TSLP Inhibitors for Asthma: Current Status and Future Prospects

Exploring the therapeutic potential of monoclonal antibodies targeting TSLP and IgE in asthma management

BACKGROUND

In recent years, there has been a growing interest in the utilization of biologic therapies for the management of asthma. Both TSLP and IgE are important immune molecules in the development of asthma, and they are involved in the occurrence and regulation of inflammatory response.

METHODS

A comprehensive search of PubMed and Web of Science was conducted to gather information on anti-TSLP antibody and anti-IgE antibody.

RESULTS

This investigation elucidates the distinct mechanistic roles of Thymic Stromal Lymphopoietin (TSLP) and Immunoglobulin E (IgE) in the pathogenesis of asthma, with a particular emphasis on delineating the therapeutic mechanisms and pharmacological properties of monoclonal antibodies targeting IgE and TSLP. Through a meticulous examination of clinical trials involving paradigmatic agents such as omalizumab and tezepelumab, we offer valuable insights into the potential treatment modalities for diseases with shared immunopathogenic pathways involving IgE and TSLP.

CONCLUSION

The overarching objective of this comprehensive study is to delve into the latest advancements in asthma therapeutics and to provide guidance for future investigations in this domain.

Pathogenic roles of follicular helper T cells in IgG4-related disease and implications for potential therapy

IgG4-related disease (IgG4-RD) is a recently described autoimmune disorder characterized by elevated serum IgG4 levels and tissue infiltration of IgG4+ plasma cells in multiple organ systems. Recent advancements have significantly enhanced our understanding of the pathological mechanism underlying this immune-mediated disease. T cell immunity plays a crucial role in the pathogenesis of IgG4-RD, and follicular helper T cells (Tfh) are particularly important in germinal center (GC) formation, plasmablast differentiation, and IgG4 class-switching. Apart from serum IgG4 concentrations, the expansion of circulating Tfh2 cells and plasmablasts may also serve as novel biomarkers for disease diagnosis and activity monitoring in IgG4-RD. Further exploration into the pathogenic roles of Tfh in IgG4-RD could potentially lead to identifying new therapeutic targets that offer more effective alternatives for treating this condition. In this review, we will focus on the current knowledge regarding the pathogenic roles Tfh cells play in IgG4-RD and outline potential therapeutic targets for future clinical intervention.

Gasdermin D silencing alleviates airway inflammation and remodeling in an ovalbumin-induced asthmatic mouse model

Emerging evidence demonstrates that pyroptosis has been implicated in the pathogenesis of asthma. Gasdermin D (GSDMD) is the pyroptosis executioner. The mechanism of GSDMD in asthma remains unclear. The aim of this study was to elucidate the potential role of GSDMD in asthmatic airway inflammation and remodeling. Immunofluorescence staining was conducted on airway epithelial tissues obtained from both asthma patients and healthy controls (HCs) to evaluate the expression level of N-GSDMD. ELISA was used to measure concentrations of cytokines (IL-1β, IL-18, IL-17A, and IL-10) in serum samples collected from asthma patients and healthy individuals. We demonstrated that N-GSDMD, IL-18, and IL-1β were significantly increased in samples with mild asthma compared with those from the controls. Then, wild type and Gsdmd-knockout (Gsdmd-/-) mice were used to establish asthma model. We performed histopathological staining, ELISA, and flow cytometry to explore the function of GSDMD in allergic airway inflammation and tissue remodeling in vivo. We observed that the expression of N-GSDMD, IL-18, and IL-1β was enhanced in OVA-induced asthma mouse model. Gsdmd knockout resulted in attenuated IL-18, and IL-1β production in both bronchoalveolar lavage fluid (BALF) and lung tissue in asthmatic mice. In addition, Gsdmd-/- mice exhibit a significant reduction in airway inflammation and remodeling, which might be associated with reduced Th17 inflammatory response and M2 polarization of macrophages. Further, we found that GSDMD knockout may improve asthmatic airway inflammation and remodeling through regulating macrophage adhesion, migration, and macrophage M2 polarization by targeting Notch signaling pathway. These findings demonstrate that GSDMD deficiency profoundly alleviates allergic inflammation and tissue remodeling. Therefore, GSDMD may serve as a potential therapeutic target against asthma.

Tezepelumab in a case of severe asthma exacerbation and influenza-pneumonia on VV-ECMO

We present a case of 43-year-old male patient with broadly by Omalizumab, Mepolizumab and Benralizumab pretreated allergic asthma, who suffered a near fatal exacerbation, triggered by an influenza A infection. Due to massive bronchoconstriction with consecutive hypercapnic ventilatory failure veno-venous ECMO therapy had to be implemented. Hence, guideline directed asthma therapy a substantial bronchodilatation could not be achieved. After administration of a single dose Tezepelumab, a novel TLSP-inhibitor, and otherwise unchanged therapy we documented a significant reduction in intrinsic PEEP measured via a naso-gastric balloon catheter and a narrowing in the expiratory flow curve of the ventilator within 24 hours. The consecutive ventilatory improvement allowed the successful weaning from veno-venous ECMO therapy and invasive ventilation.

Investigational thymic stromal lymphopoietin inhibitors for the treatment of asthma: a systematic review

INTRODUCTION

Severe asthma patients often remain uncontrolled despite high-intensity therapies. Biological therapies targeting thymic stromal lymphopoietin (TSLP), a key player in asthma pathogenesis, have emerged as potential options. Currently, the only TSLP inhibitor approved for the treatment of severe asthma is the immunoglobulin G (IgG) 2λ anti-TSLP monoclonal antibody (mAb) tezepelumab.

AREAS COVERED

This systematic review assesses the efficacy and safety of investigational TSLP inhibitors across different stages of development for asthma treatment.

EXPERT OPINION

TSLP contributes to airway inflammation, making it a pivotal therapeutic target. Ecleralimab, an inhaled antibody fragment antigen binding, shows promising evidence in enhancing efficacy and reducing systemic adverse events. SAR443765, with its NANOBODY® formulation and bispecific inhibition of TSLP and IL-13, offers improved tissue penetration and efficacy. The mAB TQC2731 exhibits high in vitro bioactivity, and the strength of the mAb UPB-101 is to act against the TSLP receptor. Some studies include mild and moderate asthma patients, suggesting the potential for extending biological therapy to non-severe patients. This systematic review highlights the potential of TSLP inhibitors as valuable additions to asthma treatment, even in milder forms of the disease. Future research and cost-reduction efforts are needed to expanding access to these promising therapies.

Development and characterization of anti-IL-5 monoclonal antibody Fab fragment for blocking IL-5/IL-5Rα binding

Interleukin-5 (IL-5) is a homodimeric cytokine that is a crucial regulator of the proliferation, activation, and maturation of eosinophils. Anti-IL-5 monoclonal antibodies, which block the binding of IL-5 to the IL-5 receptor subunit alpha (IL-5Rα), have been successfully used to treat eosinophilic (EOS) asthma. The currently marketed monoclonal antibody drugs require repeated injections for administration, which seriously affect patient compliance and high systemic exposure for injectable drug delivery. Here we successfully screened and developed the Fab (fragment of antigen binding), which is 1/3rd the molecular weight of IgG, favoring inhalation-mediated delivery to the lungs, making it more effective for asthma treatment. The 20A12-Fab-H12L3 can bind to IL-5 with a binding constant of 1.236E-09 M while significantly inhibiting the IL-5/IL-5Rα complex formation. We found that the light chain amino acids (S46 and F71) significantly affected the antibody expression during humanization. The 20A12-Fab-H12L3 significantly inhibited the proliferation of TF-1 cells and blocked the IL-5 binding to the IL-5Rα-overexpressing human embryonic kidney (HEK)-293 cells in vitro. Therefore, based on the mutant IL-5 binding with Fab, we explained why antibodies blocked IL-5 binding to IL-5Rα. Thus, this study provided a candidate pharmaceutical antibody for inhalation drug delivery.

Personalized and Precision Medicine in Asthma and Eosinophilic Esophagitis: The Role of T2 Target Therapy

The role of type 2 inflammation has been progressively associated with many diseases, including severe asthma, atopic dermatitis, nasal polyposis, eosinophilic granulomatosis with polyangiitis, and, recently, eosinophilic esophagitis. Despite this, the association between asthma and esophagitis is still poorly known, and this is probably because of the low prevalence of each disease and the even lower association between them. Nonetheless, observations in clinical trials and, subsequently, in real life, have allowed researchers to observe how drugs acting on type 2 inflammation, initially developed and marketed for severe asthma, could be effective also in treating eosinophilic esophagitis. For this reason, clinical trials specifically designed for the use of drugs targeted to type 2 inflammation were also developed for eosinophilic esophagitis. The results of clinical trials are presently promising and envisage the use of biologicals that are also likely to be employed in the field of gastroenterology in the near future. This review focuses on the use of biologicals for type 2 inflammation in cases of combined severe asthma and eosinophilic esophagitis.

The emerging roles of SUMOylation in pulmonary diseases

Small ubiquitin-like modifier mediated modification (SUMOylation) is a critical post-translational modification that has a broad spectrum of biological functions, including genome replication and repair, transcriptional regulation, protein stability, and cell cycle progression. Perturbation or deregulation of a SUMOylation and deSUMOylation status has emerged as a new pathophysiological feature of lung diseases. In this review, we highlighted the link between SUMO pathway and lung diseases, especially the sumoylated substrate such as C/EBPα in bronchopulmonary dysplasia (BDP), PPARγ in pneumonia, TFII-I in asthma, HDAC2 in chronic obstructive pulmonary disease (COPD), KLF15 in hypoxic pulmonary hypertension (HPH), SMAD3 in idiopathic pulmonary fibrosis (IPF), and YTHDF2 in cancer. By exploring the impact of SUMOylation in pulmonary diseases, we intend to shed light on its potential to inspire the development of innovative diagnostic and therapeutic strategies, holding promise for improving patient outcomes and overall respiratory health.

The efficacy and safety of tezepelumab in the treatment of uncontrolled asthma: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Tezepelumab is a human thymic stromal lymphopoietin (TSLP) antibody with effects in asthma. Therefore, our study aimed to evaluate the overall efficacy and safety of tezepelumab for the treatment of uncontrolled asthma.

METHODS

The databases Cochrane Library, PubMed, Embase, Web of Science, and Clinical Trials were searched from inception to April 1, 2022. Only randomized controlled trial (RCTs) that evaluated tezepelumab and a comparator for treating uncontrolled asthma were included. Additionally, articles were limited to English. The primary outcome was clinical efficacy, and the secondary outcome was adverse events. The risk of bias and quality were assessed by the Cochrane Collaboration bias assessment tool. The meta-analysis was performed using Review Manager Version 5.3.

RESULTS

Four RCTs with a total of 1600 patients were included in the study. Pooled analysis indicated that tezepelumab had significantly decreased annualized asthma exacerbations (odds ratio [OR] = 0.67, 95% confidence interval [CI] = [0.57, -0.80], P < .00001) and the asthma control questionnaire score of 6 (ACQ-6) among the patients (standard mean difference [SMD] = -0.29, 95% CI = [-0.39, -0.20], P < .00001) compared to placebo. Furthermore, tezepelumab treatment significantly improved forced expiratory volume in 1 second (FEV1, SMD = 0.28, 95% CI = [0.11, 0.45], P = .001). Regarding safety, the pooled analysis indicated that patients treated with tezepelumab showed no significant difference in adverse events that led to discontinuation of the treatment, but they experienced some other (non-serious) adverse events compared to the placebo group. However, there was a significant decrease in the incidence of serious adverse events and any adverse events in the tezepelumab group. Tezepelumab use was associated with adverse events, including nasopharyngitis, headache, and bronchitis, despite effectively treating asthma.

CONCLUSION

Tezepelumab effectively improved FEV1, reduced the disease symptom score, and decreased the risk of exacerbations in uncontrolled asthma patients. Tezepelumab was associated with some adverse events compared to placebo. This suggests that careful management of adverse events is required if tezepelumab is used to treat asthma patients.

Revisiting asthma pharmacotherapy: where do we stand and where do we want to go?

Several current guidelines/strategies outline a treatment approach to asthma, which primarily consider the goals of improving lung function and quality of life and reducing symptoms and exacerbations. They suggest a strategy of stepping up or down treatment, depending on the patient's overall current asthma symptom control and future risk of exacerbation. While this stepwise approach is undeniably practical for daily practice, it does not always address the underlying mechanisms of this heterogeneous disease. In the last decade, there have been attempts to improve the treatment of severe asthma, such as the addition of a long-acting antimuscarinic agent to the traditional inhaled corticosteroid/long-acting β2-agonist treatment and the introduction of therapies targeting key cytokines. However, despite such strategies several unmet needs in this population remain, motivating research to identify novel targets and develop improved therapeutic and/or preventative asthma treatments. Pending the availability of such therapies, it is essential to re-evaluate the current conventional "one-size-fits-all" approach to a more precise asthma management. Although challenging, identifying "treatable traits" that contribute to respiratory symptoms in individual patients with asthma may allow a more pragmatic approach to establish more personalised therapeutic goals.

Effects of Tezepelumab on Quality of Life of Patients with Moderate-to-Severe, Uncontrolled Asthma: Systematic Review and Meta-Analysis

PURPOSE OF REVIEW

To assess the effects of tezepelumab on quality of life (QoL) in patients with moderate-to-severe, uncontrolled asthma.

RECENT FINDINGS

Tezepelumab improves pulmonary function tests (PFTs) and reduces the annualized asthma exacerbation rate (AAER) in patients with moderate-to-severe, uncontrolled asthma. We searched MEDLINE, Embase, and Cochrane Library from inception to September 2022. We included randomized controlled trials comparing tezepelumab versus placebo in patients aged ≥ 12 years with asthma on medium- or high-dose inhaled corticosteroids with ≥ 1 additional controller medication for ≥ 6 months and who had ≥ 1 asthma exacerbation in the 12 months before enrollment. We estimated effects measures with a random-effects model. Of 239 records identified, three studies were included, with a total of 1,484 patients. Tezepelumab significantly decreased biomarkers of T helper 2-driven inflammation, including blood eosinophil count (MD -135.8 [95% CI -164.37, -107.23]) and fractional exhaled nitric oxide (MD -9.64 [95% CI -13.75, -5.53]); improved PFTs, including pre-bronchodilator forced expiratory volume in 1 s (MD 0.18 [95% CI 0.08-0.27]); reduced the AAER (MD 0.47 [95% CI 0.39-0.56]); improved asthma-specific health-related QoL in the Asthma Control Questionnaire-6 (MD -0.33 [95% CI -0.34, -0.32]), Asthma Quality of Life Questionnaire for 12 Years and Older (MD 0.34 [95% CI 0.33, -0.35]), Asthma Symptom Diary (MD -0.11 [95% CI -0.18, -0.04]), and European Quality of Life 5 Dimensions 5 Levels Questionnaire (SMD 3.29 [95% CI 2.03, 4.55]) scores, although not clinically important; and did not change key safety outcomes, including any adverse event (OR 0.78 [95% CI 0.56-1.09]).

A CpG-Oligodeoxynucleotide Suppresses Th2/Th17 Inflammation by Inhibiting IL-33/ST2 Signaling in Mice from a Model of Adoptive Dendritic Cell Transfer of Smoke-Induced Asthma

Tobacco smoke exposure is a major environmental risk factor that facilitates the development and progression of asthma. Our previous study showed that CpG oligodeoxynucleotide (CpG-ODN) inhibits thymic stromal lymphopoietin (TSLP)-dendritic cells (DCs) to reduce Th2/Th17-related inflammatory response in smoke-related asthma. However, the mechanism underlying CpG-ODN -downregulated TSLP remains unclear. A combined house dust mite (HDM)/cigarette smoke extract (CSE) model was used to assess the effects of CpG-ODN on airway inflammation, Th2/Th17 immune response, and amount of IL-33/ST2 and TSLP in mice with smoke-related asthma induced by adoptive transfer of bone-marrow-derived dendritic cells (BMDCs) and in the cultured human bronchial epithelium (HBE) cells administered anti-ST2, HDM, and/or CSE. In vivo, compared to the HDM alone model, the combined HDM/CSE model had aggravated inflammatory responses, while CpG-ODN attenuated airway inflammation, airway collagen deposition, and goblet cell hyperplasia and reduced the levels of IL-33/ST2, TSLP, and Th2/Th17-cytokines in the combined model. In vitro, IL-33/ST2 pathway activation promoted TSLP production in HBE cells, which could be inhibited by CpG-ODN. CpG-ODN administration alleviated Th2/Th17 inflammatory response, decreased the infiltration of inflammatory cells into the airway, and improved the remodeling of smoke-related asthma. The underlying mechanism may be that CpG-ODN inhibits the TSLP-DCs pathway by downregulating the IL-33/ST2 axis.

Development of an inhaled anti-TSLP therapy for asthma

Thymic stromal lymphopoietin (TSLP), an epithelial cell-derived cytokine, acts as a key mediator in airway inflammation and modulates the function of multiple cell types, including dendritic cells and group 2 innate lymphoid cells. TSLP plays a role in asthma pathogenesis as an upstream cytokine, and data suggest that TSLP blockade with the anti-TSLP monoclonal antibody, tezepelumab, could be efficacious in a broad asthma population. Currently approved asthma biologic therapies target allergic or eosinophilic disease and require phenotyping; therefore, an unmet need exists for a therapy that can address Type 2 (T2)-high and T2-low inflammation in asthma. All currently approved biologic treatments are delivered intravenously or subcutaneously; an inhaled therapy route that allows direct targeting of the lung with reduced systemic impact may offer advantages. Currently in development, ecleralimab (CSJ117) represents the first inhaled anti-TSLP antibody fragment that binds soluble TSLP and prevents TSLP receptor activation, thereby inhibiting further inflammatory signalling cascades. This anti-TSLP antibody fragment is being developed for patients with severe uncontrolled asthma despite standard of care inhaled therapy. A Phase IIa proof of concept study, using allergen bronchoprovocation as a model for asthma exacerbations, found that ecleralimab was well-tolerated and reduced allergen-induced bronchoconstriction in adult patients with mild asthma. These results suggest ecleralimab may be a promising, new therapeutic class for asthma treatment.

Biologic therapies for chronic obstructive pulmonary disease

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a disorder characterized by a complicated chronic inflammatory response that is resistant to corticosteroid therapy. As a result, there is a critical need for effective anti-inflammatory medications to treat people with COPD. Using monoclonal antibodies (mAbs) to inhibit cytokines and chemokines or their receptors could be a potential approach to treating the inflammatory component of COPD.

AREAS COVERED

The therapeutic potential that some of these mAbs might have in COPD is reviewed.

EXPERT OPINION

No mAb directed against cytokines or chemokines has shown any therapeutic impact in COPD patients, apart from mAbs targeting the IL-5 pathway that appear to have statistically significant, albeit weak, effect in patients with eosinophilic COPD. This may reflect the complexity of COPD, in which no single cytokine or chemokine has a dominant role. Because the umbrella term COPD encompasses several endotypes with diverse underlying processes, mAbs targeting specific cytokines or chemokines should most likely be evaluated in limited and focused populations.

Genetic Variants Associated with Bronchial Asthma Specific to the Population of the Russian Federation

Bronchial asthma (BA) is a disease that still lacks an exhaustive treatment protocol. In this regard, the global medical community pays special attention to the genetic prerequisites for the occurrence of this disease. Therefore, the search for the genetic polymorphisms underlying bronchial asthma has expanded considerably. As the present study progressed, a significant amount of scientific medical literature was analyzed and 167 genes reported to be associated with the development of bronchial asthma were identified. A group of participants (n = 7,303) who had voluntarily provided their biomaterial (venous blood) to be used in the research conducted by the Federal Medical Biological Agency of Russia was formed to subsequently perform a bioinformatic verification of known associations and search for new ones. This group of participants was divided into four cohorts, including two sex-distinct cohorts of individuals with a history of asthma and two sex-distinct cohorts of apparently healthy individuals. A search for polymorphisms was made in each cohort among the selected genes, and genetic variants were identified whose difference in occurrence in the different cohorts was statistically significant (significance level less than 0.0001). The study revealed 11 polymorphisms that affect the development of asthma: four genetic variants (rs869106717, rs1461555098, rs189649077, and rs1199362453), which are more common in men with bronchial asthma compared to apparently healthy men; five genetic variants (rs1923038536, rs181066119, rs143247175, rs140597386, and rs762042586), which are more common in women with bronchial asthma compared to apparently healthy women; and two genetic variants (rs1219244986 and rs2291651) that are rare in women with a history of asthma.

IL1RAP expression and the enrichment of IL-33 activation signatures in severe neutrophilic asthma

BACKGROUND

Interleukin (IL)-33 is an upstream regulator of type 2 (T2) eosinophilic inflammation and has been proposed as a key driver of some asthma phenotypes.

OBJECTIVE

To derive gene signatures from in vitro studies of IL-33-stimulated cells and use these to determine IL-33-associated enrichment patterns in asthma.

METHODS

Signatures downstream of IL-33 stimulation were derived from our in vitro study of human mast cells and from public datasets of in vitro stimulated human basophils, type 2 innate lymphoid cells (ILC2), regulatory T cells (Treg) and endothelial cells. Gene Set Variation Analysis (GSVA) was used to probe U-BIOPRED and ADEPT sputum transcriptomics to determine enrichment scores (ES) for each signature according to asthma severity, sputum granulocyte status and previously defined molecular phenotypes.

RESULTS

IL-33-activated gene signatures were cell-specific with little gene overlap. Individual signatures, however, were associated with similar signalling pathways (TNF, NF-κB, IL-17 and JAK/STAT signalling) and immune cell differentiation pathways (Th17, Th1 and Th2 differentiation). ES for IL-33-activated gene signatures were significantly enriched in asthmatic sputum, particularly in patients with neutrophilic and mixed granulocytic phenotypes. IL-33 mRNA expression was not elevated in asthma whereas the expression of mRNA for IL1RL1, the IL-33 receptor, was up-regulated in the sputum of severe eosinophilic asthma. The mRNA expression for IL1RAP, the IL1RL1 co-receptor, was greatest in severe neutrophilic and mixed granulocytic asthma.

CONCLUSIONS

IL-33-activated gene signatures are elevated in neutrophilic and mixed granulocytic asthma corresponding with IL1RAP co-receptor expression. This suggests incorporating T2-low asthma in anti-IL-33 trials.

Thymic stromal lymphopoietin levels after allogeneic hematopoietic stem cell transplantation

BACKGROUND

Thymic stromal lymphopoietin (TSLP) is an immunoregulatory, Th2-polarizing cytokine produced by epithelial cells. We hypothesized that TSLP affects immune reconstitution after hematopoietic stem cell transplantation (HSCT) leading to increased alloreactivity.

METHODS

We measured plasma TSLP by ELISA in 38 patients and assessed the immune reconstitution by flow cytometry.

RESULTS

TSLP levels rose after initiation of the conditioning to peak at day +21 after HSCT (p = .03), where TSLP levels correlated with counts of neutrophils (rho = 0.36, p = .04), monocytes (rho = 0.58, p = .006), and lymphocytes (rho = 0.59, p = .02). Overall absolute TSLP levels were not associated with acute or chronic graft-vs-host disease (a/cGvHD). However, patients mounting a sustained increase in TSLP levels at day +90 had a higher risk of cGvHD compared to patients who had returned to pre-conditioning levels at that stage (cumulative incidence: 77% vs. 38%, p = .01).

CONCLUSION

In conclusion, this study suggests a role of TSLP in immune reconstitution and alloreactivity post-HSCT. lymphopoietin (TSLP) is an immunoregulatory, Th2-polarizing cytokine produced by epithelial cells. We hypothesized that TSLP affects immune reconstitution after hematopoietic stem cell transplantation (HSCT) leading to increased alloreactivity. We measured plasma TSLP by ELISA in 38 patients and assessed the immune reconstitution by flow cytometry.

Expression of Thymic Stromal Lymphopoietin in Immune-Related Dermatoses

Thymic stromal lymphopoietin (TSLP), long known to be involved in Th2 response, is also implicated in multiple inflammatory dermatoses and cancers. The purpose of this study was to improve our understanding of the expression of TSLP in the skin of those dermatoses. Lesional specimens of representative immune-related dermatoses, including lichen planus (LP), discoid lupus erythematosus (DLE), eczema, bullous pemphigoid (BP), psoriasis vulgaris (PsV), sarcoidosis, and mycosis fungoides (MF), were retrospectively collected and analyzed by immunohistochemistry. Morphologically, TSLP was extensively expressed in the epidermis of each dermatosis, but the expression was weak in specimens of DLE. In a semiquantitative analysis, TSLP was significantly expressed in the epidermis in LP, BP, eczema, PsV, sarcoidosis, and MF. TSLP expression was higher in the stratum spinosum in LP, eczema, BP, PsV, and MF and higher in the stratum basale in sarcoidosis and PsV. Moreover, we found positive TSLP staining in the dermal infiltrating inflammatory cells of BP, PsV, and sarcoidosis. Our observation of TSLP in different inflammatory dermatoses might provide a novel understanding of TSLP in the mechanism of diseases with distinctly different immune response patterns and suggest a potential novel therapeutic target of those diseases.

Molecular and Immunomodulatory Actions of New Antiasthmatic Agents: Exploring the Diversity of Biologics in Th2 Endotype Asthma

Asthma is a major respiratory disorder characterised by chronic inflammation and airway remodelling. It affects about 1-8% of the global population and is responsible for over 461,000 deaths annually. Until recently, the pharmacotherapy of severe asthma involved high doses of inhaled corticosteroids in combination with β-agonist for prolonged action, including theophylline, leukotriene antagonist or anticholinergic yielding limited benefit. Although the use of newer agents to target Th2 asthma endotypes has improved therapeutic outcomes in severe asthmatic conditions, there seems to be a paucity of understanding the diverse mechanisms through which these classes of drugs act. This article delineates the molecular and immunomodulatory mechanisms of action of new antiasthmatic agents currently being trialled in preclinical and clinical studies to remit asthmatic conditions. The ultimate goal in developing antiasthmatic agents is based on two types of approaches: either anti-inflammatory or bronchodilators. Biologic and most small molecules have been shown to modulate specific asthma endotypes, targeting thymic stromal lymphopoietin, tryptase, spleen tyrosine kinase (Syk), Janus kinase, PD-L1/PD-L2, GATA-3, and CD38 for the treatment and management of Th2 endotype asthma.

Heterogeneity of ILC2s in the Intestine; Homeostasis and Pathology

Group 2 innate lymphoid cells (ILC2s) were identified in 2010 as a novel lymphocyte subset lacking antigen receptors, such as T-cell or B-cell receptors. ILC2s induce local immune responses characterized by producing type 2 cytokines and play essential roles for maintaining tissue homeostasis. ILC2s are distributed across various organs, including the intestine where immune cells are continuously exposed to external antigens. Followed by luminal antigen stimulation, intestinal epithelial cells produce alarmins, such as IL-25, IL-33, and thymic stromal lymphopoietin, and activate ILC2s to expand and produce cytokines. In the context of parasite infection, the tuft cell lining in the epithelium has been revealed as a dominant source of intestinal IL-25 and possesses the capability to regulate ILC2 homeostasis. Neuronal systems also regulate ILC2s through neuropeptides and neurotransmitters, and interact with ILC2s bidirectionally, a process termed “neuro-immune crosstalk”. Activated ILC2s produce type 2 cytokines, which contribute to epithelial barrier function, clearance of luminal antigens and tissue repair, while ILC2s are also involved in chronic inflammation and tissue fibrosis. Recent studies have shed light on the contribution of ILC2s to inflammatory bowel diseases, mainly comprising ulcerative colitis and Crohn’s disease, as defined by chronic immune activation and inflammation. Modern single-cell analysis techniques provide a tissue-specific picture of ILC2s and their roles in regulating homeostasis in each organ. Particularly, single-cell analysis helps our understanding of the uniqueness and commonness of ILC2s across tissues and opens the novel research area of ILC2 heterogeneity. ILC2s are classified into different phenotypes depending on tissue and phase of inflammation, mainly inflammatory and natural ILC2 cells. ILC2s can also switch phenotype to ILC1- or ILC3-like subsets. Hence, recent studies have revealed the heterogeneity and plasticity of ILC2, which indicate dynamicity of inflammation and the immune system. In this review, we describe the regulatory mechanisms, function, and pathological roles of ILC2s in the intestine.

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.

Specific Therapy for T2 Asthma

Asthma is a disease with high incidence and prevalence, and its severe form accounts for approximately 10% of asthmatics. Over the last decade, the increasing knowledge of the mechanisms underlying the disease allowed the development of biological drugs capable of sufficiently controlling symptoms and reducing the use of systemic steroids. The best-known mechanisms are those pertaining to type 2 inflammation, for which drugs were developed and studied. Those biological treatments affect crucial points of bronchial inflammation. Among the mechanisms explored, there were IgE (Omalizumab), interleukin 5 (Mepolizumab and Reslizumab), interleukin 5 receptor alpha (Benralizumab) and interleukin 4/13 receptor (Dupilumab). Under investigation and expected to be soon commercialized is the monoclonal antibody blocking the thymic stromal lymphopoietin (Tezepelumab). Seemingly under study and promising, are anti-interleukin-33 (itepekimab) and anti-suppressor of tumorigenicity-2 (astegolimab). With this study, we want to provide an overview of these drugs, paying particular attention to their mechanism of action, the main endpoints reached in clinical trials, the main results obtained in real life and some unclear points regarding their usage.

A New Comprehensive Approach to Assess the Probability of Success of Development Programs Before Pivotal Trials

The point at which clinical development programs transition from early phase to pivotal trials is a critical milestone. Substantial uncertainty about the outcome of pivotal trials may remain even after seeing positive early phase data, and companies may need to make difficult prioritization decisions for their portfolio. The probability of success (PoS) of a program, a single number expressed as a percentage reflecting the multitude of risks that may influence the final program outcome, is a key decision-making tool. Despite its importance, companies often rely on crude industry benchmarks that may be "adjusted" by experts based on undocumented criteria and which are typically misaligned with the definition of success used to drive commercial forecasts, leading to overly optimistic expected net present value calculations. We developed a new framework to assess the PoS of a program before pivotal trials begin. Our definition of success encompasses the successful outcome of pivotal trials, regulatory approval and meeting the requirements for market access as outlined in the target product profile. The proposed approach is organized in four steps and uses an innovative Bayesian approach to synthesize all relevant evidence. The new PoS framework is systematic and transparent. It will help organizations to make more informed decisions. In this paper, we outline the rationale and elaborate on the structure of the proposed framework, provide examples, and discuss the benefits and challenges associated with its adoption.

Synthesis and in vitro evaluation of anti-inflammatory, antioxidant, and anti-fibrotic effects of new 8-aminopurine-2,6-dione-based phosphodiesterase inhibitors as promising anti-asthmatic agents

Phosphodiesterase (PDE) inhibitors are currently an extensively studied group of compounds that can bring many benefits in the treatment of various inflammatory and fibrotic diseases, including asthma. Herein, we describe a series of novel N'-phenyl- or N'-benzylbutanamide and N'-arylidenebutanehydrazide derivatives of 8-aminopurine-2,6-dione (27-43) and characterized them as prominent pan-PDE inhibitors. Most of the compounds exhibited antioxidant and anti-inflammatory activity in lipopolysaccharide (LPS)-induced murine macrophages RAW264.7. The most active compounds (32-35 and 38) were evaluated in human bronchial epithelial cells (HBECs) derived from asthmatics. To better map the bronchial microenvironment in asthma, HBECs after exposure to selected 8-aminopurine-2,6-dione derivatives were incubated in the presence of two proinflammatory and/or profibrotic factors: transforming growth factor type β (TGF-β) and interleukin 13 (IL-13). Compounds 32-35 and 38 significantly reduced both IL-13- and TGF-β-induced expression of proinflammatory and profibrotic mediators, respectively. Detailed analysis of their inhibition preferences for selected PDEs showed high affinity for isoenzymes important in the pathogenesis of asthma, including PDE1, PDE3, PDE4, PDE7, and PDE8. The presented data confirm that structural modifications within the 7 and 8 positions of the purine-2,6-dione core result in obtaining preferable pan-PDE inhibitors which in turn exert an excellent anti-inflammatory and anti-fibrotic effect in the bronchial epithelial cells derived from asthmatic patients. This dual-acting pan-PDE inhibitors constitute interesting and promising lead structures for further anti-asthmatic agent discovery.

An Overview of the Safety and Efficacy of Monoclonal Antibodies for the Chronic Obstructive Pulmonary Disease

Several mAbs have been tested or are currently under clinical evaluation for the treatment of COPD. They can be subdivided into those that aim to block specific pro-inflammatory and pro-neutrophilic cytokines and chemokines, such as TNF-α, IL-1β, CXCL8 and IL-1β, and those that act on T2-mediated inflammation, respectively, by blocking IL-5 and/or its receptor, preventing IL-4 and IL-13 signaling, affecting IL-33 pathway and blocking TSLP. None of these approaches has proved to be effective, probably because in COPD there is no dominant cytokine or chemokine and, therefore, a single mAb cannot be effective on all pathways. With a more in-depth understanding of the numerous pheno/endotypic pathways that play a role in COPD, it may eventually be possible to identify those specific patients in whom some of these cytokines or chemokines might predominate. In this case, it will be possible to implement a personalized treatment, but the use of each mAb will only be reserved for a very limited number of subjects.

Monoclonal Antibodies Targeting Alarmins: A New Perspective for Biological Therapies of Severe Asthma

Alarmins are innate cytokines, including thymic stromal lymphopoietin (TSLP), interleukin-33 (IL-33), and interleukin-25 (IL-25), which are mainly produced by airway epithelium and exert a prominent role in asthma pathobiology. In particular, several environmental factors such as allergens, cigarette smoking, airborne pollutants, and infectious agents trigger the release of alarmins, which in turn act as upstream activators of pro-inflammatory pathways underlying type 2 (T2-high) asthma. Indeed, alarmins directly activate group 2 innate lymphoid cells (ILC2), eosinophils, basophils, and mast cells and also stimulate dendritic cells to drive the commitment of naïve T helper (Th) cells towards the Th2 immunophenotype. Therefore, TSLP, IL-33, and IL-25 represent suitable targets for add-on therapies of severe asthma. Within this context, the fully human anti-TSLP monoclonal antibody tezepelumab has been evaluated in very promising randomized clinical trials. Tezepelumab and other anti-alarmins are thus likely to become, in the near future, valuable therapeutic options for the biological treatment of uncontrolled severe asthma.

Novel pharmacological therapies for the treatment of bronchial asthma

Asthma has long been recognised as a chronic inflammatory disease of the airways, often in response to inhaled allergens prompting inappropriate activation of the immune response. involving a range of cells including mast cells, Th2 lymphocytes and eosinophils and a wide range of inflammatory mediators. First-line therapy for treatment of persistent asthma involves the use of inhaled corticosteroids (ICS) in combination with inhaled β2-agonists enabling both the control of the underlying airways inflammation and a reduction of airway hyperresponsiveness. However, many patients remain symptomatic despite high-dose therapy. There is therefore a continued unmet clinical need to develop specifically new anti-inflammatory therapies for patients with asthma, either as an add-on therapy to ICS or as replacement monotherapies. The success of fixed dose combination inhalers containing both a bronchodilator and an anti-inflammatory drug has also led to the development of "bifunctional" drugs which are molecules specifically designed to have two distinct pharmacological actions based on distinct pharmacophores. In this review we will discuss these different pharmacological approaches under development for the treatment of bronchial asthma and the available pre-clinical and clinical data.

Allergic Aspects of IgG4-Related Disease: Implications for Pathogenesis and Therapy

IgG4-related disease (IgG4-RD) is a rare systemic fibroinflammatory disease frequently associated with allergy. The pathogenesis of IgG4-RD is poorly understood, and effective therapies are limited. However, IgG4-RD appears to involve some of the same pathogenic mechanisms observed in allergic disease, such as T helper 2 (Th2) and regulatory T cell (Treg) activation, IgG4 and IgE hypersecretion, and blood/tissue eosinophilia. In addition, IgG4-RD tissue fibrosis appears to involve activation of basophils and mast cells and their release of alarmins and cytokines. In this article, we review allergy-like features of IgG4-RD and highlight targeted therapies for allergy that have potential in treating patients with IgG4-RD.

Classes of drugs that target the cellular components of inflammation under clinical development for COPD

INTRODUCTION

The persistent inflammation that characterizes COPD and affects its natural course also impacting on symptoms has prompted research to find molecules that can regulate the inflammatory process but still available anti-inflammatory therapies provide little or no benefit in COPD patients. Consequently, numerous anti-inflammatory molecules that are effective in animal models of COPD have been or are being evaluated in humans.

AREAS COVERED

In this article we describe several classes of drugs that target the cellular components of inflammation under clinical development for COPD.

EXPERT OPINION

Although the results of many clinical trials with new molecules have often been disappointing, several studies are underway to investigate whether some of these molecules may be effective in treating specific subgroups of COPD patients. Indeed, the current perspective is to apply a more personalized treatment to the patient. This means being able to better define the patient's inflammatory state and treat it in a targeted manner. Unfortunately, the difficulty in translating encouraging experimental data into human clinical trials, the redundancy in the effects induced by signal-transmitting substances and the nonspecific effects of many classes that are undergoing clinical trials, do not yet allow specific inflammatory cell types to be targeted.

Tezepelumab: A Potential New Biological Therapy for Severe Refractory Asthma

Thymic stromal lymphopoietin (TSLP) is an innate cytokine, belonging to the group of alarmins, which plays a key pathogenic role in asthma by acting as an upstream activator of cellular and molecular pathways leading to type 2 (T2-high) airway inflammation. Released from airway epithelial cells upon tissue damage induced by several noxious agents including allergens, viruses, bacteria, and airborne pollutants, TSLP activates dendritic cells and group 2 innate lymphoid cells involved in the pathobiology of T2-high asthma. Tezepelumab is a fully human monoclonal antibody that binds to TSLP, thereby preventing its interaction with the TSLP receptor complex. Preliminary results of randomized clinical trials suggest that tezepelumab is characterized by a good safety and efficacy profile in patients with severe, uncontrolled asthma.

Chrysin Inhibits TNFα-Induced TSLP Expression through Downregulation of EGR1 Expression in Keratinocytes

Thymic stromal lymphopoietin (TSLP) is an epithelial cell-derived cytokine that acts as a critical mediator in the pathogenesis of atopic dermatitis (AD). Various therapeutic agents that prevent TSLP function can efficiently relieve the clinical symptoms of AD. However, the downregulation of TSLP expression by therapeutic agents remains poorly understood. In this study, we investigated the mode of action of chrysin in TSLP suppression in an AD-like inflammatory environment. We observed that the transcription factor early growth response (EGR1) contributed to the tumor necrosis factor alpha (TNFα)-induced transcription of TSLP. Chrysin attenuated TNFα-induced TSLP expression by downregulating EGR1 expression in HaCaT keratinocytes. We also showed that the oral administration of chrysin improved AD-like skin lesions in the ear and neck of BALB/c mice challenged with 2,4-dinitrochlorobenzene. We also showed that chrysin suppressed the expression of EGR1 and TSLP by inhibiting the extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK) 1/2 mitogen-activated protein kinase pathways. Collectively, the findings of this study suggest that chrysin improves AD-like skin lesions, at least in part, through the downregulation of the ERK1/2 or JNK1/2-EGR1-TSLP signaling axis in keratinocytes.

Oral inhalation for delivery of proteins and peptides to the lungs

Oral inhalation is the preferred route for delivery of small molecules to the lungs, because high tissue levels can be achieved shortly after application. Biologics are mainly administered by intravenous injection but inhalation might be beneficial for the treatment of lung diseases (e.g. asthma). This review discusses biological and pharmaceutical challenges for delivery of biologics and describes promising candidates. Insufficient stability of the proteins during aerosolization and the biological environment of the lung are the main obstacles for pulmonary delivery of biologics. Novel nebulizers will improve delivery by inducing less shear stress and administration as dry powder appears suitable for delivery of biologics. Other promising strategies include pegylation and development of antibody fragments, while carrier-encapsulated systems currently play no major role in pulmonary delivery of biologics for lung disease. While development of various biologics has been halted or has shown little effects, AIR DNase, alpha1-proteinase inhibitor, recombinant neuraminidase, and heparin are currently being evaluated in phase III trials. Several biologics are being tested for the treatment of coronavirus disease (COVID)-19, and it is expected that these trials will lead to improvements in pulmonary delivery of biologics.

Asthma-Associated Long TSLP Inhibits the Production of IgA

Thymic stromal lymphopoietin (TSLP) contributes to asthmatic disease. The concentrations of protective IgA may be reduced in the respiratory tract of asthma patients. We investigated how homeostatic short TSLP (shTSLP) and asthma-associated long TSLP (loTSLP) regulate IgA production. B cells from healthy donors were stimulated in the presence or absence of shTSLP or loTSLP; the concentrations of IgA, IgM, IgE, and IgG antibodies were determined in cell culture supernatants; and B cells were analyzed by flow cytometry. LoTSLP, but not shTSLP, suppressed the secretion of IgA but not of IgE. The type 2 cytokine IL-4, which in addition to loTSLP contributes to asthmatic disease, did not affect the production of IgA or the frequency of IgA+ B cells. Instead, IL-4 increased IgG production, especially of the subclasses IgG2 and IgG4. LoTSLP inhibited IgA secretion by sorted memory B cells but not by naïve B cells. Although loTSLP inhibited IgA production, the vitamin A metabolite retinoic acid promoted the secretion of IgA, also in the presence of loTSLP, suggesting that vitamin A may promote IgA production in asthma. Our data demonstrate that asthma-associated loTSLP negatively regulates the secretion of IgA, which may negatively impact the surveillance of mucosal surfaces in asthma.

Biologics in asthma management - Are we out of breath yet?

The biologics authorized for the add-on therapy of severe asthma are monoclonal antibodies (mAbs). Before they are considered for therapy intensification, the patient’s asthma endotype is determined on the basis of phenotypic characteristics. So far, 5 biologics are available that target the signaling pathways of the “T_H2-high” asthma endotype, in which cytokines of the inflammation cascade mediated by type 2 T-helper cells are upregulated. The corresponding phenotype of this inflammatory endotype is severe eosinophilic asthma, with elevated eosinophils, immunoglobulin E, and fractional exhaled nitric oxide (FeNO). In contrast, the heterogeneous “T_H2-low” endotype is not yet sufficiently understood. Frequently described in this variant is an increase of sputum neutrophils and an increased expression of the T_H17-mediated interleukin-17 signaling pathway. There are numerous biologics currently in clinical trials, the thymic stromal lymphopoietin (TSLP) mAbs in particular have shown promising results independent of the asthma phenotype.

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 mechanism of asthma and its novel molecular target therapeutic agent

Asthma is a chronic disease with major public health ramifications owing to its high morbidity and mortality rates, especially in severe and recurrent cases. Conventional therapeutic options could partially alleviate the burden of asthma, yet a novel approach is needed to completely control this condition. To do so, a comprehensive understanding of the molecular mechanism underlying asthma is essential to recognize and treat the major pathways that drive its pathophysiology. In this review, we will discuss the molecular mechanism of asthma, in particular focusing on the type of inflammatory responses it elicits, namely type 2 and non-type 2 asthma. Furthermore, we will discuss the novel therapeutic options that target the aberrant molecules found in asthma pathophysiology. We will specifically focus on the role of novel monoclonal antibody therapies recently developed, such as the anti-IgE, IL-5, IL-5Rα, and IL-4Rα antibodies, drugs that have been extensively studied preclinically and clinically.

Downregulation of miR-3934 in Peripheral Blood Mononuclear Cells of Asthmatic Patients and Its Potential Diagnostic Value

Background

The present study focused on the potential clinical significance of miR-3934 in the occurrence and development of asthma.

Methods

80 asthma and 80 healthy controls were recruited in this study. The peripheral blood mononuclear cells (PBMCs) and serum samples of the asthma patients as well as the healthy controls were isolated, and the expression levels of miR-3934 in PBMCs were examined by RT-qPCR methods. Furthermore, the relationship between the level of miR-3934 in PBMCs and the disease severity has been analyzed, and the potential diagnostic value of miR-3934 was evaluated by the receiver operating characteristics (ROC) curve. Finally, the expression level of IL-6, IL-8, and IL-33 have been detected using the ELISA kits, and Pearson's correlation analysis was performed to investigate the relationship between the level of miR-3934 in PBMCs and the serum expression of those inflammatory cytokines in asthma patients.

Results

miR-3934 was dramatically decreased in PBMCs of the asthma patients, and miR-3934 was markedly reduced in PBMCs of patients with severe asthma vs. mild asthma. Furthermore, ROC analysis showed that levels of miR-3934 in PBMCs can distinguish asthma patient, especially the severe asthma patients from the controls. Finally, the levels of miR-3934 in PBMCs were negatively correlated with the serum levels of IL-6, IL-8, and IL-33 in asthma patients, respectively.

Conclusions

miR-3934 was downregulated in PBMCs of asthmatic patients and may function as a potential diagnosis biomarker.

Therapeutic New Era for Atopic Dermatitis: Part 1. Biologics

Atopic dermatitis (AD) is a chronic, inflammatory cutaneous disease driven by immune dysregulation and skin barrier dysfunction. We are currently experiencing a new era of understanding of the pathogenesis of AD and, as a consequence, a new era of innovation in therapeutics, including small molecules and biologic therapy. Recently, advances in translational research have challenged the traditional AD pathogenesis paradigm of AD being solely a Th2-dominant disease. Other immune pathways seem to play a role in the complex AD pathophysiology, although the clinical relevance of these additional immune pathway abnormalities is unclear. Type 1, type 22, and type 17 pathway activation (with related cytokines/chemokines) have been demonstrated in the skin and blood of AD patients. Type 2 (interleukin [IL]-4, IL-13), IL-31, and type 22 (IL-22) pathway cytokines are increased in AD acute lesions. IL-22 induces both an epidermal hyperplasia at the onset of acute AD and a marked increase in the terminal differentiation S100 genes. This understanding of pathogenesis corresponds to a historic increase in therapeutic development in AD. The extreme clinical heterogeneity and the chronic progression of AD establish the need for newer, safer, and more effective treatments, control the disease, and improve the quality of life of affected patients.

Prospects for severe asthma treatment

Biological drugs are approved to treat patients with severe uncontrolled asthma and are directed against mediators of type 2 immunity. These agents are effective in reducing the risk of exacerbation, maintaining asthma symptom control and reducing the need of systemic corticosteroids. Although biological drugs have revolutionized the management of the disease, to date there are no head-to-head studies across the current available molecules and there remains the need of specific biomarkers for the diagnosis, prognosis and response to treatment. Moreover, there is still an urgent need to identify further molecular targets to offer effective treatments for those patients who are not responsive to the currently available biological drugs, by moving upstream in the inflammatory cascade to inhibit multiple inflammatory pathways and/or identify effective nontype 2 immunity mechanisms.

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.

TSLP as druggable target - a silver-lining for atopic diseases?

Atopic diseases refer to common allergic inflammatory diseases such as atopic dermatitis (AD), allergic rhinitis (AR), and allergic asthma (AA). AD often develops in early childhood and may herald the onset of other allergic disorders such as food allergy (FA), AR, and AA. This progression of the disease is also known as the atopic march, and it goes hand in hand with a significantly impaired quality of life as well as a significant economic burden. Atopic diseases usually are considered as T helper type 2 (Th2) cell-mediated inflammatory diseases. Thymic stromal lymphopoietin (TSLP), an epithelium-derived pro-inflammatory cytokine, activates distinct immune and non-immune cells. It has been shown to be a master regulator of type 2 immune responses and atopic diseases. In experimental settings, the inhibition or knockout of TSLP signaling has shown great therapeutic potential. This, in conjunction with the increasing knowledge about the central role of TSLP in the pathogenesis of atopic diseases, has sparked an interest in TSLP as a druggable target. In this review, we will discuss the autocrine and paracrine effects of TSLP, how it regulates the tissue microenvironment and drives atopic diseases, which provide the rationale for the increasing interest in TSLP as a druggable target.