Targeting IgE in asthma

Magnesium isoglycyrrhizinate alleviate airway inflammatory responses in ovalbumin-induced mouse model of allergic asthma

OBJECTIVE

Asthma is a common chronic airway inflammatory disease, lacking effective therapeutic approaches. Magnesium isoglycyrrhizinate (MgIG) is an anti-inflammatory drug for treating chronic inflammation. However, it is still ambiguous whether MgIG can function in allergy induced asthma. In this study, we investigated the anti-inflammation effect of MgIG in mice with allergy induced asthma and explored the underlying mechanisms.

METHODS

Mouse asthma model was established with ovalbumin (OVA) sensitization and challenge. Subsequently, mice sensitized with OVA were randomly assigned into fourgroups: asthma model group (MDL), dexamethasone group (DXM), MgIG group (MgIG), and normal mice were used as normal control (CON). The mice in MgIG, MDL were given 0.2 mg/ml MgIG solution by atomization inhalation for 30 min before 1% (w/v) OVA challenge. At the completion of model establishment and drug treatment, cells in bronchoalveolar lavage fluid were classified, inflammatory factors in serum were determined, histopathological analysis was performed by H&E staining, and expression of MUC5AC, NLRP3, and cleaved caspase-1 in the lung tissue was also determined by immunohistochemistry and western blotting, respectively.

KEY FINDINGS

In comparison to MDL group, MgIG treatment could significantly inhibit the recruitment of white blood cells, neutrophils, and eosinophils in BALF, reduced the production of IL-6, TNF-α, and IgE in serum, and reduced mucus secretion and the infiltration of inflammatory cells. Also, an increase of NLRP3 and Caspase-1 protein levels were suppressed by MgIG treatment.

CONCLUSION

Our study findings support that nebulizer inhalation of MgIG as an effective therapy in treating the allergy induced asthma.

The Protective Effects of Maresin 1 in the OVA-Induced Asthma Mouse Model

Asthma is a chronic inflammatory disease that cannot be cured. Maresin 1 (MaR1) is a specific lipid synthesized by macrophages that exhibits powerful anti-inflammatory effects in various inflammatory diseases. The goal of this study was to evaluate the effect of MaR1 on allergic asthma using an ovalbumin- (OVA-) induced asthma model. Thirty BALB/c mice were randomly allocated to control, OVA, and MaR1 + OVA groups. Mice were sacrificed 24 hours after the end of the last challenge, and serum, bronchoalveolar lavage fluid (BALF), and lung tissue were collected for further analysis. Western blotting was used to measure the protein level of IκBα, the activation of the NF-κB signaling pathway, and the expression of NF-κB downstream inflammatory cytokines. Quantitative real-time polymerase chain reactions (qRT-PCRs) were used to evaluate the expression levels of COX-2 and ICAM-1 in lung tissues. We found that high doses of MaR1 were most effective in preventing OVA-induced inflammatory cell infiltration and excessive mucus production in lung tissue, reducing the number of inflammatory cells in the BALF and inhibiting the expression of serum or BALF-associated inflammatory factors. Furthermore, high-dose MaR1 treatment markedly suppressed the activation of the NF-κB signaling pathway, the degradation of IκBα, and the expression of inflammatory genes downstream of NF-κB, such as COX-2 and ICAM-1, in the OVA-induced asthma mouse model. Our findings indicate that MaR1 may play a critical role in OVA-induced asthma and may be therapeutically useful for the management of asthma.

Non-Invasive Delivery of Nano-Emulsified Sesame Oil-Extract of Turmeric Attenuates Lung Inflammation

Turmeric, the golden Indian spice, and the edible oil of sesame seeds are the essential ingredients of Indian food created by ancestors and established the belief of the curative effect of food for many generations. Considering the anti-inflammatory effects of turmeric, we formulated a nano-emulsion of turmeric infused in edible sesame oil, with a globule size of 200–250 nm using high-energy microfluidization. The product with a zeta potential of −11.5 mV showed spherical globules when imaged for scanning and transmission electron microscopy. We explored the anti-inflammatory potential of this edible nano-emulsion in lung inflammation. The lungs are the internal organ most vulnerable to infection, injury, and rapid inflammation from the external environment because of their constant exposure to pollutants, pathogenic microorganisms, and viruses. We evaluated the nano-emulsion for efficacy in ovalbumin-induced lung injury in mice with an oral treatment for two weeks. The therapeutic effect of nano-emulsion of the sesame oil-extract of turmeric was evident from biochemical analysis of bronchoalveolar lavage fluid, lung histopathology, and flow cytometric analysis. The developed nano-emulsion significantly reduced the inflammation and damage to the alveolar network in ovalbumin-injured mice. Significant reduction in the levels of neutrophils and inflammatory cytokines like IL-4, IL-6, and IL-13 in bronchoalveolar lavage fluid was observed in the nano-emulsion-treated group. Leukotriene B4 and IgE were also significantly altered in the treated group, thus suggesting the suitability of the formulation for the treatment of allergy and other inflammatory conditions. The nano-emulsification process potentiated the immunoregulatory effect of turmeric, as observed from the elevated levels of the natural anti-inflammatory cytokine, IL-10. The dietary constituents-based nano-emulsion of spice turmeric helped in scavenging the free radicals in the injured lungs, thus modulating the inflammation pathway. This easily scalable formulation technology approach can therefore serve as a potential noninvasive and safe treatment modality for reducing lung inflammation in lung injury cases.

Effect of individual allergen sensitization on omalizumab treatment outcomes in patients with severe allergic asthma determined using data from the Czech Anti-IgE Registry

Background

Omalizumab is an efficient drug for patients with uncontrolled severe allergic asthma (SAA). However, little is known about the differences in omalizumab treatment outcomes among patients with different types of atopic sensitization. Here, we assessed the effect of sensitization to individual allergens or their combinations on the outcomes of anti-IgE therapy in patients with SAA.

Methods

We performed a post hoc analysis of data of subgroups of patients enrolled in the Czech Anti-IgE Registry (CAR). The patients were evaluated at baseline and 16 weeks and 12 months after omalizumab treatment initiation. We analyzed the dependence of primary treatment outcomes [global evaluation of treatment effectiveness (GETE) after 16 weeks of treatment, a reduction in severe exacerbation rate (ER), and an improvement in the asthma control test (ACT) result during 12 months of treatment] and secondary outcomes [a reduction in systemic corticosteroid (SCS) use, an improvement in lung functions, and a fraction of exhaled nitric oxide] of patients with SAA treated with omalizumab for 12 months on sensitization to different perennial aeroallergens. We assessed sensitization to house dust mites, molds, and pets at baseline using skin prick tests and/or specific IgE measurement (semiquantitative evaluation). We compared polysensitized patients (sensitized to all tested allergens) with monosensitized (single positivity) or partially polysensitized patients (combined positivity but not to all allergens).

Results

We enrolled 279 patients (58.3% women, mean age 52.9 years). Omalizumab treatment presented an 82.8% response rate (according to GETE). It significantly reduced severe asthma exacerbations and SCS use, and improved the ACT result in 161 responders. We identified a subgroup of responders with distinct sensitization patterns (polysensitization to all tested perennial allergens) with higher odds of being responders (OR = 2.217, p = 0.02) and lower tendency to improve ACT result (OR 0.398, p = 0.023) and reduce ER (OR 0.431, p = 0.034) than non-polysensitized patients.

Conclusions

The clinical benefit of sensitization for patients with SAA receiving omalizumab may be particularly dependent on sensitization pattern. Polysensitized patients showed a higher tendency to be responders (GETE), but a lower tendency to improve the ACT result and reduce ER than non-polysensitized patients.

[Severe asthma revisited by biologic therapies emergences]

Severe asthma defined as uncontrolled or refractory asthma despite adequate use of high dose of inhaled steroid and additional long acting bronchodilators is associated with a high risk of comorbidities, exacerbations and persistent asthma-related symptoms. It remains a significant health care problem and represents the majority of health costs due to asthma. A better understanding of the basic mechanisms of the disease has allowed identification of new phenotypes and endotypes and of some predictive biomarkers. In the meantime an increasing number of promising biologicals are commercialized or on development providing new hopes to achieve asthma control and decrease exacerbation rate without the use of systemic corticosteroid. The increasing number of highly expensive available molecules poses physicians a new challenge: the identification of "the good treatment for the good patient". This article discuss the different biological available or in development in the field of severe asthma based on their mechanism of action and target. One of the aims is to help clarify the clinical decision-making process taking in account both the phenotype/endotype of the patient and the characteristics of these new drugs.

Bulleyaconitine A Effectively Relieves Allergic Lung Inflammation in a Murine Asthmatic Model

Background

Bulleyaconitine A (BLA) has been widely used as analgesic against chronic inflammatory pain in China. However, its potential therapeutic role in asthma remains unclear. The purpose of this study was to investigate the effect of BLA on airway inflammation in mice with allergic asthma.

Material/Methods

Specific-pathogen-free (SPF) female Balb/c mice were randomly divided into the following 6 groups: (1) Control group (NC), (2) Asthma group (AS), (3) BLA-L group, (4) BLA-M group, (5) BLA-H group, and (6) Dexamethasone group. An asthma mouse model was established by administration of ovalbumin (OVA) and mice were sacrificed within 24 h after the last challenge. Enzyme-linked immunosorbent assay (ELISA) method was used to determine the relative expression levels of IgE and IgG in mouse serum. In addition, bronchoalveolar lavage fluid (BALF) was collected and IL-4, TNF-α, and MCP-1 levels were determined by ELISA. Furthermore, eosinophils, lymphocytes, and macrophages in BALF were classified and analyzed, and inflammatory cell infiltration in the airways of mice was determined by hematoxylin-eosin (HE) staining. The expression of NF-κB1 and PKC-δ in mouse lung tissue was determined by Western blot analysis.

Results

The levels of serum IgE and IgG in BLA- or Dex- treated mice were significantly reduced compared to those in the asthma (AS) group (P<0.01), whereas the levels of cytokines IL-4, TNF-α, and MCP-1 were significantly decreased (P<0.01). HE-staining showed that BLA significantly reduced inflammatory cell infiltration and mucus secretion in lung tissue. Moreover, BLA inhibited the expression of NF-κB1 and PKC-δ via the NF-κB signaling pathway in the lung.

Conclusions

Our data show that BLA activates PKC-δ/NF-κB to reduce airway inflammation in allergic asthma mice.

Short- and long-term real-world effectiveness of omalizumab in severe allergic asthma: systematic review of 42 studies published 2008-2018

INTRODUCTION

Omalizumab is a recombinant monoclonal anti-IgE antibody approved in the US as add-on treatment in moderate-to-severe allergic asthma (in severe allergic asthma [SAA] in Europe). A 2016 review of 24 real-world effectiveness studies in SAA published between 2008-2015 concluded that omalizumab was associated with significant improvements in objective and subjective outcomes with benefits extending beyond 2 years. Several new real-world studies have been published since, bringing the total to 42 studies. Areas covered: This systematic review of 42 studies published since 2008 updates and extends the 2016 review on the real-word evidence on omalizumab in SAA. It offers greater granularity as to time windows within which outcomes are reported and includes studies extending well beyond 4 years post omalizumab initiation. Expert commentary: This review firmly establishes the short-term effectiveness of omalizumab in adolescent and adult patients with SAA at 1 year, and provides strong evidence of long-term effectiveness up to 4 years and emergent evidence of effectiveness beyond 4 years. In the aggregate, these 42 studies underscore the long-term effectiveness of omalizumab in terms of: reducing exacerbations and symptoms, achieving asthma control, improving lung function, enhancing quality of life, decreasing emergency department visits and hospitalizations, and promoting concomitant medication-sparing.

Small, Prospective, Observational, Pilot Study in Patients with Severe Asthma after Discontinuation of Omalizumab Treatment

PURPOSE

Omalizumab has demonstrated clinical efficacy in severe allergic asthma by reducing exacerbation rates and increasing quality of life. However, data concerning its sustained effect after treatment discontinuation are still needed.

METHODS

This analysis was an observational pilot study (simple within-subjects design) of 12 patients experiencing severe asthma, treated with omalizumab, for 1 year after treatment discontinuation. We prospectively analyzed clinical measurements (pulmonary functions, inhaled corticosteroid [ICS] doses, Asthma Control Test [ACT] scores, skin prick test [SPT] positivity, fraction of exhaled nitric oxide, and exacerbation rates) and laboratory test results (eosinophils and total immunoglobulin E levels) at the time of discontinuation and 6 and 12 months thereafter. Baseline data (before the treatment period; range, 11-61 months) were collected retrospectively. The treatment effect until discontinuation was calculated. To determine its persistence, repeated measures were compared with baseline levels and analyzed by using a general linear model for repeated measures or the Friedman ANOVA, and χ² tests in case of normality assumption violation or frequencies. Post hoc analysis was applied by using a simple or repeated contrasts analysis or Wilcoxon signed rank test with Bonferroni correction.

FINDINGS

We proved a significant reduction in ICS doses and SPT reactivity and an increase in ACT score during the retrospective treatment phase. Moreover, persistence of these statistically significant effects was recorded 6 months after treatment discontinuation. ACT score and ICS doses (but not SPT reactivity) remained improved for 12 months after discontinuation of omalizumab treatment.

IMPLICATIONS

Omalizumab treatment exhibited sustained treatment benefit after its discontinuation for patients experiencing severe allergic asthma.

Protostemonine attenuates alternatively activated macrophage and DRA-induced asthmatic inflammation

Asthma is one of the most common pulmonary diseases that threatens human life because of lack of effective medicines. Protostemonine (PSN), an active alkaloid extracted from the roots of Stemona sesslifolia, has anti-inflammatory effects on acute lung injury and acute liver failure. However, it has not been defined whether PSN alleviates asthmatic inflammation. Here, we reported that PSN inhibits pulmonary eosinophil infiltration, goblet cell hyperplasia, mucus secretion, IgE and Th2 cytokine (IL-4, IL-5, IL-13 and IL-33) production by using DRA (dust mites, ragweed and aspergillus)-induced murine asthma model. Moreover, PSN also attenuated the expression of Arginase-1 (Arg-1), Ym-1 and Fizz-1, markers of AAM (alternatively activated macrophage) polarization, in lung tissues. In addition, PSN attenuated IL-4-induced expression of Arg-1, Ym-1 and Fizz-1 in bone marrow derived macrophages (BMDMs). Treatment with PSN decreased IL-4-induced STAT6 phosphorylation, KLF4 and IRF4 expression in BMDMs. Collectively, our results indicated that PSN ameliorates AAM polarization and asthmatic inflammation and might be a potential agent for treating asthma.

Therapeutic antibodies: A new era in the treatment of respiratory diseases?

Respiratory diseases affect millions of people worldwide, and account for significant levels of disability and mortality. The treatment of lung cancer and asthma with therapeutic antibodies (Abs) is a breakthrough that opens up new paradigms for the management of respiratory diseases. Antibodies are becoming increasingly important in respiratory medicine; dozens of Abs have received marketing approval, and many more are currently in clinical development. Most of these Abs target asthma, lung cancer and respiratory infections, while very few target chronic obstructive pulmonary disease - one of the most common non-communicable causes of death - and idiopathic pulmonary fibrosis. Here, we review Abs approved for or in clinical development for the treatment of respiratory diseases. We notably highlight their molecular mechanisms, strengths, and likely future trends.

Precision medicine in asthma: the role of bronchial thermoplasty

PURPOSE OF REVIEW

The inflammatory makeup of severe asthma is heterogeneous. Identification of the predominant cellular endotype via biomarkers can aid in the selection of more advanced therapies. This review is clinically focused on how to use these biomarkers to help select between biologic agents and/or bronchial thermoplasty.

RECENT FINDINGS

Several Th2 biomarkers exist for the detection of eosinophilic disease; however, the best biomarker for clinical practice is debatable depending upon local resources. Currently, there are three federal drug agency-approved biologic agents (omalizumab, mepolizumab and reslizumab) to treat severe asthma with frequent exacerbations despite standard medical therapy. Several others are either in clinical trials or in the development phase for the treatment of eosinophilic asthma. To date, agents targeting neutrophilic inflammation have been largely unsuccessful. Bronchial thermoplasty has emerged as an option for the treatment of severe asthma.

SUMMARY

The appropriate selection of patients through the use of eosinophilic biomarkers has led to significant reductions in exacerbations with the use of mAb therapy. Bronchial thermoplasty has also shown reductions in asthma exacerbations and improved quality of life; however, it is unclear which patients may respond best to this intervention.

Novel targets of omalizumab in asthma

PURPOSE OF REVIEW

Omalizumab is a recombinant humanized anti-IgE monoclonal antibody approved in the US for moderate to severe persistent allergic asthma (severe persistent asthma in the European Union), uncontrolled despite treatment with inhaled corticosteroids and long-acting beta2 agonists. It reduces asthma exacerbations, symptoms, oral corticosteroid doses, and improves quality of life.

RECENT FINDINGS

Omalizumab may have an antiviral effect when used as a preventive therapy for fall exacerbations in children and teenagers. Two proof-of-concept studies have evaluated omalizumab in nonatopic asthma and showed that it is safe and possibly efficacious in some patients. Omalizumab has been successfully studied as add-on to specific immunotherapy in moderate allergic asthma. Its safety in pregnancy has been assessed in the EXPECT registry. Case series also report positive effects in cases of allergic bronchopulmonary aspergillosis, and in nasal disorders frequently associated with asthma. Last, omalizumab may have corticosteroid-sparing effect in a subset of patients with eosinophilic granulomatosis with polyangiitis (formerly Churg-Strauss syndrome).

SUMMARY

Recent studies argue in favor of positive effects of omalizumab beyond its current indications in asthma. Well-designed studies are needed in order to demonstrate the safety and efficacy of omalizumab in these possible novel indications.

Biologic therapy in the management of asthma

PURPOSE OF REVIEW

Current asthma management relies on inhaled corticosteroids, but some asthma is not well controlled with inhaled steroids alone or in combination with long-acting bronchodilators or leukotriene pathway inhibitors. The field of biologic therapy has grown dramatically in the past two decades, with current availability of three molecules, with two distinct and highly selective approaches to interfering with the allergic and eosinophilic airway inflammation common to most asthma. This review summarizes current and future options for incorporating biologic therapy into the overall management of asthma.

RECENT FINDINGS

Two new biologic agents have been recently introduced in the United States market, supported by well controlled, randomized clinical trials. These trials have provided insight into the types of patients who are most likely to benefit from these novel agents.

SUMMARY

In asthma patients with frequent exacerbations, the addition of a biologic agent targeting the interleukin-5 pathway, or immunoglobulin E, can significantly reduce exacerbations and improve asthma control. The clinical predictors of utility of specific agents overlap with one another, highlighting the importance of clinical judgment in the overall management of this complex disorder.

Appropriate selection for omalizumab treatment in patients with severe asthma?

Background: Omalizumab improves asthma control in patients with uncontrolled severe allergic asthma; however, appropriate patient selection is crucial. Information in this field is sparse.

Objective: We aimed to estimate whether potential omalizumab candidates were appropriately selected according to guidelines, and the clinical effect of omalizumab treatment over time.

Design: We performed a retrospective observational study on adult patients with asthma treated with omalizumab during 2006–2015 at the Department of Respiratory Medicine at Odense University Hospital (OUH), Denmark. Data were obtained from the Electronic Patient Journal of OUH and Odense Pharmaco-Epidemiological Database. Guideline criteria for omalizumab treatment were used to evaluate the appropriateness of omalizumab candidate selection, and the Asthma Control Test (ACT) to assess the clinical effects of omalizumab at weeks 16 and 52 from treatment initiation.

Results: During the observation period, 24 patients received omalizumab, but only 10 patients (42%) fulfilled criteria recommended by international guidelines. The main reasons for not fulfilling the criteria were inadequately reduced lung function, insufficient number of exacerbations, and asthma standard therapy below Global Initiative for Asthma (GINA) step 4–5. Seventeen and 11 patients completed treatment at weeks 16 and 52, with a statistically significant increase in ACT score of 5.1 points [95% confidence interval (CI) 3.1–7.2, p = 0.0001] and 7.7 points (95% CI 4.3–11.1, p = 0.0005), respectively.

Conclusion: Only 42% of the omalizumab-treated patients were appropriately selected according to current guidelines. Still, as omalizumab showed significant improvement in asthma control over time, it is important to keep this drug in mind as an add-on to asthma therapy in well-selected patients.

"Real-life" Effectiveness Studies of Omalizumab in Adult Patients with Severe Allergic Asthma: Meta-analysis

BACKGROUND

After the approval of omalizumab for severe allergic asthma, a total of 25 studies have evaluated the effectiveness of omalizumab under "real-life" conditions of heterogeneity in patients, clinicians, sites, and treatment patterns.

OBJECTIVE

We conducted a meta-analysis to evaluate the effectiveness of omalizumab focusing on treatment response, lung function, quality of life, symptom control, corticosteroid use, and exacerbations and hospitalizations at 4-6, 12, and 24 months.

METHODS

We searched PubMed and Embase for real-life studies on omalizumab in severe asthma published up to 2015. Three effect size types were extracted: single-point proportions; mean ± SD of change relative to baseline as raw numbers and standardized as Cohen's d; and changes in proportions of patients as relative risk. Random-effects meta-analyses were performed to account for within- and between-study heterogeneity. Studies were weighted by the DerSimonian and Laird method.

RESULTS

Per data available at the 3 time points, omalizumab therapy was consistently associated with large proportions of patients classified as "good" to "excellent" treatment responders (Global Evaluation of Treatment Effectiveness scale); improvements in forced expiratory volume in 1 second, quality of life (Asthma-related Quality-of-Life Questionnaire scale), and asthma symptom control (Asthma Control Test scale); reductions in oral and inhaled corticosteroid (ICS) use; and reductions in exacerbations and hospitalizations.

CONCLUSIONS

This meta-analysis of noncontrolled studies documents the real-life pharmacotherapeutic effectiveness of omalizumab, as add-on treatment to ICS ± long-acting β₂-agonists agents, in improving outcomes in patients with severe allergic asthma under conditions of heterogeneity in patients, clinicians, sites, and treatment patterns. The results mirror, complement, and extend the efficacy data from randomized controlled trials.

'Real-life' effectiveness studies of omalizumab in adult patients with severe allergic asthma: systematic review

We reviewed 24 'real-life' effectiveness studies of omalizumab in the treatment of severe allergic asthma that included 4117 unique patients from 32 countries with significant heterogeneity in patients, clinicians and settings. The evidence underscores the short- and long-term benefit of anti-IgE therapy in terms of the following: improving lung function; achieving asthma control and reducing symptomatology, severe exacerbations and associated work/school days lost; reducing healthcare resource utilizations, in particular hospitalizations, hospital lengths of stay and accident specialist or emergency department visits; reducing or discontinuing other asthma medications; and improving quality of life - thus confirming, complementing and extending evidence from randomized trials. Thus, omalizumab therapy is associated with signal improvements across the full objective and subjective burden of illness chain of severe allergic asthma. Benefits of omalizumab may extend up to 2-4 years, and the majority of omalizumab-treated patients may benefit for many years. Omalizumab has positive short- and long-term safety profiles similar to what is known from randomized clinical trials. Initiated patients should be monitored for treatment response at 16 weeks. Those showing positive response at that time are highly likely to show sustained treatment response and benefit in terms of clinical, quality of life and health resource utilization outcomes.

New and future strategies to improve asthma control in children

Symptomatic asthma in childhood has lifelong effects on lung function and disease severity, emphasizing the need for improved pediatric asthma control. Control of pediatric risk and impairment domains can be achieved through increased medication adherence or new therapeutic strategies. Developing electronic monitoring device technology with reminders might be a key noninvasive resource to address poor adherence in children and adolescents in a clinical setting. In patients who have persistently poor control despite optimal medication compliance, newly emerging pharmaceuticals, including inhaled therapies and biologics, might be key to their treatment. However, barriers exist to their development in the pediatric population, and insights must be drawn from adult studies, which has its own unique limitations. Biomarkers to direct the use of such potentially expensive therapies to those patients most likely to benefit are imperative. In this review the current literature regarding strategies to improve pediatric asthma control is addressed with the goal of exploring the potential and pitfalls of strategies that might be available in the near future.

Profile of omalizumab in the treatment of chronic spontaneous urticaria

Chronic spontaneous urticaria (CSU) is a disease with significant morbidity and relative prevalence that has important effects on the quality of life (QoL) of those who suffer from it. Omalizumab is a recombinant humanized anti-immunoglobulin E (IgE) antibody that binds to the Cε3 domain of the IgE heavy chain and prevents it from binding to its high-affinity receptor FcεRI. It has been largely studied in the field of asthma and is currently approved for the treatment of both adult and pediatric (children; >6-year-old) patients. In addition, in recent, well-controlled clinical trials in patients with CSU resistant to antihistamines, add-on therapy with subcutaneous omalizumab significantly reduced the severity of itching, and the number and size of hives, and increased patients' health-related QoL and the proportion of days free from angioedema compared with placebo, with an excellent tolerance. Thus, omalizumab is an effective and well-tolerated add-on therapy for patients with CSU who are symptomatic despite background therapy with H1 antihistamines. In this review, we cover the following points: epidemiology, pathogenesis, assessment of activity, impact on QoL, and treatment of CSU, and finally, we focus on omalizumab in the treatment of CSU including the pharmacokinetic properties and mechanism of action, and use in pregnant women, nursing infants, and children.

Interferon at the crossroads of allergy and viral infections

IFN-α/β was first described as a potent inhibitor of viral replication, but it is now appreciated that IFN signaling plays a pleiotropic role in regulating peripheral T cell functions. Recently, IFN-α/β was shown to block human Th2 development by suppressing the transcription factor GATA3. This effect is consistent with the role for IFN-α/β in suppressing allergic inflammatory processes by blocking granulocyte activation and IL-4-mediated B cell isotype switching to IgE. With the consideration of recent studies demonstrating a defect in IFN-α/β secretion in DCs and epithelial cells from individuals with severe atopic diseases, there is an apparent reciprocal negative regulatory loop in atopic individuals, whereby the lack of IFN-α/β secretion by innate cells contributes to the development of allergic Th2 cells. Is it possible to overcome these events by treating with IFN-α/β or by inducing its secretion in vivo? In support of this approach, case studies have documented the therapeutic potential of IFN-α/β in treating steroid-resistant allergic asthma and other atopic diseases. Additionally, individuals with asthma who are infected with HCV and respond to IFN therapy showed a reduction in symptoms and severity of asthma attacks. These findings support a model, whereby allergic and antiviral responses are able to cross-regulate each other, as IgER cross-linking of pDCs prevents IFN-α/β production in response to viral infection. The clinical importance of upper-respiratory viruses in the context of allergic asthma supports the need to understand how these pathways intersect and to identify potential therapeutic targets.

Suppression of dust mite allergy by mucosal delivery of a hypoallergenic derivative in a mouse model

Allergic asthma caused by house dust mite (HDM) is becoming a public health problem. Specific immunotherapy is considered to be the only curative treatment, but it is always associated with IgE-mediated side effects in the therapy process. A few studies showed that the disruption of allergen IgE epitopes could reduce IgE reactivity and thus reduce allergenic activity. In this study, a hypoallergenic derivative of the major HDM allergen Der p2 was constructed by genetic engineering. This derivative was confirmed to have a considerably reduced IgE reactivity compared with Der p2. For its application in vivo, recombinant Lactococcus lactis (LL-DM) was engineered to deliver the Der p2 derivative to the intestinal mucosal surface. Oral administration of LL-DM significantly alleviated Der p2-induced airway inflammation, as shown by reduced inflammatory infiltration and a reduction in Th2 cytokines in bronchoalveolar lavage. This protective effect was associated with an up-regulation of specific IgG2a and a decrease in IL-4 level in the spleen which may affect specific IgE response. Moreover, the levels of regulatory T cells in the mesenteric lymph nodes and spleen were markedly increased in mice fed with LL-DM, suggesting that LL-DM can inhibit allergic responses via the induction of regulatory T cell. Our results indicate that the Der p2 derivative is a promising therapeutic molecule for specific immunotherapy and recombinant lactic acid bacteria could be developed as a promising treatment or prevention strategy for allergic diseases.

TRIF Deficiency does not Affect Severity of Ovalbumin-induced Airway Inflammation in Mice

Allergic asthma is a chronic pulmonary inflammatory disease characterized by reversible airway obstruction, hyperresponsiveness and eosinophils infiltration. Toll-like receptors (TLRs) signaling are closely associated with asthma and have emerged as a novel therapeutic target in allergic disease. The functions of TLR3 and TLR4 in allergic airway inflammation have been studied; however, the precise role of TIR-domain-containing adapter-inducing interferon-β (TRIF), the adaptor molecule for both TLR3 and TLR4, is not yet fully understood. To investigate this, we developed a mouse model of OVA-induced allergic airway inflammation and compared the severity of allergic airway inflammation in WT and TRIF^-/- mice. Histopathological assessment revealed that the severity of inflammation in airway inflammation in TRIF-deficient mice was comparable to that in WT mice. The total number of cells recovered from bronchoalveolar lavage fluid did not differ between WT and TRIF-deficient mice. Moreover, TRIF deficiency did not affect Th1 and Th2 cytokine production in lung tissue nor the level of serum OVA-specific IgE, IgG₁ and IgG_2c. These findings suggest that TRIF-mediated signaling may not be critical for the development of allergic airway inflammation.

Targeting IgE production in mice and humans

Immunoglobulin E (IgE) is pathogenic in allergic diseases such as asthma, allergic rhinitis, atopic dermatitis, and food allergy. Recent studies using genetically modified IgE reporter mice indicate that the majority of serum IgE in mice is produced by short-lived IgE plasma cells, with minor contributions from long-lived IgE plasma cells, and implicate IgG1 and IgE memory B cells as potential sources of IgE memory. Clinical studies using antibodies against IL-13 or the IL-4 and IL-13 receptor subunit IL-4Rα, as well as an antibody against the M1 prime domain of human membrane IgE, indicate that, similar to mice, a proportion of IgE in humans is derived from ongoing IgE immune responses and short-lived plasma cells. Targeting IgE production may lead to new therapies for the treatment of allergic diseases.

Upregulated interleukin-21 receptor on B cells associated with the downregulation of IgE in patients with allergic rhinitis

Allergic diseases, such as allergic rhinitis, caused by an immunoglobulin E (IgE)-mediated reaction to specific allergens are a common chronic condition worldwide. Interleukin-21 (IL-21), a type I cytokine that is produced by T cells, exerts regulatory effects on a variety of immune cells. In our previous study, we found that serum levels of IL-21 were significantly decreased in patients with severe atopic dermatitis, suggesting that IL-21 might play a role in allergic reactions. In this study, we investigated the role of IL-21/IL-21 receptor (IL-21R) in patients with allergic rhinitis. Our results demonstrated that there was no difference in IL-21 serum levels between allergic rhinitis patients and controls. However, allergic patients had significantly increased expression of IL-21R on naive and memory B cells. IL-21R was upregulated through stimulation by the combination of CD40 ligand (CD40L) and IL-4. IL-21 alone neither induced nor inhibited IgE secretion from CD40L-stimulated B cells. However, IL-21 inhibited IgE secretion of B cells that were induced by the combination of CD40L and IL-4 in allergic patients. Moreover, a negative correlation between the expression of IL-21R and serum levels of IgE was found in patients with allergy. These results suggest that the role of IL-21 in an ongoing allergic reaction is to downregulate the IgE level by binding to IL-21R on B cells, which increases the expression in allergic patients.

Omalizumab in asthma: an update on recent developments

IgE is central to the pathophysiology of allergic asthma. Omalizumab, a humanized anti-IgE mAb, specifically binds free IgE and interrupts the allergic cascade by preventing binding of IgE with its high-affinity FcεRI receptors on mast cells, antigen-presenting cells, and other inflammatory cells. The clinical efficacy of omalizumab has been well documented in a number of clinical trials that involve adults, adolescents, and children with moderate-to-severe and severe allergic asthma. In these studies, omalizumab reduced exacerbations, asthma symptoms, inhaled corticosteroid and rescue medication use, and improved quality of life relative to placebo or best standard of care. Similar benefits have been reported in observational studies in "real-world" populations of patients. Results from recent pooled data from randomized clinical trials and from a large prospective cohort study provide reassurance about the long-term safety of omalizumab. Omalizumab dosing is individualized according to body weight and serum-IgE level, and recent adjustments to the dosing algorithm in Europe have enabled more patients to be eligible for treatment. Ongoing and future research is investigating the optimal duration of therapy, accurate predictors of response to treatment, and efficacy in nonatopic asthma as well as other IgE-mediated conditions.

Omalizumab in patients with allergic (IgE-mediated) asthma and IgE/bodyweight combinations above those in the initially approved dosing table

BACKGROUND

When first approved in the European Union (EU), the omalizumab dosing table had upper bodyweight and IgE limits of 150 kg and 700 IU/mL, respectively. In this study, we assessed the safety, pharmacokinetics (PK) and pharmacodynamics (PD) of omalizumab in patients with IgE/bodyweight combinations above those in the original dosing table.

METHODS

A multicentre, open-label, parallel-group study assessed the safety, PK and PD of omalizumab in 32 patients with mild-to-moderate allergic (IgE-mediated) asthma. Patients received two subcutaneous injections of omalizumab at one of three dosage levels (450, 525, or 600 mg), chosen according to baseline IgE (300-2000 IU/mL) and bodyweight (40-150 kg), with a 14-day interval between injections.

RESULTS

Overall, 69 adverse events (AEs), none of them serious, were reported by 26 (81.3%) patients. Analysis of laboratory measurements, vital signs and ECG data revealed no adverse findings of clinical relevance. The PK profile was consistent with previous data for lower doses. Mean maximum decrease of free IgE from screening was ≥99% for all three doses, and mean free IgE concentrations remained <25 ng/mL for at least 2 weeks after the second dose. The reductions in free IgE were consistent with levels previously associated with clinical improvements.

CONCLUSIONS

The safety and PK/PD findings from this study are consistent with previous data, and supported the extension of the omalizumab dosing table to include those patients with higher IgE/bodyweight combinations. Clinical trial registry and registration number: clinicaltrials.gov (NCT00546143).

Heterologous microarray analysis of transcriptome alterations in Mus spretus mice living in an industrial settlement

This work demonstrates the successful application of a commercial oligonucleotide microarray containing Mus musculus whole-genome probes to assess the biological effects of an industrial settlement on inhabitant Mus spretus mice. The transcriptomes of animals in the industrial settlement contrasted with those of specimens collected from a nearby protected ecosystem. Proteins encoded by the differentially expressed genes were broadly categorized into six main functional classes. Immune-associated genes were mostly induced and related to innate and acquired immunity and inflammation. Genes sorted into the stress-response category were mainly related to oxidative-stress tolerance and biotransformation. Metabolism-associated genes were mostly repressed and related to lipid metabolic pathways; these included genes that encoded 11 of the 20 cholesterol biosynthetic pathway enzymes. Crosstalk between members of different functional categories was also revealed, including the repression of serine-protease genes and the induction of protease-inhibitor genes to control the inflammatory response. Absolute quantification of selected transcripts was performed via RT-PCR to verify the microarray results and assess interindividual variability. Microarray data were further validated by immunoblotting and by cholesterol and protein-thiol oxidation level determinations. Reported data provide a broad impression of the biological consequences of residing in an industrial area.

Receptor Interacting Protein 2 (RIP2) Is Dispensable for OVA-Induced Airway Inflammation in Mice

Purpose

Asthma is a pulmonary chronic inflammatory disease characterized by airway obstruction and hyperresponsiveness. Pattern recognition receptors are known to play a key role in the development of allergic diseases as well as host defenses against microbial infection. Receptor interacting protein 2 (RIP2), a serine/threonine kinase, is an adaptor molecule of NOD1 and NOD2, and genetic variation in this receptor is known to be associated with the severity of allergic asthma in children. In this study, we examined the role of RIP2 in the development of allergic airway inflammation in a mouse model.

Methods

Airway inflammation was induced in mice through intranasal administration of ovalbumin (OVA) after 2 intraperitoneal immunizations with OVA. Lung inflammation and mucus hypersecretion were examined histologically and total cell infiltration in bronchoalveolar (BAL) fluids was determined. Levels of the Th2-related cytokines, IL-5 and IL-13, in lung extracts were measured by ELISA. Serum antigen-specific IgE and IgG1 levels were also assessed.

Results

OVA-induced lung inflammation and mucus hypersecretion were not different between WT and RIP2-deficient mice. The IL-5 and IL-13 levels in the bronchoalveolar (BAL) fluids were also not impaired in RIP2-deficient mice compared to WT mice. Moreover, RIP2 deficiency did not affect serum OVA-specific IgG1 and IgE levels.

Conclusions

Our results suggest that RIP2 is not associated with the development of allergic airway inflammation.

The therapeutic potential of Toll-like receptor 7 stimulation in asthma

Asthma is an inflammatory disorder of the airways frequently characterized by an excessive Th2 adaptive immune response. Activation of Toll-like receptor (TLR)-7, a single-stranded viral RNA receptor that is highly expressed in the airways, triggers a rapid innate immune response and favors a subsequent Th1 response. Because of this role in pulmonary immunoregulation, TLR7 has gained considerable interest as a therapeutic target in asthma. Synthetic TLR7 ligands, including the imidazoquinolines imiquimod (R837) and resiquimod (R848), and 8-hydroxyadenine derivatives have been developed for other clinical indications. TLR7 activation prevents ovalbumin-induced airway hyperreactivity, eosinophilic inflammation, goblet cell hyperplasia and airway remodeling in murine models of asthma. TLR7 activation also inhibits viral replication in the lung and prevents virus-induced airway hyperreactivity. Furthermore, it has recently been shown that stimulating TLR7 rapidly relaxes airway smooth muscle, dilating the airways. This bronchodilating effect, which occurs in seconds to minutes and depends on rapid production of nitric oxide, indicates that TLR7 can signal via previously unrecognized pathways. The effects of decreasing the allergic Th2 response, acting as an immediate bronchodilator, and promoting an antiviral immune environment, make TLR7 an attractive drug target. We examine the current understanding of TLR7 as a therapeutic target and its translation to asthma treatment in humans.

Biomarker surrogates do not accurately predict sputum eosinophil and neutrophil percentages in asthmatic subjects

BACKGROUND

Sputum eosinophil percentages are a strong predictor of airway inflammation and exacerbations and aid asthma management, whereas sputum neutrophil percentages indicate a different severe asthma phenotype that is potentially less responsive to TH2-targeted therapy. Variables, such as blood eosinophil counts, total IgE levels, fraction of exhaled nitric oxide (Feno) levels, or FEV1 percent predicted, might predict airway eosinophil percentages, whereas age, FEV1 percent predicted, or blood neutrophil counts might predict sputum neutrophil percentages. Availability and ease of measurement are useful characteristics, but accuracy in predicting airway eosinophil and neutrophil percentages either individually or combined is not established.

OBJECTIVES

We sought to determine whether blood eosinophil counts, Feno levels, and IgE levels accurately predict sputum eosinophil percentages and whether age, FEV1 percent predicted, and blood neutrophil counts accurately predict sputum neutrophil percentages.

METHODS

Subjects in the Wake Forest Severe Asthma Research Program (n = 328) were characterized by blood and sputum cell counts, health care use, lung function, Feno levels, and IgE levels. Multiple analytic techniques were used.

RESULTS

Despite significant association with sputum eosinophil percentages, blood eosinophil counts, Feno levels, and total IgE levels did not accurately predict sputum eosinophil percentages, and combinations of these variables did not improve prediction. Age, FEV1 percent predicted, and blood neutrophil counts were similarly unsatisfactory for the prediction of sputum neutrophil percentages. Factor analysis and stepwise selection found Feno levels, IgE levels, and FEV1 percent predicted, but not blood eosinophil counts, correctly predicted 69% of sputum eosinophil percentages of less than 2% or 2% and greater. Likewise, age, asthma duration, and blood neutrophil counts correctly predicted 64% of sputum neutrophil percentages of less than 40% or 40% and greater. A model to predict both sputum eosinophil and neutrophil percentages accurately assigned only 41% of samples.

CONCLUSION

Despite statistically significant associations, Feno levels, IgE levels, blood eosinophil and neutrophil counts, FEV1 percent predicted, and age are poor surrogates, both separately and combined, for accurately predicting sputum eosinophil and neutrophil percentages.

Sesame oil attenuates ovalbumin-induced pulmonary edema and bronchial neutrophilic inflammation in mice

Background. Allergic asthma is one of the most common chronic inflammatory diseases of airways. Severe asthma may lead to hospitalization and death. Sesame oil is a natural product with anti-inflammatory property. However, the effect of sesame oil on allergic asthma has never been studied. Objective. We investigate the effect of sesame oil on pulmonary inflammation in allergic asthma model. Methods. Allergic airway inflammation was induced by sensitizing with two doses of 10 mg ovalbumin (OVA) and then challenged with 1% OVA nebulizer exposure (1 h/day) for 3 days. Sesame oil (0.25, 0.5, or 1 mL/kg/day) was given orally 30 min before each challenge. Samples were collected 24 h after the last challenge. Results. Data showed that sesame oil inhibited pulmonary edema and decreased interleukin (IL)-1β and IL-6 levels in bronchoalveolar lavage fluid in OVA-treated mice. Sesame oil also decreased pulmonary nitrite level, inducible nitric oxide synthase expression, and neutrophil infiltration induced by OVA. Further, sesame oil decreased serum IgE level in OVA-treated mice. Conclusion. Sesame oil may attenuate pulmonary edema and bronchial neutrophilic inflammation by inhibiting systemic IgE level in allergic asthma.

A time-resolved fluorescence resonance energy transfer assay suitable for high-throughput screening for inhibitors of immunoglobulin E-receptor interactions

The interaction of immunoglobulin E (IgE) antibodies with the high-affinity receptor, FcεRI, plays a central role in initiating most allergic reactions. The IgE-receptor interaction has been targeted for treatment of allergic diseases, and many high-affinity macromolecular inhibitors have been identified. Small molecule inhibitors would offer significant advantages over current anti-IgE treatment, but no candidate compounds have been identified and fully validated. Here, we report the development of a time-resolved fluorescence resonance energy transfer (TR-FRET) assay for monitoring the IgE-receptor interaction. The TR-FRET assay measures an increase in fluorescence intensity as a donor lanthanide fluorophore is recruited into complexes of site-specific Alexa Fluor 488-labeled IgE-Fc and His-tagged FcεRIα proteins. The assay can readily monitor classic competitive inhibitors that bind either IgE-Fc or FcεRIα in equilibrium competition binding experiments. Furthermore, the TR-FRET assay can also be used to follow the kinetics of IgE-Fc-FcεRIα dissociation and identify inhibitory ligands that accelerate the dissociation of preformed complexes, as demonstrated for an engineered DARPin (designed ankyrin repeat protein) inhibitor. The TR-FRET assay is suitable for high-throughput screening (HTS), as shown by performing a pilot screen of the National Institutes of Health (NIH) Clinical Collection Library in a 384-well plate format.

IL-13 in asthma and allergic disease: asthma phenotypes and targeted therapies

Decades of research in animal models have provided abundant evidence to show that IL-13 is a key T(H)2 cytokine that directs many of the important features of airway inflammation and remodeling in patients with allergic asthma. Several promising focused therapies for asthma that target the IL-13/IL-4/signal transducer and activator of transcription 6 pathway are in development, including anti-IL-13 mAbs and IL-4 receptor antagonists. The efficacy of these new potential asthma therapies depends on the responsiveness of patients. However, an understanding of how IL-13-directed therapies might benefit asthmatic patients is confounded by the complex heterogeneity of the disease. Recent efforts to classify subphenotypes of asthma have focused on sputum cellular inflammation profiles, as well as cluster analyses of clinical variables and molecular and genetic signatures. Researchers and clinicians can now evaluate biomarkers of T(H)2-driven airway inflammation in asthmatic patients, such as serum IgE levels, sputum eosinophil counts, fraction of exhaled nitric oxide levels, and serum periostin levels, to aid decision making in clinical trials and drug development and to identify subsets of patients who might benefit from therapies. Although it is unlikely that these therapies will benefit all asthmatic patients with this heterogeneous disease, advances in understanding asthma subphenotypes in relation to clinical variables and T(H)2 cytokine responses offer the opportunity to improve the efficacy and safety of proposed therapies for asthma.

Emerging drugs for asthma

INTRODUCTION

Current drug treatments for asthma relieve bronchospasm and airway inflammation but do not offer a cure, and symptoms return when treatment is stopped. Asthma management guidelines emphasize the importance of effective asthma treatment to achieve and maintain asthma control. However, despite widely available and effective treatments, achieving asthma control is still an unmet need for many patients.

AREAS COVERED

Remarkable efforts have been made to identify the characteristic features of difficult-to-control (usually severe) asthma that are different from those described for mild-to-moderate asthma, setting the stage for the development of new and even individualized therapies. The most fascinating options of the new asthma treatments are biologic therapies, in particular monoclonal antibodies. In addition, some novel once-daily combinations of long-acting β(2)-agonist and inhaled corticosteroids are under development.

EXPERT OPINION

Asthma is a complex syndrome made up of a number of disease variants or asthma phenotypes, with different underlying pathophysiology. As different drugs target different pathways, it is necessary to determine the individual profile of pathophysiological abnormalities for each patient. Several cytokines have been implicated in the inflammatory cascades leading to the different asthma phenotypes, and the most relevant ones are discussed. The challenge in treating asthma resides precisely in its heterogeneity.