IL-1 receptor antagonist reduces endotoxin-induced airway inflammation in healthy volunteers

Innate immune responses are increased in children with acute asthma exacerbation

BACKGROUND

Little is known about the immune responses during acute asthma exacerbation. In this study, we examined immune responses in children following an acute asthma exacerbation.

METHODS

We evaluated pro-inflammatory cytokine levels and gene expression profiles in blood samples from pediatric patients admitted for acute asthma exacerbation. Viral PCR was performed to differentiate between viral or non-viral-associated exacerbations.

RESULTS

Following informed consent, clinical data were obtained from 20 children with asthma (median [interquartile range, IQR]: age 11.5 [8.0, 14.2]) years and 14 healthy age-matched controls (10.5 [7.0, 13.0]). Twelve had positive nasopharyngeal Polymerase chain reaction (PCR) for viral infection (11 rhinoviruses and 1 respiratory syncytial virus (RSV)). Nine were in the pediatric intensive care unit (PICU) and among them five required continuous positive airway pressure (CPAP). Mean (±SD) days on systemic steroids before drawing blood sample were 2.5 ± 1.6. Twelve had history of environmental allergies with 917 (274, 1396) IU/mL total IgE (median (IQR)). Compared with controls, IL-1RA and IL-10 levels were significantly increased and TNF-α significantly decreased in asthma subjects (p < .05 for all). RNA-seq analysis revealed 852 differentially expressed genes in subjects with asthma. Pathway analysis found upregulated genes and pathways involved in innate immune responses in subjects with asthma. Significantly reduced genes included pathways associated with T helper cell differentiation and activation.

CONCLUSIONS

In acute asthma exacerbation, innate immune pathways remained increased while adaptive immune responses related to T helper cells are blunted and are independent of trigger or asthma severity. Our novel findings highlight the need to identify new therapies to target persistent innate immune responses to improve outcomes in acute asthma.

Downregulation of otulin induces inflammasome activation in neutrophilic asthma

BACKGROUND

Neutrophilic asthma (NA) is a severe asthma phenotype associated with steroid resistance and IL-1β overproduction; however, the exact mechanism remains unclear. Moreover, the dysfunction of TNF-α signaling pathway, a regulator of IL-1β production, was associated with the deficiency of ovarian tumor protease deubiquitinase with linear linkage specificity (otulin) in autoimmune patients.

OBJECTIVE

We hypothesized that otulin downregulation in macrophages (Mφ) could trigger Mφ activation via the nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) inflammasome signaling pathway.

METHODS

We assessed the expressions of otulin in blood monocyte subsets from NA patients and in alveolar Mφ from NA mice. Additionally, we evaluated the functional consequences of otulin deficiency in bone marrow-derived Mφ. The effects of inhibiting receptor-interacting protein kinase (RIPK)-1 and RIPK-3 on neutrophils and group 3 innate lymphoid cells (ILC3s) were assessed in vitro and in vivo.

RESULTS

When comparing nonclassical monocytes, a significant downregulation of otulin in the intracellular components was observed in NA patients compared to healthy controls (P = .005). Moreover, isolated alveolar Mφ from the NA mice exhibited lower otulin expression compared to those from control mice. After otulin knockdown in bone marrow-derived Mφ, we observed spontaneous IL-1β production depending on NLRP3 inflammasome. Moreover, the infiltrated neutrophils and ILC3s were significantly decreased by combined treatment of RIPK-1 and RIPK-3 inhibitors through blocking IL-1β release in NA.

CONCLUSIONS

IL-1β overproduction caused by a deficiency of otulin, an upstream triggering factor, could be a promising diagnostic and therapeutic target for NA.

New targets for type 2-low asthma

Asthma is characterized by airway obstruction and inflammation, and presents significant diagnostic and treatment challenges. The concept of endotypes has improved understanding of the mechanisms of asthma and has stimulated the development of effective treatment strategies. Sputum profiles may be used to classify asthma into two major inflammatory types: type 2-high (T2H) and type 2-low (T2L) asthma. T2H, characterized by elevated type 2 inflammation, has been extensively studied and several effective biologic treatments have been developed. However, managing T2L is more difficult due to the lack of reliable biomarkers for accurate diagnosis and classification. Additionally, conventional anti-inflammatory therapy does not completely control the symptoms of T2L; therefore, further research is needed to identify effective biologic treatments. This review provides new insights into the clinical characteristics and underlying mechanisms of severe T2L and investigates potential therapeutic approaches to control the disease.

Inflammation as the nexus: exploring the link between acute myocardial infarction and chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), particularly following acute exacerbations (AE-COPD), significantly heightens the risks and mortality associated with acute myocardial infarction (AMI). The intersection of COPD and AMI is characterised by a considerable overlap in inflammatory mechanisms, which play a crucial role in the development of both conditions. Although extensive research has been conducted on individual inflammatory pathways in AMI and COPD, the understanding of thrombo-inflammatory crosstalk in comorbid settings remains limited. The effectiveness of various inflammatory components in reducing AMI infarct size or slowing COPD progression has shown promise, yet their efficacy in the context of comorbidity with COPD and AMI is not established. This review focuses on the critical importance of both local and systemic inflammation, highlighting it as a key pathophysiological connection between AMI and COPD/AE-COPD.

Respiratory Health Effects of Air Pollutants

Air pollution is a risk factor for asthma and respiratory infection. Avoidance of air pollution is the best approach to mitigating the impacts of pollution. Personal preventive strategies are possible, but policy interventions are the most effective ways to prevent pollution and its effect on asthma and respiratory infection.

Transcriptomic characterization of the human segmental endotoxin challenge model

Segmental instillation of lipopolysaccharide (LPS) by bronchoscopy safely induces transient airway inflammation in human lungs. This model enables investigation of pulmonary inflammatory mechanisms as well as pharmacodynamic analysis of investigational drugs. The aim of this work was to describe the transcriptomic profile of human segmental LPS challenge with contextualization to major respiratory diseases. Pre-challenge bronchoalveolar lavage (BAL) fluid and biopsies were sampled from 28 smoking, healthy participants, followed by segmental instillation of LPS and saline as control. Twenty-four hours post instillation, BAL and biopsies were collected from challenged lung segments. Total RNA of cells from BAL and biopsy samples were sequenced and analysed for differentially expressed genes (DEGs). After challenge with LPS compared with saline, 6316 DEGs were upregulated and 241 were downregulated in BAL, but only one DEG was downregulated in biopsy samples. Upregulated DEGs in BAL were related to molecular functions such as "Inflammatory response" or "chemokine receptor activity", and upregulated pro-inflammatory pathways such as "Wnt-"/"Ras-"/"JAK-STAT" "-signaling pathway". Furthermore, the segmental LPS challenge model resembled aspects of the five most prevalent respiratory diseases chronic obstructive pulmonary disease (COPD), asthma, pneumonia, tuberculosis and lung cancer and featured similarities with acute exacerbations in COPD (AECOPD) and community-acquired pneumonia. Overall, our study provides extensive information about the transcriptomic profile from BAL cells and mucosal biopsies following LPS challenge in healthy smokers. It expands the knowledge about the LPS challenge model providing potential overlap with respiratory diseases in general and infection-triggered respiratory insults such as AECOPD in particular.

The effect of bradykinin 1 receptor antagonist BI 1026706 on pulmonary inflammation after segmental lipopolysaccharide challenge in healthy smokers

BACKGROUND

Bradykinin 1 receptor (B1R) signalling pathways may be involved in the inflammatory pathophysiology of chronic obstructive pulmonary disease (COPD). B1R signalling is induced by inflammatory stimuli or tissue injury and leads to activation and increased migration of pro-inflammatory cells. Lipopolysaccharide (LPS) lung challenge in man is an experimental method of exploring inflammation in the lung whereby interference in these pathways can help to assess pharmacologic interventions in COPD. BI 1026706, a potent B1R antagonist, was hypothesized to reduce the inflammatory activity after segmental lipopolysaccharide (LPS) challenge in humans due to decreased pulmonary cell influx.

METHODS

In a monocentric, randomized, double-blind, placebo-controlled, parallel-group, phase I trial, 57 healthy, smoking subjects were treated for 28 days with either oral BI 1026706 100 mg bid or placebo. At day 21, turbo-inversion recovery magnitude magnetic resonance imaging (TIRM MRI) was performed. On the last day of treatment, pre-challenge bronchoalveolar lavage fluid (BAL) and biopsies were sampled, followed by segmental LPS challenge (40 endotoxin units/kg body weight) and saline control instillation in different lung lobes. Twenty-four hours later, TIRM MRI was performed, then BAL and biopsies were collected from the challenged segments. In BAL samples, cells were differentiated for neutrophil numbers as the primary endpoint. Other endpoints included assessment of safety, biomarkers in BAL (e.g. interleukin-8 [IL-8], albumin and total protein), B1R expression in lung biopsies and TIRM score by MRI as a measure for the extent of pulmonary oedema.

RESULTS

After LPS, but not after saline, high numbers of inflammatory cells, predominantly neutrophils were observed in the airways. IL-8, albumin and total protein were also increased in BAL samples after LPS challenge as compared with saline control. There were no significant differences in cells or other biomarkers from BAL in volunteers treated with BI 1026706 compared with those treated with placebo. Unexpectedly, neutrophil numbers in BAL were 30% higher and MRI-derived extent of oedema was significantly higher with BI 1026706 treatment compared with placebo, 24 h after LPS challenge. Adverse events were mainly mild to moderate and not different between treatment groups.

CONCLUSIONS

Treatment with BI 1026706 for four weeks was safe and well-tolerated in healthy smoking subjects. BI 1026706 100 mg bid did not provide evidence for anti-inflammatory effects in the human bronchial LPS challenge model.

TRIAL REGISTRATION

The study was registered on January 14, 2016 at ClinicalTrials.gov (NCT02657408).

IL-1 receptor antagonist attenuates proinflammatory responses to rhinovirus in airway epithelium

BACKGROUND

Rhinoviruses (RVs) are the most common trigger for asthma exacerbations, and there are currently no targeted therapies for viral-induced asthma exacerbations. RV infection causes neutrophilic inflammation, which is often resistant to effects of glucocorticoids. IL-1 receptor antagonist (IL-1RA) treatment reduces neutrophilic inflammation in humans challenged with inhaled endotoxin and thus may have therapeutic potential for RV-induced asthma exacerbations.

OBJECTIVE

We sought to test the hypothesis that IL-1RA treatment of airway epithelium reduces RV-mediated proinflammatory cytokine production, which is important for neutrophil recruitment.

METHODS

Human bronchial epithelial cells from deceased donors without prior pulmonary disease were cultured at air-liquid interface and treated with IL-13 to approximate an asthmatic inflammatory milieu. Human bronchial epithelial cells were infected with human RV-16 with or without IL-1RA treatment.

RESULTS

RV infection promoted the release of IL-1α and the neutrophil-attractant cytokines IL-6, IL-8, and CXCL10. Proinflammatory cytokine secretion was significantly reduced by IL-1RA treatment without significant change in IFN-β release or RV titer. In addition, IL-1RA reduced MUC5B expression after RV infection without impacting MUC5AC.

CONCLUSIONS

These data suggest that IL-1RA treatment significantly reduced proinflammatory cytokines while preserving the antiviral response. These results provide evidence for further investigation of IL-1RA as a novel targeted therapy against neutrophil-attractant cytokine release in RV-induced airway inflammatory responses.

Evaluation of genetic variants in ferroptosis-related genes and house dust mite-induced allergic rhinitis risk

BACKGROUND

Ferroptosis-related genes disrupt iron homeostasis and enhance lipid peroxidation to initiate respiratory system diseases. However, the association between genetic variants in the ferroptosis-related genes with house dust mite (HDM)-induced allergic rhinitis (AR) susceptibility remains unclear.

METHODS

A case-control study, involving 222 cases and 237 healthy controls from a Chinese population, was conducted to evaluate the relationship between single nucleotide polymorphisms (SNPs) in ferroptosis-related genes and HDM-induced AR risk. A gene-based analysis was performed by multi-marker analysis of genomic annotation (MAGMA) to identify candidate associated ferroptosis-related genes. A logistic regression model and joint analysis were used to assess the effect of SNPs on HDM-induced AR susceptibility.

RESULTS

Two independent SNPs (rs2305128 in ENPP2 and rs1868088 in EPAS1) were significantly associated with HDM-induced AR risk (OR = 1.82, 95% CI = 1.19-2.79, P = 5.98 × 10-3, PFDR = 4.88 × 10-2; OR = 2.14, 95% CI = 1.23-3.72, P = 6.95 × 10-3, PFDR = 4.87 × 10-2, respectively). Moreover, combined analysis of these two SNPs revealed that an increased risk of HDM-induced AR was positively associated with an increasing number of risk genotypes (Ptrend = 8.48 × 10-5). The stratification analysis showed that the cumulative effect of two SNPs on HDM-induced AR risk was more pronounced among patients presenting more serious symptoms and harboring one or two risk genotypes.

CONCLUSIONS

These findings suggest that the genetic variants in ferroptosis-related genes ENPP2 and EPAS1 may increase HDM-induced AR risk and serve as potential predictors of HDM-induced AR susceptibility.

How an Immune-Factor-Based Formulation of Micro-Immunotherapy Could Interfere with the Physiological Processes Involved in the Atopic March

Allergic diseases consist of improper inflammatory reactions to antigens and are currently an important healthcare concern, especially considering their increasing worldwide development in recent decades. The "atopic march" defines the paradigm of allergic diseases occurring in chronological order and displaying specific spatial manifestations, as they usually start as atopic dermatitis (AD) and food allergies during infancy and progressively evolve into allergic asthma (AA) and allergic rhinitis (AR) or rhino-conjunctivitis in childhood. Many immune cell subtypes and inflammatory factors are involved in these hypersensitivity reactions. In particular, the T helpers 2 (Th2) subset, through its cytokine signatures made of interleukins (ILs), such as IL-4, IL-5, IL-10, and IL-13, as well as mast cells and their related histamine pathways, contribute greatly to the perpetuation and evolution of the atopic march. By providing low doses (LD) and ultra-low doses (ULD) of ILs and immune factors to the body, micro-immunotherapy (MI) constitutes an interesting therapeutic strategy for the management of the atopic march and its symptoms. One of the aims of this review is to shed light on the current concept of the atopic march and the underlying immune reactions occurring during the IgE-mediated responses. Moreover, the different classes of traditional and innovative treatments employed in allergic diseases will also be discussed, with a special emphasis on the potential benefits of the MI medicine 2LALERG^® formulation in this context.

Neutrophil phenotypes in bronchial airways differentiate single from dual responding allergic asthmatics

INTRODUCTION

Allergic asthmatics with both an early (EAR) and a late allergic reaction (LAR) following allergen exposure are termed 'dual responders' (DR), while 'single responders' (SR) only have an EAR. Mechanisms that differentiate DR from SR are largely unknown, particularly regarding the role and phenotypes of neutrophils. Therefore, we aimed to study neutrophils in DR and SR asthmatics.

METHODS

Thirty-four allergic asthmatics underwent an inhaled allergen challenge, samples were collected before and up to 24 h post-challenge. Cell differentials were counted from bronchial lavage, alveolar lavage and blood; and tissue neutrophils were quantified in immune-stained bronchial biopsies. Lavage neutrophil nuclei lobe segmentation was used to classify active (1-4 lobes) from suppressive neutrophils (≥5 lobes). Levels of transmigration markers: soluble (s)CD62L and interleukin-1Ra, and activity markers: neutrophil elastase (NE), DNA-histone complex and dsDNA were measured in lavage fluid and plasma.

RESULTS

Compared with SR at baseline, DR had more neutrophils in their bronchial airways at baseline, both in the lavage (p = .0031) and biopsies (p = .026) and elevated bronchial neutrophils correlated with less antitransmigratory IL-1Ra levels (r = -0.64). DR airways had less suppressive neutrophils and more 3-lobed (active) neutrophils (p = .029) that correlated with more bronchial lavage histone (p = .020) and more plasma NE (p = .0016). Post-challenge, DR released neutrophil extracellular trap factors in the blood earlier and had less pro-transmigratory sCD62L during the late phase (p = .0076) than in SR.

CONCLUSION

DR have a more active airway neutrophil phenotype at baseline and a distinct neutrophil response to allergen challenge that may contribute to the development of an LAR. Therefore, neutrophil activity should be considered during targeted diagnosis and bio-therapeutic development for DR.

Classifications of moderate to severe asthma phenotypes in Japan and analysis of serum biomarkers: A Nationwide Cohort Study in Japan (NHOM Asthma Study)

BACKGROUND

Asthma is a heterogeneous disease, and phenotyping can facilitate understanding of disease pathogenesis and direct appropriate asthma treatment. This nationwide cohort study aimed to phenotype asthma patients in Japan and identify potential biomarkers to classify the phenotypes.

METHODS

Adult asthma patients (n = 1925) from 27 national hospitals in Japan were enrolled and divided into Global Initiative for Asthma (GINA) steps 4 or 5 (GINA 4, 5) and GINA Steps 1, 2, or 3 (GINA 1-3) for therapy. Clinical data and questionnaires were collected. Biomarker levels among GINA 4, 5 patients were measured. Ward's minimum variance hierarchical clustering method and tree analysis were performed for phenotyping. Analysis of variance, the Kruskal-Wallis, and chi-square tests were used to compare cluster differences.

RESULTS

The following five clusters were identified: 1) late-onset, old, less-atopic; 2) late-onset, old, eosinophilic, low FEV₁; 3) early-onset, long-duration, atopic, poorly controlled; 4) early-onset, young, female-dominant, atopic; and 5) female-dominant, T1/T2-mixed, most severe. Age of onset, disease duration, blood eosinophils and neutrophils, asthma control questionnaire Sum 6, number of controllers, FEV₁, body mass index (BMI), and hypertension were the phenotype-classifying variables determined by tree analysis that assigned 79.5% to the appropriate cluster. Among the cytokines measured, IL-1RA, YKL40/CHI3L1, IP-10/CXCL10, RANTES/CCL5, and TIMP-1 were useful biomarkers for classifying GINA 4, 5 phenotypes.

CONCLUSIONS

Five distinct phenotypes were identified for moderate to severe asthma and may be classified using clinical and molecular variables (Registered in UMIN-CTR; UMIN000027776.).

IL-1β and Allergy: Focusing on Its Role in Allergic Rhinitis

Allergic rhinitis (AR) is a chronic upper airway immune-inflammation response mediated by immunoglobulin E (IgE) to allergens and can seriously affect the quality of life and work efficiency. Previous studies have shown that interleukin-1β (IL-1β) acts as a key cytokine to participate in and promote the occurrence and development of allergic diseases. It has been proposed that IL-1β may be a potential biomarker of AR. However, its definitive role and potential mechanism in AR have not been fully elucidated, and the clinical sample collection and detection methods were inconsistent among different studies, which have limited the use of IL-1β as a clinical diagnosis and treatment marker for AR. This article systematically summarizes the research advances in the roles of IL-1β in allergic diseases, focusing on the changes of IL-1β in AR and the possible interventions. In addition, based on the findings by our team, we provided new insights into the use of IL-1β in AR diagnosis and treatment, in an attempt to further promote the clinical application of IL-1β in AR and other allergic diseases.

NOD-like receptors in asthma

Asthma is an extremely prevalent chronic inflammatory disease of the airway where innate and adaptive immune systems participate collectively with epithelial and other structural cells to cause airway hyperresponsiveness, mucus overproduction, airway narrowing, and remodeling. The nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) are a family of intracellular innate immune sensors that detect microbe-associated molecular patterns and damage-associated molecular patterns, well-recognized for their central roles in the maintenance of tissue homeostasis and host defense against bacteria, viruses and fungi. In recent times, NLRs have been increasingly acknowledged as much more than innate sensors and have emerged also as relevant players in diseases classically defined by their adaptive immune responses such as asthma. In this review article, we discuss the current knowledge and recent developments about NLR expression, activation and function in relation to asthma and examine the potential interventions in NLR signaling as asthma immunomodulatory therapies.

LPS differentially affects expression of CD14 and CCR2 in monocyte subsets of Post-STEMI patients with hyperglycemia

AIMS

Following ST-segment elevation myocardial infarction (STEMI), recruitment and activation of monocytes [classical (CD14⁺⁺CD16^-CCR2⁺⁺), intermediate (CD14⁺⁺CD16⁺CCR2⁺), non-classical (CD14^LowCD16⁺⁺CCR2^Low)] are needed for myocardial wound healing. Monocyte surface receptor CC chemokine receptor type 2 (CCR2) is responsible for monocyte chemotaxis to sites of inflammation and the lipopolysaccharide (LPS)-binding protein co-receptor, CD14, is involved in pro-inflammatory monocyte activation. The purpose of this investigation was to determine the effects of ex-vivo LPS activation on monocyte subset CD14 and CCR2 expression in post-STEMI individuals with normal and elevated random blood glucose.

METHODS

Post-STEMI subjects were identified as normal random glucose (NG, <98 mg/dL, n = 13) or impaired random glucose (IG, ≥98 mg/dL, n = 26) and monocytes were analyzed for non-activated and LPS-activated (1 µg/mL for 4 h) CCR2 and CD14 expression.

RESULTS

Non-activated intermediate monocytes from IG showed decreased CD14 expression when compared to NG, which was maintained following LPS-activation. The NG group showed a larger absolute reduction in classical CCR2 expression, leading to a significant difference between NG and IG following LPS-activation.

CONCLUSION

Results suggest a heightened response to pro-inflammatory activation in IG following STEMI, which may impair or delay post-STEMI myocardial healing, and thus increase the incidence of chronic heart failure. NIH 1R34HL121402.

Clinical implications of asthma endotypes and phenotypes

Background: Asthma is a complex disorder with variable clinical expression. Recognizable clinical and laboratory features define phenotypes, and specific biologic pathways define endotypes. Identifying the specific pathway responsible for persistent asthma would enable the clinician to select the optimal inhibitors, which currently are biologic therapies. Objective: To provide an up-to-date review of the current clinical status of endotype and phenotype characterizations of asthma and discuss these categories in relation to the available, or likely available, biologic therapies for asthma. Methods: The medical literature was reviewed based on the search terms: asthma biologics, severe asthma, uncontrolled asthma, corticosteroid-dependent asthma, phenotype, endotype, and type 2. We also used our knowledge of the literature and current research. Results: All of the current biologics, including the recently approved tezepelumab, were most effective with increased type 2 biomarkers, which identify exacerbation-prone asthma. Current biomarkers do not permit consistent identification of specific endotypes to facilitate informed selection of the optimal therapy for an individual patient. Thus, empiricism and the art of care continue to play major roles in treatment selection. Conclusion: Current biologic therapies for asthma and those likely to be U.S. Food and Drug Administration approved within the near future work best in subjects with strong type 2 signatures. Available biomarkers and observable characteristics do not enable clinicians to recognize specific endotypes, but rather subphenotypes or overlapping endotypes. The goal of identifying the optimal patient for a specific therapy remains elusive, but worthy of pursuit. In the interim, the availability of an increasing number of treatment options allows the clinician to help most of his or her patients.

Integration of healthy volunteers in early phase clinical trials with immuno-oncological compounds

Aim

Traditionally, early phase clinical trials in oncology have been performed in patients based on safety risk-benefit assessment. Therapeutic transition to immuno-oncology may open new opportunities for studies in healthy volunteers, which are conducted faster and are less susceptible to confounders. Aim of this study was to investigate to what extent this approach is utilized and whether pharmacodynamic endpoints are evaluated in these early phase trials. We conducted a comprehensive review of clinical trials with healthy volunteers using immunotherapies potentially relevant for oncology.

Methods

Literature searches according to PRISMA guidelines and after registration in PROSPERO were conducted in PubMed, Embase, Web of Science and Cochrane databases with the cut-off date 20 October 2020, using search terms of relevant targets in immuno-oncology. Articles describing clinical trials with immunotherapeutics in healthy volunteers with a mechanism relevant for oncology were included. “Immunotherapeutic” was defined as compounds exhibiting effects through immunological targets. Data including study design and endpoints were extracted, with specific attention to pharmacodynamic endpoints and safety.

Results

In total, we found 38 relevant immunotherapeutic compounds tested in HVs, with 86% of studies investigating safety, 82% investigating the pharmacokinetics (PK) and 57% including at least one pharmacodynamic (PD) endpoint. Most of the observed adverse events (AEs) were Grade 1 and 2, consisting mostly of gastrointestinal, cutaneous and flu-like symptoms. Severe AEs were leukopenia, asthenia, syncope, headache, flu-like reaction and liver enzymes increase. PD endpoints investigated comprised of cytokines, immune and inflammatory biomarkers, cell counts, phenotyping circulating immune cells and ex vivo challenge assays.

Discussion

Healthy volunteer studies with immuno-oncology compounds have been performed, although not to a large extent. The integration of healthy volunteers in well-designed proof-of-mechanism oriented drug development programs has advantages and could be pursued more in the future, since integrative clinical trial protocols may facilitate early dose selection and prevent cancer patients to be exposed to non-therapeutic dosing regimens.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=210861, identifier CRD42020210861

The Interactions Between Autoinflammation and Type 2 Immunity: From Mechanistic Studies to Epidemiologic Associations

Autoinflammatory diseases are a group of clinical syndromes characterized by constitutive overactivation of innate immune pathways. This results in increased production of or responses to monocyte- and neutrophil-derived cytokines such as interleukin-1β (IL-1β), Tumor Necrosis Factor-α (TNF-α), and Type 1 interferon (IFN). By contrast, clinical allergy is caused by dysregulated type 2 immunity, which is characterized by expansion of T helper 2 (Th2) cells and eosinophils, as well as overproduction of the associated cytokines IL-4, IL-5, IL-9, and IL-13. Traditionally, type 2 immune cells and autoinflammatory effectors were thought to counter-regulate each other. However, an expanding body of evidence suggests that, in some contexts, autoinflammatory pathways and cytokines may potentiate type 2 immune responses. Conversely, type 2 immune cells and cytokines can regulate autoinflammatory responses in complex and context-dependent manners. Here, we introduce the concepts of autoinflammation and type 2 immunity. We proceed to review the mechanisms by which autoinflammatory and type 2 immune responses can modulate each other. Finally, we discuss the epidemiology of type 2 immunity and clinical allergy in several monogenic and complex autoinflammatory diseases. In the future, these interactions between type 2 immunity and autoinflammation may help to expand the spectrum of autoinflammation and to guide the management of patients with various autoinflammatory and allergic diseases.

T2-low: what do we know?: Past, present, and future of biologic therapies in noneosinophilic asthma

T2-low asthma is an often severe asthma subtype with limited treatment options and biologic therapeutics are lacking. Several monoclonal antibodies (mAbs) targeting non-T2 cytokines were previously reported to be ineffective in asthma. These trials often investigated heterogeneous asthma populations and negative outcomes could be related to unsuitable study cohorts. More tailored approaches in selecting participants based on specific biomarkers have been beneficial in treating severe T2-high asthma. Similarly, mAbs previously deemed ineffective bear the potential to be useful when administered to the correct target population. Here, we review individual clinical trials conducted between 2005 and 2021 and assess the suitability of the selected cohorts, whether study end points were met, and whether outcome measures were appropriate to investigate the effectiveness of the respective drug. We discuss potential target groups within the T2-low asthma population and suggest biomarkers that may predict a treatment response. Furthermore, we assess whether biomarker-guided approaches or subgroup analyses were associated with more positive study outcomes. The mAbs directed against alarmins intervene early in the inflammatory cascade and are the first mAbs found to have efficacy in T2-low asthma. Several randomized controlled trials performed predefined subgroup analyses that included T2-low asthma. Subgroup analyses were associated with positive outcomes and were able to reveal a stronger response in at least 1 subgroup. A better understanding of T2-low subgroups and specific biomarkers is necessary to identify the most responsive target population for a given mAb.

Innate Lymphoid Cells Are Required to Induce Airway Hyperreactivity in a Murine Neutrophilic Asthma Model

Rationale

Non-allergic asthma is driven by multiple endotypes of which neutrophilic and pauci-granulocytic asthma have been best established. However, it is still puzzling what drives inflammation and airway hyperreactivity (AHR) in these patients and how it can be treated effectively. Recently, a potential role of the innate immune system and especially the innate lymphoid cells (ILC) has been proposed.

Objective

In this study, we investigated the effects of LPS inhalation on airway inflammation and AHR as a potential model for elucidating the pathogenesis of non-allergic asthma.

Methods

Wild-type (BALB/c), SCID, IL-17A^-/-, and Rag2^-/- γC^-/- mice were endonasally exposed to lipopolysaccharide (LPS, 2 µg) on four consecutive days. Twenty-four hours after the last exposure, AHR to methacholine was assessed. Cytokine levels and ILC subpopulations were determined in lung tissue. Cellular differential analysis was performed in BAL fluid.

Main Results

In this study, we developed a murine model for non-allergic neutrophilic asthma. We found that repeated endonasal applications of low-dose LPS in BALB/c mice led to AHR, BAL neutrophilia, and a significant increase in lung ILC3 as well as a significant increase in lung chemokines KC and MIP-2 and cytokines IL-1β, IL-17A, IL-22, and TNF. The adoptive transfer of ILC in Rag2^-/- γC^-/- mice showed that ILC played a causal role in the induction of AHR in this model. Antagonising IL-1β, but not IL-17A or neutrophils, resulted in a partial reduction in LPS-induced AHR.

Conclusion

In conclusion, we report here a murine model for neutrophilic asthma where ILC are required to induce airway hyperreactivity.

TH17 cells and corticosteroid insensitivity in severe asthma

Asthma is classically described as having either a type 2 (T2) eosinophilic phenotype or a non-T2 neutrophilic phenotype. T2 asthma usually responds to classical bronchodilation therapy and corticosteroid treatment. Non-T2 neutrophilic asthma is often more severe. Patients with non-T2 asthma or late-onset T2 asthma show poor response to the currently available anti-inflammatory therapies. These therapeutic failures result in increased morbidity and cost associated with asthma and pose a major health care problem. Recent evidence suggests that some non-T2 asthma is associated with elevated T_H17 cell immune responses. T_H17 cells producing Il-17A and IL-17F are involved in the neutrophilic inflammation and airway remodeling processes in severe asthma and have been suggested to contribute to the development of subsets of corticosteroid-insensitive asthma. This review explores the pathologic role of T_H17 cells in corticosteroid insensitivity of severe asthma and potential targets to treat this endotype of asthma.

The onset, development and pathogenesis of severe neutrophilic asthma

Bronchial asthma is divided into Th2 high, Th2 low and mixed types. The Th2 high type is dominated by eosinophils while the Th2 low type is divided into neutrophilic and paucigranulocytic types. Eosinophilic asthma has gained increased attention recently, and its pathogenesis and treatment are well understood. However, severe neutrophilic asthma requires more in-depth research because its pathogenesis is not well understood, and no effective treatment exists. This review looks at the advances made in asthma research, the pathogenesis of neutrophilic asthma, the mechanisms of progression to severe asthma, risk factors for asthma exacerbations, and biomarkers and treatment of neutrophilic asthma. The pathogenesis of neutrophilic asthma is further discussed from four aspects: Th17-type inflammatory response, inflammasomes, exosomes and microRNAs. This review provides direction for the mechanistic study, diagnosis and treatment of neutrophilic asthma. The treatment of neutrophilic asthma remains a significant challenge for clinical therapists and is an important area of future clinical research.

Biological Treatments and Target Therapies for Pediatric Respiratory Medicine: Not Only Asthma

We present a description of pediatric pneumology biological medications and other target therapies. The article aims at introducing the importance of a molecular approach to improve treatments. The first item treated was T2-High asthma and its current biological treatment and prescribing indications to propose a flow-chart to guide the clinical choice. Molecular rationales of such treatments are used to introduce a more general description of the biological and molecular approach to target therapies application. We introduce a general interpretation approach to neutrophilic asthma using the molecular plausibility one in order to propose possible future treatments mainly targeting interleukin-1 (IL-1), IL-17, IL-12, and IL-23. Indeed, cytokines can be excellent targets for several biological treatments. Downregulation of specific cytokines can be crucial in treating autoinflammatory and rheumatological diseases with a pulmonary involvement. Such conditions, although rare, should be early recognized as they can involve significant improvement with a properly targeted therapy. We face these conditions in a cherry-picking fashion picturing SAVI (STING-associated vasculopathy with onset in infancy), CANDLE (chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature), and COPA (coat proteins alpha syndrome) syndrome pulmonary involvement. Such examples are functional to introduce molecular-based approach for patients with rare conditions. Molecular plausibility can be highly valuable in treating patients with not-approved but possibly highly effective therapies. Due to the rarity of these conditions, we stress the concept of basket trials using the example of cytokinin-directed immunosuppressive treatment. Lastly, we provide an example of augmentative therapy using the alpha1 antitrypsin deficiency as a model. In summary, the article presents a collection of the most recent achievements and some possible future developments of target therapies for pediatric pulmonary conditions.

Airway IL-1β associates with IL-5 production following dust mite allergen inhalation in humans

BACKGROUND

Preclinical studies implicate interleukin (IL)-1β as a key mediator of asthma and have shown the efficacy of IL-1 antagonism for treatment of allergic airway inflammation; human studies in this area are lacking.

OBJECTIVES

Our aim was to study the relationship of airway IL-1β to features of acute allergen-induced asthma exacerbation in humans.

METHODS

Dust mite-allergic adults with mild asthma underwent inhalation challenge with Dermatophagoides farinae. Fractional exhaled nitric oxide (FeNO), induced sputum and peripheral blood samples were obtained pre- and 24 h post-challenge. Spirometry was performed before and throughout the challenge at 10-min intervals, and allergen responsiveness was defined by a 20% fall in Forced Expiratory Volume in 1 s (FEV₁). Sputum samples were analyzed for inflammatory cells, cytokines and chemokines. Multiple linear regression was employed to test the association between sputum IL-1β concentration and biomarkers of T helper type 2 (T2)-dominant inflammation.

RESULTS

Fourteen volunteers underwent inhaled allergen challenge. Allergen responsive volunteers showed a greater positive change in IL-1β in sputum following allergen challenge compared to non-responders. Higher pre-challenge sputum IL-1β was associated with greater increase in sputum IL-5 (p = 0.004), sputum eosinophils (p = 0.001) and blood IL-5 (p = 0.003) following allergen challenge. Allergen-induced sputum IL-1β production was significantly associated with sputum and blood IL-5 (p < 0.001 and p = 0.007, respectively), sputum IL-4 (p = 0.001), IL-13 (p = 0.026), eosinophils (p = 0.008) and FeNO (p = 0.03).

CONCLUSIONS

The positive association between production of IL-1β and biomarkers of T2 inflammation, particularly IL-5, in humans is consistent with work in animal models that demonstrates a link between IL-1β and the pathophysiology of allergic asthma. The role of IL-1β in human asthma warrants further study.

Practical Review of Biologics in Chronic Rhinosinusitis With Nasal Polyps

Well-characterized in chronic rhinosinusitis, type 2 inflammation is frequently associated with nasal polyps, comorbid asthma, and nonsteroidal anti-inflammatory drug hypersensitivity. Despite medical and surgical treatment, it recurs in a significant proportion of patients. Thus, severe uncontrolled type 2 chronic rhinosinusitis with nasal polyps is the most difficult-to-treat phenotype of chronic rhinosinusitis. Recently, dupilumab, a monoclonal antibody against IL-4 receptor α, and omalizumab, a monoclonal antibody against immunoglobulin E, were approved for patients with chronic rhinosinusitis with nasal polyps in the United States, Europe, and Korea. Therefore, rhinologists should understand novel biologics and their use. Here, we provide a literature review of several biologics with their indications, effectiveness, and safety.

Interrupting the Conversation: Implications for Crosstalk Between Viral and Bacterial Infections in the Asthmatic Airway

Asthma is a heterogeneous, chronic respiratory disease affecting 300 million people and is thought to be driven by different inflammatory endotypes influenced by a myriad of genetic and environmental factors. The complexity of asthma has rendered it challenging to develop preventative and disease modifying therapies and it remains an unmet clinical need. Whilst many factors have been implicated in asthma pathogenesis and exacerbations, evidence indicates a prominent role for respiratory viruses. However, advances in culture-independent detection methods and extensive microbial profiling of the lung, have also demonstrated a role for respiratory bacteria in asthma. In particular, airway colonization by the Proteobacteria species Nontypeable Haemophilus influenzae (NTHi) and Moraxella catarrhalis (Mcat) is associated with increased risk of developing recurrent wheeze and asthma in early life, poor clinical outcomes in established adult asthma and the development of more severe inflammatory phenotypes. Furthermore, emerging evidence indicates that bacterial-viral interactions may influence exacerbation risk and disease severity, highlighting the need to consider the impact chronic airway colonization by respiratory bacteria has on influencing host responses to viral infection. In this review, we first outline the currently understood role of viral and bacterial infections in precipitating asthma exacerbations and discuss the underappreciated potential impact of bacteria-virus crosstalk in modulating host responses. We discuss the mechanisms by which early life infection may predispose to asthma development. Finally, we consider how infection and persistent airway colonization may drive different asthma phenotypes, with a view to identifying pathophysiological mechanisms that may prove tractable to new treatment modalities.

Local Defence System in Healthy Lungs

Background: The respiratory system is one of the main entrance gates for infection. The aim of this work was to compare the appearance of specific mucosal pro-inflammatory and common anti-microbial defence factors in healthy lung tissue, from an ontogenetic point of view. Materials and methods: Healthy lung tissues were collected from 15 patients (three females and 12 males) in the age range from 18 to 86. Immunohistochemistry to human β defensin 2 (HBD-2), human β defensin 3 (HBD-3), human β defensin 4 (HBD-4), cathelicidine (LL-37) and interleukine 17A (IL-17A) were performed. Results: The lung tissue material contained bronchial and lung parenchyma material in which no histological changes, connected with the inflammatory process, were detected. During the study, various statistically significant differences were detected in immunoreactive expression between different factors in all lung tissue structures. Conclusion: All healthy lung structures, but especially the cartilage, alveolar epithelium and the alveolar macrophages, are the main locations for the baseline synthesis of antimicrobial proteins and IL-17A. Cartilage shows high functional plasticity of this structure, including significant antimicrobial activity and participation in local lung protection response. Interrelated changes between antimicrobial proteins in different tissue confirm baseline synergistical cooperation of all these factors in healthy lung host defence.

New Insights into the Role of NLRP3 Inflammasome in Pathogenesis and Treatment of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is an inflammatory lung disease characterized by chronic airway obstruction and emphysema. Accumulating studies have shown that the onset and development of COPD are related to an aberrant immune response induced by the dysregulation of a number of genetic and environmental factors, while the exact pathogenesis of this disease is not well defined. Emerging studies based on tests on samples from COPD patients, animal models, pharmacological and genetic data suggest that the NLR family pyrin domain containing 3 (NLRP3) inflammasome activation is required in the lung inflammatory responses in the development of COPD. Although the available clinical studies targeting the inflammasome effector cytokine, IL-1β, or IL-1 signaling do not show positive outcomes for COPD treatment, many alternative strategies have been proposed by recent emerging studies. Here, we highlight the recent progress in our understanding of the role of the NLRP3 inflammasome in COPD and propose possible future studies that may further elucidate the roles of the inflammasome in the pathogenesis or the intervention of this inflammatory lung disease.

Severe asthma: what is new in the new millennium

PURPOSE OF REVIEW

Severe asthma remains a debilitating disease and a challenge for the clinicians. Novel therapies have been introduced and have greatly improved asthma control and more are under development or in clinical studies. These include anti-IL5/IL5R, anti-IL4/IL4R, anti IL13, anti- thymic stromal lymphopoietin (TSLP) and more, and severe asthma is currently managed in personalized medicine approach. However, there is still an unmet need to discover new, clinically available biomarkers and targeted therapies for a large group of severe asthma patients, particularly those with T2-low asthma. In this review, we briefly present the phenotypes and endotypes of severe asthma, the omics technologies in asthma as well as current and future treatments for both T2-high and T2-low asthma.

RECENT FINDINGS

In this review, we are going to present the effectiveness and safety of anti-IL5 therapies, the clinical trials for dupilumab and tezepelumab and the most significant molecules and biological agents used in trials as possible treatments forT2-low asthma.

SUMMARY

Novel anti-IL5 agents have changed the management of T2-high asthma resulting in improved disease control, QoL and lung function and importantly, fewer exacerbations. Nevertheless, there is still the need to find new treatments, particularly for T2-low asthma, which remains a challenge.

Identification and treatment of T2-low asthma in the era of biologics

Currently, and based on the development of relevant biologic therapies, T2-high is the most well-defined endotype of asthma. Although much progress has been made in elucidating T2-high inflammation pathways, no specific clinically applicable biomarkers for T2-low asthma have been identified. The therapeutic approach of T2-low asthma is a problem urgently needing resolution, firstly because these patients have poor response to steroids, and secondly because they are not candidates for the newer targeted biologic agents. Thus, there is an unmet need for the identification of biomarkers that can help the diagnosis and endotyping of T2-low asthma. Ongoing investigation is focusing on neutrophilic airway inflammation mediators as therapeutic targets, including interleukin (IL)-8, IL-17, IL-1, IL-6, IL-23 and tumour necrosis factor-α; molecules that target restoration of corticosteroid sensitivity, mainly mitogen-activated protein kinase inhibitors, tyrosine kinase inhibitors and phosphatidylinositol 3-kinase inhibitors; phosphodiesterase (PDE)3 inhibitors that act as bronchodilators and PDE4 inhibitors that have an anti-inflammatory effect; and airway smooth muscle mass attenuation therapies, mainly for patients with paucigranulocytic inflammation. This article aims to review the evidence for noneosinophilic inflammation being a target for therapy in asthma; discuss current and potential future therapeutic approaches, such as novel molecules and biologic agents; and assess clinical trials of licensed drugs in the treatment of T2-low asthma.

Modern View of Neutrophilic Asthma Molecular Mechanisms and Therapy

For a long time asthma was commonly considered as a homogeneous disease. However, recent studies provide increasing evidence of its heterogeneity and existence of different phenotypes of the disease. Currently, classification of asthma into several phenotypes is based on clinical and physiological features, anamnesis, and response to therapy. This review describes five most frequently identified asthma phenotypes. Neutrophilic asthma (NA) deserves special attention, since neutrophilic inflammation of the lungs is closely associated with severity of the disease and with the resistance to conventional corticosteroid therapy. This review focuses on molecular mechanisms of neutrophilic asthma pathogenesis and on the role of Th1- and Th17-cells in the development of this type of asthma. In addition, this review presents current knowledge of neutrophil biology. It has been established that human neutrophils are represented by at least three subpopulations with different biological functions. Therefore, total elimination of neutrophils from the lungs can result in negative consequences. Based on the new knowledge of NA pathogenesis and biology of neutrophils, the review summarizes current approaches for treatment of neutrophilic asthma and suggests new promising ways to treat this type of asthma that could be developed in future.

Treatment options in type-2 low asthma

Monoclonal antibodies targeting IgE or the type-2 cytokines interleukin (IL)-4, IL-5 and IL-13 are proving highly effective in reducing exacerbations and symptoms in people with severe allergic and eosinophilic asthma, respectively. However, these therapies are not appropriate for 30-50% of patients in severe asthma clinics who present with non-allergic, non-eosinophilic, "type-2 low" asthma. These patients constitute an important and common clinical asthma phenotype, driven by distinct, yet poorly understood pathobiological mechanisms. In this review we describe the heterogeneity and clinical characteristics of type-2 low asthma and summarise current knowledge on the underlying pathobiological mechanisms, which includes neutrophilic airway inflammation often associated with smoking, obesity and occupational exposures and may be driven by persistent bacterial infections and by activation of a recently described IL-6 pathway. We review the evidence base underlying existing treatment options for specific treatable traits that can be identified and addressed. We focus particularly on severe asthma as opposed to difficult-to-treat asthma, on emerging data on the identification of airway bacterial infection, on the increasing evidence base for the use of long-term low-dose macrolides, a critical appraisal of bronchial thermoplasty, and evidence for the use of biologics in type-2 low disease. Finally, we review ongoing research into other pathways including tumour necrosis factor, IL-17, resolvins, apolipoproteins, type I interferons, IL-6 and mast cells. We suggest that type-2 low disease frequently presents opportunities for identification and treatment of tractable clinical problems; it is currently a rapidly evolving field with potential for the development of novel targeted therapeutics.

The Fungal Microbiome and Asthma

Asthma is a group of inflammatory conditions that compromises the airways of a continuously increasing number of people around the globe. Its complex etiology comprises both genetic and environmental aspects, with the intestinal and lung microbiomes emerging as newly implicated factors that can drive and aggravate asthma. Longitudinal infant cohort studies combined with mechanistic studies in animal models have identified microbial signatures causally associated with subsequent asthma risk. The recent inclusion of fungi in human microbiome surveys has revealed that microbiome signatures associated with asthma risk are not limited to bacteria, and that fungi are also implicated in asthma development in susceptible individuals. In this review, we examine the unique properties of human-associated and environmental fungi, which confer them the ability to influence immune development and allergic responses. The important contribution of fungi to asthma development and exacerbations prompts for their inclusion in current and future asthma studies in humans and animal models.

Investigating the effect of TRPV4 inhibition on pulmonary-vascular barrier permeability following segmental endotoxin challenge

BACKGROUND

Acute Respiratory Distress Syndrome (ARDS) is associated with increased pulmonary-vascular permeability. In the lung, transient receptor potential vanilloid 4 (TRPV4), a Ca²⁺-permeable cation channel, is a regulator of endothelial permeability and pulmonary edema. We performed a Phase I, placebo-controlled, double-blind, randomized, parallel group, proof-of-mechanism study to investigate the effects of TRPV4 channel blocker, GSK2798745, on pulmonary-vascular barrier permeability using a model of lipopolysaccharide (LPS)-induced lung inflammation.

METHODS

Healthy participants were randomized 1:1 to receive 2 single doses of GSK2798745 or placebo, 12 h apart. Two hours after the first dose, participants underwent bronchoscopy and segmental LPS instillation. Total protein concentration and neutrophil counts were measured in bronchoalveolar lavage (BAL) samples collected before and 24 h after LPS challenge, as markers of barrier permeability and inflammation, respectively. The primary endpoint was baseline adjusted total protein concentration in BAL at 24 h after LPS challenge. A Bayesian framework was used to estimate the posterior probability of any percentage reduction (GSK2798745 relative to placebo). Safety endpoints included the incidence of adverse events (AEs), vital signs, 12-lead electrocardiogram, clinical laboratory and haematological evaluations, and spirometry.

RESULTS

Forty-seven participants were dosed and 45 completed the study (22 on GSK2798745 and 23 on placebo). Overall, GSK2798745 was well tolerated. Small reductions in mean baseline adjusted BAL total protein (~9%) and neutrophils (~7%) in the LPS-challenged segment were observed in the GSK2798745 group compared with the placebo group; however, the reductions did not meet pre-specified success criteria of at least a 95% posterior probability that the percentage reduction in the mean 24-h post LPS BAL total protein level (GSK2798745 relative to placebo) exceeded zero. Median plasma concentrations of GSK2798745 were predicted to inhibit TRPV4 on lung vascular endothelial cells by ~70-85% during the 24 h after LPS challenge; median urea-corrected BAL concentrations of GSK2798745 were 3.0- to 8.7-fold higher than those in plasma.

CONCLUSIONS

GSK2798745 did not affect segmental LPS-induced elevation of BAL total protein or neutrophils, despite blood and lung exposures that were predicted to be efficacious. CLINICALTRIALS.

GOV IDENTIFIER

NCT03511105.

Understanding the immunology of asthma: Pathophysiology, biomarkers, and treatments for asthma endotypes

Asthma is a common disease in paediatrics and adults with a significant morbidity, mortality, and financial burden worldwide. Asthma is now recognized as a heterogeneous disease and emerging clinical and laboratory research has elucidated understanding of asthma's underlying immunology. The future of asthma is classifying asthma by endotype through connecting discernible characteristics with immunological mechanisms. This comprehensive review of the immunology of asthma details the currently known pathophysiology and clinical practice biomarkers in addition to forefront biologic and targeted therapies for all of the asthma endotypes. By understanding the immunology of asthma, practitioners will be able to diagnose patients by asthma endotype and provide personalized, biomarker-driven treatments to effectively control patients' asthma.

Targeting neutrophils in asthma: A therapeutic opportunity?

Suppression of airway inflammation with inhaled corticosteroids has been the key therapeutic approach for asthma for many years. Identification of inflammatory phenotypes in asthma has moreover led to important breakthroughs, e.g. with specific targeting of the IL-5 pathway as add-on treatment in difficult-to-treat eosinophilic asthma. However, the impact of interfering with the neutrophilic component in asthma is less documented and understood. This review provides an overview of established and recent insights with regard to the role of neutrophils in asthma, focusing on research in humans. We will describe the main drivers of neutrophilic responses in asthma, the heterogeneity in neutrophils and how they could contribute to asthma pathogenesis. Moreover we will describe findings from clinical trials, in which neutrophilic inflammation was targeted. It is clear that neutrophils are important actors in asthma development and play a role in exacerbations. However, more research is required to fully understand how modulation of neutrophil activity could lead to a significant benefit in asthma patients with airway neutrophilia.

Precision medicine in atopic diseases

PURPOSE OF REVIEW

To analyze the status of precision medicine in atopic diseases.

RECENT FINDINGS

Atopic diseases are increasingly recognized as heterogeneous in nature and they can be quite different in severity, response to therapy, triggers, genetic back ground, ancestral risk and type of inflammation. This significant variability in the landscape of atopic diseases is not reflected in the common treatment guidelines that follow 'one fits all' approach for their management. Such an approach is largely based on minimal 'phenotype' elements, such as severity of disease and response to therapy and does not reflect the information accumulate in the last 20 years about particular pathogenic pathways (endotypes) leading to disease (phenotypes) based on biomolecular analysis of the single individuals. Accumulating data have defined asthma allergic rhinitis, food allergy based on their endotypes and clinically relevant phenotypes. In general, atopic diseases can be largely classified as high or low Th2 inflammatory status, which may explain the severity and response to therapy.

SUMMARY

Precision medicine is aiming to use known endotype phenotype to guide specific individualized treatment. The work aimed in deep characterization of diseases to guide the disease management is crucial in light of the availability of ever more precise treatment able to target specific pathways.

Human lipopolysaccharide models provide mechanistic and therapeutic insights into systemic and pulmonary inflammation

Inflammation is a key feature in the pathogenesis of sepsis and acute respiratory distress syndrome (ARDS). Sepsis and ARDS continue to be associated with high mortality. A key contributory factor is the rudimentary understanding of the early events in pulmonary and systemic inflammation in humans, which are difficult to study in clinical practice, as they precede the patient's presentation to medical services. Lipopolysaccharide (LPS), a constituent of the outer membrane of Gram-negative bacteria, is a trigger of inflammation and the dysregulated host response in sepsis. Human LPS models deliver a small quantity of LPS to healthy volunteers, triggering an inflammatory response and providing a window to study early inflammation in humans. This allows biological/mechanistic insights to be made and new therapeutic strategies to be tested in a controlled, reproducible environment from a defined point in time. We review the use of human LPS models, focussing on the underlying mechanistic insights that have been gained by studying the response to intravenous and pulmonary LPS challenge. We discuss variables that may influence the response to LPS before considering factors that should be considered when designing future human LPS studies.

Regeneration and repair in the healing lung

The lung achieves an efficient gas exchange between a complex non‐sterile atmosphere and the body via a delicate and extensive epithelial surface, with high efficiency because of elastic deformation allowing for an increase and decrease in volume during the process of breathing and because of an extensive vasculature which aids rapid gas diffusion. The lungs’ large surface area exposes the organ to a continual risk of damage from pathogens, toxins or irritants; however, lung damage can be rapidly healed via regenerative processes that restore its structure and function. In response to sustained and extensive damage, the lung is healed via a non‐regenerative process resulting in scar tissue which locally stiffens its structure, which over time leads to a serious loss of lung function and to increasing morbidities. This review discusses what is known about the factors which influence whether a lung is healed by regeneration or repair and what potential new therapeutic approaches may positively influence lung healing.

Mechanisms and therapeutic strategies for non-T2 asthma

Non-T2 asthma is traditionally defined as asthma without features of T2 asthma. The definition is arbitrary and is generally based on the presence of neutrophils in sputum, or the absence (or normal levels) of eosinophils or other T2 markers in sputum (paucigranulocytic), airway biopsies or in blood. This definition may be imprecise as we gain more knowledge from applying transcriptomics and proteomics to blood and airway samples. The prevalence of non-T2 asthma is also difficult to estimate as most studies are cross-sectional and influenced by concomitant treatment with glucocorticosteroids, and by the presence of recognized or unrecognized airway infections. No specific therapies have shown any clinical benefits in patients with asthma that is associated with a non-T2 inflammatory process. It remains to be seen if such an endotype truly exists and to identify treatments to target that endotype. Meanwhile, identifying intense airway neutrophilia as an indicator of airway infection and airway hyperresponsiveness as an indicator of smooth muscle dysfunction, and treating them appropriately, and not increasing glucocorticosteroids in patients who do not have obvious T2 inflammation, seem reasonable.

Evidence Supporting a Phased Immuno-physiological Approach to COVID-19 From Prevention Through Recovery

This paper presents an evidence-based strategy for improving clinical outcomes in COVID-19. Recommendations are based on the phases of the disease, because optimal interventions for one phase may not be appropriate for a different phase. The four phases addressed are: Prevention, Infection, Inflammation and Recovery. Underlying this phased approach is recognition of emerging evidence for two different components of pathophysiology, early infection and late stage severe complications. These two aspects of the disease suggest two different patterns of clinical emphasis that seem on the surface to be not entirely concordant. We describe the application of therapeutic strategies and appropriate tactics that address four main stages of disease progression for COVID-19. Emerging evidence in COVID-19 suggests that the SARS-CoV-2 virus may both evade the innate immune response and kill macrophages. Delayed innate immune response and a depleted population of macrophages can theoretically result in a blunted antigen presentation, delaying and diminishing activation of the adaptive immune response. Thus, one clinical strategy involves supporting patient innate and adaptive immune responses early in the time course of illness, with the goal of improving the timeliness, readiness, and robustness of both the innate and adaptive immune responses. At the other end of the disease pathology spectrum, risk of fatality in COVID-19 is driven by excessive and persistent upregulation of inflammatory mechanisms associated with cytokine storm. Thus, the second clinical strategy is to prevent or mitigate excessive inflammatory response to prevent the cytokine storm associated with high mortality risk. Clinical support for immune system pathogen clearance mechanisms involves obligate activation of immune response components that are inherently inflammatory. This puts the goals of the first clinical strategy (immune activation) potentially at odds with the goals of the second strategy(mitigation of proinflammatory effects). This creates a need for discernment about the time course of the illness and with that, understanding of which components of an overall strategy to apply at each phase of the time course of the illness. We review evidence from early observational studies and the existing literature on both outcomes and mechanisms of disease, to inform a phased approach to support the patient at risk for infection, with infection, with escalating inflammation during infection, and at risk of negative sequelae as they move into recovery.

The Fungal Microbiome and Asthma

Asthma is a group of inflammatory conditions that compromises the airways of a continuously increasing number of people around the globe. Its complex etiology comprises both genetic and environmental aspects, with the intestinal and lung microbiomes emerging as newly implicated factors that can drive and aggravate asthma. Longitudinal infant cohort studies combined with mechanistic studies in animal models have identified microbial signatures causally associated with subsequent asthma risk. The recent inclusion of fungi in human microbiome surveys has revealed that microbiome signatures associated with asthma risk are not limited to bacteria, and that fungi are also implicated in asthma development in susceptible individuals. In this review, we examine the unique properties of human-associated and environmental fungi, which confer them the ability to influence immune development and allergic responses. The important contribution of fungi to asthma development and exacerbations prompts for their inclusion in current and future asthma studies in humans and animal models.

Serum IL-1β can be a biomarker in children with severe persistent allergic rhinitis

Background

Allergic rhinitis (AR) is one of the most common diseases globally and usually persists throughout life. In the present study, we aimed to determine whether the expression of inflammatory biomarkers has a relationship with the severity of allergic rhinitis and with comorbid asthma or other allergic diseases in children.

Methods

For diagnosis of AR, the skin prick test was performed to measure the responses to 18 allergens. Blood levels of eosinophils and immunoglobulin E (IgE) were examined. We classified the patients into 2 groups based on the severity of the condition as Group 1 [intermittent AR (IAR) or mild persistent AR (PAR)] and Group 2 (moderate to severe PAR). To determine the expression of inflammatory biomarkers, in serum and several biomarkers (caspase-1, IL-1β, CCL-11, CCL-24 and IL-33) were measured in the serum using enzyme-linked immunosorbent assay (ELISA). Additionally, we analyzed the correlation between clinical variables and the expression of biomarkers (eosinophils count, IL-1β and CCL-24) and the severity of AR.

Results

We found that eosinophils count, IL-1β, a marker of activation of inflammasomes, and CCL-24 were significantly increased in the moderate to severe PAR group (p = 0.008, p = 0.003, p = 0.039). Additionally, the expressions of eosinophil count, IL-1β and CCL-24 were significantly higher in patients with active asthmatic symptoms than in those without these conditions. On univariate analysis, allergic rhinitis in sibling, paternal allergic rhinitis, high expression of eosinophils count, IL-1β and CCL-24, history of active asthma and atopy correlated with severity of AR. Multivariate analysis showed only paternal allergic rhinitis and high expression of IL-1β as significant risk factors of moderate to severe PAR with 6.4 fold and 4.7 fold-increase in risk, respectively (p = 0.011 and p = 0.030).

Conclusion

In conclusion, this study provides the first evidence that an excessive release of biologically active IL-1β may promote inflammation in severe PAR. It demonstrates that IL-1β can be a biomarker for active allergic diseases such as AR, asthma, and atopy. Moreover, this finding suggests that IL-1B should be investigated as a therapeutic target in severe PAR and other allergic diseases.

Targeting Cytokines as Evolving Treatment Strategies in Chronic Inflammatory Airway Diseases

Cytokines are key players in the initiation and propagation of inflammation in chronic inflammatory airway diseases such as chronic obstructive pulmonary disease (COPD), bronchiectasis and allergic asthma. This makes them attractive targets for specific novel anti-inflammatory treatment strategies. Recently, both interleukin-1 (IL-1) and IL-6 have been associated with negative health outcomes, mortality and a pro-inflammatory phenotype in COPD. IL-6 in COPD was shown to correlate negatively with lung function, and IL-1beta was induced by cigarette smoke in the bronchial epithelium, causing airway inflammation. Furthermore, IL-8 has been shown to be a pro-inflammatory marker in bronchiectasis, COPD and allergic asthma. Clinical trials using specific cytokine blockade therapies are currently emerging and have contributed to reduce exacerbations and steroid use in COPD. Here, we present a review of the current understanding of the roles of cytokines in the pathophysiology of chronic inflammatory airway diseases. Furthermore, outcomes of clinical trials in cytokine blockade as novel treatment strategies for selected patient populations with those diseases will be discussed.

Non-eosinophilic asthma: current perspectives

Although non-eosinophilic asthma (NEA) is not the best known and most prevalent asthma phenotype, its importance cannot be underestimated. NEA is characterized by airway inflammation with the absence of eosinophils, subsequent to activation of non-predominant type 2 immunologic pathways. This phenotype, which possibly includes several not well-defined subphenotypes, is defined by an eosinophil count <2% in sputum. NEA has been associated with environmental and/or host factors, such as smoking cigarettes, pollution, work-related agents, infections, and obesity. These risk factors, alone or in conjunction, can activate specific cellular and molecular pathways leading to non-type 2 inflammation. The most relevant clinical trait of NEA is its poor response to standard asthma treatments, especially to inhaled corticosteroids, leading to a higher severity of disease and to difficult-to-control asthma. Indeed, NEA constitutes about 50% of severe asthma cases. Since most current and forthcoming biologic therapies specifically target type 2 asthma phenotypes, such as uncontrolled severe eosinophilic or allergic asthma, there is a dramatic lack of effective treatments for uncontrolled non-type 2 asthma. Research efforts are now focusing on elucidating the phenotypes underlying the non-type 2 asthma, and several studies are being conducted with new drugs and biologics aiming to develop effective strategies for this type of asthma, and various immunologic pathways are being scrutinized to optimize efficacy and to abolish possible adverse effects.

Multidimensional endotypes of chronic rhinosinusitis and their association with treatment outcomes

BACKGROUND

The expression of chronic rhinosinusitis (CRS) is multidimensional. Disease heterogeneity in patients with CRS remains poorly understood. This study aimed to identify endotypes of CRS using cluster analysis by integrating multidimensional characteristics and to explore their association with treatment outcomes.

METHODS

A total of 28 clinical variables and 39 mucosal cellular and molecular variables were analyzed using principal component analysis. Cluster analysis was performed on 246 prospectively recruited Chinese CRS patients with at least 1-year postoperative follow-up. Difficult-to-treat CRS was characterized in each generated cluster.

RESULTS

Seven subject clusters were identified. Cluster 1 (13.01%) was comparable to the classic well-defined eosinophilic CRS with polyps, having severe disease and the highest proportion of difficult-to-treat CRS. Patients in cluster 2 (16.26%) and cluster 4 (13.82%) had relatively lower proportions of presence of polyps and presented mild inflammation with moderate proportions of difficult-to-treat cases. Subjects in cluster 2 were highly atopic. Cluster 3 (7.31%) and cluster 6 (21.14%) were characterized by severe or moderate neutrophilic inflammation, respectively, and with elevated levels of IL-8 and high proportions of difficult-to-treat CRS. Cluster 5 (4.07%) was a unique group characterized by the highest levels of IL-10 and lacked difficult-to-treat cases. Cluster 7 (24.39%) demonstrated the lowest symptom severity, a low proportion of difficult-to-treat CRS, and low inflammation load. Finally, we found that difficult-to-treat CRS was associated with distinct clinical features and biomarkers in the different clusters.

CONCLUSIONS

Distinct clinicopathobiologic clusters of CRS display differences in clinical response to treatments and characteristics of difficult-to-treat CRS.

Obesity-Related Asthma: Immune Regulation and Potential Targeted Therapies

Obesity, one of the most severe public health problems of the 21st century, is a common metabolic syndrome due to excess body fat. The incidence and severity of obesity-related asthma have undergone a dramatic increase. Because obesity-related asthma is poorly controlled using conventional therapies, alternative and complementary therapies are urgently needed. Lipid metabolism may be abnormal in obesity-related asthma, and immune modulation therapies need to be investigated. Herein, we describe the immune regulators of lipid metabolism in obesity as well as the interplay of obesity and asthma. These lay the foundations for targeted therapies in terms of direct and indirect immune regulators of lipid metabolism, which ultimately help provide effective control of obesity-related asthma with a feasible treatment strategy.