopsies, both IgE and BP180 antigen localize to the surface of mast cells, and incubation of circulating basophils from these patients with BP180 protein triggered degranulation. The in vivo pathogenicity of BP180-specific IgE was confirmed in mouse models, where injection of purified BP IgE into human skin grafted onto nu/nu mice replicated the early phase of lesion development, including mast cell degranulation, eosinophil infiltration and development of urticarial plaques. In addition, IgE antibodies from patient sera bind to BP180 on basal keratinocytes, resulting in internalization of BP180, production of inflammatory cytokines, IL-6 and IL-8, and a decrease in the number of hemidesmosomes at the basement membrane zone. These findings have led to therapeutic trials of the anti-IgE monoclonal antibody omalizumab in BP, resulting in substantial improvement in the patients' disease. Overall, the work in BP provides the first evidence for a pathogenic role for IgE in autoimmunity.

Treating severe allergic asthma with anti-IgE monoclonal antibody (omalizumab): a review

Increased asthma severity is not only associated with enhanced recurrent hospitalization and mortality but also with higher social costs. Several cases of asthma are atopic in nature, with the trigger for acute asthma attacks and chronic worsening of inflammation being allergens inducing an immune, IgE mediated response. Anti-inflammatory treatments are effective for most of asthma patients, but there are subjects whose disease is incompletely controlled by inhaled or systemic corticosteroids and these patients account for about 50% of the healthcare costs of asthma. Omalizumab is a biological engineered, humanized recombinant monoclonal anti-IgE antibody developed for the treatment of allergic diseases and with clear efficacy in adolescent and adult patients with severe allergic asthma. The anti-IgE antibody inhibits IgE functions blocking free serum IgE and inhibiting their binding to cellular receptors. By reducing serum IgE levels and IgE receptor expression on inflammatory cells in the context of allergic cascade, omalizumab has demonstrated to be a very useful treatment of atopic asthma, improving quality of life of patients with severe persistent allergic asthma that is inadequately controlled by currently available asthma medications. Several trials have demonstrated that this therapy is well tolerated and significantly improves symptoms and disease control, reducing asthma exacerbations and the need to use high dosage of inhaled corticosteroids.

Clinical characteristics of angioedema with eosinophilia

Angioedema with eosinophilia (AE) is a very rare allergy disease, case reports of which have been published sporadically since 1984. Here, we retrospectively analyzed the clinical features of 10 AE patients in Korea. Nine of the 10 subjects were young females, ranging from 23 to 38 years old. Twenty percent of the subjects had episodic-type AE with high serum IgM and eosinophil counts, while 80% were non-episodic type with normal serum IgM levels but high eosinophil counts. All patients had used systemic corticosteroids to control AE. One patient with refractory episodic-type AE was treated with anti-IgE antibody. This is the first study to evaluate the clinical characteristics of AE in a Korean population.

Omalizumab may decrease IgE synthesis by targeting membrane IgE+ human B cells

Background

Omalizumab, is a humanized anti-IgE monoclonal antibody used to treat allergic asthma. Decreased serum IgE levels, lower eosinophil and B cell counts have been noted as a result of treatment. In vitro studies and animal models support the hypothesis that omalizumab inhibits IgE synthesis by B cells and causes elimination of IgE-expressing cells either by induction of apoptosis or induction of anergy or tolerance.

Methods

We examined the influence of omalizumab on human tonsillar B cell survival and on the genes involved in IgE synthesis. Tonsillar B cells were stimulated with IL-4 plus anti-CD40 antibody to induce class switch recombination to IgE production in the presence or absence of omalizumab. Cell viability was assessed and RNA extracted to examine specific genes involved in IgE synthesis.

Conclusions

We found that omalizumab reduced viable cell numbers but this was not through induction of apoptosis. IL-4R and germline Cϵ mRNA levels were decreased as well as the number of membrane IgE+ cells in B cells treated with omalizumab. These data suggest that omalizumab may decrease IgE synthesis by human B cells by specifically targeting membrane IgE-bearing B cells and inducing a state of anergy.

Existence of antigen-specific immunoglobulin E is not sufficient for allergic nasal eosinophil infiltration in mice

BACKGROUND

Immunoglobulin E (IgE) is important for the development of allergic rhinitis (AR), though the contribution of IgE to the infiltration of eosinophils in the nasal mucosa has not been fully elucidated. In this study, antigen-induced sneezing and nasal eosinophil accumulation were comparatively investigated in anti-ovalbumin (OVA)-IgE transgenic (Tg) and wild-type (WT) mice.

METHODS

Tg and OVA-immunized WT mice were intranasally challenged with OVA. Antigen-specific serum IgE level, sneezing and infiltration of eosinophil into the nasal cavity were then examined.

RESULTS

The level of serum OVA-specific IgE in Tg mice was significantly higher than that in antigen-immunized WT mice. Compared to saline challenge, intranasal challenge with OVA significantly induced sneezing in both Tg and immunized WT mice. However, antigen-induced nasal eosinophil infiltration was observed in immunized WT mice but not in Tg mice.

CONCLUSIONS

IgE-mediated responses might not play a crucial role in antigen-induced eosinophil infiltration in AR.

Anti-immunoglobulin e therapy

The importance of immunoglobulin E (IgE) in atopic disorders such as asthma, allergic rhinitis, food allergies, and atopic dermatitis is well established. Elevation of total serum IgE is typically found in many atopic patients, and in predisposed individuals, allergen-specific IgE is produced. The availability of humanized monoclonal antibodies against IgE has provided a new therapeutic option and tool to explore the role IgE in allergic diseases and the effects of inhibiting IgE itself. Omalizumab is a humanized, monoclonal antibody that recognizes and binds to the Fc portion of the IgE molecule. Administration of omalizumab results in a rapid and substantial decrease in free IgE in serum. Consequently, the activity of cell populations involved in allergic inflammation, including mast cells, eosinophils, basophils, and antigen-presenting cells, is affected as well. Clinically, anti-IgE therapy has already been proven to be useful in the treatment of asthma and allergic rhinitis. The aim of this review is to provide an overview of the mechanisms of action of anti-IgE therapy as well as its efficacy in the treatment of allergic diseases, especially asthma. Considerations regarding dosing and safety of omalizumab will be addressed as well.

Successful treatment of chronic eosinophilic pneumonia with anti-IgE therapy

Anti-IgE therapy, using recombinant humanized anti-IgE antibodies, is clinically effective in patients with eosinophil-related disorders such as allergic asthma, allergic rhinitis, and chronic urticaria. Chronic eosinophilic pneumonia tends to respond promptly to systemic corticosteroid therapy, however; relapses are common following corticosteroid tapering. We treated two patients (17- and 19-yr-old males) of chronic eosinophilic pneumonia whose symptoms were cough and dyspnea on exertion. The symptoms were recurrent while tapering off corticosteroid. They were treated with anti-IgE antibody without recurrence for 2 yr and 15 months. Here, we first describe clinical experience of the 2 cases of chronic eosinophilic pneumonia.

Clinical efficacy of anti-IgE therapy for eosinophilic otitis media

OBJECTIVE

Eosinophilic otitis media (EOM) is an intractable otitis media characterized by a highly viscous effusion containing eosinophils, and high levels of immunoglobulin (Ig) E are detected in the middle ear effusion (MEE). We carried out a pilot study to determine whether anti-IgE therapy is efficacious in the treatment of EOM.

STUDY DESIGN

Prospective study.

SETTING

Tertiary referral center.

PATIENTS AND METHODS

Eight patients with EOM received the anti-IgE agent omalizumab for at least 3 months, in addition to ordinary treatments for EOM. They were evaluated by a questionnaire for ear and respiratory symptoms, clinical scores, surrogate markers in the blood, and hearing acuity before and after the anti-IgE therapy. Nine EOM patients without anti-IgE therapy were included as controls.

RESULTS

The ear symptom scores and clinical scores gradually decreased during the therapy. In particular, 5 patients who were treated for more than 1 year showed improvement of their clinical scores with resolution of the MEE. The total serum IgE level was significantly elevated after 3 months of therapy (p < 0.01). Deterioration of the bone conduction hearing levels was more frequently found in the control group than in the omalizumab group.

CONCLUSION

This pilot study provides new evidence establishing that long-term anti-IgE therapy improved the clinical ear symptoms of EOM and bone conduction hearing levels were mostly preserved. Therefore, long-term anti-IgE therapy can be effective for EOM to inhibit eosinophilic inflammation in the middle ear.

Allergic rhinitis: an update on disease, present treatments and future prospects

Allergic rhinitis (AR) is an inflammation of nasal mucosa mediated by IgE-associated processes occurring independently, or concurrently with asthma. AR is characterized by sensitization-formation and expression of antigen specific IgE, followed by inflammation in two phases. The early phase response involves cross linking of IgE molecules leading to degranulation of mast cells and release of preformed mediators such as histamine and tryptase, or newly synthesized mediators such as prostaglandins and leukotrienes. The late phase response is predominated by the presence of eosinophils, lymphocytes, cytokines, and adhesion molecules. Newer insights reveal that the whole phenomenon of immunological inflammation is intricately knit with neural pathways, which strongly influence the process. Furthermore, AR can impact psychological health and vice versa. Classical pharmacotherapy of AR includes use of oral or topical antihistamines, oral antileukotrienes, topical corticosteroids, mast cell stabilizers, decongestants, and an anticholinergic agent. Among immunomodulatory treatments, immunotherapy is gaining widespread use, while antibody treatment is restricted mainly to resistant cases. Several small molecules with improved safety profile, or targeting novel mechanisms are in the clinical research. Newer antihistamines and corticosteroids with improved safety profile and antagonists of the prostaglandin D(2) (CRTH2) receptors are likely to be available for clinical use in the near future. Lack of properly validated animal models and complexities associated with clinical evaluation are some of the challenges facing the researchers in AR. Comprehensive understanding of immunological and neurological processes in AR would facilitate the future quest for more effective and safer management of this disease.

Therapy with omalizumab for patients with severe allergic asthma improves asthma control and reduces overall healthcare costs

BACKGROUND

Patients with asthma who have persistent symptoms despite treatment with inhaled steroids and long-acting beta agonists are considered to have severe asthma. Omalizumab is a monoclonal antibody directed against IgE, which is used as an add-on treatment for patients who have severe persistent allergic asthma.

AIMS

The aim of this study was to assess the clinical benefit and healthcare utilisation of patients who responded to omalizumab therapy and to establish an overall cost implication.

METHODS

This was an observational retrospective cohort study designed to investigate the effect of omalizumab on exacerbations of asthma before and after 6 months of treatment in Irish patients.

RESULTS

Centres who had treated patients with severe allergic asthma for the 6 months prior and post omalizumab treatment were audited with a standardised assessment tool. Sixty-three (32 male) patients were studied. In the 6 months prior to omalizumab 41 of 63 (66%) had been hospitalised, and this fell to 15 of 63 (24%), p < 0.0001 in the 6 months after treatment was started. Hospital admissions reduced from 2.4 ± 0.41 to 0.8 ± 0.37 and the mean number of bed days occupied was reduced from 16.6 ± 2.94 to 5.3 ± 2.57 days, p < 0.001. The number of oral corticosteroid doses used fell from 3.1 ± 0.27 to 1.2 ± 0.17, p < 0.001. The overall cost saving per omalizumab responder patients for 6 months was <euro>834.

CONCLUSIONS

Six months therapy with omalizumab reduced the number of bed days, the number of hospitalisations and the use of oral corticosteroids compared to the 6 months prior to commencement. Despite the cost of the additional therapy there were overall savings in health costs.

Effects of pharmacological and non-pharmacological interventions

BACKGROUND

Asthma is recognised as a condition with variable airway obstruction with pathophysiological features that include activation of a wide range of inflammatory and structural cells. Additionally, structural changes in the airways have been demonstrated. This includes increased thickening of components in the basement membrane region, increased smooth muscle mass, increased vascularisation and many other events that is often referred to as remodelling of the airways. These processes and the underlying mechanisms have attracted considerable attention.

METHODS AND RESULTS

This review describes the different interventive approaches that have been tried in order to improve asthma control and affect the underlying pathophysiological pathways. These include elimination of harmful environmental and occupational exposures, a wide range of pharmacological agents as well as bronchial thermoplasty. The existing evidence for effects on airway inflammation and airway remodelling is discussed in relationship to mechanistic aspects and short- and long-term outcome.

CONCLUSION

It is expected that modulation of the asthmatic airway remodelling will become an even more important endpoint in the near future.

The pathophysiology, diagnosis and treatment of allergic rhinitis

Treatment of AR requires a stepwise approach depending on the severity and duration of symptoms. Treatment options for AR consist of allergen avoidance, pharmacotherapy, immunotherapy and surgery. For the mechanisms of AR, anti-IgE antibody and specific antibody to cytokines such as IL-4 or IL-5 that correlate with allergic inflammation have recently emerged. SLIT is currently widely used due to its efficacy, safety and convenience, which replaces subcutaneous immunotherapy. Although allergen avoidance and immunotherapy are theoretically ideal, antihistamines and intranasal corticosteroids will play the main role in the management of AR until an innovative treatment develops. However, patients' main symptom, the duration and severity of AR, patients' compliance, safety of medication and cost-effectiveness should be considered when treatment options are chosen. In conclusion, physicians should be aware of etiology, pathophysiology, symptoms, signs and diseases related to AR in order to make a correct diagnosis and choose a proper treatment option for each patient.

Effects of omalizumab on markers of inflammation in patients with allergic asthma

Asthma is a chronic inflammatory disease of the airways in which immunoglobulin E (IgE) plays a key role by activating a variety of inflammatory cells through interactions with FcepsilonRI and FcepsilonRII receptors. The role of IgE in allergic inflammation provided the rationale for developing omalizumab, a humanized monoclonal anti-IgE antibody, for patients with moderate-to-severe or severe allergic asthma. The reductions in circulating levels of IgE resulting from omalizumab treatment leads to reductions in FcepsilonRI expression on mast cells, basophils and dendritic cells. This combined effect results in attenuation of several markers of inflammation, including peripheral and bronchial tissue eosinophilia and levels of granulocyte macrophage colony stimulating factor, interleukin (IL)-2, IL-4, IL-5 and IL-13. By blocking IgE binding to its receptors and diminishing dendritic cell FcepsilonRI receptor expression, omalizumab may also reduce allergen presentation to T cells and the production of Th2 cytokines. The anti-inflammatory effects of omalizumab may, therefore, explain the reductions in asthma exacerbations and symptoms seen in clinical trials in patients with moderate-to-severe or severe, persistent, inadequately controlled allergic asthma.

Effect of omalizumab on peripheral blood eosinophilia in allergic asthma

Eosinophilia is an established marker of asthma-related inflammation. We assessed the effect of omalizumab on peripheral blood eosinophil counts using a pooled analysis of data from five randomized, double-blind, placebo-controlled studies in patients with moderate-to-severe persistent allergic asthma receiving moderate-to-high-dose inhaled corticosteroids (omalizumab, n=1136; placebo, n=1100). Relationships between omalizumab, peripheral blood eosinophils, serum free IgE concentrations and clinical outcomes were explored. Baseline mean eosinophil counts were similar in each treatment group. Post-treatment eosinophil counts were significantly reduced from baseline in the omalizumab group (p<0.0001) but were not significantly different in the placebo group. Greater reductions in eosinophil counts were observed in patients who had post-treatment free IgE levels <50ng/mL. Three studies included steroid-stable and steroid-reduction phases. At the end of each phase in these studies, a significantly greater reduction in eosinophil counts was achieved in the omalizumab group compared with the placebo group (p<0.0001). A consistent pattern of improved clinical outcomes/decreased eosinophils and worsened clinical outcomes/increased eosinophils was observed for both omalizumab and placebo treatment groups. The findings from our analysis of a large patient population are consistent with earlier reports of the inhibitory effect of omalizumab on eosinophils.

Eosinophils in bronchial mucosa of asthmatics after allergen challenge: effect of anti-IgE treatment

BACKGROUND

Anti-IgE, omalizumab, inhibits the allergen response in patients with asthma. This has not been directly related to changes in inflammatory conditions. We hypothesized that anti-IgE exerts its effects by reducing airway inflammation. To that end, the effect of anti-IgE on allergen-induced inflammation in bronchial biopsies in 25 patients with asthma was investigated in a randomized, double-blind, placebo-controlled study.

METHODS

Allergen challenge followed by a bronchoscopy at 24 h was performed at baseline and after 12 weeks of treatment with anti-IgE or placebo. Provocative concentration that causes a 20% fall in forced expiratory volume in 1 s (PC(20)) methacholine and induced sputum was performed at baseline, 8 and 12 weeks of treatment. Changes in the early and late responses to allergen, PC(20), inflammatory cells in biopsies and sputum were assessed.

RESULTS

Both the early and late asthmatic responses were suppressed to 15.3% and 4.7% following anti-IgE treatment as compared with placebo (P < 0.002). This was paralleled by a decrease in eosinophil counts in sputum (4-0.5%) and postallergen biopsies (15-2 cells/0.1 mm(2)) (P < 0.03). Furthermore, biopsy IgE+ cells were significantly reduced between both the groups, whereas high-affinity IgE receptor and CD4+ cells were decreased within the anti-IgE group. There were no significant differences for PC(20) methacholine.

CONCLUSION

The response to inhaled allergen in asthma is diminished by anti-IgE, which in bronchial mucosa is paralleled by a reduction in eosinophils and a decline in IgE-bearing cells postallergen without changing PC(20) methacholine. This suggests that the benefits of anti-IgE in asthma may be explained by a decrease in eosinophilic inflammation and IgE-bearing cells.

Specific IgE serum concentration is associated with symptom severity in children with seasonal allergic rhinitis

BACKGROUND

The impact of allergen-specific and total IgE serum levels before and during the pollen season on symptom severity as well as efficacy of treatment with anti-IgE requires further delineation.

METHODS

Birch and grass pollen allergic patients aged 6-17 years with seasonal allergic rhinitis (SAR) were analyzed for the association of IgE serum concentration with symptom severity and rescue medication use (combination: symptom load, SL) during the grass pollen season. Reference group A (n = 53) received placebo, while group B (n = 54) received Omalizumab (anti-IgE) monotherapy before and during the grass pollen season.

RESULTS

Patients on placebo with high baseline specific grass pollen IgE (>50 kU/l) had a significantly higher SL compared with those with low IgE levels (< or =50 kU/l): SL 1.28 vs 0.61, P = 0.015. This association was nonexistent in patients treated with anti-IgE. In contrast, baseline total IgE levels did not correlate with SL in any group. Patients with anti-IgE treatment and high free total IgE levels (>16.7 ng/ml) had a significantly higher SL compared with those with low free total IgE levels (< or =16.7 ng/ml): SL 0.63 vs 0.23, P = 0.031.

CONCLUSIONS

Baseline specific IgE, but not total IgE, is associated with symptom severity during the pollen season in children with SAR. Likewise, the symptom load in SAR patients with anti-IgE correlates with free total IgE levels. Although further research in larger populations is needed to confirm our findings, our data suggest that specific IgE can be used as a parameter for patient selection for this kind of treatment.

Study of gene-gene interactions for endophenotypic quantitative traits in Chinese asthmatic children

BACKGROUND

Asthma is a complex disease resulting from interactions between multiple genes and environmental factors. Study of gene-gene interactions could provide insight into the pathophysiology of asthma.

METHODS

We investigated the interactions among 18 single-nucleotide polymorphisms in eight candidate genes for plasma total immunoglobulin E (IgE) concentration and peripheral blood (PB) eosinophil count in 298 Chinese asthmatic children and 175 controls. Generalized multifactor dimensionality reduction and generalized linear model were used to analyze gene-gene interactions for the quantitative traits.

RESULTS

A significant interaction was found between R130Q in IL13 and I50V in IL4RA for plasma total IgE concentration, with a cross-validation (CV) consistency of nine of 10 and a prediction error of 41.1% (P = 0.013). Plasma total IgE concentration was significantly higher in the high-risk than the low-risk groups (P < 0.0001). For PB eosinophil count, significant interaction was found between C-431T in TARC and RsaI_in2 in FCERIB, with a CV consistency of nine of 10 and a prediction error of 40.2% (P = 0.009). PB eosinophil count was significantly higher in the high-risk group than the low-risk groups (P < 0.0001). Generalized linear model also revealed significant gene-gene interaction for the above two endophenotypes with P = 0.013 for plasma total IgE concentration and P = 0.029 for PB eosinophil count respectively.

CONCLUSIONS

Our data suggest significant interactions between IL13 and IL4RA for plasma total IgE concentration, and this is the first report to show significant interaction between TARC and FCERIB for PB eosinophil count in Chinese asthmatic children.

Severe asthma and the omalizumab option

Atopic diseases and asthma are increasing at a remarkable rate on a global scale. It is now well recognized that asthma is a chronic inflammatory disease of the airways. The inflammatory process in many patients is driven by an immunoglobulin E (IgE)-dependent process. Mast cell activation and release of mediators, in response to allergen and IgE, results in a cascade response, culminating in B lymphocyte, T lymphocyte, eosinophil, fibroblast, smooth muscle cell and endothelial activation. This complex cellular interaction, release of cytokines, chemokines and growth factors and inflammatory remodeling of the airways leads to chronic asthma. A subset of patients develops severe airway disease which can be extremely morbid and even fatal. While many treatments are available for asthma, it is still a chronic and incurable disease, characterized by exacerbation, hospitalizations and associated adverse effects of medications. Omalizumab is a new option for chronic asthma that acts by binding to and inhibiting the effects of IgE, thereby interfering with one aspect of the asthma cascade reviewed earlier. This is a humanized monoclonal antibody against IgE that has been shown to have many beneficial effects in asthma. Use of omalizumab may be influenced by the cost of the medication and some reported adverse effects including the rare possibility of anaphylaxis. When used in selected cases and carefully, omalizumab provides a very important tool in disease management. It has been shown to have additional effects in urticaria, angioedema, latex allergy and food allergy, but the data is limited and the indications far from clear. In addition to decreasing exacerbations, it has a steroid sparing role and hence may decrease adverse effects in some patients on high-dose glucocorticoids. Studies have shown improvement in quality of life measures in asthma following the administration of omalizumab, but the effects on pulmonary function are surprisingly small, suggesting a disconnect between pulmonary function, exacerbations and quality of life. Anaphylaxis may occur rarely with this agent and appropriate precautions have been recommended by the Food and Drug Administration (FDA). As currently practiced and as suggested by the new asthma guidelines, this biological agent is indicated in moderate or severe persistent allergic asthma (steps 5 and 6).

New treatment options in allergic rhinitis: patient considerations and the role of ciclesonide

Allergic rhinitis (AR) is a chronic inflammatory respiratory disease affecting 5%-50% of the worldwide population and its prevalence is increasing (Herman 2007). In addition, AR is associated with asthma and other co-morbidities such as conjunctivitis and sinusitis. The main symptoms are nasal congestion, rhinorrea, sneezing, itching, and post-nasal drainage induced after allergen exposure by an IgE-mediated inflammation of the membranes lining the nose. AR is not a life-threatening disease, but it has been shown to have a significant impact on quality of life. The Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines propose a classification of AR in intermittent and persistent, each graded as mild or moderate-severe, and provide a stepwise approach to the treatment. Inhaled steroids and antihistamine are the main tools in AR therapy but more safe and effective drugs are, however, needed. Inhaled steroid ciclesonide appears to be safe and effective.

Immunomodulators for allergic respiratory disorders

New knowledge about the pathogenesis of allergic and immunologic diseases has led to a variety of novel targeted therapeutic approaches. Many immunomodulators are currently under development for the therapy of asthma and allergic and immunologic diseases and are undergoing human clinical trials. The study of immunomodulators in human subjects is ultimately required to determine their therapeutic utility because several agents showing promise in in vitro and animal models have failed in human studies. Novel therapeutic approaches include Toll-like receptor 4 and 9 agonists, immunostimulatory oligodeoxynucleotides, oral and parenterally administered cytokine blockers, and specific cytokine receptor antagonists. Transcription factor modulators targeting syk kinase, peroxisome proliferator-activated receptor gamma, and nuclear factor kappaB are also being evaluated for the treatment of allergic diseases, especially asthma. The anti-IgE mAb omalizumab is already used for the treatment of allergic asthma, but its potential role for other allergic diseases has yet to be clearly defined. Overall, the development of new agents that inhibit specific immunopathogenic mechanisms holds promise for beneficial outcomes for patients with the least amount of risk. However, agents that are too specific in their targets might not exhibit therapeutic benefits because of the redundancy of the immune system and the heterogeneity of diseases such as asthma. The goal of this review is to summarize the data from human clinical trials with immunomodulators, discussing the rationale for their use, efficacy results, and putative adverse events associated with them.

Treatment strategies for allergy and asthma

Allergic diseases have reached epidemic proportions worldwide. An understanding of the cellular and soluble mediators that are involved in allergic inflammatory responses not only helps in understanding the mechanisms of current treatments, but is also important for the identification of new targets that are amenable to both small-molecule and biological interventions. There is now considerable optimism with regards to tackling the allergy epidemic in light of improvements in systemic and mucosal allergen-specific immunotherapy, the identification of key cytokines and their receptors that drive T-helper-2-cell polarization, a clearer understanding of the pathways of leukocyte recruitment and the signalling pathways that are involved in cell activation and mediator secretion, and new approaches to vaccine development.

The role of anti-IgE therapy in combination with allergen specific immunotherapy for seasonal allergic rhinitis

Novel therapies that interfere specifically with immunologic mechanisms underlying allergen-induced pathology are currently in clinical evaluation. Among these is anti-IgE, which directly targets IgE serum antibodies, thus inhibiting the central mechanism of immediate-type hypersensitivity reactions. Application of anti-IgE antibodies effectively reduces IgE serum levels regardless of allergen specificity. Anti-IgE therapy has been successfully tested in patients with allergic rhinitis, asthma, and food allergy, showing significant efficacy in reducing symptom scores and the use of rescue medications. However, such therapy is limited by high costs and the requirements for permanent or every-season treatment. The advantage of specific immunotherapy (SIT) is the potential to alter the course of the disease, which has been demonstrated in patients with allergic rhinitis, insect venom allergy and, to a lesser degree, asthma. The broader application of SIT is restricted by sometimes life-threatening adverse effects. The combination of anti-IgE with SIT was suggested to be superior to each single treatment protocol in children and adolescents with allergic rhinitis. In a randomized, double-blind trial to assess the efficacy and safety of anti-IgE (omalizumab) or placebo in combination with SIT (birch pollen or grass pollen), the combination therapy reduced symptom load, the sum of daily symptom severity score plus rescue medication use, over the birch and grass pollen seasons by nearly 50% over SIT alone. These data show that the combination of anti-IgE plus SIT may be beneficial for the treatment of allergic diseases, offering improved efficacy, limited adverse effects, and potential immune-modifying effects.

Omalizumab is more effective than suplatast tosilate in the treatment of Japanese cedar pollen-induced seasonal allergic rhinitis

BACKGROUND

Seasonal allergic rhinitis (SAR) induced by Japanese cedar pollens is a major problem in Japan. Omalizumab, a humanized monoclonal anti-IgE antibody, improves symptoms associated with SAR, but a comparative study with an anti-allergy drug has not yet been conducted.

OBJECTIVE

To compare the efficacy and safety of omalizumab with suplatast tosilate, a selective T-helper type 2 (Th2) cytokine inhibitor, in patients with Japanese cedar pollen-induced SAR.

METHODS

A randomized, double-blind, double-dummy study was conducted in 308 Japanese patients with a history of moderate-to-severe SAR who showed a CAP-RAST value (> or =2+) specifically to Japanese cedar pollens. Patients were treated for 12 weeks with omalizumab plus placebo of suplatast tosilate or suplatast tosilate plus placebo of omalizumab.

RESULTS

The mean daily nasal symptom medication scores (sum of the daily nasal symptom severity score and daily nasal rescue medication score) were significantly lower in the omalizumab group than in the suplatast tosilate group during three evaluation periods (P<0.001). The omalizumab group also had significantly lower mean daily nasal severity scores, each of the mean daily nasal and ocular symptom severity scores (sneezing, runny nose, stuffy nose, itchy nose, itchy eyes, watery eyes, and red eyes). Omalizumab reduced rescue medication requirements, and the proportion of days with any rescue medication use in the omalizumab group was significantly lower. Serum-free IgE levels markedly decreased in the omalizumab group and it was associated with clinical efficacy. The adverse reaction profiles were similar between the two groups. The overall incidence of injection site reactions was higher in the omalizumab group than in the suplatast tosilate group, but all these events were of mild degree. No anti-omalizumab antibodies were detected.

CONCLUSION

Omalizumab showed significantly greater improvements than suplatast tosilate in the treatment of SAR induced by Japanese cedar pollens.

The impact of comorbid atopic disease on asthma: clinical expression and treatment

Clinically, asthma and allergic rhinitis involve separate regions of the respiratory tract while representing a common underlying inflammatory syndrome. Much evidence supports an epidemiologic association between the diseases, paranasal sinus involvement in both conditions, and parallel relationship in severity and treatment outcomes. Pathophysiologic mechanisms, including immunoglobulin E (IgE)- mediated inflammation, are also shared. Blocking IgE with the recombinant humanized monoclonal antibody omalizumab demonstrated clinical efficacy in patients with upper and lower airway diseases. IgE blockade, leukotriene modulation, and B-cell depletion therapy have all exhibited success in chronic inflammation, reinforcing and expanding the beneficial role of immunomodulation of global mediators.

Anti-IgE and chemotherapy: a critical appraisal of treatment options for severe asthma

In this narrative review the scientific rationale for the development of a therapeutic modality for asthma based on decreasing the circulating and cell-bound levels of immunoglobulin-E (IgE) is outlined. The one drug that has so far entered clinical practice to do this is a humanised monoclonal antibody to the Fc portion of the IgE molecule, omalizumab. It is highly effective in reducing IgE blood levels and its established mode of delivery is by subcutaneous injection. The clinical trial development of omalizumab is reviewed and the published data and claims for its efficacy and role in clinical practice is critically appraised. The target group of omalizumab has become focused on severe asthmatics who are still symptomatic after being administered with high-dose inhaled corticosteroids plus long-acting beta-agonists. The strongest evidence for effect is in those with frequent severe exacerbations.

[Anti-immunoglobulin E, a monoclonal antibody to treat respiratory disorders]

Omalizumab is a monoclonal antibody that interrupts allergic reaction--irrespective of the nature of the allergen--by blocking free immunoglobulin E (IgE). The IgE is thus prevented from attaching to cell receptors and setting in motion an allergic cascade of inflammatory mediators. Other interesting biological effects of omalizumab are that it downregulates IgE receptor expression on cell membranes and reduces bronchial eosinophilic infiltration. Clinical trials have demonstrated omalizumab's efficacy and safety in treating most allergic disorders. However, given its high cost, omalizumab is generally reserved for more severe cases of asthma and for asthma that responds poorly to conventional treatments.

Immunoglobulin E: role in asthma and allergic disease: lessons from the clinic

The role of immunoglobulin E (IgE) in allergic asthmatic disease is well established. Allergen-specific IgE binds to its cognate receptors, thus triggering a series of cellular events. These events include presentation of antigen by dendritic cells and the degranulation of mast cells and basophils to release numerous factors that play an integral part in potentiating the disease symptoms. Studies in the mouse indicate that a reduction in IgE levels could lead to significant attenuation of the allergic inflammatory response associated with diseases such as asthma, making IgE a target for the development of new therapeutic agents. Omalizumab (Xolair), a recombinant humanised monoclonal anti-IgE antibody that blocks the interaction of IgE with its receptors, is the first anti-IgE agent to undergo clinical development. Several clinical studies have been performed in adults and children with moderate-to-severe allergic asthma to evaluate the efficacy and safety of this agent, but which have also enabled an insight into the role of IgE in human disease. IgE plays a significant role in a number of allergic conditions including allergic rhinitis and allergies to various substances. Recent data suggests that local IgE production may occur in mucosal tissues and that locally significant concentrations of IgE, not reflected by serum IgE concentrations, indicate that it may play a role in non-atopic as well as atopic disease.

Pharmacologic and anti-IgE treatment of allergic rhinitis ARIA update (in collaboration with GA2LEN)

The pharmacologic treatment of allergic rhinitis proposed by ARIA is an evidence-based and step-wise approach based on the classification of the symptoms. The ARIA workshop, held in December 1999, published a report in 2001 and new information has subsequently been published. The initial ARIA document lacked some important information on several issues. This document updates the ARIA sections on the pharmacologic and anti-IgE treatments of allergic rhinitis. Literature published between January 2000 and December 2004 has been included. Only a few studies assessing nasal and non-nasal symptoms are presented as these will be discussed in a separate document.

Management of asthma with anti-immunoglobulin E: a review of clinical trials of omalizumab

Immunoglobulin E (IgE) is a key mediator of the inflammatory reactions that are central to the pathogenesis of allergic diseases such as asthma and rhinitis. The recognition of the importance of IgE in allergic disease led to the development of omalizumab, a humanized monoclonal anti-IgE antibody that binds free circulating IgE and prevents the interaction between IgE and high-affinity (FcepsilonRI) and low-affinity (FcepsilonRII) IgE receptors on inflammatory cells. By removing free IgE, omalizumab also markedly downregulates the expression of high-affinity receptors on basophils, mast cells and dendritic cells. Several studies have shown that omalizumab effectively reduces the risk of exacerbations and hospitalization and improves symptom control, lung function and quality of life in patients with severe persistent allergic asthma. Importantly, omalizumab has been shown to be effective in patients with poorly controlled severe persistent allergic asthma, a group of patients with few effective additional treatment options. In addition, omalizumab has been shown to provide effective relief from the symptoms of allergic rhinitis (including patients with concomitant asthma). Patients with uncontrolled severe persistent allergic asthma are a challenging and difficult-to-treat population for whom omalizumab might represent an important new treatment option. In addition, omalizumab may provide a means to address comorbid allergic disease in patients with asthma. Further investigation is also warranted to explore potential applications of omalizumab in occupational asthma.

Omalizumab : other indications and unanswered questions

Omalizumab, a recombinant humanized monoclonal antibody against immunoglobulin (Ig)E, represents a unique therapeutic approach for the treatment of allergic diseases. This agent acts as a neutralizing antibody by binding IgE at the same site as the high-affinity receptor. Subsequently, IgE is prevented from sensitizing cells bearing high-affinity receptors. Inhibition of the biological effects of IgE targets an early phase of the allergic cascade before the generation of allergic symptoms. Currently, omalizumab has been approved for the treatment of persistent allergic asthma in patients who are poorly controlled with inhaled corticosteroids. However, other allergic disorders may be amenable to treatment with omalizumab because of its ability to inhibit effector functions of IgE. Studies of omalizumab in the treatment of allergic rhinitis comprise the greater part of the literature pertaining to the use of this agent for clinical indications other than asthma. This article summarizes clinical trials of omalizumab in allergic rhinitis and examines the evidence regarding the effects of omalizumab on the pathophysiological mechanisms underlying allergic rhinitis. Additionally, we consider the role of this novel therapeutic agent in combination with specific allergen immunotherapy and discuss other potential indications for omalizumab in IgE-mediated disorders, including food allergy, latex allergy, atopic dermatitis, and chronic urticaria.