Does anti-IgE therapy help in asthma? Efficacy and controversies

The effect of COVID-19 on patients with chronic spontaneous urticaria treated with omalizumab and antihistamines: A cross-sectional, comparative study

Introduction

Chronic spontaneous urticaria (CSU) is defined as recurrent attacks of urticaria present for more than six weeks. The monoclonal anti‐immunoglobulin E antibody, omalizumab, was approved for the treatment of CSU in patients who remain refractory to H1‐antihistamines. Biologic agents are shown not to increase the risk of COVID‐19 infection in different studies.

Objective

In the present study, we aimed to determine the prevalance of COVID‐19 infection in relation to the age, gender, presence of other comorbidities, and treatment given for CSU.

Methods

We conducted a descriptive cross‐sectional study of 233 patients diagnosed with CSU in a tertiary referral hospital. Demographical data, treatment given for CSU, the presence of COVID‐19‐related symptoms, history of close contact to a person with COVID‐19 and COVID‐19 real‐time polymerase chain reaction (RT‐PCR) results were determined via a telephone survey and checked from medical data records.

Results

One hundred sixty patients were female; whereas 73 were male. The mean age was 44.76. Out of 233 patients with chronic urticaria, 125 had symptoms related to COVID‐19 infection. RT‐PCR testing for COVID‐19 was performed in 156 patients. Of 156 patients with COVID‐19 RT‐PCR test, RT‐PCR result was positive in 15 cases.

Conclusions

No statistically significant relationship was found between COVID‐19 RT‐PCR positivity and the type of treatment administered for chronic urticaria when the patients are divided into omalizumab ± oral antihistamines and only oral antihistamines treatment groups (p = 0.150). Omalizumab seems to be safe in the era of COVID‐19.

Anti-IgE Monoclonal Antibody in Allergic Bronchopulmonary Aspergillosis Not Responding to Systemic Steroids

Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity disorder caused by Aspergillus fumigatus commonly among patients of bronchial asthma. Early diagnosis is the key to successful management and preventing parenchymal destruction. Most of the patients respond well to systemic steroids. In patients not responding to standard treatment, the other treatment options include pulse steroids, antifungals, immunosuppressants, and omalizumab. But exact indication for each of these is not well established. Here we report a 41-year-old ABPA patient who was not responding to systemic steroids became totally asymptomatic with the administration of omalizumab.

CD4⁺ and CD8⁺ T cells play a central role in a HDM driven model of allergic asthma

Background

The incidence of asthma is increasing at an alarming rate and while the current available therapies are effective in the majority of patients they fail to adequately control symptoms at the more severe end of the disease spectrum. In the search to understand disease pathogenesis and find effective therapies animal models are often employed. As exposure to house dust mite (HDM) has a causative link, it is thought of as the allergen of choice for modelling asthma.

The objective was to develop a HDM driven model of asthmatic sensitisation and characterise the role of key allergic effector cells/mediators.

Methods

Mice were sensitised with low doses of HDM and then subsequently challenged. Cellular inflammation, IgE and airway responsiveness (AHR) was assessed in wild type mice or CD4⁺/CD8⁺ T cells, B cells or IgE knock out mice.

Results

Only those mice sensitised with HDM responded to subsequent low dose topical challenge. Similar to the classical ovalbumin model, there was no requirement for systemic alum sensitisation. Characterisation of the role of effector cells demonstrated that the allergic cellular inflammation and AHR was dependent on CD4⁺ and CD8⁺ T cells but not B cells or IgE. Finally, we show that this model, unlike the classic OVA model, appears to be resistant to developing tolerance.

Conclusions

This CD4⁺/CD8⁺ T cell dependent, HDM driven model of allergic asthma exhibits key features of asthma. Furthermore, we suggest that the ability to repeat challenge with HDM means this model is amenable to studies exploring the effect of therapeutic dosing in chronic, established disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0359-y) contains supplementary material, which is available to authorized users.

A genome-wide association study of total serum and mite-specific IgEs in asthma patients

Immunoglobulin E (IgE) is one of the central players in asthma and allergic diseases. Although the serum IgE level, a useful endophenotype, is generally increased in patients with asthma, genetic factors influencing IgE regulation in asthma are still not fully understood. To identify the genetic variations associated with total serum and mite-specific IgEs in asthmatics, a genome-wide association study (GWAS) of 657,366 single nucleotide polymorphisms (SNPs) was performed in 877 Korean asthmatics. This study found that several new genes might be associated with total IgE in asthmatics, such as CRIM1 (rs848512, P = 1.18×10⁻⁶; rs711254, P = 6.73×10⁻⁶), ZNF71 (rs10404342, P = 7.60×10⁻⁶), TLN1 (rs4879926, P = 7.74×10⁻⁶), and SYNPO2 (rs1472066, P = 8.36×10⁻⁶; rs1038770, P = 8.66×10⁻⁶). Regarding the association of specific IgE to house dust mites, it was observed that intergenic SNPs nearby to OPRK1 and LOC730217 might be associated with Dermatophagoides pteronyssinus (D.p.) and Dermatophagoides farinae (D.f.) in asthmatics, respectively. In further pathway analysis, the phosphatidylinositol signaling system and adherens junction pathways were estimated to play a role in the regulation of total IgE levels in asthma. Although functional evaluations and replications of these results in other populations are needed, this GWAS of serum IgE in asthmatics could facilitate improved understanding of the role of the newly identified genetic variants in asthma and its related phenotypes.

Minocycline blocks asthma-associated inflammation in part by interfering with the T cell receptor-nuclear factor κB-GATA-3-IL-4 axis without a prominent effect on poly(ADP-ribose) polymerase

Minocycline protects against asthma independently of its antibiotic function and was recently reported as a potent poly(ADP-ribose) polymerase (PARP) inhibitor. In an animal model of asthma, a single administration of minocycline conferred excellent protection against ovalbumin-induced airway eosinophilia, mucus hypersecretion, and Th2 cytokine production (IL-4/IL-5/IL-12(p70)/IL-13/GM-CSF) and a partial protection against airway hyperresponsiveness. These effects correlated with pronounced reduction in lung and sera allergen-specific IgE. A reduction in poly(ADP-ribose) immunoreactivity in the lungs of minocycline-treated/ovalbumin-challenged mice correlated with decreased oxidative DNA damage. The effect of minocycline on PARP may be indirect, as the drug failed to efficiently block direct PARP activation in lungs of N-methyl-N'-nitro-N-nitroso-guanidine-treated mice or H(2)O(2)-treated cells. Minocycline blocked allergen-specific IgE production in B cells potentially by modulating T cell receptor (TCR)-linked IL-4 production at the mRNA level but not through a modulation of the IL-4-JAK-STAT-6 axis, IL-2 production, or NFAT1 activation. Restoration of IL-4, ex vivo, rescued IgE production by minocycline-treated/ovalbumin-stimulated B cells. IL-4 blockade correlated with a preferential inhibition of the NF-κB activation arm of TCR but not GSK3, Src, p38 MAPK, or ERK1/2. Interestingly, the drug promoted a slightly higher Src and ERK1/2 phosphorylation. Inhibition of NF-κB was linked to a complete blockade of TCR-stimulated GATA-3 expression, a pivotal transcription factor for IL-4 expression. Minocycline also reduced TNF-α-mediated NF-κB activation and expression of dependent genes. These results show a potentially broad effect of minocycline but that it may block IgE production in part by modulating TCR function, particularly by inhibiting the signaling pathway, leading to NF-κB activation, GATA-3 expression, and subsequent IL-4 production.

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

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

A potential new target for asthma therapy: a disintegrin and metalloprotease 10 (ADAM10) involvement in murine experimental asthma

BACKGROUND

Elevated levels of CD23, a natural regulator of IgE production, have been shown to decrease the signs of lung inflammation in mice. The aim of this study was to study the involvement of ADAM10, the primary CD23 sheddase, in experimental asthma.

METHODS

ADAM10 was blocked either by using mice with a B-cell-specific deletion of the protease or pharmacologically by intranasal administration of selective ADAM10 inhibitors. Airway hypersensitivity (AHR) and bronchoaveolar lavage fluid (BALF) eosinophilia and select BALF cytokine/chemokine levels were then determined.

RESULTS

Using an IgE and mast cell-dependent mouse model, B-cell-specific ADAM10(-/-) mice (C57B/6 background) exhibited decreased eosinophilia and AHR when compared with littermate (LM) controls. Treatment of C57B/6 mice with selective inhibitors of ADAM10 resulted in an even further decrease in BALF eosinophilia, as compared with the ADAM10(-/-) animals. Even in the Th2 selective strain, Balb/c, BALF eosinophilia was reduced from 60% to 23% respectively. In contrast, when an IgE/mast cell-independent model of lung inflammation was used, the B-cell ADAM10(-/-) animals and ADAM10 inhibitor treated animals had lung inflammation levels that were similar to the controls.

CONCLUSIONS

These results thus show that ADAM10 is important in the progression of IgE-dependent lung inflammation. The use of the inhibitor further suggested that ADAM10 was important for maintaining Th2 levels in the lung. These results thus suggest that decreasing ADAM10 activity could be beneficial in controlling asthma and possibly other IgE-dependent diseases.

Antigen-Specific IgG ameliorates allergic airway inflammation via Fcγ receptor IIB on dendritic cells

Background

There have been few reports on the role of Fc receptors (FcRs) and immunoglobulin G (IgG) in asthma. The purpose of this study is to clarify the role of inhibitory FcRs and antigen presenting cells (APCs) in pathogenesis of asthma and to evaluate antigen-transporting and presenting capacity by APCs in the tracheobronchial mucosa.

Methods

In FcγRIIB deficient (KO) and C57BL/6 (WT) mice, the effects of intratracheal instillation of antigen-specific IgG were analysed using the model with sensitization and airborne challenge with ovalbumin (OVA). Thoracic lymph nodes instilled with fluorescein-conjugated OVA were analysed by fluorescence microscopy. Moreover, we analysed the CD11c⁺ MHC class II⁺ cells which intaken fluorescein-conjugated OVA in thoracic lymph nodes by flow cytometry. Also, lung-derived CD11c⁺ APCs were analysed by flow cytometry. Effects of anti-OVA IgG1 on bone marrow dendritic cells (BMDCs) in vitro were also analysed. Moreover, in FcγRIIB KO mice intravenously transplanted dendritic cells (DCs) differentiated from BMDCs of WT mice, the effects of intratracheal instillation of anti-OVA IgG were evaluated by bronchoalveolar lavage (BAL).

Results

In WT mice, total cells and eosinophils in BAL fluid reduced after instillation with anti-OVA IgG1. Anti-OVA IgG1 suppressed airway inflammation in hyperresponsiveness and histology. In addition, the number of the fluorescein-conjugated OVA in CD11c⁺ MHC class II⁺ cells of thoracic lymph nodes with anti-OVA IgG1 instillation decreased compared with PBS. Also, MHC class II expression on lung-derived CD11c⁺ APCs with anti-OVA IgG1 instillation reduced. Moreover, in vitro, we showed that BMDCs with anti-OVA IgG1 significantly decreased the T cell proliferation. Finally, we demonstrated that the lacking effects of anti-OVA IgG1 on airway inflammation on FcγRIIB KO mice were restored with WT-derived BMDCs transplanted intravenously.

Conclusion

Antigen-specific IgG ameliorates allergic airway inflammation via FcγRIIB on DCs.

Suppression of IgE B cells and IgE binding to Fc(epsilon)RI by gene therapy with single-chain anti-IgE

IgE plays a pivotal role in allergic reactions and asthma through its ability to bind to the mast cell FcR for IgE (FcepsilonRI). Current therapies to suppress such reactions include passive treatment with neutralizing Abs to IgE that block its binding to FcepsilonRI. In theory, induction of immune tolerance in the B lymphocytes that carry IgE Ag receptors and give rise to IgE-secreting cells should provide longer term efficacy. However, recent data have suggested that such memory cells may lack cell surface IgE. Using a gene therapy approach, we show that a recombinant single-chain neutralizing anti-IgE could not only neutralize circulating IgE, but also reduce IgE(+) B cell numbers and H chain transcripts. Therapeutic anti-IgE stimulated a calcium response in primary B cells or in a B cell line expressing membrane IgE and suppressed IgE secretion in vitro, suggesting that active signaling through membrane IgE likely promoted tolerance. Interestingly, upon subsequent challenge of anti-IgE-treated mice with an IgE cross-linking reagent capable of inducing activation of IgE-decorated mast cells, an anaphylaxis reaction was induced, apparently via a FcgammaRIII pathway involving recognition of anti-IgE Ab itself. These studies have important implications for the optimal design of safe and effective anti-IgE therapies and suggest that the IgE memory B cells may be targeted by such genetic Ab therapies.

Intrinsic asthma: not so different from allergic asthma but driven by superantigens?

The mechanisms of intrinsic or non-allergic asthma remain uncertain as allergens have no obvious role in driving the inflammatory process in the airways. However, IgE synthesis occurs in the airways, despite negative skin prick tests and serum-specific IgE. Furthermore, the inflammatory process in the airways is very similar between allergic and non-allergic asthma, with increased T-helper type 2 (Th2) cells, mast cell activation and infiltration of eosinophils. This pattern of inflammation is associated with a similar expression of inflammatory mediators, including Th2 cytokines and eosinophilotactic chemokines. There is increasing evidence that microbial superantigens, particularly Staphylococcal enterotoxins are important in amplifying inflammation in atopic dermatitis and chronic rhinosinusitis, in atopic and non-atopic patients. Superantigens may also be important in intrinsic asthma as airway epithelial cells may be colonized by Staphylococci and other superantigen-producing microbes. Superantigens produced locally in the airways may lead to class switching of local B cells, resulting in polyclonal IgE production in the airways and also specific IgE against the superantigen (which functions as a 'superallergen'). This leads to sensitization of mast cells, which can be activated by the usual asthma triggers, such as exercise. Superantigens also cause clonal expansion of T cells, resulting in increased Th2 cells and CD8(+) cells, while suppressing regulatory T cells. Superantigens may also reduce responsiveness to corticosteroids, resulting in more severe asthma. Finally, cytotoxic autoantibodies may also be implicated as IgG antibodies directed against epithelial proteins, such as cytokeratin-18, have been detected in intrinsic asthma, possibly as a result of epithelial damage and this may make epithelial cells more susceptible to microbial colonization. The therapeutic implications are that antibodies against local IgE and microbial superantigens or antibiotic therapy to eradicate the relevant superantigen-producing microorganisms may improve the efficacy of conventional therapy with corticosteroids.

Fc(epsilon)RI and FcgammaRIII/CD16 differentially regulate atopic dermatitis in mice

The high-affinity IgE receptor Fc(epsilon)RI and, in some models, the low-affinity IgG receptor Fc(epsilon)RIIII/CD16 play an essential role in allergic diseases. In human skin, they are present on APCs and effector cells recruited into the inflamed dermis. FcRgamma is a subunit shared, among other FcRs, by Fc(epsilon)RI and CD16 and is essential to their assembly and signal transduction. Using an experimental model reproducing some features of human atopic dermatitis and specific FcR-deficient mice, we have herein delineated the respective contribution of Fc(epsilon)RIand Fc(epsilon)RIII/CD16 to the pathology. We demonstrate that symptoms of atopic dermatitis are completely absent in FcRgamma-deficient animals but only partially inhibited in either Fc(epsilon)RI- or FcgammaRIII/CD16-deficient animals. Absence or attenuation of the pathology is correlated to increased skin expression of regulatory IL-10 and Foxp3. While Fc(epsilon)RI controls both Th1 and Th2 skin response, mast cell recruitment into draining lymph nodes and IgE production, CD16 regulates only Th2 skin response, as well as T cell proliferation and IgG1 production. This isotype-specific regulation by the cognate FcR is associated to a differential regulation of IL-4 and IL-21 expression in the draining lymph nodes. Fc(epsilon)RIand CD16 thus contribute to atopic dermatitis but differentially regulate immune responses associated with the disease. Targeting both IgE/Fc(epsilon)RI and IgG/CD16 interactions might represent an efficient therapeutic strategy for allergic diseases.

CD8+ T cells in asthma: friend or foe?

While it is well established that CD4(+) T lymphocytes play a crucial role in the initiation, progression and persistence of asthma, the role of CD8(+) T cells is less understood. CD8(+) T cells form functionally similar subsets which exhibit similar cytokine profiles as Th1 and Th2 cells, known as Tc1 and Tc2. Evidence from animal studies suggest that CD8(+) T cells are capable of regulating IgE production through the induction of IL-12 and IL-18 production in dendritic cells, and that CD8(+) T cells may act to moderate Th2 polarisation within the localised lymph nodes during allergic sensitisation. Such findings have led to the suggestion that Th1 polarising, CD8(+) T cell-inducing vaccines would inhibit the development of airway hyperresponsiveness (AHR) and Th2 cell infiltration. Despite these positive findings, the role of CD8(+) T cells within the lung remains poorly understood. While CD8(+) T cells, particularly those expressing the Tc1 phenotype, are capable of moderating inflammation and suppressing AHR, it has been postulated that Tc2 CD8(+) T cells predominate within established asthma and may act to amplify the inappropriate immune response which defines the condition. Within the clinic, the association between CD8(+) T cells and asthma is almost universally defined as injurious, further suggesting a prejudicial role for these cells within the established disease. CD8(+) T cells may be a valuable potential target for therapeutic intervention, either by potentiating their regulatory effects prior to the development of sensitisation, or through suppressing their pro-inflammatory properties within established atopy.

New drugs targeting Th2 lymphocytes in asthma

Asthma represents a profound worldwide public health problem. The most effective anti-asthmatic drugs currently available include inhaled beta2-agonists and glucocorticoids and control asthma in about 90-95% of patients. The current asthma therapies are not cures and symptoms return soon after treatment is stopped even after long term therapy. Although glucocorticoids are highly effective in controlling the inflammatory process in asthma, they appear to have little effect on the lower airway remodelling processes that appear to play a role in the pathophysiology of asthma at currently prescribed doses. The development of novel drugs may allow resolution of these changes. In addition, severe glucocorticoid-dependent and resistant asthma presents a great clinical burden and reducing the side-effects of glucocorticoids using novel steroid-sparing agents is needed. Furthermore, the mechanisms involved in the persistence of inflammation are poorly understood and the reasons why some patients have severe life threatening asthma and others have very mild disease are still unknown. Drug development for asthma has been directed at improving currently available drugs and findings new compounds that usually target the Th2-driven airway inflammatory response. Considering the apparently central role of T lymphocytes in the pathogenesis of asthma, drugs targeting disease-inducing Th2 cells are promising therapeutic strategies. However, although animal models of asthma suggest that this is feasible, the translation of these types of studies for the treatment of human asthma remains poor due to the limitations of the models currently used. The myriad of new compounds that are in development directed to modulate Th2 cells recruitment and/or activation will clarify in the near future the relative importance of these cells and their mediators in the complex interactions with the other pro-inflammatory/anti-inflammatory cells and mediators responsible of the different asthmatic phenotypes. Some of these new Th2-oriented strategies may in the future not only control symptoms and modify the natural course of asthma, but also potentially prevent or cure the disease.

Immunology of asthma and chronic obstructive pulmonary disease

Asthma and chronic obstructive pulmonary disease (COPD) are both obstructive airway diseases that involve chronic inflammation of the respiratory tract, but the type of inflammation is markedly different between these diseases, with different patterns of inflammatory cells and mediators being involved. As described in this Review, these inflammatory profiles are largely determined by the involvement of different immune cells, which orchestrate the recruitment and activation of inflammatory cells that drive the distinct patterns of structural changes in these diseases. However, it is now becoming clear that the distinction between these diseases becomes blurred in patients with severe asthma, in asthmatic subjects who smoke and during acute exacerbations. This has important implications for the development of new therapies.

Omalizumab (Xolair) in patients with steroid-resistant asthma: lessons to be learnt

Very severe asthma and local pulmonary steroid resistance causes major problems for patients, physicians and the health system at large. It usually results in multiple admissions to hospital and high morbidity. Omalizumab was used to treat such patients with success. However, in doing so, it raised a number of issues relating to the best methods of using this treatment in such patients.

Anti-IgE and other antibody targets in asthma

Asthma is a heterogeneous disorder of unknown etiology that manifests as recurrent episodes of coughing, wheezing, and breathlessness. These symptoms are often debilitating and exacerbations usually are unexpected, resulting in work or school absences, limitations in activity, reduced quality of life, and personal and economic hardships. Over the past several decades, a great deal has been learned about asthma pathophysiology, and currently available therapies have revolutionized asthma treatment. However, asthma remains a global public health problem, and the hope is that newer therapies targeting specific biological mediators of asthma, particularly antibody-mediated therapies, offer exciting new modes to the control of this disease. We will review some of these therapies, with the majority of attention devoted to anti-IgE therapy which has been approved for treatment of adult and childhood asthma by the US Food and Drug Administration (FDA) since 2003.