Airway Eosinophilopoietic and Autoimmune Mechanisms of Eosinophilia in Severe Asthma

Immunotherapeutic implications on targeting the cytokines produced in rhinovirus-induced immunoreactions

Rhinovirus is a widespread virus associated with several respiratory diseases, especially asthma exacerbation. Currently, there are no accurate therapies for rhinovirus. Encouragingly, it is found that during rhinovirus-induced immunoreactions the levels of certain cytokines in patients' serum will alter. These cytokines may have pivotal pro-inflammatory or anti-inflammatory effects via their specific mechanisms. Thus far, studies have shown that inhibitions of cytokines such as IL-1, IL-4, IL-5, IL-6, IL-13, IL-18, IL-25, and IL-33 may attenuate rhinovirus-induced immunoreactions, thereby relieving rhinovirus infection. Furthermore, such therapeutics for rhinovirus infection can be applied to viruses of other species, with certain practicability.

4-Octyl Itaconate Alleviates Airway Eosinophilic Inflammation by Suppressing Chemokines and Eosinophil Development

4-Octyl itaconate (4-OI) is a derivative of the Krebs cycle-derived metabolite itaconate and displays an array of antimicrobial and anti-inflammatory properties through modifying cysteine residues within protein targets. We have found that 4-OI significantly reduces the production of eosinophil-targeted chemokines in a variety of cell types, including M1 and M2 macrophages, Th2 cells, and A549 respiratory epithelial cells. Notably, the suppression of these chemokines in M1 macrophages was found to be NRF2-dependent. In addition, 4-OI can interfere with IL-5 signaling and directly affect eosinophil differentiation. In a model of eosinophilic airway inflammation in BALB/c mice, 4-OI alleviated airway resistance and reduced eosinophil recruitment to the lungs. Our findings suggest that itaconate derivatives could be promising therapeutic agents for the treatment of eosinophilic asthma.

Pathobiology of Type 2 Inflammation in Asthma and Nasal Polyposis

Asthma and nasal polyposis often coexist and are frequently intertwined by tight pathogenic links, mainly consisting of the cellular and molecular pathways underpinning type 2 airway inflammation. The latter is characterized by a structural and functional impairment of the epithelial barrier, associated with the eosinophilic infiltration of both the lower and upper airways, which can be driven by either allergic or non-allergic mechanisms. Type 2 inflammatory changes are predominantly due to the biological actions exerted by interleukins 4 (IL-4), 13 (IL-13), and 5 (IL-5), produced by T helper 2 (Th2) lymphocytes and group 2 innate lymphoid cells (ILC2). In addition to the above cytokines, other proinflammatory mediators involved in the pathobiology of asthma and nasal polyposis include prostaglandin D₂ and cysteinyl leukotrienes. Within this context of 'united airway diseases', nasal polyposis encompasses several nosological entities such as chronic rhinosinusitis with nasal polyps (CRSwNP) and aspirin-exacerbated respiratory disease (AERD). Because of the common pathogenic origins of asthma and nasal polyposis, it is not surprising that the more severe forms of both these disorders can be successfully treated by the same biologic drugs, targeting many molecular components (IgE, IL-5 and its receptor, IL-4/IL-13 receptors) of the type 2 inflammatory trait.

Translating the biology of β common receptor-engaging cytokines into clinical medicine

The family of cytokines that comprises IL-3, IL-5, and GM-CSF was discovered over 30 years ago, and their biological activities and resulting impact in clinical medicine has continued to expand ever since. Originally identified as bone marrow growth factors capable of acting on hemopoietic progenitor cells to induce their proliferation and differentiation into mature blood cells, these cytokines are also recognized as key mediators of inflammation and the pathobiology of diverse immunologic diseases. This increased understanding of the functional repertoire of IL-3, IL-5, and GM-CSF has led to an explosion of interest in modulating their functions for clinical management. Key to the successful clinical translation of this knowledge is the recognition that these cytokines act by engaging distinct dimeric receptors and that they share a common signaling subunit called β-common or βc. The structural determination of how IL-3, IL-5, and GM-CSF interact with their receptors and linking this to their differential biological functions on effector cells has unveiled new paradigms of cell signaling. This knowledge has paved the way for novel mAbs and other molecules as selective or pan inhibitors for use in different clinical settings.

Airway autoantibodies are determinants of asthma severity

BACKGROUND

Local airway autoimmune responses may contribute to steroid dependence and persistent eosinophilia in severe asthma. Auto-IgG antibodies directed against granule proteins such as eosinophil peroxidase (EPX), macrophage scavenger receptor with collagenous structure (MARCO) and nuclear/extranuclear antigens (antinuclear antibodies (ANAs)) have been reported. Our objective was to describe the prevalence and clinical characteristics of asthmatic patients with airway autoreactivity, and to assess if this could be predicted from clinical history of autoreactivity.

METHODS

We analysed anti-EPX, anti-MARCO and ANAs in 218 sputum samples collected prospectively from 148 asthmatic patients, and evaluated their association with lung function parameters, blood/airway inflammation, severity indices and exacerbations. Additionally, 107 of these patients consented to fill out an autoimmune checklist to determine personal/family history of systemic autoimmune disease and symptoms.

RESULTS

Out of the 148 patients, 59 (40%) were anti-EPX IgG+, 53 (36%) were anti-MARCO IgG+ and 64 out of 129 (50%) had ≥2 nuclear/extranuclear autoreactivities. A composite airway autoreactivity score (CAAS) demonstrated that 82 patients (55%) had ≥2 airway autoreactivities (considered as CAAS+). Increased airway eosinophil degranulation (OR 15.1, 95% CI 1.1-199.4), increased blood leukocytes (OR 3.5, 95% CI 1.3-10.1) and reduced blood lymphocytes (OR 0.19, 95% CI 0.04-0.84) predicted CAAS+. A third of CAAS+ patients reported an exacerbation, associated with increased anti-EPX and/or anti-MARCO IgG (p<0.05). While no association was found between family history or personal diagnosis of autoimmune disease, 30% of CAAS+ asthmatic patients reported sicca symptoms (p=0.02). Current anti-inflammatory (inhaled/oral corticosteroids and/or adjunct anti-interleukin-5 biologics) treatment does not attenuate airway autoantibodies, irrespective of eosinophil suppression.

CONCLUSION

We report 55% of moderate-severe asthmatic patients to have airway autoreactivity that persists despite anti-inflammatory treatment and is associated with exacerbations.

Airway autoimmunity, asthma exacerbations, and response to biologics

Biologic therapies in asthma are indicated in severe disease, and they are directed against specific inflammatory modulators that contribute to pathogenesis and severity. Currently approved biologics target T2 cytokines (IgE, IL-5, IL-4/IL-13, and TLSP) and have demonstrated efficacy in clinical outcomes such as exacerbation rate and oral corticosteroid dose reductions, blood and airway eosinophil depletion, and lung function improvement. However, a proportion of these patients may show inadequate responses to biologics, with either initial lack of improvement or clinical and functional worsening after an optimal initial response. Exacerbations while on a biologic may be due to several reasons, including imprecise identification of the dominant effector pathway contributing to severity, additional inflammatory pathways that are not targeted by the biologic, inaccuracies of the biomarker used to guide therapy, inadequate dosing schedules, intercurrent airway infections, anti-drug neutralizing antibodies, and a novel phenomenon of autoimmune responses in the airways interfering with the effectiveness of the monoclonal antibodies. This review, illustrated using case scenarios, describes the underpinnings of airway autoimmune responses in driving exacerbations while patients are being treated with biologics, device a strategy to evaluate such exacerbations, an algorithm to switch between biologics, and perhaps to consider two biologics concurrently.

Eosinophilic inflammation: An Appealing Target for Pharmacologic Treatments in Severe Asthma

Severe asthma is characterized by different endotypes driven by complex pathologic mechanisms. In most patients with both allergic and non-allergic asthma, predominant eosinophilic airway inflammation is present. Given the central role of eosinophilic inflammation in the pathophysiology of most cases of severe asthma and considering that severe eosinophilic asthmatic patients respond partially or poorly to corticosteroids, in recent years, research has focused on the development of targeted anti-eosinophil biological therapies; this review will focus on the unique and particular biology of the eosinophil, as well as on the current knowledge about the pathobiology of eosinophilic inflammation in asthmatic airways. Finally, current and prospective anti-eosinophil therapeutic strategies will be discussed, examining the reason why eosinophilic inflammation represents an appealing target for the pharmacological treatment of patients with severe asthma.

Cinnamomum cassia (L.) J.Presl Alleviates Allergic Responses in Asthmatic Mice via Suppression of MAPKs and MMP-9

The prevalence of asthma is gradually increasing, and endangers human health. Many therapeutic agents have been developed to address this concern. Cinnamomum cassia (L.) J.Presl is a traditional herbal remedy in China, Japan, and Korea and used mainly to control common cold, cough, pneumonitis and fever in Donguibogam, a medical encyclopedia of Korea. Therefore, we investigated whether C. cassia (L.) J.Presl extract (CCE) confers protective effects on asthma model induced by ovalbumin (OVA). The animals were received intraperitoneal administration of OVA on day 1 and 14, and then subjected to OVA inhalation from day 21–23. They were orally treated CCE (30 and 100 mg/kg) from day 18–23. CCE administration decreased allergic responses, including airway hyperresponsiveness, eosinophilia, inflammatory cytokine production, and immunoglobulin E in OVA-exposed mice, along with the decline in inflammatory cell count and mucus secretion in respiratory tract. Additionally, CCE suppressed MAPK phosphorylation and MMP-9 expression in OVA-exposed mice. Overall, CCE treatment attenuated allergic responses induced by OVA exposure, which may be connected to the suppression of MAPK phosphorylation.

Novel Biological Therapies for Severe Asthma Endotypes

Severe asthma comprises several heterogeneous phenotypes, underpinned by complex pathomechanisms known as endotypes. The latter are driven by intercellular networks mediated by molecular components which can be targeted by specific monoclonal antibodies. With regard to the biological treatments of either allergic or non-allergic eosinophilic type 2 asthma, currently available antibodies are directed against immunoglobulins E (IgE), interleukin-5 (IL-5) and its receptor, the receptors of interleukins-4 (IL-4) and 13 (IL-13), as well as thymic stromal lymphopoietin (TSLP) and other alarmins. Among these therapeutic strategies, the best choice should be made according to the phenotypic/endotypic features of each patient with severe asthma, who can thus respond with significant clinical and functional improvements. Conversely, very poor options so far characterize the experimental pipelines referring to the perspective biological management of non-type 2 severe asthma, which thereby needs to be the focus of future thorough research.

Vitamin D Attenuates Airway Inflammation in Asthmatic Guinea Pigs Using Mammalian Target of Rapamycin-Mediated Autophagy

The purpose of this experiment is to find out the function of Vitamin D (VD) in airway inflammation in asthmatic guinea pigs by regulating mammalian target of rapamycin (mTOR)-mediated autophagy. A total of 40 male guinea pigs were randomly assigned into the Con group, the ovalbumin (OVA)-sensitized group, the VD group, the VD + dimethyl sulfoxide group, and the VD + rapamycin (mTOR inhibitor) group. Then, serum from all groups was harvested for the measurement of immunoglobulin E (IgE), interleukin (IL)-4, and IL-5 levels. Next, bronchoalveolar lavage fluid was collected for cell counting. Moreover, lung tissues were extracted to assess levels of p-mTOR and autophagy factors (LC3B, Beclin1, Atg5, and P62). Compared with the Con group, the OVA group showed elevated levels of IgE, IL-4, and IL-5, increased contents of eosinophils, neutrophil, and lymphocytes, and declined monocytes. And the VD group improved inflammatory reactions in the guinea pigs. Besides, the OVA group showed lower levels of p-mTOR and P62 and higher autophagy levels than the Con group, while the VD group had opposite results. Rapamycin annulled the suppressive role of VD to airway inflammation in asthmatic guinea pigs. VD might inhibit OVA-induced airway inflammation by inducing mTOR activation and downregulating autophagy in asthmatic guinea pigs.

Heterogeneous Response of Airway Eosinophilia to Anti-IL-5 Biologics in Severe Asthma Patients

Many questions concerning responders (R) and nonresponders (NR) in severe eosinophilic asthma (SEA) after blocking the IL-5 (interleukin 5) pathway are still not clear, especially regarding the early parameters of response to biologics in personalized treatment strategies. We evaluated 17 SEA patients treated with anti-IL-5 biologics (16 patients mepolizumab, one patient benralizumab) before the introduction of biologics, and at a week 16 follow-up. Clinical, cellular and immunological parameters in peripheral blood were measured in R and NR. Sputum induction with the measurement of cellular and immunological parameters was performed at 16 weeks only. There were 12 R and 5 NR to biologics. After 16 weeks, there was a significant improvement in percentages of FEV1 (p = 0.001), and asthma control test (ACT) (p = 0.001) in the R group, but not in NR. After 16 weeks, the eosinophils in induced sputum were 27.0% in NR and 4.5% in R (p = 0.05), with no difference in IL-5 concentrations (p = 0.743). Peripheral eosinophilia decreased significantly in NR (p = 0.032) and R (p = 0.002). In patients with SEA on anti-IL-5 therapy, there was a marked difference in airway eosinophilic inflammation between R and NR already at 16 weeks, after anti-IL-5 introduction.

Adipose-Derived Mesenchymal Stem Cell-Derived Exosomal miR-301a-3p Regulates Airway Smooth Muscle Cells During Asthma by Targeting STAT3

Background

Asthma is a chronic inflammatory disease featured by inflammation and remodeling of airway. Adipose-derived mesenchymal stem cell (ADSCs)-derived exosomal miRNAs have been suggested as promising therapeutic manners for diseases.

Methods

ADSCs and airway smooth muscle cells (ASMCs) were isolated from SD rats. Flow cytometry was conducted to detect the surface biomarkers of isolated cells. Exosomes were extracted by sequentially centrifuge method and identified by Western blotting and nanoparticle tracking analysis (NTA). Uptake of exosomes by ASMCs was detected by confocal assay. ASMCs were treated with platelet-derived growth factor-BB (PDGF-BB) to mimic cell remodeling and inflammation. Cell counting 8 (CCK-8), Transwell, and flow cytometry were performed to determine the viability, migration, and apoptosis of ASMCs. Release of inflammatory factors was detected by enzyme-linked immunosorbent assay (ELISA). Levels of RNAs and proteins were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay. Interaction between miR-301a-3p and signal transducer and activator of transcription 3 (STAT3) was determined by luciferase reporter gene assay. The effect of Exosomal miR-301a-3p was analyzed in ovalbumin (OVA)-induced asthma mouse model.

Results

ADSCs-derived exosomes could be effectively internalized by ASMCs. Exosomal miR-301a-3p notably suppressed the PDGF-BB-stimulated proliferation and migration of ASMCs, and enhanced apoptosis, as well as decreased the secretion of inflammatory factors. MiR-301a-3p directly targeted the 3ʹUTR region of STAT3. STAT3 overexpression reversed the suppressive effects of exosomal miR-301a-3p on ASMCs under PDGF-BB stimulation. The expression of miR-301a-3p and STAT3 was negative correlation in specimen from patients with asthma. Exosomal miR-301a-3p inhibited OVA-induced lung injury by targeting STAT3 in mice.

Conclusion

This study exposed that exosomal miR-301a-3p from ADSCs could effectively alleviate PDGF-BB-stimulated remodeling and inflammation of ASMCs via targeting STAT3, presented ADSCs-derived exosomal miR-301a-3p as a promising therapeutic approach for asthma.

Reduction/elimination of blood eosinophils in severe asthma: should there be a safety consideration?

INTRODUCTION

Eosinophils play a central role in the inflammation of asthma and are the target of new biologic treatments for patients with severe asthma. Biologics targeting the IL-5 pathway have been shown to reduce asthma exacerbations, improve lung function, reduce oral corticosteroid use, and improve quality of life, accompanied by reduced or even eliminated blood eosinophils. Eosinophils have been associated with host protection and tumor growth, raising potential concerns about the consequences of these long-term therapies that reduce or eliminate them.

AREAS COVERED

In this review, we explore the current safety profile of biologics regarding the impact they may have on blood eosinophils, trying to answer the question about any safety consideration.

EXPERT OPINION

Eosinophils have been associated with host protection and tumor growth, raising potential concerns about the consequences of long-term therapies that reduce or eliminate these blood cells.

Molecular markers of type 2 airway inflammation are similar between eosinophilic severe asthma and eosinophilic chronic obstructive pulmonary disease

BACKGROUND

Airway and systemic eosinophilia are important treatable traits in both severe asthma and COPD. The molecular basis of eosinophilia in COPD is poorly understood but could involve type 2 cytokines (IL5, IL13) and prostaglandin D₂ (PGD₂ ).

METHODS

This study included non-obstructive airways disease (OAD) controls (n = 19), a COPD cohort (n = 96) and a severe asthma cohort (n = 84). Demographics, exacerbation history, disease impact (SGRQ) and spirometry were assessed. Participants were categorized as eosinophilic using either sputum eosinophil proportion (≥3%) or blood eosinophil count (≥300/μL). Sputum type 2 inflammatory measures included PGD₂ by ELISA and gene expression (qPCR) of IL5, IL13 and the haematopoietic PGD₂ synthase (HPGDS).

RESULTS

Type 2 markers did not differ across groups except HPGDS mRNA which was highest in non-OAD controls and lowest in COPD. IL5 and IL13 mRNA and PGD₂ levels were significantly increased in eosinophilic vs non-eosinophilic severe asthma but did not differ between eosinophilic COPD and eosinophilic severe asthma or non-eosinophilic COPD. HPGDS expression was higher in eosinophilic severe asthma compared with eosinophilic COPD. Results were similar using sputum or blood eosinophil cut-offs. Sputum IL5 and IL13 were highly intercorrelated in severe asthma (r = 0.907, p < 0.001) and COPD (r = 0.824, p < 0.001), were moderately correlated with sputum eosinophils in severe asthma (IL5 r = 0.440, p < 0.001; IL13 r = 0.428, p < 0.001) and were weakly correlated in COPD (IL5 r = 0.245, p < 0.05; IL13 r = 0.317, p < 0.05).

CONCLUSIONS

Molecular markers of type 2 airway inflammation do not differ between eosinophilic asthma and eosinophilic COPD; however, the relationship between eosinophilia and type 2 airway markers appears weaker in COPD than in severe asthma.

Biologics in severe asthma

Asthma is a chronic airway disease consisting of usually variable airflow limitation and bronchial hyperresponsiveness. Many different phenotypes characterize the clinical expression of asthma, determined by heterogeneous inflammatory patterns driven by distinct cellular and molecular mechanisms known as endotypes. Inside the complex framework of asthma pathobiology, several molecules such as immunoglobulins E (IgE), pro-inflammatory cytokines and their receptors can be targeted by present and future biological treatments of severe asthma. Within this context, already registered monoclonal antibodies including omalizumab, mepolizumab, reslizumab, benralizumab and dupilumab may interfere at various levels with the pathogenic pathways responsible for type-2 airway inflammation. In particular, these drugs target IgE (omalizumab), IL-5 (mepolizumab and reslizumab), IL-5 receptor (benralizumab) and IL-4/IL-13 receptors (dupilumab), respectively. Moreover, other biological therapies are under evaluation in pre-marketing trials, mainly aimed to assess the efficacy and safety of monoclonal antibodies directed against innate cytokines such as IL-33 and thymic stromal lymphopoietin (TSLP). Among current and perspective therapeutic approaches, clinicians can choose phenotype/endotype-driven tailored treatments, able to pursue an effective control of difficult to treat type-2 asthma.

Molecular Targets for Biological Therapies of Severe Asthma

Asthma is a heterogeneous respiratory disease characterized by usually reversible bronchial obstruction, which is clinically expressed by different phenotypes driven by complex pathobiological mechanisms (endotypes). Within this context, during the last years several molecular effectors and signalling pathways have emerged as suitable targets for biological therapies of severe asthma, refractory to standard treatments. Indeed, various therapeutic antibodies currently allow to intercept at different levels the chain of pathogenic events leading to type 2 (T2) airway inflammation. In addition to pro-allergic immunoglobulin E (IgE), that chronologically represents the first molecule against which an anti-asthma monoclonal antibody (omalizumab) was developed, today other targets are successfully exploited by biological treatments of severe asthma. In particular, pro-eosinophilic interleukin 5 (IL-5) can be targeted by mepolizumab or reslizumab, whereas benralizumab is a selective blocker of IL-5 receptor. Moreover, dupilumab behaves as a dual receptor antagonist of pleiotropic interleukins 4 (IL-4) and 13 (IL-13). Besides these drugs that are already available in medical practice, other biologics are under clinical development such as those targeting innate cytokines, also including the alarmin thymic stromal lymphopoietin (TSLP), which plays a key role in the pathogenesis of type 2 asthma. Therefore, ongoing and future biological therapies are significantly changing the global scenario of severe asthma management. These new therapeutic options make it possible to implement phenotype/endotype-specific treatments, that are delineating personalized approaches precisely addressing the individual traits of asthma pathobiology. Such tailored strategies are thus allowing to successfully target the immune-inflammatory responses underlying uncontrolled T2-high asthma.

Sevoflurane modulates AQPs (1,5) expression and endoplasmic reticulum stress in mice lung with allergic airway inflammation

Sevoflurane was found to show protective roles in mice with asthma, however, the mechanism of which needs further exploring. Aquaporins (AQPs) have been demonstrated to be involved in the pathogenesis of asthma, while endoplasmic reticulum stress has been reported to be related to many inflammatory diseases and involved in protein processing, including AQPs. The present study aimed to determine the role of sevoflurane in AQPs (AQP1,3,4,5) expression in mice with allergic airway inflammation and the probable mechanism. The increased number of inflammatory cells infiltrating the lung tissue, and the elevated levels of tumor necrosis factor-α (TNF-α) and interleukin (IL) 13 (IL-13) were all decreased after sevoflurane treatment (all P<0.05). Meanwhile, mRNA levels of AQP1 and AQP5 but not AQP3 and AQP4 were decreased in ovalbumin (OVA)-induced allergic mice lung. Both the decreased mRNA expression and protein levels of AQP1 and AQP5 in allergic lung tissues were reversed by sevoflurane treatment. Furthermore, we established that sevoflurane inhibited the OVA-induced protein increase in the endoplasmic reticulum (ER) stress markers BiP and C/EBP homologous protein (CHOP). Collectively, these findings suggested that sevoflurane modulated the expression and protein level of AOPs (AQP1, AQP5) as well as inhibited ER stress response in OVA-induced allergic airway inflammation of mice.

Toll-Like Receptor Characterization Correlates with Asthma and Is Predictive of Diagnosis

Toll-like receptors (TLRs) play crucial roles in the recognition of invading pathogens and the immune system. However, the effect of TLRs in asthma is still not fully known. This study was performed to better understand the role of TLR signatures in asthma. Blood samples from case-control studies (study 1: 348 asthmas and 39 normal controls and validation study 2: 411 asthmas and 87 normal controls) were enrolled. The single-sample gene set enrichment analysis method was performed to quantify the abundance of 21 TLR signatures. Gene ontology analysis and pathway function analysis were conducted for functional analysis, and a protein-protein interaction network was constructed. The area under the curve (AUC) value was used to assess the diagnostic capacity. In this study, TLR2/TLR3/TLR4 pathway, MyD88-dependent/independent TLR pathway, positive regulation of TLR4 pathway, and TLR binding signatures were significantly higher in asthma. Functional analysis showed that biological processes and pathways were still involved in TLR cascades and TLR signaling pathway. Eleven hub TLR-related genes were identified, and further validation demonstrated that the combination of TLR-related genes was a good diagnostic biomarker for asthma (AUC = 0.8). Our study provided more insight into the underlying immune mechanism of how TLR signatures affected asthma. The use of the easy-to-apply TLR-related genes might represent a promising blood-based biomarker for early detection of asthma.

Sputum and serum autoantibody profiles and their clinical correlation patterns in COPD patients with and without eosinophilic airway inflammation

Background

Autoimmunity plays a role in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, the autoantibody responses and their clinical correlation patterns in COPD patients with and without airway eosinophilic inflammation are unknown. The aim of this study was to compare the autoantibody profiles and their clinical associations in stable COPD patients, stratified by airway inflammatory phenotypes.

Methods

Matched sputum and serum, obtained from 62 stable COPD patients and 14 age-matched controls, were assayed for the presence of IgG and IgM antibodies against 13 autoantigens using protein array. A sputum eosinophil count ≥3% was used as cut-off value to stratify COPD patients into eosinophilic and non-eosinophilic groups. Correlation network analysis was used to evaluate the correlation patterns among autoantibody and clinical variables in each group.

Results

There were no significant differences of clinical parameters and autoantibody levels between the two COPD groups. In non-eosinophilic COPD, sputum anti-CytochromeC_IgG and anti-Aggrecan_IgM were significantly higher than those in healthy controls, and prior exacerbation was positively associated with lung function and sputum anti-Collagen-IV_IgG. While in eosinophilic COPD, sputum/serum anti-heat shock protein (HSP)47_IgG, serum anti-HSP70_IgG and serum anti-Amyloid-beta_IgG were significantly lower than those in healthy controls, and no significant correlation between prior exacerbations and lung function was found. Differences were also observed in network hubs, with the network for non-eosinophilic COPD possessing 9 hubs comprising two lung function parameters and seven autoantibodies, compared with eosinophilic COPD possessing 12 hubs all comprising autoantibodies.

Conclusions

Autoantibody responses were heterogeneous and differentially correlated with the exacerbation risk and other clinical parameters in COPD patients of different inflammatory phenotypes. These findings provide useful insight into the need for personalized management for preventing COPD exacerbations.

Antibodies targeting the interleukin-5 signaling pathway used as add-on therapy for patients with severe eosinophilic asthma: a review of the mechanism of action, efficacy, and safety of the subcutaneously administered agents, mepolizumab and benralizumab

Introduction: Since the discovery of eosinophils in the sputum of asthmatic patients, several studies have offered evidence on their prominent role in the pathology and severity of asthma. Blood eosinophils, are a useful biomarker for therapy selection in severe asthma patients. IL-5 plays crucial role on maturation, activation, recruitment, and survival of eosinophils and constitutes an important therapeutic target for patients with severe uncontrolled eosinophilic asthma.Areas covered: This review focuses on the similarities and differences on mechanisms of action, efficacy, and safety, of two subcutaneously(SC) administered agents, the anti-interleukin(IL)-5 monoclonal antibody mepolizumab and the IL-5 receptor-α(IL-5Rα)-directed cytolytic monoclonal antibody benralizumab. All information used was collected from PubMed using keywords such as severe asthma, eosinophils, IL-5, airway inflammation, asthma exacerbations, mepolizumab, benralizumab, anti-IL5, and anti-IL5R either as single terms or in several combinations.Expert opinion: Both mepolizumab and benralizumab are promising for the treatment of severe eosinophilic asthma resulting in asthma control improvement and exacerbations reduction and can serve as steroid-sparing agents. However, since no head-to-head comparisons exist, it is unknown whether their different mechanisms of action might be related to different efficacy in specific patients' sub-phenotypes. Long-term clinical observations will provide real-world evidence regarding their lasting effectiveness and safety.

Role of Biologics in Asthma

Patients with severe uncontrolled asthma have disproportionally high morbidity and healthcare utilization as compared with their peers with well-controlled disease. Although treatment options for these patients were previously limited, with unacceptable side effects, the emergence of biologic therapies for the treatment of asthma has provided promising targeted therapy for these patients. Biologic therapies target specific inflammatory pathways involved in the pathogenesis of asthma, particularly in patients with an endotype driven by type 2 (T2) inflammation. In addition to anti-IgE therapy that has improved outcomes in allergic asthma for more than a decade, three anti-IL-5 biologics and one anti-IL-4R biologic have recently emerged as promising treatments for T2 asthma. These targeted therapies have been shown to reduce asthma exacerbations, improve lung function, reduce oral corticosteroid use, and improve quality of life in appropriately selected patients. In addition to the currently approved biologic agents, several biologics targeting upstream inflammatory mediators are in clinical trials, with possible approval on the horizon. This article reviews the mechanism of action, indications, expected benefits, and side effects of each of the currently approved biologics for severe uncontrolled asthma and discusses promising therapeutic targets for the future.

Interleukin-5 in the Pathophysiology of Severe Asthma

Interleukin-5 (IL-5) exerts a central pathogenic role in differentiation, recruitment, survival, and degranulation of eosinophils. Indeed, during the last years, significant advances have been made in our understanding of the cellular and molecular mechanisms underlying the powerful actions of IL-5 finalized to the induction, maintenance, and amplification of eosinophilic inflammation. Therefore, IL-5 is a suitable target for add-on biological therapies based on either IL-5 inhibition (mepolizumab, reslizumab) or blockade of its receptor (benralizumab). These modern treatments can result in being definitely beneficial for patients with severe type 2 (T2)-high eosinophilic asthma, refractory to conventional anti-inflammatory drugs such as inhaled and even systemic corticosteroids.