Type 2 immunity in asthma

Pollen Proteases Play Multiple Roles in Allergic Disorders

Allergic diseases are a major health concern worldwide. Pollens are important triggers for allergic rhinitis, conjunctivitis and asthma. Proteases released upon pollen grain hydration appear to play a major role in the typical immunological and inflammatory responses that occur in patients with allergic disorders. In this study, we aimed to identify specific proteolytic activity in a set of pollens with diverse allergenic potential. Diffusates from Chenopodium album, Plantago lanceolata and Eucalyptus globulus were added to a confluent monolayer of Calu-3 cells grown in an air-liquid interface system. We identified serine proteases and metalloproteinases in all pollen diffusates investigated. Proteases found in these pollen diffusates were shown to compromise the integrity of the lung epithelial barrier by disrupting transmembrane adhesion proteins E-cadherin, claudin-1 and Occludin, as well as, the cytosolic complex zonula occludens-1 (ZO-1) resulting in a time-dependent increase in transepithelial permeability. Tight junction disruption and increased transepithelial permeability facilitates allergen exposure to epithelial sub-layers contributing to the sensitization to a wide range of allergens. These pollen extracts also induced an increase in the release of interleukin 6 (IL-6) and interleukin 8 (IL-8) cytokines measured by flow cytometry possibly as a result of the activation of protease-activated receptors 2 (PAR-2).

A comparison of biologicals in the treatment of adults with severe asthma - real-life experiences

BACKGROUND

Anti-IgE (omalizumab) and anti-IL5/IL5R (reslizumab, mepolizumab and benralizumab) treatments are available for severe allergic and eosinophilic asthma. In these patients, studies have shown beneficial effects in oral corticosteroid use and exacerbations. The aim of this retrospective single-center study was to evaluate the effect of biological therapy on severe asthma and to compare different therapies.

METHODS

We collected and analysed results of anti-IL5/IL5R and anti-IgE therapies for asthma from January 2009 until October 2019 in specialized care. We compared number of exacerbations, asthma symptoms and use of per oral corticosteroids and antimicrobics because of asthma before and during biological therapy, and in a separate analysis need for per oral corticosteroids, antimicrobics or surgery due to upper respiratory tract diseases in asthmatics receiving biologicals. The analyses were done using the Chi square test, T-test or Mann-Whitney U -test, the Kruskall-Wallis test or the Wilcoxon test.

RESULTS

Of 64 patients, 40 used continuous per oral corticosteroid therapy prior to biological therapy. The mean daily dose of per oral corticosteroid was reduced in those with anti-IL5/IL5R therapy (- 3.0 mg, p = 0.02). The number of annual per oral corticosteroid courses decreased in both the anti-IL5/IL5R (- 2.8 courses, p < 0.05) and anti-IgE groups (- 1.3 courses, p < 0.05). The number of annual antibiotic courses (- 0.7 courses, p = 0.04) and total number of exacerbation events (- 4.4 events/year, p < 0.05) were reduced in the anti-IL5/IL5R group. In the 55 asthma patients analysed for upper respiratory tract findings, the results suggested a reduction in need for chronic rhinosinusitis surgery during biological therapy.

CONCLUSIONS

Results with biological therapies in this real-life clinical setting are comparable to those reported in clinical trials. Biological therapy reduces exacerbations and per oral corticosteroid use.

TRIAL REGISTRATION

NCT04158050, retrospectively registered 6.11.2019.

Sesamol Alleviates Airway Hyperresponsiveness and Oxidative Stress in Asthmatic Mice

Sesamol, isolated from sesame seeds (Sesamum indicum), was previously shown to have antioxidative, anti-inflammatory, and anti-tumor effects. Sesamol also inhibited lipopolysaccharide (LPS)-induced pulmonary inflammatory response in rats. However, it remains unclear how sesamol regulates airway inflammation and oxidative stress in asthmatic mice. This study aimed to investigate the efficacy of sesamol on oxidative stress and airway inflammation in asthmatic mice and tracheal epithelial cells. BALB/c mice were sensitized with ovalbumin, and received oral sesamol on days 14 to 27. Furthermore, BEAS-2B human bronchial epithelial cells were treated with sesamol to investigate inflammatory cytokine levels and oxidative responses in vitro. Our results demonstrated that oral sesamol administration significantly suppressed eosinophil infiltration in the lung, airway hyperresponsiveness, and T helper 2 cell-associated (Th2) cytokine expressions in bronchoalveolar lavage fluid and the lungs. Sesamol also significantly increased glutathione expression and reduced malondialdehyde levels in the lungs of asthmatic mice. We also found that sesamol significantly reduced proinflammatory cytokine levels and eotaxin in inflammatory BEAS-2B cells. Moreover, sesamol alleviated reactive oxygen species formation, and suppressed intercellular cell adhesion molecule-1 (ICAM-1) expression, which reduced monocyte cell adherence. We demonstrated that sesamol showed potential as a therapeutic agent for improving asthma.

Toward personalization of asthma treatment according to trigger factors

Asthma is a severe and chronic disabling disease affecting more than 300 million people worldwide. Although in the past few drugs for the treatment of asthma were available, new treatment options are currently emerging, which appear to be highly effective in certain subgroups of patients. Accordingly, there is a need for biomarkers that allow selection of patients for refined and personalized treatment strategies. Recently, serological chip tests based on microarrayed allergen molecules and peptides derived from the most common rhinovirus strains have been developed, which may discriminate 2 of the most common forms of asthma, that is, allergen- and virus-triggered asthma. In this perspective, we argue that classification of patients with asthma according to these common trigger factors may open new possibilities for personalized management of asthma.

Bronchiectasis in severe asthma: a distinct phenotype?

PURPOSE OF REVIEW

The presence of bronchiectasis has been described in about 30% of severe asthma patients. The coexistence of these two respiratory conditions poses new challenges from both clinical and research perspectives. We will review the available literature on this topic to discuss the existance of a specific clinical phenotype of asthma.

RECENT FINDINGS

Despite the paucity of literature, the presence of bronchiectasis with severe asthma is associated with older age, chronic bronchial expectoration, rhinosinusitis, more frequent and severe exacerbations, neutrophilic airway inflammation and poor response to usual treatment. Conversely, asthma features are also described in bronchiectasis patients even in the absence of an appropriate diagnosis of asthma. In both cases, there is some evidence supporting the use of bronchodilators, macrolides and respiratory physiotherapy, while the use of inhaled corticosteroids and antibiotics is controversial.

SUMMARY

Based on available evidence on the association between (severe) asthma and bronchiectasis, its pathophysiology, certain clinical aspects and prognosis are largely unclear. Although specific management appears to be required in most cases, in our opinion there is still insufficient evidence to consider it a distinct phenotype of severe asthma. Hopefully, future research will shed more light on this topic and define the best therapeutic approach.

Evolving phenotypes to endotypes: is precision medicine achievable in asthma?

Introduction: The development of biologic molecules led to a drastic change in the therapeutic approach to asthma. With the prospect of acting on different pathophysiological mechanisms of the disease, the idea of precision medicine was developed, in which a single molecule is able to modify a specific triggering mechanism. Thus, it seemed limiting to stop at the distinction of patients phenotypes and the concept of endotypes became more relevant in the therapeutic approach.Areas covered: This review deepened the topic of precision medicine through the transition from phenotyping to endotyping. We performed a review of the literature, preferring articles quoted in Medline and published in journals with an impact factor. Results showed that it is fundamental to take into consideration the role of biomarkers and the related therapies currently available for precision medicine.Expert opinion: The possible overlap of patients in different phenotypes requires a more precise classification, which considers endotypization. With the development of biological drugs able to modify and modulate some pathophysiological mechanisms of the disease, the theoretical concept of endotyping becomes practical, allowing the clinician to choose the specific mechanism to 'attack' in order to control the disease.

Huangqi-Fangfeng protects against allergic airway remodeling through inhibiting epithelial-mesenchymal transition process in mice via regulating epithelial derived TGF-β1

BACKGROUND

Long-term exposure to aeroallergens such as house dust mite (HDM) could result in airway inflammation and airway remodeling, characteristic features of allergic asthma. Huangqi-Fangfeng (HF), an important "couplet medicines" of Yu-Ping-Feng-San (YPFS), mediates allergen-induced airway inflammation in mice, but its role in the airway remodeling is not known.

PURPOSE

To evaluate the effects of HF on airway remodeling of allergic asthma in a murine model and to investigate the underlying mechanisms in vivo and in vitro.

METHODS

The main components of HF were analyzed by HPLC. The HDM-induced asthma mice model was established to study the effects of HF on airway inflammation and airway remodeling in vivo. Enhanced pause (Penh) index value was used as an indicator of airway hyper-reactivity. Bronchoalveolar lavage fluid (BALF) was processed for differential cell counting and determination of cytokines production. The lungs were fixed in 4% paraformaldehyde for histological examination after staining with H&E, trichrome and IHC. Production of interleukin (IL)-4, IL-5, IL-13, and transforming growth factor beta-1 (TGF-β1) in BALF and lung tissues, IgE in serum were measured by ELISAs. Expression of epithelial markers and mesenchymal markers were detected by immunohistochemistry and western blots. The effects of HF and its components on epithelial-mesenchymal transition (EMT) were detected in human bronchial epithelial cells (16HBE) treated with TGF-β1 and HDM.

RESULTS

The main components of Huangqi-Fangfeng detected by HPLC were Calycosin, Formononetin and Cimifugin. In HDM-induced allergic asthma mice model, respiratory exposure to HDM lead to airway hyperresponsiveness and thickening of the smooth muscle layer in the airway. TGF-β1 levels increased in mice airways while epithelial cells lost expression of E-cadherin and gained expression of the mesenchymal proteins N-cadherin, α-SMA and collagen І. These changes were relieved by treatment with HF. Furthermore, restored epithelial markers expression treated with individual components were also detectable in 16HBE cells.

CONCLUSION

These results demonstrated that Huangqi-Fangfeng protected against allergic airway remodeling through inhibiting epithelial-mesenchymal transition process in mice via regulating epithelial derived TGF-β1.

What have recent advances in therapy taught us about severe asthma disease mechanisms?

Introduction: Severe asthma still represents a worldwide challenge. The need for further treatment options has stimulated basic and pharmacological research to focus on the immune and inflammatory background of asthma. The new biologic drugs express the considerable advances in the field and besides providing a revolutionary treatment option for severe asthma, contribute themselves to better understand the pathophysiologic mechanisms they address, paving the way to new potential targets.Areas covered: A selective search on PubMed and Medline was performed, including the evidence on immunology of severe asthma published up to May 2019 by focusing on the immunological effects of biologic drugs underlying their clinical outcomes.Expert opinion: The recent pharmacological research in the field of biologics has represented an exceptional opportunity for exploring severe asthma mechanisms. However, some points deserve to be addressed by further investigation. Although in the absence of safety warnings so far, interfering with the immune system may raise some safety concerns, especially in the long-term use. Particularly when interacting with epithelial and innate immunity the selection of candidates probably deserves special caution. Also, whether biologics exert a true disease-modifying effect is not completely clear. As a direct practical implication, the optimal treatment duration is still controversial.

Mepolizumab for severe eosinophilic asthma: a real-world snapshot on clinical markers and timing of response

Background: Few studies have provided real-world evidence of mepolizumab efficacy and safety. We aimed to evaluate mepolizumab for severe eosinophilic asthma in daily clinical practice.Research design and methods: Patients included in the RINOVA (Interdisciplinary Network for the management of severe asthma in Veneto region, Italy) database were investigated. Blood eosinophil count, forced expiratory volume in 1 second, % of predicted (FEV1%), fractional exhaled nitric oxide (FeNO), asthma control test (ACT), oral steroid (OCS) intake, and exacerbation rate were evaluated during mepolizumab treatment.Results: 69 patients were enrolled (mean age: 55.1 years; 60.9% females). A significant improvement was detected at one month with respect to blood eosinophils (median level at baseline: 710/μl; -620/μl, p < 0,001), FEV1% (median value at baseline 87; range: 79-101; +4, p = 0.001) and ACT (median value at baseline 18; range: 14-20.5;+4, <0.001). A significant reduction of FeNO was observed six months after the treatment start, when the exacerbation rate and the mean OCS dose significantly decreased (respectively: Δ reduction -3; p < 0.001 and -5 mg; p < 0.001).Conclusions: Our study provides real-world evidence of mepolizumab safety and confirms its dramatic steroid sparing effect. The greatest clinical change (ACT and FEV1) was observed within the first month.

Serum levels of epithelial-derived mediators and interleukin-4/interleukin-13 signaling after bronchial challenge with Dermatophagoides pteronyssinus in patients with allergic asthma

Allergens are the main trigger that enhances airway type 2 inflammation, and the epithelium is the first line of defense that reacts to its exposure. Therefore, epithelial-derived mediators, such as interleukin (IL)-25, IL-33, thymic stromal lymphopoietin (TSLP) and ezrin, may play a role as alarmins in IL-4/IL-13 signaling in allergic asthma (AA). We investigated the serum levels of IL-25, IL-33, TSLP, ezrin, IL-4 and IL-13, after bronchial challenge with Dermatophagoides pteronyssinus in patients with AA. We examined 18 subjects: nine steroid-free stable patients with AA sensitized to D. pteronyssinus and nine non-atopic healthy subjects (HS). Bronchial allergen challenge was performed using inhaled D. pteronyssinus allergen. IL-4, IL-13, IL-25, IL-33, TSLP and ezrin levels in serum were measured by ELISA at two time points - before and 24 hours after bronchial allergen challenge. The serum levels of IL-25, TSLP and ezrin did not differ between AA and HS groups at baseline. However, after allergen exposure, significant increases in serum levels of IL-25, TSLP and ezrin were observed only in patients with AA. The serum level of IL-33 at baseline was significantly higher in the AA group compared with HS, but the allergen challenge did not provoke an increase of this cytokine in any group. IL-4 and IL-13 levels were significantly higher at baseline in the AA group compared with HS and, after allergen exposure, were significantly increased in the AA group, with no effect on HS. Thus, the epithelial-derived mediators IL-25, TSLP and ezrin, via IL4/IL13 signaling, enhance type 2 inflammation after bronchial challenge with D. pteronyssinus in AA.

Protective activity of mogroside V against ovalbumin-induced experimental allergic asthma in Kunming mice

We investigated the antiasthmatic effect of mogroside V (Mog V) in mice with ovalbumin (OVA)-induced asthma. Administration of Mog V effectively attenuated OVA-induced airway hyperresponsiveness and reduced the number of inflammatory cells in bronchoalveolar lavage fluid (BALF). Histological examination showed that Mog V reduced the inflammatory infiltration of the lungs in the asthmatic mice. ELISAs suggested that Mog V effectively decreased the levels of IL-4, IL-5, and IL-13 in BALF and serum levels of OVA-specific IgE and IgG1 in the asthmatic mice. A quantitative reverse-transcription PCR assay also indicated that Mog V decreased the mRNA levels of IL-17A, IL-23, and RORγt in the lungs of the asthmatic mice (the opposite effect on Foxp3 mRNA). Furthermore, Mog V significantly reduced the OVA-induced activation of NF-κB in the lungs. This study indicates that Mog V alleviates OVA-induced inflammation in airways, and this effect is associated with a reduction in NF-κB activation. PRACTICAL APPLICATIONS: A traditional Chinese medicine herb has been reported to have a strong curative effect on asthma in clinical practice. Siraitia grosvenorii is known in China as a functional food product with the ability to improve lung function. Mogroside V is a triterpene glycoside isolated from S. grosvenorii. Nonetheless, the antiasthmatic effect of mogroside V has not been evaluated yet. The aim of this study was to investigate the antiasthmatic activity of mogroside V in mice with chemically induced asthma. The data from this study will provide some scientific evidence supporting wider use of S. grosvenorii in functional foods.

Targeting eosinophils: severe asthma and beyond

Recent research in the field of bronchial asthma has mainly focused on eosinophilic disease phenotype. Several trials proved the efficacy and safety profile of eosinophils and interleukin (IL)-5 targeting molecules, currently approved for severe asthma and available on the market. They include mepolizumab and reslizumab, IL-5 blocking molecules, and benralizumab, targeting the IL-5 receptor and eliciting a NK cell-mediated antibody-dependent cellular cytotoxicity against eosinophils. Eosinophilic inflammation represents the common pathophysiological background of several conditions, providing the rationale for the use of the same biologics beyond asthma. Although with different evidence grade, from clinical trials to case reports, anti-IL-5 biologics have been investigated in eosinophilic granulomatosis with polyangitis, allergic bronchopulmonary aspergillosis, chronic eosinophilic pneumonia, nasal polyposis, hypereosinophilic syndrome, and eosinophilic esophagitis. However, non-negligible differences between asthma and other eosinophilic diseases, particularly in eosinophils homing (blood and/or tissues), target organs and thus clinical features, probably account for the different response to the same drug in different clinical conditions and highlights the need for tailoring the therapeutic approach by modulating the drug dose and/or by combination therapy with multiple drugs. The optimal safety and tolerability profile of anti-IL-5 drugs warrants further and larger experimental and real-life investigations, which are needed especially in the field of non-asthma eosinophilic diseases. This review aims at summarizing the rationale for the use of biologics in eosinophilic diseases and their mechanisms of action. The current efficacy and safety evidence about eosinophils and IL-5 targeting molecules in asthma and in eosinophilic conditions beyond bronchi is also discussed.

Effect of mepolizumab in severe eosinophilic asthma according to omalizumab eligibility

BACKGROUND

Patients with severe asthma can present with overlapping eosinophilic and allergic phenotypes, which makes it challenging when deciding which biologic therapy is most appropriate to reduce exacerbations and help achieve asthma control.

OBJECTIVE

This post hoc meta-analysis evaluated the efficacy of the licensed dose of mepolizumab (100 mg administered subcutaneously [SC]) versus placebo in patients with severe eosinophilic asthma (SEA), according to omalizumab eligibility and associated allergic characteristics.

METHODS

Data from two Phase 3 studies (MENSA [MEA115588/NCT01691521]; MUSCA [200862/NCT02281318]) were analyzed. Patients ≥12 years of age with SEA who experienced ≥2 exacerbations in the previous year received placebo, mepolizumab 100 mg SC or 75 mg intravenously, plus standard of care (high-dose inhaled corticosteroids and other controllers), every 4 weeks. Data from patients who received ≥1 dose placebo or mepolizumab 100 mg SC were used for this analysis. The primary endpoint was the rate of clinically significant exacerbations; other outcomes included forced expiratory volume in 1 s (FEV₁), Asthma Control Questionnaire (ACQ-5) score and quality of life measured using St George's Respiratory Questionnaire (SGRQ).

RESULTS

Rate reductions in clinically significant exacerbations with mepolizumab versus placebo were similar in omalizumab eligible and ineligible patients (57% vs 55%). FEV₁, ACQ-5 and SGRQ scores improved with mepolizumab versus placebo regardless of omalizumab eligibility, Immunoglobulin E levels, or atopic status.

CONCLUSION

This analysis indicated that mepolizumab 100 mg SC has clinical benefit in patients with blood eosinophil counts ≥150 cells/μL (or history of ≥300 cells/μL), regardless of allergic characteristics or omalizumab eligibility.

Current and future targeted therapies for severe asthma: Managing treatment with biologics based on phenotypes and biomarkers

Asthma is a respiratory disorder with considerable heterogeneity in aetiology, triggers, clinical characteristics and response to therapy. This diversity reflects different inflammatory pathways that can be subdivided into clinically similar categories called phenotypes, or pathogenically comparable groups called endotypes. In recent years, a great amount of research has been dedicated to the investigation and understanding of the heterogeneity of asthma pathophysiology and to the identification of treatable traits, biomarkers, mediators and therapeutic targets. Severe asthma is defined as an uncontrolled disease despite a maximal conventional therapeutic approach. While, to date, some target therapies showing improvements in lung function, asthma symptoms and a reduction of the annual rate of exacerbations in patients with severe asthma have been already approved, other treatments are currently being studied, specifically targeting Type 2 asthma. Further progress however, is still needed to tackle the molecular pathways for non-Type 2 asthma. The aim of the present narrative review is to discuss and examine the indication, mechanisms of action and therapeutic effects of currently available and emerging biologic agents for the treatment of severe asthma.

New horizons for the treatment of severe, eosinophilic asthma: benralizumab, a novel precision biologic

In the last decades, the increasing evidence concerning inflammation mechanisms underlying severe eosinophilic asthma has highlighted new potential therapeutic targets and has paved the way to new selective biologic drugs. Understanding the mechanism of action and the clinical outcomes of a particular drug along with the clinical and biological characteristics of the patient population for which that drug was intended may ensure appropriate selection of patients that will respond to that drug. Under this perspective, the present review will focus on the mechanisms of action and clinical evidence of benralizumab as a treatment option for severe eosinophilic asthma, in order to provide a concise overview and a reference for clinical practice. Benralizumab is a fully humanized afucosylated IgG1κ mAb that binds to an epitope on IL-5 Rα, and inhibits IL-5 signaling. Benralizumab also sustains antibody-directed cell-mediated cytotoxicity (ADCC) of eosinophils and basophils and consequently depletes IL-5Rα-expressing cells. As a result, it is responsible for a substantial depletion of blood, tissue, and bone marrow eosinophilia. This unique mechanism of action may account for a more complete and rapid action profile. Randomized clinical trials have demonstrated that benralizumab provides an optimal safety profile, and is able to significantly reduce asthma exacerbations, oral steroid intake, and to improve lung function. Some clinical predictors of enhanced clinical response to benralizumab have also been identified, including: a level of blood eosinophils ≥300 μL⁻¹, oral steroids use, the presence of nasal polyposis, FVC <65% of predicted, and a history of three or more exacerbations per year at baseline. These results can be helpful in identifying the best responder patients to benralizumab. As a step forward, the definition of the responder profile for each of the available biological treatment options will potentially support even more the pathway to precision medicine and the critical matching of the right drug with the right patient.

Sinus Infections, Inflammation, and Asthma

There is an important link between the upper and lower respiratory tracts whereby inflammation in one environment can influence the other. In acute rhinosinusitis, pathogen exposures are the primary driver for inflammation in the nose, which can exacerbate asthma. In chronic rhinosinusitis, a disease clinically associated with asthma, the inflammation observed is likely from a combination of an impaired epithelial barrier, dysregulated immune response, and potentially infection (or colonization) by specific pathogens. This review explores the associations between rhinosinusitis and asthma, with particular emphasis placed on the role of infections and inflammation.

Factors Beyond Lack of Antibody Govern Pulmonary Complications in Primary Antibody Deficiency

PURPOSE

Pulmonary complications occur frequently in primary antibody deficiency (PAD). While the impact of antibody deficiency may appear implicit for certain respiratory infections, immunoglobulin replacement therapy does not completely ameliorate pulmonary complications in PAD. Thus, there may be antibody-independent factors influencing susceptibility to respiratory disease in PAD, but these remain incompletely defined.

METHODS

We harnessed the multicenter US Immunodeficiency Network primary immunodeficiency registry to compare prevalence of asthma, bronchiectasis, interstitial lung disease (ILD), and respiratory infections between two forms of PAD: common variable immunodeficiency (CVID) and x-linked agammaglobulinemia (XLA). We also defined the clinical and immunological characteristics associated with ILD and asthma in CVID.

RESULTS

Asthma, bronchiectasis, ILD, pneumonia, and upper respiratory infections were more prevalent in CVID than XLA. ILD was associated with autoimmunity, bronchiectasis, and pneumonia as well as fewer B and T cells in CVID. Asthma was the most common chronic pulmonary complication and associated with lower IgA and IgM in CVID. Age of symptom onset or CVID diagnosis was unrelated with ILD or asthma.

CONCLUSION

Despite having less severe immunoglobulin deficiency than XLA, respiratory infections, ILD, and asthma were more common in CVID. Among CVID patients, ILD was associated with autoimmunity and reduced lymphocytes and asthma with lower immunoglobulins. Though our results are tempered by registry limitations, they provide evidence that factors beyond lack of antibody promote pulmonary complications in PAD. Efforts to understand how genetic etiology, nature of concurrent T cell deficiency, and propensity for autoimmunity shape pulmonary disease may improve treatment of PAD.

Myeloid C-type lectin receptors in skin/mucoepithelial diseases and tumors

Myeloid C‐type lectin receptors (CLRs), which consist of an extracellular carbohydrate recognition domain and intracellular signal transducing motif such as the immunoreceptor tyrosine‐based activation motif (ITAM) or immunoreceptor tyrosine‐based inhibitory motif (ITIM), are innate immune receptors primarily expressed on myeloid lineage cells such as dendritic cells (DCs) and Mϕs. CLRs play important roles in host defense against infection by fungi and bacteria by recognizing specific carbohydrate components of these pathogens. However, these immune receptors also make important contributions to immune homeostasis of mucosa and skin in mammals by recognizing components of microbiota, as well as by recognizing self‐components such as alarmins from dead cells and noncanonical non‐carbohydrate ligands. CLR deficiency not only induces hypersensitivity to infection, but also causes dysregulation of muco‐cutaneous immune homeostasis, resulting in the development of allergy, inflammation, autoimmunity, and tumors. In this review, we introduce recent discoveries regarding the roles of myeloid CLRs in the immune system exposed to the environment, and discuss the roles of these lectin receptors in the development of colitis, asthma, psoriasis, atopic dermatitis, and cancer. Although some CLRs are suggested to be involved in the development of these diseases, the function of CLRs and their ligands still largely remain to be elucidated.

Pharmacokinetics and pharmacodynamics of monoclonal antibodies for asthma treatment

INTRODUCTION

Asthma is a chronic inflammatory airway disease. It occurs in a 'severe' form in about 8-10% of asthmatic patients. In the last decade, the development of biological drugs (e.g. monoclonal antibodies) allowed to efficiently approach severe asthma. The current therapeutic targets available are mainly those related to TH2 inflammation. Areas covered: The main pharmacokinetic and pharmacodynamic characteristics of the monoclonal antibodies against IL-5, IL-5Ra, IL4-IL13, and IgE, that are currently marketed or understood for severe asthma are discussed in this paper. Expert opinion: The currently available biological drugs represent an excellent therapeutic add-on to traditional drugs, especially in replacing systemic corticosteroid therapies. The different pharmacokinetic and pharmacodynamic characteristics of the drugs, despite sometime sharing the same target, would allow a better personalization of the therapy, tailoring the treatment to the characteristics of the patient.

Severe Asthma and Allergy: A Pediatric Perspective

Severe asthma in children is associated with significant morbidity and lung function decline. It represents a highly heterogeneous disorder with multiple clinical phenotypes. As its management is demanding, the social and economic burden are impressive. Several co-morbidities may contribute to worsen asthma control and complicate diagnostic and therapeutic management of severe asthmatic patients. Allergen sensitization and/or allergy symptoms may predict asthma onset and severity. A better framing of "allergen sensitization" and understanding of mechanisms underlying progression of atopic march could improve the management and the long-term outcomes of pediatric severe asthma. This review focuses on the current knowledge about interactions between severe asthma and allergies.

Severe refractory asthma: current treatment options and ongoing research

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

Anti-IL-5 and IL-5Ra: Efficacy and Safety of New Therapeutic Strategies in Severe Uncontrolled Asthma

The current developments of the new biological drugs targeting interleukin 5 (IL-5) and IL-5 receptor allowed to expand the treatment options for severe hypereosinophilic asthma. Clinicians will then be able to choose between antibodies targeting either circulating IL-5 or its receptor expressed on eosinophils and basophils. The available clinical trials consistently reported favorable results about the reduction of exacerbations rate, improvement in quality of life, and sparing of the systemic steroid use, with a favorable safety profile. Two of these new drugs are administered subcutaneously, mepolizumab every 4 weeks and benralizumab every 8 weeks, whereas reslizumab is given intravenously monthly on a weigh-based dose. In the future, the research actions will be involved in the identification of a single biomarker or multiple biomarkers for the optimal choice of biological agents to be properly prescribed.